Introduction - Conservation and Sustainable Use - page 3

(1995) give many examples of cases in which conservationists are quick to diagnose
a threat, only to find that their interventions are unsuccessful because the obvious
threat was not the true cause of a population's decline. For example, the decline
of the large blue butterfly in the UK was at first attributed to collecting, then to
habitat changes. It was only when its parasitism of a particular species of ant was
discovered that the true cause of the decline was known and appropriate action
could be taken (Elmes and Thomas 1992; Caughley and Gunn 1995).
The 'Bushmeat Crisis' is a major conservation issue (BCTF n.d.). There is much
concern that hunting wildlife for food, particularly in the forests of West/Central
Africa, is causing whole faunas to be wiped out, leaving empty forests behind them.
On the broad scale, it is undoubtedly true that hunting is unsustainable over much
of West and Central Africa (Fa et al . 2003). But when deciding on conservation
priorities at the local scale this may not be true. When people have been eating their
local wildlife for centuries, it may be that their use has reached sustainable levels.
This is likely to be the case for Takoradi market, Ghana (Cowlishaw et al . 2005a).
Bushmeat also illustrates the need to disentangle animal welfare concerns and cul-
tural differences in attitudes to wildlife from the issue of whether hunting is actu-
ally a threat to population survival in a particular location.
The first two steps in conserving an exploited species are to decide first whether
and why the species is of conservation concern; and second whether an interven-
tion that aims to reduce hunting of that species actually is the best approach to
addressing this concern. The most widely accepted method to judge whether a
species is of conservation concern is its IUCN—World Conservation Union red
list status (IUCN-SSC 2006). The IUCN red lists categorise species according to
their risk of extinction, based on criteria such as the rate of population decline,
small population size, limited range area and fragmentation. The most usual (but
not the only) reason why exploited species are placed on the IUCN red list is rapid
population decline. However, there are other valid reasons why a conservationist
may be concerned about the impact of exploitation on a species. These include its
cultural or economic significance, its importance as a component of the ecosystem,
or its vulnerability to future over-exploitation. In these cases, the population may
not currently be declining but an intervention is still appropriate.
Once we know why we are concerned about the species, we then need to assess
the relative importance of exploitation compared to the plethora of other poten-
tial threats (such as habitat loss, hybridisation, alien invasives, disease). Rarely
does a single factor act alone to cause extinction. Even if hunting is the main cause
of decline, other factors are likely to come into play as the population becomes
more threatened. Which factor should be tackled first is a product of the urgency
of the problem, its seriousness and the cost-effectiveness of measures that could be
taken. For example, Damania et al . (2003) used a model to suggest that the main
threat to tiger populations in Indian Protected Areas is not direct killing of the
tigers for sale, but depletion of their prey base for crop protection. Tigers have a
comparatively high population growth rate and can withstand a fairly high level
of hunting, so long as they have adequate prey to sustain the population.