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1

Electronic Resource

Cattle and Weedy Shrubs as Restoration Tools of Tropical Montane Rainforest (2000)

Posada, Juan M. ; Aide, T. Mitchell ; Cavelier, Jaime

Boston, MA, USA : Blackwell Science Inc

Restoration ecology 8 (2000), S. 0

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ISSN: 1526-100X

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: Over the last 150 years, a large proportion of forests in Latin America have been converted to pastures. When these pastures are abandoned, grasses may slow re-establishment of woody species and limit forest regeneration. In this study, we explored the use of cattle in facilitating the establishment of woody vegetation in Colombian montane pastures, dominated by the African grasses Pennisetum clandestinum (Kikuyo) and Melinis minutiflora (Yaraguá). First, we described woody and herbaceous vegetation in grazed and non-grazed pastures. Second, we tested the effect of grazing and seed addition on the establishment and growth of woody species. We also determined if the effect of grazing was different in P. clandestinum and M. minutiflora pastures. We found that low stocking density of cattle greatly increased density, number of branches per individual (a measure of “shrubiness”), and basal area of woody species, but also reduced woody plant species richness and diversity. In the grazed area, the shrubs Baccharis latifolia (Chilca) and Salvia sp. (Salvia) were the most abundant. The combined effect of grazing and shading from the shrubs reduced herbaceous vegetation by 52 to 92%. In the grazing/seed addition experiment, grazing increased establishment of woody seedlings, particularly of the shrub Verbesina arborea (camargo), but the largest effect was seed addition. Where grasses are an important barrier to regeneration, grazing can facilitate the establishment of shrubs that create a microhabitat more suitable for the establishment of montane forest tree species.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1046/j.1526-100x.2000.80052.x

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2

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Barriers to Lowland Tropical Forest Restoration in the Sierra Nevada de Santa Marta, Colombia (1994)

Aide, T. Mitchell ; Cavelier, Jaime

Oxford, UK : Blackwell Publishing Ltd

Restoration ecology 2 (1994), S. 0

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ISSN: 1526-100X

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: Extensive areas of the tropics have been converted into pasture for cattle ranching. Frequently, abandoned pasture does not revert to forest. The goal of this project was to identify barriers to lowland moist forest regeneration in highly degraded grasslands in the Sierra Nevada de Santa Marta, Colombia. The barriers we considered were seed source, seed predation, competition with grasses, microclimate and soil limitations on plant growth, and fire. Seed dispersal into the grasslands is limited to within 10 meters of forest fragments, but this barrier can be overcome by sowing seeds and planting seedlings and by establishing perches to attract dispersers. In these degraded grasslands, seed predation was lower than in the adjacent forest patches, and there was no evidence that grasses inhibited the establishment of woody species. The most important barrier was the severe degradation of the soils. In much of the area, the A and B horizons have been eroded away, leaving saprolite at the soil surface. Seedlings of two fast-growing pioneer species, Ochroma pyramidale and Cochlospermum vitifolium, grew to a maximum height of only 2.5 and 12 cm, respectively, during the first eight months. The slow plant growth in the degraded grassland soils compared to forest soils was associated with lower levels of cation-exchange capacity, calcium, magnesium, and potassium. Even if these barriers could be overcome, the frequent and extensive use of fire in the region must be controlled to avoid killing established woody plants.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1526-100X.1994.tb00054.x

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3

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Regulation of water flux through trunks, branches, and leaves in trees of a lowland tropical forest (1998)

Andrade, José Luis ; Meinzer, Frederick C. ; Goldstein, Guillermo ; [et al.]

Springer

Oecologia 115 (1998), S. 463-471

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ISSN: 1432-1939

Keywords: Key words Hydraulic conductance ; Sap flow ; Stomata ; Transpiration ; Tropical forest trees

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract We studied regulation of whole-tree water use in individuals of five diverse canopy tree species growing in a Panamanian seasonal forest. A construction crane equipped with a gondola was used to access the upper crowns and points along the branches and trunks of the study trees for making concurrent measurements of sap flow at the whole-tree and branch levels, and vapor phase conductances and water status at the leaf level. These measurements were integrated to assess physiological regulation of water use from the whole-tree to the single-leaf scale. Whole-tree water use ranged from 379 kg day−1 in a 35 m-tall Anacardium excelsum tree to 46 kg day−1 in an 18 m-tall Cecropia longipes tree. The dependence of whole-tree and branch sap velocity and sap flow on sapwood area was essentially identical in the five trees studied. However, large differences in transpiration per unit leaf area (E) among individuals and among branches on the same individual were observed. These differences were substantially reduced when E was normalized by the corresponding branch leaf area:sapwood area ratio (LA/SA). Variation in stomatal conductance (g s) and crown conductance (g c), a total vapor phase conductance that includes stomatal and boundary layer components, was closely associated with variation in the leaf area-specific total hydraulic conductance of the soil/leaf pathway (G t). Vapor phase conductance in all five trees responded similarly to variation in G t. Large diurnal variations in G t were associated with diurnal variation in exchange of water between the transpiration stream and internal stem storage compartments. Differences in stomatal regulation of transpiration on a leaf area basis appeared to be governed largely by tree size and hydraulic architectural features rather than physiological differences in the responsiveness of stomata. We suggest that reliance on measurements gathered at a single scale or inadequate range of scale may result in misleading conclusions concerning physiological differences in regulation of transpiration.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s004420050542

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4

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Partitioning of soil water among canopy trees in a seasonally dry tropical forest (1999)

Meinzer, F. C. ; Andrade, José Luis ; Goldstein, Guillermo ; [et al.]

Springer

Oecologia 121 (1999), S. 293-301

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ISSN: 1432-1939

Keywords: Key words Roots ; Sap flow ; Leaf phenology ; Stable hydrogen isotope ratio ; Panama

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Little is known about partitioning of soil water resources in species-rich, seasonally dry tropical forests. We assessed spatial and temporal patterns of soil water utilization in several canopy tree species on Barro Colorado Island, Panama, during the 1997 dry season. Stable hydrogen isotope composition (δD) of xylem and soil water, soil volumetric water content (θv), and sap flow were measured concurrently. Evaporative fractionation near the soil surface caused soil water δD to decrease from about –15‰ at 0.1 m to –50 to –55‰ at 1.2 m depth. Groundwater sampled at the sources of nearby springs during this period yielded an average δD value of –60‰. θv increased sharply and nearly linearly with depth to 0.7 m, then increased more slowly between 0.7 and 1.05 m. Based on xylem δD values, water uptake in some individual plants appeared to be restricted largely to the upper 20 cm of the soil profile where θv dropped below 20% during the dry season. In contrast, other individuals appeared to have access to water at depths greater than 1 m where θv remained above 45% throughout the dry season. The depths of water sources for trees with intermediate xylem δD values were less certain because variation in soil water δD between 20 and 70 cm was relatively small. Xylem water δD was also strongly dependent on tree size (diameter at breast height), with smaller trees appearing to preferentially tap deeper sources of soil water than larger trees. This relationship appeared to be species independent. Trees able to exploit progressively deeper sources of soil water during the dry season, as indicated by increasingly negative xylem δD values, were also able to maintain constant or even increase rates of water use. Seasonal courses of water use and soil water partitioning were associated with leaf phenology. Species with the smallest seasonal variability in leaf fall were also able to tap increasingly deep sources of soil water as the dry season progressed. Comparison of xylem, soil, and groundwater δD values thus pointed to spatial and temporal partitioning of water resources among several tropical forest canopy tree species during the dry season.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s004420050931

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5

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Tissue water relations in elfin cloud forest tree species of Serrania de Macuira, Guajira, Colombia (1990)

Cavelier, Jaime

Springer

Trees 4 (1990), S. 155-163

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ISSN: 1432-2285

Keywords: Water relations ; Conductance ; Water potential ; Tropical trees ; Turgor pressure

Source: Springer Online Journal Archives 1860-2000

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

Notes: Summary Diurnal courses of stomatal conductance, leaf water potential, and the components of tissue water potential were measured in six canopy species in an elfin cloud forest. High values of stomatal conductance were measured on cloudy days and during early morning and late afternoon of sunny days. Decreases in stomatal conductance with increases in vapour pressure deficit may have been a response to avoid further water deficits and suggested a stomatal response to changes in relative humidity. Daily transpiration varied between 470 and 1014 g m-2 day-1 during cloudy days and between 532 and 944 g m-2 day-1 during clear days. Stomatal conductance may have also responded to changes in leaf water potential, which was minimum at noon. The minimum tissue water potential measured in the field was -1.8 MPa in Myrcianthes fragrans, and the minimum turgor pressure was 0.49 MPa also in M. fragrans. There was a correlation between the osmotic potential and the minimum tissue water potential, suggesting that osmotic potential plays a major role in the maintenance of turgor in these species, in spite of the great variability in the elastic properties of leaf tissues. Turgor pressure decreased during the day following the course of water potential but never approached the turgor loss point, as it has been measured in some lowland rain forest trees. This is a strong indication that elfin cloud forest trees do not suffer severe water deficits, and that small tree stature is not directly related to water shortage.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00225780

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6

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Fine-root biomass and soil properties in a semideciduous and a lower montane rain forest in Panama (1992)

Cavelier, Jaime

Springer

Plant and soil 142 (1992), S. 187-201

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ISSN: 1573-5036

Keywords: cloud forest ; fine-roots ; Panama ; soil profile ; root-biomass ; semideciduous-forest ; soil cores ; tropical forests

Source: Springer Online Journal Archives 1860-2000

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

Notes: Abstract The distribution of root biomass and physical and chemical properties of the soils were studied in a semideciduous and in a lower montane rain forest in Panama. Roots and soil samples were taken by means of soil cores (25 cm deep) and divided into five, 5-cm deep sections. Soils were wet-sieved to retrieve the roots that were classified in four diameter classes: very fine roots (〈1 mm), fine roots (1–2 mm), medium roots (2–5 mm) and coarse roots (5–50 mm). Soil samples were analyzed for organic carbon, total nitrogen, available phosphorus, exchangeable bases, cation exchange capacity, pH, aluminium and exchangeable acidity. Total root biomass measured with the soil corer (roots 〈50 mm in diameter) was not different between the forests (9.45 t ha-1), while biomass of very fine roots was larger in the mountains (2.00 t ha-1) than in the lowlands (1.44 t ha-1). The soils in the semideciduous forest were low in available phosphorus, while in the mountains, soils had low pH, high exchangeable aluminium and exchangeable acidity, and low concentration of exchangeable bases. Phosphorus was in high concentration only in the first 5 cm of the soil. In both forests, there was an exponential reduction of root biomass with increasing depth, and most of the variation in the vertical distribution of roots less than 2 mm in diameter was explained by the concentration of nitrogen in the soils. The results of this study support the hypothesis that a large root biomass in montane forests is related to nutrients in low concentration and diluted in organic soils with high CEC and low bulk density, and that fine root biomass in tropical forests in inversely related to calcium availability but not a phosphorus as has been suggested for other forests.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00010965

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Effects of irrigation on litterfall, fine root biomass and production in a semideciduous lowland forest in Panama (1999)

Cavelier, Jaime ; Wright, S. Joseph ; Santamaría, Johanna

Springer

Plant and soil 211 (1999), S. 207-213

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ISSN: 1573-5036

Keywords: below ground- productivity ; biomass ; fine roots ; irrigation ; litterfall ; lowland forest

Source: Springer Online Journal Archives 1860-2000

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

Notes: Abstract The effects of irrigation on fine root biomass, root production and litterfall were measured at the community level, in a semideciduous lowland forest in Panama. Biomass of roots less than 2 mm in dia. in the first 10 cm of the soil (measured with soil cores), was higher in irrigated (1.80 Mg ha-1) than in non-irrigated plots (1.24 Mg ha-1). During the dry season, productivity of roots (measured with ingrowth cylinders filled with root-free soil), was higher in irrigated (1.6 g m-2 day-1) than in control plots (0.3 g m-2 day-1). In control plots, root productivity was highly seasonal. Maximum root growth into the root-free soil, occurred during the transitions from dry to wet, and from wet to dry season, possibly as a response to water and/or nutrient pulses. Litterfall was not significantly different between irrigated (3.8 g m-2 day-1) and control plots (3.7 g m-2 day-1). The results of this study show that root-productivity is limited by the water supply during the dry season, and that water by itself, is not a limiting factor for community-level litter production.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1004686204235

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8

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The effect of abandoned plantations of Pinus patula and Cupressus lusitanica on soilsand regeneration of a tropical montane rain forest in Colombia (1998)

CAVELIER, JAIME ; TOBLER, ALEXANDRA

Springer

Biodiversity and conservation 7 (1998), S. 335-347

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ISSN: 1572-9710

Keywords: Pinus patula ; Cupressus lusitanica ; soils ; montane forests ; regeneration

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Species richness and diversity and soil physical and chemical properties were compared between a mature lower montane rain forest (LMRF) and abandoned 21-year-old plantations of introduced Pinus patula and Cupressus lusitanica in the central Andes of Colombia (2000m). In 0.1ha plots, species richness (number of species) and diversity (Shannon and Simpson indexes) were higher in the LMRF, followed by P. patula and C. lusitanica plantations. There were 56species and 30families of higher plants in the LMRF, 26species and 15families in the P. patula plantation, and 18species and 10families in the C. lusitanica plantation. There were no statistically significant differences (p〈0.05) in soil physical or chemical properties between P. patula, C. lusitanica and native LMRF. Nevertheless, soil carbon, the C/N ratio and total bases tended to be higher in the native forest than in the plantations. Available P tended to be higher in the P. patula plantation. These results show that, although abandoned plantations can support some native species, particularly in the understorey, species richness is far from that of the native forest.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1008829728564

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