Title
Evaluation of Anthropogenic Threats in Yasuní National
Park and its Implications for Wild Mammal Conservation
Author(s)
Galo Zapata-Ríos, Esteban Suárez R., Víctor Utreras B., Javier Vargas O.
Published
2006
Abstract
English: Yasuní National Park is the largest protected area in Ecuador. Although extensive in area and legally protected, Yasuní in practice is virtually unprotected. The threats faced by Yasuní are numerous. Among others, they include invasion by indigenous and non-indigenous colonists, illegal timber harvesting, illegal hunting and fishing, unsustainable subsistence hunting, road construction, and oil industry activities. Unless urgent attempts are made to reduce these threats, Yasuní will succumb to increasing human pressures. Unfortunately most of the mentioned threats are not easily quantifiable because they are very dynamic and heterogeneous. Thus, effective protection for Yasuní demands that we evaluate the threats and accordingly formulate appropriate conservation actions to mitigate them. Since the distribution and intensity of human activities in Yasuní National Park have not been assessed appropriately, we developed a simple grid-based GIS model for assessing the location, extent and intensity of human activities in Yasuní Biosphere Reserve (the Biosphere Reserve includes Yasuní National Park, the Huaorani Ethnic Reserve, and a 10km buffer zone surrounding the two areas). We devised a simple binary threat index that combines several measures of disturbance and developed a threats map for the protected area. The threats map reflects several measures of disturbance such as presence of roads, deforested areas, human settlements, oil wells, and illegal logging along rivers. For assessing the accuracy of the threats map as a useful tool for understanding the impact of human activities on wildlife, we used an independent set of field data about relative abundance of medium-sized and large mammals (≥ 1kg), gathered in twelve study sites in Yasuní National Park. Mammal surveys were not stratified in relation to the threats map. The threats level and mammal relative abundance were analysed using linear regression. Our results show that threats in Yasuní National Park are concentrated in the north-western portion of the area, apparently associated with communication and transportation routes, such as rivers and oil extraction roads. On the contrary, the habitat with less impact of human activities lies in the south-eastern portion of the park, where a vast area of undisturbed forests still remains. We found a strong correlation between the human disturbance gradient showed in the threats map and mammal’s relative abundance. In some cases, the resulting correlation is negative (e.g., lowland tapir and white-lipped peccary); in other cases, the resulting correlation is positive (e.g., nine-banded armadillo, and large rodents). Based on these analyses, the grid-based GIS model represents a first step towards the establishment of habitat conservation priorities and a basis for research on the relationship of human
activities and wildlife distribution, and impacts attributable to these activities. Conservation initiatives need to be based on information about the spatial distribution of human activities across Yasuní, and the identification of areas of high-quality habitat for the long-term persistence of wildlife populations. The model provides information on wildlife habitat quality and extent, providing a measure of potential habitat for wildlife species in an area where little is known about wildlife spatial distribution, relative abundance and population densities.
Spanish: El Parque Nacional Yasuní es el área protegida más grande del Ecuador continental. Las amenazas para la conservación en el Parque Nacional Yasuní son numerosas e incluyen, entre otras, la construcción de carreteras, extracción ilegal de madera y la extracción de petróleo. Actualmente, no existe una caracterización apropiada de la distribución e intensidad de las intervenciones humanas en el Parque Nacional Yasuní, por lo que utilizamos un modelo espacial raster que incluyó variables antropogénicas para desarrollar un mapa de amenazas de Yasuní. El mapa refleja varias medidas de alteración como la presencia de carreteras, áreas deforestadas, asentamientos humanos, pozos petroleros y tala selectiva. Para evaluar la validez del mapa como una herramienta para entender el impacto de las actividades humanas en la fauna silvestre, utilizamos información independiente de campo sobre la abundancia relativa de mamíferos medianos y grandes (≥ 1kg) en doce localidades del Parque Nacional Yasuní. Los muestreos fueron aleatorios y no se diseñaron estratificadamente con relación al mapa de amenazas. Las dos fuentes de información fueron analizadas utilizando regresiones lineales. De acuerdo al mapa de amenazas, las áreas con mayor disturbio se encuentran al noroeste del parque, aparentemente concentradas a lo largo de vías de comunicación y transporte como ríos y carreteras. Por el contrario, la porción sur del Yasuní aun alberga extensos bosques con bajos niveles de amenaza. Nuestros resultados también indican que existe una fuerte correlación entre la gradiente de alteración humana presentada en el mapa y la abundancia relativa de algunas especies de mamíferos. En ciertos casos, la correlación es negativa (e.g., tapires y pecaríes) y en otros la correlación es positiva (e.g., roedores grandes). Con base en estos análisis, el mapa de amenazas representa un primer paso hacia la identificación de áreas importantes para la conservación de fauna silvestre en el Parque Nacional Yasuní.
Keywords
abundancia relativa, registros indirectos, sistemas de información geográfica, relative abundance, indirect records, geographic information systems
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PUB26337