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

Abstract

Humans arrived in the Patagonia region of southern South America in the late Pleistocene period, ca. 15,000 years ago. A few centuries later, during a period of rapid warming, the megafauna went extinct in Patagonia, as well as some smaller species, like the guanaco (Lama guanicoe), in the southern portion of the region. As in other regions, extinctions probably occurred due to a combination of effects of climate and direct and indirect impacts of humans on wildlife communities. We reviewed recent archeological and genetic-based discoveries about numbers and distributions of humans and wildlife and their early interactions and used them to draw lessons for current debates among managers and scientists. Recent discoveries, for example, help us understand (1) the population limitation mechanisms and other interactions involving guanacos, livestock, forage, predators, and scavengers; (2) the magnitude of wildlife movements and the need for landscape-level planning for conservation; (3) the importance of indirect effects of human activities on wildlife communities; and (4) the compounded effects of human activities and climate change on wildlife. We believe these lessons drawn from deep time and recent history can help define new priorities for research and management and inform our conservation vision for the 21st century, a period when dramatic climate change impacts will add challenges to a region subject to a century of overgrazing and other anthropogenic pressures.

Drivers of habitat availability for terrestrial mammals: Unravelling the role of livestock, land conversion and intrinsic traits in the past 50 years

“…While sheep density was not a significant variable in our models, we recognize that the presence of sheep in several regions of the world negatively affected the distribution of many terrestrial mammals. In Patagonia, guanaco ( Lama guanicoe ) populations were extirpated from most of their range by the booming of sheep industry and recovered only when sheep ranching collapsed in the second half of the 20th century (Novaro & Walker, 2021). In Africa and Arabia, sheep ranching led to competition with wild herbivores, both through direct means such as food removal and indirectly through habitat degradation and loss (Keesing & Young, 2014).…”

Cabo Dos Bahías y el manejo del guanaco en la Patagonia argentina

“…La explicación más frecuente en publicaciones y documentos que citan el colapso de C2B es la falta de mecanismos de regulación poblacional como, por ejemplo, la ausencia de depredadores, la interrupción de supuestos procesos migratorios, la falta de manejo extractivo o el contraste de manejo con el establecimiento lindero. Esto habría inducido un exceso poblacional respecto de la capacidad de carga de la reserva que -implícita o explícitamente según la fuente-deterioró el recurso forrajero de tal forma que la población colapsó por falta de alimento (Walker et al 2004;Cévoli 2005;Baldi et al 2006;Bolgeri 2016;SGAYDS 2019;Oliva et al 2020a;Novaro and Walker 2021). A pesar de que el carácter excepcional del área debido a su pequeña superficie y su perímetro de dispersión acotado por el mar ha sido resaltado en muchas oportunidades, es llamativo el nivel de extrapolación y generalización a otros entornos ecológicos en algunas de estas publicaciones.…”

“…Al citar el colapso de C2B se suele asumir que los guanacos de LaPla no están sometidos al nivel de competencia que opera en la reserva por presentar densidades de guanacos más bajas y no haber registros de mortalidad masiva (Cévoli 2005). Además, se considera que los guanacos habrían sido perseguidos fuera de LaPla y obligados a permanecer dentro de la reserva C2B, aumentando artificialmente la densidad de esta última (Novaro and Walker 2021). LaPla presenta una carga ovina de 30 UGO/km 2 , lo que complejiza la estimación del nivel de competencia operando sobre la población de guanacos ya que los ovinos desplazan competitivamente al guanaco (Marino and Rodríguez 2022).…”

Review of Historical and Zooarchaeological Data to Trace Past Biogeographic Distribution of Endangered Huemul (Hippocamelus bisulcus) to Enhance Conservation Strategies

“…For some areas, it is well documented that past hunting of huemuls was also aimed at trading their products, including skins which reached Europe. Thus, if past hunting resulted in strong declines and local extinctions of guanacos (by 91-98% [129]), although much more difficult to hunt than huemuls, it is likely that huemuls were locally extirpated even faster. Similarly, the human colonization of the Andean valleys in modern times added additional pressures, which further exasperated the impact, and probably caused further local eliminations of huemul within decades.…”

“…Distribution maps show sheep occurring throughout most of these areas, whereas cattle presence is more restricted, but still substantial [173]. For instance, extensive sheep ranching in arid Patagonia started late in the 19th century, reaching 50 million heads [129], aside from more than 200,000 cattle and millions of native guanacos (Figure 2). This capacity of these plains to sustain a large biomass of wild and domestic ungulates is based on the immense geohydrological system containing several rivers that empty into the Atlantic Ocean (Figure 1).…”