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Climate-induced phenological change and its consequences for bird populations

Final Report Summary - BIRD POPULATIONS (Climate-induced phenological change and its consequences for bird populations)

There is clear evidence that migratory birds have over the last few decades advanced their phenology, i.e. timing of activities such as spring migration and breeding. There is a consensus that these changes have occurred as a response to climate change. Species unable to adjust their phenology have also shown worse declining populations, but the reasons for this correlative pattern are so far on a speculative level. Understanding the mechanisms underlying this trend is necessary for predicting long term population dynamical consequences of climate change and taking possible conservational action.

The project aimed at sorting out associations between phenology and population dynamics, and to bridge the gap between these two areas of research classically considered separately. Migratory birds provide an appropriate model system for this purpose due to their apparent phenological responsiveness, well known ecology and the large amounts of data available. More specifically, the research objectives were to: i) develop models for quantifying phenological variation, ii) link phenology and population models, and iii) investigate different scenarios of climate change by computer simulation. These aims were approached by analysing standardized data from Nordic bird observatories and long-term monitoring schemes, in collaboration with responsible institutions, using state-of-the-art statistical modelling. The purpose was to produce 5–6 manuscripts ready for submission to international scientific journals during the project.

The project implementation was significantly affected by the birth of the researcher’s first child and suspension due to paternal leave, as well as by termination of the project, due to the successful application of a 3–5 year senior researcher position in Finland. In total, the effective implementation of the project had a duration of 14 ½ moths, which is ca 60 % of the planned 24 months. The objective of the project was amended to do research corresponding to the workload of 3–4 complete manuscripts. Further, the specific objective iii) of doing computer simulations of different climate change scenarios was dropped.

The project was carried out in the period April 2012 to August 2013 at the University of Oslo in an internationally acknowledged research group: Centre for Ecological and Evolutionary Synthesis (CEES). The group is chaired by Prof. Nils Chr. Stenseth, who also was the scientist in charge for this project. The broad expertise of the CEES and its excellent track record ensured a stimulating environment for carrying out research and acquiring complementary skills necessary for career development.

At the termination of the project, the direct output of the fellowship was one published article, one submitted manuscript, and four ongoing manuscripts. The total workload of these corresponds to 4.1 manuscripts and is hence well in concordance with the modified aim. The researcher has an excellent opportunity to continue his ongoing work at his new position, implying that the manuscripts in progress are very valuable. In addition to these, the researcher published during the project three scientific manuscripts from his former project, three non-peer reviewed or popular science articles and gave two talks at seminars and conferences.

So far, the project has provided results, indicating that climate change has induced a positive development of wintering waterbird populations in Finland, through northward shifts in wintering ranges. Such a change in wintering range leads also to changed phenology and is a good example of how changed numbers observed and phenology can go hand in hand, without implying direct causal effects. Other results were that short-distance migratory landbirds and species living in forests show declining wintering populations, but both might more likely be habitat-mediated effects. So far, it seems that the main links between phenology and population growth are due to range shifts, or variable survival – i.e. other factors affecting phenology and population size (causing correlation) – rather than direct casual links between phenology and population size.

The primary impact of the project output is academic, in that it enhances our understanding of the system and stimulates further research with a more relevant focus. However, the phenological models applied and developed in three of the ongoing papers are likely to be of use for both researchers and practitioners in the field of applied ecology, also including e.g. agriculture. They both propose guidelines for statistical modelling and for the interpretation of phenological distributions in practice. The proposed project have improved, and will continue to improve European excellence and competitiveness by: 1) enhancing the possibilities to fulfil conservation targets, 2) supporting institutions producing long-term quality data applicable for monitoring, and 3) strengthening the profile of European top research.

The fellowship has had a considerable impact on the researcher’s career development, both through the possibility to do scientific work and through complementary training activities, such as editorial work, peer review of articles, conference organising, and writing job applications. The fellowship has further provided the researcher with an excellent network of skilled people to collaborate with in the future. One of the job applications made was successful and led to a new position in Finland as a Senior Researcher (from September 2013). The main task is to establish an own research group based on external funding. The Marie Curie Intra European Fellowship was one major reason for why the position was received.