Research project Long-term change in Swedish bird populations, with special focus on climate and habitat changes
Global warming is affecting the annual cycle of birds with consequences on population trends. Still, there is a need to understand the large variability within and between species, and the mechanisms underlying current changes to foresee future effects on biodiversity of avian species and their ecosystem services.
In this project we investigate the effects of climate change on migratory timing, shifts in wintering areas, breeding time and reproductive success of birds breeding in Sweden, by time-series analysis of ringing data and field studies of common bird species.
Project description
ONGOING PROJECTS
Mechanisms underlying long-term effects of climate change in the most common birds species in Sweden, the willow warbler (Phylloscupus trochilus)
The willow warbler is a ground nesting, long-distance migrant preferring early successional and multispecies forests during breeding. Even though the species is the most abundant birds species in Sweden with around 13,2 million breeding pairs, the southerly populations has experienced a reduction in the population by approximately 50% since 1975. Earlier studies on willow warblers in Europe suggests both migratory timing and population trends to be linked to climate variables both during migration and at the breeding site. However, to date, there are no studies on the relation between fitness parameters, such as reproductive success, and climate variables in the willow warbler. We perform a replication of a detailed field study from the 1980s on phenology and breeding success in the species. By using a spatiotemporal approach we investigate how protandry, breeding time and breeding performance have changed over decades in relation to climate factors at the breeding site and during the migratory route.
Managing forest to increase biodiversity; studies of long-term effects on bird populations
Swedish forests managed for production of wood are monospecific, even-aged and fast growing forest with reduced density of shrubs and vascular plants in the field layers compared to more natural growing forests. Holmen Skog AB has started a management plan within ‘Likstammen Knowledge forest’ in Sörmland, with the purpose of increasing biodiversity by reducing the amount of coniferous trees and increasing the amount of deciduous trees. In 50% of the total area of 500 ha, activities such as cutting down coniferous trees, planting deciduous trees, nature conservation burning of parts of the forests, and construction of water ponds in the area have been implemented during the years 2018-2022. In collaboration with Holmen Skog AB, bird populations are monitored within the area of the ‘Knowledge forests’, following the point method of the Swedish National Standardized bird counts in Sweden. We will evaluate differences and changes over time in bird populations in differentially managed areas. Furthermore, in the autumn 2022 we will put up nest boxes in several areas in both production woods and in areas managed for increasing the amount of deciduous trees, to evaluate eventual effects on the bird community by increased nesting opportunities in the different areas.
Development of a time- and cost efficient method for monitoring bird behavior and abundance by recording of bird song
Due to the rapidity of climate-induced changes in life history events and the geographic spread over which they occur, novel methods are needed to repeatedly track these events efficiently over broad areas. Artificial intelligence techniques have been increasingly utilized to analyse extremely large, intractable datasets in ecology and animal behaviour. Our aim is to develop AI-analyses quantifying ecological relevant events by analysing bird song and calls, both as a method for collecting behavioural data within a species, and for monitoring of bird populations.
Former collaborators
Johanna Hedlund, PhD: Climate change effects on migratory birds and on the ecology and behaviour of the willow warbler. PhD-Dissertation 2015.
Marta Lomas Vega, Post Doc Researcher: Long-term effects of climate change on resident and migratory birds breeding in Sweden - studies of ringing data. 2018-2021.
Samuel Holdar, Supervised master project: Changes in the wintering grounds of common Swedish birds in response to climate change. Stockholm University 2021.
Project members
Project managers
Cecilia Kullberg
Researcher, Docent
Members
Thord Fransson
Professor
David Wheatcroft
Associate Professor
Sven Jakobsson
Professor Emeritus
