AUTHORS: Derek Whipkey, Cooperative Wildlife Research Lab, Southern Illinois University; Charlotte Narr, Department of Zoology, Southern Illinois University; Brent Pease, School of Forestry and Horticulture, Southern Illinois University; Guillaume Bastille-Rousseau, Cooperative Wildlife Research Lab, Southern Illinois University
ABSTRACT: Semi-aquatic mammals play important roles in aquatic ecosystems, particularly in the transfer of nutrients between aquatic and terrestrial environments. However, detecting and estimating the occurrence of these species can be difficult due to their elusive nature. Additionally, most occupancy studies have focused on a single type of waterbody (e.g. lentic or lotic systems), limiting a broader understanding of factors impacting these species distribution. To estimate occupancy of semi-aquatic mammals, we surveyed 67 sites across four counties in southern Illinois from March – May 2023 for American beaver (Castor canadensis), muskrat (Ondatra zibethicus), river otter (Lontra canadensis), and American mink (Neovison vison). Sites were distributed evenly between waterbody type and size. Given the elusive nature of these species, we combined two detection methods, sign surveys and camera traps, to increase detection. We applied a Bayesian multi-method occupancy model that incorporates both detection methods to estimate a single occupancy probability for each target species. To evaluate the relative importance of aquatic and terrestrial factors on occupancy, we built candidate models of aquatic and terrestrial covariates separately to identify the top model of each category. Aquatic covariates were consistently more important in predicting occupancy for all species. However, a combined additive model of the top aquatic and terrestrial models provided the best overall predictions. Beaver, otter, and mink occupancy showed positive associations with large waterbodies, while muskrat occupancy was positively linked to lotic systems. Additionally, muskrat and mink occupancy were positively related to increasing distance from roads. Our results suggest that while aquatic structure is more influential for predicting semi-aquatic mammal occupancy, considering both aquatic and terrestrial factors yields the most accurate results. All four semi-aquatic mammal species we studied were impacted by aquatic type, highlighting the importance of considering both waterbody types to better understand their distribution.
AUTHORS: Abigail G Blake-Bradshaw, Forbes Biological Station; Therin M Bradshaw, Forbes Biological Station; Andrew D Gilbert, Forbes Biological Station; Joshua M Osborn, Forbes Biological Station; Elizabeth A Beilke, Forbes Biological Station; Chelsea S Kross, US Fish & Wildlife Service; Auriel MV Fournier, Forbes Biological Station
ABSTRACT: Hunting pressure and associated disturbance influences many aspects of wildlife behavior. Disturbance by hunters influences the timing of relocation movements of waterfowl and could drive departures from stopover locations during autumn. Additionally, environmental conditions, including short-term changes in weather or habitat availability, may necessitate shifts in activity patterns, alter departure decisions, or impact individual susceptibility to harvest. Thus, wildlife professionals are interested in understanding what drives autumn-winter movements and migration events of waterfowl; therefore, we evaluated the extent to which hunting pressure and environmental conditions influenced daily flights and departure from an autumn stopover location. Our study took place in of the La Grange Reach of the Illinois River Valley, IL, USA. To evaluate the influence of “hunting pressure” on waterfowl behavior and departure from a stopover location, we placed 20 Autonomous Recording Units (ARUs) across our study area to quantify daily shotgun volleys. We then captured 38 mallards (Anas platyrhynchos) and 26 green-winged teal (A. crecca; hereafter teal) at Chautauqua National Wildlife Refuge, IL, USA. We deployed GPS-GSM transmitters on both age (i.e., juveniles and adults) and sex classes (i.e., males and females) and tracked both species during autumn and winter 2022–2024. We quantified the number of daily local-scale flights and related it to local environmental conditions and hunting pressure as indexed by ARUs. The median number of local-scale flights was 3 (range: 0–18) and was similar between species. Additionally, we identified the day individuals departed the Illinois River Valley stopover area by quantifying when they passed 40°N southwards, which marked the southern extent of our study area. In total, 24 teal and 8 mallards departed the study area, and as hunting pressure increased, teal were more likely to depart southwards. Preliminary results indicate mallards and teal responded to environmental conditions and hunting pressure disparately.
AUTHORS: Jeffrey Edwards, Missouri Cooperative Fish & Wildlife Research Unit, School of Natural Resources, University of Missouri; Dr. Lisa Webb, U.S. Geological Survey, Missouri Cooperative Fish & Wildlife Research Unit; Dr. Drew Fowler, U.S. Geological Survey, Louisiana Cooperative Fish & Wildlife Research Unit; Paul Link, Louisiana Department of Wildlife & Fisheries; Dr. Chris Nicolai, Delta Waterfowl
ABSTRACT: Migration is an important life history strategy that many waterbirds employ to exploit seasonally available resources and maximize fitness. However, migratory events are energetically demanding, and waterbirds use stopover sites during migration to rebuild energetic reserves. During spring migration, habitat quality at available stopover sites has the potential to exert cross-seasonal effects on breeding season population demographics. Wetland availability during the migratory period can be temporally dynamic within and across years as well as spatially variable throughout the migration corridor. Only recently has quantifying the spatial and temporal extent of available wetlands at broad scales become possible with remote sensing technologies. However, little is known about how temporally and spatially dynamic wetland availability may influence waterfowl resource selection during the non-breeding season. In this study, we collected movement data from 350 blue-winged teal (Spatula discors) marked with GPS-GSM transmitters to assess the effects of inundated wetland availability on blue-winged teal resource selection during the autumn and spring migrations (2019 – 2024). We used the Dynamic World dataset to quantify temporally and spatially dynamic inundated wetlands and intersected this data layer with landcover types from the National Land Cover Database. Combining these data sources, we will use an integrated step selection function to evaluate how blue-winged teal resource selection varies with inundated wetland availability at two-week intervals. The spatial extent of each two-week interval will be based on sample wide kernel density estimates of use. Results from this study can help inform wetland conservation and management practices for early autumn and late spring migrating waterbirds such as blue-winged teal. Specifically, these results can inform how early autumn wetland inundation and maintaining water into spring may support waterbirds whose life history strategies include this migration phenology.
AUTHORS: Presenter: Ryan McGinty (SUNY Brockport, Brockport, NY)
Co-Authors: Kristen Malone (SUNY Brockport, Brockport, NY), Lisa Webb (USGS, Columbia, MO), Arianne Messerman (Missouri Department of Conservation, Columbia, MO), Janet Haslerig (Missouri Department of Conservation, Jefferson City, MO), and Doreen Mengel (University of Missouri, Columbia, MO)
ABSTRACT: Several species of secretive Marsh are facing population declines in the U.S., including the King Rail which is listed as endangered in several U.S. states. Wetland management practices commonly used on public properties in Missouri and elsewhere have been developed to produce vegetation and water conditions that benefit waterfowl. However, the effects of waterfowl-focused wetland management on secretive marsh birds are not well known. The purpose of this project is to determine the current distribution of King Rail in Missouri and to evaluate the effects of habitat characteristics and wetland management practices on breeding secretive marsh birds. In 2023, we conducted call-playback surveys at 84 survey points across 14 publicly managed properties in Missouri. We detected King Rail at 4 survey points across 3 wetland pools. Two of these wetland pools were permanently inundated with water and the other as drawn down in the month of May. Due to few detections of King Rail, we used Least Bittern as a surrogate in occupancy analyses. We detected Least Bittern at 18 survey points. Their site occupancy was positively associated with percent cover of both tall emergent vegetation (β = 4.616, 85% CI = 1.901 – 7.931), percent cover of water (3.696, 1.596 – 6.496), and water depth (2.329, 0.449 – 4.720). Points with greater interspersion were more likely to be occupied by Least Bittern (4.496, 0.852 – 10.088). Wetland pools that were drawn down annually were less likely to be occupied by Least Bittern than sites that were permanently inundated with water (-7.117, -13.886 – -1.551). Least Bittern occupancy was also positively associated with a later initiation of spring drawdowns (6.555, 2.457 – 12.645). Our results represent an important first step for moving forward King Rail conservation in Missouri and for testing the assumption that waterfowl habitat management produces habitat for secretive marsh birds.
AUTHORS: Josh Williams, Missouri Cooperative Fish and Wildlife Research Unit, School of Natural Resources, University of Missouri, Columbia, MO 65211, USA; Lisa Webb, U.S. Geological Survey, Missouri Cooperative Fish and Wildlife Research Unit, School of Natural Resources, University of Missouri, Columbia, MO 65211, USA; Jonathan Spurgeon, U.S. Geological Survey, Nebraska Cooperative Fish and Wildlife Research Unit, School of Natural Resources, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
ABSTRACT: During the 20th century, extensive flood control infrastructure was built along many US rivers, separating mainstem river channels from floodplains and altering floodplain wetland structure and function. Wetland restoration often occurs in locations where levees have disconnected the floodplain from the mainstem river channel. Disconnected wetlands can experience reduced nutrient exchange, habitat heterogeneity, biodiversity, and hazard mitigation compared to wetlands in connected floodplains. Understanding the effects of river-floodplain connectivity on wetland restoration efforts has been limited—in part—by brief time periods between restoration and evaluation. The Agricultural Conservation Easement Program – Wetland Reserve Easements (ACEP-WRE) program, established in 1990, is a voluntary program that provides landowners with technical assistance and financial incentives to restore marginal farmland to historic wetland conditions. Our objective is to compare abiotic and biotic metrics in ACEP-WRE wetlands along a gradient of restoration age (6 to 29 years) and degree of connectivity between the Missouri River and the adjacent floodplain. Hydrological connectivity was categorized based on wetland proximity to an adjacent levee system (landward or riverward) and quantified using continuous temperature logging units, level of local mainstem channel incision, and historical river stage data. At each ACEP-WRE site (riverward sites n = 26, landward sites n = 24), water, soil, and algae samples were collected along with surveys of vegetation, macroinvertebrate, fish, amphibian, and bird assemblages. We compare metrics for riverward and landward sites with six reference and six control sites to elucidate whether river-floodplain connectivity affects the time needed to achieve ACEP-WRE restoration goals.
