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Bowden J.J.,University of California at San Diego | Hoye T.T.,University of Aarhus | Hoye T.T.,Ecoinformatics and Biodiversity Group | Buddle C.M.,McGill University
Polar Biology | Year: 2013

Fecundity and body size are central fitness-related traits, and their intra-specific responses to environmental variation are receiving increasing attention in the context of climate change. Recent results from Greenland indicate that temporal and spatial variation in body size differences between sexes (sexual size dimorphism) may be widespread among wolf spider species and could be related to climate. Here, we tested whether variation in elevation affected body size of three wolf spider (Araneae: Lycosidae) species in low-Arctic Canada, whether the sexes differed in their response to the cline, and whether changes in local density influenced this relationship. We also tested whether fecundity changed with elevation in two of the species, independent of body size variation. We found a significant sex-elevation interaction for Pardosa lapponica: female size decreased more in response to elevation than that of males. Males and females of Pardosa uintana decreased significantly in size with elevation at a similar rate. Alopecosa aculeata males increased in body size along the gradient while females did not. Pardosa lapponica females, but not P. uintana females, showed significant reduction in fecundity in response to elevation. P. uintana showed significant decreases in body size with increases in its population density. Changes in temperature and potential resource availability along the elevational gradient are probably causing these species- and sex-specific responses. Further summer warming of the region may alleviate current constraints on growth and reproduction of these species although sex-specific responses may affect their population dynamics. © 2013 Springer-Verlag Berlin Heidelberg.

Tovaranonte J.,Ecoinformatics and Biodiversity Group | Blach-Overgaard A.,Ecoinformatics and Biodiversity Group | Pongsattayapipat R.,Queen Sirikit Botanic Garden | Svenning J.-C.,Ecoinformatics and Biodiversity Group | Barfod A.S.,Ecoinformatics and Biodiversity Group
Nordic Journal of Botany | Year: 2015

Species distribution modeling has been widely used to address questions related to ecology, biogeography and species conservation on global and regional scales. Here, we study palms (Arecaceae) in a tropical biodiversity hotspot (Thailand) using species distribution modeling to assess range-limiting factors and estimate distribution and diversity patterns based on a comprehensive compilation of occurrence records. We focused on palms as a model group due to their key-stone importance for ecosystem functioning and socio-economics. Different combinations of climatic, non-climatic environmental and spatial predictors were used. The most accurate models as indicated by the 'area under the receiver operating characteristic curve' (AUC) statistic were those that combined all predictors. The four strongest single predictors of palm species distributions were, in decreasing order of importance, 1) latitude, 2) precipitation of driest quarter, 3) annual precipitation, and 4) minimum temperature of the coldest month, suggesting rainfall patterns and latitudinal spatial constraints as the main range determinants. Overlaying the predicted distributions revealed that potential palm hotspots are situated in the provinces of Satun and Yala in southern Thailand where vast areas remain relatively open to the discovery of new palm records and perhaps even new species. © 2013 The Authors.

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