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Incorporating evolutionary processes into long-term ecological research
Biologists increasingly recognize that ecological and evolutionary processes are closely linked. This is particularly relevant in the context of global change, where environmental conditions may change rapidly, and species may adapt to the novel conditions in a comparable timeframe. Unfortunately, studies that examine the
interactions and feedback loops between evolutionary and ecological processes, particularly in long-term ecological studies, are rare.
We organized a working group that addressed this problem by first identifying barriers that exist to developing evolutionary biology work at LTER sites and, second, identifying possible solutions. In doing so, the working group developed a framework for how to best implement future eco-evolutionary research in a long-term ecological research context. Stay tuned for a publication output from this collaborative effort. For more information, see the LTER network news article published here.
Working group participants at Sevilleta LTER. May 2022.
Photo credit: Scott Colins
Heritability and genetic covariances in fitness traits
Genetic variation is a necessary prerequisite for selection and is known to change between environments (GxE interactions). As such, determining how stressful thermal environments change genetic variance will be fundamental to predicting evolutionary potential. We investigated how genetic variances for life history and morphology traits differed between a benign and stressful thermal environment in rainforest Drosophila.
I am interested in further elucidating how variation in environmental conditions contribute to underlying genetic variation and the role this plays in adapting to climate change.
Sister species of Drosophila from the Australian Wet Tropics. Drosophila birchii is considered a rainforest specialist species and D. serrata is a generalist species. They present as an ideal system to study species interactions and evolutionary dynamics.
Heatwaves and their effects on long-term fitness and thermal tolerance
Heatwaves are increasing in frequency, intensity, and duration as a result of climate change. Yet, the majority of climate change research focuses on the effects of gradual change and ignores the impacts of sudden, extreme events. I am interested in looking at the long-term population-level effects heatwaves may have. Do heatwaves act as hard-selection events on thermal tolerance? How does the intensity and frequency of heatwaves affect long-term population health?
Predicted responses of populations to heatwaves that vary in intensity. The top panel shows predictions to population-level thermal tolerance, and the bottom panel shows predictions to population-level thermal performance curves.
The effect of thermoregulatory behavior on adaptation to climate change
Ectotherms use behavior to reduce exposure to lethal environmental temperatures and to achieve an optimal body temperature for performance (they may move out of the sun to the shade or vice versa). This may cause a coupling of temperature preference and thermal fitness in what is known as the 'Thermal Coadaptation Hypothesis'. It can also slow down the rate of adaptation to the raw environmental conditions, and may reduce the potential for adaptation to climate change. I have investigated the thermal coadaptation hypothesis in ultimate fitness traits in Drosophila and I am interested in learning more about how coadaptation between the two will affect adaptation to climate change.
Experimental evolution studies examining species interactions and rapid adaptation of the thermal niche. This equipment allowed us to manipulate thermal resource space and species interactions over 12 generations.
Novel species interactions and rapid adaptation to climate change
Climate change can alter the distribution of species and cause novel interactions (competition, predation, etc.). We examined whether such interactions can actually drive adaptation to the changing environment and enable coexistence. We used experimental evolution to test whether the thermal niche in two species of Drosophila will evolve into new space when novel competition is induced. I am currently working on analyzing and publishing results from this long-term experimental evolution study. This project provides important conceptual advances in understanding niche evolution.
Field work in the Daintree Rainforest located in the Australian Wet Tropics.
Equipment design
We created an adjustable temperature array to perform controlled ecological and evolutionary studies on thermal physiology. The equipment allows for user-defined thermal environments across a temperature gradient with high accuracy and precision. It is modular and can be scaled to fit the user’s needs to create individual thermal landscapes for use with a variety of species and to answer a diverse amount of questions.
Thermal image of adjustable temperature array showing a temperature gradient of 5°–50°C.
A detailed schematic of the adjustable temperature array.