Session 17: ASIH Stoye Conservation IRoom: Room 206C2022-07-29 08:15 - 09:30 |
| Moderator: Brook Fluker |
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1. 08:15 Effects of Instream Barriers on Population Connectivity of the Kentucky Arrow Darter (Percidae). River Watson*, Center of Excellence for Field Biology, Austin Peay State University; Alexis Culley, Center of Excellence for Field Biology, Austin Peay State University; Matthew Thomas, Kentucky Department of Fish and Wildlife Resources; Stephanie Brandt, Kentucky Department of Fish and Wildlife Resources; Michael Floyd, United States Fish and Wildlife Service; Rebecca Blanton, Center of Excellence for Field Biology, Austin Peay State University riveradelle@gmail.com
Anthropogenic habitat alteration and fragmentation are leading causes of freshwater fish imperilment globally. Habitat fragmentation contributes to population isolation by reducing or preventing gene flow, which contributes to declines in genetic diversity from inbreeding and genetic drift. The Kentucky Arrow Darter, Etheostoma sagitta spilotum (KAD), is a federally threatened darter restricted to headwater streams of the Kentucky River system, where mining and other factors have contributed to extirpation from 45% of its historic localities. A previous range-wide study of KAD found populations located in close proximity to one another within the Daniel Boone National Forest (DBNF) had higher levels of genetic fixation than expected under an isolation-by-distance model. It was hypothesized that recent human-mediated habitat fragmentation contributed to population isolation. We further explore the impact of instream anthropogenic factors including conductivity levels and culvert presence and type on population isolation within the DBNF. Eleven microsatellite loci were used to analyze the impact of instream barriers and land use on gene flow at 14 sites within the DBNF. Five culverts have been measured for a SARP’s Aquatic Organism Passage score across the sampling range, and conductivity levels have been measured at all sampling sites as well as corridors between sites. Results of impacts of these instream features on population connectivity will be presented and discussed. Overall this work will provide a novel, fine scale view of the barriers causing declines in connectivity among and genetic diversity within populations of highly imperiled fish. |
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2. 08:30 The Effects of Surface Mining on Population Connectivity and Genetic Diversity of Etheostoma sagitta spilotum, the Kentucky Arrow Darter. Alexis Culley*, Center of Excellence for Field Biology, Austin Peay State University; River Watson, Center of Excellence for Field Biology, Austin Peay State University; Matthew Thomas, Kentucky Department of Fish and Wildlife Resources; Stephanie Brandt, Kentucky Department of Fish and Wildlife Resources; Michael Floyd, United States Fish and Wildlife Service; Rebecca Blanton, Center of Excellence for Field Biology, Austin Peay State University alexisvculley@gmail.com
The Kentucky Arrow Darter (KAD), Etheostoma sagitta spilotum, is endemic to first and second order headwater streams in the Upper Kentucky River Basin. It is listed as threatened under the Endangered Species Act due to declines in occurrence and abundance, primarily due to extensive habitat degradation from mining activities, across its range. Blanton et al. 2019 (using samples from 2014), using mitochondrial and microsatellite markers, found populations of KAD maintained some level of gene flow across its range, historically (pre-human influence), while contemporary populations were genetically isolated and showed signatures of recent reduction in genetic diversity. Our objectives were to use the same 11 microsatellite markers of Blanton et al. (2019) to assess the impacts of surface mining on population connectivity and genetic diversity in KAD and to describe any changes in genetic diversity metrics over the past 6 years. A total of 208 KAD tissue samples were collected and genotyped from all localities examined by Blanton et al. (2019). Spatial analyses were used to identify and quantify surface mines and other landscape variables that impact targeted KAD populations. Since 1985, an average of 192 km2 was actively mined for coal yearly in the Upper Kentucky River Basin, with peak surface mining activity of 260 km2 in 2007.These mine data will be used to build resistance models in Circuitscape to examine the impact of mining on population level genetic diversity and population isolation observed in this species. Results will be presented and discussed. |
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3. 08:45 Assessing Topeka Shiner (Notropis topeka) Distribution in Missouri, USA Using Environmental DNA (eDNA). Austin Mueller*, University of Central Missouri, School of Natural Sciences; Aaron Geheber, University of Central Missouri, School of Natural Sciences alm33480@ucmo.edu
The Topeka Shiner (Notropis topeka) is a federally endangered stream fish native to the Midwest United States. In the state of Missouri, the Topeka Shiner has undergone a drastic reduction in distributional range over the last half century, leaving few remaining populations. Although conservation and reintroduction efforts have aided in maintaining a small number of these isolated populations, efficient monitoring is critical for future recovery and stability. Furthermore, effective management decisions require a thorough understanding of the current Topeka Shiner distribution in Missouri. Due to the reduction and rarity of Topeka Shiners within their historic distributional range, traditional monitoring efforts (e.g., seining or electroshocking) may be unreliable because of high potential for false negatives. Therefore, the overall aim of this project is to effectively determine the current distribution of Topeka Shiner in select Missouri watersheds using environmental DNA (eDNA) methods. We collected water samples from 71 sites and detected presence of Topeka Shiner at multiple sites where the species has not been documented for 20+ years. Additionally, experimental work testing influences of biomass and downstream distance on Topeka Shiner eDNA detection in artificial streams aided our interpretation of Topeka Shiner detections in the field. Overall, this project provides greater understanding of Topeka Shiner occurrence in Missouri, and in turn, will help focus future monitoring, management, and recovery efforts. |
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4. 09:00 Integrating landscape genomics and habitat suitability assessments to understand the adaptive potential for the Mojave Desert Tortoise across its range. Anjana Parandhaman*, University of Nevada, Reno; Nathan Byer, University of Nevada, Reno; Marjorie Matocq, University of Nevada, Reno; Thomas Dilts, University of Nevada, Reno; Scott Wright, University of Nevada, Reno; Derek Friend, University of Nevada, Reno; Douglas Boyle, University of Nevada, Reno; Scott Bassett, University of Nevada, Reno; Amy Vandergast, University of Nevada, Reno; Todd Esque, University of Nevada, Reno; Jill Heaton, University of Nevada, Reno; Kenneth Nussear, University of Nevada, Reno anjana.parandhaman@gmail.com
The Mojave Desert Tortoise (Gopherus agassizii) is a long-lived species that has suffered population declines yet continues to persist in the fragmented landscape of the Mojave Desert, influenced by changing land use and climate patterns. These stressors have been increasing across its range for decades but have recently accelerated, occurring on a shorter time scale than the length of one tortoise generation. While adaptation and acclimatization may help species like the Desert Tortoise persist under these environmental disturbances, adaptive intraspecific genetic variation has typically been ignored in studies examining extinction risk under forecast models of climate change. The spatial distribution of adaptive genetic variation is a function of historical interactions between genetic drift, natural selection, habitat connectivity, and demography, and so adequately characterizing adaptive genetic variation for sensitive species such as the tortoise requires pairing of high-resolution genomic datasets with habitat modelling. We combined landscape genomic analyses of adaptive genetic variation for the tortoise with concurrent studies examining habitat suitability across its range. We used genome-wide single-nucleotide polymorphisms (SNPs) and multiple outlier detection and Genotype-Environment Association (GEA) approaches to identify loci associated with climatic gradients between core versus edge regions of the species range. Loci identified across approaches were pooled into datasets of potentially adaptive SNPs and initial results indicate that there may be greater adaptive genetic variation across edge regions and military bases. These analyses will be combined with regional scale habitat suitability models to inform areas of conservation action and identify the evolutionary rescue potential for the tortoise. |
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5. 09:15 Evaluating Monitoring Methods to Detect Management Responses in Diamondback Terrapins. Danielle Bradke*, Warnell School of Forestry and Natural Resources, University of Georgia; Brian Crawford, Compass Resource Management; John Maerz, Warnell School of Forestry and Natural Resources, University of Georgia danielle.bradke25@uga.edu
Monitoring is fundamental to management; however, programs rarely evaluate the sensitivity of monitoring approaches to detect population changes. This can result in high uncertainty about whether management actions have been effective. This is particularly important when evaluating actions with high uncertainty or for species with low detection. Among the key threats to diamondback terrapin (Malaclemys terrapin) populations is bycatch mortality in crab pots. The impact of crab fisheries on terrapins has prompted states throughout the species’ range to consider bycatch reduction measures. Our objective was to determine the likelihood that our current monitoring approach using manual seining of tidal creeks would be sufficient to detect a true increase in terrapin survival over a 15-year period with the implementation of bycatch reduction devices. We used a 10-year robust-design dataset of diamondback terrapins captured via manual seining methods to develop a Bayesian model of annual survival, availability, and capture probability. Using this model, we simulated 100 independent datasets assuming that monitoring was conducted over 15 years and that crabbing regulations resulted in a 20% increase in mean survival. The mean estimated effect on survival among all 100 data sets accurately reflected the true increase in survival; however, survival increases were detected in only 28% of simulated datasets. Thus, current monitoring methods are unlikely to detect a real management effect at a single site. Our results indicate that monitoring bycatch reduction will require more robust capture methods. We discuss ways to integrate more monitoring approaches to increase the likelihood of detecting management effects. |