Overview

Project Highlights:

  • Multidisciplinary: using a range of approaches to advance understanding of biodiversity and resilience in coastal systems.
  • Applied: answering research questions that will inform conservation management of priority habitats.
  • Legacy: building on experiments started over 40 years ago and initiating new experiments.

 

Sand dune wetlands or slacks are biodiverse habitats supporting many rare UK plant, invertebrate and vertebrate species. They are a priority habitat for nature conservation in Europe. Grazing and disturbance are important in coastal habitats for maintaining this conservation value because they prevent succession towards scrub habitat, so appreciating their wider impacts is essential for directing management activities. We have good understanding of how these factors can alter aboveground communities but our knowledge on belowground biodiversity in these systems is limited, particularly in the context of interactions between plants and soil components and consequences for biogeochemical functioning.

Earlier work characterised the accumulation of soil organic matter with slack age and documented changes in other soil properties (e.g. Jones et al. 2008). Few studies, however, have evaluated how soil microbial communities (Wasserstrom et al. 2017) and fauna (Butt & Chamberlain 2007) may develop, and whether altered belowground biodiversity and plant-soil interactions may drive changes in functional soil processes. Furthermore, there is pressing need to better understand how these changes may interact with different grazing or disturbance regimes. Using an established long-term experiment and wider network of study sites, this research will test links between organic matter quality, soil biodiversity and functional resilience in coastal systems, and provide unique belowground evidence to help optimise conservation management strategies.

In summary, the aim of this PhD is to answer the following questions:

  1. What are the long-term impacts of grazing regime on organic matter quality, microbial and faunal composition in coastal dune slack soils?
  2. Does the composition of soil biodiversity determine the capacity for biogeochemical functioning and its’ resilience to climatic and hydrological fluctuations?
  3. Can management strategies be identified which optimise for plant communities, soil biodiversity and functional resilience?

The project will focus on extensive dune slack systems at Ainsdale Sand Dunes National Nature Reserve, on the east coast of Lancashire. This location contains the Ainsdale Dune Slacks Long Term Experiment (LTE). This grazing experiment was established in 1974 and is the longest running dune slack wetland grazing experiment in the UK, consisting of sheep and rabbit exclosures. The proposal will build on earlier research at Ainsdale by Dr Millett (Millett & Edmondson 2013, 2015).

Nested grazing exclosures in a dune slack. These are part of the Ainsdale Dune Slacks Long Term Experiment.

Methodology

The student will (i) undertake in-situ biogeochemical measurements (N resins, GHG fluxes) and soil sampling for subsequent laboratory analyses (organic matter characterisation, soil biodiversity analyses) in the long-term grazing experimental plots and across a wider set of historical plots across slack locations at Ainsdale NNR (100 plots were sampled in 1985), (ii) conduct cross-site comparisons with other dune slack grazing exclosures at Sandscale Hawes National Nature Reserve in Cumbria and Braunton Burrows National Nature Reserve in Devon, using simple assays of ecosystem function (e.g. Tea Bag Index), (iii) select key locations to sample for laboratory resilience assays and carry out soil transplant experiments to test links between biodiversity and functional resilience, and (iv) carry out statistical modelling to identify appropriate management strategies that optimise above and belowground biodiversity.

The student will also play a central role in the development of further research activities at Ainsdale NNR, contributing to expansion of the existing grazing experiment and through establishment of new plots which will be part of an international multi-site experiment investigating grassland plant community assembly after disturbance – DRAGNet (Disturbances and Resources Across Global Grasslands; http://www.nutnet.org/dragnet). This will expose the student to a wider research network and provide opportunity for collaborative analyses.

Training and Skills

The student will receive in-house training at CEH Lancaster in plant-soil biogeochemical analyses (e.g. N Ionic exchange resin, organic matter characterisation, Greenhouse Gas flux measurement), measures of soil microbial activity (e.g. extracellular enzyme activity) and soil mesofauna identification. The student will apply to fund and undertake microbial analyses through the NERC NBAF facility at University of Sheffield. Training will also include training in plant identification and statistical modelling. This experience and training will develop some key skills identified by NERC as ‘most wanted’ for jobs in the environment sector such as multi-disciplinarity, translating research into practice, fieldwork and numeracy.

Timeline

Year 1: The student will undertake a literature review and archival work to determine the locations of historical plots and existing datasets. Plant ID, in-situ biogeochemical measurements and soil sampling at core plots and from a selection of the 100 historical plots at Ainsdale NNR. Biodiversity and functional metrics obtained in the laboratory.

Year 2: Identification of key sites at Ainsdale, Sandscale Hawes and Braunton Burrows for cross-site experimental work. Cross-site study will be initiated with plot characterisation and set up of experiment. Collection of samples for laboratory resilience assays and set-up of reciprocal transplant study at Ainsdale. Presentation of preliminary results at UK conference.

Year 3: Final data collected from cross-site and transplant experiments. Statistical modelling work to optimise management strategies. Data synthesis and write-up. Presentation of results at an international conference.

Partners and collaboration (including CASE)

The PhD will be based at the Centre for Ecology and Hydrology in Lancaster, and registered at Loughborough University. The primary supervision team will be Dr Aidan Keith at CEH, who has expertise in soil biology, and Dr Jon Millett at Loughborough University, who has expertise in plant community responses to grazing and is the principle investigator for the Ainsdale Dunes Slacks LTE.

Project partners are Natural England, who host the Ainsdale Dune Slacks LTE and have a primary interest in managing dune wetland nature reserves in England. The student will undertake a short placement with Natural England. The student will also collaborate with the Ainsdale NNR management team.

Ainsdale Dunes Slacks Long Term Experiment is part of the Ecological Continuity Trust (ECT) strategic network of long-term experiments. The student will benefit from being part of the small group of researchers working on this research platform and the wider ECT user group.

Further Details

Further details can be obtained from Dr Aidan Keith (ake@ceh.ac.uk). Applications should be submitted to Loughborough University, including a completed copy of the CENTA application form.