The Experts below are selected from a list of 111453 Experts worldwide ranked by ideXlab platform
Hans Jacquemyn - One of the best experts on this subject based on the ideXlab platform.
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forest Edge Effects on the mycorrhizal communities of the dual mycorrhizal tree species alnus glutinosa l gaertn
Science of The Total Environment, 2019Co-Authors: Margaux Boeraeve, Olivier Honnay, Hans JacquemynAbstract:Abstract Forest conversion into agricultural land has resulted in a continuous decline in forest cover and in a reduced size and increased Edge-to-core ratio of the remaining fragments. Forest Edges are more directly exposed to sunlight, wind and pollutants and the resulting changes in habitat quality might have a large impact on plant and animal communities. Few studies, however, have focused on forest Edge Effects on mycorrhizal fungus communities. Here, we used high-throughput sequencing to study how communities of arbuscular mycorrhizal (AMF) and ectomycorrhizal fungi (EcMF), present in both the roots of the dual mycorrhizal tree Alnus glutinosa and in the soil, changed with increasing distance from the forest Edge within fragmented forests embedded in an intensively managed agricultural matrix. Overall, we found 158 AMF OTUs and 275 EcMF OTUs. Soil moisture content increased with increasing distance from the forest Edge, whereas soil nitrate concentration increased with increasing distance in south-facing and decreased in north-facing Edges. Distance to the forest Edge had a significant effect on EcMF community composition that largely overlapped with the observed changes in soil variables, especially soil moisture content. Apart from this distance effect, there were also clear Effects of Edge orientation on mycorrhizal diversity and community composition. While AMF OTU richness was higher at south- than at north-facing Edges, the opposite pattern was found for EcMF. Community composition of both mycorrhiza types also differed significantly between south- and north-facing Edges. We conclude that altered environmental conditions at forest Edges cause significant changes in mycorrhizal communities, which could subsequently affect ecosystem functioning.
Sabine Day - One of the best experts on this subject based on the ideXlab platform.
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Edge Effects on the Density of Cheirogaleus major
International Journal of Primatology, 2006Co-Authors: Andry Rajaonson, Sabine DayAbstract:We investigated how greater dwarf lemur (Cheirogaleus major) densities, ambient air temperature, and dendrometrics (tree height and diameter) varied along forest Edge-interior gradients in the Vohibola III Classified Forest in SE Madagascar. We also assessed if spatial variations in densities of Cheirogaleus major provide indirect evidence of increased predation pressure in the transition zone between Edge and interior forest habitats, i.e., an ecological trap. We conducted diurnal temperature surveys (N = 394) and nocturnal surveys of Cheirogaleus major (N = 182) over 2 yr along 4 1250-m transects that ran perpendicular to the forest Edge in Vohibola III. We did not see Cheirogaleus major from May to mid-September, and the highest sighting frequency occurred during October–November. Cheirogaleus major exhibited a negative Edge response because densities ranged from low levels in Edge habitats to higher levels in the forest interior. After we tested for spatial autocorrelation, Edge-related variations in densities of Cheirogaleus major covaried most strongly with tree diameter. Edge responses of Cheirogaleus major may reflect spatial variations in fruit and liana abundance, though data are needed on the precise relationship between tree diameter and food production to confirm the relationship. Edge-related variations in densities of Cheirogaleus major may also provide indirect evidence of an ecological trap. Testing and controlling for spatial autocorrelation should be important components of future studies of primate conservation biology and ecology.
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Edge Effects and their influence on lemur density and distribution in southeast madagascar
American Journal of Physical Anthropology, 2006Co-Authors: Andry Rajaonson, Sabine DayAbstract:Edge Effects are caused by the penetration of abiotic and biotic conditions from the matrix into forest interiors. Although Edge Effects influence the biogeography of many tropical organisms, they have not been studied directly in primates. Edge Effects are particularly relevant to lemurs due to the loss of 80-90% of forests in Madagascar. In this study, data are presented on how biotic Edge Effects influenced the distribution and density of lemurs in the Vohibola III Classified Forest in southeastern Madagascar. In total, 415 lemur surveys were conducted during June-October 2003 and May-September 2004 along six 1,250-m transects that ran perpendicular to the forest Edge. Data were also collected on lemur food trees along the six transects (density, height, diameter at breast height, area, volume, and distance to forest Edge). Four nocturnal species (Avahi laniger, Cheirogaleus major, Lepilemur microdon, and Microcebus rufus) and four diurnal species (Eulemur rubriventer, Eulemur fulvus rufus, Hapalemur grisesus griseus, and Propithecus diadema edwardsi) were sighted during surveys. Regression analyses of lemur densities as a function of distance to forest Edge provided Edge tolerances for A. laniger (Edge-tolerant), M. rufus (Edge-tolerant), E. rubriventer (Edge-tolerant or omnipresent), and H. g. griseus (omnipresent). The density and distribution of M. rufus and their foods trees were correlated. Edge-related variations in food quality and predation pressures may also be influencing lemurs in Vohibola III. Tolerance for Edge Effects may explain, in part, how lemurs have survived extreme habitat loss and forest fragmentation in southeastern Madagascar.
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Edge Effects on the Density of Cheirogaleus major
2005Co-Authors: Andry Rajaonson, Sabine DayAbstract:We investigated how greater dwarf lemur (Cheirogaleus major) densities, ambient air temperature, and dendrometrics (tree height and diameter) var-ied along forest Edge-interior gradients in the Vohibola III Classified For-est in SE Madagascar. We also assessed if spatial variations in densities of Cheirogaleus major provide indirect evidence of increased predation pres-sure in the transition zone between Edge and interior forest habitats, i.e., an ecological trap. We conducted diurnal temperature surveys (N = 394) and nocturnal surveys of Cheirogaleus major (N = 182) over 2 yr along 4 1250-m transects that ran perpendicular to the forest Edge in Vohibola III. We did not see Cheirogaleus major from May to mid-September, and the highest sighting frequency occurred during October–November. Cheirogaleus major exhibited a negative Edge response because densities ranged from low levels in Edge habitats to higher levels in the forest interior. After we tested for spatial autocorrelation, Edge-related variations in densities of Cheirogaleus major covaried most strongly with tree diameter. Edge responses of Cheirogaleus major may reflect spatial variations in fruit and liana abundance, though data are needed on the precise relationship between tree diameter and food pro-duction to confirm the relationship. Edge-related variations in densities of Cheirogaleus major may also provide indirect evidence of an ecological trap. Testing and controlling for spatial autocorrelation should be important com-ponents of future studies of primate conservation biology and ecology. KEY WORDS: Edge Effects; fruit abundance; lemurs; madagascar; predation; spatial autocor-relation
Margaux Boeraeve - One of the best experts on this subject based on the ideXlab platform.
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forest Edge Effects on the mycorrhizal communities of the dual mycorrhizal tree species alnus glutinosa l gaertn
Science of The Total Environment, 2019Co-Authors: Margaux Boeraeve, Olivier Honnay, Hans JacquemynAbstract:Abstract Forest conversion into agricultural land has resulted in a continuous decline in forest cover and in a reduced size and increased Edge-to-core ratio of the remaining fragments. Forest Edges are more directly exposed to sunlight, wind and pollutants and the resulting changes in habitat quality might have a large impact on plant and animal communities. Few studies, however, have focused on forest Edge Effects on mycorrhizal fungus communities. Here, we used high-throughput sequencing to study how communities of arbuscular mycorrhizal (AMF) and ectomycorrhizal fungi (EcMF), present in both the roots of the dual mycorrhizal tree Alnus glutinosa and in the soil, changed with increasing distance from the forest Edge within fragmented forests embedded in an intensively managed agricultural matrix. Overall, we found 158 AMF OTUs and 275 EcMF OTUs. Soil moisture content increased with increasing distance from the forest Edge, whereas soil nitrate concentration increased with increasing distance in south-facing and decreased in north-facing Edges. Distance to the forest Edge had a significant effect on EcMF community composition that largely overlapped with the observed changes in soil variables, especially soil moisture content. Apart from this distance effect, there were also clear Effects of Edge orientation on mycorrhizal diversity and community composition. While AMF OTU richness was higher at south- than at north-facing Edges, the opposite pattern was found for EcMF. Community composition of both mycorrhiza types also differed significantly between south- and north-facing Edges. We conclude that altered environmental conditions at forest Edges cause significant changes in mycorrhizal communities, which could subsequently affect ecosystem functioning.
Liza S Comita - One of the best experts on this subject based on the ideXlab platform.
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Edge Effects alter the role of fungi and insects in mediating functional composition and diversity of seedling recruits in a fragmented tropical forest
Annals of Botany, 2020Co-Authors: Meghna Krishnadas, Kavya Agarwal, Liza S ComitaAbstract:Background and aims In fragmented forests, proximity to forest Edges can favor the establishment of resource-acquisitive species over more resource-conservative species. During seedling recruitment, resource-acquisitive species may benefit from either higher light availability or weaker top-down Effects of natural enemies. The relative importance of light and enemies for recruitment has seldom been examined with respect to Edge Effects. Methods In a human-modified wet tropical forest in India, we first examined how functional traits indicative of resource-acquisitive vs. resource-conservative strategies-specific leaf area (SLA), leaf dry matter content (LDMC), wood density, and seed size-explained interspecific differences in densities of seedling recruits with distance to forest Edge. Then, we checked whether fungicide and insecticide treatments and canopy openness (proxy for light availability) explained Edge Effects on trait-mediated changes in seedling density. Finally, we examined whether light availability and natural enemy activity explained Edge Effects on functional diversity of seedling recruits. Key results Up to 60 m from Edges, recruit densities increased with decreasing seed size, but not at 90-100 m, where recruit densities increased with higher SLA. Trait-mediated variation in recruit densities changed with pesticides only at 90-100 m: compared to control plots, fungicide increased recruit densities for low SLA species and insecticide increased smaller-seeded species. For SLA, wood density, and seed size, functional diversity of recruits was higher at 90-100 m than at 0-5 m. At 90-100 m, fungicide decreased functional diversity for SLA and insecticide reduced seed size diversity compared to control plots. Canopy openness explained neither variation in recruit density in relation to traits nor functional diversity. Conclusions Altered biotic interactions can mediate local changes to trait composition and functional diversity during seedling recruitment in forest fragments, hinting at downstream Effects on the structure and function of human-modified forests.
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weaker plant enemy interactions decrease tree seedling diversity with Edge Effects in a fragmented tropical forest
Nature Communications, 2018Co-Authors: Meghna Krishnadas, Liza S Comita, Robert Bagchi, Sachin SridharaAbstract:In fragmented forests, tree diversity declines near Edges but the ecological processes underlying this loss of diversity remain poorly understood. Theory predicts that top-down regulation of seedling recruitment by insect herbivores and fungal pathogens contributes to maintaining tree diversity in forests, but it is unknown whether proximity to forest Edges compromises these diversity-enhancing biotic interactions. Here we experimentally demonstrate that weakened activity of fungal pathogens and insect herbivores reduced seedling diversity, despite similar diversity of seed rain, during recruitment near forest Edges in a human-modified tropical landscape. Only at sites farthest from forest Edges (90–100 m) did the application of pesticides lower seedling diversity relative to control plots. Notably, lower seedling diversity corresponded with weaker density-dependent mortality attributable to insects and fungi during the seed-to-seedling transition. We provide mechanistic evidence that Edge-Effects can manifest as cryptic losses of crucial biotic interactions that maintain diversity. Tree diversity decreases at the Edges of fragmented forests. Here, Krishnadas et al. find that weaker top-down regulation by insects and fungal pathogens during seedling recruitment contributes to reduced tree seedling diversity near forest Edges in a human-modified landscape.
Olivier Honnay - One of the best experts on this subject based on the ideXlab platform.
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forest Edge Effects on the mycorrhizal communities of the dual mycorrhizal tree species alnus glutinosa l gaertn
Science of The Total Environment, 2019Co-Authors: Margaux Boeraeve, Olivier Honnay, Hans JacquemynAbstract:Abstract Forest conversion into agricultural land has resulted in a continuous decline in forest cover and in a reduced size and increased Edge-to-core ratio of the remaining fragments. Forest Edges are more directly exposed to sunlight, wind and pollutants and the resulting changes in habitat quality might have a large impact on plant and animal communities. Few studies, however, have focused on forest Edge Effects on mycorrhizal fungus communities. Here, we used high-throughput sequencing to study how communities of arbuscular mycorrhizal (AMF) and ectomycorrhizal fungi (EcMF), present in both the roots of the dual mycorrhizal tree Alnus glutinosa and in the soil, changed with increasing distance from the forest Edge within fragmented forests embedded in an intensively managed agricultural matrix. Overall, we found 158 AMF OTUs and 275 EcMF OTUs. Soil moisture content increased with increasing distance from the forest Edge, whereas soil nitrate concentration increased with increasing distance in south-facing and decreased in north-facing Edges. Distance to the forest Edge had a significant effect on EcMF community composition that largely overlapped with the observed changes in soil variables, especially soil moisture content. Apart from this distance effect, there were also clear Effects of Edge orientation on mycorrhizal diversity and community composition. While AMF OTU richness was higher at south- than at north-facing Edges, the opposite pattern was found for EcMF. Community composition of both mycorrhiza types also differed significantly between south- and north-facing Edges. We conclude that altered environmental conditions at forest Edges cause significant changes in mycorrhizal communities, which could subsequently affect ecosystem functioning.
