Occupancy of Terrestrial Mammal Species of the Madeira-Purus Interfluvium in Amazonas, Brazil

Author

Rebecca J. Lyon, Southern Illinois University CarbondaleFollow

Date of Award

5-1-2017

Degree Name

Master of Science

Department

Forestry

First Advisor

Nielsen, Clayton

Abstract

The Amazon represents more than half of the surviving tropical forest on Earth. However, despite its vast size and diversity, habitat loss is an increasing threat due to the growth of economic activities and infrastructure projects. Carnivores play an important role in reducing herbivore numbers through predation, thereby reducing the risk of over browsing and are particularly susceptible to habitat loss and fragmentation due to their large area requirements, low densities, and slow population growth. Altering herbivore communities via a change in carnivore density and habitat loss may change plant diversity by altering seed dispersal, and seed and seedling survival. The Madeira-Purus interfluvial plain in Brazil is a pristine and yet understudied part of the Amazon. I studied environmental factors affecting occupancy and detection of carnivores and herbivores in the Madeira-Purus interfluvial plain Amazonas state, Brazil. During 2010-12 remote cameras were used to investigate patterns of site occupancy and detection probabilities, as affected by habitat and anthropogenic influences, for several terrestrial mammal groups. Site occupancy and detection varied for all species groups across land protections types. Medium felids and peccaries showed a sharp decline in occupancy from unprotected lands to state-protected sites with the highest occupancy on the federally-protected site. Brocket deer increased in occupancy from unprotected to state-protected lands, and from state-protected to federally-protected lands. Large felid occupancy, however, was exactly the opposite, with the lowest occupancy at the federally-protected site. Species richness at camera sites was the most important covariate, positively influencing occupancy in all species groups. This helps inform wildlife management by providing suggestions to improve future occupancy studies and support for maintaining protected areas for the persistence of viable mammal populations. I found occupancy of many species groups (i.e. peccaries, medium felids and medium rodents) were lowest on state-protected land. Species richness was also lowest on state-protected land, implying a depletion of herbivore and carnivore species in that area, which may be due to local foraging and hunting of forest resources by humans. I recommend stricter laws and enforcement to limit the harvest of forest fruits and nuts and illegal hunting. Repaving local highways will likely increase human influence in these areas and increase pressure on forest resources.