Midwest Fish & Wildlife Conference 2019

AUTHORS: Michael Redmer, Michael J. Dreslik, Eric T. Hileman – U.S. Fish and Wildlife Service

ABSTRACT: One of the most consistently cited threats to the Eastern Massasauga rattlesnake (EMR), even on protected lands, is the loss of preferred habitat (sunny, gramminoid-dominated plant communities) to succession from woody plants and invasive species.  The EMR is a conservation or management reliant species, and preferred management techniques (e.g., prescribed fire, mowing, and brush removal) converts and maintains preferred habitat. Life history studies indicate EMR populations can be sensitive to even small amounts of additive mortality, and crucial habitat management actions such prescribed fires present risks. Risks are especially apparent when actions are implemented during periods where populations are most concentrated and vulnerable, such as spring egress, thus creating a paradox amongst habitat and population needs.  Development of recovery implementation strategies will require monitoring to: (1) ensure habitat goals and responses are being achieved, and (2) populations of the EMR respond positively, both in an adaptive management framework. A monitoring protocol initially developed for the U.S. Fish and Wildlife Service, and then modified/implemented by the Illinois Natural History Survey (1999-present) and others, is now or will soon to be used to monitor at least six EMR populations in four states. The protocol gathers data on relative abundance, individuals within monitored EMR populations, and a suite of habitat variables. We propose  that mplementing the protocol at additional select EMR sites where habitat management is planned could be done relatively inexpensively and would allow a direct comparative approach to monitoring range-wide EMR recovery.

AUTHORS: Eric Hileman, U.S. Geological Service; Richard King, Northern Illinois University; Lisa Faust, Lincoln Park Zoo

ABSTRACT: Population viability analysis is a useful tool for comparing alternative management scenarios but requires accurate estimates of demographic parameters. A major threat to the Eastern Massasauga (Sistrurus catenatus) is habitat loss due to encroachment of woody vegetation and invasive species. Current land management practices include prescribed fire and mechanical control to maintain habitat suitability. Although these methods improve habitat quality, they may increase the risk of depredation due to reduced ground cover and can cause mortality if conducted when snakes are active. We estimated demographic parameters from an 8-year study of an Eastern Massasauga population near the range center of the species in southern Michigan. From 2009 to 2016, we captured 826 Eastern Massasaugas 1,776 times. Annual survival increased with increasing age (age 0=0.38, age 1=0.65, age 2=0.67, age >3 females=0.71, age >3 males=0.66), abundance ranged from 84 to 140 adults, annual reproductive frequency was 0.44, and litter size averaged 7.6 offspring. Using these parameter estimates, we created a baseline population viability model that incorporated current prescribed-fire practices. This model projected a stable population with only a 0.2–0.6% probability of extinction over 100 years, suggesting that current management practices at this site are sustainable. Simulations of modest increases in mortality due to fire changed the probability of extinction little over 50 years (<0.7%) but increased probability of extinction up to 24.5% over 100 years in the most pessimistic prescribed-burn scenario. These prescribed-burn simulations may be comparable to burn regimes used at other Eastern Massasauga sites. As information on geographic variation in Eastern Massasauga demography accumulates, population viability can be modeled more widely.

AUTHORS: Matthew C. Allender, Ellen Haynes, Marta Kelly – Wildlife Epidemiology Laboratory, University of Illinois; Sarah J. Baker, Wildlife Epidemiology Laboratory and Illinois Natural History Survey, University of Illinois

ABSTRACT: Snake fungal disease (SFD), caused by the fungus Ophidiomyces ophiodiicola, emerged as a wildlife disease threat over the last 10 years and specifically may threaten the conservation of free-ranging Eastern Massasaugas. Historical records and museum collections have now indicated that SFD was present in some populations in Illinois at least a decade before its description in the literature. The disease syndrome involves clinical signs ranging from minor raised and thickened scales to severe crusts or ulcers on the head and body and can cause death in severe cases. The disease has been found to affect at least 31 snake species. As part of ongoing surveillance for SFD, the Wildlife Epidemiology Lab routinely tests samples for the presence of O. ophiodiicola using qPCR. Since 2013, we have tested over 2000 snake samples from 69 species. In total, 616 positive samples have been recorded across 31 species in 11 states. Despite the apparent sensitivity of pit vipers, only 12.5% (n=99/693) of Eastern massasaugas (Sistrurus catenatus) were positive, whereas nearly 60% (n=218/365) of water snakes (Nerodia sp.) were positive for O. ophiodiicola. Host factors, such as hematology and protein electrophoresis have demonstrated individual Eastern Massasaugas respond immunologically, but the basis for disease protection is unknown. This presentation will synthesize historical and existing knowledge of SFD in Eastern Massasaugas and plans for future efforts. Characterizing the epidemiology of this disease can improve future surveillance and management efforts that may mitigate its effects on snake populations worldwide.

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: Michael J. Dreslik, Illinois Natural History Survey; John A. Crawford, National Great Rivers Research and Education Center; Sarah J. Baker, Illinois Natural History Survey; Christopher A. Phillips, Illinois Natural History Survey

ABSTRACT: For effective conservation and recovery, an adaptive management framework is often best when paired with monitoring population-level responses. In many species, monitoring abundances over time using traditional capture-mark-recapture (CMR) methods is logistically challenging. N-mixture models are an extension of the occupancy and detection probability framework and can estimate abundances across multiple populations. The models use raw abundance counts taken during surveys, model the distributions of capture frequencies, incorporate density-dependent effects and can provide population estimates when recaptures are too few. When validated with traditional CMR estimates, they can provide robust estimates for multiple populations across the landscape. We chose to determine the effectiveness of an N-mixture modeling approach to generate population size estimates for the Eastern Massasaugas within the Carlyle Lake region in Illinois. Our results will be used to determine regional population trends and provide a foundation to assess the effectiveness of conservation actions.

AUTHORS: Christopher A. Phillips, Sarah J. Baker, Michael J. Dreslik – Illinois Natural History Survey

ABSTRACT: Conservation and recovery of declining species are costly endeavors often forcing difficult decisions with limited conservation funds available. Therefore, having a firm understanding of the specific threats a species or population faces can afford the development of more targeted actions. Conservation actions focusing on the most severe threats might have the largest benefit, but they must be achievable, realistic, and measurable. Small population dynamics necessitate the protection of individuals in addition to larger-scale actions to secure the whole population. Over our long-term study of the Eastern Massasauga at Carlyle Lake, we have identified numerous threats to population persistence. We have consistently applied directed conservation actions and reassessed their utility in an adaptive framework. Herein we provide a summary of how we are combating the threats to the Carlyle Lake population through planning and implementation.

AUTHORS: Gregory Lipps, Jr., Nicholas Smeenk – Ohio Biodiversity Conservation Partnership, The Ohio State University

ABSTRACT: Once widely distributed throughout the glaciated portion of Ohio, the Eastern Massasauga is now extirpated at all but 12 sites in the state.  As part of a statewide comprehensive conservation plan for the species, three meetings with resource managers and researchers were convened in 2017-2018 to document the status of each site and prioritize conservation activities.  We developed a worksheet to record multiple metrics that describe the status of populations, habitat conditions, and changes to these values over time.  Occupied Massasauga sites in Ohio can generally be described as having small populations (estimated mean of sites: 59 adults; range: 3-433) but high densities (mean: 5.75 adults/ha; range: 0.7-15).  The amount of available herbaceous habitat at each site varies greatly, but is less than 28 ha for 75% of sites, with a mean of 51% of available habitat at each site known to be occupied (range: 1.5-100%).  The greatest challenge to conserving known populations is maintaining herbaceous habitat through snake-friendly management techniques to control woody and invasive species.  Recovery to more robust populations with predicted long-term viability will require expanding the amount of suitable habitat adjacent to occupied fields (which we have observed to be colonized at two sites) and investigating techniques for augmenting declining populations and repatriating snakes to suitable habitat. 

AUTHORS: Stephanie A. Shaffer, Michigan State University; Henry Campa, III, Michigan State University; Daniel Kennedy, Michigan Department of Natural Resources; Gary Roloff, Michigan State University

ABSTRACT: The eastern massasauga rattlesnake (Sistrurus catenatus catenatus) is a federally threatened species ranging throughout the Great Lakes region. Conservation concerns for the species include declining availability of suitable areas due to habitat degradation and fragmentation. Our goal was to quantify habitat suitability for massasaugas using the Bailey (2010) habitat suitability index (HSI) model and validate this model throughout southern Michigan at 27 20-ha study sites. Sites were selected based on historical or current presence of massasaugas. Following methods described in the HSI model, in 2015 and 2016 we measured vegetation characteristics at 10 - 12 randomly selected locations within each site. As described by the HSI model, we quantified % live herbaceous cover (optimal suitability 60-100%), % dead herbaceous cover (51.5-96%), stem density of trees and shrubs > 3 m (0-58 per ha), basal area of trees and shrubs > 3 m (0-12.1 m2/ha), % area of early deciduous upland (0-57%), and % area of early deciduous wetland (23-73%). To validate the model, we used a resource selection probability function to identify disproportionate use by massasaugas of microhabitat structures defined as important for massasaugas by the HSI model (i.e., % live and dead herbaceous cover, number and average DBH of stems). Based on HSI modeling, habitat suitability rankings for massasauga locations compared to random locations throughout the study sites corroborated structures defined as “optimal” for the species by the HSI model. The resource selection probability function illustrated a positive relationship between massasauga use and the amount of live and dead herbaceous cover, and a negative relationship between use and the number and average DBH of woody stems. Our validation of the Bailey (2010) HSI model indicates that this habitat model is applicable when defining massasauga habitat throughout habitats of varying quality within Southern Michigan.

AUTHORS: Howard K. Reinert, The College of New Jersey; Lauretta M. Bushar, Arcadia University; B. Scott Fiegel, Ecological Associates, LLC; Brandon M. Ruhe, Mid-Atlantic Center for Herpetology and Conservation; Christopher A. Urban, Pennsylvania Fish and Boat Commission

ABSTRACT: Sistrurus catenatus in Pennsylvania has experienced a massive reduction in its distribution over the past 100 years, and it is now limited to four isolated populations. One of the greatest threats to these remaining populations is the succession of open, wetland and meadow habitat (previously maintained by cattle grazing and hay production) to forest. This study took an experimental approach to determine the efficacy of forest removal to re-establish suitable habitat. The study site selected had served as the site of the first telemetric field study of massasaugas in Pennsylvania from 1976-78. At that time the area supported a large population of snakes, and 28 ha of occupied habitat. By 2012, maturation of conifer plantation plantings and encroaching deciduous hardwood forest had reduced the area of open habitat to 2.5 ha. During the winter of 2012, 10 ha of forest was convert to open habitat by a combination of commercial logging, mulching of woody debris, and seeding with native grasses and forbs. Radio tracking of snakes began one year prior to habitat restoration (Spring 2012) and continued for three years after initial restoration activities (to Fall 2015). A total of 24 male, non-gravid female, and gravid female massasaugas were monitored. Prior to restoration activity (2012) and immediately following forest removal (2013) snakes did not utilize the newly altered habitat. In 2014, 9 out of the 15 monitored snakes used the restoration area, and 36.5% of all observations were in the restored habitat. In 2015, all 6 monitored snakes used the restoration area, and 52.5% of all observation were in the restored habitat. Successful foraging, mating, gestation, and overwintering were observed in restored habitat indicating that the restoration successfully re-created suitable habitat. The observations further indicate that massasaugas had the ability to rapidly locate and utilize newly created habitat.

AUTHORS: Bruce Kingsbury, Purdue University Fort Wayne; Jillian Josimovich, US Geological Survey; Monica Matthews, Purdue University Fort Wayne; Sasha Tetzlaff, University of Illinois at Urbana-Champaign; Brett DeGregorio, US Army Corps of Engineers

ABSTRACT: Wildlife translocation involves moving animals to augment depleted populations or to repatriate extirpated ones, or to move “nuisance” animals from places where they might cause harm or be in harm’s way when non-conservation activities threaten them. Many translocations are occurring ahead of our understanding of best practices, and are often unsuccessful as evidenced by increased mortality or departures from a targeted destination. We have been studying the translocation of Eastern Massasauga (Sistrurus catenatus), a small, federally threatened rattlesnake, at a site in Michigan near the northern extent of the species’ range. As part of this ongoing research, we have also been exploring the utility of “soft-release”, which involves temporarily keeping some individuals in an outdoor enclosure at the release site in the hopes that they will acclimate to the new environment more readily than those immediately “hard-released”. To date, we have radio-tracked over 50 translocated and resident (control) massasaugas to investigate their habitat use, spatial ecology and behavior. We report on our findings. Notably, among male massasaugas (the group we had the largest sample for at time of writing), residents had a survival rate of 0.72 (+ SE = 0.21), while hard-released snakes had a reduced annual survivorship of 0.40 (+ 0.20) and soft-released 0.44 (+ 0.18). Evaluations of females are forthcoming. These preliminary outcomes indicate that translocated snakes may experience higher mortalities, and that soft-release does not appear to improve that outcome. Given the increased rates of mortality for individuals moved into unfamiliar territory, nuisance animals should be moved the shortest distances possible, and ideally within their home ranges. Massasaugas translocated out of their home ranges will likely experience higher mortality than residents, and translocation efforts should incorporate that result during planning.

AUTHORS: Christine Proctor, Albert Sarvis – Harrisburg University of Science and Technology

ABSTRACT: Once a widespread and common snake, the eastern massasauga (Sistrurus catenatus catenatus) is protected in every state where it currently occurs and is listed as threatened under the US Endangered Species Act. The use of drones to count wildlife is increasing, however they are primarily used to quantify conspicuous endothermic species. This ongoing study is exploring the potential of drone mounted thermal imaging to increase detection of this cryptic reptile. We hypothesized that thermal imaging captured via a remotely controlled drone will increase our ability to accurately quantify eastern massasauga populations, as compared to more traditional methods. A thermal sensor mounted to a drone was manually flown over a 20-acre managed prairie with a confirmed population of eastern massasaugas in a systematic pattern at an elevation of 10 meters, providing a ground resolution of 1.85 centimeters. Two controllers were used, allowing one person to focus on flying the drone while the other closely monitored the imagery. A third person was directed to the location of a suspected snake for visual confirmation. Once visual confirmation was made, we collected temperature data for both the snake and the ambient environment using a laser thermometer. This allowed for an increased understanding of the minimal temperature difference between the snake and ground required for detection, helping to set target temperature ranges and improve overall detection. During this process we also collected data on thermal signatures of non-snake items such as small mammals, branches, ant hills, and water, helping to train observers on how to interpret the imagery at a higher accuracy. The results from this study have the potential to improve the accuracy of data collection, influencing the future of cryptic reptile detection.

AUTHORS: Crystal Robertson, Andrew Lentini, Rick Vos – Toronto Zoo

ABSTRACT: Much of the habitat for Eastern massasauga rattlesnakes in Ontario is held under private ownership. While the value of engaging private landowners in massasauga conservation has long been recognized, many general education efforts have limited on-the-ground impact. The Toronto Zoo has been involved with massasauga conservation since the 1980s through assurance population management and the development of various outreach resources. The type of messages shared with the public has evolved over time and increasingly requests are fielded about roles played by individual landowners in conserving massasaugas. Over the past four years, Toronto Zoo redeveloped our education materials and landowner engagement offerings to better meet these needs. We now design personalized habitat management guidelines for landowners to enhance their stewardship role. This initiative involves reaching out to landowners through our network of partners and arranging for Zoo staff to gather information on resident snakes during site visits to private properties. The habitat management guidelines offer information on areas of seasonal massasauga activity allowing landowners to plan activities, such as selective tree harvesting, at times that minimize impacts on resident snakes. The guidelines also identify potential habitat enhancement or restoration activities that landowners can undertake with Zoo support. An updated suite of outreach products has been developed to support this initiative and allow participating landowners to spread the word about massasauga conservation. We also utilize visual storytelling in a new video with messaging about massasauga status in Ontario, relevant stewardship actions and local projects being undertaken to support its recovery.  With its accompanying resources, the program now engages the public in safe and relevant actions that reinforce their role in species conservation while developing a new generation of advocates for coexisting with Ontario’s only venomous snake.

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.