Habitat Ecology & Management I

Contributed Oral

There’s Snow(Shoe) Place Like Home: Integrating Field Measurements and Remotely Sensed Data to Assess and Model Snowshoe Hare Habitat
Courtney King, Rebecca Stern, Matthew Vasquez, Ian Breckheimer, Jessica Young

The Southern Rocky Mountains are at the southern range of snowshoe hares (Lepus americanus) and their iconic predator, the Canada lynx (Lynx canadensis). In this region recreational uses, backcountry roads and trails, and other human developments have been identified as risk factors affecting lynx productivity through altering the snowshoe hare prey base. Beginning in 2013, Crested Butte Mountain Resort in western Colorado began proposals, and was approved in 2019 to construct ski trails and infrastructure in an undeveloped section of the Gunnison National Forest that currently supports snowshoe hare. In continuation of a 2016 pilot study, we carried out fecal pellet counts in the summer-fall of 2020 to assess whether this area contains adequate hare density (~0.5 hares/hectare) to support the imperiled Canada lynx. Pellet counts were significantly higher at a site dominated by old-growth spruce-fir forest, which has been cited as an important determinant of snowshoe hare and Canada lynx presence. Mean and median pellets counted varied by year; nonetheless, in neither year nor study site did values reach the threshold of 0.5 hares/hectare. We also estimated dense horizontal cover, considered an important component of winter hare habitat, as a rough assessment of habitat quality. Alongside this data, we utilized forest structural variables derived from satellite and LiDAR imagery to develop candidate models for predicting snowshoe hare population density. Our aim was to determine whether remotely sensed data could serve as a supplement or alternative to the traditional, resource-intensive field methods for assessing snowshoe hare population density and habitat quality for lynx management purposes. We conclude that open-access, remotely sensed data is valuable for land managers, but may not yet be collected at the scales suitable to assess habitat for species that rely on both stand-level variables (i.e., forest type) and fine-scale forest structural variables including dense horizontal cover.

Long-Term Passive and Active Management, Data Collection and Trends, of a High Desert Riparian and Upland Preserve in Southeastern Mohave County, Arizona
Julie Alpert

The Willow Creek Riparian Preserve (Preserve) is a 130-acre site located 30 miles east of Kingman, Arizona.  The Preserve was formally established in 2007 with the purchase of 10-acres and agreement with the eastern adjoining private landowner to add approximately 20-acres of upland and riparian habitat upstream.  The Preserve location was unfenced and wholly accessible by livestock, off-road vehicle use, and hunting.  In October of 2008 the Preserve was fenced with volunteer efforts from the local Rotary Club and Boy Scout Troop 66.  Additional financial assistance came through a large discount in the cost of fencing materials from Kingman Ace Hardware.  A total of 0.5-linear mile of new fencing was installed along the south and west sides and connected to existing Arizona State Lands cattle allotment fencing.  Baseline and on-going studies and data collection have occurred since 2004.  These have included small mammal live trapping; chiropteran surveys with the use of Anabat; migratory, breeding, and winter avian surveys; amphibian and reptile surveys; deployment of game cameras; animal track and sign identification and movement patterns; vegetation and plant surveys; and a wetland delineation.  Results and trends over a 14-year period have demonstrated not only an increase in wildlife and plant diversity, but an increase in overall abundance and use as well as additional habitat use beyond the Preserve boundaries.  Habitat changes have resulted in some species no longer being present but subsequently replaced with a suite of other species dependent upon an increase of cover, structure, forage availability, nesting or burrowing opportunities, water availability, and other factors.  A new factor to be studied is the effect of climate change on this small-scale Preserve and the surrounding upland desert habitats.

Small Mammals in Northern Hardwoods: How Differing Silvicultural Methods Across Michigan’s Upper Peninsula Affect Diversity
Breanna Gusick, Kristin Brzeski, Yvette Dickinson, Jared Wolfe

Small mammal populations, and predators reliant upon them as food sources, are often challenged by conflicting objectives of timber extraction and maintenance of quality habitat. Nowhere has this challenge been more daunting than in Michigan’s vast Upper Peninsula, where 72% of the landscape is forested, and a third of the land is privately owned by individuals and families. To assess the effects of various logging practices on small mammal populations in the Upper Peninsula, we trapped small mammals in experimental silviculture plots whereby treatments varied by amount of canopy cover and site preparations (tip-up and scarification), and deer exclosures. We used capture data from experimental treatments to estimate small mammal richness, variation in community structure, and differences in relative abundance across treatments. Our results suggested that increased canopy cover resulted in more community stability,  whereby clearcut replicates exhibited highly variable small mammal communities with dissimilar abundances. Conversely, small mammal communities varied slightly across understory preparations, while species-richness estimates were most diverse within single tree selection canopy preparations. When incorporated into the planning process, our suggested management action can increase food resources for predators in working landscapes. Ultimately, our results can be applied to larger spatial scales, with potential to influence wildlife and timber management across the northern hardwood bioregion.

A Mechanistic Understanding of How Elk Balance Risks and Rewards When Crossing Highways
Marie-Pier Poulin, Seth G. Cherry, Jerod Merkle

Roads and their associated traffic represent modern risks for wildlife. Yet, a detailed and mechanistic understanding of individual and group decision-making processes underlying road crossing behavior in animals is still lacking. We investigated how GPS collared elk (n=12, representing >80% of the adult population) balanced the risks of vehicle traffic with the forage benefits of crossing a major highway in Yoho National Park (Canada) from September to May. We developed a detailed map of forage biomass in the study area by combining field data with remotely sensed environmental layers. Risk was indexed by a traffic counter on the highway. Using hidden Markov movement models and step-selection functions, we found that elk selected for safer and more profitable crossing opportunities at the population-level. The probability of crossing the highway increased with the average time gap between vehicles, and the amount of available biomass of herbs and shrubs at their target location. Our results also suggest that elk habitat selection with respect to the highway varied strongly among individuals. Across individuals, the proportion of weeks when elk selected for safer crossings ranged from 43.8 to 66.0%, and ranged from 16.7 to 37.7% for profitable crossings. We will explain this variation by evaluating how individual- (e.g., boldness, reproductive status) and group-specific (e.g., dominance, social connectedness) characteristics affect how individuals trade-off available food resources and traffic levels. Our study helps understand how individual and group decision-making processes dictate road crossing behavior and thus vehicle-wildlife interactions on highways. Our work also provides information on why elk cross this major road, as there is a proposal to upgrade this section of highway from two to four lanes. Ultimately, our work will provide guidance to managers regarding the prioritization of mitigation efforts (e.g., habitat improvements) and strategies (e.g., reducing speeds) for allowing wildlife to cross highways.

A Holistic Approach to Assessing Nesting Habitat Quality at Multiple Scales
Matthew Gonnerman, Stephanie Shea, Kelsey Sullivan, Pauline Kamath, Erik Blomberg

Ensuring adequate nesting habitat is a key component in the management of avian species. Habitat quality is usually measured as either the probability of selection or success at a given location. Assessments of habitat quality that only focus on one of these aspects has the possibility to result in misleading inferences. Further, either approach is complicated by the scale being considered. Habitat selection occurs across multiple scales, including where individuals establish home ranges, how they use space within their home range prior to nesting, and where nesting takes place. Additionally, individuals collect information about their environment across multiple scales, meaning it is important to consider at what level habitat covariates are quantified. Finally, while these assessments focus on the nest location and its success, how habitat influences individual survival is also an important component of quality. A true assessment of nesting habitat quality will therefore need to account for selection, success, and survival across multiple scales. We demonstrate a holistic approach for assessing nesting habitat quality using wild turkeys in Maine as our focal species. We deployed radio and GPS transmitters on wild turkey hens from 2018 through 2020 and monitored hen movements, hen survival, and nesting activity across three years. We used resource selection functions to estimate pre-laying, laying, and nest site habitat selection. We used a daily and weekly survival rate model to estimate nest success and hen survival respectively. For all metrics, we used Bayesian latent indicator scale selection to quantify and incorporate multiple scales of habitat covariate measurements to determine at which level they explained variation in parameters of interest. All metrics were quantified simultaneously to produce a final estimate of nesting habitat quality. We then used this model to project nesting habitat quality for wild turkeys across Maine’s landscape.

Small but Mighty: Influences of Lemming Population Cycles and Engineering Activities on Ecosystem Function
Austin Roy, Jennie McLaren

Small mammals are widely recognized for their impacts on arctic ecosystems as consumers and as prey, but little is known about their role as ecosystem engineers in determining biogeochemical cycling and habitat productivity. While small mammal-created structures have the potential to greatly influence ecosystems, the degree of impacts of these structures likely varies by their type and abundance. Our aim was to determine how structures built by brown lemmings (Lemmus trimucronatus), the dominant resident mammalian herbivores, affect arctic nutrient cycling and habitat productivity. We examined the impact of brown lemming structures (nests, latrines, runways, burrows) and carcasses on soil and plant nutrients at different phases of the lemming population cycle (low phase vs high phase). We found that lemming structures cover 1.5-12% of the landscape during low phase and high phase of their population cycles, respectively. The most abundant structures (runways) increased soil carbon (C) pools, while structures with low abundance (nests, burrows, carcasses) strongly increased soil and plant C, nitrogen (N), and phosphorus (P) pools. Increases in the abundance of structures during the high phase of the population cycle may also increase N and P availability and result in a more productive system following a population peak. In addition, due to the longevity of their structures, the impacts of lemmings during the high phase of their cycle may persist across years. We suggest that managing small mammal populations is not only important due to their role as a prey and consumer species, but also because of their regulation of biogeochemical cycling through ecosystem engineering and resulting feedbacks on habitat productivity.

Habitat Structure Across Multiple Spatial Scales Affects Mesopredator Activity in a Restored Grassland Complex, with Potential Consequences for Grassland Birds
Alex Glass, Michael Eichholz

The loss and fragmentation of grassland habitat throughout the midwestern United States has increased both the vulnerability of grassland-dependent wildlife and the importance of grassland management and restoration efforts. One of the potential negative effects of habitat fragmentation is the increased presence of generalist mammalian mesopredators in grasslands, which may be one of the driving forces behind the decline of grassland songbirds in the region. Therefore, an important consideration for managers and conservationists working in grasslands is limiting the negative impact of mesopredators. In this study, we used two years of data from a restored grassland complex in southern Illinois to examine how mesopredator activity was influenced by habitat structure across three spatial scales: local (within-patch) scale, patch scale, and landscape scale. To determine whether a relationship existed between mesopredator activity and grassland bird productivity, we also correlated mesopredator activity indices with daily nest survival and nest density estimates of grassland birds in our study area. We found no evidence of mesopredator activity being influenced by local scale habitat structure, beyond a weak positive association with % woody vegetation in a patch. At the patch scale, mesopredator activity was positively related to the proportion of patch edge comprising roads, as well as the proportion of patch edge comprising water, and edge-interior ratio. At the landscape scale, mesopredator activity was negatively related to % grassland, and positively related to % water, within 400 meters of a patch. We found a significant negative association between mesopredator activity and daily nest survival of grassland birds, and a significant positive association between mesopredator activity and nest density. We recommend that managers concerned with mesopredator activity in grassland patches should limit the amount of roads along grassland perimeters, and maximize the proportion of grassland in the landscape surrounding a patch.

The New Mexico Wildlife Corridors Action Plan Is a Model for Other States
Patricia Cramer, Jean-Luc Cartron, Kenneth Calhoun, Jeffery Gagnon, Mark Watson, James Hirsch, Matthew Haverland, Terry Brennan, Jeanette Walther, Jeremy Romero, Julie Kutz, Chad Loberger, Haley Nelson, Trent Botkin

New Mexico took an important step to ensure that wildlife species and the connectivity of their habitats are best protected with the passage of the 2019 New Mexico Wildlife Corridors Act. The ensuing Wildlife Corridors Action Plan was developed jointly by the New Mexico Department of Transportation (NMDOT), the New Mexico Department of Game and Fish (NMDGF), and an independent research team. The Act focuses on mule deer, elk, pronghorn, bighorn sheep, black bear, and mountain lion, among other species of concern. The Action Plan was developed with Tribal, non-profit, agency, and public input, wildlife-vehicle collision (WVC) reported crash data analyses, wildlife linkage modeling, predicted habitat occupancy models for species of concern, and other inputs to assure a transparent, scientifically objective methodology. The Plan identified the top hotspot locations where WVC crashes were clustered, through an ArcGIS Hotspot Analysis using the Getis-Ord statistic. The top 10 hotspots (based on crashes/ mile/year) were then field evaluated by team ecologists, who then prescribed transportation mitigation solutions along those hotspot segments of road. The top five hotspots were selected for further recommendations by scientists and engineers for transportation mitigation projects based on scoring of: number of wildlife-caused injury crashes, average annual daily traffic, percentage of all crashes involving wildlife, Tribal-nonprofit-agency-public input, land ownership, and predicted distribution of species of concern. The top wildlife linkages were based on linkage modeling of the main six species of concern, GPS and radio collar data, U.S. Secretarial Order 3362 New Mexico priority linkages, and input from NMDGF biologists. The top 5 wildlife linkages were field visited, and prescriptions for transportation-wildlife mitigation were recommended. New Mexico now has a plan for areas in the greatest and most urgent need of wildlife crossing structures and other mitigation to facilitate wildlife movement above and below highways across the state.

Soil Fertility Influence on Forage Quality and Vegetation Structure in Early Successional Plant Communities
Mark Turner, Wade GeFellers, Lindsey Phillips, Bonner Powell, Craig Harper

Early successional plant communities provide habitat components for several wildlife species, including white-tailed deer (Odocoileus virginianus) and wild turkeys (Meleagris gallopavo). Improving forage and cover within these communities is often a management objective, but plant response to disturbance may be limited on nutrient-poor sites. Although little information exists on the effects of soil amendments on forage quality and structure, it is commonly believed that both will respond positively to the application of lime and fertilizer, especially if soil pH and soil nutrients are relatively low. We designed an experiment to test the effects of lime, fertilizer, and lime+fertilizer on forage quality and structure in four fields across Tennessee. We amended soils during spring 2017 and 2018 according to soil test recommendations to raise soil pH to 7.0 and soil nutrients to high levels. We measured vegetation structure and collected young and old plant material from five common early-successional plants: common ragweed (Ambrosia artemisiifolia), horseweed (Conyza canadensis), Canada goldenrod (Solidago canadensis), pokeweed (Phytolacca americana), and blackberry (Rubus canadensis). Soil amendment treatments failed to consistently increase crude protein, calcium, or phosphorus levels in forages that did not already meet the requirements of a lactating doe with twin fawns. Structure was influenced by our treatments, with 71% greater average vegetation height following fertilization and 65% greater following fertilizer+lime application. Visual obstruction also was greater from 50–100 cm, 100–150 cm, and 150–200 cm following fertilizer and lime+fertilizer application. Species composition in early successional communities likely influences forage quality more strongly than soil fertility, but soil amendments may be effective at increasing structure for various wildlife species on sites with low soil productivity.

Bears, Baits, and Berries: How Does Resource Availability Influence Spatiotemporal Behavior of Black Bears?
Emily Holst, Dan Bjornlie, Ryan Kindermann, Daniel Thompson, Joseph Holbrook

Anthropogenic influence on the environment can have varied consequences on animal behavior and foraging tactics. For instance, increased access to anthropogenic food resources in developed areas may bring bears in closer contact with people and result in lower survival or, in the case of agricultural crops or other dispersed resources, may result in increased body condition and survival. The amount and quality of forage is essential for all North American bears as they exhibit breeding and life-history tactics requiring sustained high-quality nutrition throughout the year. Nutritional condition of females directly impacts fecundity as well as recruitment of young into the population. We assessed how black bear (Ursus americanus) resource selection and movement behavior is influenced by human subsidies to food availability (i.e., baiting) during spring and fall hunting seasons in Wyoming. We captured 24 black bears (11 males and 13 females) during the summers of 2019 and 2020 and equipped them with GPS collars. We expected bears to exhibit increased selection for natural forage during fall to support nutritional costs of denning. Spring foraging of natural resources would likely be more diffuse as bears have less nutritional requirements and are inundated with a surge of artificial resources (baits). Individual variation and resource availability impacted selection for natural food sources and movement behavior of bears. For instance, some individuals modulated exploitation of natural foods based on access and proximity to a pulse of human-provided foods in the form of baits. Males and females differed in natural resource use across seasons, but substantial variation remained among individuals within sexes. Understanding how black bears alter behavior as a result of shifts in resource availability and food manipulation advances our knowledge of carnivore resource selection and ultimately provides better strategies for carnivore population management.

Influence of Landscape and Vegetation Characteristics on Herpetofaunal Assemblages in Gulf Coastal Plain Pine Forests
Ethan Royal, Daniel Greene, Darren Miller, J.D. Willson

Longleaf pine (Pinus palustris) savanna once covered much of the southeastern U.S. Coastal Plain and was characterized by open canopy, diverse herbaceous vegetation, and high amounts of bare soil. The unique structural and vegetative conditions of this ecosystem support a diverse group of endemic species, including many reptiles and amphibians. Private working pine (Pinus spp.) forests now occur throughout the southeastern U.S. and have replaced much of the historic longleaf pine savanna. These forests provide appropriate conditions for upland-pine-associated wildlife species if certain structural characteristics are maintained. However, little work has examined herpetofaunal (reptile and amphibian) assemblages in private, working loblolly pine (P. taeda) landscapes, particularly in the western Gulf Coastal Plain. Using repeated field surveys and hierarchical community occupancy models, we examined the herpetofaunal occupancy and species richness across 81 sites spanning gradients of management practices, vegetative conditions, and soil composition in northwestern Louisiana. We documented 43 species of reptiles and amphibians, including nine upland-pine-associated species. Occupancy of upland-pine-associated species was positively associated with open canopy and understory conditions, and sandy soil area. Regenerating pine stands exhibited structural characteristics most similar to mature longleaf pine reference sites. However, vegetation conditions varied widely within management categories depending on landscape characteristics and site-specific disturbance regimes. Sites providing open-canopy conditions were often able to support upland-pine-associated species regardless of overstory type and disturbance method. Alternatively, overall richness of reptiles and amphibians was greatest at sites with moderate canopy cover outside of sandy soil regions. We present evidence that working pine landscapes in the western Gulf Coastal Plain can support diverse herpetofaunal assemblages, including upland-pine-associated species when management practices maintain open-canopy conditions. More broadly, our results provide insight into how forest management practices affect herpetofauna communities and may guide practices that can contribute to the conservation value of working pine forests.

Contributed Oral
Location: Virtual Date: November 2, 2021 Time: 2:00 pm - 3:00 pm