Small, fragmented populations are at greater risk of extirpation due to reduced genetic diversity from inbreeding and genetic drift. These processes ultimately decrease individual fitness and reduce the ability of a population to adapt. Hill's thistle (Cirsium hillii) is classified as a threatened species throughout much of its range, primarily due to the destruction and fragmentation of its habitat. This study addresses the impact of population size and isolation on the genetic diversity of Hill's thistle. We used microsatellite markers to genotype plants collected from the Lower Peninsula of Michigan in 2001, and from the Lower Peninsula and Drummond Island in 2012, in order to assess genetic differentiation across time and space, as well as to investigate rates of inbreeding in isolated and nonisolated populations. Genetic differentiation between the sample sites in the mainland population of Hill's thistle increased significantly between 2001 and 2012, indicative of increased fragmentation and isolation of the sample sites. However, the 2012 population exhibited lower inbreeding and no difference in heterozygosity or allelic diversity compared to 2001, suggesting the population is stable, or growing, in spite of isolation. Conversely, the population on Drummond Island displayed higher levels of inbreeding and lower number of effective alleles and heterozygosity compared to the mainland, typical of a small, isolated population. Our results indicate that the mainland population of Hill's thistle is persisting but should continue to be monitored demographically due to ongoing habitat loss.

Overcompensation to herbivory is prevalent among plant species. However, we do not yet fully understand why plant species vary in their compensatory abilities. It is highly likely that overcompensation is determined by the ability of plants to elevate photosynthesis in response to herbivory, which is dictated by evolutionary exposure to grazing. Here, we tested the hypothesis that photosynthetic overcompensation should be predictable based on plant life form by simulating herbivore damage on four plant species: two common range grasses with long evolutionary exposure to grazing (Andropogon gerardii, Bouteloua curtipendula) and two common understory forbs that are resistant to, and therefore experience little, grazing (Alliaria petiolata, Symplocarpus foetidus). We measured leaf-level gas exchange in a high-resolution time series that extended throughout the growing season. We found no evidence of photosynthetic compensation for three of the four plant species. Interestingly, only A. petiolata, a highly invasive species, demonstrated increased photosynthesis and stomatal conductance following clipping. Further, the effects were short-lived, as both photosynthesis and stomatal conductance returned to baseline levels within 24 h. Our results suggest that elevated photosynthesis to herbivory might not be a general mechanism by which plants either resist or tolerate herbivory.

The ability of organisms to survive ingestion and digestion by their predators, or endozoochory, is a fascinating ecological phenomenon that can facilitate predator-mediated dispersal of prey and alter interaction strengths within ecological networks. However, the role of endozoochory in the context of invasive species is considered less often. Throughout the United States, Silver Carp (Hypophthalmichthys molitrix) are prolific invaders that often alter food web structure of recipient ecosystems through the consumption of basal resources. Despite the biogeochemical and food web effects of Silver Carp, there is limited understanding of plankton prey survival after Silver Carp consumption and digestion, and even less known about the ecological effects of selective diets and potential survival. In this study, we quantify hindgut contents of Silver Carp collected from Kentucky Lake, Kentucky, Tennessee River Valley, United States. We found the majority (83%) of phytoplankters within hindguts of Silver Carp showed little digestion prior to egestion. Our study suggests digestion limitations of Silver Carp may have important ecological implications for invaded environments. These results may be applicable in understanding how this rapidly spreading invasive fish can influence food web dynamics and biogeochemical cycles pertinent to toxic algal blooms within recently invaded ecosystems, and forecasting invasion in the near future.

Immature raptors often travel long distances and move nomadically from the time they leave their natal area to the time they are recruited into the breeding population. Emphasis on identifying the nesting and winter habitat of Bald Eagles (Haliaeetus leucocephalus) has overshadowed the need to understand the habitat and spatial use of young eagles prior to reaching maturity. We used satellite telemetry to track the movements of immature Bald Eagles hatched in western Kentucky during 2010–2016. We analyzed movement data to identify high-use areas for eagles in their first and second years during warm and cool periods. Five out of seven eagles migrated north to the Great Lakes region during their first year. Using Brownian Bridge Movement Modelling, we identified 47 noncontiguous high-use areas during the warm period and 67 during the cool period. Public lands comprised 17% of warm period high-use areas and 43% of cool period high-use areas. High-use areas were located in Illinois, Indiana, Kentucky, Arkansas and Tennessee, and were often near federally-owned dams, rivers with sandbars, or areas with abundant waterfowl. Our small sample of tracked eagles correctly identified known Bald Eagle concentration areas within the study area; thus, we infer that previously unrecognized high-use areas identified by this study are likely to be concentration areas important to the larger population. We further suggest remote sensing data, even in limited datasets, as an efficient way to identify Bald Eagle concentration areas.

Bird-window collisions (BWCs) constitute a significant source of mortality for both resident and migratory birds. Because windows reflect surrounding landscape components, such as vegetation or sky, birds do not always perceive glass as a barrier. Here we demonstrate a novel technique to classify and quantify reflections in windows on the Radford University campus in southwest Virginia, U.S.A. We deployed a consumer-grade Unmanned Aerial Vehicle, i.e., drone, to photograph 14 contiguous or near-contiguous window columns across five campus buildings in August 2020. For each study aspect, the drone (equipped with an RGB camera) captured images at ca. 5 m altitudinal increments from the ground floor to the roof of each building (three to six images/vertical column). We then manually classified each image in ImageJ to calculate approximate proportions of reflected: (1) vegetation, (2) sky, (3) and artificial structures or impervious surfaces, plus (4) nonreflective glass. We used a generalized linear model to determine how proportional reflections of vegetation, sky, buildings, and nonreflective glass varied across vertical increments. We found the proportion of sky significantly decreased with increasing photo heights, whereas proportion of nonreflective glass significantly increased with increasing heights. This supports previous findings that because birds are drawn to sky reflections, they may collide at relatively lower positions on buildings. Inconsistency in landscape design and building positioning on the campus precluded trends in vegetative or building reflections by height. Our pilot study demonstrates the applicability of a consumer-grade drone for investigating visual characteristics of reflections that influence BWCs from variable observation angles. We suggest the expanded use of drone images as a straightforward technique to measure changes in reflection characteristics from varying degrees of observation. They are a novel method in developing a BWC risk assessment as well as potential mitigation strategies in a suburban or campus environment with buildings of intermediate heights.

I describe the phenology of territorial Greater Sandhill Cranes (Grus canadensis tabida) from a long-term (20+ y) marked population near Briggsville, Wisconsin. Territorial adults typically arrived in mid-March (average = 27 Mar., median = 25 Mar.) and egg-laying commenced a median date of 2 wk post-arrival. Chicks typically hatched in mid-May (average and median = 12 May). Renesting occurred from 3-14 d after the first clutch failed and renests hatched from late May to early July (95% CI: 23 May–8 Jul.). Known territorial birds began congregating in mid-Sept, and fall migration typically occurred in late Nov. Territory use by adults occurred at all stages of the annual cycle and may be a way to ensure reclamation of the territory in subsequent years.

Myotis bats have experienced significant population losses due to white-nose syndrome (WNS) throughout large portions of their distributions in eastern North America. As closed-space foragers, these species comprise an important feeding guild within eastern forests. An understanding of where summer populations remain and how their ecology has changed following impact from WNS is needed to assess fully the recovery potential of Myotis bats. We used acoustic sampling, capture surveys, radiotelemetry and roost surveys from 2015 to 2018 to evaluate the status of northern long-eared bat (Myotis septentrionalis) in an eastern Kentucky forest following region-wide impacts from WNS to this species. Acoustic activity of Myotis remained unchanged over the 4 y of sampling, with activity of these bats greatest in mid- to late July. Northern long-eared bats represented 97% of the Myotis captured, indicating activity levels likely reflected patterns for this species. We located 18 roost trees of northern long-eared bats in five tree species, including both live and dead trees. All roost trees were on upper slopes within 100 m of ridge top roads. Maximum exit counts, 24 and 21, at two roosts occurred in late May and early June, suggesting these dates represented the summer maternity period of northern long-eared bats in this forest. Our results demonstrated that post-WNS populations of northern long-eared bats on Robinson Forest formed small colonies, day-roosted in trees near roads on forested ridge tops, were reproductively active, and maintained steady levels of activity across the 4 y of sampling. These data suggest that local populations of northern long-eared bats are surviving WNS and continue to persist during summer months in forests of the Appalachian Mountain region. We hypothesize presence of ridge top roads, often associated with forest logging operations, may be important habitat elements for increasing availability of preferred roosting habitat for summer populations of northern long-eared bats in actively managed forests.

Forest bats, including evening bats (Nycticeius humeralis), sometimes roost in manmade structures, such as barns and bridges, but here we report the first observations of evening bats using bird nest boxes for roosting on multiple occasions between 2012 and 2019, a few kilometers north of Jonesboro, Arkansas. Most encounters were in August, when the nesting season is almost finished. We discuss timing and factors that may explain use of bird nest boxes for roosting by bats.

The visual capabilities of prey species such as white-tailed deer (Odocoileus virginianus) must be specialized to enhance predator detection and traverse a complex physical environment. Although aspects of the visual system of deer have been investigated, there has been no evaluation of the species' spatial resolution abilities. We used a behavioral assay to estimate visual acuity of three adult female deer using operant conditioning techniques. We estimated the spatial resolution is between four and six cycles/degree. Our results suggest the white-tailed deer eye allows relatively low spatial resolution, consistent with prior studies that reported high temporal resolution. The combination of low spatial resolution and high temporal resolution allows for efficient detection of movement and enhanced capability to transverse a complex environment.

Wolf predation of beaver is common in boreal ecosystems, but predation events are thought to be rare in winter. We describe the encounter of a recent wolf predation event of a beaver during conditions of ice cover. The beaver had a broken upper incisor, which may have contributed to it foraging on land during the winter. While it is common for injured animals to have increased vulnerability to predation, injuries can also influence foraging decisions that may indirectly increase vulnerability to predation.

We assessed a large-scale fish die off event resultant of prolonged anoxic conditions on Grand Lake St. Marys in west central Ohio, U.S., during the summer of 2020, and used this as the basis for comparing long-term species diversity in the lake over the past century. Fish collections were made along a series of shoreline and open water transects, totaling approximately 1.5% of the entire 5220 ha lake area (majority of surveys were shoreline), wherein we identified a total of 12,351 fish comprised of 25 taxa. We used this die off event, combined with recent near shore seine survey data, as an opportunity to assess the modern assemblage structure and to serve as a reference point to prior collected data over the past century. Combining these recent data with historical records, we found that although 57 species have been recorded from the lake dating back to the mid-1800s, only 30 taxa are known to inhabit the lake today. Some of the lost taxa predictably include more intolerant species from the Darter (Percidae), Minnow (Cyprinidae), and Sucker (Catostomidae) families; however, there were also instances of increases in taxa resulting from both state stocking efforts (e.g. Flathead Catfish, Pylodictis olivaris) and natural distribution expansions (e.g. Freshwater Drum, Aplodinotus grunniens). Overall, we attribute the changes to the fish assemblage as negative, given no intolerant taxa currently inhabit the lake. We attribute these long-term changes to watershed wide destruction of natural forest, wetland, and prairie habitats that once typified the region.