Nature representation in South American protected areas: country contrasts and conservation priorities

BALDI, GERMÁN; SCHAUMAN, SANTIAGO; TEXEIRA, MARCOS; MARINARO, SOFÍA; MARTIN, OSVALDO A.; GANDINI, PATRICIA; JOBBÁGY, ESTEBAN G.

PeerJ

Peerj

Año: 2019 vol. 7

Background. South America faces strong environmental pressures as a result ofagriculture and infrastructure expansion and also of demographic growth, demandingimmediate action to preserve natural assets by establishing protected areas. Currently,7.1% of the (sub)continent is under strict conservation categories (I to IV, IUCN), butthe spatial distribution of these 1.3×106km2is poorly understood. We evaluated therepresentation of nature within the networks of protected areas, map conservation pri-orities and assess demographic, economic or geopolitical causes of existing protectionpatterns.Methods. We characterized nature representation by looking at two components:the extent and the equality of protection. The first refers to the fraction of territoryunder protection, while the second refers to the homogeneity in the distribution alongnatural conditions of this protected fraction. We characterized natural conditionsby either 113 biogeographical units (specifically, ecoregions) or a series of limitedand significant climatic, topographic and edaphic traits. We analyzed representationevery ten years since 1960 at national and continental levels. In the physical approach,histograms allowed us to map the degree of conservation priorities. Finally, we rankedthe importance of different economic or geopolitical variables driving the observeddistributions with a random forest technique.Results. Nature representation varied across countries in spite of its priority in con-servation agendas. In Brazil, Peru and Argentina there are still natural conditions withno formal protection, while in Bolivia and Venezuela, protected areas incorporate thenatural diversity in a more balanced manner. As protected networks have increased theirextent, so did their equality across and within countries over time. Our maps revealedas top continental priorities the southern temperate, subhumid and fertile lowlandenvironments, and other country-specific areas. Protection extent was generally drivenby a low population density and isolation, while other variables like distance to frontiers,were relevant only locally (e.g., in Argentina).