Camelid herding may homogenize Andean grassland plant communities

Abstract

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