Feeding Ecology of Propithecus diadema in Forest Fragments and Continuous Forest
Forest fragmentation is viewed as a serious threat to primates, yet whether or not it can disrupt food resources and cause energetic stress remains largely untested. I present the results of a 12-mo study of the feeding ecology of Propithecus diadema in fragmented and continuous forest at Tsinjoarivo, eastern Madagascar. Two continuous forest groups had higher dietary diversity and ate more fleshy fruit, but during the dry season, diversity was reduced and they relied heavily on mistletoe (Bakerella clavata). In contrast, 2 groups in fragments employed the lean season strategy of eating mistletoe year-round; the fruiting tree species that sustain continuous forest groups through the rainy season were largely absent. As expected, intersite dietary overlap was highest in the dry season. The level of specialization was high: fragment groups devoted 30–40% of feeding time to Bakerella clavata, compared to 28–30% in continuous forest. The major characteristic of Bakerella clavata enabling it to be an important fallback or staple resource, or both, is its extended phenology. The difference in resource utilization between sites may have important implications for nutritional status, as well as ranging and social behavior, largely owing to the small size and high abundance of feeding patches of Bakerella. Understanding resource shifts in fragments can shed light on socioecological questions by providing comparisons between continuous forest and fragment populations with differing diets and resource distributions. In addition, understanding dietary shifts in fragments can aid in species-specific conservation efforts, while contributing to a better understanding of the considerable interspecific variability of primates in responses to fragmentation.
Keywordsconservation diademed sifakas diet forest fragmentation mistletoe Propithecus diadema
I thank the Government of the Democratic Republic of Madagascar, CAFF/CORE and the Direction des Eaux et Forêts (DEF) for research authorization. Stony Brook University IACUC approved the animal capture methods. For research facilitation I thank P. Wright, B. Andriamihaja, the Malagasy Institute for the Conservation of Tropical Environments (MICET, Antananarivo), and the Institute for the Conservation of Tropical Environments (ICTE, Stony Brook: L. Donovan, F. van Berkum). I thank Margot Marsh Biodiversity Foundation, Primate Conservation, Inc., IPPL, Stony Brook University, the Earth and Space Foundation, and the National Geographic Society for providing funding and NSERC for a postdoctoral fellowship that supported manuscript preparation. For data collection assistance, I thank E. Razanadrakoto, H. Rakotoarimanana, E. Ranaivoson, J. Rakotofanala, C. Randrianarimanana, F. Ranaivomanana, J.-C. Rakotoniaina, P. Rasabo, K. Parks, T. Anderson, N. Melaschenko, J. Lapoint, E. Hatton, J. Mitchell, J. Anderson, J. Tardi, and M. Ali. Student/colleague Jean-Luc Raharison provided invaluable assistance in Madagascar, Ken Glander did the initial animal capture and training, and Karen Samonds aided throughout. Discussions with P. Wright, C. Janson, J. Fleagle, D. Doran-Sheehy, and J. Ganzhorn greatly improved the project, and the comments of C. Chapman, T. Snaith, and 3 anonymous reviewers greatly improved the manuscript.
- Begon, M., Harper, J. L., & Townsend, C. R. (1996). Ecology (3rd ed.) Oxford: Blackwell Sciences.Google Scholar
- Dehgan, A. (2003). The Behavior of Extinction: Predicting the Incidence and Local Extinction of Lemurs in Fragmented Habitats of Southeastern Madagascar. Ph.D. dissertation. Chicago: University of Chicago.Google Scholar
- Ganzhorn, J. U., Goodman, S. M., & Dehgan, A. (2003). Effects of forest fragmentation on small mammals and lemurs. In Goodman, S. M., & Benstead, J. P. (Eds.), The natural history of Madagascar (pp. 1228–1234). Chicago: University of Chicago Press.Google Scholar
- Ganzhorn, J. U., Goodman, S. M., Ramanamanjato, J.-B., Rakotondravony, D., Rakotosamimanana, B., & Vallan, D. (2000a). Vertebrate species in fragmented littoral forests of Madagascar. In Lourenço, W. R. & Goodman, S. M. (Eds.), Diversité et Endémisme à Madagascar (pp. 155–164). Paris: Societé de Biogéographie.Google Scholar
- Ganzhorn, J. U., Goodman, S. M., Ramanamanjato, J.-B., Ralison, J., Rakotondravony, D., & Rakotosamimanana, B. (2000b). Effects of fragmentation and assessing minimum viable populations of lemurs in Madagascar. In Rheinwald, G. (Ed.), Isolated Vertebrate Communities in the Tropics (pp. 265–272). 4th International Symposium, Bonn.Google Scholar
- Gilbert, K. A., & Setz, E. Z. F. (2001). Primates in a fragmented landscape: Six species in central Amazonia. In Bierregaard, R. O., Jr., Gascon, C., Lovejoy, T. E., & Mesquita, R. C. G. (Eds.), Lessons from Amazonia: The ecology and conservation of a fragmented forest (pp. 262–270). New Haven: Yale University Press.Google Scholar
- Hemingway, C. A. (1995). Feeding and Reproductive Strategies of the Milne-Edwards’ Sifaka, Propithecus diadema edwardsi, Ph.D. dissertation, Durham, North Carolina: Duke University.Google Scholar
- Irwin, M. T. (2006a). Ecological Impacts of Forest Fragmentation on Diademed Sifakas (Propithecus diadema) at Tsinjoarivo, Eastern Madagascar: Implications for Conservation in Fragmented Landscapes. Ph.D. dissertation, New York: Stony Brook University, Stony Brook.Google Scholar
- Irwin, M. T. (2006b). Ecologically enigmatic lemurs: The sifakas of the eastern forests (Propithecus candidus, P. diadema, P. edwardsi, P. perrieri and P. tattersalli). In Gould, L., & Sauther, M. (Eds.), Lemurs: Ecology and adaptation (pp. 305–326). New York: Springer.Google Scholar
- Irwin, M. T. (2007b) Diademed sifaka (Propithecus diadema) ranging and habitat use in continuous and fragmented forest: Higher density but lower viability in fragments? Biotropica DOI 10.1111/j.1744-7429.2007.00368.x.
- Irwin, M. T., Glander, K. E., Raharison, J.-L., Samonds, K. E. (2007). Effect of habitat and sex on body mass and morphometrics of diademed sifakas (Propithecus diadema). American Journal of Physical Anthropology ,132, (S44):134.Google Scholar
- Marsh, L. K. (2003). Primates in fragments: Ecology and conservation. New York: Kluwer.Google Scholar
- Medley, K. E. (1993). Extractive forest resources of the Tana River National Primate Reserve, Kenya. Economic Botany, 47, 171–183.Google Scholar
- Meyers, D. M. (1993). The Effects of Resource Seasonality on Behavior and Reproduction in the Golden-Crowned Sifaka (Propithecus tattersalli, Simons, 1988) in Three Malagasy Forests. Ph.D. dissertation, Durham, North Carolina: Duke University.Google Scholar
- Meyers, D. M., & Wright, P. C. (1993). Resource tracking: Food availability and Propithecus seasonal reproduction. In Kappeler, P. M., & Ganzhorn, J. U. (Eds.), Lemur social systems and their ecological basis (pp. 179–192). New York: Plenum Press.Google Scholar
- Powzyk, J. A. (1997). The Socio-ecology of Two Sympatric Indriids: Propithecus diadema diadema and Indri indri, a Comparison of Feeding Strategies and Their Possible Repercussions on Species-Specific Behaviors. PhD dissertation, Durham, North Carolina: Duke University.Google Scholar
- Siegel, S., & Castellan, N. J., Jr., (1988). Nonparametric statistics for the behavioral sciences. New York: McGraw-Hill.Google Scholar
- Terborgh, J. (1986). Keystone plant resources in the tropical forest. In Soulé, M. E. (Ed.), Conservation biology: The science of scarcity and diversity (pp. 330–344). Sunderland: Sinauer.Google Scholar
- Umapathy, G., & Kumar, A. (2000b). Impacts of the habitat fragmentation on time budget and feeding ecology of lion-tailed macaque (Macaca silenus) in rain forest fragments of Anamalai Hills, south India. Primate Report, 58, 67–82.Google Scholar
- von Ende, C. N. (2001). Repeated-measures analysis: Growth and other time-dependent measures. In Scheiner, S. M. & Gurevitch, J. (Eds.), Design and analysis of ecological experiments (pp. 134–157). Oxford: Oxford University Press.Google Scholar