Past and Recent Effects of Livestock Activity on the Genetic Diversity and Population Structure of Native Guanaco Populations of Arid Patagonia

Abstract

Extensive livestock production and urbanization entail modifications of natural landscapes, including installation of fences, development of agriculture, urbanization of natural areas, and construction of roads and infrastructure that, together, impact native fauna. Here, we evaluate the diversity and genetic structure of endemic guanacos (Lama guanicoe) of the Monte and Patagonian Steppe of central Argentina, which have been reduced and displaced by sheep ranching and other impacts of human activities. Analyses of genetic variation of microsatellite loci and d-loop revealed high levels of genetic variation and latitudinal segregation of mitochondrial haplotypes. There were indications of at least two historical populations in the Monte and the Patagonian Steppe based on shared haplotypes and shared demographic history among localities. Currently, guanacos are structured into three groups that were probably reconnected relatively recently, possibly facilitated by a reduction of sheep and livestock in recent decades and a recovery of the guanaco populations. These results provide evidence of the genetic effects of livestock activity and urbanization on wild herbivore populations, which were possibly exacerbated by an arid environment with limited productive areas. The results highlight the importance of enacting conservation management plans to ensure the persistence of ancestral and ecologically functional populations of guanacos.

Lessons of 15,000 Years of Human–Wildlife Interaction for Conservation in Patagonia in the 21st Century

“…The guanaco recovery has been most dramatic in southern Patagonia, where a large proportion of ranches have been abandoned for two decades or more [50]. The guanaco population range today is continuous in southern Patagonia and still highly fragmented in northern Patagonia, though some high-density populations occur in both areas (Figure 1, Baldi et al's unpublished manuscript, [51]). Similarly, pumas have recovered most of their early 20th century distribution in the steppe [52].…”

“…The recolonization of southern Patagonia by guanacos from northern Patagonia 12,000 years ago, as evidenced by genetic data [19], indicates a high capacity for longdistance movements and the importance of maintaining connectivity to prevent extinction of small, isolated guanaco populations. Even in recent times, with barriers that include high livestock densities, fences, and persecution by ranchers, according to genetic evidence, guanacos appear to have maintained dispersal over long distances [51].…”

History of Diversification and Adaptation from North to South Revealed by Genomic Data: Guanacos from the Desert to Sub-Antarctica

“…Despite this evolutionary perspective, the current status of the guanaco presents a contrasting scenario. The impact of human activities on genetic diversity and the recent demographic history of the species have not been explored at the local level for a few populations ( González et al 2014 ; Mesas, Baldi, et al 2021 ; Mesas, Cuéllar-Soto, et al 2021 ).…”

Microsatellite-Based Genetic Diversity and Population Structure of Huacaya Alpacas (Vicugna pacos) in Southern Peru

“…There are some previous studies focused on the genetic diversity and population structures of various south American camelids, such as alpacas, llamas, guanacos, and vicuñas [11][12][13][14][15][16][17], mainly in the regions of Peru and Bolivia. In addition, other members of the Camelidae family have been studied [18][19][20][21].…”