Conserving biodiversity and enhancing food security: the role of birds and bats as suppressors of rice insect pests in West Africa
Task 1
For which species of insectivorous bats and birds do rice fields constitute suitable foraging habitat?
To ascertain their potential impact as pest suppression agents in rice fields, a key question is the extent to which bats and birds make regular use of rice fields as opposed to other habitats available in the wider landscape. We will employ a suite of complementary sampling methods (mist nets, harp traps, autonomous acoustic recorders) to comprehensively survey bats and birds across all major habitat types in the study area.
Task 2
Are insectivorous bats and birds effective at suppressing pest insect populations of rice?
Demonstration of consumption alone is not enough to prove that bats or birds are able to exert enough predation pressure to influence pest population dynamics. To evaluate this, we will link temporal patterns in predator abundance, with those of pest and non-pest prey availability and consumption (inferred through insect trapping and dietary analyses, respectively). This can give an indication of whether bats and birds actively track changes in pest populations
Task 3
What is the functional role of individual species of insectivore bats and birds in this predator-pest rice network?
Agroecosystems contain complex web of interacting organisms that require a greater understanding to inform biological control strategies for sustainable pest management. We will merge data from Tasks 1 and 2 to produce a temporal multilayer network of predator-pest interactions to understand their dynamics through season and timing of crop-management activities (e.g. crop flooding).
Task 4
What is the impact of insectivorous bats and birds on rice pests?
One of the measures for the ecosystem service of pest suppression is the reduction of crop damage and yield loss. We will use exclosure experiments in rice fields to disentangle the relative importance of bird- vs. bat-mediated pest suppression and to quantify the effects of vertebrate predation in terms of herbivorous arthropod abundance, plant damage, and crop yields.
Task 5
What is the economic value of bat- and bird-mediated suppression rice pests?
Estimating the economic importance of vertebrate predators in agricultural systems is challenging, but urgently needed in view of the enormous value of such information for conservation as well as economic and food security in developing countries. We will estimate the monetary value of bat- and bird-mediated pest suppression based on all relevant parameters of the predator-pest-crop system, and extrapolate our local-scale estimates to the country, regional and continental scale.
Task 6
Can artificial roost provision increase the benefits of bat-mediated pest suppression?
Although it has been shown that artificial roosts may attract bats to agricultural areas, to date there is mostly only anecdotal evidence for this to increase foraging activity over those areas. If bat houses placed in agricultural areas were readily adopted by bats, this would be a much more effective and, if done in lieu of pesticide use, less environmentally detrimental means of reducing pest-related damage of one of the most globally important food crops. The installation of bat houses will also provide an excellent opportunity to involve the local population in this project and to understand and discuss their perceptions and attitudes towards bats and eco-agriculture.