The purpose of this study was to determine if habitat suitability criteria developed in the summer months for sma11mouth bass were transferable among streams representing different eco regions. Habitat suitability criteria were developed for depth, mean column velocity, cover and substrate for two size classes of sma1lmouth bass, 100-199mm and >200mm, in the North Anna River and Craig Creek, Virginia. Criteria that accurately describe habitat selection by a species or guild in a system different from where the criteria were developed are said to be transferable to that system. The transferability of suitability criteria between the North Anna River and Craig Creek, as well as depth and velocity criteria from Minnesota, the Huron River, Michigan and the Upper James River, Virginia, to the North Anna River and Craig Creek were tested using a 2x2 contingency table analysis. Depth criteria for the smaller sizes of sma1lmouth bass did not transfer well between regions; 4 of the 8 transferability tests (50%) failed. Depth criteria for larger sma1lmouth bass transferred to the North Anna River and Craig Creek in all cases. Velocity criteria developed for the smaller size classes did not transfer well among regions; only 3 of the 8 transferability tests were positive. Likewise, velocity criteria for larger sizes of smallmouth bass did not transfer well; only 1 of 8 tests were positive. General criteria were developed for depth and mean column velocity by averaging the suitability values reported from this and 3 other studies. General depth and velocity criteria transferred well to the North Anna River and Craig Creek for both the larger and smaller size classes of smallmouth bass; all depth tests were positive and 3 of 4 velocity tests were positive. The improved success of transferability warrants investigation of developing general criteria for smallmouth bass. Cover criteria for both size classes of smallmouth bass were transferable from the North Anna River to Craig Creek but not vice versa. Substrate heterogeneity criteria were not transferable between the North Anna River and Craig Creek for either size class of smallmouth bass. Criteria developed for the percentage of substrate particles >15cm (smallmouth bass >200mm only) were transferable from Craig Creek to the North Anna River but not vice versa. The transferability of habitat suitability criteria among regions was inconsistent and it is recommended that site-specific criteria be developed for each stream to which habitat assessments are applied. Additionally, nose velocities used were more consistent between the North Anna River and Craig Creek than were mean column velocities used. Hence, it is recommended that information on nose (focal point) velocities be incorporated into habitat studies to more accurately describe smallmouth bass velocity requirements. / Master of Science

There is little information on demographic trends of, or threats to the Wilson's Plover (Charadrius wilsonia), despite concerns that habitat degradation may be causing the species to decline. I studied Wilson's Plover demography, nest site selection, and physiological and behavioral responses to overflights at Cape Lookout National Seashore, North Carolina, where the National Park Service and U.S. Marine Corps recently lowered the altitude for overflights at tactical speeds. I monitored the responses of incubating Wilson's Plovers to overflights and other human activities and compared heart rate, incubation rate, and vigilance behaviors during time periods with and without these stimuli. I compared habitat use vs. availability at the island-scale, and nest placement relative to geomorphic features and vegetative cover, both on a local and island-wide scale. Wilson's Plovers increased vigilance during military rotary-wing and civilian fixed-wing overflights, but not during military fixed-wing overflights. Plovers were vigilant more and incubated less when researchers were present. Wilson's Plovers selected for interdune areas, flats and isolated dunelets on flats, and against beach and dunes. At the local scale, nests were more likely to be near dense vegetation than random points. Mayfield nest survival was 25%, and predation caused most of the nest failure. Daily nest survival was negatively correlated with nest age and initiation date. Nests with cameras and heart rate monitors had lower survival, and nests with predator exclosures had higher survival. The mean number of chicks fledged per pair was 0.78. / Master of Science

M. S.

Understanding the effects of large-scale disturbances and associated management actions on imperiled species can increase conservation value of future management. Piping plovers (Charadrius melodus) are federally threatened and endangered, disturbance-dependent shorebirds, nesting on broad, sparsely vegetated beaches, sandbars, and lakeshores. In October 2012, Hurricane Sandy storm surges cleared vegetation and opened old and new inlets through Fire Island and Westhampton Island, New York, creating plover habitat. Storm effects prompted an island-wide stabilization project, and certain sections of Fire Island were designed to create and/or improve plover habitat (hereafter, restoration areas) to mitigate possible habitat loss or degradation. Many plover populations range-wide appear to be habitat-limited, and we anticipated positive population growth following habitat creation. To help predict what might happen to the plover population following Hurricane Sandy, we evaluated the effects of habitat-creating events at several other locations in the range, evaluating the hypothesis that plover population sizes are habitat limited. We estimated the amount of habitat available before and after four significant storm and flooding events by classifying pre- and post-disturbance aerial imagery and evaluated the population changes that occurred after disturbance-related habitat alterations. Following these habitat creating events, nesting habitat increased 27%–950%, and, subsequently, these plover populations increased overall 72%–622% (increase of 8–217 pairs in 3 to 8 years after the disturbance, average 12–116% increase annually). The demographic changes likely were driven by some combination of productivity and immigration occurring simultaneously with regional increases. We then evaluated population and suitable habitat change on Fire Island and Westhampton Island following Hurricane Sandy. We developed an integrated population model to determine the primary contributors to population and assessed the effect of restoration areas on demographic processes during 2013–2018. We also recorded individual locations of adults and pre-fledge chicks to evaluate effects of post-Hurricane Sandy landscape features on resource selection of adults and chicks, and behavior and survival of plover broods. We evaluated whether breeding stage (pre-breeding, nesting, brooding, post-breeding), simple breeding stage (breeding, not-breeding), or instantaneous behavior class (parental, non-parental) best explained habitat selection during the 5-month plover breeding season. We also evaluated the effects of post-Hurricane Sandy landscape features on resource selection, behavior, and survival of plover broods during 2013–2019. We observed positive population growth in three of five years and overall growth through the study (λ ̅=1.12). Immigration and reproductive output were correlated with population growth (r = 0.93 and 0.74, respectively). Compared to the rest of the study area, restoration areas had higher chick survival but lower nest survival and breeding fidelity, and population growth (λ ̅=1.09) in restoration areas was similar. For adult plovers, behavior class best explained habitat selection. Compared to non-parental plovers, plovers engaged in parental behavior (incubating, brooding, and accompanying chicks, hereafter 'parental') selected areas closer to bay intertidal habitats and with more dry sand. Non-parental plovers avoided areas with more dry sand and did not select for or against bay intertidal habitats. Additionally, non-parental plovers avoided development more than parental plovers and avoided areas of lower elevation more than parental plovers. In each year, there was more suitable habitat for parental plovers than non-parental plovers. Plover broods selected for flatter sites with less vegetation but selected for sites closer to development as time since Hurricane Sandy increased. Chick foraging rates were highest in moist substrates and were negatively influenced by nesting plover density. Chick survival was negatively influenced by nesting plover density and was greater for earlier hatched broods. Further, chick survival was higher following an outbreak of sarcoptic mange in the local red fox (Vulpes vulpes) population. If human interventions were reduced or modified in such a way as to create, maintain, and improve habitat, plover populations likely would reach higher numbers, and the potential for achieving recovery goals would be increased. Future restoration areas projects could use Great Gun as a model, although design criteria could be improved to increase access to moist, flat, low energy foraging sites. Efforts to increase immigration of novel breeding adults into the system, primarily by habitat creation or maintenance, are likely to have the greatest local effect on population growth but may not improve regional population persistence if habitat creation is only local. Management to improve reproductive output is likely to have a positive effect on population growth if there is suitable habitat to support recruits and will improve regional population persistence by producing emigrants. When improving or creating plover habitat, managers should consider habitat needs both for plovers of all life stages. Habitat management should focus on maintaining vegetation-free sand and access to low-elevation foraging habitat. Allowing hurricanes such as Hurricane Sandy to alter the landscape naturally will create these landscape features. / Doctor of Philosophy / Piping plovers (Charadrius melodus) are federally threatened and endangered shorebirds that nest on sandy beaches, sandbars, and lakeshores. In October 2012, Hurricane Sandy created substantial habitat on Fire Island and Westhampton Island, New York, which could have acted as plover habitat. However, concerns about mainland safety from future storms prompted an island-wide project, building dunes planted with beach grass, to improve ability of Fire Island to protect the mainland. However, planted dunes had the potential to negatively affect newly created habitat, and certain sections of Fire Island were designed to create plover nesting habitat. Because of the habitat creation, we predicted that the population would increase. To illustrate that habitat creating events lead to plover population increases, we used freely available aerial imagery and identified all areas of dry and moist sand in study areas. We then used local plover monitoring data to relate habitat change to plover population change, and found that for several hurricanes and floods in the piping plover range, habitat increases led to population increase. We then evaluated population change on Fire Island and Westhampton Island, and found that the population increased 90% following Hurricane Sandy, and the increase was primarily due to new immigrant adults, and local reproductive success. The created restoration areas had similar reproductive output and population growth to the rest of the study area. To determine the areas on Fire Island and Westhampton Island that were adequate habitat for piping plover adults, we compared habitat used by plovers to what was available on the island and determined that habitat use differed between adults exhibiting parental behaviors and adults exhibiting all other behaviors. Non-parental plovers avoided dry sand. Both parental and non-parental plovers avoided development and high elevation sites. Overall, more sand was suitable for parental plovers than non-parental plovers. Because reproductive output also was influential to the population increase on Fire Island, we evaluated effects of landscape features on plover chick habitat, foraging, and survival. Plover chicks avoided vegetation, and selected flatter areas, but selected sites closer to development as time since Hurricane Sandy increased. Chicks spent more time foraging in moist substrates, and less time foraging when there were more plovers nesting in a management unit. Chick survival also was lower when more plovers were nesting in a management unit and was greater for earlier hatched broods. Further, chick survival was higher following a sharp decline in the local red fox (Vulpes vulpes) population. Overall, Hurricane Sandy was a positive force for this local plover population and local efforts to allow hurricane storm surges to modify the island in the future will improve long-term population persistence. Efforts to increase immigration of novel adults into Fire Island and Westhampton Island, primarily by habitat creation or maintenance, are likely to have the greatest local effect on positive population growth. Improving reproductive output is likely to have a positive effect on local and regional population growth, particularly by maintaining a low red fox population, if there is suitable habitat to support recruits. When improving or creating plover habitat, managers should consider habitat needs for plovers across the whole breeding season rather than just nesting. Habitat management should focus on maintaining vegetation-free sand, and access to low-elevation, flat foraging habitat. Habitat creation also may increase habitat amount and therefore local population growth.

Barrier islands are dynamic environments facing increasing vulnerability to climate changes, sea level rises, and anthropogenic activities. Hurricane Sandy (October 2012) modified the Atlantic coast of the United States. On Fire Island and Westhampton Island, New York, multiple overwashes and three breaches occurred. The U.S. Army Corps of Engineers filled two breaches, increased dune elevation and stabilized dunes by planting American beachgrass (Ammophila breviligulata). They built two restoration areas to mitigate the impact of an island stabilization project to federally listed breeding piping plovers (Charadrius melodus). The goal of this thesis was to quantify habitat changes after Hurricane Sandy, and assess habitat use of piping plovers specifically in human-created restoration areas. We created land cover maps using an object-based classification method (overall accuracy 85%), and field-collected data from four post-hurricane habitat types. Vegetation cover increased across all habitat types, especially in manipulated (30.1% increase) and natural overwashes (37.9% increase), while dry sand for nesting declined by 8%. Vegetation density indices were higher in natural overwashes than planted engineered dunes, likely a reflection of plant age and establishment. We monitored 83 nests (67 pairs) of piping plovers from 2015–2017. Restoration areas were successful in attracting breeding piping plovers, although pair densities were lowest in this habitat in 2016, and in 2017 plovers selected against the restoration areas (�2 = 29.47, df = 3, p<0.0001). There was no effect of habitat type on reproductive parameters. We suggest vegetation removal may be necessary to maintain early successional habitats for piping plover management. / Master of Science / Barrier islands are thin strips of land, which generally lie parallel to the mainland. They are dynamic environments subject to change from weather conditions and ocean currents. They are vulnerable to future climate changes, sea level rise, and increased human activity. Hurricane Sandy, October 2012, caused major landscape changes to the Atlantic coast. On two barrier islands, Fire Island and Westhampton Island, south of Long Island, the U.S. Army Corps of Engineers (USACE) further modified the post-hurricane habitats. They created two restoration sites designed to offset the impact of an island stabilization project to a federally protected breeding shorebird, the piping plover. Piping plovers nest on unvegetated or sparsely vegetated sand. We created land cover maps from aerial images and collected field data to describe habitat changes after Hurricane Sandy (2013, 2015–2017) in four habitat types creating during or after the hurricane. The vegetation cover and density increased across these four habitats, but especially in the manipulated overwashes and natural overwashes. This is likely due to the age of the plants in each habitat type. As vegetation grew back, areas of sand in each habitat type declined. Human-created restoration sites were used by plovers but in 2017 plovers used them less than expected. We monitored piping plover nests and chicks (April to August 2015–2017), and there were no differences in these measurements among habitat types. The findings from this thesis will assist in piping plover conservation on Fire Island and Westhampton Island.

During the winter 1988-89, diurnal and nocturnal habitat use by juvenile female canvasbacks wintering on the upper Chesapeake Bay was determined. Radio-implanted canvasbacks used shallow water (0-2 m) areas near artificial feeding sites during the day, and deeper water (2-6 m) that had an abundant (> 200/m²) population of small (< 25 mm) Macoma balthica at night. Because of poorer Macoma populations on the east side of the Bay, canvasbacks there may feed more during the day and are in lower Macoma densities at night than west shore canvasbacks. Management of Chesapeake Bay canvasback populations should focus on providing natural foods and rest areas. / Master of Science

Blackburnian Warblers (Dendroica fusca) were observed in their wintering grounds in a High Andean native secondary forest in Colombia between September 1993 and May 1994. The main objective of the study was to determine the relationships between the Blackburnian Warblers and the habitats where they were found. Size and composition of the mixed-species flocks joined by Blackburnian Warblers were also compared to habitat features. Habitat variables were measured in circular plots centered where a Blackburnian Warbler was first seen. The same set of variables was measured in randomly located paired plots to compare the two sets. The results obtained in Colombia (wintering grounds) were compared to similar data available from North America (breeding grounds). Ninety-six mixed-species flocks with Blackburnian Warblers were detected. Some of the habitat variables measured differed between plots used by the birds and the random plots. Density of trees in all dbh (diameter at breast height) categories, density of snags and density of native trees and shrubs were higher at the bird-centered plots. Percentage vegetation density (understory foliage volume) from O-1m, 1-2m and 2-3m were lower at bird-centered plots. There was no significant difference for maximum and mean canopy height between bird-centered and randomly selected paired plots. At Los Amarillos, Blackburnian Warblers avoided Eucalyptus spp. trees. They preferred the higher part of the trees and trees in the middle and high abh classes. They avoided the smallest dbh size class (3-8cm dbh). Comparisons were made between the data from Los Amarillos and data available from northern central Minnesota (Collins et al. 1982). Percent ground cover, densities of trees 15.1-23, 23.1-38 and 38.1-53 cm dbh and total density of trees were significantly higher in Minnesota. Trees 7.5- 15, 53.1-68 and > 68.1 cm dbh were higher in Los Amarillos. Percent canopy cover was not different between the two Sites. Blackburnian Warblers selected for closed canopy cover (about 75%) and large trees in each individual site. They selected larger trees in Minnesota. This selection may be related to nesting requirements of the species. / Master of Science

I radiotracked 31 bog turtles (<i>Clemmys muhlenbergii</i>) from May 1995 to December 1996 at 4 study areas in southwestern Virginia. Radio location data were used to provide measures of annual activity, spatial distributions of animals, and habitat selection. The techniques I used in this study were as follows: distance measurements between consecutive locations, home range estimators (Minimum Convex Polygon [MCP] and cluster analysis), compositional analysis of habitat selection, and measurement of microhabitat variables. Results suggest a random pattern of movement by bog turtles within habitats. Average net movements recorded between consecutive locations (separated by < 7 days) during 1995 and 1996 measured 15 m and 20 m for females and 14 m and 23 m for males respectively. Eighty-six percent of all net movements (n = 824) were less than 30 m, whereas only 2% were greater than 100 m. In 1996, average home range sizes (95% MCP, 95% cluster) were 0.47 ha and 0.17 ha for females and were 0.57 ha and 0.13 ha for males. Bog turtles selected wet meadow areas and bulrush (<i>Scirpus</i> spp.) patches more than expected randomly and avoided dry meadow areas and streams. Turtles were located more frequently in mud (x = 24.3 cm) and water (x = 5.2 cm) than expected by random selection (P < 0.001). I found no differences between sexes in movement, home range, or habitat selection by bog turtles. Bog turtles select specialized habitat types and microhabitats within wetlands. Large-scale movements are infrequent and the risk of site isolation may be high if wetland habitat loss continues at historic rates. Future management should protect spatially-close sites which contain multiple habitat types, soft substrate, and pockets of water. / Master of Science

Prairie rivers of the Great Plains, USA, provide important habitat for the federally threatened piping plover (“plover”, Charadrius melodus). Plovers nest on open to sparsely vegetated river sandbars, and their demographic rates are closely linked to habitat availability and quality, as well as river flow. The Niobrara River in northern Nebraska has supported 22–41% of the state’s plovers since species listing in 1986, but the population and habitat are relatively understudied, and both have declined since 2010. The objectives of this study were to understand plover demography, habitat, and the role of the Niobrara in the regional plover population. Periods of high river flow promote creation and maintenance of suitable sandbar nesting habitat, but increased river flow during the plover breeding season can decrease nest and chick survival. We estimated the effect of daily peak river flow on survival rates of 115 nests and 66 chicks on the Niobrara River, 2010–2016, using logistic exposure and Cormack-Jolly-Seber models, respectively. We monitored 1,874 banded hatch-year and adult birds across the regional population (Niobrara River, Lewis and Clark Lake, Gavins Point Reach segment of the Missouri River), and used multi-state mark-recapture models to estimate survival and inter-annual dispersal probabilities among sites relative to habitat availability. We developed land cover datasets from high-resolution aerial imagery to quantify suitable habitat and compare the relative effects of habitat characteristics on nest-site selection and nest success for a subset of years (2010, 2012, 2014, and 2016) using logistic regression models. We included data from a sympatric nester with similar nesting habitat needs, the interior least tern (“tern”, Sternula antillarum athalassos), to improve precision of our models. We compared 63 plover and 92 tern nests to 292 random unused points, and 73 successful (hatched ≥1 egg) to 79 failed nests. Low nest and chick survival and high emigration from the Niobrara appear to be important factors contributing to population decline. Daily nest and chick survival were negatively related to river flow. Nest-site selection was based primarily on distance to the river bank (i.e., the nearest potential source of predators), yet flooding (eggs submerged or washed out of the nest bowl during increased river flow) caused at least as many nest failures as predation. Nests predominantly were surrounded by dry sand habitat, indicating some degree of flood avoidance, but were no farther from water than random, and drier nest sites were no less likely to fail. Dispersal occurred throughout the regional population, but plovers were more likely to leave the Niobrara than to enter it. Expansive flood-created sandbars on the Missouri River, concurrent with a trend towards more vegetated and saturated habitat on the Niobrara, may have drawn birds from the Niobrara population, especially those that dispersed to the Niobrara during sustained Missouri River flooding 2010–2011. The outsized negative effect of flooding on nest success, the lack of protection afforded by dry sand nest sites, and selection for nesting habitat based more strongly on predator avoidance than flood avoidance suggest that plovers may have face more frequent and intense levels of breeding season flooding than is typical. Identifying and promoting the processes that contribute to creation and maintenance of high-elevation sandbars on the Niobrara is an important next step towards effective management of nesting birds. / Master of Science / Prairie rivers of the Great Plains, USA, provide important habitat for a federally threatened shorebird, the piping plover (“plover”, Charadrius melodus). During their breeding season (April–August), plovers nest and raise chicks on open to sparsely vegetated areas of river sandbars, and their survival and reproductive success are closely tied to amount and quality of sandbar habitat. The number of plovers on the Niobrara River in northeast Nebraska has declined since 2010, and in this study our objectives were to monitor nests, chicks, and adult birds to document plover survival, movement among neighboring sites, reproductive success, and habitat changes on the Niobrara from 2010–2016. Because plovers nest on the sand, they can lose nests and chicks when river flow increases and washes over sandbars (“flooding”). We found that nest and chick survival sharply decreased when river flow was high. Plovers chose nest sites in dry sand areas, which are typically the tallest part of a sandbar and most protected from flooding, but these nests were no more likely to hatch than those in areas with wetter (lower elevation) sand. Plovers primarily chose nest sites far from the river bank, which was the nearest potential source of predators, yet flooding caused at least as many nest failures as predation. Plovers moved between the Niobrara and nearby Missouri River, but overall were much more likely to leave the Niobrara than to enter it. Expansive sandbar creation on the Missouri River, concurrent with a trend towards lower-quality (more vegetated and saturated) habitat on the Niobrara, may have drawn birds from the Niobrara population, especially those displaced from the Missouri during sustained flooding 2010–2011. Movement to the Missouri River and low nest and chick survival due to flooding contributed to population decline on the Niobrara. The outsized effect of flooding on nest success, the lack of protection afforded by dry sand nest sites, and selection for nesting habitat based more strongly on predator avoidance than flood avoidance suggests that plovers face more frequent and intense levels of breeding season flooding than is typical. Identifying and promoting the processes that contribute to creation and maintenance of high-elevation sandbars on the Niobrara is an important next step towards effective management of nesting birds.

During the spring and early summer of 1978, boundaries were determined for 19 yellow-breasted chat (<i>Icteria virens</i>) territories in southwestern Virginia. The gross structural characteristics of the vegetation found within these areas were analyzed. Each vegetation variable was regressed against territory size and against a measure of chat density. It was assumed that both smaller territories and territories having a greater number of territories surrounding them contained better quality habitat. Chats appear to choose their habitat on the basis of the total brushiness present. of several different components. This value may result from the summation In this study, bramble (<i>Rubus</i> spp.) cover and total shrub cover were the two major components involved. The vegetation contributing to the total brushiness value should minimally provide about 25% cover and average about 0.75 min height. Increased greenbrier (<i>Smilax</i> spp.) cover is associated with better quality chat habitat. Presumably, it is indicative of the types of vegetation, such as thickets and open woods, which are characteristic of chat habitats. However, the measure of greenbrier cover seems limited in its ability to distinguish preferred chat habitat. Chat territories may include wooded areas provided there is a fairly dense growth of vegetation below about 1.5 m. Generally, this situation would occur only in a woods with a reasonably open canopy. If only an edge of a woods bordering a brushy field is involved, side-lighting may be sufficient for the growth of ground-level vegetation, even if under fairly dense overstory vegetation. / M. S.