Welcome to the Richard B. King Laboratory
What's Happening - Spring/Summer 2012
Abstracts of R. King Lab Presentations
at the World Congress of Herpetology 7
8-12 August, 2012; Vancouver, British Columbia
The Roles of Species Biology, Agency Action, and Public-private Partnerships in Lake Erie Watersnake Recovery and De-listing
Kristin Stanford1,2 and Richard B. King1
1Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115
2Ohio State University F. T. Stone Laboratory, Put-in-Bay, OH 43456
Restricted geographic distribution and declining population size led to listing of the Lake Erie watersnake, Nerodia sipedon insularum, as threatened under the U.S. Endangered Species Act in fall 1999. The Lake Erie watersnake recovery plan, approved in 2003, specified three criteria for delisting. The first, Population Persistence, set overall and island-specific population size requirements for the U.S. islands. The second, Habitat Protection and Management, set overall and island-specific habitat protection requirements. The third, Reduction of Human-induced Mortality, sought to reduce intentional and accidental human-induced mortality to the point where such mortality no longer represents a significant threat. Recovery criteria were met through partnerships among state and federal agencies, universities, non-governmental organizations, and citizen scientists and in fall 2011 the Lake Erie watersnake became the 23rd species to be delisted due to recovery. Timely listing, species biology (including high reproductive potential and a shift in diet to an abundant new prey species), intensive population monitoring, key land acquisitions, and active outreach efforts contributed to rapid recovery. Post-delisting monitoring will occur for a period of five years to ensure that the watersnake population remains stable and that re-listing is not warranted.
Invited contribution to Symposium 17: Conservation successes during times of declining biodiversity: a sample of case studies. L.L.C. Jones, organizer.
12 Years and Over 12,000 Snakes Served: Volunteer Assistance with the Annual Population Census of the Lake Erie Watersnake, Nerodia sipedon insularum
Kristin Stanford1,2 Richard B. King1 and Kent A. Bekker3
1Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115
2The Ohio State University F. T. Stone Laboratory, Put-in-Bay, OH 43456
3Department of Herpetology, Toledo Zoo, Toledo, Ohio 43614
Delisting of the Lake Erie watersnake resulted from annual monitoring which demonstrated that the Population Persistence criterion of the Lake Erie watersnake recovery plan had been met. Monitoring was heavily dependent on efforts of volunteers participating in intensive population censuses each spring and less intensive efforts throughout the active season. Volunteer effort was restricted to sampling (capture effort only) while quantitative measurements (e.g. body size, color pattern, stomach contents) were taken by principle investigators to ensure data quality and consistency. During a decade of annual censuses (2002 – 2011), more than 140 individuals participated (9 – 68 per year, mean = 27). Most volunteers participated during just a single year and often for only a single day but many (35%) participated during multiple years (range = 2 – 10, mode = 3.4). In decreasing order of frequency (weighted by years of participation), volunteers included graduate students, zoo professionals, undergraduate students, regional herpetological society members, federal agency professionals, university professionals, area residents, state agency professionals, regional naturalists and consultants, and high school students. Professional affiliations of volunteers included 20 colleges & universities, 5 state agencies, 5 zoos, 3 regional herpetological societies, 3 regional nature centers and forest preserves, and 2 federal agencies. The use of a diverse group of volunteers provided an opportunity for direct community involvement (locals were encouraged to participate and learn about recovery objectives), an increase in the efficiency of sampling (experienced volunteers provided guidance for novices), an increase in the number of sites sampled simultaneously (experienced volunteers were able to lead teams independent of primary investigators) and an increase in the number of individual snakes captured during the census (number of captures correlates with number of volunteers). The combination of coordinated volunteer efforts, outreach opportunities and data collection enhanced our ability to achieve rapid recovery of this snake.
Invited contribution to Symposium 14: Large-scale and long-term herpetological research and monitoring: the role of citizen scientists and volunteers. R.A. Griffiths and J. Clemons, organizers.
A Detailed Analysis of Survival in the Lake Erie Watersnake, Nerodia sipedon insularum
Kristin Stanford1,2 and Richard B. King1
1Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115
2Ohio State University F. T. Stone Laboratory, Put-in-Bay, OH 43456
Mark-recapture data from 7888 individuals (5792 adults and 2096 sub-adults) spanning 28 years was used to analyze survival and recapture parameters for the Lake Erie watersnake, Nerodio sipedon insularum. Listed as threatened in 1999 under the U.S. Endangered Species Act, this snake was delisted due to recovery in 2011. Data were parsed into subsets for separate multi-model analyses using maximum likelihood methods (Program MARK: CJS & Pradel) to 1) determine whether survival had increased following a rapid shift in diet, 2) identify sources of temporal and spatial variation in survival, 3) provide estimates of sub-adult (neonate and juvenile) survival and 4) provide current estimates of adult survival and population growth for use in demonstrating recovery. Although data from early in this study (1980-1983) are limited, comparisons at one site (North Bass Island) indicated that survival has increased by 17% in males (from 28% in 1980-1983 to 45% in 1996-2008) and 4% in females (from 66% in 1980-1983 to 70% in 1996-2008), providing evidence that watersnake populations have benefited from a shift in diet. Analysis of recent data (1996-2008) showed that spatial variation was an important factor in Lake Erie watersnake adult survival, both among islands and among sites within islands. Sex was also found to influence survival, but with no clear pattern; male survival was higher at some sites and female survival was higher at others. In an effort to obtain survival estimates for younger age-classes, 1674 neonates were wire-tagged immediately after birth and released. The use of TSM (time since marking) models revealed that the inferred age of a snake did influence survival within a single site, increasing from 18% as neonates, to 21-53% as juveniles before reaching adult levels (60-78%). Using data from the 8 best sampled sites over 8 years, the realized population growth rate varied temporally (range: 0.90 to 1.21). A random effects model using these data yielded estimates of mean adult survival of 74% (s2 = 0.024) and mean population growth rate of 1.07 (s2 = 0.014) and provide a baseline for comparison during the 5 year post-delisting monitoring period. Contributed talk
Integral Projection Modeling as a Technique for the Demographic Analysis of Species with Indeterminate Growth
Peter Jones and Richard King
Department of Biological Sciences, Northern Illinois University
The commonly used matrix population projection technique depends on breaking the population of study into discrete classes frequently based on body size. For many species, however, the divisions between size-based classes are arbitrary given that body size is a continuous variable and this can lead to imprecise and inaccurate population models. An alternative to matrix models that shares many of their useful features is the integral projection model (IPM). Rather than separating individuals into discrete classes each with its own set of vital rates, IPMs utilize continuous functions based on the state of an individual (e.g. body size, age). These states can be continuous or discrete. Thus, IPMs are ideal for the population modeling of species with indeterminate growth (e.g. fish, amphibians, and reptiles). IPMs retain some useful characteristics of matrix projection models such as the projected population growth rate from the dominant eigenvalue, stable size distribution and reproductive value from the eigenvectors, and sensitivity and elasticity analysis. Because IPMs do not require the division of individuals into classes, fewer data are necessary for the parameterization of an IPM compared with a matrix projection model. Here we investigate geographic-scale variation in the demography of the Eastern Massasauga (Sistrurus catenatus catenatus) via IPMs. We parameterized IPMs with growth functions from two populations at opposite ends of the Eastern Massasauga’s distribution (southern Illinois and southeastern Ontario). Stable size distributions from the IPMs showed a greater abundance of large adults (>800 mm SVL) in the Ontario population than the Illinois population, a pattern consistent with observed size distributions. This difference is also reflected in the model elasticities, which showed that the highest elasticities for the Ontario population were at a larger adult size than for the Illinois population. IPMs can also be parameterized with different survival and fecundity functions to facilitate more complex comparisons among populations or to explore alternative management strategies. Contributed talk
Initial Characterization of MHC Class IIB Variation in the Eastern Massasauga (Sistrurus catenatus catenatus)
Collin Jaeger, Richard King, and Melvin Duvall
Department of Biological Sciences, Northern Illinois University
The major histocompatibility complex (MHC) plays a key role in the vertebrate immune system by recognizing pathogens. Genes associated with the MHC are often highly variable due to the effects of balancing selection, but genetic drift can also influence MHC variability within small, isolated populations. MHC variation has been characterized in a range of species, representing most of the major vertebrate lineages. However, the MHC of snakes remains poorly understood—no snake MHC sequences have been published to date. The Eastern Massasauga (Sistrurus catenatus catenatus) is listed as threatened or endangered throughout most of its fragmented range. As such, this species represents an ideal model for assessing the relative effects of selection and drift in small, isolated populations. Previous genetic analyses of S. c. catenatus have examined selectively neutral loci (i.e., microsatellites, mtDNA), yet variation in a functional trait (i.e., pathogen resistance) may provide a more meaningful assessment of adaptive potential and long-term population viability. We amplified, cloned, and sequenced a 166-bp fragment (excluding primers) of exon 2 MHC Class IIB, including many of the functionally significant antigen-binding sites. Preliminary results based on a limited number of snakes reveal as many as four unique sequence variants per individual, suggesting the presence of at least two loci. These sequences contain a number of conserved amino acid residues characteristic of functional MHC Class IIB molecules and do not include any in-frame stop codons, indicating they are functional loci. Pairwise differences among the sequences exceed 10% and 25% at the nucleotide and amino acid levels, respectively. Further, we consider the relative roles of selection and drift in shaping MHC variation in Illinois S. c. catenatus in comparison to seven microsatellite loci. These data represent the initial steps towards developing an effective marker of MHC variation in S. c. catenatus. This marker may also provide useful information for conservation efforts involving other snake species of concern and will contribute to our understanding of MHC evolution in an under-represented lineage. Contributed talk
Predicting Climate-Change Induced Distributional Shifts in Great Lakes Region Reptiles
Michael Niiro and Richard King
Department of Biological Sciences, Northern Illinois University
Climate change presents unique challenges to biodiversity policy makers and managers due to potentially significant shifts in the geographic distribution of environmental conditions suitable for population persistence. Reptiles may be especially vulnerable to the effects of climate change because of their thermal dependence sometimes limited dispersal ability. The objectives of this project are to determine the degree to which the distributions of 12 Great Lakes region reptile species are associated with climatic variables and use this information to identify the projected future location of climatically suitable areas under exiting climate change projections. Ecological niche modeling was performed in the program Maxent using a subset of bioclimatic variables from WorldClim selected to reduce overfitting. Climate layers were restricted geographically so that background localities included only areas adjacent to occupied habitat. Presence data for the modeling were obtained from specimen records through HerpNET, museum requests, and requests to state inventories. Models were based on current climate data from WorldClim, and projected into the future using the HadCM3 climate change scenarios. Models were generated for all 12 species, including Regina septemvittata, a natricine snake which currently occurs throughout much of the eastern USA. Minor variations appeared between climate change scenarios, but all scenarios showed the same trend of diminishing habitat suitability as time progresses. By year 2080, much of the western portion of the current range is predicted to become climatically unsuitable for R. septemvittata Contributed talk
Pressure Sensitive Archival Tags: A Novel Method to Monitor Foraging Behavior in Semi-Aquatic Snakes
Richard King1, Kristin Stanford1,2, Tim Reichard3, Lindsey Korfel3, Lauren Flick3
1Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115
2Ohio State University F. T. Stone Laboratory, Put-in-Bay, OH 43456
3Dr. Tim’s Wildlife and Exotics Care, LLC.
To test whether pressure sensitive archival tags could be used to collect detailed information on the foraging behavior of semi-aquatic snakes, we implanted Lotek tags programmed to record pressure every 2 min within the coelomic cavity of two adult female Lake Erie watersnakes (Nerodia sipedon insularum). Snakes were also implanted with radio transmitters to facilitate recapture and tag recovery. These snakes forage for bottom dwelling fish in the near shore waters of Lake Erie but spend non-foraging periods on land. Thus, changes in pressure occur during transitions from non-foraging (terrestrial) to foraging (aquatic) behavior. After several days of apparent inactivity, the two snakes exhibited 15 and 20 inferred foraging bouts over a two week period during late-June and early-July. Inferred foraging bouts ranged from 4 to 168 min with a median of 42 min. Intervals between inferred foraging bouts ranged from 60 to 1920 min (32 hr) with a median of 908 min (about 15 hr). Inferred foraging bouts accounted for 5.0% and 8.5% of the two snakes’ time budgets. Individuals differed in the timing of inferred foraging bouts. One individual foraged predominately during daylight hours (18 of 20 foraging bouts) whereas the other was equally likely to forage during daylight or at night (7 and 8 foraging bouts, respectively). Frequent foraging, as inferred from pressure sensitive archival tags, is consistent with telemetry-based observations of the two snakes included in our analysis as well as the feeding behavior of captive Lake Erie watersnakes and patterns of prey recovery from free-ranging watersnakes. In contrast to other methods, archival tags have the potential to provide far more detailed information on the timing, duration, seasonality, and sex differences of foraging. Contributed talk
Abstracts of R. King Lab Poster Presentations at the NIU Department of Biological Sciences Phi Sigma Research Symposium and NIU Undergraduate Research and Artistry Day, April 2012
Providing Evidence for Multiple Paternity in the Eastern Massasauga (Sistrurus catenatus catenatus) using Microsatellite Analysis
Amber Stedman, Collin Jaeger and Richard King
Multiple paternity is a phenomenon that is both a phylogenetically widespread and ecologically frequent occurrence in numerous species of snakes, lizards, and turtles. This study was conducted with Eastern Massasauga (Sistrurus catenatus catenatus) dams and their offspring from study sites in western Pennsylvania and central Illinois to determine whether there is evidence for multiple paternity in this species. The DNA of each of the dams and their corresponding litters was amplified at 2-7 variable microsatellite loci. Those litters which have more than 2 paternal alleles for a given microsatellite locus provide evidence for multiple paternity. For example, in one litter from central Illinois 3 paternal alleles were present at two distinct loci. Additionally, another litter showed 3 paternal alleles at one locus. Having more than 2 paternal alleles provides evidence for more than one sire and thus, for multiple paternity. Multiple paternity studies may be used to provide answers to questions concerning sexual selection, mating systems, and sperm competition, to name a few, with the overall goal being to understand the evolutionary advantage multiple paternity confers to both male and female snakes.
Differences in Growth and Body Size of Brown Snakes and Common Gartersnakes at Two Sites in Northern Illinois
Tanya O’Brien, Amber Stedman and Dr. Richard King
Conservation biologists often lack basic life history information for species that exhibit reclusive behavior, even when the species is common and widespread. To address this need capture-mark-recapture study of the Brown Snake (Storeria dekayi) and the Common Gartersnake (Thamnophis sirtalis) was conducted at Potawatomi Woods Forest Preserve in n DeKalb County and Nachusa Grasslands in Lee and Ogle County. Potawatomi consists primarily of wet sedge meadow habitat and Nachusa is mesic prairie. Fieldwork involved checking cover boards (recycled conveyor belt) weekly. Snakes were measured to obtain mass and snout-to-vent length (SVL) and each individual was uniquely marked by clipping ventral scales. In 2011, 155 Brown Snakes and 177 Gartersnakes were captured at Potawatomi and 75 Brown Snakes and 64 Gartersnakes were captured at Nachusa. Neonates (snakes born during the 2011 season) of both species were larger at Nachusa than Potawatomi. By October 1st, Brown Snake neonates at Nachusa were 11% longer and 20% heavier than neonates at Potawatomi. Similarly, Gartersnake neonates at Nachusa were 24% longer and 57% heaver than neonates at Potawatomi. Possible mechanisms for these differences may be earlier birth, larger size at birth, or faster growth at Nachusa. Possibly, temperature differences between Potawatomi (cooler) and Nachusa (warmer) are responsible. Soil temperature data will be collected at both sites in 2012 to test this hypothesis. The effect of soil temperature may help estimate impacts of global climate change on these species.