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Copyright of Regional Studies is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Spatial Economic Analysis is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Regional Studies is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Duff fires (smouldering in fermentation and humus forest floor horizons) and their consequences have been documented in fire-excluded ecosystems but with little attention to their underlying drivers. Duff characteristics influence the ignition and spread of smouldering fires, and their spatial patterns on the forest floor may be an important link to the heterogeneity of consumption observed following fires. We evaluated fuel bed characteristics (depths, bulk densities, and moisture) of duff in a long-unburned longleaf pine ( Pinus palustris Mill.) forest and corresponding spatial variation across 100 to 103 m scales. Fermentation and humus horizon depths both varied (∼100% coefficient of variation) but with moderate to strong spatial autocorrelation at fine scales. Fermentation bulk density varied less than humus bulk density, which varied considerably at fine scales. Fermentation horizons held more moisture (average 49%-172%) and were much more variable than humus following rainfall, which remained stable and relatively dry (average 28%-62%). Humus moisture was moderately autocorrelated at fine scales, but fermentation moisture was highly variable, showing no evidence of spatial autocorrelation under dry, intermediate, or wet conditions. Observations from this study highlight the underlying spatial variability in duff, informing future sampling and fire management efforts in these long-unburned coniferous forests. [ABSTRACT FROM AUTHOR]

One of the major issues when applying truck destination choice models with a large number of alternatives is how to sample a set of non-chosen traffic analysis zones (TAZs) to construct a destination choice set. Despite the large number of studies applying various sampling strategies, the question remains as to what are optimal strategies in model development. This study examined how the sampling strategies affect the performances of truck destination choice models. Two sampling methods (simple random sampling and stratified importance sampling) and four different sample sizes were tested using the truck trip data of Korea. For stratified importance sampling, Moran's I statistics were used to divide the entire study area into multiple strata, and Neyman allocation was used to determine the appropriate number of samples for each stratum. The truck trip productions were distributed by a Monte Carlo simulation, and two measurements of effectiveness (MOEs), average trip length (ATL) and trip length distribution (TLD), were used to evaluate and compare the performance of the destination choice models with respect to the sampling strategy. The results showed that the models using stratified importance sampling with smaller sample sizes performed better than others. [ABSTRACT FROM AUTHOR]

Population genetics has fueled a substantial growth in studies of dispersal, a life-history trait that has important applications in ecology and evolution. Mammals typically exhibit male-biased gene flow, so this pattern often serves as a null hypothesis in empirical studies. Estimation of dispersal using population genetics is not without biases, so we utilized a combination of population genetic methods and simulations to evaluate gene flow within the American badger ( Taxidea taxus (Schreber, 1777)), a highly elusive and poorly understood mustelid. A total of 132 badgers captured between 2001 and 2002 were genotyped at nine microsatellite loci to investigate fine-scale genetic structure consistent with philopatry in females and dispersal in males. Resultant genetic patterns were largely consistent with a panmictic population with little evidence for sex-biased dispersal, and simulations confirmed that our sampling scheme did not substantially impact our statistics. An overall deficiency of heterozygotes was observed across the Lower Peninsula, which indicates either a Wahlund effect, mixing of separate populations, or inbreeding. Our study emphasizes the importance in deciphering between actual behavioral mechanisms and sampling effects when interpreting genetic data to understand other factors that influence dispersal like population density and territoriality. [ABSTRACT FROM AUTHOR]

There is a crucial need to understand the genetic consequences of landscape modifications on continuous populations that could become fragmented, and to evaluate the degree of differentiation of isolated populations that were historically part of the core. Using 15 microsatellite loci, we evaluated the genetic structure of American black bears ( Ursus americanus Pallas, 1780) across a vast, contiguous Ontario landscape (>1 × 106 km2) that largely represents their pre-European settlement distribution. Because geographic barriers are absent, we predicted that isolation by distance would drive genetic structure. We identified three genetic clusters (Northwest, Southeast, and Bruce Peninsula) that were less differentiated than when assessed with mtDNA, suggesting the influence of male-biased dispersal on large-scale genetic differentiation. Isolation by distance ( r = 0.552, P = 0.001) was supported by a weak, clinal variation between Northwest and Southeast, illustrating the challenges to delineate populations in wide-ranging taxa. The Bruce Peninsula cluster, confined to a small area under strong anthropogenic pressures, was more differentiated from neighbouring clusters ( FST > 0.13, P < 0.0001), with a genetic diversity corresponding to disjunct populations of black bears. Our results could be used in landscape genetics models to project the evolution of population differentiation based on upcoming landscape modifications in northern regions of North America. [ABSTRACT FROM AUTHOR]

Copyright of Annals of Forest Science (EDP Sciences) is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)