Last of the wild revisited: assessing spatial patterns of human impact on landscapes in Southern Patagonia, Chile

Human activities are continuously expanding at a global scale and having an increasing effect on the remaining natural ecosystems in remote areas, such as the Magellan Region of southern Patagonia, Chile. In addition to extensive livestock holdings, aquaculture and tourism are advancing into formerly undisturbed areas, and insufficient information on the spatial scope and intensity of these alterations is available to inform and support conservation policies. The aim of this study was to spatially analyse the degree, scope and spatial distribution of anthropogenic alterations. Accordingly, two spatially explicit indexes, the degree of anthropogenic alteration (DAA) and human influence index (HII), have been applied. The results show a significant spatial overestimation of the remaining undisturbed natural areas. Despite low population densities and extensive conservation designations, a major share of the total area has been anthropogenically altered. Depending on the measure type, between 53.1 % (DAA) and 68.1 % of the area (HII) needs to be considered as influenced by human activity in some way. Our findings challenge previous studies by the Wildlife Conservation Society (WCS and CIESIN in Last of the wild project, version 2, 2005 (LWP-2): last of the wild dataset (Geographic), NASA socioeconomic data and applications center (SEDAC), Palisades, 2005). Their worldwide assessment of pristine natural environments indicated that a much smaller part of the Magellan region has been subject to human influence. The chosen methodologies represent an opportunity to detect and monitor human influence at small spatial scales, which has heretofore remained unnoticed. Because such alterations are becoming more frequent in remote regions, the assessment approaches presented here provide important information on human-environment interactions to support land-use and nature conservation policy design. In addition, small-scale structures and different types of economic activities are considered to support policies that can protect the remaining natural areas from human encroachment. Moreover, implications of the proposed methodology for biodiversity conservation policy are discussed.