American marten occupancy and activity patterns at the southern extent of their range in the eastern United States.

The relatively recent rediscovery of an American marten (Martes americana) population that was reintroduced over 30 years ago in southern Vermont provides an opportunity to investigate the relative importance of other mesocarnivores, and forest stand (e.g., DBH, downed logs, vertical structure) and habitat variables to their presence on the Green Mountain National Forest. Marten are state-listed as an endangered species in Vermont and occur there at the southern extent of their range in the eastern United States. We collected detection data from camera surveys in 5 km2 units between 2019 and 2021 (December-April; n = 40 units, 238 cameras). We examined activity patterns and applied an occupancy modeling framework to the detection data to assess the relative importance of covariates at unit and camera levels and assess interactions of marten with other mesocarnivores. We did not find any unit-level occupancy models with significant covariates that were better supported than the base model in the single-season unit-level analysis. Distance to the nearest release site was the covariate most supported for detectability at both spatial scales, and marten occupancy at the camera level was positively influenced by the amount of canopy cover. Two species interaction models did not indicate any positive or negative association beyond random with other mesocarnivores and activity patterns among mesocarnivores had substantial overlap. Marten recovery since the time of the reintroduction appears slow, and even 30 years later, the marten distribution is limited and suggests that dispersal is restricted at some level. We recommend a further investigation of the possible impact of other mesocarnivores to juvenile survival or other vital demographic rate (e.g., recruitment) in marten that were not explicitly measured in this study.

Trace element concentrations in water and Clupeonella cultriventris caspia in the Southern Caspian Sea and Assessment of Potential Risk to Human Health.

Despite the fishing pressure on common kilka (Clupeonella cultriventris caspia) and the importance of the Caspian Sea, there are little data on trace element levels in those. Therefore, the concentrations of 27 trace elements were measured in water (n=15) and C. cultriventris (n=1050) collected from the southern Caspian Sea. The concentrations of Cd, Hg, and Zn in the water exceeded permissible limits and posed potential ecological risks to the aquatic biota, especially in the southeastern region of the Caspian Sea. The estimated daily intakes of As, Cd, Co, Hg, Mn, Pb, Sb, and V from the consumption of C. cultriventris were higher than the acceptable daily intake recommended by the JECFA and USEPA. However, the target hazard quotients and hazard index values were lesser than one. It appears that C. cultriventris provides a small amount of essential element nutrition for consumers. In conclusion, this study revealed that consumers are exposed to As, Co, Hg, Mn, Mo, Sb, and, V through the consumption of C. cultriventris. Also, the concentrations of Cd, Hg, and Zn in water showed significant ecological risk.

How spatio-temporal habitat connectivity affects amphibian genetic structure.

Heterogeneous landscapes and fluctuating environmental conditions can affect species dispersal, population genetics, and genetic structure, yet understanding how biotic and abiotic factors affect population dynamics in a fluctuating environment is critical for species management. We evaluated how spatio-temporal habitat connectivity influences dispersal and genetic structure in a population of boreal chorus frogs (Pseudacris maculata) using a landscape genetics approach. We developed gravity models to assess the contribution of various factors to the observed genetic distance as a measure of functional connectivity. We selected (a) wetland (within-site) and (b) landscape matrix (between-site) characteristics; and (c) wetland connectivity metrics using a unique methodology. Specifically, we developed three networks that quantify wetland connectivity based on: (i) P. maculata dispersal ability, (ii) temporal variation in wetland quality, and (iii) contribution of wetland stepping-stones to frog dispersal. We examined 18 wetlands in Colorado, and quantified 12 microsatellite loci from 322 individual frogs. We found that genetic connectivity was related to topographic complexity, within- and between-wetland differences in moisture, and wetland functional connectivity as contributed by stepping-stone wetlands. Our results highlight the role that dynamic environmental factors have on dispersal-limited species and illustrate how complex asynchronous interactions contribute to the structure of spatially-explicit metapopulations.

Landscape genetics of fishers (Martes pennanti) in the Northeast: dispersal barriers and historical influences.

Habitat fragmentation and overtrapping are thought to have resulted in severe population declines for fisher (Martes pennanti) across the northeastern United States, and by the end of the 1930s only 3 remnant populations remained. Subsequent trapping cessation, extensive reintroduction programs, and natural recolonization have helped fishers to reclaim much of their historical range. The degree to which these processes have impacted genetic structure in this species, however, remains unknown. We used 11 microsatellites from tissue samples (n = 432) of fishers to characterize contemporary population structure in light of historical population structure and thus to determine the relative influence of anthropogenic disturbances and natural landscape features in shaping genetic structure of the contemporary population. Our results indicated that 3 well-differentiated contemporary populations are present that correspond well with what would be expected based on their reported history. A course barrier to dispersal appears in the western portion of the study area associated with several lakes including Lake George and Great Sacandaga Lake. Large-scale reintroduction efforts and natural recolonizations have largely had predictable impacts on population structure. An important exception is the substantial impact of the reintroduction of fishers to Vermont.