CURRENT RESEARCH AREAS

From organismal physiology to species sensitivity

We are interested in the physiology of ectotherms (e.g. energetics, performance, and tolerance) and focus on how adaptive responses, such as phenotypic plasticity and evolutionary responses of performance traits, may contribute to species sensitivity to climate change.

We study a broad range of taxa (insects, reptiles) because some species are better suited to the questions we ask and we attempt to design lab experiments that are informed by (or combined with) field data to enhance ecological relevance.

The Cape Mountain rainfrog Breviceps montanus is susceptible to high water loss when active

Microclimates, behavioural thermoregulation and vulnerability

We explore the extent to which different ectotherms use the heterogeneity of the environment to regulate their body temperature and buffer temperature extremes, or might be constrained by their local environment. We have primarily focused on assessing energetic and non-energetic factors that shape behavioural thermoregulation and how these factors may vary depending on the thermal landscape (e.g. temperature density distribution and configuration) and species ecology. We are also interested in assessing if the failure to depict the spatial and temporal heterogeneity relevant to organisms and incorporate diverse thermoregulatory strategies, can result in misrepresentation of species vulnerability to climate change.

The lizard Agama atra marvels at exploiting rock outcrops to thermoregulate

Global ectotherm trait datasets and macro-physiology

Scaling up from traits to species distributions, community dynamics and ecosystem processes is a challenging (and likely impossible) goal without detailed knowledge of many cause-effect processes and feedback loops underlying specific systems. However, large-scale analyses of species’ traits provide a means to test hypotheses or rules relating to expected ecological patterns and processes. We also explore if these patterns are consistent at different temporal and spatial scales and results can be used to fine-tune experimental tests.

Landscape in the Richtersveld National Park illustrates the importance of scale

Climate x biological invasions interactions

Given the multidimensional nature of global change, we aim to move beyond exploring a single facet of contemporary climate change. We have recently focused on the synergistic effects of climate warming and biological invasions and aim to pursue studies looking at direct and indirect impacts underlying interactions between several drivers of global change in more detail.

Pine tree invasion field site (back – pine plantation; foreground – native vegetation)

The wonders of physics

When I chose the “ecology” career path, I would have not guessed that I would be consulting physics and biophysics books on a regular basis (and I encourage my students to do so too). We often find ourselves delving into first principles when studying heat exchange, metabolism, species space-use, locomotion performance, hearing ability etc. even though we know that species phenotypes and structure-function relationships often do not comply with expectations based on physics alone. Nonetheless, it provides a valuable way to e.g. simulate optimal designs given particular conditions and examine if they are realized in nature, or examine where and when small and large deviations exist among the incredible phenotypic diversity that we find in the natural world. We by no means try to do this alone, but collaborate with skilled engineers and physicists when we can.

Set-up for measuring the skin reflectance of lizards in the Kgalagadi Transfontier Park research station

PROJECT FUNDERS