Browsing by Author "Bertin Angeline"
Ecological uniqueness across multiple levels of biodiversity in a Chilean watershed
(2024/06/01) Borquez Jessica; Sampertegui Sandra; Wallberg Britt N.; Coral-Santacruz Diana; Ruiz Victor H.; Samollow Paul B.; Gouin Nicolas; Bertin Angeline
To effectively address biodiversity loss, it is essential to prioritize conservation efforts by identifying areas of high conservation value. Ecological uniqueness is a valuable metric for this purpose that decomposes beta diversity into local contributions to beta diversity (LCBD), thereby measuring the contribution of each site within a region to overall biodiversity variation. LCBD has been used extensively to evaluate ecological uniqueness from community composition data, but biodiversity is a multifaceted concept, and community-based ecological uniqueness may not capture the full range of ecological uniqueness occurring at other levels of biological organization. We investigated ecological uniqueness estimates derived from community and species population levels in a watershed of south-central Chile and analyzed their responses to water and habitat quality variables. Ecological uniqueness was estimated at the community level from fish and macroinvertebrate assemblages and at the population level using genetic and morphological data gathered for two invertebrates, the gastropod Chilina dombeiana and the water bug Aquarius chilensis. Our results revealed low spatial congruence between the levels of ecological uniqueness calculated for these different biodiversity components, with mismatches occurring among sites with high LCBD values. Water and habitat quality were major drivers of beta diversity in this watershed, accounting for 43.8% to 74.3% of the spatial variation in LCBDs, and their effects differed among the ecological uniqueness estimates. Overall, our results underscore the idiosyncratic nature of ecological uniqueness metrics, emphasizing the importance of using multiple components of biodiversity to guide conservation actions.
Effects of land cover and habitat condition on the bird community along a gradient of agricultural development within an arid watershed of Chile
(2023/10/15) Petit Mariangeles; Celis Cristian; Weideman Craig; Gouin Nicolas; Bertin Angeline
Agricultural activities are a major cause of change in avifauna, frequently resulting in diminished diversity and biotic homogenization, and ultimately compromising ecosystem functioning and resilience. Arid ecosystems, which provide habitat for numerous native and endemic bird species, are vulnerable to global change and valuable in predicting future ecosystem shifts in regions undergoing aridification as a result of climate change. However, the impacts of agriculture on bird communities in arid ecosystems are understudied. Here, we evaluate these impacts in the arid Limari watershed in north-central Chile, a region that has experienced extensive land use conversion to agriculture over the past 50 years. Specifically, we investigated current spatial patterns of avian beta diversity and the impact of landscape context on this diversity facet. Moreover, we evaluated how bird species respond to land cover and habitat conditions and the role of specific bird traits in this regard. To achieve this, we evaluated taxonomic and functional beta diversity across 26 sites distributed along a gradient of agricultural development, applied a beta diversity decomposition procedure, and carried out hierarchical joint species distribution modeling. Our study revealed high taxonomic but low functional beta diversity of the avifauna in the Limari watershed, potentially indicative of past functional homogenization. Contrary to our initial expectations, present agricultural practices did not decrease beta diversity. While human-related landscape elements and agricultural features mostly had neutral or positive effects on bird occurrence, they negatively affected endemic species and certain bird traits related to diet and habitat. Riparian vegetation cover and quality, unrelated to agricultural and urban development, emerged as key factors structuring the regional bird community, and influenced beta diversity. Our results underscore the profound influence of land use change on the avian community in this arid region and the vital role of riparian ecosystems in this regard. Balancing conservation objectives with agricultural development is key to ensuring both the persistence of several functional groups in the region as well as the ecosystem services they provide.
Effects of land cover and habitat condition on the bird community along a gradient of agricultural development within an arid watershed of Chile
(2023/10/15) Petit Mariangeles; Celis Cristian; Weideman Craig; Gouin Nicolas; Bertin Angeline
Agricultural activities are a major cause of change in avifauna, frequently resulting in diminished diversity and biotic homogenization, and ultimately compromising ecosystem functioning and resilience. Arid ecosystems, which provide habitat for numerous native and endemic bird species, are vulnerable to global change and valuable in predicting future ecosystem shifts in regions undergoing aridification as a result of climate change. However, the impacts of agriculture on bird communities in arid ecosystems are understudied. Here, we evaluate these impacts in the arid Limari watershed in north-central Chile, a region that has experienced extensive land use conversion to agriculture over the past 50 years. Specifically, we investigated current spatial patterns of avian beta diversity and the impact of landscape context on this diversity facet. Moreover, we evaluated how bird species respond to land cover and habitat conditions and the role of specific bird traits in this regard. To achieve this, we evaluated taxonomic and functional beta diversity across 26 sites distributed along a gradient of agricultural development, applied a beta diversity decomposition procedure, and carried out hierarchical joint species distribution modeling. Our study revealed high taxonomic but low functional beta diversity of the avifauna in the Limari watershed, potentially indicative of past functional homogenization. Contrary to our initial expectations, present agricultural practices did not decrease beta diversity. While human-related landscape elements and agricultural features mostly had neutral or positive effects on bird occurrence, they negatively affected endemic species and certain bird traits related to diet and habitat. Riparian vegetation cover and quality, unrelated to agricultural and urban development, emerged as key factors structuring the regional bird community, and influenced beta diversity. Our results underscore the profound influence of land use change on the avian community in this arid region and the vital role of riparian ecosystems in this regard. Balancing conservation objectives with agricultural development is key to ensuring both the persistence of several functional groups in the region as well as the ecosystem services they provide.
Simulation-based insights into community uniqueness within fragmented landscapes
(2023/10/01) Lozada Adriana; Day Casey C.; Landguth Erin L.; Bertin Angeline
ContextLocal contribution to beta-diversity (LCBD) assesses community composition uniqueness of sites within a region. While it is useful to identify sites with exceptional species composition and, thus, prioritize conservation actions, it is unclear what determines community uniqueness in patchy habitats.ObjectivesThe goal of this study was to clarify the processes underlying community uniqueness in fragmented landscapes and understand how habitat characteristics and community characteristics affect this beta-based diversity indicator.MethodsWe simulated neutral metacommunities and used a variance-based method to assess the contribution of each habitat patch to total beta-diversity, both in terms of replacement and abundance difference. Then, we analyzed the effects of patch and metacommunity characteristics on LCBD.ResultsCommunity uniqueness in species replacement and richness/abundance differences responded differently to community and patch features. Patch quality was the habitat attribute with the strongest effects on all community uniqueness aspects, leading to singular assemblages with high species richness and abundance of rare species. While patch connectivity promoted singular assemblages with high richness, patch size increased community uniqueness in species replacement over time, favoring assemblages with high abundances of rare species.ConclusionsCommunity uniqueness in species replacement and richness/abundance differences convey different information and should be considered separately to propose adequate conservation strategies. Habitat quality emerged as a critical factor in shaping beta-diversity, suggesting that it should be a primary focus of conservation efforts. Future studies are needed to evaluate the generality of our results in different spatial and ecological contexts.