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NERC DTP BC215: Understanding the impacts of insect decline on ecological function and human well-being

Supervisor: Dr Lynn Dicks

Project summary:

Insects constitute more than half of global biodiversity and play a central role in the functioning of terrestrial ecosystems. Declines of insect abundance, biomass, and range are being reported from many places around the world, from the Arctic to the tropics, across insect orders, and from a spectrum of ecological guilds (Montgomery et al. 2019; Wagner 2020), but they are not universal, with certain taxonomic groups, guilds or communities clearly not declining (Crossley et al. 2020). An important aspect of recent studies is the decline of formerly common species, not just rare taxa, with the realization that such losses likely come with changes to ecosystem function, stability and resilience. This project will work with existing long-term insect assemblage and time series datasets to develop and explore hypotheses about relationships between insect (or arthropod) abundance, diversity, and the stability of ecological functions. It will also develop methods to value ecosystem services provided by insects, at large or even global scales.

What the student will be doing:

The student will join a global community of evidence synthesis and insect conservation researchers, working to identify and analyse insect time series and assemblage datasets from all over the world (EntoGEM). The work will be mostly desk-based, identifying and analysing large datasets. Example hypotheses that could be tested with datasets already identified in EntoGEM include: 1) As insect communities become less diverse, they have lower invariability in abundance or biomass (the inverse of variability) over time or space, leading to lower stability of function. 2) Ecological theory predicts that invariability increases with area in a non-linear fashion (known as the Invariability Area Relationship IAR (Wang et al. 2017)). Homogenisation of insect communities at large scales might be expected to lower the slope of the IAR. The student will also develop methods to upscale the valuation of insect-derived ecosystem services. Following Losey & Vaughan (2006), this will probably focus on pollination, pest regulation, dung removal by Scarabidae and recreational values of certain groups of vertebrates that rely on insects for food (including hunting, fishing and birdwatching). It may be possible to develop new methods to value waste removal in cites, building on estimates of food removal (Youngsteadt et al. 2015), and human disease vector control, building on methods used for the value of controlling livestock pests. There will also be opportunities to undertake modelling of ecological networks, such as plant-pollinator networks, to determine how declines in insect species affect the delivery of key ecosystem functions. Other possible questions include, how do insect declines affect the abundance and stability of species populations and communities? These questions can be addressed using the latest topological or dynamic network models, incorporating key features such as extinction cascades and the ability for species to 'rewire' their connections.

References:

Crossley, M.S., Meier, A.R., Baldwin, E.M., Berry, L.L., Crenshaw, L.C., Hartman, G.L., Lagos-Kutz, D., Nichols, D.H., Patel, K., Varriano, S., Snyder, W.E. & Moran, M.D. (2020) No net insect abundance and diversity declines across US Long Term Ecological Research sites. Nature Ecology & Evolution.

Losey, J.E. & Vaughan, M. (2006) The Economic Value of Ecological Services Provided by Insects. BioScience, 56, 311-323.

Montgomery, G.A., Dunn, R.R., Fox, R., Jongejans, E., Leather, S.R., Saunders, M.E., Shortall, C.R., Tingley, M.W. & Wagner, D.L. (2019) Is the insect apocalypse upon us? How to find out. Biological Conservation, 108327.

Wagner, D.L. (2020) Insect Declines in the Anthropocene. Annual Review of Entomology, 65, 457-480.

Wang, S.P., Loreau, M., Arnoldi, J.F., Fang, J.Y., Abd Rahman, K., Tao, S.L. & de Mazancourt, C. (2017) An invariability-area relationship sheds new light on the spatial scaling of ecological stability. Nature Communications, 8.

Youngsteadt, E., Henderson, R.C., Savage, A.M., Ernst, A.F., Dunn, R.R. & Frank, S.D. (2015) Habitat and species identity, not diversity, predict the extent of refuse consumption by urban arthropods. Global Change Biology, 21, 1103-1115.

 

Specific qualifications desirable for this particular project:

  • A degree in biological or environmental sciences with a strong quantitative component, or mathematical biology
  • An interest in data analysis, entomology and insect conservation
  • An understanding of ecosystem services/nature’s contributions to people

Additional information:

Funding is available for this project via the NERC Cambridge Climate, Life and Earth (C-CLEAR) Doctoral Training Partnership – please refer to their website for more information: https://nercdtp.esc.cam.ac.uk/projects/BC215