Lyanne Brouwer

My interests are broad, but my core interest focuses on social behaviours of animals, and their behavioural adaptations to environmental change, like climate change and urbanization. My work uses approaches from the fields of behaviour, molecular ecology, genetics, and population and demographic modelling based on a thorough understanding of animals in the wild.

• Cooperation and competition among relatives: Individuals in viscous populations (with limited dispersal) live in close proximity with kin, allowing for cooperation among relatives. However, living with relatives can also be costly because of the high risk of inbreeding and the fact that individuals compete with their own kin for space and resources. In 2008, I set-up a new field-based study system on cooperatively breeding red-winged fairy-wrens (Malurus elegans) in south-west WA. All 10 Australian fairy-wrens are cooperative breeders with males staying with their parents to help rear the next brood. In my study species females too stay at home, making this system very suitable to study both the costs and benefits of living with kin. This study has not only resulted in new insights on costs and benefits of group living, but also on some of the sophisticated behaviours that these birds show to avoid these. This study has become a long-term study which allowed us to investigate how changes in climate drives changes in fitness and is now also part of several global scale comparative/meta-analyses on the effects of e.g. climate change. Data from such populations as this one are particularly important, because long-term studies on southern hemisphere species are relatively scarce.

• Explaining inter- and intraspecific variation in behaviour and ecology: Comparing traits within and among species can be a powerful tool to get a better understanding of the variation that exists in the natural world. The fairy-wrens (genus Malurus) are an iconic model system in evolutionary ecology and one of the best-studied bird genera. A large-scale collaboration has resulted in detailed long-term data on 10 species from >20 populations from a single genus. This is an ideal system to investigate inter- and intraspecific variation in ecology and behaviour, without the problems encountered by many other systems where associations might be confounded by phylogeny. For example, we have completed the world’s first comprehensive test of many of the key ecological hypotheses concerning why individuals, populations and closely related species vary in their degree of promiscuity, tested the longstanding idea that conspicuous plumage increases predation risk, and several new projects are on the way. At a global scale, published data can be used for large scale comparative studies. For example, in recent work we combined data from >500 published studies of >300 bird species on promiscuous (extra-pair) mating to examine the patterns with respect to taxonomy, phylogeny and global regions and test the role of several life history and ecological variables.

• Examining space use and movement of endangered black-throated finches.  We study the distribution, habitat use, spatial requirements and nesting ecology of the Southern Black-throated finch Poephila cincta cincta, an endangered species inhabiting the Townsville coastal plains. The generated knowledge will allow for prioritising specific areas for management actions (e.g. weeding, burning) to help conserve this endangered species. 

• Avian body size as an adaptation to climate change. Animals are getting smaller as the climate warms—a change that may help them cope with rising temperatures. Since body size influences thermoregulation, energy use, and life history, these shifts could have major implications for species’ resilience to climate change. This project focuses on Australian birds, drawing on a unique long-term dataset of over 12,500 specimens collected since the 1950s, combined with detailed habitat and climate data, to uncover the environmental drivers of body size variation. This project is in collaboration with Dr Janet Gardner.

• Effects of urbanization on social behaviour and population dynamics: Urbanization involves a drastic change of the environment and is considered one of the most important threats to biodiversity. Although there is lots of attention on how urbanization has affected behavioural changes, the effects on intra-specific behaviours like cooperation and competition has been neglected, despite its importance for fitness. In this EU funded project I use a citizen science approach, combined with new experiments to investigate the underlying mechanisms of changes in social behaviours and the long term population consequences due to urbanization.