Current projects in the lab include:
Ecological effects of temperature
Earth’s thermal landscape is rapidly changing, and there is growing recognition of associated changes in the geographic distribution, phenology, and behavior of species. We are therefore interested in understanding how temperature affects ecological systems, and species interactions in particular. We have a variety of specific projects that explore temperature effects in biology, including effects on: movement, behavior, predator-prey interactions, acclimation, and higher levels of biological organization like population, communities, and ecosystems.
Global functional traits database
www.biotraits.ucla.edu is an online resource we co-developed for empirical data on how biological traits respond to environmental drivers (with a particular focus on temperature). This database is described and provided in Dell et al. 2013 and analyzed for the first time in Dell et al. 2011 (with associated commentary). Currently we are using the database to i) test and validate theory about the effect of temperature on predator-prey interactions, ii) explore effects of spatial dimensionality on biodiversity, ii) understand the thermal dependence of ecological performance, iv) determine what factors underly the ability of organisms to acclimate and the structure of their thermal windows.
Allometry in ecology
Body size is a key trait of organisms, influencing a huge number of biological processes central to their ecology and evolution. Because size is so important to individuals, patterns in the body size of co-occurring individuals have important implications for higher levels of biological organization, such as populations and communities. Much of our work investigates size effects in ecology, or at least accounts for such effects. For example, we have explored how the body size of predators and prey affect how they interact, size effects on trophic cascades, patterns of body size in co-occurring species, and even how the size of individuals impacts the properties of entire ecosystems. Understanding the biological mechanisms that determine patterns of body size across levels of ecological organization is especially critical for understanding and predicting effects of human activities that alter size distributions, such as hunting, fishing, and conversion of native plant communities for agriculture or urbanization.
Imaging and automated tracking
A growing component of our research uses automated image-based tracking (Dell et al. 2014) to study how animals move and behave, especially during species interactions. Current projects include: the effect of size and temperature on movement across a corridor, the allometry of behavior in forest food webs, and the role of individual behavior in driving trophic interaction strength.
More tracking videos from our lab can be seen on our YouTube channel.
The biomechanics of movement, behavior, and species interactions
How animals move and behave determines the strength and outcome of species interactions, which determine the types of species that comprise communities and ecosystems. For example, the relative speed, strength, and agility of an interacting predator and prey will determine whether the predator eats or whether the prey escapes, and the outcome of this interaction determines how energy flows throughout ecosystems. We use several approaches to understand the mechanics of species interactions, including laboratory experiments using automated tracking (see above), meta-analysis of published literature, and mechanistic theory. Understanding the mechanics of species interactions provides a critical link between individuals and higher levels of organization, like populations, communities, and ecosystems.
The physiological basis of ecology
A significant component of our research aims to uncover the ways in which the physiology of individuals, specifically metabolic rate, influences the structure and function of ecological systems. Focusing on how physiology constrains how organisms move and behave, together with constrains imposed by size and temperature (see above), should allow uncovering of the general mechanisms that structure ecological systems across levels of organization. This should lead to a more predictive science of community ecology, which is required for understanding ecosystem-level effects of global change.
Island ecology and biogeography
Island ecosystems are excellent model systems for studying ecology and evolution, and are widely recognized as ‘canaries in the mine’ for global change due to their sensitivity to rising sea levels, ocean acidification, changes in atmospheric and sea temperatures, invasive species, and habitat conversion. Our lab is involved with several projects that use the unique biological and physical attributes of islands to address some basic and applied questions in ecology. For example, the phylogenetic structure of bird communities across the Melanesian archipelago, food web assembly during ecosystem development, and patterns of animal movement and behavior from reef to mountaintop.