Long-term temporal dynamics of a migrant bird assemblage

Highlights:
This fully-funded PhD project provides an exciting opportunity for a highly-motivated student to utilise an outstanding 60-year dataset to quantify how compositions of migrant bird assemblages have changed over time, thereby addressing questions at the forefront of biodiversity research.

The student will be embedded within leading ecological research groups at Universities of Aberdeen and St Andrews, with research visits to Fair Isle and Norway, providing excellent scientific and wider skills training.

Overview:
Critical objectives in contemporary ecology are to understand how species and populations respond to environmental changes resulting from climate change. There is increasing evidence that many species can alter the timing of key life-history events, including seasonal migration. Yet, other species appear less able to track environmental change. Such divergent responses could mean that different species and populations whose migrations are currently synchronous become increasingly asynchronous (or vice-versa) as the climate and environment change. These changes will in turn alter the composition of species assemblages that co-exist at any point in time, potentially altering competitive or synergistic interactions and ultimate biological outcomes.

However, in general, the goals of understanding how species’ temporal ecologies and resulting assemblages can change over time have been hampered by a lack of high-quality long-term datasets that quantify timings of key life-history events within and across multiple species and years. Many datasets focus on one or a few species, precluding analysis of changing assemblage composition and synchrony. Analyses of available multi-year multi-species datasets have revealed that some communities have undergone substantial changes across years, but the consequences of these changes for species coexistence remain poorly understood. There consequently remains a need to fully assess the form of changing assemblage composition within and across years.

A migrant bird dataset collected on Fair Isle, Shetland, provides an exciting opportunity to undertake novel analyses of temporal changes in seasonal migration dates, and resulting dynamics of species assemblages across years. The dataset is remarkable in that, each day since 1955, expert observers have counted migrant birds on Fair Isle, following standardised protocols. Initial analyses revealed considerable among-species variation in migration timing across years in 13 long-distance migrant species (Miles et al. 2017). This implies that the temporal composition of the species assemblage must have changed over the years. However, such effects have not yet been directly quantified for this system, or any other. Furthermore, the temporal dynamics of other migrant species using Fair Isle have not yet been evaluated.

The PhD will address two primary questions that lie at the heart of understanding biological and biodiversity responses to climate and environmental change:

1) To what degrees have seasonal migration timings of different guilds of species (i.e. long-distance migrant passerines, short-distance migrant passerines and non-passerines) changed in similar or divergent ways across the observed 60-year timeframe?

2) To what degree have divergent changes in within-year migration timing among species caused changes in the composition of overlapping migrant bird assemblages across years, either within guilds or across all focal species?

To answer these questions, the student will utilise state-of-the-art methods in community ecology and statistical analyses of timeseries data, in which full training will be provided. The student will be embedded in dynamic and supportive research environments in Aberdeen & St Andrews, with additional opportunities to work with major research groups at NTNU, Norway, and to gain experience of fieldwork and public engagement with science through visits to Fair Isle. Overall, the project would suit a highly-motivated and collaborative student with interests in using long-term field datasets to address major questions in ecology.



Funded by NERC Studentships awarded to the SUPER Doctoral Training Partnership. The SUPER DTP partner Universities are St Andrews University, Aberdeen University, Edinburgh Napier University, Heriot-Watt University, the University of the Highlands and Islands, Stirling University, University of Strathclyde and the University of the West of Scotland. Underpinning these research partners, providing additional training and projects are Marine Scotland, Scottish Natural Heritage, and the James Hutton Institute, among a total of 40 stakeholder organisations including industry and government agencies and international collaborators.