Developing a predictive modelling capacity for a climate change-vulnerable blanket bog habitat: Assessing 1961-1990 baseline relationships

Aim: Understanding the spatial distribution of high priority habitats and developing predictive models using climate and environmental variables to replicate these distributions are desirable conservation goals. The aim of this study was to model and elucidate the contributions of climate and topography to the distribution of a priority blanket bog habitat in Ireland, and to examine how this might inform the development of a climate change predictive capacity for peat-lands in Ireland. Methods: Ten climatic and two topographic variables were recorded for grid cells with a spatial resolution of 1010 km, covering 87% of the mainland land surface of Ireland. Presence-absence data were matched to these variables and generalised linear models (GLMs) fitted to identify the main climatic and terrain predictor variables for occurrence of the habitat. Candidate predictor variables were screened for collinearity, and the accuracy of the final fitted GLM was evaluated using fourfold cross-validation based on the area under the curve (AUC) derived from a receiver operating characteristic (ROC) plot. The GLM predicted habitat occurrence probability maps were mapped against the actual distributions using GIS techniques. Results: Despite the apparent parsimony of the initial GLM using only climatic variables, further testing indicated collinearity among temperature and precipitation variables for example. Subsequent elimination of the collinear variables and inclusion of elevation data produced an excellent performance based on the AUC scores of the final GLM. Mean annual temperature and total mean annual precipitation in combination with elevation range were the most powerful explanatory variable group among those explored for the presence of blanket bog habitat. Main conclusions: The results confirm that this habitat distribution in general can be modelled well using the non-collinear climatic and terrain variables tested at the grid resolution used. Mapping the GLM-predicted distribution to the observed distribution produced useful results in replicating the projected occurrence of the habitat distribution over an extensive area. The methods developed will usefully inform future climate change predictive modelling for Irelan

Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity

Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.Animal science

Sex-specific survival of adult common eiders in Nova Scotia, Canada

Common eiders (Somateria mollissima) are large sea ducks with a circumpolar distribution and have high cultural significance to sport hunters and indigenous peoples in many countries. Their gregarious habits, including colonial breeding and forming large flocks during migration and winter, make eiders susceptible to environmental stressors during breeding and non-breeding seasons. Our objective was to assess whether low adult survivorship could be contributing to suspected local population declines in Nova Scotia, Canada. We banded molting male and breeding female common eiders along the marine coastline of Nova Scotia and recaptured them in later years. We found that from 1997 to 2011, when males and females were banded, male survival (S) was high (S = 0.92; 95% CI = 0.87–0.95), whereas female survival was approximately 10% lower (S = 0.83; 95% CI = 0.78–0.87) and at a level comparable to what has been reported in other regions of the world where eider populations are thought to be in decline. Recovery rates (f) of harvested male and female eiders were indistinguishable (f = 0.013; 95% CI = 0.010–0.016), suggesting that lower female survival is attributable to factors other than hunting. Supplementary analyses using a longer-term data set for females only (1978–2011) and including live recapture data indicated that female survival rates have not changed markedly during the past 40 years and that the emigration rate from colonies is low (∼6%). We conclude that to successfully conserve this population, sources of non-harvest female mortality should be investigated and used to develop targeted management solutions. We speculate that one of those sources of mortality is predation on females at breeding colonies, notably from eagles and mustelids. © 2016 The Wildlife Society