Effects of urbanization on the population structure of freshwater turtles across the United States.

Landscape-scale alterations that accompany urbanization may negatively affect the population structure of wildlife species such as freshwater turtles. Changes to nesting sites and higher mortality rates due to vehicular collisions and increased predator populations may particularly affect immature turtles and mature female turtles. We hypothesized that the proportions of adult female and immature turtles in a population will negatively correlate with landscape urbanization. As a collaborative effort of the Ecological Research as Education Network (EREN), we sampled freshwater turtle populations in 11 states across the central and eastern United States. Contrary to expectations, we found a significant positive relationship between proportions of mature female painted turtles (Chrysemys picta) and urbanization. We did not detect a relationship between urbanization and proportions of immature turtles. Urbanization may alter the thermal environment of nesting sites such that more females are produced as urbanization increases. Our approach of creating a collaborative network of scientists and students at undergraduate institutions proved valuable in terms of testing our hypothesis over a large spatial scale while also allowing students to gain hands-on experience in conservation science.

Ideas as art. Interview by Dane Cutu.

Three years ago, consultants Laurence Prusak and Thomas H. Davenport asked prominent management thinkers to name their gurus and reported the results in HBR. James G. March appeared on more lists than any other person except Peter Drucker. A professor emeritus in management, sociology, political science, and education at Stanford University, March has taught courses in subjects as diverse as organizational psychology, behavioral economics, leadership, rules for killing people, friendship, computer simulation, and statistics. He is perhaps best known for his pioneering contributions to organization and management theory. March's accomplishments in that field, and in many others, have conferred on him an almost unprecedented reputation as a rigorous scholar and a deep source of wisdom. As University of Chicago professor John Padgett wrote in the journal Contemporary Sociology, "March's influence, unlike that of any of his peers, is not limited to any possible subset of the social science disciplines; it is pervasive." March approaches thought aesthetically; he cares that ideas have "some form of elegance or grace or surprise." His poetic sensibility can be felt in the metaphors he has created over the years--the "garbage can theory" of organizational choice, for instance, and the "hot-stove effect" in learning. In this edited interview with HBR senior editor Diane Coutu, March shares his thinking on aesthetics, leadership, the role of folly, and the irrelevance of relevance when it comes to the pursuit of ideas. He also comments on the fundamental differences between academic and experiential knowledge, underscoring the need for both.

Testing isosource: stable isotope analysis of a tropical fishery with diverse organic matter sources.

We sampled consumers and organic matter sources (mangrove litter, freshwater swamp-forest litter, seagrasses, seagrass epiphytes, and marine particulate organic matter [MPOM]) from four estuaries on Kosrae, Federated States of Micronesia for stable isotope (sigma13C and sigma34S) analysis. Unique mixing solutions cannot be calculated in a dual-isotope, five-endmember scenario, so we tested IsoSource, a recently developed statistical procedure that calculates ranges in source contributions (i.e., minimum and maximum possible). Relatively high minimum contributions indicate significant sources, while low maxima indicate otherwise. Litter from the two forest types was isotopically distinguishable but had low average minimum contributions (0-8% for mangrove litter and 0% for swamp-forest litter among estuaries). Minimum contribution of MPOM was also low, averaging 0-13% among estuaries. Instead, local marine sources dominated contributions to consumers. Minimum contributions of seagrasses averaged 8-47% among estuaries (range 0-88% among species). Minimum contributions of seagrass epiphytes averaged 5-27% among estuaries (range 0-69% among species). IsoSource enabled inclusion of five organic matter sources in our dual-isotope analysis, ranking trophic importance as follows: seagrasses > seagrass epiphytes > MPOM > mangrove forest > freshwater swamp-forest. IsoSource is thus a useful step toward understanding which of multiple organic matter sources support food webs; more detailed work is necessary to identify unique solutions.