The 82nd Annual Meeting of the American Association of Physical Anthropologists (2013)

Is the fit right? Lemur species-area curves in a fragmented landscape


Department of Anthropology, University of Toronto

Saturday 9:00-9:15, 200ABC Add to calendar

Habitat fragmentation continues to increase in Madagascar. The 2012 IUCN Red List reports 91% of lemur species are now threatened. Determining how lemurs respond to habitat fragmentation is critical to improve conservation efforts. Documenting species-area relationships in Madagascar will allow us to determine how species richness is impacted by alterations in habitat size.

In forest fragments, the species-area relationship is expected to follow a sigmoidal pattern with an upper asymptote. The shape of the sigmoidal curve is due to the total number of species (upper asymptote) and the small island effect, where species richness is affected by factors other than area, creating a j-shape in the lower portion of the curve. However, most studies have fitted data using the power model which does not have an asymptote or account for the small island effect.

The objective of our study is to determine how habitat fragmentation affects lemur species richness. We surveyed 42 forest fragments ranging in size from 0.23 ha to 117.70 ha on the western edge of Ankarafantiska National Park, Madagascar. The landscape is characterized by homogeneous stands of tropical deciduous dry forest surrounded by savannah. We found six out of the eight potential species and fitted five species-area models to our data using non-linear least squares regression analysis. Using Akaikes information criterion we determined that the power model rather than candidate sigmoidal models best fit the data. This study will determine minimum fragment sizes needed to preserve the majority of lemur species.

This project was funded by the Government of Ontario, The Explorers Club Exploration Fund, University of Toronto School of Graduate Studies Travel Grant, and the American Society of Primatologists Conservation Committee Small Grant.

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