2014 26: Statistical modelling of how soil biodiversity and ecosystem function respond to human impacts in UK ecosystems

Co-Supervisors:
Paul Eggleton (Natural History Museum, Life Sciences)
Tom Bell (Imperial, Life Sciences)

The Natural Environmental Research Council (NERC) is supporting 15 PhD studentships within a new Doctoral Training Partnership (DTP) focused on Science and Solutions for a Changing Planet. This brings together Imperial College London’s world leading expertise with that of our partners to offer a unique world-class multidisciplinary PhD training programme. The DTP will provide students with in-depth, advanced research training, as well as training in professional and transferable skills. Partners will offer training and secondment opportunities designed to enhance the students’ employability. Those partners with business and government experience will also provide skills coaching in policy, regulation, and entrepreneurship.

Land use change is the biggest driver of biodiversity loss worldwide, and can undermine provision of vital but non-monetized ecosystem services. Studies of land use change effects on the biota nearly all consider only above-ground biodiversity, and most focus on taxa not strongly linked to key ecosystem services. Not enough is known about impacts on the biotas of soil and leaf litter, despite their importance in developing soil structure and composition, nutrient cycling and water drainage.

This project therefore aims to develop an integrative understanding, combining new data collection, Citizen Science approaches, analysis of existing data already in hand from monitoring and survey projects around the UK, and compilation of already-published data from similar biomes worldwide. It will develop data-rich and policy-relevant models of how soil and litter community composition and rates of ecosystem processes will respond to predicted future changes in land use in the UK. Questions include: (1) Are biotic responses consistent among major taxa, guilds and habitats, and can any differences be explained? (2) Do spatial comparisons and time series data give the same results? How important is biodiversity per se – rather than land use and management – in shaping ecosystem function?

Analysis of existing data: The student will collate data from papers that investigated how soil and litter invertebrate and soil microbial composition and ecosystem function respond to land use change, focusing on ecosystems found in the UK. These data will be supplemented with unpublished data sets: the largest two of which are from a detailed survey of all habitat types in the New Forest using many different sampling techniques, and from a structured repeated survey of soil and litter macrofauna from all UK woodland types. These data will be analysed to model and map soil and litter diversity, to model how these respond to land use change and management, and to make projections using land use scenarios such as those in the UK National Ecosystem Assessment.

Citizen Science: Earthworms play a major role in determining rates of water drainage and hence risks of prolonged waterlogging, but there is a dearth of basic information about their distribution and community composition within the UK. Although species-level identification requires expertise, assignment of individuals to key functional groups based on morphology is relatively easy. The student will therefore seek to develop a Citizen Science project, surveying earthworm assemblages in order to model their response to land use gradients. This project will be developed with the NHM’s Angela Marmont Centre and the Earthworm Society of Britain (ESB).

New sampling of microbial diversity: Although some major drivers of soil microbial diversity, notably soil pH, have been well-documented, linkages between microbes and the rest of the soil food web are poorly understood; also, little is known of how microbes and invertebrates interact to shape ecosystem function. The student will sample soil along environmental gradients known to impact macrofauna, in both acid and alkaline soils (N~100 communities), and analyse how assemblage composition (from next-generation sequencing) relates to a range of soil functional properties.