Diversity and habitat use of medium-large sized mammals across oil palm landscapes in the Llanos region of Colombia

Abstract

Rising demand for products derived from oil palm has resulted in accelerated expansion of its global cropping area. In Southeast Asia, where most of world's oil palm is produced, forest loss due to oil palm cultivation has become one of the major threats to biodiversity. As reviewed in Chapter 1, oil palm is now rapidly expanding in Latin America, where Colombia is the largest oil palm producer with nearly 500,000 ha currently under cultivation. Although most oil palm expansion in Colombia has taken place on partially degraded lands or in areas previously used for crops or livestock, little is known about the biodiversity that currently exists in these landscapes and the effect that expanded oil palm agriculture will have. Because Colombia is one of the world's most biodiverse countries, understanding how oil palm production affects wildlife communities is vital to inform conservation planning and improve land-management practices. In this thesis, I used mammal species as a focal group to evaluate how fauna have responded to expanding oil palm production in Colombia. Mammals are a diverse group and, as such, are good indicators of ecosystem degradation. This is because mammals occupy a wide range of ecological niches, have important and varied roles at a range of different trophic levels, and are often vulnerable to habitat fragmentation. I conducted this study in the rural areas surrounding the towns of Restrepo, Cumaral, Cabuyaro, Acacias, Castilla la Nueva, and San Carlos de Guaroa, in the Department of Meta, in the eastern plains or Llanos Orientales region of Colombia. This region, which has become the largest oil palm-production zone in the country, is a seminatural savanna ecosystem interspersed by riparian forests of differing sizes and ages along rivers and streams and human land uses such as grazing and agriculture. Within this study area, I used unbaited, automatic camera traps at 56 sites located each at least 2 km apart (33 sites in oil palm plantations and 23 in riparian forest), spanning a total area of ~2,000 km² (194‒394 m.a.s.l.) to detect terrestrial medium- and large-sized mammals (>0.5 kg). In the Llanos region, knowledge of the ecology and distribution of most terrestrial mammals is very limited. Therefore, I used multiple approaches (as described below) to address these gaps and understand the responses of mammals to oil palm plantations and other local- and landscapelevel environmental factors in the Colombian Llanos. First, in Chapter 2, I examined how species richness, abundance and composition of terrestrial mammal species differed between oil palm plantations and riparian forests. I also determined the influence of landscape- and habitat-level features on those metrics. Data from 12,403 camera-days revealed that species richness and the community-level composition of mammals differed significantly between oil palm and riparian forest, with site-level richness in oil palm plantations being 47% lower, on average, than in riparian forests. Within plantations, mammalian species…