ALBERT

Notizen: Physiological and vegetative performances of three prairie grasses were investigated to assess their adaptation to soil conditions at two strip mine sites and a nearby railroad prairie. Additionally, rhizomes of the species were transplanted to a pot experiment and grown in both field soil and greenhouse potting medium to investigate the extent to which plants are limited under field conditions. Field measurements of photosynthetic rate and stomatal conductance to water vapor were made on the three species monthly from May to late August. Gas exchange measurements on potted plants were made biweekly from early May to mid-July. In September, vegetative and flowering characteristics were measured on both field and potted plants. Field gas exchange rates were highest at one of the mines. Sorghastrum nutans had the highest rates at the mine sites, whereas Panicum virgatum had the highest rates at the prairie site. Potted plants from the prairie site usually exhibited the highest gas exchange rates, and Sorghastrum nutans had higher rates than Panicum virgatum and Andropogon gerardii. Potted plants in field soil generally had higher gas-exchange rates than plants growing in greenhouse potting medium, and potted plants had higher gas-exchange rates than field-grown plants. Vegetative and reproductive performance of field plants was highest at one of the mine sites. Potted plants in greenhouse medium had up to twice the vegetative and reproductive output as potted plants in field soil or plants growing in the field. The physiological and vegetative performance of these species indicates that they are well adapted to the soil conditions at these strip mine sites, and that they are a viable alternative to nonnative plantings for restoration.

Notizen: This paper describes a practical technique, tested experimentally, for rehabilitating degraded semiarid landscapes in Australia. This rehabilitation technique is based on the ecological principle that semiarid landscapes are spatially organized as patchy, source-sink systems; this patchy organization functions to conserve limited water and nutrients within the system. The aim was to rebuild vegetation patchiness, lost through decades of utilization of these landscapes as rangelands. Patches were reconstructed from large tree branches and shrubs obtained locally and placed in elongated piles along contours. These piles of branches were very effective in recreating productive soil patches within the landscape, as described in part I of this study. These new patchy habitats promoted the establishment and growth of perennial grasses. Although the foliage cover of these grasses declined into a drought, which started before the end of the experiment, plant survivorship remained high. This suggests that patches also function as refugia for organisms during droughts. The patches of branches remained robust and functional, even under grazing impacts, although plant growth and survival were significantly higher within an ungrazed paddock than in a grazed paddock.

Notizen: Aggressive growth by legumes may restrict the diversity of species-rich meadows recreated on sites restored after mineral extraction. We investigated the ability of mineral nitrogen (N) applications and spring grazing to control the legume component of such meadows. The use of N suppressed Trifolium repens but had no effect on other legume species or on the species richness, diversity, or equitability of the meadow community. Spring grazing significantly reduced the yield from the legume component of the meadow. This was accompanied by an increase in the equitability index of the community, suggesting that the aggressive nature of the legumes had been checked. Spring grazing may therefore provide a means of controlling aggressive legume growth and may maintain the diversity of species-rich meadows established on restored sites.

Notizen: Dogway Fork, West Virginia, is a second–order stream affected by acid precipitation. One goal of the Acid Precipitation Mitigation Program was to determine if the composition or population levels of benthic macroinvertebrates were affected by limestone neutralization of the acidic waters (pH 4.5). Two techniques were used to determine any effects: seasonal Surber samples and in situ bioassays with selected genera. Prior to treatment, macroinvertebrate densities were low but represented a diverse group of acidtolerant taxa. During treatment, fewer macroinvertebrates were collected in the treated segment than in the untreated control. This appears to be a result of a number of factors, including substrate, flows, drift, fish predation, accumulation of limestone fines, and changes in water chemistry. Bioassays suggest that the limestone fines were not directly detrimental to the organisms but may have limited available habitat in the mixing zone. Limestone treatment affected the species composition of Dogway Fork. During four years of treatment, several new acid-sensitive taxa were collected in the treated segment. Data suggest that, with continued treatment, populations of these taxa can be expected to increase.

Notizen: Thrush Lake, Minnesota, was treated with limestone in 1988 to evaluate the efficacy of protective base addition against the loss of sport fisheries in a sensitive, mildly acidic lake. Prior to treatment, the lake was stressed (pH 6.46, ANC 64 μeq/L) but not severely degraded by acidic deposition and had a macrophyte community typical of lakes in northeastern Minnesota with low acid-neutralizing capacity (ANC). This paper describes the changes observed in aquatic plant communities during the 5 years after treatment, as pH and ANC slowly returned to pretreatment levels. Sphagnum platyphyllum, intolerant of non-acid conditions, was completely eliminated from the lake. The charo-phyte, Nitella, that originally shared dominance in the deep littoral zone with S. platyphyllum, decreased in importance during the first 2 years after treatment. Two vascular plants, Potamogeton pusillus and Najas flexilis, were first found in the lake the year after treatment and were abundant for 2 years after liming, probably in response to a combination of more neutral pH and reduced cover of Nitella. As the ANC and pH slowly returned to pretreatment conditions, Nitella again increased in coverage and depth range, with a concomitant decrease in P. pusillus and N. flexilis. The moss, S. platyphyllum, had not reinvaded the lake by 1993, 2 years after its dramatic decline.

Notizen: 〈blockFixed type="quotation"〉Restoration ecology… is far more than merely the development of restoration protocols. It has much to offer the rest of ecology in the very fundamental matter of clarity of definition.Allen & Hoekstra (1987)

Notizen: The rehabilitation program conducted by Richards Bay Minerals (RBM) of areas exposed to opencast surface mining of sand dunes north of Richards Bay (28°43'S, 32°12'E) on the coast of northern KwaZulu-Natal Province commenced 16 years before this study and has resulted in the development of a series of known-aged stands of vegetation. By assuming that these spatially separated stands develop along a similar pathway over time, instantaneous sampling should reveal successional or other changes usually associated with aging and should provide an opportunity to evaluate the success of rehabilitation. We compare relative densities of pioneer and secondary species, species richness, and a similarity index of the herbaceous layer, tree, beetle, millipede, bird, and small-mammal communities of rehabilitating areas of known age with those of 30-year-old unmined forests and unmined forests of unknown age adjacent to the rehabilitating area. Species richness for all but the mammalian taxa increased with increasing age of rehabilitating stands. For all taxa but the mammals and herbaceous layer, the unmined stands harbored more species than the mined rehabilitating stands. The relative densities of pioneer species of all the taxa decreased with an increase in the age of rehabilitating stands, whereas those of the secondary species increased with an increase in habitat age. Similarity between unmined stands and rehabilitating stands of different ages increased with increasing regeneration age of rehabilitating stands, suggesting that rehabilitating communities, in terms of species composition and relative densities, are developing towards the status of unmined communities. Rehabilitation based on RBM's management program of limited interference is occurring and may result in the reestablishment of a coastal dune forest ecosystem. But rehabilitation resulting from succession depends on the availability of species sources from which colonization can take place. In the Richards Bay mining operation the present mining path is laid out so that such refuges are present.

Notizen: We studied the effects of soil handling operations during bauxite mining and restoration on the numbers and depth distribution of seed stored in the surface soil of the jarrah forest. Germinable seed stores were determined in four sites of undisturbed forest, these same sites after clearing and burning of forest residues, in the soil immediately following the construction of topsoil stockpiles, in the respread topsoil and then after deep ripping of the respread topsoil. Average density of germinable seed at four sites prior to disturbance was 352 m−2. After clearing and burning, the seed store had decreased to a mean 74% of the original forest soil seed store density. When the top-soil was stockpiled prior to respreading, the seed content was further reduced to 31% in freshly constructed stockpiles and had declined to 13% after 10 months in the stockpiles. After ripping of the respread topsoil the seed content was 16% of the original forest seed store density. In one site where the topsoil was directly stripped and respread with no period of stockpiling but with a period of fallow, the seed store was 32% after respreading and then increased to 53% of the original forest store after ripping. This increase may have been caused by an underestimate of the reserves due to insufficient heating of the samples to break dormancy in fire-requiring species. In the forest topsoils seed was concentrated in the upper few centimeters of the soil profile, whereas after the mining and restoration operations seed was evenly distributed throughout the returned soil profile to a depth of 20 cm. Small-seeded annual species, which were common in the forest seed store, were more sensitive to the soil handing operations and declined to very low numbers, whereas hard-seeded plant species such as Acacia spp. were less affected by the soil handling operations. Implications for bauxite mine revegetation operations include the recommendation that direct return of topsoil should be carried out wherever possible with a minimum delay between clearing, stripping, respreading, and ripping.

Notizen: Remote sensing provides a complementary approach to field sampling to assess whether restored wetland areas provide suitable habitat for the Light-footed Clapper Rail (Rallus longirostris levipes). Habitat requirements for the clapper rail are specified by the composition of vegetation species and their spatial extent in its nesting home range. A major salt marsh construction project has been completed at the Sweetwater Marsh National Wildlife Refuge (“the refuge”), San Diego County. In this paper we describe the application of image classification techniques to high-spatial-resolution digital video imagery (0.8-m pixels) to delimit patches of different marsh vegetation at the refuge. Using maps of vegetation types derived from multi spectral imagery, we estimated the area occupied by each vegetation type in potential clapper rail home ranges. Preliminary field-checking results indicate that this approach is an accurate, noninvasive and cost-efficient means of providing ecological information for restoration monitoring in southern California's remnant wetlands.

Notizen: Research was conducted to determine the efficiency and effects of chemically treating Dogway Fork, a West Virginia stream acidified by acid precipitation. We report on the water-powered rotary drum system used to apply calcium carbonate slurry to the stream. Two companion papers cover the biological and chemical effects of this treatment. The rotary drums provided near-continuous treatment over a 4–year period. Limestone aggregate (1.3–3.8 cm) high in calcium carbonate was ground within the drums into slurry form. The relatively low cost of aggregate and its ease of storage permitted economical treatment. The system compared favorably to other types of slurry dosers. Limestone particles deposited in the stream sediment continued over time to be dissolved. They were significant in the overall dissolution efficiency of the limestone treatment. This sediment calcite also provided supplementary neutralization when high flow requirements exceeded the drum station's dosing capability.

Notizen: Laurel Branch (Tennessee, U.S.A.), an acid-sensitive stream in the southern Appalachian Mountains, was limed as a part of the Acid Precipitation Mitigation Program funded by the U.S. Fish and Wildlife Service. Objectives were (1) to evaluate the effectiveness of stream liming by means of a hydropowered doser design, and (2) to monitor stream response(s) to increased pH and alkalinity. Precipitation in the region was documented to be acidic, with a mean pH of 4.54 in 1987. Preliming evaluations conducted from 1986 through 1988 depicted Laurel Branch as soft (hardness less than 5 mg/L CaCO3, pH 6.2–6.6), dilute (ionic strength less than 400 μeq/L), and lightly buffered (alkalinity less than 100 μeq/L). Because of the apparent relationship between flow and water chemistry, Laurel Branch was considered susceptible to episodic acidification caused by storms. In June 1989, a hydro–powered limestone doser was installed to treat the lower 3 km of the stream. Approximately 8.2 tonnes of crushed limestone were added during an 18–month treatment phase that concluded in December 1990. Technical and design problems with the doser reduced efficiency and limited the scale of liming through much of the first 6 months of operation. Design modifications and equipment upgrades in late 1989 corrected most of the problems and improved doser performance in 1990. No substantial chemical or biological changes were detected within the treated reach of Laurel Branch as a result of liming. Time–series statistical analyses showed small but significant changes in total alkalinity (10 μeq/L average increase) and dissolved calcium at all limed sites. pH (as hydrogen ion) increased 0.16 and 0.13 units at two limed sites that were 1 km and 2 km below the doser, respectively. At the lowermost limed site 3 km below the doser, a significant decrease in pH was detected which was probably flow-related. Mean length of age–0 (juvenile) and age-1 rainbow trout increased marginally during liming, suggesting improved fish growth, but increases were not significant. Densities of an acid-sensitive macrobenthic taxon (Baetis spp.) increased during liming, whereas densities of an acid-tolerant taxon (Leuctra spp.) remained unchanged. In general, observed biological changes were considered minimal; they were judged unrelated to liming but rather of seasonal and/or spatial origin. The regional drought of 1987 and 1988 was considered a confounding factor. With most of the baseline data collected during these years, vastly differing hydrology in 1989 and 1990 (“wet” years regionally) became problematic and may have distorted some responses and masked others. It is also possible that biological responses may have been delayed because of the small magnitude of chemical changes, particularly pH and alkalinity. A calcium mass budget estimated that up to 62% of the calcium added was accounted for in chemistry data from limed sites, with increases most visible in the spring and summer of 1990. Results indicated that, although the Laurel Branch watershed does receive acidic precipitation, current biological communities show high levels of integrity and little apparent degradation related to acidification. If watershed buffering capabilities are depleted from continued acidic deposition, however, stream biota may be at risk in the future.

Notizen: We evaluated 50-year-old bottomland forests in southwestern Kentucky restored from agriculture by planting and natural regeneration in terms of their development toward mature forests. We described and compared the structure and composition of the plant communities of three stands of each type (planted, naturally regenerated, and mature). Increment cores were analyzed to reconstruct developmental trends. Future trends were predicted from analyses of the midstory and understory composition. Both planting and natural regeneration adequately replaced the structural attributes of the historical bottomland forest. The existing structural differences are expected to diminish over time. Neither regeneration method replaced the wildlife value of the mature bottomland forests due to insufficient establishment and subsequent ingrowth of heavy mast species (particularly oaks and hickories). There was evidence that the understory species compositions of the restored forest types were similar to that of the mature stand type. All forests, including the mature stands, appeared to be succeeding from hydric to mesic species compositions as a result of human-altered hydrology and natural floodplain processes. We speculate that the historical bottomland species composition will probably not persist on any of the study sites in the long term.

Notizen: The semidesert grassland in southern Arizona has changed from a native grassland to a scattered Prosopis juliflora var. velutina (mesquite) woodland with an understory of African Eragrostis lehmanniana (Lehmann lovegrass) on many sites. To determine native grass restoration potential, seven species were direct seeded into E. lehmanniana stands that were left alive, burned, sprayed with an herbicide and then either left standing, or mowed. Initial native grass establishment was limited in the live standing treatment but was successful for all other treatments when either June or August sowing was followed by consistent summer precipitation and soil water availability. Four species, Bothriochloa barbinodis (cane beardgrass), Bouteloua curtipendula (sideoats grama), Digitaria californica (Arizona cottontop), and Leptochloa dubia (green spangletop) initially established most successfully, while only Muhlenbergia porteri (bush muhly) had consistently limited or no establishment. E. lehmanniana establishment from the seed bank was increased by canopy removal associated with burning. Densities of native grasses one year after successful initial establishment were much lower than that of E. lehmanniana. A possible revegetation strategy would be to spray emergent E. lehmanniana seedlings and surviving plants with an herbicide during the summer rainy season after spring burning. Native grasses could then be established by sowing in early August of that year or June and August of subsequent years until consistent precipitation produces a native grass stand.

Notizen: Books reviewed in this article: Land Ecology: An Introduction to Landscape Ecology as a Base for Land Evaluation, Land Management, and Conservation. Isaac S. Zonneveld

Notizen: Density, age structure, and growth rates of wild brook trout (Salvelinus fontinalis)and brown trout (Salmo trutta)in Whetstone Brook in northcentral Massachusetts were monitored for 4 years before and 3 years during limestone treatment to mitigate acidic conditions. The population density of brook trout increased significantly during treatment. Liming did not have any significant effects on the growth rates of brook trout or brown trout. Actual survival rates of brook trout and brown trout were not calculated due to the low density of both species, but more older individuals of both species were captured during the treatment period. Fulton condition factors (an index of fish condition) increased significantly for both brook trout and brown trout during treatment. Seven-day in situ bioassays of brown trout and rainbow trout demonstrated that liming improved the chemical environment for fish in Whetstone Brook. During a pretreatment bioassay in 1987, 100% rainbow trout mortality was observed at both the control and treatment stations in Whetstone Brook. Brown trout mortality was 67% in the control station and 70% in the treatment station. The pH during the 1987 bioassay averaged 4.90 in the control station and 4.99 in the treated station. During a bioassay conducted in 1990 after treatment began, rainbow trout mortality was 100% in the control station and 0% in the treatment station. Brown trout mortality was 17% in the control station and 0% in the treatment station. The pH during the 1990 bioassay averaged 5.23 in the control station and 6.60 in the treatment station. Analysis of total aluminum in the gills of fish from the 1990 bioassay revealed higher levels in fish from the control station than in those from the treatment station.

Notizen: We monitored the invertebrate fauna in Whetstone Brook for 3 years before and after limestone treatment to mitigate low pH conditions caused by acid precipitation. Sampling was conducted during the spring, summer, and fall by both qualitative and quantitative methods. The fauna in Whetstone Brook in the control and treatment sections was dominated by chironomids (Diptera), simuliids (Diptera), Leuctra (Plecop-tera) and Hydropsyche (Trichoptera) in both pretreatment and treatment periods. The acid-sensitive mayfly genera Epeorus increased during liming in the treated section of the stream but also declined during the same period in the control section. Annelida increased during the treatment period in both sections of the stream. The chironomid and black fly populations were not affected by liming. The lack of impact to the black fly population was surprising because larvae are obligate filter-feeders and feed on suspended seston in the same size range as the limestone slurry that was used to treat Whetstone Brook. Treatment did not change species diversity and taxa richness in the treated section of Whetsone Brook, but both indices declined during the treatment period in the control section of Whetstone Brook. This decline was attributed to the poorer water quality of the untreated section of Whetstone Brook during the treatment period, which was due to higher-than-average precipitation. Percent community similarity analysis indicated that the community composition changed more in the treated section of Whetstone Brook than in the control section as a result of treatment. We conclude that the invertebrate fauna in the treated section of Whetstone Brook was not negatively affected by liming, but that population density and diversity did not increase.

Notizen: A protective limestone treatment was applied to an acid-sensitive lake in northeastern Minnesota as part of the Acid Precipitation Mitigation Program. This 6–year study evaluated the impact of that treatment on lakes in the upper Midwest that experience episodes of acid stress but have not lost basic species integrity and community structure. Several changes in the fish community can be directly or indirectly attributed to the addition of 4.6 tonnes of calcium carbonate early in the third year of the study. An almost 30–fold increase in the population of Pimephales promelas(fathead minnow) a year after liming, based on mark-recapture estimates from trap netting and snorkeling, was attributed to a pH increase and a three-fold increase in the calcium concentration of the epilimnion. After the initial increase, the abundance of fathead minnows declined in subsequent years, as did the elevated pH and calcium concentrations. The Salvelimis fontinalis(brook trout) population also increased in the lake following application of limestone, but this was due in part to closing the lake to fishing. An increase in survival of stocked brook trout to age 1+ and an increase in growth of older brook trout after liming were attributed to the increased forage that the fathead minnows provided. Fathead minnows may have also reduced predation pressure on young brook trout by older brook trout. This study demonstrated that liming of a slightly acidic lake did not adversely affect the integrity of the fish community, and in fact may have increased the abundance and biomass of the forage fish community and indirectly increased the survival, abundance, and growth of brook trout.

Notizen: Seedling emergence of 12 selected northern jarrah (Eucalyptus marginata Donn ex Smith) forest species were investigated to assist Alcoa of Australia Ltd. in maximizing the establishment of topsoil species in rehabilitated bauxite mining sites. The species, which encompassed a range of seed weights (0.024 mg to 87 mg), plant families, seed-storage types, life forms, and germination requirements, were placed on the soil surface and at depths of 1, 2, 5, 10, and 15 cm under controlled conditions in a glasshouse. Ability to emerge from deep burial was found to depend on seed size for species that annually release their seed to the topsoil but not for species that store their seed on the plant. All selected species were capable of emerging from 2 cm depth of burial, but eight of the 12 species were either unable to emerge from 5 cm or showed a significant reduction in emergence from 5 cm depth of burial compared to optimally buried seed. This group included two small-seeded species, Stylidium calcaratum and Chamaescilla corymbosa; the major forest dominant, Eucalyptus marginata; the serotinous canopy-borne seed of Hakea amplexicaulis; and the wind-dispersed seed of Xanthorrhoea gracilis. A few seeds of the legume species Kennedia coccinea, Acacia pulchella, and Bossiaea aquifolium established seedlings from depths of 15 cm. Currently, Alcoa removes the upper 15 cm of topsoil separately from the underlying soil prior to the commencement of mining. This topsoil is respread at a similar depth following mining as part of the rehabilitation procedure. It is recommended that Alcoa continue to strip topsoil to a depth of 15 cm but investigate the option of re-spreading topsoil onto rehabilitated pits at a shallower depth to maximize establishment via the soil seed bank.

Notizen: We summarize the findings of a two-year study of vegetation and streambank erosion on incised streams. We conducted the first year of the research during the sixth year of a drought. During the second year of study, precipitation totals ranged from normal to 200% of normal. The focus of the study was to determine if vegetation established on a bank affects the erosion of or deposition on that bank. During the drought year, most banks showed relatively little change. During the high water year, 27% of all vegetated and 32% of all bare lower banks retreated more than 250 mm. This similarity between vegetated and unvegetated banks indicates that, on the streams studied, vegetation had little effect on bank erosion. Bank retreat was not related to near-bank velocities or to bank steepness. It is possible that herbaceous vegetation showed no effect on the incised streams because the streams were too far from a new dynamic equilibrium. The energy of the hydraulic system may have been greater than the vegetation could withstand.

Notizen: During the last two decades Chlamydotis undulata (houbara bustard) has declined drastically throughout its range, due primarily to over-hunting and severe habitat degradation. The threatened extinction of local populations led the National Commission for Wildlife Conservation and Development of Saudi Arabia to implement ex- and in-situ conservation measures: (1) a captive breeding program initiated in 1986, which achieved production of a self-sustaining breeding flock as well as a surplus for reintroduction by 1992; (2) establishment of a 13,775-km2 protected area around the last known breeding population in Saudi Arabia; (3) studies of wild birds, to determine densities, feeding ecology, and habitat requirements; and (4) studies on different release techniques (adult releases, sub-adult releases, feather-cut sub-adult releases, and covey releases), carried out since 1991 within the 2,300-km2 fenced and protected area of the Mahazat as-Sayd reserve.

Notizen: Interest in using native grass species for restoration is increasing, yet little is known about the ecology and genetics of native grass populations or the spatial scales over which seed can be transferred and successfully grown. The purpose of this study was to investigate the genetic structure within and among populations of Elymus glaucus in order to make some preliminary recommendations for the transfer and use of this species in revegetation and restoration projects. Twenty populations from California, Oregon, and Washington were analyzed for allozyme genotype at 20 loci, and patterns of variation within and among populations were determined. Allozyme variation at the species level was high, with 80% of the loci polymorphic and an average expected heterozygosity (an index of genetic diversity) of 0.194. All but two of the populations showed some level of polymorphism. A high degree of population differentiation was found, with 54.9% of the variation at allozyme loci partitioned among populations (Fst= 0.549). A lesser degree of genetic differentiation among closely spaced subpopulations within one of the populations was also demonstrated (Fst= 0.124). Self-pollination and the patchy natural distribution of the species both likely contribute to the low level of gene flow (Nm= 0.205) that was estimated. Zones developed for the transfer of seed of commercial conifer species may be inappropriate for transfer of E. glaucus germplasm because conifer species are characterized by high levels of gene flow. Limited gene flow in E. glaucus can facilitate the divergence of populations over relatively small spatial scales. This genetic differentiation can be due to random genetic drift, localized selective pressures, or both. In order to minimize the chances of planting poorly adapted germplasm, seed of E. glaucus may need to be collected in close proximity to the proposed restoration site.

Notizen: The restoration of the high botanical diversity of the premining jarrah (Eucalyptus marginata) forest is a major priority of rehabilitation following bauxite mining in southwestern Australia. This study investigated the effects of different ripping, seeding, and scarifying dates on the establishment of plants from propagules stored in the topsoil and from applied seed on areas being rehabilitated after mining. Seed stored in the topsoil, rather than applied seed, was the major contributor to plant diversity. Ripping late (April) or scarifying in June significantly reduced the number of species and numbers of individual plants that established from propagules in the topsoil. Species originating from broadcast seed were most numerous when the seed was broadcast in April or after scarifying in June. Scarifying before seeding, particularly in June, increased the establishment of species from the broadcast seed. To make best use of the applied seed, without jeopardizing the establishment of species from the topsoil, pits should be ripped and sown by April. We list a number of strategies that can help maximize plant numbers and botanical diversity on rehabilitated bauxite mines, which may also be of more general application for restoring the original native vegetation on disturbed sites.

Notizen: Annual legumes are often used as nurse plants for restoration projects, but two commonly used legume species were competitors at all densities with Artemisia californica (California sagebrush), a dominant shrub of southern California coastal sage scrub. Survival of Artemisia was not reduced by the lowest densities of the native Lupinus succulentus (arroyo lupine) at ratios of Artemisia to Lupinus of 1:1 or 1:3 or by the exotic Trifolium hirtum (rose clover) at the 1:1 density, but its survival was as low as 4% at the highest densities of Trifolium (1:16) and 1:32). Overall, Trifolium was more detrimental to survival of Artemisia, but the biomass of Artemisia was reduced by 90% or more in mixtures with both legumes even at the lowest densities of 1:1. The total soil nitrogen either did not change or decreased in two of the mixtures between planting and harvest dates, indicating that the legumes not only did not add nitrogen to the soil within one growing season but even depleted it in these two cases. Whereas Lupinus had greater aboveground bio-mass than Trifolium, it had a lower root density than Trifolium. The Artemisia root system was more shallow than either Trifolium or Lupinus, possibly explaining the poor growth of Artemisia in mixtures, The legumes were one to two orders of magnitude greater in aboveground biomass than Artemisia at the 1:1 ratio and therefore may be inappropriate choices as nurse plants. There is no evidence from this study that either of these legumes can act as nurse plants, even at the lowest ratio of one nurse plant to on shrub. Nurse plants are probably more important in harsher environments than in coastal sage scrub.

Notizen: Over the last 150 years butterflies have declined rapidly in both distribution and abundance in Britain. The majority of species declines can be linked with widespread habitat destruction that has occurred over the same period. The resulting concern for their conservation has provided many examples of attempts at restoration, most of which have been unsuccessful. The most common reasons for failure appear to be unsuitability of the habitat or lack of knowledge of the species' requirements, but in many cases the recording of the attempt is inadequate for any assessment to be made. Case studies of recent restoration efforts for four butterfly species are used to illustrate that successful restoration depends on detailed study of the species1 ecology and–particularly–habitat requirements, the ability and the resources to manage the habitat to provide those requirements, and a formal scientific approach that maximizes the information gained from the restoration process. As more land in Britain is taken out of intensive agricultural use, opportunities will increase for restoration programs. Prominent and popular species indicative of particular habitats can act as a focus for restoration of the habitat as a whole.

Notizen: Environmental Effects of Mining Earle A. Ripley, Robert E. Redmann, and Adele A. Crowder. Managing Habitats for Conservation William J. Sutherland and David A. Hill, editors. The Ecology of Woodland Creation Richard Ferris-Kuan, editor.

Notizen: We examined the long-term success of prairie planting on a former strip mine in northeastern Illinois. The site was reclaimed and planted with prairie species in the 1970s. Total biomass increased over time, largely as a result of an increase in biomass of non-prairie species. Biomass of prairie species remained unchanged because of an increase in Panicum virgatum (switchgrass) offsetting decreases in Sorghastrum nutans (Indian grass). Total biomass was less than values published for other restored prairies (78 ± 4 g/m2to 298 ± 72 g/m2 for our site, as opposed to 302-489 g/m2 for the Trelease Prairie). Mycorrhizal inoculum potential (MIP) was variable across the site. There were also relatively few species of mycorrhizal fungi present as spores. Gigaspora sp., Scutellospora sp., Glomus sp., Glomus geosporum, and Glomus cf. fasciculatum were identified from spores. On a transect dominated by warm-season (C4) prairie grasses, MIP of rhizosphere soil collected under these species was lower than the MIP of rhizosphere soil collected under exotic cool-season (C3) grasses on a transect dominated by C3 species. On a transect with mixed warm-and cool-season vegetation, however, MIP did not differ under the two vegetation types. These results suggest that within-site patchiness rather than cover type is influencing MIP. Values of MIP were lower than those reported for native Illinois prairie.

Notizen: Twenty-three “vital ecosystem attributes” (VEAs) were previously proposed to aid in quantitative evaluation of whole ecosystem structure, composition, and functional complexity over time. We here introduce a series of 16 quantifiable attributes for use at a higher spatial scale and ecological organizational level, the landscape. “Vital landscape attributes” (VLAs) should be useful in evaluating the results of ecological restoration or rehabilitation undertaken with a landscape perspective, provided that clear definitions and boundaries are agreed upon for the different spatial and ecological entities involved. Like VEAs, VLAs should be sensitive to changes wrought by human as well as to nonhuman factors leading to ruptures in flow processes or vegetation “switches.” They should be applicable over a wide range of landscape types and therefore aid in conducting rigorous interlandscape comparisons. We present three groups of VLAs: (1) landscape structure and biotic composition, (2) functional interactions among ecosystems within the landscape, and (3) degree, type, and causes of landscape fragmentation and degradation. Ecotones between ecosystems are touched upon by several different VLAs. Because conflicting terminology abounds in this area, we append a glossary defining the problematic terms used.

Notizen: Heightening human impacts on the Earth result in widespread losses of production and conservation values and make large-scale ecosystem restoration increasingly urgent. Tackling this problem requires the development of general guiding principles for restoration so that we can move away from the ad hoc, site- and situation-specific approach that now prevails. A continuum of restoration efforts can be recognized, ranging from restoration of localized highly degraded sites to restoration of entire landscapes for production and/or conservation reasons. We emphasize the importance of developing restoration methodologies that are applicable at the landscape scale. Key processes in restoration include identifying and dealing with the processes leading to degradation in the first place, determining realistic goals and measures of success, developing methods for implementing the goals and incorporating them into land-management and planning strategies, and monitoring the restoration and assessing its success. Few of these procedures are currently incorporated in many restoration projects. The concept that many ecosystems are likely to exist in alternative stable states, depending on their history, is relevant to the setting of restoration goals. A range of measures, such as those being developed to measure ecosystem health, could be used to develop “scorecards” for restoration efforts. Generalizable guidelines for restoration on individual sites could be based on the concepts of designed disturbance, controlled colonization, and controlled species performance. Fewer explicit guidelines are available at the landscape scale, beyond nonquantitative generalities about size and connectivity. Development of these guidelines is an important priority so that urgent large-scale restoration can be planned and implemented effectively.

Notizen: Seagrass ecosystems fulfill ecologically and economically valuable functions in coastal marine environments. Unfortunately, seagrass beds are susceptible to natural and human disturbances, and their distrubution is declining worldwide. Although intentional disturbance of seagrass beds must be mitigated pursuant to U.S. law, to date mitigation of seagrass beds has not prevented a net loss of habitat. Transplantation of vegetative material from small areas of nearby beds is the primary method of seagrass mitigation. Restoration research on seagrasses has focused primarily on establishment of the plants and secondarily on the functional equivalency of the habitats. We questioned whether transplanted seagrass beds were comparable to “natural” beds in terms of genetic diversity and structure. We sampled Zostera marina L. (eel-grass) from 12 sites in the highly urbanized area of San Diego County and from pristine sites in Baja California. Using allozyme electrophoresis, we determined that genetic diversity (percentage of polymorphic loci, allele richness, expected and observed heterozygosities, and proportion of genetically unique individuals) was significantly reduced in transplanted eelgrass beds. Eelgrass from Baja California exhibited the highest genetic diversity. Based on Wright's F statistics, most of the genetic variation was distributed within rather than among sites (FST= 0.139), and the degree of genetic structure was only moderate at the greatest geographical scale (San Diego—Baja). Using a spatial statistical analysis (second-order analysis), we found virtually no evidence for nonrandom distribution of alleles or genotypes at scales of 3–50 m within beds. We discuss several hypotheses for reduced genetic diversity in transplanted eelgrass beds, including transplantation protocol, small size of transplantations, and reduced or failed sexual reproduction.

Notizen: Few early examples of forest restoration projects are extant in the formerly forested parts of eastern North America. In this paper I present the history and status of an early forest restoration project in a denuded gravel pit in Ontario, Canada. The site was part of a deciduous forest until 1840, at which time forest clearing occurred. From 1874 to 1886 the site was exploited as a gravel pit. In 1887, under the direction of William Brown, it was planted with 14 species of coniferous and deciduous trees, of which 10 are still present. No soil preparation was carried out. The trees were pruned for 7 years, but in 1892 intensive maintenance ceased. In the 107 years since planting, the site has acquired some structural characteristics similar to the surrounding native deciduous forest, but it retains characteristics of an artificial community. Canopy cover has increased from 85% to over 95% since 1930 and is primarily Juglans nigra and Acer platan aides, Survivorship and current growth rates of native and exotic taxa have been similar. Recruitment patterns suggest that J. nigra and A. platanoides will dominate the canopy over the next century. The site is a useful example of the progress and problems created by attempts at forest restoration today.

Notizen: We monitored several herbaceous species for revegetating motorway slopes in Catalonia, Spain, a Mediterranean country. Two main kinds of treatments were applied: hydroseeding on bare marl, chalk, and slates, and hydroseeding on embankments over gentler slopes, where soil materials previously removed were spread before hydroseeding. The greatest herbaceous cover was obtained by hydroseeding after soil replacement, and marl was the most suitable bare substratum for hydroseeding. Physical characteristics such as schistosily plane in slates and softness or surface irregularity in chalk determined the outcome of revegetation efforts. The most immediate stabilization of soils was obtained on southern exposures with autumnal applications. Grasses, markedly of the genera Lolium and Festuca, were dominant in the herbaceous cover at the end of the monitoring period. Natural invasive vegetation was composed of ruderal species, but no representatives of the adjacent forest or maquis community were found.

Notizen: Books reviewed in this article: Restoration Ecology in Europe Krystyna M. Urbanska and Krystyna Grodzinskn, editors Ecology and Management of Invasive Riverside Plants Louise C. de Wnal, Lois E. Child, P. Max Wnde, and Joint H. Brock, editors Restoring Prairie Wetlands: An Ecological Approach Susan G. Galatowitsch and Arnold G. van der Valk

Notizen: A rehabilitation procedure designed to reestablish resource control processes in a degraded Acacia aneura woodland was successful in improving soil nitrogen and carbon content, exchange properties, and water infiltration rates. Soil respiration rates and soil fauna populations increased, and soil temperatures were moderated. The procedure comprised laying piles of branches in patches on the contour of bare, gently sloping landscapes, with the expectation that soil, water, and litter would accumulate in these branch piles, thus improving the soil habitat and its productive potential. The procedure was derived from landscape function analysis, indicating that surface water flow was the principal means of resource transfer in these landscapes. Under degradation such overland flow results in a loss of resources. This rehabilitation procedure reversed loss processes, resulting in gains in the productive potential of soils within patches. This procedure was successful despite grazing pressure being maintained throughout the experiment.

Notizen: Ursus americanus(black bear) predation could limit the success of the proposed restoration of Rangifer tarandus (woodland caribou) to Minnesota. The problem was recently identified as a major factor in the failure of a similar restoration effort in Maine. During the summer of 1991 we conducted a survey in the region of the proposed restoration, using bait stations to identify bear presence. Four settings were sampled: islands with campsites, islands without campsites, mainland areas with campsites, and mainland areas without campsites. Results from the survey suggest that black bears use areas with campsites more than those without. Whereas caribou may use islands preferentially for calving to escape predation, islands with campsites may be unfavorable for caribou calf survival due to frequent bear visitation.

Notizen: The past 40 years have seen the legal and policy framework for nature conservation in Britain extend from protection and preservation to include enhancement through techniques such as ecological restoration and habitat creation. Clear objectives need to be set for ecological restoration and habitat creation schemes because the processes involve human intervention in combination with natural factors operating over time. Objectives are required for both management and monitoring in order to enable measurement of success or failure. The most effective way to achieve high-quality restoration and creation schemes is to define the output of the process—a habitat, vegetation type, or biological community. The better the definition of the output, the greater the need to define the inputs and the nature of the intervening processes. Ecologists and environmental managers have a key role to play in establishing the degree of definition necessary in order to achieve a particular objective.

Notizen: Whetstone Brook is a trout stream located in north-central Massachusetts that is degraded by acid precipitation. The stream was treated with 56 tonnes of powdered limestone by a prototype, water-powered doser as part of the U.S. Fish and Wildlife Service's Acid Precipitation Mitigation Program. The goal of liming Whetstone Brook was to raise the pH to 6.5 and acid neutralizing capacity (ANC) to at least 50 μeq/1 in a 3.2-km reach. This goal was achieved despite the fact that during the 31 months of treatment stream flow was 37% higher than during the pretreatment period. During the treatment period, pH averaged 6.54 and ANC averaged 69.75. During the pretreatment period average pH was 5.97 and average ANC was 20.26. In the control section of Whetstone Brook, both pH and ANC were lower during the treatment period than during the pretreatment period. During treatment, monomeric aluminum, a form toxic to fish, declined in the treated section and increased in the control section. Total calcium, sediment calcium, and pore-water calcium increased in the treated section during treatment but declined in the control section. The other base anions and cations, nutrients, and physical parameters were not significantly affected by liming.

Notizen: Books reviewed in this article: Redesigning the American Lawn: A Search for Environmental Harmony. F. H. Bormann, D. Balmori, and G. T. Geballe Seasonally Dry Tropical Forests Stephen H. Bullock, Harold A. Mooney, and Ernesto Medina, editors

Notizen: A limestone slurry was sprayed on the surface of Thrush Lake, a small headwater lake in northeastern Minnesota, to test a treatment designed to protect acid-sensitive waters from anthropogenic acidification. The 6-year study, consisting of pretreatment, transition, and post-treatment phases, was part of the four-state Acid Precipitation Mitigation Program directed by the U.S. Fish and Wildlife Service. Measured water-chemistry parameters, including acid-neutralizing capacity, pH, dissolved calcium, and dissolved inoroganic carbon, increased following treatment, although local climatic conditions influenced the magnitude and duration of the chemical changes. Physical changes to the lake, other than an increase in conductivity and a short-term alteration of water clarity subsequent to treatment, were not documented. The composition of the zooplankton community was altered, with the proportion of rotifers increasing after treatment. Individual zooplankton species showed a variety of changes in abundance that were associated with treatment over both seasonal and multi-year intervals. For example, Holopedium gibbemm was absent from lake samples immediately following treatment and recovered within a season, whereas Diaptomus minutus and Keratella taurocephala populations were reduced after treatment and had not recovered by the end of the study. Alternately, Asplanchna priodonta increased in abundance after treatment. These observed abundance patterns were generally consistent with previzous acidification or base-addition studies. In contrast, the changes in community composition of zooplankton did not consistently fit patterns developed from regional studies across water-chemistry gradients. These differences emphasize the importance of biotic as well as abiotic factors in controlling zooplankton community composition.

Notizen: The restoration of chemically degraded rivers, lakes, and estuaries with large watersheds and pollution sources that are primarily diffuse in nature requires the grading of thousands of kilometers of tributary streams. Many population-and community-oriented biomonitoring methods have been developed that avoid the cost limitations of chemical/biomarker/bioassay approaches and the serious limitations of single-factor analysis as related to complex systems. In this study of the coastal plain and piedmont geomorphologic provinces of the Chesapeake Bay watershed, we have demonstrated a set of quantitative measures based on analysis of macrophyte populations that provide statistically significant separation of streams in accordance with their state-issued water quality rating. Macrophytes can be abundant and diverse in lower-order streams, and they demonstrate patterns of community structure and diversity similar to those of other organisms developed for biomonitoring of stream degradation. Unlike organisms previously and extensively used in biomonitoring techniques, however, macrophytes are considerably easier to identify and quantify. In addition, macrophyte techniques provide a range of measures of increasing sensitivity from species numbers at a few sites, to the presence/absence and abundance of indicator species, and, finally, to a diversity analysis based on easily identified species at an extended number of sites. We suggest that the ease of utilization of this methodology will allow repeated surveys of all streams in large watersheds with the invertebrate, fish and diatom biomonitoring to biomarking and chemical bioassays and finally analytical chemistry, progressively applied to verify and then identify specific pollution sources (“hot spots”) in a more limited number of problem streams.

Notizen: Alliaria petiolata (garlic mustard), an exotic plant species, has invaded woodlands in several areas in mid-western and northeastern United States and adjacent Canada, and it is displacing the indigenous under-story flora. This study was conducted to provide information about the species' biology that might be useful in controlling its spread in native woodlands. The plant is a strict biennial in North America, spending the first year of growth as a basal rosette. This period of relatively slow growth is followed by a period of rapid shoot elongation (1.9 cm/day) during early spring of the second growing season. The plant is capable of cross- and self-pollination, although pollination and stigma receptivity occur before the flower is open, so autogamy is the most likely breeding system. Garlic mustard invests 20.4% of its biomass in reproductive effort, with an annual seed rain of 15,000 seeds/m2. Seed dispersal from fruits begins in early July and continues into October. Most seeds germinate in the spring following the year in which they were produced. Seedling recruitment is high (8.3–18.0 seedlings/cm2), but only about 7.5% of the plants survive to maturity. The success of the plant in invading woodlands appears to be related to (1) its autogamous breeding system that allows a single individual, or a few individuals, to establish populations of genetically similar but interfertile individuals; (2) high seed production, permitting establishment of large numbers of individuals; and (3) rapid growth during the second growing season, which increases its competitive ability. Because of garlic mustard's ability to occupy understory habitats successfully, it may be unrealistic to expect to eliminate the plant from many habitats it has already invaded.

Notizen: This study investigates the influence of gap width and turf type on the growth of planted seedlings of the Australian forb Bulbine bulbosa (bulbine lily) and subsequent recruitment of this species from self-sown seed. In a low-productivity turf of Danthonia setacea (bristly wallaby grass), planted Bulbine seedlings established satisfactorily in all gaps 50 mm wide or larger. In highly productive turfs of Festuca arundinacea (tall fescue) successful, establishment and growth of planted seedlings required a competition-free gap more than 200 mm wide. Successful recruitment of self-sown Bulbine seedlings was observed in all gap widths in Danthonia turfs. In Festuca, however, seedling recruitment was low, irrespective of gap width. The results are related to establishing Bulbine bulbosa in habitat reconstruction programs in southeastern Australia.

Notizen: We conducted a study of the flood tolerance of nine wetland tree species on seven soil types. Seedlings were subjected to 11 months of continuous shallow inundation or moist soil conditions on three mineral soils, two organic soils, a manufactured soil designed to mimic the practice of layering muck over mineral soil, and a stockpiled topsoil. Taxodium ascendens, T. distichum, Acer rubrum, and Pinus serotina suffered no mortality; Fraxinus carolininna (1%), Liquidambar styraciflua (8%), P. elliottii (8%), and Gordonia lasianthus (24%) suffered low to moderate mortality; and Persea palustris (46%) suffered significant mortality. In general, greatest net height and total biomass were achieved on moist organic soils, and least net height and total biomass were achieved on stockpiled topsoil and inundated soils. Responses to hydrological conditions were less pronounced for Taxodium spp. If the results of this experiment are transferable to the field, then Acer rubrum, Fraxinus caroliniana, Pinus serotina, Taxodium ascendens, and Taxodium distichum seedlings can reasonably be expected to survive at least one year under a broad range of hydrological and edaphic conditions. With the exception of Taxodium spp., first-year growth for the species of this study can be facilitated by maintaining moist but not inundated conditions. These findings suggest that transfer of organic soils will benefit restoration and creation efforts, and that layering organic soil over mineral soil is more effective than using mineral soils or stockpiled topsoil.

Notizen: Experimental plots of pulverized fuel ash (PFA), alone or mixed with flue gas desulphurization (FGD) gypsum, were seeded with topsoil from areas where PFA had been revegetated naturally, or with estuarine soil. Plots containing fresh PFA became more saline during the first three years due to formation of a salt crust, and these plots experienced colonization by halophytic species. Plots initially containing 2-year-old PFA declined in salinity throughout the experiment and were colonized by a richer plant community dominated by legumes. A total of 57 plant species was recorded in the two experiments. Of these, Melilotus officinalis (ribbed melilot), Medicago lupulina (black medick), Vulpia myuros (rat's tail fescue), and Puccinellia maritima (common saltmarsh grass) showed commercial potential for stabilizing these wastes, and by implication other saline or high-boron materials.

Notizen: Limestone neutralization of the acidic water of Dog-way Fork in West Virginia resulted in significant improvements in both water quality and fish populations. Pretreatment water chemistry showed the stream to be highly acidified by acid precipitation, with pH under 5.0 and high aluminum concentrations. During treatment, the goals for the target area of pH 6.5 and acid-neutralizing capacity of 50 μmeq/L were met for 75.8% and 67% of the time, respectively. A pH 6.0 or above was maintained over 93% of the time. Monomeric aluminum concentrations were reduced significantly, and calcium to hydrogen ionic ratios were over 10 in the target area. Prior to treatment, no resident fish population was found in Dogway Fork. During five years of treatment, conditions were favorable for fish reproduction and survival. Eight fish species inhabited the stream, six were reproducing there, and a fishable brook trout population was established.

Notizen: Abstract. Four field experiments were carried out on cultivated shallow fen peat overlying acid gyttja (lake mud) soil. The accessibility of the generally ample supply of physically available water was restricted by a limited root depth caused by low pH and high levels of aluminium in the subsoil. In order to improve the nutrient status and the crop water supply of the soils liming, deep cultivation, P-fertilization and irrigation were tested in field experiments comprising these four main treatments and their combinations. Liming and P-fertilization of the topsoil, irrigation and deep cultivation in combination with deep liming improved crop yields. Deep cultivation without liming had a negative effect on yield in most years.

Notizen: Abstract. The effect of liming and deep cultivation on soil properties and root development was investigated in two cultivated shallow fen peats resting on acid gyttja (lake mud) soils. Root growth was in general dependent on soil pH and aluminium content of the soil. A soil pH (H2O) below 5 adversely affected roots and a pH below 4 severely restricted root growth. Liming of the topsoil or the subsoil and to some extent deep cultivation improved root growth. Increased rooting depth made it possible for plants to utilize soil water to a greater depth in the profile and to support a larger crop yield.

Notizen: Abstract. Flow and nitrate concentrations were measured weekly for four years at twelve stream-water monitoring sites in a catchment in the English Midlands designated as a Nitrate Advisory Area. Farm surveys and satellite images have provided soil and land use information. Measurements show the nitrate load to be dominated by discharge, with large variability due to differing weather conditions from year to year. Within-year variability in nitrate concentrations is also related to weather conditions, with high concentrations when field capacity is reached if this occurs late in the year. There is also clear evidence of dilution of nitrate during intense storms. The effect of changing weather conditions makes it impossible to identify catchment-scale changes in leaching due to changes in agricultural practice over a period as short as four years. Measurements from a major spring in the catchment show an increasing trend in nitrate concentrations through the period. There is some evidence that the greatest N leaching to streams in the catchment is associated with intensive grassland on soils which are naturally poorly drained.

Notizen: Abstract. At De Marke experimental farm, data on water and nitrogen flows in the unsaturated zone were gathered on two grazed pastures on sandy soils during the years 1991 to 1994. These provided a basis for calibration and validation of simulation models. The different levels of nitrate-N concentrations of the two plots could largely be explained by differences in crop uptake and simulated denitrification as influenced by different groundwater levels. The irregular distribution of excreta was taken into account by a simulation study quantifying the variability of nitrate-N concentrations under a grazed field. The resulting distribution of simulated nitrate-N concentrations explained the average and peak values of the measured concentrations. Temporal variability of weather was used to assess the nitrate leaching risk under urine patches deposited in either July or September. At site A the probability of exceeding the EC-directive by drinking water (11.3 mg/1 nitrate-N) under a urination deposited in either July or September was respectively 10 and 25%. The average field concentration at this site will hardly ever be a high risk for the environment under the current farm management. At site B the EC-directive will be exceeded under any urine patch in almost 100% of the years, affecting the field average concentration. In field B careful grazing management would result in less nitrate leaching, but the environmental goals would not be reached.

Notizen: Abstract. A field experiment on a coarse sand (1987–92) was conducted with spring barley (Hordeum vulgare L.), in order to evaluate the effects of increasing N fertilization on nitrate leaching under temperate coastal climate conditions. The N fertilizer levels were 60 and 120 kg N/ha. The experiment was conducted on a 19-year old permanent field trial with continuous spring barley, initiated in 1968, and included treatments with ploughing in autumn or spring, with or without perennial ryegrass (Lolium perenne L.) as a catch crop undersown in spring. Prior to 1987, the low and high levels of N fertilizer were 70 and 150 kg N/ha, respectively. To calculate nitrate leaching, soil water samples were taken from a depth of 0.8 m using ceramic cups. The average annual nitrate leaching from plots with 60 and 120 kg N/ha was 38 and 52 kg N/ha/y, respectively. The increased leaching associated with increasing fertilizer application was not caused by inorganic N in the soil at harvest, but rather by greater mineralization, mainly in autumn. Growing of a catch crop was relatively more efficient for reducing nitrate leaching than a long-term low fertilizer application. A 50% reduction in N application decreased average yield by 26%, while nitrate leaching decreased by 27%.

Notizen: Abstract. Whey, the liquid byproduct of cheese production, can improve the physical condition of sodic soils or those susceptible to erosion by increasing their aggregate stability. The effects of whey on soil hydraulic properties, however, are not known. In this experiment, we used tension infiltrometers to determine whey effects on infiltration rates of water (at suctions ≥ 30 mm of water) and unsaturated hydraulic conductivities of Ap horizons of a Portneuf silt loam (coarse-silty, mixed, mesic Durixerollic Calciorthid) after a winter wheat crop. In the summer of 1993 near Kimberly, ID, USA, liquid whey was flood-applied at either 0, 200,400, or 800 t/ha to plots planted to wheat the previous September. At suctions of 60 and 150 mm, infiltration rates decreased linearly by about 0.7 μm/s with each additional 100 t/ha of whey applied. As whey applications increased, hydraulic conductivities at 60 mm suction increased slightly but as applications exceeded 400 t/ha decreased significantly. We concluded that summer whey applications up to 400 t/ha would not adversely affect surface hydraulic properties.

Notizen: Abstract. The potential for using coal-derived humic substances to improve the available water holding capacity (AWC) and aggregate stability of typical Mediterranean soils was evaluated in the laboratory using an agricultural surface (0–20 cm) soil from each of three regions of Italy, (Sicily, Tuscany and Venetia) and five rates of humic acids (HA), 0,0.05,0.10,0.50 and 1.00 g/kg. There were significant (P 〈 0.05) differences between the field capacity (FC), permanent wilting point (PWP), and available water capacity (AWC) values of the controls and those treated with 0.05 g/kg of the HA. Beyond this rate, differences in these properties were not significant. At the 1.00 g/kg HA rate, the relative improvements in AWC over the three controls were 30%, 10% and 26%. Low rates (0.05 to 0.10 g/kg) of HA were also needed to obtain a 40 to 120% improvement in aggregate stability of these soils relative to the controls. These results indicate that the addition of highly humified organic matter such as coal-derived humic substances can improve the structural and water retention properties of degraded arable soils. However, since there is not yet any direct evidence that these humic materials can ameliorate soils under field conditions, field studies will be needed to validate these results.

Notizen: Abstract. A study of soil water erosion was undertaken between 1982 and 1986 in 17 areas of lowland England and Wales. Air photographs were taken annually, these were checked to identify erosion events and a sample of 392 eroded fields visited between 1983 and 1986. Erosion was most common in fields drilled with winter cereals (39% of cases), which was the crop considered by farmers to be at greatest risk of erosion. Estimated crop losses were greater than 10% for only 5% of fields. ‘Clean up’ costs were incurred on 15% of the fields studied. Attempts at contour ploughing and planting/drilling appeared to result in more severe erosion, than working up and down the slope. Farmers considered that the main reason for erosion on their farms was arable cropping, and the presence of compacted wheelings/tramlines. Fields where hedges had been removed in the last 20 years suffered from erosion marginally more frequently than other fields. Field slope alone was not found to be a major factor in the occurrence of erosion, with almost 60% of erosion events on slopes of less than 7°. Erosion occurred at least every other year in half the fields studied.

Notizen: Book reviews in this article: Soil Resilience and Sustainable Land Use Edited by D. J. Greenland and I. Szabolcs.

Notizen: Abstract. Using the simulation model MACRO, this paper investigates the likely consequences of reduced irrigation inputs on the water and salt balance and crop growth in a drained, saline clay in a Mediterranean climate (Marismas, SW Spain). The model was first successfully validated against field measurements of the soil water and chloride balance, water table depths and drain outflows in the 1989 growing season. Three-year simulations were then performed assuming two different irrigation applications (60 and 75% reductions from the 1989 amount) and two different frequencies (12 or 6 irrigations per growing season). The model predictions suggested that reduced irrigation may lead to up to a 15%) increase in the chloride content of the soil profile after 3 years. Also, despite overall reductions in water discharge, slight increases in chloride leaching via field drains (c. 4 to 8%) were predicted. The model demonstrated that encroachment of salt into the soil profile may he exacerbated by the non-equilibrium nature of water flow and solute transport (‘by-passing flow’) in structured clays. With reduced water supply for irrigation, more frequent applications may give marginally better crop yields for the same quantity of irrigation but at the expense of slightly increasing salt concentration in the root zone.

Notizen: Abstract. A model was developed to estimate daily evapotranspiration and root zone soil moisture changes appropriate for scheduling irrigation, incorporating a modified version of the Penman-Monteith equation.The model was field tested during 1992–94, for potatoes and sugarbeet, by comparing modelled root zone soil moisture changes with field measurements taken using neutron probes. The study confirmed the accuracy of the model when predicting crop water use and soil moisture change. Linear regression of measured versus modelled data exhibited a slope of 0.99 and an intercept close to and not significantly different from zero. The relationship accounted for 80% of the variation.

Notizen: Abstract. Regular application of slurry manure in large quantities is thought to degrade soil structure and increase erodibility. One hypothesis links this to the large input of potassium which increases the exchangeable potassium percentage (EPP) and, thereby, dispersion. The effect of EPP on erodibility was quantified in three experiments. In the laboratory, eleven rainfall experiments were conducted using a silty topsoil from a typic Hapludalf which was fertilized to EPPs of 4 to 18%. Field rainfall experiments on 22 Inceptisols and Alfisols were used to examine whether the long-term application of monovalent cations (Na+, K+ and NH4+) with slurry manure had changed soil properties, especially erodibility. In addition, erodibilities of 32 soils determined with natural and simulated rains were taken from literature. The experiments on these 65 soils together covered a wide range of soils, slopes and rainfalls. Dispersion by a large percentage of highly hydrated ions (K+, Na+) reduced the infiltration rate faster, caused runoff up to 5 min earlier, and increased sediment concentrations by 15g/l compared to low EPP soils. These changes increased soil erodibility of the Universal Soil Loss Equation (USLE) by 0.021 t × h/N × ha (where N = Newtons) for each 1% increase in EPP + ESP (exchangeable sodium percentage). The ESP contributed little to this increase as ESP was less than 1/10 of EPP in the experiments.Fields with long-term manure application had similar chemical, physical and microbiological soil properties as fields without slurry manure except for slightly greater pH (+ 0.6) and P (+ 17 mg/kg) values. We conclude that, as long as the potassium input and output are balanced, the long-term use of slurry manure does not increase erodibility.

Notizen: Abstract. A model was developed to predict evapotranspiration and soil moisture changes, which could be used either for scheduling irrigation or crop water-use studies. The general form of the model is reported here, and its validation for sugarbeet and potatoes is described in a subsequent paper. The soil characteristics required are depth of topsoil, texture or available water capacity of topsoil and subsoil, and whether a significant slope exists. The plant characteristics required are species and planting date. Meteorological data used to calculate potential evapotranspiration are obtained from the Meteorological Office synoptic network, but local rainfall data are preferred.The model estimates potential evapotranspiration of a reference crop, and uses this to model canopy and root development for all crops at each location. Available options allow for observed data on canopy or root development to be incorporated into the simulations. Estimates of potential evapotranspiration for each crop are then adjusted to allow for the effects of water stress, taking soil characteristics, root depth and evapotranspiration demand into account.The model enables growers to reduce the risks of under- or over-watering their crops and has proved successful in irrigation management.

Notizen: Abstract. A land evaluation using unsophisticated data successfully predicted yield ranges of various crops in Burundi. Yields of wheat, pea, bean, maize and potato predicted from data for climate, soil and land use technology were compared with observed yields from farm trials and from seed station and research station trials. The predicted range of yield for each crop suitability class enclosed the mean farm yields 13 times out of 16 and yields on seed stations and research stations 10 times out of 15 and 14 times out of 21 respectively. The variability of the observed yields exceeded the predicted range of yields. The method is considered as validated. The method appears to be applicable for multi-year studies at a broad scale, but yield variation according to the weather from year to year is not accounted for. The variances of the yields on farms are greater than the variances in seed station and research station trials.Since the method predicts correctly the mean regional farm yields, it could be useful for land use planning, research into optimal regional cropping specialisation, studies on food policy, and for evaluation of economic return and sustainability of different crops.

Notizen: Abstract. Usual residue-management options are to remove the residue, use it as mulch with or without undercutting or to incorporate it into the soil. While the role of surface mulch in evaporation has been widely studied, the information on the effect on evaporation of mulch with undercutting or residue incorporated into soil, particularly in relation to soil type and evaporativity (Eo) is lacking. We studied the effect of wheat straw used in various ways on the course of evaporation loss from soil columns with three soils at Ludhiana, India and one soil at Bushland, Texas, USA, under two Eo's Energy-limited evaporation rates under mulch (Eom) followed the soil-specific relation Eom/Eo= a e(bRes+cEo), where Res is residue rate t/ha and a, b and c are constants; Eo, is expressed in mm/d. In an effort to model the total evaporation (CE) during the energy-limited stage ‘U’ was obtained from appropriate CE versus time curves and (CE-U) was regressed over (t - ti)0.5 to obtain the slope ‘α’ (Ritchie 1972) for the soil-limited evaporation stage. The observed ‘U’ was independent of mulch rate and Eo but was strongly affected by soil type, Values of ‘α’ decreased with increase in mulch rate and decrease in Eo and coarseness of soil.The otherwise short lived benefit of evaporation reduction with mulch per se, which peaked after a few days was maintained when residue was mixed with soil at the stage when evaporation reduction reached a maximum; this benefit continued for several weeks. Cumulative evaporation values computed from ‘U’ and ‘α’ agreed closely with the observed values under straw mulch for loamy sand and clay loam soils and for ‘undercut’ and ‘residue mixed’ treatments on all soils regardless of Eo, and for all situations under small Eo. However, for sandy loam and silt loam soils under Eo of 10 mm/d, the modified square root of the time function of Jalota et al. (1988) gave a better fit.

Notizen: Abstract. Soil microstructures and biological activity were studied in thin sections of Culluna heathland soils subject to periodic burning. Freely drained Brown Podzolic soils from a species-rich heath at Dinnet Muir, Aberdeenshire, Scotland were compared with shallow Humo-ferric Podzols with a thick humus layer (5–10 cm) supporting a species-poor heath at Balmenach, Aberdeenshire.Structures with greater porosity occurred in all Dinnet soils and the most recently burned Balmenach soil. Burning led to an increase in soil porosity which gradually disappeared after a period of 2–3 years. Soils of the recently burned site had more enchytraeid worms than those burned ten years previously. Most of the Dinnet soil samples were dominated by extremely fine granular structure which could have been produced by flocculation of well decomposed organic matter or by enchytraeid worms. In recently burned sites the increase in soil macro- and microbial activities may lead to the formation of composite structures.Regular burning every 10–15 years has been the land management practice in Scottish heathlands to ensure the production of fresh browse of nutritious heather shoots for herbivores. The near-ground microclimate and regeneration mechanisms of heathland plants are well adjusted to the periodic disturbance by fire. We found that the gradual decrease in surface soil porosity over time can be restored by prescribed burning. Soil structure and the distribution and continuity of pores in the soil profile directly affect soil water movement and retention. These factors have important ecological implications for post-fire vegetation recovery.

Notizen: Abstract. Simulated estimates of crop yield were made for rainfed rice in a 50 ha dryland rice area. The aim was to investigate how soil units and management units of different sizes with different yields could be used to obtain values for areas of land. Two procedures were applied. First, yields were simulated at six sites, that were representative of six soil mapping units. Second, yields were simulated using soil information from 133 auger sites, and were interpolated over management units using block kriging. Differences between the two procedures for the total area and for a test set of 22 additionally sampled locations were small. A 60% increase in precision was achieved when relatively large management units were defined.A Geographical Information System was used to identify areas with greatest yield potential for rainfed dryland rice. Statistical analysis showed that the six soil units could be grouped into three yield classes. The largest yields were obtained for a sub-area comprising 11% of the survey area which was associated with a slowly permeable Bg horizon in the soil profile.It was concluded that the best procedure for the spatial interpolation of simulated rice yield should be based on preliminary simulation of crop yields. A sensitivity analysis of the impact of weather variability and soil heterogeneity on the variation of yield was useful to detect the importance of their contributions. The procedures developed in this study are of value in obtaining a reliable estimate of average yield, and can consequently be used for associated cost-benefit calculations.

Notizen: Book reviews in this article: Soil Conservation and Silviculture By J. Dvořák & L. Novák (editors). Translated by V. Sochor. Environmental Soil Biology – 2nd Edition By M. Wood.

Notizen: Abstract. Soil profiles, first sampled between 1963 and 1973, were resampled in 1991 in an upland area with modertely high deposition of pollutants. One hundred horizons from 32 profiles, representing 10 different soil subgroups were analysed for pH and seven variables related to pH, using the same laboratory methods on both sampling occasions. To allow comparisons to be made with results obtained with these old methods, analysis of the 1991 samples was repeated for some determinands using the methods currently used in the analytical laboratory. Organic and A horizons show a consistent increase in acidity between samplings. Although brown soils and lithomorphic soils have increased in acidity throughout their depth, gleys and podzols have decreased in acidity at depth, probably because of poor water transmission downwards into these horizons. Correlations with other determinands suggest that the dominant process in the soils is leaching of basic cations and their replacement on exchange sites by protons and probably aluminium ions. A cause of the increase in soil acidity is likely to be the deposition of atmospherically transported pollutants.

Notizen: Abstract. Currently there is growing interest in the restoration of drained peatlands in Britain. In order to investigate some of the effects of changes in land management practices on the biogeochemistry of peatlands, a field experiment was designed to manipulate the hydrological conditions in a naturally drained acid gully mire in Mid-Wales. We report preliminary results of the effects of experimentally rewetting the mire on the hydrochemistry of bromide in the peat-water. Results show that rewetting had a dramatic effect on the concentrations of bromide, which increased substantially. Peak values approached 1 mg/dm3 in some samples following rewetting, compared with typical values 〈 0.05 mg/dm3 under the drained conditions. Bromide was positively and significantly correlated with Dissolved Organic Carbon (DOC) in the peat-water, which suggests that Br- is derived from breakdown of organic matter in the reducing conditions following rewetting. The bromide mobilized by rewetting may be leached out of the system and/or re-assimilated by the wetland vegetation. Further monitoring is needed to determine whether the observed hydrochemical response of bromide to rewetting of the mire has any longer-term effects.

Notizen: Abstract. Monoculture winter barley was grown for 5 years with 80 or 160 kg/ha of fertilizer nitrogen (N) and established by either shallow cultivation (straw removed) or ploughing (straw incorporated) in a replicated 2 ± 2 split plot experiment. The lower N rate reduced average grain yield from 6.85 t/ha to 5.61 t/ha. The cultivation/straw disposal system had no effect on yield. Halving the N rate reduced the amount of N removed in the crop by an average of 40 kg/ha and reduced the amount of nitrogen leached by 11 kg/ha per year. Using a shallow cultivation system for crop establishment, following the removal of straw, initially reduced N leaching compared to ploughing in the straw, but in the later years of the experiment losses were similar. Over the five years the full N rate with ploughing system resulted in a small positive nitrogen balance of 66 kg/ha, but all other treatment combinations resulted in a negative balance.

Notizen: Nine different techniques were used to record the initial change in the physical and hydrological properties of a freshly tilled soil surface following successive cycles of wetting and drying. The study was made in the field on a sandy clay loam soil ploughed and harrowed and then exposed to three simulated rainfall events of 76 mm/h for 15 minutes. Although the degradation of the soil surface increased with each successive rainfall, the most significant changes were observed after the first rainfall. Qualitative observations of clod size distribution and crust development provide a good indication of the early stages of soil surface degradation. Complementary physical data were quickly obtained using a hand held shear vane. These techniques are simple and robust enough that they can be used in on-farm research programmes, where resources, both human and technical are at a premium. Tension infiltrometry provided hydrological information that complemented the physical information provided by the above techniques, but is not as simple.

Notizen: Abstract. To study the change in soil organic carbon (SOC) since it was recorded during the Belgian National Soil Survey some 40 years ago, we recently revisited 939 locations still under use as arable land. The study area comprised almost the entire province of West Flanders (about 3000 km2) characterized by profound changes in its arable land management.Taking the increased ploughing depth (by 9.8 cm on average) into account, a significant (P= 0.001) increase of the SOC content by 0.2% on average was found. Expressed as an amount, the SOC in the topsoil rose by 9.3 t/ha on average, representing an increase of 25%. This is comparable with the conversion of arable land into grassland for 2 to 3 decades.Geostatistical tools were used to map the SOC at the two times of observation. These showed that most of the spatial variation occurred within about 4 km. Since the community level is the smallest spatial resolution on which agricultural statistics are gathered officially, a detailed modelling of the change in SOC was impossible. However, by selecting communities with extreme changes in SOC, we found indications that the major source of increase in SOC was due to the large increase in pig breeding.

Notizen: Abstract. The understanding of nitrogen mineralization is central to providing good advice to ensure that nitrogen (N), from whatever source, is utilized by crops as efficiently as possible to minimize pollution. We have reviewed how mineralization is accounted for in current advice. It is clear that there is at least a qualitative understanding of the effects of soil and crop management on N mineralization and N supply, which has enabled the development of Codes of Good Agricultural Practice and fertilizer recommendations systems, based on sound scientific principles. However, to refine advice there is a need for a better quantitative understanding.Although soil organic matter (SOM) is a major source of N for crops, we are unable adequately to predict fertilizer requirement as affected by mineralization of SOM. Nitrogen returns from crop residues can vary considerably between fields; the provision of better field specific advice is restricted by our inability accurately to quantify this variability. The qualitative controls on the amount and timing of N release from ploughed grass are known, but better quantification of mineralization/immobilization over both the short- and long-term and better understanding of the relationship with sward age, inputs and management are essential. Much N can also be released from pasture and lost to the environment, especially where long-term leys have been grazed and there is a need to quantify the changing balance of mineralization and immobilization with the age of sward and N input. Whilst the overall principle of cultivation affecting mineralization is well known and appreciated, little is known about the mechanisms and quantification is only possible for a comparison of such extremes as ploughing and direct drilling.

Notizen: Book Review in this ArticlesSoil Conservation (Third Edition) By N. Hudson.Conserving soil resources: European perspectives. Selected papers from the First International Congress of the European Society for Soil Conservation Edited by R.J. Rickson.Soil and water management systems, 4th edition By G.O. Schwab, D.D. Fangmeier & W.J. Elliot.

Notizen: Abstract. In response to the European Community Nitrate Directive (91/676) a catchment scale Geographical Information System (GIS) model of nitrate leaching has been developed to map nitrate vulnerability and predict average weekly fluxes of nitrate from agricultural land units to surface water. This paper presents a pilot study which investigated the spatial variability of soil nitrates in order to: (1) define an appropriate pixel size for modelling N leaching; (2) quantify the within-unit variability of soil nitrate concentrations for pasture and arable fields; and (3) assist in the design of an efficient sampling strategy for estimating mean nitrate concentrations. Soil samples, taken from two 800 m transects in early September 1994, were analysed for water soluble nitrate. The arable soils had a mean nitrate-nitrogen concentration of 0.693 μg/g (S.E. 0.054 μg/g) and the pasture soils had a higher mean nitrate-nitrogen concentration of 0.86 μg/g (S.E. 0.085 μg/g). Spatial variability was investigated using variograms. The pasture data had a weak spatial relationship, whereas the arable data exhibited a strong spatial relationship which fitted a spherical variogram model (r2 0.87), with a range of 40 m. A pixel size of 40 m is suggested for nitrate modelling within the GIS based on the arable variogram and an improved sampling strategy for model validation is suggested, involving bulking sub-samples over a 40 m grid for estimating mean nitrate concentrations in combined land use and soil units.

Notizen: Abstract. An area of about 24 km2 in arable East Lothian, Scotland, was examined for soil erosion by water following a severe rainstorm in October 1990. Significant erosion was found in only 10 fields out of 26.5 in an area where topography, soils and cropping suggest a high erosion risk. Doubt is cast on some assessments of the widespread risk of significant soil erosion by water in arable areas of the UK.

Notizen: Abstract. Proposed restrictions on the disposal of sewage to the marine environment means that alternative land based outlets are required in the UK. Commercial forestry represents a significant land use that could receive and benefit from the application of sewage sludge, to overcome the generally poor soil nutrient status. The oligotrophic and sensitive nature of surface waters in many afforested areas requires that the environmental consequences of the widespread use of organic fertilizers in forestry are carefully considered. This paper compares the effects of an N and P fertilizer with that of sewage sludge on the nutrient content of foliage in a pole stage Scots pine (Pinus sylvestris) forest and of nutrient fluxes in soil. Both conventional fertilizer and sewage treatments had significant but differing effects on the availability and leaching of the major nutrients, especially N and P. Evidence for increased nitrification and nitrate production with time was apparent for both treatments. Fluxes of N and P in mineral horizon leachate were consistently smaller than those from the overlying organic horizon. Foliar nutrient concentrations after one year were significantly higher (P 〈 0.01) in all of the treatments, and conventional fertilization with urea produced a significantly higher foliar N concentration than that measured in the sludge-treated plots. There was no evidence for appreciable N or P leaching from the site within a year of sludge application.

Notizen: Abstract. An easy-to-use simulation model was developed with the aim of improving fertilizer practice when crop residues are incorporated instead of removed. It was tested against data from a well-monitored N fertilizer experiment in which three successive brassica crops were grown followed by barley.Experimental findings included: (a) that fertilizer-N greatly increased yield of 3 crops without increasing residual soil mineral-N at harvest unless supply exceeded crop demand; (b) that, by contrast, fertilizer-N increased both yield of and residual soil mineral-N left by the remaining crop throughout the range of applications; and (c) that at each harvest the apparent disappearance of fertilizer-N by immobilization and other processes was almost proportional to fertilizer-N. These phenomena were simulated by the model.Overall the model gave estimates of soil mineral-N, plant weight and % N in the crop for each crop that were either in close agreement with or linearly related to the measured values. Deviations from this pattern are shown to result almost entirely from experimental error. In addition the model gave simulations of the time course of soil mineral-N and soil water that were in good agreement with measurement.Simulations with the model indicate that appreciable benefits from residue incorporation of crops will only be obtained when fertilizer-N is also applied, unless plant masses at harvest are small.

Notizen: Abstract. The MACROS crop model was evaluated for its utility to generate information on land suitability for dry season peanut cropping based on water availability at the regional scale in Khon Kaen Province, Northeast Thailand. The model was specific for the condition where crop growth is limited by water stress, and evaluated using both calibration and validation phases in sequence. In the model calibration, data sets from one peanut field experiment were used to calibrate some parameters to obtain the best agreement between experimental and simulated results. The model validation, in this study, consisted of a ‘validation A’, with emphasis on the accuracy and a ‘validation B’, with emphasis on the usefulness and relevance of the model. In the model validation A, data sets from peanut field experiments were used to validate the model under different conditions. Satisfactory agreements were found between the dynamics of observed and corresponding simulated values of shoot dry weight in every condition involved in this validation study. Also the simulated pod yields agree well with the field data. For the validation R, the model was further validated using data from 36 farm trials conducted at 5 different test sites. A high positive correlation (r= 0.91) existed between observed and simulated pod yields. Because of these satisfactory agreements between observed and corresponding simulated values, it was concluded that the model is valid and can be applied to Khon Kaen Province.

Notizen: Book reviews in this article: Soils and Environment By S. Ellis & A. Mellor. Soil Erosion Research Methods Edited by R. Lal. Agriculture and Environment: Bridging Food Production and Environmental Protection in Developing Countries Edited by Anthony S.R. Juo and Russell D. Freed. Soil Management in Sustainable Agriculture Edited by H.F. Cook and H.C. Lee. Soil Nutrient Bioavailability—2nd Edition By Stanley A. Barber. Soil fertility decline under sisal cultivation in Tanzania By Alfred E. Hartemink.

Notizen: Abstract. Information about the soil fertility status in irrigated ricelands at regional scales (1:50 000–1:250 000) is commonly not contained in classical soil maps. To assess the agronomic suitability of two different reconnaissance soil maps, we conducted a detailed soil survey in the Nueva Ecija province, Philippines. Soil samples were collected from 384 farmers' fields, and soil properties were measured for topsoil and subsoil samples. For most soil properties, a soil map made in 1940 (1:125 000) had within-map unit variances that were smaller than the total variance, whereas a new soil map of 1992 (1:50 000) did not significantly reduce the within-class variance. In both soil maps, classification into mapping units accounted for 0–40% of the variance of 14 agronomically important soil properties and large within-map unit variabilities were found. Underlying strategies of classical soil survey supported the partition of variance for relatively stable soil properties, such as soil texture, CEC, and organic matter. If reconnaissance soil maps are used in quantitative land evaluation studies, existing maps require upgrading by adding quantitative information about relevant soil properties and their within-map unit variability The sampling demand for upgrading a reconnaissance soil map was large, but pedotransfer functions can be used as cost-saving tools. Measures of soil nutrient status were highly variable within all mapping units and differences among farmers were much greater than the differences between soil types. Therefore, nutrient management in the study region should be based on individual field or farm recommendations rather than on soil-map based recommendations.

Notizen: Abstract. The spatial distribution of agricultural grassland in England and Wales has been assessed using a land evaluation model applied to information describing soils, climate and topography on a 5 × 5 km grid. The model calculates land suitability for grassland from assessments of trafficability/poaching risk and yield class. The spatial distribution of agricultural grassland was modelled for a 30 year climatic baseline (1941–1970) and for incremental changes in temperature and proportional changes in precipitation relative to that baseline.Model estimates for the current distribution of grassland suitability agree well with observed data of actual grassland distribution. The best suited land occurs in south west England, Wales, the Welsh borders and Cheshire with fragmented areas of well suited land in north west England and on the Pens and Humberhead levels.The climatic sensitivity analysis suggests that grassland production in England and Wales is resilient to small perturbations in mean temperature (up to +2°C) and precipitation (±10%). The effect of increasing temperature by 1°C is almost completely offset by precipitation increases of 10% resulting in little change to the distribution of grassland suitability. However, greater temperature changes (+ 4°C) have a major influence on the ability of land to support intensively managed grassland because of increased drought stress. Results indicate that a change in the climate comparable with current best estimates for the future would benefit grassland on good quality land at higher altitudes.

Notizen: Few economic relationships have been as scrutinized as that between SNA measures of national product, investment and consumption, and welfare. The present paper contrasts SNA economic production and welfare to total production and welfare within the Walrasian framework of usefulness and costliness. An evaluation of deductions and additions to the SNA made by Nordhaus-Tobin, Zolotas, Richard and Nancy Ruggles, Kendrick, Eisner and Jorgenson-Fraumeni, in their research on extended product and income accounts and improved indicators of welfare reveals numerous unresolved analytical and measurement issues; and reaffirms the usefulness of the SNA as a fundamental, initial, welfare indicator.

Notizen: Data from the International Comparison Programme (ICP) generate a number of analyses examining price and quantity relationships across countries. Although geographic location is sometimes evoked to explain differences across observations, it is seldom used to measure the extent of this interrelationship. Using ICP Phase V benchmark studies (Summers and Heston, 1991) at the level of household consumption for approximately 64 countries and 23 aggregate headings in 1985, this paper introduces such a measure, testing for spatial autocorrelation among price relatives with respect to three different measures of relative location: the pairwise existence of a common boundary, the distance between capital cities and the amount of trade between two countries.

Notizen: This paper examines issues involved in calculating a value added index in order to measure real value added at the industry level. Three methods of calculating real value added are considered; the Laspeyres double-deflation method recommended by the United Nations System of Nation Accounts, the commonly used single-deflation method, and the double-deflation Divisia method. Actual data are employed to clarify and illustrate the issues involved, and the paper concludes with a recommendation for an appropriate index to use when calculating industry real value added.

Notizen: The National Accounting Matrix including Environmental Accounts (NAMEA) shows environmental burdens that are consistent with the economic figures in the national accounts. In the NAMEA, the existing national accounts matrix has been extended with accounts in physical units. On the basis of the expected contribution of each polluting substance to a particular environmental problem, emissions are converted to theme equivalents. This results in six summary environmental indicators that are directly comparable to the conventional economic aggregates. In addition, this meso-level information system can be used as the core data framework for integrated analyses and forecasts of economic and environmental changes.

Notizen: This paper analyzes how inequality in Before and After Government income has changed in Germany since reunification using the 1990 through 1992 waves of the German Socio-Economic Panel. A Theil decomposable inequality index is used to measure inequality in Germany and in its eastern and western states. Massive public transfers from west to east have narrowed the east-west income gap, substantially offset the rise in income inequality from private sources, and lowered overall inequality in the western states. The net result of this policy has been a drop in After Government income inequality in Germany between 1990 and 1992.

Notizen: The paper concerns the links between labour force accounts and national accounts. It first discusses the variation in the perception of labour force among countries which results in much disparity in recorded participation rates. This obviously makes international comparison difficult. Since benchmark labour force information is often tied to population censuses which are infrequent and vary in concepts and approaches, even comparisons within a country over time are difficult. Finally a discussion of the use of labour force data to estimate the unrecorded economy is followed by suggestions on the direction for future work.

Notizen: Four alternative measures of the average duration of unemployment are examined with the intention of illustrating: (1) the biases inherent in the average incomplete duration of unemployment, a statistic that is often the only one reported by many statistical agencies; and (2) the robustness of the average complete duration of unemployment to a host of assumptions underlying its derivation by non-parametric methods. Canadian data are employed, but the results offer a guide to the construction of the average complete duration of unemployment that may have broader applications.

Notizen: The transformation of a non-market to a market economy ought to change fundamentally the significance of money incomes for welfare. Whereas in a stressful non-market economy such as the former Soviet Union, non-monetized resources could substitute for money income and promote welfare, in a modern market economy money income should be a good proxy for household welfare. This article tests the extent to which Russians are now in a modern market economy by analyzing data from nationwide Russian surveys in January, 1992, and April, 1994. Modern influences are increasingly important as a determinant of the distribution of money incomes, but not as an influence upon household welfare. The “randomness” of temporary disruptions of welfare is in accord with Rawlsian principles of equity.

Notizen: We consider the distributional consequences at a national level in Russia during the initial phase of market reforms between the mid-1980s and the early 1990s. Although the incomes of many individuals changed favourably under the reforms during this period, average real household per capita income declined between 1985 and 1992. In particular during the first year of major reform in 1992 households at the lower end of the income distribution seemed to incur the largest fall in income. As a consequence there was a rise in measured income inequality. The Gini coefficient, estimated by various researchers to have been around 27 percent between the late 1960s and early 1990s. we estimate to have increased to 32.2 percent by the end of 1992. We also estimate that poverty increased with 18.5 percent of the population on incomes lying below the official subsistence level at the end of 1992.

Notizen: Prices of food vary greatly among the developed countries, and some countries' food prices have been consistently far above the OECD average. The main explanation for food price difference is the extent of protection of agricultural products at the farm level. A second important influence is the level of VAT on food. A third is deviations of aggregate country price levels from the levels that would be predicted from their per capita incomes, presumably because of omitted characteristics of the countries' economies, such as, possibly, inefficient or monopolistic service sectors. In addition, there are occasional episodes of high or low price levels due to temporary factors affecting exchange rates.The degree of protection of agricultural products is treated both as an exogenous factor and as an endogenous one. In the latter case, it is explained by climatic conditions and, presumably, the political influence of the agricultural sector or a general desire to retain an agricultural sector despite poor growing conditions.

Notizen: Measures of national product can be misleading because there is nonmarket production. There are also distortions due to transactional activities, which are expenditures to support transactions, not actual output consumed. For 1950–89, this study recalculates output for the United States, adjusting for transactional activities and nonmarket production. Due to relatively rapid growth in transactional activities, GNP overstates output growth in the 1950s; because there was slow expansion of transactional activities in the early 1970s, GNP understates actual output. Since 1974, increases in transactional activities and shifts to market production lead GNP to exaggerate improvement of “actual” output per capita.

Notizen: The paper examines Puerto Rican trends in income distribution during the 1970s and 1980s, then attempts to ascertain the source of the changes in income inequality through a decomposition of the Gini coefficient by factor income source. The study finds that poverty and inequality declined unambiguously during the twenty-year period. The source of the fall in income concentration was found to have been tied, not to changes in the distribution or share of earned income, but to that of unearned income, particularly transfers. These appear to have also accounted for the decline in poverty.

Notizen: The hypothesis that the demand for services is income-elastic tended to find support in early empirical work. Recent studies however, adopting improved methodologies and better international data (based on PPP exchange rates), have challenged this conventional wisdom. Using an updated, disaggregated dataset covering 60 countries in 1980 this paper re-estimates income and price elasticities of demand for services. It rejects the income-elastic argument overall but confirms a wide range of income elasticity estimates (above and below unity) across different types of services. Estimates are also shown to be sensitive to the a priori model of service demand.

Notizen: Most empirical studies of poverty assume an equal sharing of resources between all household members. There is a growing body of research indicating that this assumption is not realistic. This paper explores how the unequal sharing of resources could potentially affect the measurement of poverty. Simulations based on micro-data from two countries (Italy and the U.S.A.) are carried out under the assumption that women “lose” and men and children “gain” because of unequal sharing in the household. Our findings suggest that if there is significant intra-household inequality of this type, as some writers have suggested, then conventional methods of poverty measurement will likely to lead to a serious under-estimate (over-estimate) of the incidence and intensity of female (male) poverty.

Notizen: This paper presents multilateral comparisons of output, productivity and purchasing power parities in manufacturing, for 1975 and 1987. Two multilateral approaches are considered, namely the Geary–Khamis method and the generalized Theil–Törnqvist method based on the EKS procedure. The paper discusses the problem of lack of additive consistency of the generalized Theil–Törnqvist index and the absence of constant price comparisons within this framework. Some procedures that lead to near additive consistency are proposed. The empirical results show that multilateralization does not substantially affect the results and that both the Geary–Khamis and the generalized Theil–Törnqvist index give results comparable to the binary comparisons.