Browsing by Autor "P.A. Verweij"

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Camelid herding may homogenize Andean grassland plant communities
(2023) Ana Patricia Sandoval‐Calderon; Ana P Sandoval-Calderon; Merel B. Soons; Marijke van Kuijk; P.A. Verweij; Kathryn E. Barry; Yann Hautier
10 The current global decline in biodiversity is a matter of pressing concern, necessitating the 11 conservation of diverse ecosystems across various spatial scales. Regions such as the 12 tropical Andes face the imminent threat of biotic homogenization due to intensive 13 livestock grazing, posing a significant risk to biodiversity. This study is focused on the 14 sub-humid grasslands of northwestern Bolivia, within the the National Park Apolobamba. 15 We investigate the influence of environmental factors on plant diversity within and among 16 communities across seven distinct sites. Our research reveals that local plant diversity, 17 quantified by species richness and the inverse Simpson index, is predominantly shaped by 18 soil pH. Notably, more acidic soil is associated with diminished diversity. Furthermore, 19 our findings highlight that the dissimilarity in species composition among local 20 communities may be linked to grazing intensity. This suggests that intensified grazing may 21 have the potential to homogenize plant communities across the landscape. A concerning 22 implication is the likelihood of communities becoming dominated by acquisitive species, 23 leaving them more susceptible to the impacts of climate variability. The study underlines 24 the necessity to analyze multiple facets of diversity for a comprehensive understanding of 25 the environmental factors regulating and therefore to address potential drivers of diversity 26 loss. To mitigate these threats, managers may consider adjusting livestock quantities and 27 the spatial range used by grazers, aiming to sustain multiple aspects of plant diversity and 28 prevent homogenization and degradation of grasslands in a changing world. 29
Camelid herding may homogenize Andean grassland plant communities
(Elsevier BV, 2024) Ana Patricia Sandoval‐Calderon; Merel B. Soons; Marijke van Kuijk; P.A. Verweij; Kathryn E. Barry; Yann Hautier
• The variance in alpha plant diversity is primarily influenced by soil pH. Higher acidity in the topsoil is linked with decreased species richness and lower Inverse Simpson index. • Beta diversity, quantified by the Bary-Curtis dissimilarity index, is predominantly shaped by grazing intensity, suggesting that camelid herding may homogenize plant communities across the landscape. • Elevated grazing intensities are associated with shifts in plant community composition towards dominance by acquisitive species. This trend may render ecosystems more susceptible to the impacts of climate variability. The current global decline in biodiversity is a matter of pressing concern, necessitating the conservation of diverse ecosystems across various spatial scales. Regions such as the tropical Andes face the imminent threat of biotic homogenization due to intensive livestock grazing, posing a significant risk to biodiversity. This study is focused on the sub-humid grasslands of northwestern Bolivia, within the the National Park Apolobamba. We surveyed a total of 105 plots distributed across seven sites, representing a natural gradient of grazing intensity. Within each site, the plots were organized into five clusters to explore the impact of environmental factors on plant diversity within and among communities. Our research reveals that local plant diversity, quantified by species richness and the inverse Simpson index, is predominantly shaped by soil pH. Notably, more acidic soil is associated with diminished diversity. Furthermore, our findings highlight that the dissimilarity in species composition among local communities may be linked to grazing intensity. This suggests that intensified grazing may have the potential to homogenize plant communities across the landscape. A concerning implication is the likelihood of communities becoming dominated by acquisitive species, leaving them more susceptible to the impacts of climate variability. The study underlines the necessity to analyze multiple facets of diversity for a comprehensive understanding of the environmental factors regulating and therefore to address potential drivers of diversity loss. To mitigate these threats, managers may consider adjusting livestock quantities and the spatial range used by grazers, aiming to sustain multiple aspects of plant diversity and prevent homogenization and degradation of grasslands in a changing world.
Mining expansion may reduce livestock but facilitate vicuñas recovery in tropical Puna of South America
(Frontiers Media, 2024) Ana Patricia Sandoval‐Calderon; Marijke van Kuijk; Yann Hautier; Humber Alberto; P.A. Verweij
High-elevation tropical grasslands in South America are vital for sustaining the livelihoods of indigenous communities, particularly in the Central Andes where herding of both wild and domesticated camelids has been a primary socio-economic activity for centuries. However, these grasslands are facing challenges due to changes in land use, economic activities, and climate, posing threats to the sustainability of camelid herding. Here, we determine the intricate relationship between land use management and camelid populations of the highlands of Apolobamba National Park in Bolivia. We identified two critical milestones in land use management across the indigenous communities: the creation of the Tierra Comunitaria de Origen (TCO) in 1999 and the expansion of the National Park in 2000. These initiatives collectively resulted in the diversification of livelihood sources by increasing the number of mining concessions and facilitating the management of wild camelids for their wool and fibers, catering to international markets. We found that this diversification of livelihood sources was negatively related to the densities of domesticated camelids across the studied communities. In contrast, the densities of wild camelids populations increased with an increasing number of mining concessions, likely due to local conservation efforts and reduced competition with livestock. Our results indicate a potential shift in land use management strategies and suggest that mining activities encroach upon pastoralism practices within indigenous communities. Understanding the long-term effects of land use changes is essential for providing comprehensive and sustainable land use strategies that will support both grasslands and animal conservation while providing livelihood security in this ecologically sensitive region.
The effect of livestock grazing on plant diversity and productivity of mountainous grasslands in South America – <i>A meta‐analysis</i>
(Wiley, 2024) Ana Patricia Sandoval‐Calderon; Nerea Rubio Echazarra; Marijke van Kuijk; P.A. Verweij; Merel B. Soons; Yann Hautier
Mountainous grasslands in South America, characterized by their high diversity, provide a wide range of contributions to people, including water regulation, soil erosion prevention, livestock feed provision, and preservation of cultural heritage. Prior research has highlighted the significant role of grazing in shaping the diversity and productivity of grassland ecosystems, especially in highly productive, eutrophic systems. In such environments, grazing has been demonstrated to restore grassland plant diversity by reducing primary productivity. However, it remains unclear whether these findings are applicable to South American mountainous grasslands, where plants are adapted to different environmental conditions. To address this uncertainty, we conducted a meta-analysis of experiments excluding livestock grazing to assess its impact on plant diversity and productivity across mountainous grasslands in South America. In alignment with studies in temperate grasslands, our findings indicated that herbivore exclusion resulted in increased aboveground biomass but reduced species richness and Shannon diversity. The effects of grazing exclusion became more pronounced with longer durations of exclusion; nevertheless, they remained resilient to various climatic conditions, including mean annual precipitation and mean annual temperature, as well as the evolutionary history of grazing. In contrast to results observed in temperate grasslands, the reduction in species richness due to herbivore exclusion was not associated with increased aboveground biomass. This suggests that the processes governing (sub)tropical grassland plant diversity may differ from those in temperate grasslands. Consequently, further research is necessary to better understand the specific factors influencing plant diversity and productivity in South American montane grasslands and to elucidate the ecological implications of herbivore exclusion in these unique ecosystems.