The possible influence of sapsucker, Sphyrapicus varius varius, presence on insect community structure.

Resources are rarely distributed evenly through space, and in addition many multispecies interactions create patchiness in population densities. The Yellow-bellied Sapsucker, Sphyrapicus varius varius, creates resource patches to which many species aggregate, thereby affecting community structure and population densities in proximity to the sapwell patch. When artificially creating an experimental resource patch in the area of a Sapsucker territory and outside, statistically higher numbers of individuals, numbers of species and relative abundances of insect groups were found in the near experimental stations. These findings corroborate the idea that Sapsuckers influence insect community structure in a local area.http://deepblue.lib.umich.edu/bitstream/2027.42/54385/1/2821.pdfDescription of 2821.pdf : Access restricted to on-site users at the U-M Biological Station

Data from: Formation of a recent hybrid zone offers insight to the geographic puzzle and maintenance of species boundaries in musk turtles

Speciation is the result of an accumulation of reproductive barriers between populations, pinpointing these factors is often difficult. However, hybrid zones can form when these barriers are not complete, especially when lineages come into contact in intermediate or modified habitats. We examine a hybrid zone between two closely related riverine turtle species, Sternotherus depressus and S. peltifer, and use ddRAD sequencing to to understand how this hybrid zone formed and elucidate genomic patterns of reproductive isolation. First the geographic extent and timing of the hybrid zone formation is established to provide context for understanding the role of extrinsic and intrinsic reproductive isolating mechanisms in this system. Then, the strength of selection on taxon-specific contributions to maintenance of the hybrid zone is inferred using a Bayesian genomic cline model. These analyses find a role for selection inhibiting introgression in some genomic regions at one end of the hybrid zone and promoting introgression in many loci at the other. When selective pressures necessary to generate outliers to the genomic cline are considered with the geographic and temporal context of this hybrid zone we conclude that habitat-specific selection likely limits introgression from S. depressus to S. peltifer in the direction of river flow. However, selection is mediating rapid, unidirectional introgression from S. peltifer to S. depressus which is likely facilitated by anthropogenic habitat alteration. These findings indicate a potentially imminent threat of population-level genomic extinction for an already imperiled species due to ongoing human-caused habitat alteration

Locality_East&West Clade

Occurrence data for wood frogs downloaded from public databases, HerpNet and GBIF

BioClim 2.5 clipped

Bioclim 2.5 arc minute WorlClim layers clipped to the United States and Canada

Data from: History matters more when explaining genetic diversity within the context of the core-periphery hypothesis

The core–periphery hypothesis (CPH) predicts that populations located at the periphery of a species' range should have lower levels of genetic variation than those at the centre of the range. However, most of the research on the CPH focuses on geographic distance and not on ecological distance, or uses categorical definitions of core and periphery to explain the distribution of genetic diversity. We use current climate data and historical climate data from the last glacial maxima to develop quantitative estimates of contemporary and historical ecological suitability using ecological niche models. We analysed genetic diversity using 12 polymorphic microsatellites to estimate changes in heterozygosity, allelic richness and population differentiation in 31 populations of the wood frog (Lithobates sylvaticus) spanning the species’ entire eastern clade (33o to 45o latitude) from Alabama, USA, to Nova Scotia, Canada. Our data support predictions based on the CPH. Populations showed significant differences in genetic diversity across the range, with lower levels of genetic variation at the geographic range edge and in areas with lower levels of historical and contemporary ecological suitability. However, history and geography (not current ecological suitability) best explain the patterns. This study highlights the importance of examining more than just geography when assessing the CPH, and the importance of historical ecological suitability in the maintenance of genetic diversity and population differentiation

eastclade_locality

484 occurrence points downloaded from public databases, HerpNet and GBI

BioClim 30s clipped

BioClim 19 climate variables plus altitude clipped to United States and Canada