Midwest Fish & Wildlife Conference 2019

AUTHORS: Roshelle Hall (Masters in Biology); Dr. Daniel Gonzalez-Socoloske (Associate Professor); Dr. Peter Lyons (Associate Professor) – Andrews University

ABSTRACT: The Eastern Massasauga rattlesnake (Sistrurus catenatus; EMR) is a small robust pit viper currently found in nine states and the province of Ontario, Canada.  Wetland habitats have experienced significant destruction and fragmentation by humans; as a result, the current distribution of the EMR is a fraction of its historic distribution. For this reason, the EMR has been federally listed as threatened.  In general, little is known about the current distribution of this rattlesnake (in the southwest corner of Michigan), the size of local populations or their stability and genetic diversity. Much of this knowledge is based upon historical data.  Our purpose was to update the available information on the current status in Berrien County and one Van Buren County site. This was done through presence/absence surveys, evaluation of potential threats at each site visited and genetic analysis at the haplotype level.  Through our field surveys we confirmed presence of EMRs at 4 of the 6 historic locations surveyed.  Current threats at these sites include human encroachment, road traffic, and general health of the particular habitat.  Despite the relatively small sample size and isolated populations in these counties,  the haplotype diversity discovered appears to be high in comparison to the rest of their range. 

AUTHORS: Scott Martin, H. Lisle Gibbs – Department of Evolution, Ecology, and Organismal Biology, The Ohio State University and Ohio Biodiversity Conservation Partnership, The Ohio State University; Greg Lipps, Ohio Biodiversity Conservation Partnership, The Ohio State University

ABSTRACT: Effective management of rare species relies on knowing the spatial structuring and connectivity between populations. For example, the ability of individuals to move between populations increases the likelihood of long-term persistence of a species by promoting gene flow and buffering populations against stochastic demographic events, whereas a lack of movement leads to population isolation and an increase in genetic drift. Genetic markers, such as single nucleotide polymorphisms (SNPs), can be used to determine if individuals successfully disperse between populations with a high degree of resolution. We used genome scale genetic markers to study the population connectivity of the federally threatened Eastern Massasauga (Sistrurus catenatus) which exists across the US portion of its range in small isolated populations. Specifically, we generated ddRADseq data for 114 individuals from sixteen fields comprising six putative populations in NE Ohio. We then calculated pairwise genetic distances between all sites. These distances were used to optimize resistances maps based on elevation and landcover in R. The top resistance values were then added to the program ‘Circuitscape’ which uses circuit-theory based modelling to map areas critical to maintaining genetic connectivity between sites while allowing for multiple pathways between sites. Our results show how genetic data can be used to determine spatial structuring in a patchily distributed species, and to map critical corridors that maintain connectivity between sites.

AUTHORS: Nathan Kudla, Grand Valley State University; Eric McCluskey, Grand Valley State University; Jen Moore, Grand Valley State University

ABSTRACT: Populations with low gene flow can become negatively influenced by increased levels of inbreeding, lower genetic diversity, and reduced adaptive potential. Landscape genetics allows for spatial and genetic information to be analyzed simultaneously to better understand how the landscape influences gene flow. This information is then used to estimate population connectivity and identify landscape features which act as barriers or promoters of gene flow. The eastern massasauga rattlesnake (Sistrurus catenatus) is a federally threatened viper typically found in wetlands throughout the Great Lakes region. Due primarily to a loss of habitat, many remaining populations are small and isolated. This lack of connectivity brings into question the survival of these populations into the future. Unlike many other populations, the eastern massasauga rattlesnakes on Bois Blanc Island, Michigan live in a relatively undisturbed habitat with a potential for high connectivity across the 88 km² landscape. We used landscape genetics to estimate genetic connectivity of eastern massasauga rattlesnakes across Bois Blanc Island. 109 Individuals were genotyped at 16 microsatellite loci and pairwise genetic distances were calculated as the proportion of shared alleles (D_ps). We used resistance surface modeling to assess how the island landscape is influencing gene flow. Our results will provide insight into how eastern massasauga rattlesnake populations function in areas with limited human presence and minimal landscape alteration and if population connectivity can be maintained across a well-connected landscape with high abundance.

AUTHORS: Eric McCluskey, Grand Valley State University; H. Lisle Gibbs, The Ohio State University; Scott Martin, The Ohio State University; Jennifer Moore, Grand Valley State University

ABSTRACT: The loss of genetic diversity in fragmented landscapes is a major concern for threatened and endangered species. Reductions in patch size and connectivity are expected to further erode genetic diversity for isolated populations. In order to preserve genetic diversity, most conservation efforts are focused on ameliorating the connectivity issue via corridor creation to promote gene flow. Addressing the potential loss of genetic diversity from a habitat perspective is less straightforward because the relationship between habitat area and genetic diversity has not been thoroughly investigated across taxa in the field of landscape genetics. We examined this relationship for a federally threatened species, Eastern Massasauga Rattlesnake (Sistrurus catenatus), that is largely restricted to isolated populations making loss of genetic diversity a pertinent management issue. We obtained genetic diversity data from populations across the range that varied in habitat amount and land use history. A subset of these are in states (IL, MI, and OH) with historic land cover datasets, derived from Public Land Surveys conducted prior to most land alterations associated with European colonization and expansion. We evaluated the relationship between various habitat metrics and genetic diversity across multiple spatial and temporal scales. Across the range, genetic diversity does not appear to be directly related to habitat area at the patch level within contemporary environments. We did detect a lasting genetic signal from historic habitat levels at a broad scale. Populations with high habitat area estimates from the 1800s exhibited moderate to high genetic diversity, despite dramatic habitat loss in some cases. These results demonstrate a certain degree of genetic resiliency among historically robust populations. Hence, even small, remnant populations may still harbor allelic diversity that could be maintained with proactive habitat management to boost population size and connectivity.

AUTHORS: Alex Ochoa, Michael Broe, H. Lisle Gibbs – Ohio State University

ABSTRACT: Small isolated populations of endangered species can experience genetic costs through the loss of adaptive variation and/or the accumulation of deleterious mutations through genetic drifts.  The endangered Eastern Massasauga Rattlesnake (Sistrurus catenatus) occurs in isolated populations with small effective sizes throughout its range in the U.S. and Canada, but little is known about the levels of adaptive genetic variation in existing populations.  Here, we used DNA capture probes and Next Generation Sequencing to assess the genetic diversity of venom genes in 93 Eastern Massasauga Rattlesnakes from 12 populations in Ohio, Pennsylvania, New York, Illinois, and Ontario.  Specifically, we characterized the genetic diversity of genes encoding PLA2, BPP, CRISP, SVSP, and SVMP venom proteins, as well as an additional set of ~1400 non-toxin and neutral loci.  Within populations, we find that variation—defined as the presence of nonsynonymous single nucleotide polymorphisms in venom genes—is common and not related to effective population sizes, as determined from neutral genetic markers.  This suggests that small populations of this species still retain high levels of adaptive genetic variation despite the impact of strong genetic drift. In contrast, levels of population divergence in toxin and non-toxin loci are similar, thus making the roles of selection versus genetic drift in maintaining population differences in venom gene alleles uncertain.  Broadly, we discuss the implications of our results for management activities for this endangered snake from a conservation genetics perspective.

AUTHORS: Kate C Donlon, William E Peterman – School of the Environment and Natural Resources, The Ohio State University

ABSTRACT: A leading contributor to the global decline of amphibians is habitat loss and alteration. While it is clear habitat alterationcan negatively impact the persistence of an organism on the landscape, many studies do not offer insight into population-level implications. Disturbed systems provide the opportunity to investigate the response of populations to habitat alteration post-disturbance. Industrial surface mining, also known as strip mining,is an example of extreme anthropogenic disturbance. The initial disturbance from surface mining can cause direct wildlife mortality and the displacement of species capable of moving away from the impacted area. Long-term effects are associated with changes to the vegetation and contour of the landscape. Prior to the Surface Mining Control and Reclamation Act of 1977 restoration requirements were minimal and infrequently enforced. Historically, strip mined land was often abandoned or only partially restored through the planting of trees on soil banks. Despite the extensive habitat destruction caused by the removal of layers of soil and rock to expose seams of coal for extraction, plethodontid salamanders have been found occupying reforested mine land that was abandoned prior to 1977 in Ohio. These populations provide an opportunity to study the long-term response of terrestrial salamanders to extreme anthropogenic disturbance. The goal of this project is to study the population genetics of terrestrial Northern Ravine salamander, Plethodon electropmorphus, across a heterogeneous landscape disturbed by strip mining. Comparisons between mined and un-mined sites will be made to infer the long-term impact strip mining has had on sensitive species’ ability to recoverfrom habitat disturbance. Population genetic parameters will be generated from microsatellite data from individuals sampled onmined and undisturbed reference sitesin Tuscarawas County, Ohio. Population genetic parameters will provide insight into population level implications ofextreme habitat disturbance.

AUTHORS: Anastasia Rahlin, University of Illinois at Urbana-Champaign; Mark Davis, University of Illinois at Urbana-Champaign; Matthew Niemiller, University of Alabama in Huntsville

ABSTRACT: Wetland fragments in Illinois support over 100 bird species, 15 of which are state threatened and endangered. Wetland birds are of particular concern under the Illinois State Wildlife Action Plan due to the lack of information about their population sizes and distributions. Traditional playback methods fall short in elucidating cryptic wetland bird occupancy due to small body sizes, infrequent vocalizations, and unique habitat requirements. In this study, we investigated whether environmental DNA (eDNA) methods could be used to detect multiple rail species, and also hypothesized that taking environmental DNA samples over time would allow us to temporally track rail migration. We collected and filtered water samples from four sites from northern Illinois. We collected and purified DNA from filters using a Qiagen DNeasy kit, and quantified extracts on a Qubit 3.0 fluorometer. We amplified a short fragment of the mitochondrial cytochrome oxidase subunit 1 locus using newly designed degenerate bird primers. We positively detected eDNA in our samples, with Qubit concentrations ranging from 1.30 ng/ml to 80.3 ng/ml. As expected, negative control samples collected in the field yielded no eDNA. Degenerate primers positively detected GBHE and SORA DNA extracted from liver controls, with band fragment sizes of approximately 125 base pairs. Degenerate primers also yielded multiple ~125 bp bands, showing strong evidence for wetland bird DNA detection from eDNA samples. Samples were sequenced on a MiSeq using degenerate bird and vertebrate primers. We focused on analyzing Illumina sequencing data for four species: Sora, King Rail, Virginia Rail, and Least Bittern. Our analyses yielded positive detections for multiple rail species. Least Bitterns were not detected. Ongoing work focuses on adding sampling sites in northern Illinois, increasing sampling duration, and taking soil eDNA samples.