Tuesday, June 6, 2017
14:00 - 15:45

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14:00 - 14:15: / 305A PERSPECTIVES ON NORTH AMERICAN CRAYFISH CONSERVATION PAST/PRESENT

6/06/2017  |   14:00 - 14:15   |  305A

PERSPECTIVES ON NORTH AMERICAN CRAYFISH CONSERVATION PAST/PRESENT The North American crayfish fauna is the richest in the World. When coupled with their significant ecosystem impacts, the conservation of this unique fauna should be of upmost importance. This talk will provide a primer for subsequent presentations in the crayfish conservation and ecology special session and will address three main topics: 1) an overview of crayfish conservation efforts in the United States over the past 35 years, specifically addressing successes and failures; 2) the current state of crayfish conservation; and 3) the potential impact of past and emerging technologies on crayfish conservation and the future direction of efforts by astacologists and resource agencies.

Chris Taylor (Primary Presenter/Author), Illinois Natural History Survey, cataylor@illinois.edu;


Guenter Schuster ( Co-Presenter/Co-Author), Emeritus, Eastern Kentucky University, Guenter.Schuster@eku.edu;


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14:15 - 14:30: / 305A ENHANCED CONSERVATION THROUGH THE UNDERSTANDING OF CRAYFISH THERMAL ECOLOGY

6/06/2017  |   14:15 - 14:30   |  305A

ENHANCED CONSERVATION THROUGH THE UNDERSTANDING OF CRAYFISH THERMAL ECOLOGY Information elucidating the thermal ecology of crayfish is valuable to managers tasked with conserving crayfish communities. Thermal ecology informs topics from physiological process and growth, through distribution and invasive species spread. My objectives were to review the crayfish thermal ecology literature and explore relationships between temperature and species distributions. I located 56 studies that reported information on thermal tolerance, thermal preference, or optimal growth. These studies covered 6% of species worldwide and included 10 of the 30 genera. Information vital to replicating experiments was often absent and poor standardization of methods and analytical approaches impaired my ability to thoroughly investigate broad ecological patterns. However, I did observe a significant negative relation between absolute latitude and optimal growth temperature. Increased methodological standardization and exploration of novel approaches will enhance the value of future studies seeking to understand crayfish thermal ecology.

Jacob Westhoff (Primary Presenter/Author), Missouri Department of Conservation, jacob.westhoff@mdc.mo.gov;


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14:30 - 14:45: / 305A CRAYFISH CONNECTIONS: LINKING ECOLOGY AND HYDROGEOLOGY IN ALABAMA’S BLACK BELT PRAIRIE USING BURROWING CRAYFISH SITE PREFERENCE

6/06/2017  |   14:30 - 14:45   |  305A

CRAYFISH CONNECTIONS: LINKING ECOLOGY AND HYDROGEOLOGY IN ALABAMA’S BLACK BELT PRAIRIE USING BURROWING CRAYFISH SITE PREFERENCE A unique group of invertebrates with adaptations for burrowing into benthic and terrestrial habitats, crayfish provide a vital link to the health of aquatic and terrestrial environments. Because of sampling difficulty and small sample size, one faction of the crayfish community that remains underrepresented is primary burrowing crayfish, which spend most of their lives in subterranean burrows far from surface water. I am using field surveys to determine what combination of environmental variables influence burrowing crayfish site selection most significantly in a Black Belt Prairie watershed: soil characteristics, ground cover, floodplain connectivity or groundwater characteristics. I am also assessing peak crayfish activity periods by using motion triggered photography to determine what may serve as an environmental cue to cause crayfish to exit their burrows most frequently: air temperature, rainfall amount or photoperiod. Following the identification of preferred burrowing sites and peak activity periods, I will develop an occupancy model for burrowing crayfish in the Black Belt Prairie region of Alabama. This research will help guide a watershed management plan for similar stream systems that will benefit both aquatic and terrestrial communities.

Rebecca Bearden (Primary Presenter/Author), University of Alabama, rabearden@crimson.ua.edu;


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14:45 - 15:00: / 305A HYDROLOGIC CONTROLS OF BURROWING CRAYFISH DISTRIBUTIONS

6/06/2017  |   14:45 - 15:00   |  305A

HYDROLOGIC CONTROLS OF BURROWING CRAYFISH DISTRIBUTIONS Anthropogenic activities have created a crisis for freshwater taxa, particularly crayfish, which rank as the second most imperiled aquatic group in North America. Burrowing species compose only 15% of North American crayfishes; however, they constitute 32% of those imperiled. To aid in the conservation of burrowing crayfishes, we assessed the habitat of one primary burrower, Cambarus harti. Groundwater hydrology and chemistry were monitored from wells (<2m deep) installed near burrows and in similar areas without burrows at 4 Georgia locations for at least 1 year. Soils were characterized using 3 borings collected near wells (<10m). Groundwater was acidic and mostly hypoxic. Soils were 85.5% sand and 11.3% silt/clay but similar among wells with and without burrows. Water chemistry showed no consistent differences across burrow and non-burrow wells. However, groundwater levels near C. harti burrows were ~3 times closer to ground surface than areas without burrows. Thus, C. harti persisted in habitats with water near the ground surface (<50cm). While this species can tolerate fluctuating groundwater levels, prolonged depression of water table could jeopardize the viability of its populations.

Troy Keller (Primary Presenter/Author), Columbus State Unviersity, keller_troy@columbusstate.edu;


Jess Gilmer ( Co-Presenter/Co-Author), SynTerra Corp., jgilmer@synterracorp.com;


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15:15 - 15:30: / 305A THE USE OF ENVIRONMENTAL DNA FOR THE DETECTION OF A NARROWLY ENDEMIC CRAYFISH IN A HIGH-DISCHARGE, LOTIC ECOSYSTEM

6/06/2017  |   15:15 - 15:30   |  305A

THE USE OF ENVIRONMENTAL DNA FOR THE DETECTION OF A NARROWLY ENDEMIC CRAYFISH IN A HIGH-DISCHARGE, LOTIC ECOSYSTEM Narrowly endemic crayfishes often experience elevated risk for extinction given various biological, chemical, and physical threats facing their ecosystems. Orconectes eupunctus is a narrowly endemic crayfish inhabiting large streams in the Eleven Point River drainage in Arkansas and Missouri. We conducted a drainage-wide survey for O. eupunctus using conventional kick seine surveillance methods to assess the species’ distribution and potential abiotic habitat associations. Additionally, we employed environmental DNA (eDNA) surveillance methods to compliment species presence data obtained via conventional surveillance methods. Environmental DNA surveillance methods are potentially more sensitive to species presence given the ability of modern molecular analysis techniques to detect trace amounts of DNA from environmental samples, which may increase our ability to detect species in cases where conventional species surveillance methods do not. Orconectes eupunctus was detected at 38% of sites using conventional surveillance methods and showed habitat associations with mean substrate size, current velocity, and depth. Results from eDNA surveillance methods generally agreed with results from conventional surveillance methods, thus demonstrating that eDNA can reliably detect the presence of benthic organisms in high-discharge lotic ecosystems.

Christopher Rice (Primary Presenter/Author), University of Illinois, cjrice3@illinois.edu;


Eric Larson ( Co-Presenter/Co-Author), University of Illinois, erlarson@illinois.edu;


Chris Taylor ( Co-Presenter/Co-Author), Illinois Natural History Survey, cataylor@illinois.edu;


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15:30 - 15:45: / 305A WHAT DIFFERENCE DOES AN INVASIVE CRAYFISH MAKE? A SYNTHESIS OF THE FUNCTIONAL ROLES OF NATIVE AND NON-NATIVE CRAYFISHES IN ECOSYSTEMS

6/06/2017  |   15:30 - 15:45   |  305A

WHAT DIFFERENCE DOES AN INVASIVE CRAYFISH MAKE? A SYNTHESIS OF THE FUNCTIONAL ROLES OF NATIVE AND NON-NATIVE CRAYFISHES IN ECOSYSTEMS The introduction of a non-native crayfish species into a new region or habitat can have undesirable consequences, including negative effects on imperiled species. But do non-native crayfish function differently in ecosystems from the native crayfish they often displace? I review and synthesize findings of recent studies that have compared the effects of native and non-native crayfishes, including several recent meta-analyses of enclosure and mesocosm experiments, as well as field studies applying stable isotopes to compare the trophic niche of crayfishes and their food web interactions. Meta-analyses of small scale experiments have found little evidence of differences in effect sizes in ecosystem responses caused by native and non-native crayfishes, although these direct comparisons have been surprisingly rare. Stable isotope studies have found trophic niches of native and non-native crayfishes to range from highly similar to occasionally distinct. The few studies that have applied stable isotopes to characterize whole food web effects of non-native crayfish relative to native or uninvaded conditions have found some significant but relatively small effects of these invaders on their communities and ecosystems. I outline future directions needed to better understand ecosystem consequences of crayfish invasions.

Eric Larson (Primary Presenter/Author), University of Illinois, erlarson@illinois.edu;


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