Theoretical Ecology Group

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PhD Student, MSc
Tom J. Langbehn

What are the evolutionary and ecological mechanisms that govern species range margins?

I work mainly on zooplankton, seabirds and fish in the field of evolutionary ecology and global change biology. I am particularly interested in how individuals, populations and species respond to change and how specific responses through life-history adaptations or species-interactions drive system dynamics.

For my PhD I study "limits to northward range shifts of fish stocks under climate warming". I will use life history modelling to study key biological mechanisms that may prevent fish stocks from extending their range northwards, and to assess their consequences for stock productivity, ecosystem dynamics and resilience.

Bio-climatic envelope models commonly predict future distribution of marine organisms based on their thermal range. In a warming ocean, this results typically in a shift of geographic distribution towards higher latitude.

However, extreme seasonality in photoperiod at high latitudes is unaffected by climate change and enforces a strong selection pressure shaping life-histories and species interactions. The lightscape in marine pelagic ecosystem creates a landscape of risk and opportunity.

In this context I will study the following research questions:

1. How does extreme seasonality, in particular photoperiod, at high latitudes effect predator-prey interactions of fish and zooplankton and what are implications for species range expansions?

2. Does the light regime in polar marine ecosystems act as a biological barrier for mesopelagic fish through life-history trade-offs between energy acquisition, risk taking and survival?

3. What are the optimal life history strategies of Calanus finmarchicus along a latitudinal gradient?

4. How sensitive are those optimal life history strategies towards increasing temperatures and what are the implications for productivity and distribution patterns of Calanus finmarchicus?

To adress this questions I use and array of state-dependent life history models and dynamic optimization algorithms to find optimal life history strategies.

My project is part of the the EU-training network MARmaED - Marine Management and Ecosystem Dynamics under Climate Change.



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