SCARCE SEASON DIET AND KEYSTONE RESOURCES IN THREE BROWN LEMUR (EULEMUR FULVUS SSPP.) POPULATIONS |
| S. Johnson and D. Overdorff Department of Anthropology, University of Texas at Austin, Austin, TX, 78712, USA |
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| Madagascar is known for its low diversity of frugivores. Factors suggested to explain this phenomenon include low, unpredictable fruit production and lack of keystone resources (particularly Ficus). We investigated phenology and feeding behavior in three populations of brown lemurs (the most common mammalian frugivore). We examined variability across sites and populations within the southeast rain forest region. Phenological patterns were similar across sites, with low fruit production during the cool, dry season. In addition, overall feeding profiles were similar throughout the region. Fruit accounted for the majority of feeding time (66-91%), with lesser reliance on leaves and flowers. However, two populations demonstrated a marked shift towards possible keystone resources during winter months. Eulemur fulvus from Andringitra spent up to 81% of monthly feeding time consuming Ficus while brown lemurs at Vevembe specialized on Pandanus flowers (37%). Ranomafana brown lemurs did not rely on either of these resources; however, they are known to migrate during low productivity, likely to consume Psidium fruits. These results underscore the heterogeneity of rain forest productivity and community ecology. Furthermore, they point to the potential importance of Ficus as a keystone resource. The availability of this food source may explain the very high population density of brown lemurs at Andringitra. With little evidence for the prevalence of Ficus elsewhere in the region, Andringitra may be the exception that proves the rule. |
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