Wood Turtle (Glyptemys insculpta) populations are declining in many portions of the species’ native range due to multiple factors that might influence functional connectivity and population genetic structure. We used 13 microsatellite markers to examine patterns of genetic structure in the Wood Turtle across its native range in Eastern and Midwestern North America. For n = 45 collections with 15 or more individuals (total N = 1,258), multiple clustering approaches revealed two major genetic groups corresponding to the midwestern and eastern collections. Interestingly, a sample from lower Michigan clustered with the Eastern group while a sample from the Upper Peninsula of Michigan clustered with the Midwestern group. Evidence of gene flow between these two major groups arose from the most proximate sites near the edges of each group. These results suggest that Lake Superior and Lake Michigan were historically substantial (but perhaps not complete) barriers to gene flow. Our results suggest that Evolutionarily Significant Unit (ESU) status is warranted for Midwestern and Eastern Wood Turtles in North America. Within the eastern group, we observed a strong pattern of clinal allele frequency variation, with evidence of incipient genetic differentiation between multiple collections from the Potomac and Monongahela Rivers from collections in river basins further to the north. Estimation of full-sibling families indicated a range of distance between close family members of 16.8–301 km, suggesting the possibility of extremely long-distance (though rare) dispersal. Mean expected heterozygosity ranged from 0.553 to 0.722 and allelic richness ranged from 4.1 to 6.8. For a species with such a long generation interval (approximately 40 years (yrs)), isolated populations on the low end of this range of both measures of genetic variation might suffer from negative fitness effects of inbreeding and warrant further monitoring efforts. Our results support the management of this species at, or within, the Hydrologic Unit Code-4 (HUC4) subregion scale.
Context Brown-headed cowbirds (Molothrus ater), through brood parasitism, can exert extrinsic population growth pressures on North American songbirds. Cowbird removal programs may reduce parasitism rates on host species but can be expensive and difficult to implement throughout a host species’ breeding range. Aim We estimated cowbird abundance and nest parasitism rates within Kirtland’s warbler (Setophaga kirtlandii) primary breeding range in Michigan, USA, and determined the maximum sustainable parasitism rate for Kirtland’s warblers under several spatially structured cowbird removal designs. Methods We conducted point counts to estimate cowbird abundance and monitored nests to quantify nest parasitism rates during 2019–2021. We used the modelling software STELLA to determine the maximum sustainable parasitism rate for Kirtland’s warblers under different spatially structured cowbird removal scenarios (complete, core-only, and no removal). Key results Cowbird abundance and parasitism rates remained low following cowbird trap closures in 2018. In the simulation study, complete removal was the most robust scenario with no replications having <1000 Kirtland’s warbler males. The core-only removal scenario had a substantially higher sustainable parasitism rate in the peripheral breeding area than the no removal scenario. Assumed hatch-year dispersal distance had the greatest impact on the maximum sustainable parasitism rate in the core-only scenario. Conclusions Low cowbird abundance and nest parasitism following suspension of cowbird removal efforts showed resuming the removal program may not be required in the short-term. If cowbird abundance increases, however, adaptive cowbird removal programs can be used to sustain Kirtland’s warbler populations long-term. Implications Our results indicate that incorporating spatial structure of host species’ habitat into designing cowbird removal programs may minimise costs of cowbird management while sustaining populations of Kirtland’s warbler and possibly other host species that are affected by brood parasitism.
Beaver management requires understanding beaver habitat preferences. Despite the American beaver (Castor canadensis Kuhl, 1820) being relatively common in the upper Midwest region of the United States, there are no beaver habitat relationship models based on this area. We used 1735 colonization events from long-term monitoring data generated by the ChequamegonNicolet National Forest in northern Wisconsin, USA, to determine what geomorphological and biological factors were selected by beavers colonizing new sites. We developed and evaluated prediction performance for three colonization models: geomorphology factors only, geomorphology and vegetation factors, and a full colonization model based on geomorphology, vegetation, and availability of dispersing beavers. Overall, the geomorphology-vegetation-colonizer model was the best model, predicting actual colony locations better than the other two models. Spatially, the landscape open to beaver colonization was a mosaic of streams with suitable and unsuitable habitat. These models improve our understanding of how beaver site selection factors in the upper Midwest region differ from factors identified in the literature for the western and eastern United States. This information may be useful for land managers in this region seeking to spatially target resources for restoring northern forest landscapes such as the Chequamegon-Nicolet National Forest.
This archive contains research data collected and/or funded by Forest Service Research and Development (FS R&D), U.S. Department of Agriculture. It is a resource for accessing both short and long-term FS R&D research data, which includes Experimental Forest and Range data. It is a way to both preserve and share the quality science of our researchers.
Abstract White‐nose syndrome (WNS), caused by the fungal pathogen Pseudogymnoascus destructans (Pd), has driven alarming declines in North American hibernating bats, such as little brown bat (Myotis lucifugus). During hibernation, infected little brown bats are able to initiate anti‐Pd immune responses, indicating pathogen‐mediated selection on the major histocompatibility complex (MHC) genes. However, such immune responses may not be protective as they interrupt torpor, elevate energy costs, and potentially lead to higher mortality rates. To assess whether WNS drives selection on MHC genes, we compared the MHC DRB gene in little brown bats pre‐ (Wisconsin) and post‐ (Michigan, New York, Vermont, and Pennsylvania) WNS (detection spanning 2014–2015). We genotyped 131 individuals and found 45 nucleotide alleles (27 amino acid alleles) indicating a maximum of 3 loci (1–5 alleles per individual). We observed high allelic admixture and a lack of genetic differentiation both among sampling sites and between pre‐ and post‐WNS populations, indicating no signal of selection on MHC genes. However, post‐WNS populations exhibited decreased allelic richness, reflecting effects from bottleneck and drift following rapid population declines. We propose that mechanisms other than adaptive immunity are more likely driving current persistence of little brown bats in affected regions.
In fire-dependent ecosystems, the absence of fire can contribute to a positive feedback in which increased vegetation cover leads to increased accumulation of soil organic matter and nutrient stocks. These changes in turn can influence competitive shifts among plant communities, resulting in increased woody plant establishment, canopy closure, and ultimately leading toward mesophication. Poor soil conditions may be especially important for maintaining the open structure characteristic of pine barrens ecosystems, which are imperiled due to loss of key ecosystem processes such as fire and land conversion to cropland or pine plantations. Our objectives were to determine how soil characteristics are related to recent prescribed fire management, and how soils vary along gradients of current and historic vegetation cover in a barrens-forest mosaic in northern Wisconsin, USA. We sought to understand whether management with prescribed fire shifts soils toward barrens-type soil conditions, and whether soil conditions typify barrens habitat relative to shrub and forest habitat We analyzed organic (i.e. forest floor) and mineral soil horizons collected along gradients of recent prescribed burn history and current (barrens, pine woodlands, brush, and closed-canopy forest) and historic vegetation cover types (barrens, pine plantations, deciduous forests) to investigate the influence of each on specific components of soil fertility. Using a model selection approach, we found forest floor soil properties were most frequently associated with differences in current vegetation cover; for instance, pine woodland sites had greater organic matter stocks than barrens sites, and cation stocks were generally greater at brush sites than barrens and pine woodland sites. Some soil properties, including pH, however, appeared to be driven by prescribed burn frequency. Using ordination techniques to characterize multidimensional characterizations of soils, we identified a soil legacy effect related to historic vegetation cover and land management; native barrens sites had soil characteristics intermediate to restored barrens of pine woodland and deciduous forest origin. Our findings suggest restoration of pine plantations to barrens could benefit from fire activities that enhance consumption of the forest floor, while restoration of deciduous forest and brush habitats will likely be more related to the effective control of hardwood regeneration, after which soil conditions may return to a more archetypical barrens state.
Following publication of the original article Quigley et al. 2019, the authors reported that an incorrect version of Additional 1 has been published. The corrected version of Additional file 1 is attached to this Correction. Additional file 1 was revised to include the following information which was omitted from the original publication: 1) Standard errors associated with all original supplementary tables 2) An additional supplementary table reporting Total C, PyC, and % of C as PyC in ash samples 3) A list of references for the section ‘S1 – Calibrated fuel consumption from maximum paint tag temperature’. Additionally, the authors reported that the standard errors associated with Table 2 in the main text were omitted from the original publication. In this Correction the incorrect and corrected version of Table 2 are shown.
•62% Michigan’s Upper Peninsula amenable to wolves for denning habitat.•Upper Peninsula landscape permeability was high in most areas.•Only 6.7% of the northern Lower Peninsula had high quality den habitat.•Landscape permeability was relatively low in Lower Michigan.
Rapid global climate change is resulting in novel abiotic and biotic conditions and interactions. Identifying management strategies that maximize probability of long-term persistence requires an understanding of the vulnerability of species to environmental changes. We sought to quantify the vulnerability of Kirtland's Warbler (Setophaga kirtlandii), a rare Neotropical migratory songbird that breeds almost exclusively in the Lower Peninsula of Michigan and winters in the Bahamian Archipelago, to projected environmental changes on the breeding and wintering grounds. We developed a population-level simulation model that incorporates the influence of annual environmental conditions on the breeding and wintering grounds, and parameterized the model using empirical relationships. We simulated independent and additive effects of reduced breeding grounds habitat quantity and quality, and wintering grounds habitat quality, on population viability. Our results indicated the Kirtland's Warbler population is stable under current environmental and management conditions. Reduced breeding grounds habitat quantity resulted in reductions of the stable population size, but did not cause extinction under the scenarios we examined. In contrast, projected large reductions in wintering grounds precipitation caused the population to decline, with risk of extinction magnified when breeding habitat quantity or quality also decreased. Our study indicates that probability of long-term persistence for Kirtland's Warbler will depend on climate change impacts to wintering grounds habitat quality and contributes to the growing literature documenting the importance of considering the full annual cycle for understanding population dynamics of migratory species.
Dynamic occupancy models provide a flexible framework for estimating and mapping species occupancy patterns over space and time for large-scale monitoring programs (e.g., the North American Bat Monitoring Program (NABat), the Amphibian Research and Monitoring Initiative). Challenges for designing surveys using the dynamic occupancy modeling framework include defining appropriate derived trend parameters, and providing usable tools for researchers to conduct project-specific sample size investigations. We present a simulation-based power analysis framework for dynamic occupancy models that allows for the incorporation of the underlying environmental space (i.e., as covariates) within a specific study region to inform sample size estimation. We investigate two definitions of temporal trend: (1) a gradual, sustained (linear or nonlinear) change over a period of many years, and (2) an abrupt increase or decrease between two time periods. We draw upon pilot data collected following NABat protocols to inform assumed data generating values in a demonstration of our approach. Due to the complicated parameter structure of dynamic occupancy models, we emphasize the importance of visualizing simulated changes over time based on different parameter settings prior to conducting a power analysis. Our simulations revealed that the linearity of short-term trends (five years in our investigation) conferred higher power with lower sample size than longer trends where occupancy probabilities approached zero (ten years in our investigation). We provide an example of how to use our tools to conduct customized investigations using questions posed by NABat, and in doing so, we shed light on general guidelines that can be applied to programs monitoring species occupancy for other taxa. Importantly, we created an R package to execute our approach for informing program-, species-, and study-specific investigations aimed at identifying changes in species occupancy.
ABSTRACT The robust dispersal capability of the coyote ( Canis latrans ) would suggest a pattern of widespread gene flow across North America, yet historical legacies, dispersal barriers, and habitat affinities may produce or reinforce genetic structure. In the northeastern United States, some coyotes carry genetic signatures from past hybridization events with eastern wolves ( C. lupus lycaon ). These so‐called “coywolves” may have differential predation or competitive success compared with the western origin coyotes with whom they share the contemporary landscape. We sampled coyote populations from New York ( n = 156) and Wyoming, USA ( n = 8) in 2006–2007 and from South Carolina, USA, in 2010 and confirmed regional genetic structure among these coyote populations. Then, within the putative contact zone between the northeastern and western coyote colonization fronts (New York State), we evaluated evidence for broad‐ and fine‐sale genetic structure, and a genetic gradient among New York coyotes using a suite of spatial genetic analyses. Although broad‐scale analyses indicated New York coyotes were highly intermixed, subtle isolation‐by‐distance was detected, and local spatial autocorrelation indicated potentially shorter dispersal distances and larger group sizes for coyotes in the Northeastern Highlands (Adirondack Mountains and foothills). Yet we failed to detect a distinct contact zone between 2 coyote types in New York, indicating that local abundance and ecological context rather than genetic lineage are likely to determine the local ecological effects of coyotes in this region. We suggest that the contact zone between coyote colonization fronts has either eroded or moved further south. © 2019 The Wildlife Society.
Changing climate may impact species through several processes, including phenologic shifts in seasonal timing of food supplies. These temporal changes can create trophic mismatches for species during major life-cycle events such as migration. For long-distance Neotropical–Nearctic migratory songbirds, body condition prior to migration is related to quality and quantity of food supply, which is a function of precipitation and temperature conditions on the wintering grounds. We assessed how future climate-change scenarios might affect wintering habitat of Setophaga kirtlandii (Kirtland’s Warbler) on the Bahamian Archipelago. We used ensembles of general-circulation models to project precipitation and temperature patterns across the archipelago over the winter period, from baseline average until the end of the century. We also used topography layers to define Kirtland’s Warbler winter habitat (open lands) and then made landcover-loss projections for open lands using 1- and 2-m sea-level–rise scenarios. Our results indicate that the Bahamian islands used by Kirtland’s Warbler will become warmer and wetter during the winter months, except during March when central islands are predicted to go through a drying trend. Moreover, our models predict that the greatest habitat loss of coastal open land due to sea-level rise will occur on the northern, lower-elevation islands. If we consider both potential changes in habitat quality and quantity from changing climate, the north-central islands, which currently contain the majority of the wintering population, are likely the critical islands on which to focus climate-adaptation strategies. To help land managers spatially plan for habitat alteration, continued processing of high-resolution imagery is necessary for finer assessments of potential habitat loss, changes in habitat quality, and redistribution of habitats across this island system in response to changing environmental conditions and sea-level rise.
Conservation and recovery of species of concern necessitates evaluating forest habitat conditions under changing climate conditions, especially in the early stages of the delisting process. Managers must weigh implications of near-term habitat management activities within the context of changing environmental conditions and a species' biological traits that may influence their vulnerability to changing conditions. Here we applied established population-habitat relationships based on decades of monitoring and research-management collaborations for the Kirtland's Warbler (Setophaga kirtlandii) to project potential impacts of changing environmental conditions to breeding habitat distribution, quantity, and quality in the near future. Kirtland's warblers are habitat-specialists that nest exclusively within dense jack pine (Pinus banksiana) forests between ca. 5-20 years of age. Using Random Forests to predict changes in distribution and growth rate of jack pine under future scenarios, results indicate the projected distribution of jack pine will contract considerably (ca. 75%) throughout the Lake States region, U.S.A. in response to projected environmental conditions in 2099 under RCP 4.5 and 8.5 climate scenarios regardless of climate model. Reduced suitability for jack pine regeneration across the Lake States may constrain management options, especially for creating high stem-density plantations nesting habitat. However, conditions remain suitable for jack pine regeneration within their historical and current core breeding range in northern Lower Michigan and several satellite breeding areas. Projected changes in jack pine growth rates varied within the core breeding area, but altered growth rates did not greatly alter the duration that habitat remained suitable for nesting by the Kirtland's Warblers. These findings contribute to Kirtland's Warbler conservation by informing habitat spatial planning of plantation management to provide a constant supply of nesting habitat based on the spatial variability of potential loss or gain of lands environmentally suitable for regenerating jack pine in the long-term.
The North American beaver (Castor canadensis) is a managed species in the United States. In northern Wisconsin, as part of the state-wide beaver management program, the Chequamegon-Nicolet National Forest removes beavers from targeted trout streams on U.S. Forest Service lands. However, the success of this management program has not been evaluated. Targeted removals comprise only 3% of the annual beaver harvest, a level of effort that may not affect the beaver population. We used colony location data along Forest streams from 1987-2013 (Nicolet, northeast Wisconsin) and 1997-2013 (Chequamegon, northwest Wisconsin) to assess trends in beaver colony density on targeted trout streams compared to non-targeted streams. On the Chequamegon, colony density on non-targeted trout and non-trout streams did not change over time, while colony density on targeted trout streams declined and then stabilized. On the Nicolet, beaver colony density decreased on both non-targeted streams and targeted trout streams. However, colony density on targeted trout streams declined faster. The impact of targeted trapping was similar across the two sides of the Forest (60% reduction relative to non-targeted trout streams). Exploratory analyses of weather influences found that very dry conditions and severe winters were associated with transient reductions in beaver colony density on non-targeted streams on both sides of the Forest. Our findings may help land management agencies weigh more finely calibrated beaver control measures against continued large-scale removal programs.