FACTORS AFFECTING ECOSYSTEM SERVICE PROVISION FROM DUNG-ASSOCIATED INVERTEBRATES
Project Leader: Dr Sarah Beynon
Supervisor: Dr Owen T Lewis
Students: Michaela Peck & Sabrina Hearn
Funding: University of Oxford Professor Sir Richard Southwood Scholarship & NERC research grant
Anthropogenic (human-led) environmental perturbations have the potential to cause extinctions which can alter the structure and functioning of ecological communities. Dung-associated invertebrates, in particular dung beetles (Coleoptera: Scarabaeidae), provide valuable ecosystem services in agro-ecosystems by increasing rates of dung decomposition.
Perturbations of the dung-associated invertebrate community may include the intensification of grazing pastures and the treatment of livestock with parasite control products (anthelmintics and ectopartasiticides) (Beynon, 2012a,b; Wall & Beynon, 2012). Using a combination of field and manipulative mesocosm experiments, we quantified impacts of perturbations on dung attractiveness, dung-associated insect emergence and the function of dung removal.
Dung beetle species varied in sensitivity to the parasiticide, ivermectin. Impacts of ivermectin on functioning were also species-specific. Using these species-specific sensitivity data, dung beetle communities were manipulated to assess the functional impacts of realistic extinction scenarios. Mesocosm manipulation experiments suggested that losing those species most sensitive to ivermectin severely retarded short and long term functioning. In the short term, species-rich assemblages sustained functioning in the context of perturbation with ivermectin, but functioning of species-rich assemblages did not differ from that of species-poor assemblages in un-perturbed conditions (Beynon et al., 2012a). This suggests that apparent functional redundancy of species in agro-ecosystems should be interpreted cautiously in the context of perturbation. However, in the long term, there was a significant, positive effect of species richness on dung removal irrespective of perturbation.
We provide the first evidence that alternative products for parasite control, in this case ‘Bug A Tub’ (a free-choice mineral lick containing <5 % diatomaceous earth and undisclosed plant oils) and potentially a copper bolus, can affect insects colonising dung, highlighting a need for tests on the environmental safety of alternative products (Beynon et al., 2012b). The potential lack of density compensation (which was assumed in all manipulation experiments) and potential multiplicative impacts of numerous perturbations common in agricultural systems, suggest that functional impacts may be even greater than predicted here.
The project is run by Dr Sarah Beynon and leads on from her doctorate at the University of Oxford. She was awarded the Royal Entomological Society's Wallace Award for the best entomological thesis written in the English language leading to a PhD and delivered a Plenary Lecture at the Royal Entomological Society's European Congress in 2014. She will also deliver a Plenary Lecture on this work at the Royal Entomological Society's International Symposium in 2015. This research also led her to be nominated for the Royal Agricultural Society and Oxford Farming Conference ‘Practice with Science’ award and the Royal Welsh Agricultural Society Oxford Farming Conference bursary. She contributed to the Eurobats Report of the Intersessional Working Group on Impact on Bat Populations of the Use of Antiparasitic Drugs for Livestock and is working alongside Glastir at producing a best practice for livestock parasite control and impacts on dung beetles. She was chosen to attend a British Council-funded UK-Brazil workshop on future collaborations for research on sustainable agriculture (Sáo Paulo). She was also invited to attend the Rio+20 Earth Debates closing debate in London to provide input on the topic.
Beynon, S.A., Slade, E.M., Mann, D.J. & Lewis, O.T. (2012a) Species-rich dung beetle communities buffer ecosystem services in perturbed agro-ecosystems. Journal of Applied Ecology, 49, 1365-1372.
Beynon, S.A., Peck, M., Mann, D.J. & Lewis, O.T. (2012b) Consequences of alternative and conventional endoparasite control in cattle for dung-associated invertebrates and ecosystem functioning. Agriculture, Ecosystems & Environment, 162, 36-44.
Beynon, S.A. (2012a) Potential environmental consequences of administration of anthelmintics to sheep, Veterinary Parasitology,189, 125-135.
Beynon, S.A. (2012b) Potential environmental consequences of administration of ectoparasiticides to sheep, Veterinary Parasitology, 189, 113-124.
Wall, R. & Beynon, S. (2012) Area-wide impact of macrocyclic lactone parasiticides in cattle dung. Medical and Veterinary Entomology, 26, 1-8.
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