The impact of megafaunal loss and climate change on ecosystem functions in aridland ephemeral river systems
Dr G Cowlishaw
Dr N Pettorelli
Prof E Black
No more applications being accepted
Competition Funded PhD Project (European/UK Students Only)
Understanding the role megafauna play in shaping ecosystem functions is critical to protecting ecosystem services in many parts of the world. It is also of fundamental importance to the global rewilding agenda. However, our ability to predict the impacts of megafaunal loss on the long-term trajectory of ecosystems, especially in the wider context of climate change, is surprisingly limited.
This project explores the impacts of megafaunal loss and climate change on key ecosystem functions in the ephemeral river systems of Namibia. These rivers run from central Namibia westwards to the coast, through the Namib Desert. Although they only flow for a few weeks each year following seasonal rains, the groundwater supports rich riparian vegetation, with the rivers acting as linear oases providing vital resources to both wildlife and people all year round.
There are 12 ephemeral rivers that cross the Namib Desert. Historically, all would have been home to a variety of megafauna, including desert elephants, giraffe, and lions. Over the last 150 years these megafauna have been hunted out of most of the rivers, but still persist in the more remote riverbeds. These 12 riverbeds therefore provide a unique natural experiment in which the impacts of megafaunal loss can be assessed through a comparison of the ‘removal’ replicates and the ‘persistance’ controls. The impacts of additional threats, including invasive species (mesquite) and damming, which occur in various combinations with megafaunal loss, can also be assessed.
The first step of the project will investigate the sensitivity of these riparian ecosystems to climate using satellite data. The student will adopt a variety of approaches, including an assessment of variation in riparian plant productivity across seasons and years with rainfall and temperature, utilising newly available long term datasets. The student will then investigate how these patterns vary between catchments, according to the presence/absence of megafauna and other threats. Special attention will be paid to tributaries, which recent research (by two of the supervisors) suggests may play an unusually important role in ephemeral rivers. Over the course of the project, we will also explore the possibility for the student to collect new field data on the ecological roles of elephants and giraffe in these ecosystems, focussing on tree pollination and seed dispersal. In the final stages of the project, the student will project future scenarios for these ecosystems on the basis of 21st Century climate projections for these regions and potential changes in megafaunal status (loss where currently present, restoration through rewilding where absent) and other threats, and further explore the efficacy of potential management options to mitigate these impacts. The climate change work will exploit bias corrected and high resolution climate model output, developed through the Future Climate for Africa programme and will build on recent research conducted by one of the supervisors (http://www.futureclimateafrica.org/).
Local conservation managers and policy makers in Namibia will be involved in the project from the outset, and the research findings disseminated in a format tailored to local needs, to ensure maximum impact locally. The findings will also be published in the international literature, providing a valuable case study with global reach.
The supervisory team for the project comprises Drs Guy Cowlishaw and Nathalie Pettorelli at the Institute of Zoology, and Professor Emily Black in the Department of Meteorology, University of Reading. This project is funded by the NERC Centre for Doctoral Training in Quantitative and Modelling Skills in Ecology and Evolution (the QMEE CDT).
To apply, please send your CV and cover letter to Guy Cowlishaw by 5pm on Weds 16 Jan 2019 ([Email Address Removed]). The cover letter should explain your interest in and suitability for the project and the QMEE CDT. It should also include the names and e-mail addresses of two academic referees, at least one of which should have supervised you on a previous research project. Informal enquiries are also welcome.
This project is funded by the NERC QMEE CDT (http://www.imperial.ac.uk/qmee-cdt/) and commences in Autumn 2019. Full studentships (fees and stipend) are available to UK and other EU nationals who have resided in the UK for three years prior to commencing the studentship.