RESEARCH

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The Gunderson Lab addresses two broad and interrelated questions: 1) What makes species and populations vulnerable to anthropogenic global change? and 2) How do organisms evolve in response to climatic variation? We investigate these questions across a range of spatial and temporal scales while applying a variety of approaches, including organismal and molecular physiology, behavior, field ecology, and experimental biology. Details about some specific projects are below. 


Functional Analyses of Climatic Niche evolution During adaptive radiation

The Puerto Rican yellow-chinned anole (Anolis gundlachi) has low heat tolerance relative to most other Puerto Rican species.

Adaptive radiation is a process that leads to the coexistence of multiple closely related but ecologically distinct species. Most textbook examples of animal adaptive radiations focus on the evolution of morphological traits, although physiological evolution can potentially be just as important. We are investigating how physiological evolution under different climatic regimes has contributed to the radiations of Caribbean Anolis lizards (Gunderson et al. 2011; Leal and Gunderson 2012). A key result so far is that, across Puerto Rico and Jamaica, divergence in thermal physiology has happened repeatedly and facilitates species coexistence (Gunderson, Mahler & Leal 2018). 


Investigating global change at the scale of the organism

The intertidal porcelain crab Petrolisthes cinctipes, native to the California coast.

Although anthropogenic warming is a global phenomenon, organisms experience it at a local level. Therefore, investigations of climate change vulnerability are likely to benefit from measurements of environmental conditions taken at the scale at which organisms experience them. We integrate temperature-dependent physiology with biophysical estimates of thermal microhabitats to investigate geographic variation in vulnerability to warming. Study systems have included tropical lizards (e.g., Gunderson & Leal 2012) and intertidal Porcelain crabs on the California coast (currently under review). 


Evolution and Ecological Consequences of Phenotypic plasticity

Acclimation in the heat tolerance of ectotherms does not fully compensate for rising temperatures. From Gunderson & Stillman 2015 Proc. Roy. Soc. B.

Phenotypic plasticity (non-genetic change in traits) could be an important means by which organisms buffer themselves from climate change, but this depends greatly on how plastic organisms are and how variation in plasticity is distributed among taxa. We have conducted meta-analyses to determine magnitudes of, and global patterns of variation in, cold and heat tolerance plasticity among ectotherms (Gunderson & Stillman 2015, Gunderson, Dillon & Stillman 2017). We are also beginning to investigate the functional genomics of thermal plasticity. More to come!


THERMAL ECOLOGY AND THE EVOLUTION OF ANIMAL COLORATION

 Two southwestern fence lizards ( Sceloporus cowlesi ) photographed on dark substrate. The top animal is from the White Sands desert. The bottom animal is from adjacent dark substrate.

Two southwestern fence lizards (Sceloporus cowlesi) photographed on dark substrate. The top animal is from the White Sands desert. The bottom animal is from adjacent dark substrate.

Animal coloration is usually investigated with respect to communication and predator avoidance. However, coloration can also influence animal temperature, with subsequent effects on temperature-dependent physiology, behavior, and ecology. We are studying the thermal effects of color evolution for three species of lizard in the White Sands Desert of New Mexico. All three species have independently evolved blanched coloration on white sand relative to nearby conspecifics on dark soil, likely because it reduces predation risk. Two main questions are being addressed. First, because blanched coloration should decrease body temperatures, have pale animals on white sands also diverged in temperature-dependent physiology and behavior? Second, what are the costs and benefits of blanched coloration in terms of activity and energetics under desert conditions? We are approaching these questions with a combination of field ecology, laboratory experiments, and biophysical modeling of thermal environments.


How temperature shapes The Behavior of ectotherms

A summary of thermal physiology and behavior in a lizard. Behavior is generally more temperature sensitive than physiology (Gunderson and Leal 2015 Am Nat & 2016 Ecology Letters).

Behavior plays a major role in the responses of animals to climatic conditions generally and global change specifically. We are interested in understanding the evolution and ecological consequences of behavioral responses to temperature, including the potential for behavioral thermoregulation to buffer populations from warming (e.g., Gunderson and Leal 2012)and how activity budgets change with thermal conditions (Gunderson and Leal 2015, Gunderson and Leal 2016).


Feather-degrading bacteria and avian coloration

 Swabbing the feathers of an Eastern Bluebird ( Sialia sialis ) for bacteria.

Swabbing the feathers of an Eastern Bluebird (Sialia sialis) for bacteria.

For my Master’s degree I studied feather-degrading bacteria, microbes that live in the plumage of wild birds and can break down the keratin molecules that make up feathers (Gunderson 2008). One project focused on how feather-degrading bacteria influence the appearance of structural (non-pigmentary) plumage coloration in Eastern Bluebirds (Sialia sialis, Gunderson et al. 2009). Another project investigated whether or not feathers colored with melanin pigments are more resistant to bacterial damage than unpigmented (white) feathers (Gunderson et al. 2008).