Pathways of megaherbivore rewilding transitions: typologies from an Andean gradient

H Ricardo Grau,Ezequiel Aráoz,Carlos J Navarro,A Sofía Nanni,Agustina Malizia,Alastair Iles

doi:10.1525/elementa.415

H Ricardo Grau, Ezequiel Aráoz + Show 4 more

Open Access

https://doi.org/10.1525/elementa.415

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Abstract

In most of the planet, large herbivore communities have been replaced by livestock, but this process is reversing in many places. Here, we outline and review the pathways of “megaherbivore rewilding transitions” in three social-ecological-systems of subtropical Argentina. In the extensive arid high-elevation Puna plateau we observed a “rapid rewilding pathway” where the reduction of livestock was accompanied by the recovery of native camelid populations from near extinction in a few decades. In the forest-grassland ecotone, decreasing livestock favored higher fire frequency, probably limiting the speed of native herbivore recovery in an “increasing fire pathway”. In lowland montane forests, the recovery of native herbivore communities appears to be lagged by fragmentation, local extinctions and human pressure, representing a case of “connectivity-limited rewilding”. These typologies exemplify the complexity of outcomes resulting from livestock diminishing density, and provide a framework to understand and optimize processes of large herbivore rewilding according to different social-ecological contexts.

Highlights

Human land use is a major component of global environmental dynamics
By analyzing spatial patterns of vegetation, land science has largely focused on research questions in which land use is mostly reflected in land cover
Research initially focused on deforestation as the main land change process; and later looked at “forest transition” processes of forest recovery in originally forest-dominated regions or countries

Summary

Introduction

Human land use is a major component of global environmental dynamics. By analyzing spatial patterns of vegetation, land science has largely focused on research questions in which land use is mostly reflected in land cover. The region is mostly unsuitable for croplands due to arid conditions (Grau, 2018), for which historical human impacts did not imply major habitat fragmentation, and wildlife populations were able to persist in the extensive and well connected remote places far from human settlements (Wursten et al, 2014) This pattern facilitated recolonization: from the verge of extinction, the population of vicuñas went from a few thousands in the 1960s to more than 120,000 in the onset of the 21st century (Izquierdo et al, 2018), due to a combination of decreasing incentives for conventional livestock (as local production cannot compete with modern production systems in the lowlands, and access to “imported” food and fibers has increased through commerce), replacement of equines by vehicles as a mean of transportation, rural population decline, protective laws prohibiting hunting, Art. 19, page 3 of 12 and incentives to produce high quality wool from vicuñas in semi-captivity (Vila et al, 2018) probably the only case here analyzed where the rewilding process has a direct economic benefit. Different native and nonnative plant species may take advantage of the window of opportunity to increase plant biomass provided by reduced herbivory pressure

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Discussion

Conclusions