Grassland parasites and community dynamics under climate warming

This project will be supervised by Professor Eric Morgan of Queen’s University School of Biological Sciences, Dr Lesley Lancaster of University of Aberdeen School of Biological Sciences, and Dr Thomas Fleming of the Agri-Food and Biosciences Institute. The start date will be 1 October 2019.

Global warming is already affecting the distribution and phenology of a wide range of organisms, including parasites of plants and animals [1,2]. Most studies of the biological effects of climate change, however, consider physiological processes and single species responses, despite the fact that inter-species interactions are known to strongly influence outcomes of climate change at community level [3]. This limitation could undermine predictions of future impacts of parasites on natural and agricultural ecosystems.

This project will investigate how responses to warming differ among linked species in grassland-soil communities in the UK, including nematode parasites, and attempt to predict effects of climate change on ecosystem functioning and primary productivity, in both natural and managed systems.

The general approach will be to: (i) calibrate thermal response curves for key species in each functional group (including plant-parasitic and animal-parasitic nematodes, grass, and grazers); (ii) compare curves and identify ‘winners and losers’ under elevated temperature scenarios; and (iii) run dynamic models to compare outcomes under seasonally varying climates and climate change. Existing data on the climate-dependence of these groups will underpin model calibration and validation, complemented by additional experiments as needed. Following calibration, models will be tested in controlled-temperature mesocosms, and validated against longitudinal data on species responses under baseline and warmed (open-top chamber) field conditions.

Project results will enhance understanding of how the effects of different thermal responses among species in ecological communities are modified by the linkages between them to determine net impacts on ecosystem function. Outputs will illustrate how non-linear responses to climate change might affect natural and managed grassland systems. For example, accumulated impacts of plant-parasitic nematodes through the growing season might curtail autumn grass growth, while advancing spring temperatures increase earlier grass availability; but grazer responses that increase spring grazing might increase contact with overwintering animal parasitic nematodes. Model sensitivity analysis will map key species responses and vulnerabilities within the system, and support rational prioritisation of areas for future research. Scenario analysis will explore likely responses in terms of the stability and productivity of natural grassland systems, and rational adaptive management on livestock farms. Consequences of parasite adaptation to warming could also be explored through the model, and response curves compared among populations from different climatic zones.

The successful student will work with leading research groups in Belfast and Aberdeen, and benefit from state-of-the-art facilities, including climate-controlled experimental chambers in the new Biological Sciences building at QUB, and ISO17025 accredited nematology laboratory at AFBI. Training will be provided in experimental design and analysis, mathematical and computational modelling of population and community dynamics, and a wide range of laboratory and field methods in parasitology and ecology. The student will be expected to contribute fully to development of the project aims and planning following initial guided work, and will be supported to build experience in stakeholder engagement and public communication of science.

[1] Bebber DP, Ramotowski MAT, Gurr SJ (2013) Crop pests and pathogens move polewards in a warming world. Nature Climate Change 3.11: 985

[2] Rose H, Caminade C, Bolajoko MB, Phelan P, van Dijk J, Baylis M, Williams D, Morgan ER (2016) Climate-driven changes to the spatio-temporal distribution of the parasitic nematode, Haemonchus contortus, in sheep in Europe. Global Change Biology 22, 1271-1285.

[3] Lancaster, LT., Morrison, G. & Fitt, RN. (2016). Life history trade-offs, the intensity of competition, and coexistence in novel and evolving communities under climate change. Philosophical Transactions of the Royal Society B: Biological Sciences, vol. 372, no. 1712, 20160046.