Namibia Nature Foundation
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Research proposal: Conservation of Nile Crocodiles in north-eastern Namibia: ecology, socioeconomics and sustainable utilisation. By Patrick Aust


Abstract

The aim of this study is to get a better understanding of factors influencing Nile crocodile ecology, conservation and management outside of protected areas and to identify community-centric strategies that will ensure their long term viability within human dominated environments.

Introduction

Nile crocodiles are top predators and keystone species within their natural environment. As such they perform an integral role in maintaining the structure and function of freshwater ecosystems.

Historically they were heavily hunted for their valuable hides and numbers were severely reduced almost worldwide (e.g. Gans et al.1976). In recent years, through a combination of trade controls and innovative applied conservation measures, crocodiles are thriving and numbers are back to carrying capacity throughout much of their range (e.g. Brown et al. 2005)

Nile crocodiles do not co-exist easily with humans. With increasing competition for scarce resources, crocodile attacks on humans and livestock have become more common and they are increasingly regarded as serious problem animals (McGregor, 2005). Conversely, in some areas crocodiles have suffered from direct persecution and more recently from the overwhelming increase in human pressure and alteration of riverine habitats (Ligomeka, 2000).

The lucrative crocodile ranching and trophy hunting industries have been heralded as potential solutions to some aspects of crocodile human conflicts. Ranchers collect crocodile eggs from the wild and raise the animals to produce skins for the fashion industry whilst hunting operations facilitate high paying tourists in shooting trophy animals. Both these industries are dependent on healthy wild crocodile populations and the resulting benefits they have for both humans and crocodile conservation are substantial (e.g. Hutton, 1992; Revol, 1995).

This increased trade in crocodiles has been seen as a positive step towards sustainable development in Africa; however the value of crocodiles often remains largely unrealised by the communities co-existing with them. Profits from crocodile based industries do filter through but in most cases not enough to offset the costs of living alongside a top predator. Thus the human crocodile conflict persists largely unabated and is most likely to escalate as human pressure increases (McGregor, 2005).

Conservation strategies that reduce costs incurred by local people and promote the exploitation of large predators are needed to create financial incentives for conservation (Mills, 1991).

Much work has been carried out on the ecology and conservation of crocodiles in Southern African. Very few studies, however, have focused on the interaction of wild crocodile populations with local communities (Thorbjarnarson, 1999). This project aims to investigate various ecological, economic and social aspects of the human crocodile interface in an effort to determine whether crocodiles can become an economically viable umbrella species outside of protected areas.

The situation in Namibia

In Namibia wild crocodiles are only found in the three main riverine ecosystems in the North East of the country and these populations are essentially contiguous with larger populations from neighbouring countries (Branch, 1998).

During the 1960s and 1970s, the hunting of wild crocodiles for their skins throughout the region resulted in a drastic decline in numbers (Gans et al.1976). This prompted the relevant National Governments to curb crocodile hunting and in 1975 the then Namibian Department of Nature Conservation listed the Nile crocodile as a protected species. This, together with increasing international controls in the trade of crocodilian skins resulted in the gradual recovery of the wild population.

Today the provisional conservation status for this species in Namibia is "Peripheral" implying that the species is vulnerable only due to limited habitat (Griffin, 2003). A national status survey carried out in 2004 found crocodile numbers to be healthy. Furthermore, in the last five years at least 23 people and 158 livestock animals have been killed by crocodiles, suggesting that crocodiles could become a major problem (Brown, 2005). These findings have contributed to the January 2005 CITES downlisting of the wild Namibian Nile crocodile population from Appendix I to Appendix II (Brown, pers comm.)

To date, apart from the 2004 survey, the management and conservation of crocodiles in Namibia has essentially been limited to a single crocodile farm, the occasional control of problem animals and a limited amount of trophy hunting. No crocodile ranching operation exists (i.e. ongoing collection of individuals or eggs from the wild) and no formal crocodile research has been carried out.

Research Objectives

  1. To determine the distribution and status of Nile crocodiles on the Caprivi and Kavango systems
  2. To determine the impact of current harvesting regimes
  3. To determine the impact of various land tenure scenarios
  4. To investigate whether ranching and hunting alone can offset the economic and social costs associated with conserving Nile crocodiles outside of protected areas
  5. To determine the long term population viability under current management and conservation practices
  6. To investigate the optimum management strategies based on increased community involvement and distribution of benefits.

Methods


Objective 1

A variety of survey techniques will be employed to estimate population size, distribution and abundance:

  1. Aerial surveys: Considered the cheapest and quickest way of carrying out large scale crocodile surveys
  2. Daylight and spotlight surveys by boat: especially effective where aerial and nesting surveys are impractical
  3. Nesting surveys: Population size can be estimated by comparing the total number of nests with estimates of the proportion of sexually mature females nesting and the proportion of sexually mature females in the total population
  4. Mark recapture: Capturing and tagging crocodiles can provide information on movements, sex ratios and total population size.

Objective 2

To determine the impact of current harvesting regimes, questionnaires and semi structured interviews will be carried out with relevant sectors of the crocodile industry. Historical data will be collated from various sources. These data will be correlated with demographic and distribution data detailed in objective 1.

Objective 3

The impact of various land use scenarios will be determined by mapping the terrestrial and the aquatic landscape according to natural and human characteristics. Correlated with data obtained from objectives 1 and 2, these data will be used to quantify the effects of habitat alteration on crocodiles and determine habitat suitability criteria for the species.

Objective 4

Carry out a cost-benefit analysis by means of questionnaires, semi structured interviews and rapid rural appraisals to determine the following:

  1. The social and economic costs and benefits sustained by local communities as a result of crocodile activity (e.g. human injuries and fatalities, damage to fishing nets, livestock losses)
  2. The social and economic value of the crocodile trophy hunting and crocodile ranching/farming industries
  3. Determine how the answers to these questions will influence the decision making processes of those who are responsible for the ongoing conservation of the crocodile population.

Objective 5

Carry out a population modeling exercise to assess the vulnerability of the population. This will be done through a process of identifying threats and evaluating the consequences of different management and conservation strategies on the probable size of the population.

Objective 6

  1. Determine theoretical sustainable yields and compare these to current harvests
  2. Investigate the potential of additional stages within the crocodile's life cycle that may be exploited by local communities
  3. Identify utilisation systems that will involve an increase in local community involvement and benefit
  4. Identify regionally compatible monitoring systems on which to base future management decisions.

Additional project activities

  1. Education and awareness: Many crocodile related conflict issues arise from a lack of knowledge and understanding; often compounded by strong beliefs in witchcraft and the supernatural. If conflict issues are to be reduced it is imperative that local communities are educated in basic crocodile ecology and behaviour and the appropriate conflict avoidance measures. Furthermore, efforts are needed to raise awareness of the ecological and economic benefits associated with conserving crocodiles. The project will carry out various education and awareness activities within the study area during the duration of the fieldwork. This will involve giving talks and presentations to local schools and communities as well as safari lodges and foreign tourists
  2. Community development work: The project will assist with experimentation and implementation of low cost procedures and devices aimed at reducing crocodile conflict. This will involve activities such as the building of protected watering areas like wells or simple water lifting devices such as 'shadoofs'.
  3. Assistance in carrying out current management operations: the project will be available to assist in local crocodile management operations such as the location of nesting sites and removal of problem animals.

Principal Investigator

Patrick Aust is a 30 year old South African citizen. He has spent virtually his entire life living and working in rural Africa and has been interested in wildlife and African ecosystems conservation since early childhood. After leaving school he was awarded a BSc degree in Zoology and Geography through the University of South Africa (UNISA) and an Honours degree in Zoology through Potchefstroom University, South Africa. Both these qualifications were undertaken via correspondence whilst Patrick was working in Zimbabwe. He has spent the last five years working with large carnivores in both a pure research and an applied conservation capacity. Patrick was awarded a full Beit Scholarship in December 2004. He registered for a three year PhD through Imperial College, London in October 2005. This will be a three year project forming part requirement for the fulfillment of his PhD qualification.

Assistance required from Namibian Ministry of Environment and Tourism

The project requires the necessary government permission to do research on Nile crocodiles in North Eastern Namibia (including Zambezi, Kwando, Linyanti, Mashi, Okavango & Kunene river systems). This will mainly involve permission to carry out the necessary research in protected wildlife areas, including permission to capture and restrain Nile crocodiles.

References

Branch, W.R. (Ed.).1988. South African Red Data Book - Reptiles and Amphibians. Foundation for Research Development (CSIR), Pretoria, South Africa.

Brown, C.J., Stander, P., Meyer-Rust, R., Mayes, S. 2005. Results of a Crocodile Crocodylus niloticus survey in the river systems of north-east Namibia during August 2004. CoP13 Inf. 26 CITES Proceedings of the Thirteenth meeting of the Conference of the Parties in Bangkok, Thailand. [pdf 1,621kb]

McGregor, 2005. Crocodile crimes: people versus wildlife and the politics of postcolonial conservation on Lake Kariba, Zimbabwe GEOFORUM 36 (3): 353-369 MAY 2005

Gans, C. Pooley, A.C. 1976. Research on Crocodiles. Ecology 57 (5): 839-840 1976

Griffin, M. 2003. Annotated checklist and provisional national conservation status of Namibian reptiles. Namibia Wissenschaftliche Gesellschaft. Windhoek, Namibia.

Hutton, J. M. 1992. The CITES Nile Crocodile project. A publication of the Secretariat of the Convention on International Trade in Endangered Species of Wild Fauna and Flora, Lausanna, Switzerland.

Ligomeka, B. 2000. Malawi Plans Crocodile Management Programme. Environment News Service, November 2, 2000

Mills, M.G.L.1991. Conservation management of large carnivores in Africa. Koedoe 34, 81-90

Revol, B.1995. Crocodile Farming and Conservation, the example of Zimbabwe. Biodiversity Conservation 4 (3): 299-305 APR 1995

Thorbjarnarson, J.1999. Crocodile Tears and Skins: International Trade, Economic Constraints, and Limits to the Sustainable Use of Crocodilians. Conservation Biology, Pages 465-470 Volume 13 No. 3

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