Biodiversity and ecosystem services: Birds, bats, bees, and cocoa trees

Human populations are increasing rapidly and consumption is intensifying. Land is being cleared at a dramatic rate and biodiversity, which provides critical ecosystem services, is being lost at an unprecedented rate. Realisation of this crisis has created an urgent need to balance agricultural production with biodiversity. These two objectives are not disjoint, and indeed, biodiversity can play an integral role in increasing agricultural yields—sustainably. To achieve balance, we must manage ecosystems for species that provide support for crops (“ecosystem service species”, e.g. species that provide pest control) as well as those that encourage biodiversity (“keystone species”), and especially those that provide both functions (“cross-over species”).

To truly work towards this balance, we must first understand the food web, because species vary greatly in their value for agriculture and biodiversity services. For example, In North America, oaks support more than ten-fold higher richness of butterfly and moth species than most other tree genera. Bird and bat consumption of insects in Indonesian cacao plantations increased crop yield by 31%. The landscape context of agricultural plots was important and affected bird community dynamics and ecosystem services through spill-over of individuals from primary forest. This project will use state-of-the-art genetics methods to deduce the diet of animals from their faeces to address:

1) Which member species are most influential in encouraging crop yields and/or increasing biodiversity?
2) Do the above insights change depending on the context of the landscape, e.g. at sites near or far from forest?
3) How can we use the above insights to manage ecosystems that are both diverse and high-yielding?

The student will investigate these questions in the food web of plants, birds, bats and arthropods in African cacao plantations, the main ingredient of chocolate. Cacao is grown under a shade tree community, which can produce high biodiversity whilst maintaining ecosystem services, such as biocontrol of cocoa pest species. The student will conduct metabarcoding of bird and bat faeces (i.e. simultaneous sequencing of all diet items using advanced DNA sequencing technology). These sequences will then be compared to a local reference sequence database created by applying traditional sequencing methods to arthropods and plants. The student will then use sophisticated bioinformatics and statistical techniques, in collaboration with our colleagues at Glasgow University, to map the food web, examine species interactions, and link these to data on pest abundance and crop damage.
Through this project the student will develop many transferrable skills. General lab and specialised advanced DNA sequencing skills are applicable to jobs in many fields, including environmental testing, molecular biology, agricultural biotechnology, and medical testing/research. Numeracy, a widely desired trait, will be well developed through implementation of statistics and sophisticated bioinformatics. International collaboration will help expand the student’s network of contacts and along with scientific writing will aid in development of key communication skills. Beyond this, the methods developed to rapidly assess food web dynamics can be applied to a wide range of ecological problems and therefore this project will produce advances of both theoretical and practical importance.