Linking seasonal migration and dispersal: A large-scale demographic approach in a wild partially-migratory metapopulation

Project Information

MIGRADISP

Grant agreement ID: 895904

DOI

10.3030/895904

Project closed

EC signature date 17 April 2020

Start date 1 September 2021

End date 31 August 2023

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 214 158,72

EU contribution

€ 214 158,72

Coordinated by

NORGES TEKNISK-NATURVITENSKAPELIGE UNIVERSITET NTNU
Norway

Periodic Reporting for period 1 - MIGRADISP (Linking seasonal migration and dispersal: A large-scale demographic approach in a wild partially-migratory metapopulation)

Reporting period: 2021-09-01 to 2023-08-31

Summary of the context and overall objectives of the project

Migration (seasonal movement) and dispersal (movement between birth and first breeding, or between breeding events) are two critical life-history decisions, both taken in response to changing ecological conditions. They could involve similar decision-making processes and covary, thereby profoundly affecting spatio-temporal population dynamics. Yet, we still know remarkably little about how migration and dispersal might be linked and affect each other. While social information (obtained by observing others’ decisions) is known to influence dispersal decisions, we do not know how such information also influences migration. Key outstanding questions are: (1) What is the association between individual migration and dispersal? (2) What are the consequences (in terms of reproductive success) of such an association?

I found that migrating is associated to breeding dispersal, and that this can affect individual reproductive success. However, the direction of this effect on reproductive success depends on the years, so likely on the environmental conditions experienced by migrant and resident birds.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

During this project, I collated ringing and location data from European Shags, analysed them, and prepared a manuscript for publication. This manuscript is currently being revised for publication in Journal of Animal Ecology.
I also prepared and published two other manuscripts on decision making and habitat selection in birds with different ecology but who also shared to aspects of their ecology with the European Shag (one on a colonial bird, and one on a seabird) (see publication list).

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

On the European Shag population, we found unprecedenting evidence that migration can affect later decision, namely Dispersal and that both decisions could be part of a same syndrome.
Besides, we showed that dispersal and migration, seperately and in association have both an impact in individual reproductive success, but this is subject also to changes depending on local environmental conditions.

On the other species, we showed that location of breeding within a colony will impact which space individual utilize to forage and feed, and that individuals breeding in different parts of a same colony will segregate when feeding. This is important to consider also the the project on EUropean Shag which breed in colonies. This led us to differentiate mini-subcolonies when considering dispersal for the main project on European shags.
We also showed that the segregation while foraging of individuals from different subcolonies was important from a conservation aspect. Of people (researchers, stake-holders) do not take into account such segregation in colonial species like the European Shags and others when deriving Areas of Conservation Interest, then they are strongly biasing these Areas and jeopardizing the conservation of the species, or at least the efficiency of conservation measures.

Location of the European Shag colony and examples of Dispersal paths

Conceptual representation of the link between Migration and Dispersal