ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

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Field bioassessments for selecting test systems to evaluate military training lands in tallgrass prairie. Ecosystem health. V (1990)

Schaeffer, D. J. ; Seastedt, T. R. ; Gibson, D. J. ; [et al.]

Springer

Environmental management 14 (1990), S. 81-93

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ISSN: 1432-1009

Keywords: Ecological test systems ; Physical stress ; Chemical stress ; Military training sites ; Prairie ; Ecosystem risk assessment

Source: Springer Online Journal Archives 1860-2000

Topics: Energy, Environment Protection, Nuclear Power Engineering

Notes: Abstract Ecosystem responses to physical or chemical stress may vary from changes in single organisms to alteration of the structure and function of the ecosystem. These responses to stress cannol be predicted exactly. Ecosystems repeatedly exposed to physical and/or chemical stress can be used to study the separate and combined environmental effects of stress. Such studies also allow the development of procedures to select test systems for the analysis of stress in ecosystems. A preliminary field survey of six military training sites at Fort Riley, Kansas, USA, was conducted to identify and verify ecological test systems for evaluating ecosystem responses to physical and/or chemical stress. Comparisons of these data with data collected concurrently from Konza Prairie Research Natural Area reference sites showed that soil microarthropods, some species of macroarthropods, small mammals, and native earthworm species were negatively affected by stress. In contrast, plant species diversity, plant foliage biomass, soil mycorrhizae, and many soil characteristics were within the boundaries of nominal variations observed on “pristine” Konza Prairie. Introduced European earthworms appeared to be positively affected by training activities. This study provided a test of systematic procedures to support impact analysis, ecological toxicology, and ecosystem risk assessments.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02394022

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2

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The Role of Microarthropods in Decomposition and Mineralization Processes (1984)

Seastedt, T R

Palo Alto, Calif. : Annual Reviews

Annual Review of Entomology 29 (1984), S. 25-46

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ISSN: 0066-4170

Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff

Topics: Biology

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1146/annurev.en.29.010184.000325

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3

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Effects of Soil Nitrogen Reduction on Nonnative Plants in Restored Grasslands (1999)

Morghan, K. J. Reever ; Seastedt, T. R.

Boston, MA, USA : Blackwell Science Inc

Restoration ecology 7 (1999), S. 0

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ISSN: 1526-100X

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: We studied the cumulative effects of 3 years of carbon amendments on previously disturbed mixed-grass prairie sites near Boulder, Colorado. Analysis of soil inorganic nitrogen during the third field season indicated statistically significant but short-term nitrogen reduction in response to addition of a combination of sugar and sawdust treatments. Plant foliage production was significantly reduced by these carbon amendments and averaged 377 g/m2/year on control plots versus 219 g/m2/year on treated plots. Undesirable species such as Centaurea diffusa (diffuse knapweed) exhibited a similar biomass response. But after three years of treatment there is little evidence to suggest a relative increase in desirable, reseeded species such as Agropyron smithii (western wheatgrass). We suggest that the carbon amendment treatment alone is an inadequate remediation technique in areas exposed to extensive seed rain by exotic species.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1046/j.1526-100X.1999.07106.x

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4

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Woody overstorey effects on soil carbon and nitrogen pools in South African savanna (2003)

Hudak, A. T. ; Wessman, C. A. ; Seastedt, T. R.

Oxford, UK : Blackwell Science Pty

Austral ecology 28 (2003), S. 0

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ISSN: 1442-9993

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: Abstract Woody plant encroachment in savannas may alter carbon (C) and nitrogen (N) pools over the long-term, which could have regional or global biogeochemical implications given the widespread encroachment observed in the vast savanna biome. Soil and litter %C and %N were surveyed across four soil types in two encroached, semi-arid savanna landscapes in northern South Africa. Litter at sampling points with a woody component had a higher %N and lower C : N ratio than litter at solely herbaceous points. Severely encroached areas had lower C : N ratios throughout the soil profile than less encroached areas. Soil %C and %N were highly influenced by soil texture but were also influenced by the presence of a woody overstorey, which increased surface soil %C on three soil types but decreased it on the most heavily encroached soil type. Soil C sequestration may initially increase with bush encroachment but then decline if bush densities become so high as to inhibit understorey grass growth.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1046/j.1442-9993.2003.01265.x

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5

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Controls of nitrogen limitation in tallgrass prairie (1991)

Seastedt, T. R. ; Briggs, J. M. ; Gibson, D. J.

Springer

Oecologia 87 (1991), S. 72-79

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ISSN: 1432-1939

Keywords: Andropogon gerardii ; Fire ; Nitrogen ; Prairie ; Productivity

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary The relationship between fire frequency and N limitation to foliage production in tallgrass prairie was studied with a series of fire and N addition experiments. Results indicated that fire history affected the magnitude of the vegetation response to fire and to N additions. Sites not burned for over 15 years averaged only a 9% increase in foliage biomass in response to N enrichment. In contrast, foliage production increased an average of 68% in response to N additions on annually burned sites, while infrequently burned sites, burned in the year of the study, averaged a 45% increase. These findings are consistent with reports indicating that reduced plant growth on unburned prairie is due to shading and lower soil temperatures, while foliage production on frequently burned areas is constrained by N availability. Infrequent burning of unfertilized prairie therefore results in a maximum production response in the year of burning relative to either annually burned or long-term unburned sites. Foliage biomass of tallgrass prairie is dominated by C4 grasses; however, forb species exhibited stronger production responses to nitrogen additions than did the grasses. After four years of annual N additions, forb biomass exceeded that of grass biomass on unburned plots, and grasses exhibited a negative response to fertilizer, probably due to competition from the forbs. The dominant C4 grasses may out-compete forbs under frequent fire conditions not only because they are better adapted to direct effects of burning, but because they can grow better under low available N regimes created by frequent fire.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00323782

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6

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Canopy interception of nitrogen in bulk precipitation by annually burned and unburned tallgrass prairie (1985)

Seastedt, T. R.

Springer

Oecologia 66 (1985), S. 88-92

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ISSN: 1432-1939

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary Nitrogen content of bulk precipitation and throughfall (canopy leachates) was measured on annually burned and unburned tallgrass prairie during a 20 month period. Throughfall amounts averaged 58% of precipitation on unburned prairie while throughfall on annually burned sites averaged 76% of precipitation inputs. Stemflow was measured in late summer and autumn. Volumes were correlated with stem density; maximum stemflow volumes measured in this study averaged about 50% of throughfall volumes. Bulk precipitation averaged 530, 456, and 420 μg/l of nitrate, ammonium and organic nitrogen, respectively. Throughfall on burned sites averaged 345, 344 and 980 μg/l of nitrate, ammonium and organic nitrogen, and throughfall on unburned sites averaged 258, 196 and 1701 μg/l of nitrate, ammonium and organic nitrogen. Microbes on standing dead vegetation and litter of the unburned sites were estimated to remove more inorganic nitrogen from bulk precipitation than did foliage on burned sites. Only a portion of the inorganic nitrogen in bulk precipitation is immediately available for plant use, and this availability is influenced by the amount of detritus present on the prairie.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00378557

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7

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Landscape patterns of litter decomposition in alpine tundra (1994)

O'Lear, H. A. ; Seastedt, T. R.

Springer

Oecologia 99 (1994), S. 95-101

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ISSN: 1432-1939

Keywords: Alpine ; Decomposition ; Landscape Litter ; Microarthropods

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract A two-year study of the decomposition of alpine avens (Acomastylis rossii) foliage in alpine tundra of the Front Range of Colorado demonstrated a strong landscape-mediated effect on decay rates. Litter on sites with intermediate amounts of snowpack decayed more rapidly than litter on sites with larger or smaller amounts of snow. Annual decay constants (k-values) of this foliage ranged from-0.33 in dry tundra to-0.52 in moist tundra to-0.47 in the wettest habitat. No site differences in mass loss of litter were detected until late winter-early spring of the first year of decomposition, when significantly faster decomposition was observed for litter beneath the snowpack. In spite of obvious landscape-related patterns in rates of litter decomposition, total microarthropod densities in the top 5 cm of soil did not differ among habitats. However, the relative abundance of the oribatid and prostigmatid mites did vary significantly across the landscape in relation to the moisture gradient. Oribatid mites comprised a greater proportion of total mites in wetter areas. Microarthropod densities and composition, as well as patterns of decomposition, were compared with previous alpine, as well as arctic tundra, studies. The effects of soil invertebrates on decomposition rates in the alpine were evaluated with a mushroom litterbag decomposition experiment. Naphthalene was used to exclude fauna from a subset of litterbags placed in mesic and xeric habitats. Mushrooms without naphthalene additions decayed significantly faster in the mesic sites. Densities of invertebrates were also greater on mushrooms in these mesic sites. Mushrooms placed in xeric sites generally lacked fauna. Thus, both the activities and the composition of the detritus-based food web appear to change substantially across the moisture gradient found in alpine tundra.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00317088

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8

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Soil invertebrate and plant responses to mowing and carbofuran application in a North American tallgrass prairie (1992)

Todd, T. C. ; James, S. W. ; Seastedt, T. R.

Springer

Plant and soil 144 (1992), S. 117-124

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ISSN: 1573-5036

Keywords: Andropogon gerardii ; earthworms ; macroarthropods ; nematodes ; Panicum virgatum ; primary production ; root detritus ; Sorghastrum nutans

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract Relationships between soil invertebrate populations and primary production of a tallgrass prairie were investigated using the insecticide-nematicide carbofuran and a range of mowing intensities to manipulate invertebrate densities and resource quantity and quality. The trophic composition of nematode populations was monitored through each of two growing seasons. Earthworm and macroarthropod densities and primary production were assessed at the end of the second season. Invertebrate densities were generally reduced in carbofuran-treated plots, although individual weights of surviving macroarth-ropod herbivores increased significantly (p〈0.05). Carbofuran failed to affect estimates of above- or belowground plant biomass after two years of treatment. Changes in resource quantity and quality resulted in rapid responses by dominant invertebrate consumer populations. A 28% reduction in live root mass and a 24% increase in root detritus following two years of mowing was associated with a 54% decrease in herbivorous nematode densities, a 47% increase in microbivorous nematode densities, and a 41% increase in native earthworm biomass.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00018852

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