Demographic Structure of Zanzibar Red Colobus Populations in Unprotected Coral Rag and Mangrove Forests
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More than half of the global population of the endangered Zanzibar red colobus (Procolobus kirkii) live outside the single major protected area on Zanzibar Island. We present data on the 2 largest, discrete subpopulations living in unprotected areas at extremes of the species’ range. We compare the size and structure of 11 groups, specifically 6 core groups inhabiting interior, mature forest with 5 peripheral groups living in disturbed/degraded edge habitats. Groups living in southern mangrove forest—a species-poor but more productive and less seasonal habitat than coral rag thicket—had larger group sizes and more heterogeneous age structure, were more stable, and had higher rates of infant survival than did groups in northern coral rag. Group size ranged from 5.5 ± 1.6 SD (the smallest reported for this species) in edge coral rag to 31.2 + 1.9 SD in core mangroves. Edge groups were significantly smaller than core groups in northern coral rag while in the south, where all groups had access to mangroves, we found no significant difference in mean group size between edge and core areas. Groups using mangroves exhibited frequent social play, an indicator of habitat quality, and had a higher ratio of births per female per year. We suggest that mangroves are an important refuge and possibly source habitat for Zanzibar red colobus. We urge the conservation of mangrove and remaining coral rag in the unprotected areas described here in an effort to sustain this endemic species throughout its range.
KeywordsHabitat fragmentation Local extinction risk Mangrove Procolobus Refuge
We thank the Department of Commercial Crops, Fruits and Forestry (DCCFF) in Zanzibar and its Director, Dr. Bakari Asseid, for support of and permission to conduct this study. For assistance in the field, we thank Aliy Abdul Rahman, Duncan Gillespie, Kirstin Siex, Mtumwa Simai, Iss-haka Hussein Abdulla, and Mwinyi Khamis Mwinyi. We thank the editors Joanna Setchell and Oliver Schülke and 2 anonymous reviewers for helpful comments on our manuscript. Thank you to Joanna Nowak for help with the study site map. K. Nowak’s fieldwork was supported by the Wildlife Conservation Society, Leakey Foundation, Primate Conservation, Inc., American Society of Primatologists, and the Leakey Trust. The monitoring of the groups in this study has continued since 2005 as part of the WCS-Zanzibar Program.
- Bhagwat, S. A., Willis, K. J., Birks, H. J. B., Whittaker, R. J. (2008). Agroforestry: a refuge for tropical biodiversity? Trends in Ecology and Evolution, 23, 261–267.Google Scholar
- Buckland, S. T., Anderson, D. R., Burnham, K. P., Laake, J. L., Borchers, D. L., & Thomas, L. (2001). Introduction to distance sampling: Estimating abundance of biological populations. Oxford: Oxford University Press.Google Scholar
- Camperio Ciani, A., Palentini, L., & Finotto, E. (2001). Survival of a small translocated Procolobus kirkii population on Pemba Island. Animal Biodiversity and Conservation, 24, 15–18.Google Scholar
- Daniel, W. W. (1990). Applied nonparametric statistics (2nd ed.). Boston: PWS-Kent.Google Scholar
- Dunbar, R. I. M. (1988). Primate social systems. London: Croom Helm.Google Scholar
- Field, A. (2005). Discovering statistics using SPSS (2nd ed.). London: Sage.Google Scholar
- Larsen, D. R. (1997). Natural resource biometrics. URL: http://oak.snr.missouri.edu/nr3110/.
- Marshall, A. R. (2007). Disturbance in the Udzungwas: Responses of monkeys and trees to forest degradation. Ph.D. thesis, University of York, York, UK.Google Scholar
- Masoud, T. S., Finnie, D., Omar, A. B., Basha, A. U., & Wild, R. G. (2003). Zanzibar red colobus conservation strategy — a long term strategy for the survival of the Zanzibar red colobus. Forestry Technical Paper 137. Zanzibar: Department of Commercial Crops, Fruits, and Forestry.Google Scholar
- Mease, L. (2009). Survey of anthropogenic vegetation changes on Uzi and Vundwe Islands: A study on deforestation and its implications for people and wildlife. Unpublished report for School for International Training. ISP Collection, Paper 758. URL: http://digitalcollections.sit.edu/isp_collection/758.
- Mturi, F. A. (1991). The feeding ecology and behavior of the red colobus monkey (Colobus badius kirkii). Ph.D. thesis, Dar es Salaam: University of Dar es Salaam, Tanzania.Google Scholar
- Nowak, K. (2007). Behavioral flexibility and demography of Procolobus kirkii across floristic and disturbance gradients. Ph.D. thesis, University of Cambridge, UK.Google Scholar
- Nowak, K., Perkin, A., & Jones, T. (2009). Update on habitat loss and conservation status of the endangered Zanzibar red colobus on Uzi and Vundwe Islands. Unpublished report for Department of Commercial Crops, Fruits and Forestry, Zanzibar. URL: http://www.primate.org/publications.htm.
- Siex, K. S. (1995). The Zanzibar red colobus monkey (Procolobus kirkii): Ecology, demography, and use of Cocos nucifera. Master’s thesis, University of Florida, Gainseville, FL.Google Scholar
- Siex, K. S. (2003). Effects of population compression on the demography, ecology, and behavior of the Zanzibar red colobus monkey (Procolobus kirkii). Ph.D. thesis, Duke University, Durham, NC.Google Scholar
- Struhsaker, T. T. (1975). The red colobus monkey. Chicago: University of Chicago Press.Google Scholar
- Struhsaker, T. T. (2000a). The effects of predation and habitat quality on the socioecology of African monkeys: Lessons from the islands of Bioko and Zanzibar. In P. F. Whitehead & C. J. Jolly (Eds.), Old world monkeys (pp. 393–430). Cambridge: Cambridge University Press.Google Scholar
- Struhsaker, T. T. (2000b). Variation in adult sex ratios of red colobus monkey social groups: Implications for interspecific comparisons. In P. M. Kappeler (Ed.), Primate males: Causes and consequences of variation in group composition (pp. 108–119). Cambridge: Cambridge University Press.Google Scholar
- Struhsaker, T. T., Marshall, A. R., Detwiler, K. M., Siex, K., Ehardt, C. L., Lisbjerg, D. D., et al. (2004). Demographic variation among the Udzungwa Red colobus (Procolobus gordonorum) in relation to gross ecological and sociological Parameters. International Journal of Primatology, 25, 615–658.CrossRefGoogle Scholar
- Williams, A. J., & Basha, A. U. (1996). A PRA carried out in Kiwengwa. Zanzibar: Conservation and Village Forestry Sections, Commission for Natural Resources, Zanzibar. Unpublished report.Google Scholar