Population Size and Characteristics of Alouatta pigra Before and After a Major Hurricane
- 283 Downloads
Although some environmental risks and resources are known to affect the evolution of primate social groups, we know little about the effect of major natural disturbances on primate populations. Hurricane Iris hit the Monkey River watershed in southern Belize in October 2001, presenting a unique opportunity to document the effects of a natural disaster under circumstances wherein some pre-hurricane data were available. We measured the characteristics of the population of black howlers in the affected forest 3.5 years after the storm and compared the population data with pre-hurricane data from a 52-ha study area, that may represent the larger continuous riverine forest and from which all monkeys were known. From February to May 2004, we sampled 28.77 km2 of the 96-km2 forest fragment via five transects walked 12 times each. From these data we estimate that the population in the watershed has dropped from 9784 to 1181 monkeys, a reduction of 88%, reflected by both a 79% drop in the number of social groups and a 38% reduction in group size. Before the storm, 75% of the social groups were multimale; after the storm, 74% of the groups were unimale. While the ratio of adult females to males improved slightly, the ratio of adults to immatures, and adult females to immatures more than doubled, indicating a much lower potential for growth. These data provide a quantitative assessment of how a major natural disturbance can affect a primate population.
KeywordsAlouatta pigra group size hurricane local extinction natural disturbance population density population growth
We would like to thank the people of Monkey River for their help throughout this project and especially to our forest guides, as well as Tracy Wyman and Aaron Osicki for maps and Shelley Alexander for satellite images and for their assistance with all the mapping aspects of this project. We are grateful to all of the researchers who helped with the data collection, including Allison Maclean, Greg Bridgett, and Alison Behie, and to Linda Fedigan and Colin Chapman for helpful discussions regarding the framework of the paper. We would like to acknowledge our funding sources, including the Department of Anthropology, Faculty of Social Sciences, and University Research Grants Committee at the University of Calgary, Province of Alberta Graduate Scholarship, National Geographic, and Natural Sciences and Engineering Research Council of Canada Post Graduate Scholarship and Discovery Grant Programs. Finally, the manuscript was greatly improved by helpful comments by two anonymous reviewers.
- Alexander, S. M., Pavelka, M. S. M., & Bywater, N. H. (2006). Quantifying fragmentation of black howler (Alouatta pigra) habitat after Hurricane Iris (2001), Southern Belize. In A. Estrada, P. A. Garber, M. S. M. Pavelka, & L. Luecke (Eds.), New perspectives in the study of Mesoamerican primates: Distribution, ecology, behavior, and conservation (pp. 539–561). New York: Springer.CrossRefGoogle Scholar
- Crockett, C. M., & Eisenberg, J. F. (1987). Howlers: Variations in group size and demography. In B. B. Smuts, D. L. Cheney, R. M. Seyfarth, R. W. Wrangham, & T. T. Struhsaker (Eds.), Primate societies (pp. 54–68). Chicago and London: The University of Chicago Press.Google Scholar
- Heltne P. G., Turner D. C., & Scott, N. J., Jr. (1975). Comparison of census data on Alouatta palliata from Costa Rica and Panama. In R. W. Thorington Jr., & P. G. Heltne (Eds.). Neotropical primates: field studies and conservation (pp. 10–19). Washington D.C.: National Academy of Sciences.Google Scholar
- Horwich, R. H., Brockett, R. C., James, R. A., & Jones, C. B. (2001). Population growth in the Belizean black howling monkey (Alouatta pigra). Neotropical Primates, 9, 1–7.Google Scholar
- Horwich, R. H., & Johnson, E. D. (1986). Geographical distribution of the black howler (Alouatta pigra) in Central America. Primates, 27, 53–62.Google Scholar
- Meerman, J. (2001). A first assessment of damage to terrestrial ecosystems in southern Belize as caused by hurricane Iris of October 8, 2001. Belize Environmental Consultancies Limited, Belize District, Belize.Google Scholar
- National Oceanic & Atmospheric Administration. (2007). http://www.noaa.gov/.
- Pavelka, M. S. M. (2003). Group, range, and population size of Alouatta pigra at Monkey River, Belize. Neotropical Primates, 11, 187–191.Google Scholar
- Pavelka, M. S. M., & Chapman, C. A. (2006). Population structure of black howlers (Alouatta pigra) in southern Belize and responses to hurricane Iris. In A. Estrada, P.A. Garber, M. S. M. Pavelka, & L. Luecke (Eds.), New perspectives in the study of mesoamerican primates: Distribution, ecology, behavior, and conservation (pp.143–163). New York: Springer.CrossRefGoogle Scholar
- Ratsimbazafy, J. H. (2002a). On the brink of extinction and the process of recovery: Responses of black-and-white ruffed lemurs (Varecia variegata variegata) to disturbance in Manombo Forest, Madagascar. Dissertation Abstracts International.Google Scholar
- Ratsimbazafy, J. H., Ramarosandratana, H. V., & Zaonarivelo, R. J. (2002). How do black-and-white ruffed lemurs still survive in a highly disturbed habitat? Lemur News, 7, 7–10.Google Scholar
- Rivera, A., & Calme, S. (2006). Forest fragmentation and its effects on the feeding ecology of black howlers (Alouatta pigra) from the Calakmul area in Mexico. In A. Estrada, P. A. Garber, M. S. M. Pavelka, & L. Luecke (Eds.), New perspectives in the study of Mesoamerican primates: Distribution, ecology, behavior, and conservation (pp. 189–215). New York: Springer.CrossRefGoogle Scholar
- Rodriguez-Toledo, E. M., Mandujano, S., & Garcia-Orduna, F. (2003). Relationships between forest fragments and howler monkeys (Alouatta palliata mexicana) in southern Veracruz, Mexico. In L. K. Marsh, (Ed.), Primates in fragments: Ecology and conservation (pp. 79–96). New York, Boston, Dordrecht, London, Moscow: Kluwer Academic/Plenum Publishers.Google Scholar
- Rylands, A. B., Groves, C. P., Mittermeier, R. A., Cortes-Ortiz, L., & Hines, J. J. H. (2006). Taxonomy and distributions of Mesoamerican primates. In A. Estrada, P. A. Garber, M. S. M. Pavelka, & L. Luecke (Eds.), New perspectives in the study of Mesoamerican primates: Distribution, ecology, behavior, and conservation (pp. 29–81). New York: Springer.CrossRefGoogle Scholar
- Van Belle, S., & Estrada, A. (2006). Demographic features of Alouatta pigra populations in extensive and fragmented forests. In A. Estrada, P. A. Garber, M. S. M. Pavelka, & L. Luecke (Eds.), New perspectives in the study of Mesoamerican primates: distribution, ecology, behavior, and conservation (pp. 121–143). New York: Springer.CrossRefGoogle Scholar
- Zunino, G. E., Gonzalez, V., Kowalewski, M. M., & Bravo, S. P. (2001). Alouatta caraya. Relations among habitat, density and social organization. Primate, Report, 61, 37–46.Google Scholar