C1 - Effects of land use on diversity and structure of vertebrate communities

Summary

Research in STORMA C1 focused on the ecology of two primate species (Macaca tonkeana and Tarsius dianae), the bird community and the status of larger wildlife species (Anoa, Babirusa, Maleo and Red Junglefowl) in the Lore Lindu National Park. Fragmentation and habitat loss at low elevations was studied to evaluate conservation prospects for forestdependent species. To study direct effects of land use, radio-tracking methods (Tarsius), as well as behavioural observations (Macaca), mist netting (understorey birds) and point sampling (birds) in natural forest and various land use types (e.g. secondary forest, agroforestry systems, annual cultures) were used. Indirect effects of land use were studied by analysing food abundance (insects, fruits) and (artificial) nest predation experiments. Recall information from questionnaire surveys (project A3) was used to evaluate the population status of larger wildlife (Anoa, Babirusa, Maleo, Junglefowl, Macaques). Habitat fragmentation was studied using remote sensing data, elevation models and available information on altitudinal ranges of bird species. Quantitative comparisons with Borneo show that the structure of Sulawesi's bird communities differs substantially from continental areas in species richness, abundance and guild composition. Hypotheses on the causes of potential density compensation and habitat expansion of related taxa were developed. Many bird species were able to colonize secondary forest habitats (forest gardens with natural canopy, logged forest) in high numbers at preferred elevations and resource abundance in those habitats was not necessarily lower than in natural forest. However, in the case of birds, the long-term capability to survive in disturbed situations might be questionable since levels of nest predation were found being markedly increased compared to natural forest. Artificial agroforestry systems with Gliricida-shade trees and annual cultures did not support Sulawesi’s endemic wildlife. Questionnaires revealed that populations of larger wildlife (Anoa, Babirus) and birds (Maleo, Red Junglefowl) declined in the study area (Lore Lindu National Park) over the last ten years, even local extinction was reported from certain villages. The availability of lowland and hill forest habitat in the Lore Lindu National Park is severely reduced by ongoing deforestation. Our analysis shows that deforestation in - and even outside the Park - threatens half of the Park’s resident bird species by extinction since more than 90 of its species are confined to elevations below 1200 m.