Bruce W. Grant

Interfaces between Biophysical and Physiological Ecology and the Population Ecology of Terrestrial Vertebrate Ectotherms

Physiological and biophysical processes interact with a suite of environmental factors to produce important patterns in the population ecology of terrestrial vertebrate ectotherms. We develop a mechanistic approach to understanding the relative contributions of these interactions. Our approach requires a distinction between a life history and a life-history phenotype and allows the incorporation of system-specific trade-offs and constraints in a manner that facilitates the generation of testable predictions for specific populations or sets of populations. We define operant sources of selection and the effects of these averaged over the lifetime of individuals exposed to different environmental factors (available foraging microhabitats, mate availability, preferred egg sites), and synthesize a probabilitistic definition of a life history. We apply this approach to understanding geographic variation in several life-history characters in the saxicolous, iguanid lizard Sceloporus merriami.

Mammalian Metabolic Allometry: Do Intraspecific Variation, Phylogeny, and Regression Models Matter?

Power scaling relationships between body mass and organismal traits are fundamental to biology. Compilations of mammalian masses and basal metabolic rates date back over a century and are used both to support and to assail the universal quarter‐power scaling invoked by the metabolic theory of ecology. However, the slope of this interspecific allometry is typically estimated without accounting for intraspecific variation in body mass or phylogenetic constraints on metabolism. We returned to the original literature and culled nearly all unique measurements of body mass and basal metabolism for 695 mammal species and (1) phylogenetically corrected the data using the fullest available phylogeny, (2) applied several different regression analyses, (3) resampled regressions by drawing randomly selected species from each of the polytomies in the phylogenetic hypothesis at each iteration, and (4) ran these same analyses independently on separate clades. Overall, 95% confidence intervals of slope estimates frequently did not include 0.75, and clade‐specific slopes varied from 0.5 to 0.85, depending on the clade and regression model. Our approach reveals that the choice of analytical model has a systematic influence on the estimated allometry, but irrespective of the model applied, we find little support for a universal metabolic rate–body mass scaling relationship.

The Use of Coverboards in Estimating Patterns of Reptile and Amphibian Biodiversity

Reptiles and amphibians play important roles in ecological communities and can be extremely sensitive indicators of environmental change, despite their cryptic and secretive habits. To estimate herpetofaunal community dynamics potentially attributable to either natural or anthropogenic environmental variation, herpetofaunal biodiversity managers will require specific, standardized, and efficient field sampling methods. One such method involves using arrays of wood and tin coverboards and is the subject of this paper. Studies were conducted on the Savannah River Site in the Upper Coastal Plain of South Carolina from January 1988 to August 1991. Compared with a drift fence/pitfall trap array, the coverboard technique requires less maintenance and sampling effort, but only those reptiles and amphibians using the coverboards at the time of an array check could be encountered. In contrast, live-trapping methods integrate over a longer time period and thereby generate many more encounters per trap. Nonetheless, large numbers of encounters with cryptic reptiles and amphibians can result from coverboard sampling depending upon the study site, coverboard age, time of day, and type of coverboard (i.e., wood or tin). Detailed analyses of hydric and thermal microclimates beneath coverboards suggest specific mechanisms to explain observed differences in herpetofaunal coverboard use. We conclude that the coverboard technique can provide a useful means to quantify patterns in herpetofaunal relative abundance and biodiversity. However, array design and sampling protocol should be carefully selected to minimize sampling biases in encounter probabilities due to subtle differences among herpetofauna in their hygrothermal microclimate preferences.

Design and evaluation of TIEE, a peer‐reviewed electronic teaching resource

“Teaching Issues and Experiments in Ecology” (TIEE) is a peer-reviewed electronic publication designed to help ecology faculty improve their teaching. The Ecological Society of America (ESA) electronically hosts TIEE, which is an important part of the Societys contribution to the BioScience Education Network, a pathway of the National Science Digital Library. A central part of each TIEE “Issue” (mainly for use in lectures) and “Experiments” (for inquiry-based labs) are published figures, genuine datasets, and open-ended investigations. Surveys and interviews show that users teach both at liberal arts colleges (61%) and research universities (26%), and that TIEE provides a much-needed outlet for peer-reviewed education scholarship. Over 75% of respondents to our survey (n = 59) adapted TIEE materials for their courses and 30–50% used TIEE as a model for changing their method of teaching. In addition, over 60% said that publishing in TIEE would be valued in reappointment or tenure decisions. Evaluation fin...