Introduction
The specific objective of this project was to strengthen the generation
of appropriate, cost-effective and sustainable technologies for
rodent pest management in small-scale farming for the SADC region.
To do this, we carried out essential ecological research that
is required to develop sustainable community-managed rodent pest
control strategies. Many farmers will understand that rodents
are a problem and damage their crops, stored food and personal
possessions. However, awareness among farmers about the level
and scope of damage is often underestimated. For example, rodents
can transmit more than 60 different diseases, the symptoms of
many may be confused with other diseases (e.g. malaria, dengue)
where awareness is higher. It is, therefore, important to raise
awareness and generate accurate information about the multiple
damages caused by rodents, producing data that show true levels
of loss and contamination, and disease risks. Providing people
with the true cost of rodents on their livelihoods allows them
to consider how much they can invest (traps, poisons, labour)
in controlling rodents. The measurement of success also needs
to be reflected through the same rodent damages to livelihoods
(as opposed to simply counting the number of dead rodents). The
way people interact with rodents can be complex (seeing them as
food, pests, or even involved in witchcraft) so capturing people’s
knowledge, attitudes and practices with regards to rodents will
also be essential to improving the way in which rodent pests are
managed.
Rodent Ecology
The international scientific community and rodent pest control
industry increasingly recognise that rodenticide use, alone, is
not an appropriate solution for rodent pest problems found in
small-scale agricultural communities throughout Africa and Asia.
As has occurred with insect management, an integrated approach
for rodent pest management is increasingly viewed as more sustainable
and cost-beneficial. However, such an approach to rodent management
requires a good understanding about the rodent species, their
behaviours, breeding potential and habitat use in a given area.
Unfortunately, these factors are poorly understood for indigenous
African rodent species and habitats throughout Africa. Ecologically-based
rodent management can only be developed and applied through the
generation of rodent ecology research within relevant contexts.
Rodent Impact Management
Although effective rodent control methods exist, their poor application
and adaptation to particular situations often results in treatment
failures, leading to apathy and widespread acceptance of rodent
pests in the environment. Generally, there is a poor perception
about the impact of rodents on people’s livelihoods which
is partly due to their multiple impacts (agriculture and health),
the difficulty to assess some of the problems (e.g. crop loss)
and low public awareness (e.g. disease transmission) about the
damage caused by rodents.
Current rodent control practices are often based on the use of
rodenticides. Misuse of these poisons is unfortunately common
in many SADC countries, which poses a threat to human health and
environmental contamination by killing non-target species such
as predatory birds and using highly dangerous poisons which are
often banned. More importantly, misused rodenticides may not significantly
reduce the rodent population, therefore having little impact on
reducing the damage caused by rodents. When correctly used, rodenticides
can be a highly effective tool, but they are most appropriate
in large-scale, intensive, high-value situations where safety
and accuracy can be assured. The success of anticoagulant rodenticide
baits in controlling rodents in developed countries has inadvertently
stifled research on other aspects of rodent behaviour and ecology
that could help develop more sustainable methods of control in
the small-scale agricultural situations found in Africa. Because
rodenticides can be expensive and difficult to use safely, other
rodent management methods involving trapping and environmental
management are more appropriate for the rural agricultural situations
found in Africa. However, there has been insufficient research
to develop appropriate tools and strategies for rodent pest management
for different agro-ecological conditions, particularly targeting
small-scale farming.
Rodent-Human Interactions
Sylvatic rodents species do not generally come into contact with
people and are generally not considered to be pests. Many of these
species serve important ecological purposes (seed dispersal, predation)
and may act as reservoirs for various zoonotic diseases. Agricultural
expansion often disrupts and fragments wild habitats, causing
increased competition over resources and increasing interaction
with commensal rodents that migrate with expanding human-influenced
habitats. Sylvatic species may, therefore, pass disease to commensal
rodent species or come into increasing contact with humans by
foraging in and around human settlements. The impact of agricultural
expansion can have two major effects: 1) it puts people at greater
risk of contracting zoonoses such as bubonic plague 2) it can
drive sylvatic species locally extinct, replacing them with invasive
commensal rodents such as Rattus rattus, thereby reducing
biodiversity and ecological health. Evidence suggests endemic
diseases such as plague are spreading, and there is global concern
about new zoonoses emerging and expanding endemicity. However,
little research to understand these processes in Africa has been
carried out, particularly with regard to the role of agriculture
in facilitating zoonosis.