Habitat Ecology & Management V

Contributed Oral

Wildfire Ecology and Forest Management for Spotted Owls, from Conflict to Coexistence
Derek Lee

The spotted owl (Strix occidentalis) has been the center of a multi-decadal conflict caused by competition among people over natural resources. Like most human-wildlife conflicts, the values and economies of the humans involved are the ultimate causes of the conflict. Values and economies evolve faster than wildlife adaptations, and cultural evolution is a prerequisite to achieving coexistence. Recent reviews of scientific evidence regarding wildfire and forest management impacts on spotted owls revealed some counter-intuitive results that seemingly undermined forest management policies across millions of hectares of public lands. Commentaries by scientists and stakeholders presented criticisms of these reviews. Here I review the evidence and criticisms and provide a new interpretation that reconciles seemingly contradictory viewpoints. Scientists are fallable and biased, but accuracy can be assessed through empirical analysis of published work quantifying in-text citation errors. In scientific conflicts, it can be difficult for outsiders to know whose evidence or interpretation to trust. In-text citation error rate can assist policy-making bodies and the courts, by quantifying absolute and relative accuracy of scientists presenting scientific evidence. My hypothesis was that agenda-driven scientists and stakeholders in the spotted owl conflict suffer from ‘information blindness’ to evidence that threatens their values or livelihood. To test my interpretation, I had the reviews and commentaries analyzed to quantify the proportion of text statements that were in accordance with cited data. An important group of stakeholders within the spotted owl conflict had a significantly greater proportion of statements in their writing that were not in accordance with the cited data. Acknowledging the information blindness of agents in a resource conflict has been shown to be useful when navigating from conflict to coexistence.

Baseline Effects of Wildfire on An Old Forest Species and Its Potential to Inform Climate Change Impacts
Jeremy Rockweit, Katie Dugger, Damon Lesmeister, Raymond Davis, Alan B. Franklin, Mark Higley

Disturbance regimes in fire-adapted forests of western North America are changing with fire activity increasing throughout the western U.S. Increasing fire activity can significantly impact forest cover, and in turn the wildlife species inhabiting those forests. The first step in determining how wildlife might respond to shifting disturbance regimes is to understand species response to historical disturbance patterns. The northern spotted owl (Strix occidentalis caurina) inhabits old, fire-adapted forests throughout much of its range and has evolved in this fire-adapted landscape. Its future is imperiled because of multiple stressors including the lingering effects of habitat loss, competition with barred owls (Strix varia), and now a shifting wildfire regime. To better understand how spotted owls might be affected by shifting fire regimes, we leveraged data from 6 long-term demographic study areas located throughout fire-adapted forests to examine wildfire effects on population vital rates. We utilized a Before-After-Control-Impact (BACI) study design in a multistate framework to compare pre- and post-fire apparent survival and movement rates of spotted owls. Our objective was to understand ‘baseline’ fire effects on northern spotted owls and to establish a tolerance threshold, the level of disturbance intensity above which northern spotted owls are adversely impacted by wildfire. Here we report on historical fire effects on northern spotted owls, and how this information might be used by researchers and land managers to begin assessing climate change impacts on the long-term persistence of northern spotted owls.

Fuel Break Effectiveness Linked to Accessibility, Environmental Conditions, and Treatment Type in a Retrospective Assessment of Wildfires Across the Western United States
Brianne Brussee, Cali Roth, Peter Coates, Julia Heinrichs, Mark Ricca, Cameron Aldridge, Michele Crist, Douglas Shinneman

Accelerated cycles of wildfire and annual grass invasion are threatening iconic sagebrush ecosystems of the American West and the species that inhabit them. Therefore, wildfire management is at the core of conservation plans for the sagebrush ecosystem, especially critical habitat for species of conservation concern such as the greater sage-grouse (Centrocercus urophasianus; hereafter sage-grouse). Fuel breaks are a key component wildfire suppression and may minimize catastrophic losses of sagebrush by disrupting fuel continuity, reducing hazardous fuel loads, and facilitating staging fire suppression operations, but an extensive evaluation of effectiveness at broad spatiotemporal scales is lacking. We compiled a comprehensive database of fuel breaks across sage-grouse range and intersected them with wildfire perimeters from the Monitoring Trends in Burn Severity and GeoMAC databases from 1984–2018. We coupled fuel break fire events with environmental data characterizing topography, fuels, fuel break condition and accessibility, and weather in a retrospective analysis to identify conditions related to fuel break effectiveness using a binomial mixed model within a Bayesian framework. We found that fuel breaks with greater contact with larger fires were less likely to be successful. In addition, we identified variation in the effectiveness of fuel break treatments based on the ecosystem’s ability to resist annual grass invasion and recover from wildfire (i.e., resilience). We also found that fuel continuity and fuel break accessibility influenced success. Specifically, greater continuity of fine fuels decreased probability of fuel break success, whereas fuel breaks closer to roads were more likely to be successful. These results can help managers identify areas for fuel break installations and manage tradeoffs between fire suppression and sagebrush disturbance, such as habitat fragmentation caused by fuel breaks. Findings are preliminary and provided for timely best science. 

Sage-Grouse Response to Wildfire: Analyses of Range-Wide Effects and Relationships between Sage-Grouse Demography and Underlying Post-Fire Sagebrush Recovery Processes
Ian Dwight, Peter Coates, Cali Roth, Brian Prochazka, Michael Chenaille, Mark Ricca, Cameron Aldridge, Adrian Monroe, David Pilliod, Matthew Rigge

Wildfire has long-term adverse impacts on greater sage-grouse (Centrocercus urophasianus; hereafter sage-grouse) population persistence within the Great Basin. However, chronic effects of wildfire may vary across the entire distributional range of sage-grouse based on regional variation in climate and ecological properties related to sagebrush (Artemisia spp.) ecosystem resilience and resistance to invasive annual grasses. These properties drive variation in sagebrush recovery after disturbance and are expected to influence changes in sage-grouse population abundance. We extended on previous methods of modeling sage-grouse population rate of change () in the Great Basin to a range-wide study extent and developed an advanced sagebrush recovery model using time series satellite imagery in burned areas over the past 35 years. Specifically, we employed a Bayesian state-space model framework, which relates variation in  to changes in cumulative burned area around leks, while accounting for environmental covariates and Gompertz density dependence. Across the range of sage-grouse, we found support for an interaction between cumulative burned area and a one-year lag effect on summer precipitation. Although the strength of the effect varied among regions, which we delineated by broad-scale clusters of leks grouped by shared climatic conditions, the positive influence of precipitation was typically reduced as the proportion of burned area around leks increased. We then used models to project  over the course of 35-years under different management action scenarios to inform specific actions that reduce cumulative burned areas and neutralize negative impacts of habitat loss. Understanding patterns of variation among broad-scale regions can elucidate wildfire impacts across a large ecological gradient. Findings are preliminary and provided for timely best science. 

What Greens Give Thumper Long Ears and Big Feet, Understanding the Influence of Vegetation on Space Use on Desert Cottontails
Samantha Bundick, Nate Bickford

he Desert Cottontail (Sylvilagus audubonii) is a highly valuable prey species for a

number of predators both terrestrial and avian. However, there is limited data regarding

population density and abundance of the desert cottontail, and the International Union

for Conservation of Nature (IUCN) has specified that their population is declining. Our

objective is to investigate the effects of vegetation patterns on space use and selection

for cottontail rabbits. We are identifying vegetation characteristics that are particularly

important to the future conservation of cottontail rabbits, such as refuge locations. We

have analyzed the fine scale location data of 25 cottontail rabbits using Cellular

Tracking Technologies collars that take locations up to every 10 seconds. To determine

fine-scale vegetation characteristics we utilized high spatial resolution (VHSR) satellite

imagery and object-based imagery analysis (OBIA) to produce resource maps. We then

analyzed the telemetry data with those maps to create resource selection functions

(RSF), which highlight areas of importance. This research will fill in important gaps of

information regarding the second and third order selection of desert cottontail and allow

land managers to identify and promote cottontail habitat.

White-Tailed Deer Foraging Habits in Great Plains Grasslands Near Wooded and Agricultural Habitat Edges
Jacqueline Baum, F. Leland Russell

Effects of herbivores in Great Plains grasslands have fundamentally changed with the extirpation of native large grazers, such as bison (Bison bison). Woody plant expansion into prairies allows new interactions involving herbivores that were previously restricted to forested landscapes, leading to novel edge effects within grassland ecotones. Woody plant encroachment and agricultural expansion has led to highly fragmented grasslands, potentially increasing the magnitude of edge effects mediated by highly mobile organisms, such as white-tailed deer (Odocoileus virginianus). To determine the magnitude, spatial scale, and landscape influence on edge effects mediated by deer on tallgrass plant communities, fragmented prairies in south-central Kansas bordered by either wooded or agricultural edges were surveyed for browse damage. Surveys were conducted in June-July and August-October in 2019 and 2020 at six to ten sites during each survey interval. Data were collected on browsing rates of legumes, non-leguminous forbs, and woody plants at different distances from habitat edges within fragmented prairies along three, 100m transects at each site. Deer browsing patterns showed seasonality where in early summer, the most intense browsing remained near the grassland edge (<20m) and late summer browsing intensity remained constant up to 100m from an edge. Additionally, edge type influenced deer browsing, where wooded edges were more likely to experience higher rates of browsing compared to agricultural edges. Deer preferentially browsed woody species over either legumes and non-leguminous forbs, and legumes over non-leguminous forbs in all surveys. Given the small amount of research that quantifies deer browsing patterns in grasslands, these findings can inform better placement of sensitive plant species within prairie restorations and more efficient, targeted protection of reintroduced plant species.

Scale-Specific Landscape Effects Impose Range-Limiting Constraints on the Distribution of Swift Foxes
Ty Werdel, Colleen Piper, Andrew Ricketts, Matt Peek, Adam Ahlers

Human-modified landscapes can structure species’ distributions and may supplant traditional biotic range-limiting processes. Understanding the direction and scale of these processes is necessary to enhance species conservation efforts.We investigated how the distribution of a prairie-obligate carnivore, swift fox (Vulpes velox), is influenced by landscape change at the extent of their range edge. We also assessed the effects of a popular conservation effort, the Conservation Reserve Program (CRP), on swift fox distributionsWe used three years of presence/absence data (2018-2020) from camera traps at 381 sites to evaluate the spatial distribution of swift fox at their range extent in Kansas, USA. We used Gaussian Kernel functions to identify optimal scales of effect for our measured landscape covariates and multiseason occupancy models to reveal potential range-limiting constraints. Swift fox were more likely to occur at sites with moderate landcover diversity, greater proportion of shortgrass prairie and loamy soil types, and lower proportions of CRP landcover. Swift fox were more likely to colonize sites with less diverse landcover, a greater proportion of loamy soil types, and lower proportions of CRP landcover. Surprisingly, swift fox were insensitive to the amount of agriculture surrounding sites. The presence of loamy soils and distribution of shortgrass prairie ecosystems may shape the outer geographic range limit for swift fox. Concurringly, landscape-scale use of CRP may constrain swift fox distributions at their range edge likely because managed vegetation structure of CRP does not mimic native shortgrass prairie.

The American Badger and the Prairie Games They Play: Habitat and Resource Selection on High Country Grasslands
hunter westacott, Nate Bickford, Samantha Bundick, Eli Wildey
The American Badger (Taxidea taxus), is often seen as a pest or varmint species to the ranching community, but they play a crucial role in shortgrass prairie ecosystems. Due to their reputation, little is known about their behavior and ecology, especially in fragmented and impacted habitats. In North America there has been major loss in native prairie range due to climate change, agriculture and development. Urbanization and habitat fragmentation are major threats to wildlife populations, especially mammalian carnivores. Our objective is to investigate the spatial and temporal movements of the American Badger, and how it relates to the vegetation characteristics, and changes seasonally. We captured and fit Cellular Tracking Technologies PowerTag collars to American Badgers (Taxidea taxus). Cellular Tracking Technologies fine scale location data provide locations up to every ten seconds. We determined fine-scale vegetation characteristics utilizing high spatial resolution (VHSR) satellite imagery and object-based imagery analysis (OBIA) to produce resource maps. We then analyzed the movement data within those maps to created resource selection functions (RSF), which provide insight to the areas that badgers preferentially select. This data will provide information about the second and third order selection of American badgers, and allow conservationists the ability to identify and promote the habitat preferred by the American badger. Along with American Badgers we also collared coyote (Canis Latrans). Through this data we will share some insights into intraguild interactions between badgers and coyotes.
Drought Impacts on Breeding Waterfowl Habitat in California: Implications for Future Water Use

As many as half a million waterfowl and waterbirds are estimated to reside in California over the summer months, but little is known about the availability or quality of their habitats. Wetland size and distribution known to serve as proximate cues for habitat selection by breeding waterfowl in other parts of North America such as the Prairie Pothole Region, however, in heavily modified landscapes such as California’s Central Valley, disturbance from factors such as crop cultivation and urban development may limit access, impact survival and lower reproductive success. Spatial and temporal disparities in environmental resources may provide clearer indications of ultimate habitat selection in a region threatened by water shortages, drought and anthropogenic disturbance. We used a maximum likelihood model selection approach (Akaike’s Information Criterion) to investigate the relative importance of drought severity, wetland area and habitat quality based on a ranked spatial production function accounting for adjacent land use on waterfowl population dynamics over a thirteen-year time period (2007-2019). The time period is significant as California experienced a range of climate extremes from an extended drought (2012-2015) to unprecedented flooding (2016-2017). Over all regions, predicted habitat quality was the best predictor of waterfowl population fluctuations (Akaike weight 0.99). Our modeled habitat quality outperformed all other land use parameters including wetlands alone. However, at the regional level drought severity ranked higher than other variables suggesting that management at the regional scale must account for climate. 

Exploring Beneficial Use of Dredged Materials to Establish Nesting Areas for Coastal Birds
Samantha Collins, Lisa Ferguson, Brittany Morey, Lenore Tedesco

Nesting options for avian species in coastal New Jersey have been limited by dense development and recreational use of barrier island beaches and salt marshes, and are being further constrained by rising sea levels and flood frequency. Projects tailoring sediment management practices to benefit coastal habitat, including the modification or addition of bird nesting areas during routine dredging of navigable channels and inlets, are being explored for augmenting nesting options. Elevation is a key design consideration to meet project objectives related to habitat suitability for target species, but the sustainability of elevation and changes in habitat features over time are relatively unknown. Beneficial use of sandy dredged material was used to create two nesting habitats on tidal salt marshes for Black Skimmer (Rynchops niger) and tern species in 2014 and 2018. A target elevation above 3.6’ NAVD88 was established for these sites based on predictions of local tide levels to contend with flooding from spring tides. We explored differences in habitat features (location, elevation, and vegetation) with nesting composition, density, and success for avian species. Nest success and site selection was highly variable among species and years but we did not document nest loss attributed to flooding for nests above spring high tide. Sensitive avian species nesting in coastal New Jersey often nest on areas in tidal marsh enhanced with dredged material if the site meets elevation requirements necessary to contend with spring tidal levels and provides suitable nesting substrate and vegetation communities. Continued management of enhanced sites will be necessary to ensure conditions for successful nesting (e.g., predator and vegetation management) for target species. Additional studies involving long-term monitoring of these areas are needed to fully understand rates of elevation loss and avian responses to habitat changes to provide recommendations for future restoration plans that target large-scale conservation goals.

Spatial Ecology of Bobcats on Everglades Tree Islands
Katherine Buckman, Laura D’Acunto, Stephanie Romañach, Nathan Dorn

One of the focal areas of mammalian ecology research is the investigation of limiting factors of abundance and distribution. Bobcats (Lynx rufus) are terrestrial mammals that inhabit tree islands of the Everglades wetlands (an expansive shallow wetland). Bobcats presumably move into the wetlands under seasonally shallow water conditions, but during the wet season, tree islands serve as the only refuge (“upland”) habitat. A thorough understanding of how mammals use tree islands is essential for management and restoration efforts in the Everglades. Variation in water levels and the progressive invasion by the Burmese Python (Python bivittatus) are hypothesized to influence mammal occupancy of tree islands. We built detection histories from more than 2,000 bobcat images from camera traps set on 101 tree islands in Water Conservation Area 3 from 2005-2019. We used occupancy models to test various hypotheses about bobcat use of tree islands relative to landscape and hydrologic covariates. We used weekly water depths in the wetlands near each focal island to assess the potential effect of water depth. We also used landscape variables such as tree island size and surrounding upland area to test for effects of upland habitat quantity. Our best initial model indicated bobcat occupancy increased on tree islands with a greater density of other tree islands within 5 km. Models including invasive pythons and habitat interactions (e.g., island density x water depth) are currently in development.

Contributed Oral
Location: Virtual Date: November 5, 2021 Time: 3:00 pm - 4:00 pm