Effective solutions for howler conservation

Published source details Horwich R.H. (1998) Effective solutions for howler conservation. International Journal of Primatology, 19, 579-598.
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Summary

Study 1

As howler monkeys, Alouatta spp., can live in relatively small areas of forest of a range of ages, reintroduction may be possible once an area has been made safe e.g. from hunting and major forest cutting. Despite this, few reintroductions/translocations have been undertaken, except as fairly last resort rescue measures. A successful translocation of black howlers A.caraya in Belize, carried out from 1992 to 1994 in order to re-establish a viable population, is described here.

Complete troops of black howler monkeys were moved from the Community Baboon Sanctuary to the Cockscomb Basin Wildlife Sanctuary, where they had been eradicated by hunting.

After resolving the problem of hunting, 14 troops consisting of 62 individuals was moved during May of 1992, 1993 and 1994. In most cases these troops were held in pre-release field cages for 2-3 days to assist in acclimatization to their release area, and to observe the animals for any potential difficulties arising from the capture procedure. The translocation was done with extensive prior planning. This included: experience gained from earlier howler captures to establish best capture methods; a feasibility study; doner and release area surveys; evaluation and mapping of the release site; constructing suitable pre-release cages; and telemetry research.

Upon release in the Cockscomb Basin Wildlife Sanctuary, over 90% of the translocated howlers survived for 6 months and many for much longer. The population exhibited a normal (high) birth rate for the species; at least 38 young were born by 1997, and these offspring had an exceptionally high rate of survival. The population was estimated to be more than 100 individuals by early 1997. The extensive prior planning before the translocation was undertaken and careful procedures followed thereafter, are considered to have greatly accounted for the high survival rates and overall success of the reintroduction.

Study 2

In Mexico, the ejido system of communal land tenure has contributed to extensive deforestation leading to the loss of primate populations and other wildlife. Ejidos are peasant communities given use of land by the government. It covers millions of hectares and has led to major forest loss through slash-and-burn agriculture. Concurrently the state of Quintana Roo began the forest management program within the ejido system under the auspices of Sociedad de Productores Forestales Ejidales de Quintana Roo. Here, a village-sustainable logging system initiated at Petacab village, Quintana Roo, which has reduced levels of deforestation whilst benefiting villagers and wildlife, is summarised.

Study area and logging system: The author observed one of the village-sustainable logging projects in 1995, located at Petacab village. About half of the 54,000 ha area was utilized for logging and chicle production. The forest is divided into sections harvested under 25-year logging regimes. Before 1983, timber was extracted by the government. The community-based system was then initiated under a program which transferred forest management to a villager-managed cooperative. It allows the villagers to sell harvested timber, with profits distributed equally to around 200 ejido partners. The initial 3-year pilot plan was organized by government technicians, who convinced the villagers of the conservational value of the program and its economic value for them. Technicians also conduct forest surveys and give advice.

The forests are managed for the two species of trees used in the chicle industry (Brosimum alicastrum and Manilkara zapota) and others used for timber products. Mahogany Swietenia macrophylla and cedar Cedrela mexicana are grown in small clearings. Approximately 20,000 ha are used for agriculture and there is a small area (300 ha) of protected forest.

Monitoring: Within permanent plots, studies and monitoring has been undertaken on a long-term basis, concentrating on species of commercial value; however an aim is to maintain species diversity as a whole.

The Petacab project has proven successful in balancing sustainable forest use and forest conservation, which is benefiting for black howlers, spider monkeys Ateles geoffroyi and other wildlife.

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