Date of Award
Master of Arts (MA)
Herbert H. Covert
Madagascar is one of the top global hotspots for biodiversity (Yoder & Nowak, 2006). Yet it is experiencing high rates of habitat loss, especially gallery forest, an important resource to many endemic primate species (Sauther et al., 1999; Sussman & Rakotozafy, 1994). Natural disasters such as Madagascar's cyclical droughts and cyclones may compound the effects of habitat loss (Gould et al., 1999; Whitelaw, 2010; Wright, 1999). Changes in dietary ecology as a result of these events may be reflected in altered hair δ13C and δ15N values from the study population. By studying how lemurs respond to cyclone and drought habitat disturbance, researchers can better understand how forest destruction and non-native species introduction by humans might impact the ability of lemurs to effectively react for continued survival.
This study looks at the effects of habitat disturbance on four endemic Malagasy ring-tailed lemur troops via stable carbon and nitrogen isotope values of hair samples collected between 2003-2006. Severe droughts affected the region in 2004 and 2006. In January 2005, cyclone Ernest hit southwestern Madagascar causing widespread defoliation, tree falls, and a decrease in food availability (Whitelaw, 2010).
δ13C and δ15N values shifted in a non-uniform pattern based on both troop and year. This suggests ring-tailed lemur dietary strategies may vary between troops and depending on what environmental effects are present. During normal years, troops may compete over highly desirable resources. During a drought, they may focus on a few less preferred but abundant resources, reducing their dietary diversity. After a cyclone, the drought resistant resources may no longer be widely available, increasing intra-troop competition and requiring ring-tailed lemurs to broaden their dietary diversity. Because they are synchronous group feeders (Sauther et al., 1999), a low availability of any single resource may require them to also increase dietary diversity within the troop, forcing individuals to utilize different types of resources. This explanation is one possible interpretation supported by the δ13C and δ15N values presented in this thesis.
Schwagerl, Kristin Lilla, "The Dietary Ecology of Ring-Tailed Lemurs As Reflected By δ13C and δ15N Stable Isotope Values" (2015). Anthropology Graduate Theses & Dissertations. 46.