Association of Coloration Mode with Population Declines and Endangerment in Australian Frogs

Abstract: Successful protection of biodiversity requires increased understanding of the ecological characteristics that predispose some species to endangerment. Theory posits that species with polymorphic or variable coloration should have larger distributions, use more diverse resources, and be less vulnerable to population declines and extinctions, compared with taxa that do not vary in color. We used information from literature on 194 species of Australian frogs to search for associations of coloration mode with ecological variables. In general, species with variable or polymorphic color patterns had larger ranges, used more habitats, were less prone to have a negative population trend, and were estimated as less vulnerable to extinction compared with nonvariable species. An association of variable coloration with lower endangerment was also evident when we controlled statistically for the effects of range size. Nonvariable coloration was not a strong predictor of endangerment, and information on several characteristics is needed to reliably identify and protect species that are prone to decline and may become threatened by extinction in the near future. Analyses based on phylogenetic‐independent contrasts did not support the hypothesis that evolutionary transitions between nonvariable and variable or polymorphic coloration have been accompanied by changes in the ecological variables we examined. Irrefutable demonstration of a role of color pattern variation in amphibian decline and in the dynamics and persistence of populations in general will require a manipulative experimental approach.     

Including Spatial Heterogeneity and Animal Dispersal When Evaluating Hunting: a Model Analysis and an Empirical Assessment in an Amazonian Community

Abstract:  Hunting in tropical forests is typically most intense near human settlements, and this creates gradients of decreasing animal densities toward those settlements. Within the context of this spatial pattern, we evaluated the status of game in the hunting grounds of an indigenous community in eastern Ecuador. We constructed a spatially explicit model of hunter-prey interactions that mimicked the hunting in the village and included realistic animal-dispersal rules. We compared predictions from the model with distributions of animal harvest rates and catch per unit effort of 12 game species. Six species were overharvested in part or all of the area, and two other species were probably being overharvested, although high dispersal rates complicated the interpretation. We then compared our method with methods that have been used previously. We argue that because our method provides information about the spatial extent of overharvesting, it could be particularly useful in informing decision makers about where to establish no-take areas and could therefore aid in improving the sustainability of hunting in tropical forests.     

Increasing the Accuracy of Productivity and Survival Estimates in Assessing Landbird Population Status

Abstract:  The conservation of species with declining populations requires information on population demography and identification of factors that limit population growth. For landbird species, an understanding of large-scale population declines often requires assessment of local population processes, including the production of offspring, the survival of those offspring, and adult survival. Population growth has been modeled for several species of landbirds to date, and these studies have provided important information on relationships between population status and population-limiting factors. Several recent studies have illuminated field methods and analytical techniques that can aid in increasing the accuracy of productivity and survival estimates for population models. We reviewed these methods and recommend their implementation, including quantification of the season-long productivity of individuals, collection of empirical data on juvenile survival during the postfledging and overwintering periods, and incorporation of adult breeding dispersal into annual adult survival estimates. Such methods will allow for more accurate assessment of population status and provide a better understanding of the factors on which to focus our conservation efforts.     

ENVIRONMENTAL AUDITING: Exceedance of Critical Loads for Lakes in Finland,Norway, and Sweden: Reduction Requirements for Acidifying Nitrogen and Sulfur Deposition

/ The main objectives of this study were to identify the regions inFennoscandia where the critical loads of sulfur (S) and acidifying nitrogen(N) for lakes are exceeded and to investigate the consequences for depositionreductions, with special emphasis on the possible trade-offs between S and Ndeposition in order to achieve nonexceedance. In the steady-state model forcalculating critical loads and their exceedances, all relevant processesacting assinks for N and S are considered. The critical loads of N and S areinterrelated (defining the so-called critical load function), and therefore asingle critical load for one pollutant cannot be defined without makingassumptions about the other. Comparing the present N and S deposition withthe critical load function for each lake allows determination of thepercentage of lakes in the different regions of Fennoscandia where: (1) Sreductions alone can achieve nonexceedance, (2) N reductions alone aresufficient, and (3) both N and S reductions are required but to a certaindegree interchangeable. Secondly, deposition reduction requirements wereassessed by fixing the N deposition to the present level, in this wayanalyzing the reductions required for S, and by computing the percentage oflakes exceeded in Finland, Norway and Sweden for every possible percentdeposition reduction in S and N, in this way showing the (relative)effectiveness of reducing S and/or N deposition. The results showed clearregional patterns in the S and N reduction requirements. In practically thewhole of Finland and the northern parts of Scandinavia man-made acidificationof surface waters could be avoided by reducing S deposition alone. In thesouthern parts of Sweden some reductions in N deposition are clearly neededin addition to those for S. In southern Norway strong reductions are requiredfor both N and S deposition.KEY WORDS: Acidification; Critical load; Exceedance; Sulfur; Nitrogen;Deposition; Lake     

Crash-Pulse Recorders in Real-Life Accidents: Influence of Change of Velocity and Mean and Peak Acceleration on Injury Risk in Frontal Impacts

Several parameters based on acceleration levels, such as mean or peak acceleration, may correlate with injury risk, or may together with change of velocity, explain the risk of injury, and thus may form the risk function for different kind of injuries. The aim was to study the influence on injury risk for mean and peak acceleration and change of velocity as well as how these correlate with each other. The results from 144 crash-pulse recorders and the diagnoses from driver injuries in real-life frontal impacts were analysed. Change of velocity and mean and peak acceleration were calculated from each recorded crash-pulse. The results and conclusions were that Δv, mean and peak accelerations influence the injury risk, where either high Δv, high mean or high peak acceleration may lead to severe injuries. Mean and peak accelerations together may explain the risk of injury in the studied impacts. When these parameters were combined, a limit could be drawn, above which there was an 89% risk of receiving a moderate or severe injury, while the risk was only 5.5% below that line. The different combinations of impact severity parameters shown in this study are helpful when crash pulses are created for crash tests and computer simulations.