The Experts below are selected from a list of 47556 Experts worldwide ranked by ideXlab platform
Melissa Barsclosel - One of the best experts on this subject based on the ideXlab platform.
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diversification rates are more strongly related to microhabitat than climate in squamate reptiles lizards and snakes
Evolution, 2017Co-Authors: Tiana Kohlsdorf, Melissa Barsclosel, Daniel S Moen, John J WiensAbstract:Patterns of species richness among clades can be directly explained by the ages of clades or their rates of diversification. The factors that most strongly influence diversification rates remain highly uncertain, since most studies typically consider only a Single Predictor variable. Here, we explore the relative impacts of macroclimate (i.e., occurring in tropical vs. temperate regions) and microhabitat use (i.e., terrestrial, fossorial, arboreal, aquatic) on diversification rates of squamate reptile clades (lizards and snakes). We obtained data on microhabitat, macroclimatic distribution, and phylogeny for >4000 species. We estimated diversification rates of squamate clades (mostly families) from a time-calibrated tree, and used phylogenetic methods to test relationships between diversification rates and microhabitat and macroclimate. Across 72 squamate clades, the best-fitting model included microhabitat but not climatic distribution. Microhabitat explained ∼37% of the variation in diversification rates among clades, with a generally positive impact of arboreal microhabitat use on diversification, and negative impacts of fossorial and aquatic microhabitat use. Overall, our results show that the impacts of microhabitat on diversification rates can be more important than those of climate, despite much greater emphasis on climate in previous studies.
John J Wiens - One of the best experts on this subject based on the ideXlab platform.
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diversification rates are more strongly related to microhabitat than climate in squamate reptiles lizards and snakes
Evolution, 2017Co-Authors: Tiana Kohlsdorf, Melissa Barsclosel, Daniel S Moen, John J WiensAbstract:Patterns of species richness among clades can be directly explained by the ages of clades or their rates of diversification. The factors that most strongly influence diversification rates remain highly uncertain, since most studies typically consider only a Single Predictor variable. Here, we explore the relative impacts of macroclimate (i.e., occurring in tropical vs. temperate regions) and microhabitat use (i.e., terrestrial, fossorial, arboreal, aquatic) on diversification rates of squamate reptile clades (lizards and snakes). We obtained data on microhabitat, macroclimatic distribution, and phylogeny for >4000 species. We estimated diversification rates of squamate clades (mostly families) from a time-calibrated tree, and used phylogenetic methods to test relationships between diversification rates and microhabitat and macroclimate. Across 72 squamate clades, the best-fitting model included microhabitat but not climatic distribution. Microhabitat explained ∼37% of the variation in diversification rates among clades, with a generally positive impact of arboreal microhabitat use on diversification, and negative impacts of fossorial and aquatic microhabitat use. Overall, our results show that the impacts of microhabitat on diversification rates can be more important than those of climate, despite much greater emphasis on climate in previous studies.
David F Karnosky - One of the best experts on this subject based on the ideXlab platform.
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the north american ozone air quality standard efficacy and performance with two northern hardwood forest tree species
2005Co-Authors: Kevin E Percy, M Nosal, Warren E Heilman, T Dann, Jaak Sober, David F KarnoskyAbstract:In many forested regions of North America, background O3 levels have been rising despite the fact that hourly maximum concentrations have been decreasing. Unlike Europe, where critical levels based on a response threshold are used to assess risk, Canada and the United States use the best available scientific knowledge balanced by social, economic and political considerations to establish ambient air quality standards for air quality compliance purposes. These ambient air quality standards do not assume the existence of a concentration threshold. The United States (1997) and Canada (2000) established the O3 standard as the 3-year average of the annual fourth highest daily maximum 8-hour O3 concentrations, with target values set at 65 ppb and 80 ppb, respectively. Here, we use 5 years of basal area growth in one control and one O3 Aspen FACE ring to evaluate the performance of five O3 indices including AOT40 and the North American air quality standard. With our data, this standard outperformed AOT40, SUM60, SUM00 and 1-hour maximum as a Single Predictor of growth response. We also evaluate the potential of a standard-based, simple dose response function developed from Aspen FACE to predict productivity in Populus tremuloides and Betula papyrifera.
Ontario Canada - One of the best experts on this subject based on the ideXlab platform.
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I Orai presentations in plenum Session 1,5, and 6:- 7- The North American ozone air quality standard: efficacy and performance with two northern hardwood forest tree species
2016Co-Authors: Ontario CanadaAbstract:Abstract In many forested regions of North America, background O3 levels have been rising despite the fact that hourly maximum concentrations have been decreasing. Unlike Europe, where critical levels based on a response threshold are used to assess risk, Canada and the United States use the best available scientific knowledge balanced by social, economic and political considerations to establish ambient air quality standards for air quality compliance purposes. These ambient air quality standards do not assume the existence of a concentration threshold. The United States (1997) and Canada (2000) established the O3 standard as the 3-year average of the annual fourth highest daily maximum 8-ho & O3 concentrations, with target values set at 65 ppb and 80 ppb, respectively. Here, we use 5 years of basal area growth in one control and one O3 Aspen FACE ring to evaluate the performance of five O3 indices including AOT40 and the North American air quality standard. With our data, this standard outpedormed AOT40, SUM60, SUMO0 and 1-hour maximum as a Single Predictor of growth response. We also evaluate the potential of a standard-based, simple dose response hc t ion developed fiom Aspen FACE to predict productivity in Populus tremuloides and Betula papyrifera. 1
Steven K Seilkop - One of the best experts on this subject based on the ideXlab platform.
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the national environmental respiratory center nerc experiment in multi pollutant air quality health research iii components of diesel and gasoline engine exhausts hardwood smoke and simulated downwind coal emissions driving non cancer biological responses in rodents
Inhalation Toxicology, 2014Co-Authors: J L Mauderly, Steven K SeilkopAbstract:AbstractAn approach to identify causal components of complex air pollution mixtures was explored. Rats and mice were exposed by inhalation 6 h daily for 1 week or 6 months to dilutions of simulated downwind coal emissions, diesel and gasoline exhausts and wood smoke. Organ weights, hematology, serum chemistry, bronchoalveolar lavage, central vascular and respiratory allergic responses were measured. Multiple additive regression tree (MART) analysis of the combined database ranked 45 exposure (Predictor) variables for importance to models best fitting 47 significant responses. Single-Predictor concentration-response data were examined for evidence of Single response functions across all exposure groups. Replication of the responses by the combined influences of the two most important Predictors was tested. Statistical power was limited by inclusion of only four mixtures, albeit in multiple concentrations each and with particles removed for some groups. Results gave suggestive or strong evidence of causatio...
