Managing ecosystems effectively for the maintenance of biodiversity and ecosystem functions and s... more Managing ecosystems effectively for the maintenance of biodiversity and ecosystem functions and services requires to understand how these ecosystems are changing and what are the drivers behind these changes. The resurvey of plant communities sampled some decades ago is increasingly used for this purpose. We used a life‐history trait‐based approach to test a number of hypothesized drivers behind decadal changes (1970–2015) in the herb layer of an ancient broadleaved lowland forest exhibiting contrasted soil and management types, while minimizing potential relocation and observer errors. Process‐based hypotheses were tested using paired comparisons (old vs. new records) of community‐weighted means and conditional inference classification trees for a number of traits across soil and management types. We then investigated how these processes impacted species composition and diversity within stands, among stands and at the entire forest scale, using metrics of taxonomic, functional and ...
Abstract Increasing connectivity among habitat patches is assumed to mitigate the effects of frag... more Abstract Increasing connectivity among habitat patches is assumed to mitigate the effects of fragmentation on biodiversity, leading to the emergence of green and blue infrastructures in public policies as corridors facilitating movements of species within fragmented landscapes. But still, the scientific knowledge and tools for identifying critical features that make a corridor efficient for biodiversity conservation, and for guiding their establishment and management are still scarce. Here, we define three types of indicator species based on their ecological requirements and dispersal traits in the context of forest metacommunities embedded into agricultural landscapes in N France. We then evaluate whether hedgerows can act as corridors for forest herb species and if this can be predicted from the occurrence of the selected indicator species. We show that among each socio-ecological group of forest herb species, (i) the best disperser (“scout” species) indicates habitat suitability for the other species of the group, hence predicts a colonization credit; (ii) the species with intermediate dispersal traits (“median” species) indicates forest species richness and composition of a given hedgerow. In contrast, the worst dispersers (“focal” species) have a low indicator power, as a probable consequence of extinction events occurring in hedgerows, where ecological conditions are suboptimal with respect of forest species. The quality of the corridor increases with the width, height and age of hedgerows, but decreases with increasing land use intensity in adjacent lands. We conclude that process-based indicator species can be valuable tools to assess the efficiency of ecological corridors in fragmented landscapes.
ABSTRACT The relative importance of local, regional and historical factors in controlling the spa... more ABSTRACT The relative importance of local, regional and historical factors in controlling the spatial patterns of plant species distribution is still poorly known and challenging for conservation ecology. We conducted an empirical study to link the spatial variation of species and environments among forest patches embedded in contrasted agricultural matrices. We compared how forest herb communities responded to spatial environmental gradients and past forest cover. We found low values of β-diversity in both unfragmented and highly fragmented systems, independently from local and regional diversities. As fragmentation increased, the spatial structure of local plant communities was more complex and spatial effects explained an increasing proportion of β-diversity, suggesting that the importance of dispersal limitations increased and played out at broad spatial scales. However, where spatio-temporal isolation of forest patches was the highest, local species assemblages could not be explained, suggesting that the metacommunity functioning was disrupted. Where the historical continuity was high, local environmental characteristics explained a significant amount of species assemblages within metacommunities, suggesting habitat-selection processes. Beta-diversity and variations in presence–absence of species were also influenced by the intensity of landscape management, via the permeability of both forest edges and the matrix. This spatially-explicit analysis of metacommunities revealed that forest fragmentation impacts beta-diversity by altering not only the relative importance of deterministic and stochastic processes, but also the spatial scales at which they act. These results provide empirical support for the conservation of ancient forests and the maintenance of a high connectedness between fragments within agricultural landscapes.
Aim Macroclimate is a major determinant of large-scale diversity patterns.
However, the influence... more Aim Macroclimate is a major determinant of large-scale diversity patterns. However, the influence of smaller-scale factors on local diversity across large spatial extents is not well documented. Here, we quantify the relative importance of local (patch-scale), landscape-scale and macroclimatic drivers of herbaceous species diversity in small forest patches in agricultural landscapes across Europe. Location Deciduous forest patches in eight regions along a macroclimatic gradient from southern France to central Sweden and Estonia. Methods The diversity of forest specialists and generalists at three levels (whole forest patch, sampling plots within patches and between scales) was related to patch-scale (forest area, age, abiotic and biotic heterogeneity), landscape-scale (amount of forest, grasslands and hedgerows around the patch, patch isolation) and macroclimatic variables (temperature and precipitation) using generalized linear mixed models and variation partitioning for each group of variables. Results The total amount of explained variation in diversity ranged from 8% for plot-scale diversity of generalists to 54% for patch-scale diversity of forest specialists. Patch-scale variables always explained more than 60% of the explained variation in diversity, mainly due to the positive effect of within-patch heterogeneity on patch-scale and between-scale diversities and to the positive effect of patch age on plot-scale diversity of forest specialists. Landscape-scale variables mainly contributed to the amount of explained variation in plot-scale diversity, being more important for forest specialists (21%) than for generalists (18%). Macroclimatic variables contributed a maximum of 11% to the plot-scale diversity of generalists. Main conclusions Macroclimate poorly predicts local diversity across Europe, and herbaceous diversity is mainly explained by habitat features, less so by landscape structure.We show the importance of conserving old forest patches as refugia for typical forest species, and of enhancing the landscape context around the patches by reducing the degree of disturbance caused by agriculture.
ABSTRACT Context Determining regional and local processes that govern the maintenance of biodiver... more ABSTRACT Context Determining regional and local processes that govern the maintenance of biodiversity and assessing their relative importance remain major research challenges in landscape ecology. In riparian systems, propagule dispersal and disturbance are constrained by longitudinal and lateral water flows, but riparian forests in temperate human-dominated landscapes have received little attention so far. Objectives We investigated how the longitudinal position along the river course and the lateral position to the riverbed structure forest plant communities subjected to flooding. Methods We studied vegetation, soil seed bank, hydrochorous seed rain and environmental conditions along 23 transects perpendicular to the river in two forest floodplains in the North of France. We used generalized linear mixed models to assess the relative importance of longitudinal distance, relative elevation, and their interaction on both species richness in a given compartment and species turnover between compartments. Results Relative elevation to the riverbed was the main factor explaining species richness of vegetation and water seed deposit, but not of the seed bank. Vegetation was the most species-rich at low elevations, where the number of water-dispersed seeds and related species richness were maximal. The longitudinal position within the riparian forest had no effect on vegetation and seed bank richness. Dissimilarity between the seed bank and the seed rain increased with relative elevation. Conclusion Lateral much more than longitudinal movements of water create a strong gradient in seed rain intensity that structures plant communities. Flooding is important to species dispersal, hence to the conservation of species-rich plant communities within human-pressured landscapes.
In forest ecosystems, trees interact with understorey species through negative (e.g. soil water a... more In forest ecosystems, trees interact with understorey species through negative (e.g. soil water and nutrient depletion, shading) or positive (e.g. nitrogen fixation) effects on these species' environmental conditions. Interference between neighboring plants through the release of allelochemicals into the environment has been widely reported. Hornbeam (Carpinus betulus L.,Betulaceae) is a shade tolerant tree species, which is widely distributed on deep fertile soils with wide adaptability to varied environmental conditions. It is widely distributed in north - west and central Europe where it has long been promoted as coppice wood. As a result, many deciduous forests of the temperate area now consist of oak-hornbeam forests, inherited from the coppice-with-standards silviculture. Many field observations have emphasized the fact that very poor vegetation is seen under the canopy of Carpinus betulus as compared to adjoining forest areas. Among potential causes for this, competitive ...
Managing ecosystems effectively for the maintenance of biodiversity and ecosystem functions and s... more Managing ecosystems effectively for the maintenance of biodiversity and ecosystem functions and services requires to understand how these ecosystems are changing and what are the drivers behind these changes. The resurvey of plant communities sampled some decades ago is increasingly used for this purpose. We used a life‐history trait‐based approach to test a number of hypothesized drivers behind decadal changes (1970–2015) in the herb layer of an ancient broadleaved lowland forest exhibiting contrasted soil and management types, while minimizing potential relocation and observer errors. Process‐based hypotheses were tested using paired comparisons (old vs. new records) of community‐weighted means and conditional inference classification trees for a number of traits across soil and management types. We then investigated how these processes impacted species composition and diversity within stands, among stands and at the entire forest scale, using metrics of taxonomic, functional and ...
Abstract Increasing connectivity among habitat patches is assumed to mitigate the effects of frag... more Abstract Increasing connectivity among habitat patches is assumed to mitigate the effects of fragmentation on biodiversity, leading to the emergence of green and blue infrastructures in public policies as corridors facilitating movements of species within fragmented landscapes. But still, the scientific knowledge and tools for identifying critical features that make a corridor efficient for biodiversity conservation, and for guiding their establishment and management are still scarce. Here, we define three types of indicator species based on their ecological requirements and dispersal traits in the context of forest metacommunities embedded into agricultural landscapes in N France. We then evaluate whether hedgerows can act as corridors for forest herb species and if this can be predicted from the occurrence of the selected indicator species. We show that among each socio-ecological group of forest herb species, (i) the best disperser (“scout” species) indicates habitat suitability for the other species of the group, hence predicts a colonization credit; (ii) the species with intermediate dispersal traits (“median” species) indicates forest species richness and composition of a given hedgerow. In contrast, the worst dispersers (“focal” species) have a low indicator power, as a probable consequence of extinction events occurring in hedgerows, where ecological conditions are suboptimal with respect of forest species. The quality of the corridor increases with the width, height and age of hedgerows, but decreases with increasing land use intensity in adjacent lands. We conclude that process-based indicator species can be valuable tools to assess the efficiency of ecological corridors in fragmented landscapes.
ABSTRACT The relative importance of local, regional and historical factors in controlling the spa... more ABSTRACT The relative importance of local, regional and historical factors in controlling the spatial patterns of plant species distribution is still poorly known and challenging for conservation ecology. We conducted an empirical study to link the spatial variation of species and environments among forest patches embedded in contrasted agricultural matrices. We compared how forest herb communities responded to spatial environmental gradients and past forest cover. We found low values of β-diversity in both unfragmented and highly fragmented systems, independently from local and regional diversities. As fragmentation increased, the spatial structure of local plant communities was more complex and spatial effects explained an increasing proportion of β-diversity, suggesting that the importance of dispersal limitations increased and played out at broad spatial scales. However, where spatio-temporal isolation of forest patches was the highest, local species assemblages could not be explained, suggesting that the metacommunity functioning was disrupted. Where the historical continuity was high, local environmental characteristics explained a significant amount of species assemblages within metacommunities, suggesting habitat-selection processes. Beta-diversity and variations in presence–absence of species were also influenced by the intensity of landscape management, via the permeability of both forest edges and the matrix. This spatially-explicit analysis of metacommunities revealed that forest fragmentation impacts beta-diversity by altering not only the relative importance of deterministic and stochastic processes, but also the spatial scales at which they act. These results provide empirical support for the conservation of ancient forests and the maintenance of a high connectedness between fragments within agricultural landscapes.
Aim Macroclimate is a major determinant of large-scale diversity patterns.
However, the influence... more Aim Macroclimate is a major determinant of large-scale diversity patterns. However, the influence of smaller-scale factors on local diversity across large spatial extents is not well documented. Here, we quantify the relative importance of local (patch-scale), landscape-scale and macroclimatic drivers of herbaceous species diversity in small forest patches in agricultural landscapes across Europe. Location Deciduous forest patches in eight regions along a macroclimatic gradient from southern France to central Sweden and Estonia. Methods The diversity of forest specialists and generalists at three levels (whole forest patch, sampling plots within patches and between scales) was related to patch-scale (forest area, age, abiotic and biotic heterogeneity), landscape-scale (amount of forest, grasslands and hedgerows around the patch, patch isolation) and macroclimatic variables (temperature and precipitation) using generalized linear mixed models and variation partitioning for each group of variables. Results The total amount of explained variation in diversity ranged from 8% for plot-scale diversity of generalists to 54% for patch-scale diversity of forest specialists. Patch-scale variables always explained more than 60% of the explained variation in diversity, mainly due to the positive effect of within-patch heterogeneity on patch-scale and between-scale diversities and to the positive effect of patch age on plot-scale diversity of forest specialists. Landscape-scale variables mainly contributed to the amount of explained variation in plot-scale diversity, being more important for forest specialists (21%) than for generalists (18%). Macroclimatic variables contributed a maximum of 11% to the plot-scale diversity of generalists. Main conclusions Macroclimate poorly predicts local diversity across Europe, and herbaceous diversity is mainly explained by habitat features, less so by landscape structure.We show the importance of conserving old forest patches as refugia for typical forest species, and of enhancing the landscape context around the patches by reducing the degree of disturbance caused by agriculture.
ABSTRACT Context Determining regional and local processes that govern the maintenance of biodiver... more ABSTRACT Context Determining regional and local processes that govern the maintenance of biodiversity and assessing their relative importance remain major research challenges in landscape ecology. In riparian systems, propagule dispersal and disturbance are constrained by longitudinal and lateral water flows, but riparian forests in temperate human-dominated landscapes have received little attention so far. Objectives We investigated how the longitudinal position along the river course and the lateral position to the riverbed structure forest plant communities subjected to flooding. Methods We studied vegetation, soil seed bank, hydrochorous seed rain and environmental conditions along 23 transects perpendicular to the river in two forest floodplains in the North of France. We used generalized linear mixed models to assess the relative importance of longitudinal distance, relative elevation, and their interaction on both species richness in a given compartment and species turnover between compartments. Results Relative elevation to the riverbed was the main factor explaining species richness of vegetation and water seed deposit, but not of the seed bank. Vegetation was the most species-rich at low elevations, where the number of water-dispersed seeds and related species richness were maximal. The longitudinal position within the riparian forest had no effect on vegetation and seed bank richness. Dissimilarity between the seed bank and the seed rain increased with relative elevation. Conclusion Lateral much more than longitudinal movements of water create a strong gradient in seed rain intensity that structures plant communities. Flooding is important to species dispersal, hence to the conservation of species-rich plant communities within human-pressured landscapes.
In forest ecosystems, trees interact with understorey species through negative (e.g. soil water a... more In forest ecosystems, trees interact with understorey species through negative (e.g. soil water and nutrient depletion, shading) or positive (e.g. nitrogen fixation) effects on these species' environmental conditions. Interference between neighboring plants through the release of allelochemicals into the environment has been widely reported. Hornbeam (Carpinus betulus L.,Betulaceae) is a shade tolerant tree species, which is widely distributed on deep fertile soils with wide adaptability to varied environmental conditions. It is widely distributed in north - west and central Europe where it has long been promoted as coppice wood. As a result, many deciduous forests of the temperate area now consist of oak-hornbeam forests, inherited from the coppice-with-standards silviculture. Many field observations have emphasized the fact that very poor vegetation is seen under the canopy of Carpinus betulus as compared to adjoining forest areas. Among potential causes for this, competitive ...
Uploads
Papers by Deborah Closset-Kopp
However, the influence of smaller-scale factors on local diversity across large spatial
extents is not well documented. Here, we quantify the relative importance of local
(patch-scale), landscape-scale and macroclimatic drivers of herbaceous species
diversity in small forest patches in agricultural landscapes across Europe.
Location Deciduous forest patches in eight regions along a macroclimatic gradient
from southern France to central Sweden and Estonia.
Methods The diversity of forest specialists and generalists at three levels (whole
forest patch, sampling plots within patches and between scales) was related to
patch-scale (forest area, age, abiotic and biotic heterogeneity), landscape-scale
(amount of forest, grasslands and hedgerows around the patch, patch isolation) and
macroclimatic variables (temperature and precipitation) using generalized linear
mixed models and variation partitioning for each group of variables.
Results The total amount of explained variation in diversity ranged from 8% for
plot-scale diversity of generalists to 54% for patch-scale diversity of forest specialists.
Patch-scale variables always explained more than 60% of the explained variation
in diversity, mainly due to the positive effect of within-patch heterogeneity on
patch-scale and between-scale diversities and to the positive effect of patch age on
plot-scale diversity of forest specialists. Landscape-scale variables mainly contributed
to the amount of explained variation in plot-scale diversity, being more
important for forest specialists (21%) than for generalists (18%). Macroclimatic
variables contributed a maximum of 11% to the plot-scale diversity of generalists.
Main conclusions Macroclimate poorly predicts local diversity across Europe,
and herbaceous diversity is mainly explained by habitat features, less so by landscape
structure.We show the importance of conserving old forest patches as refugia
for typical forest species, and of enhancing the landscape context around the
patches by reducing the degree of disturbance caused by agriculture.
However, the influence of smaller-scale factors on local diversity across large spatial
extents is not well documented. Here, we quantify the relative importance of local
(patch-scale), landscape-scale and macroclimatic drivers of herbaceous species
diversity in small forest patches in agricultural landscapes across Europe.
Location Deciduous forest patches in eight regions along a macroclimatic gradient
from southern France to central Sweden and Estonia.
Methods The diversity of forest specialists and generalists at three levels (whole
forest patch, sampling plots within patches and between scales) was related to
patch-scale (forest area, age, abiotic and biotic heterogeneity), landscape-scale
(amount of forest, grasslands and hedgerows around the patch, patch isolation) and
macroclimatic variables (temperature and precipitation) using generalized linear
mixed models and variation partitioning for each group of variables.
Results The total amount of explained variation in diversity ranged from 8% for
plot-scale diversity of generalists to 54% for patch-scale diversity of forest specialists.
Patch-scale variables always explained more than 60% of the explained variation
in diversity, mainly due to the positive effect of within-patch heterogeneity on
patch-scale and between-scale diversities and to the positive effect of patch age on
plot-scale diversity of forest specialists. Landscape-scale variables mainly contributed
to the amount of explained variation in plot-scale diversity, being more
important for forest specialists (21%) than for generalists (18%). Macroclimatic
variables contributed a maximum of 11% to the plot-scale diversity of generalists.
Main conclusions Macroclimate poorly predicts local diversity across Europe,
and herbaceous diversity is mainly explained by habitat features, less so by landscape
structure.We show the importance of conserving old forest patches as refugia
for typical forest species, and of enhancing the landscape context around the
patches by reducing the degree of disturbance caused by agriculture.