Environmental Engineering Reference
In-Depth Information
Finally, there is a need to ascertain whether the reduction in poaching is actually
leading to our desired conservation outcome—a stable or increasing population of
the species of concern. If poaching is not the main cause of population decline,
then effort invested in stamping it out will not be effective.
In Chapter 2, we discussed methods for measuring population abundance, and how
to determine the power monitoring programmes have to detect trends, based on
the levels of sampling error obtained. In this section, we look at
cost-effectiveness
in monitoring, how to handle trade-offs between the cost of monitoring and its power
to detect trends, and how to ensure that monitoring is sustainable in the long-term.
Long-term sustainability in the context of small-scale community-based conservation
implies that the techniques are simple, low tech, robust and easily analysable.
7.4.2.1 Participatory monitoring
The idea of participatory monitoring is that it should be bottom-up; carried out by
local people, and collecting data of relevance to their management priorities (Halls
et al
. 2005). This should ensure that the monitoring is supported by local people,
leads more readily to management action, and is substantially more cost-effective
than monitoring carried out by or for outsiders. Participatory monitoring is
immensely fashionable (see web resources in Section 7.8 for a few links), although
in most cases it is used to monitor the success of interventions, rather than ecological
trends. Some case studies do exist for its use to monitor ecological trends
(Danielsen
et al
. 2005). The general message from these studies is that the
approach is too new for a full assessment of its effectiveness, and that there are
potential issues with the quality and bias of the data, meaning that inferences about
ecological trends cannot always be made with confidence. However, there can be
major benefits in terms of engaging and empowering local people. Innovative ideas
have been generated to engage local people in monitoring (Box 7.3).
7.4.2.2 Using information from harvesting
Often we think of monitoring as a separate and independent activity from har-
vesting. However, harvesters traditionally use the information that they gain while
harvesting as an indicator of population health. Catch per unit effort (CPUE) is a
widely used indicator of population trends, the assumption being that as popula-
tion sizes decline, individuals are harder to catch. There are a whole set of pitfalls
which undermine the validity of this assumption (Chapters 2 and 4). Nonetheless,
it is seductive to think that information collected while harvesting can help to
inform management, and the potential benefits are large enough for the idea to be
worth investigating. Using CPUE as an indicator of abundance forms a corner-
stone of commercial fisheries management, because of the logistical difficulties of
making an independent population estimate (Hilborn and Walters 1992).
However, the information that harvesters use to assess the health of their resource
