Browsing by Author "Pejchar, Liba, committee member"
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Item Open Access An evidence-based approach to evaluating the outcomes of conservation education(Colorado State University. Libraries, 2015) Thomas, Rebecca E. W., author; Teel, Tara, advisor; Bruyere, Brett, advisor; Gavin, Michael, committee member; Pejchar, Liba, committee memberThis dissertation responds to a need for theoretically-driven and applied approaches to conservation education that address modern-day conservation challenges. The two primary objectives of this dissertation are addressed in the form of two individual articles. First, Article 1 utilizes a systematic review approach to investigate evaluation of conservation education on a global scale in order to better understand 1) the temporal and spatial trends in conservation education program evaluations over the last 25 years (e.g., whether the frequency of program evaluations has changed both within and outside of the United States); 2) patterns that are evident in the types of conservation and/or social issues addressed through these programs; 3) metrics considered to indicate effectiveness of conservation education programs; and 4) which outcomes of these programs are evaluated (e.g., to what extent do evaluations focus on cognitive targets as well as behavioral, social or ecological outcomes) as well as the methods that have been used to draw conclusions about these outcomes. Findings indicated that evaluation of conservation education programs has increased over the last 25 years in countries around the world. Increasingly, conservation education programs are being developed in response to ecological and social issues, yet metrics to indicate effectiveness are rooted in cognition and behavior change. Three primary needs in the field of conservation education program evaluation emerged from this study and can inform the future direction of the field. First, there is a need to think more holistically about the outcomes of conservation education programs. Secondly, there is a need to consider the ways in which these outcomes are evaluated and reported. Finally, there is a need for longitudinal evaluation, particularly when attempting to capture ecological outcomes that may not be immediately apparent. Article 2 utilizes an applied, person-centered interview approach to address a need for more rigorous and culturally relevant evaluation of conservation education program outcomes that is focused on benefits beyond rote knowledge gain and considers community perspectives on metrics or indicators of program success in a rural community in Hawai'i. The study upon which this article is based sought to compare past and present learning about nature in terms of knowledge acquisition and the knowledge itself. Secondly, the study aimed to set the stage for the development of a culturally relevant and comprehensive quantitative evaluation instrument that could be used to document long-term outcomes of conservation education programs that seek to facilitate sharing of local environmental knowledge in Hawai'i.Item Open Access Breeding waterfowl productivity in a flood-irrigated agricultural landscape(Colorado State University. Libraries, 2023) Setash, Casey M., author; Koons, David N., advisor; Pejchar, Liba, committee member; Gammonley, James H., committee member; Sueltenfuss, Jeremy P., committee memberSimilar to agricultural production, the sustainable management of waterfowl populations across the western United States inherently depends on limited water availability. Both endeavors are increasingly challenged by municipal demands for water, drought, and changes in the seasonality of precipitation. Healthy wetlands for wildlife can be sustained in conjunction with the needs of agricultural producers on working lands, but the multifaceted importance of water management is rarely quantified. Information pertaining to the multiple benefits of water management practices might bring to light the larger societal importance of sound water management. This may allow natural resource managers to allocate resources more efficiently and effectively by directing them towards the practices with demonstrated advantages for both wildlife and agricultural producers. The North Platte Basin in north-central Colorado (hereafter North Park) is a model system to evaluate benefits and trade-offs of hydrological manipulations that benefit both agricultural producers and fish and wildlife. Not only are waterfowl and water management already being conducted by federal and state agencies and NGOs like Ducks Unlimited, but North Park is also representative of many working lands throughout the Intermountain West. Agricultural producers in North Park flood irrigate rather than using center-pivot irrigation, which strongly affects on hydrological regimes, water tables, wetlands, and stream flows. Flood irrigation more closely resembles natural stream and river flood regimes and is thought to be more beneficial for wildlife, water table recharge, and evaporative cooling of return flow water. As water resources become diverted for urban municipal uses and the increasing frequency of drought reduces water availability in the semi-arid West, it is believed that the North Platte Basin may begin to play a significant role in the production of waterfowl on a statewide or even a flyway scale. As private land becomes an increasingly important component of waterfowl habitat and water resources become limiting, a strong foundational knowledge regarding how flood-irrigated systems impact wetland-dependent species will therefore be imperative to properly manage waterfowl populations in coordination with agricultural production. We first sought to evaluate the efficacy of flood-irrigated agricultural lands as nesting habitat for breeding waterfowl in the context of land-use intensity. The debate over the best agricultural practices for biological conservation typically focuses on land sharing and land sparing production strategies. One end of the spectrum posits that high-intensity agriculture and the smaller footprint associated with it allows for other land parcels to be spared for biodiversity and therefore provides more suitable habitat, whereas others argue that agricultural lands should be cultivated at a low intensity and interspersed with wildlife habitat, therefore sharing the land with wildlife. We evaluated the demographic consequences of land-sharing and land-sparing practices on breeding bird nest site selection and nest survival, focusing specifically on waterfowl in a flood-irrigated hay agricultural system. We specifically assessed the habitat features related to both shared and spared lands driving nest site selection at two scales and how those same features scaled up to impact nest survival. Nests were located disproportionately closer to uncut irrigated meadows and farther from harvested hay meadows relative to available points, but closer to irrigation ditches. Nests closer to irrigation ditches, uncut irrigated meadows, and open water also experienced higher nest survival. This system is representative of many agricultural systems around the globe and illustrates the ways agricultural practices can shape habitat selection have reproductive consequences for wildlife. After evaluating the importance of wetlands associated with flood irrigation for nesting, we focused our efforts on elucidating their contributions as foraging habitat. Food availability varies considerably over space and time in wetland systems, and consumers must be able to track those changes during energetically-expensive events like breeding. Resource tracking has been studied frequently among herbivores, but rarely receives attention among consumers of macroinvertebrates. We evaluated the change in resource energy density across habitat types and time, and the ability of waterfowl to track macroinvertebrate resources across wetland types and over the course of the breeding season in a high-elevation, flood-irrigated system. We also assessed whether the density of energy resulting from macroinvertebrates explained more of the variation in waterfowl abundance across habitats, or whether the consistency (i.e., temporal evenness) of the resource played a larger role using a pseudo-R2 metric. Energy density varied widely across wetland types, but was highest in basin wetlands (i.e., ponds) and was higher in wetlands with higher temperatures, specific conductivity, and lower dissolved oxygen. Both breeding pair abundance and duckling abundance were positively associated with energy density and resource consistency (R2 = 0.06 for pair abundance and 0.31 for duckling abundance), but energy density explained more of the variation in both waterfowl responses (R2 = 0.77 for pair abundance and 0.58 for duckling abundance). These results have the potential to not only elucidate mechanisms of habitat selection among waterfowl, but also indicate where and when water resources should be allocated as climate conditions become increasingly arid. The technological tools we used initially to evaluate waterfowl use of flood-irrigated habitats (i.e., Global Positioning System [GPS] tags) have become a common tool in ecological studies of animal behavior and demography despite previous research indicating negative impacts on vital rates across a variety of taxa. We therefore focused next on evaluating the impacts of GPS tags on our focal waterfowl species and others across the life-history spectrum. Researchers face tradeoffs when deciding whether they are an appropriate tool because GPS tags may impact vital rates, but they provide detailed data on movements and behavior that often cannot be obtained in other ways. Using band recovery data from hunter harvests, we evaluated the strength of effects induced by GPS tags on annual mortality of adult females across 13 waterfowl species, and whether species with a slower life-history strategy might be more resilient to GPS tag effects than their fast-lived counterparts. Hazard ratios, indicating the risk of death for individuals wearing GPS tags compared to those wearing only metal bands, ranged from 0.92 - 4.38 and the mean difference in survival between marker types across species was 0.31, but these results are averaged across the study period. The magnitude of tag effects remained constant across life-history tempo, indicating that slower-lived species were not able to buffer the effect of wearing GPS tags. When scaling effect sizes up to a currency of fitness, slower-lived species exhibited a similar handicap of wearing GPS tags compared to species with a faster life-history strategy, and the effects were notable. Our results highlight that even small impacts to important vital rates can affect inference pertaining to survival and mortality as well as fitness from birds affixed with GPS tags. The results of this study revealed considerable survival effects across species, although time trends illustrated decreasing effect sizes for most species over time. Results emphasize the importance of testing for such effects in future research as technology advances. Finally, we used components of each previous chapter to characterize the population of breeding ducks in this system and the demographic consequences of environmental conditions. Waterfowl populations in the Intermountain West rely upon water availability and are not as frequently studied as populations within North American core breeding areas like the Prairie Pothole Region. Different species experience different environmental conditions during peak nest initiation depending on their breeding phenology, especially in variable environments like those associated with high-elevation systems. We fit species-specific integrated population models to evaluate the demographic drivers of mallard and gadwall populations breeding in a high-elevation intermountain basin in Colorado representative of many Intermountain West habitats from 2018-2022. Each species initiated nests at opposite ends of the phenological spectrum, allowing us to assess the effects of environmental conditions on demography. Both mallard and gadwall annual after-hatch-year (AHY) female survival probabilities were comparable to estimates from other regions (hatch-year [HY] mallards = 0.48 [SD = 0.09] to 0.53 [SD = 0.07], AHY mallards = 0.53 [SD = 0.07] to 0.57 [SD = 0.05], HY gadwall = 0.44 [SD = 0.13] to 0.52 [SD = 0.14], AHY gadwall = 0.56 [SD = 0.11] to 0. 66 [SD = 0.12]). Annual recruitment, a metric of the number of females produced per breeding pair, was similar among gadwall (0.62 [SD = 0.80] to 1.04 [SD = 1.04]) and mallards (0.40 [SD = 0.48] to 1.59 [SD = 0.95]), but realized population growth rate (λ) did not vary as much for gadwall (0.93 [SD = 0.56] to 1.21 [SD = 0.59]) as it did for mallards (0.76 [SD = 0.24] to 1.55 [SD = 0.24]). Recruitment of both species exhibited quadratic relationships with spring growing degree days, indicating recruitment was higher during springs with intermediate temperatures, and spring snow-water equivalent metrics in the surrounding mountains positively impacted HY and AHY mallard survival in addition to HY gadwall survival. The results of this study emphasize the need for continued monitoring of waterfowl outside of traditional survey areas and provide insight into water management strategies to target important vital rates as climate and land use change.Item Open Access Demographic consequences of agricultural practices on a long-lived avian predator(Colorado State University. Libraries, 2022) Vennum, Christopher Ryan, author; Koons, David N., advisor; Pejchar, Liba, committee member; Kendall, Bill, committee member; Boone, Randall, committee memberTo view the abstract, please see the full text of the document.Item Open Access Effects of birdwatchers on sandhill crane (Grus canadensis) behavior at spring stopover sites in the San Luis Valley, Colorado(Colorado State University. Libraries, 2012) Wilkins, Kate, author; Moore, John, advisor; Bowser, Gillian, advisor; Angeloni, Lisa, committee member; Pejchar, Liba, committee memberHuman recreational activities can disturb wildlife by causing animals to alter feeding patterns, or change feeding locations. Migratory birds in particular can be susceptible to disturbance since they have limited time for resting, feeding and courtship along their migratory routes. Sandhill cranes (Grus canadensis) are an iconic and charismatic species that stop in Colorado's San Luis Valley during each spring and fall migration, which has led to an annual spring bird watching festival at the Monte Vista National Wildlife Refuge. The goal of this research was to understand how birdwatchers drawn by the festival affect the behavior of sandhill cranes in this important migration stopover site. For the purposes of this research, "birdwatchers" are defined as any person present in the pullouts where we conducted observations of crane behavior. The behavior of sandhill cranes was observed using focal animal sampling techniques during March 2010 and 2011 at sites both on and off the Monte Vista National Wildlife Refuge. The number of birdwatchers at a particular site did not affect the time cranes spent in vigilance postures; however, cranes spent more time vigilant on the Monte Vista National Wildlife Refuge than on privately owned lands, where there were fewer observers. Overall, the results of this study suggest that the birdwatchers during the festival had minimal impact on sandhill crane behavior on the refuge, including open lands managed as agricultural fields. The results of this research can inform adaptive management approaches to balance bird watching opportunities and the needs of charismatic migratory species.Item Open Access Gap analysis of India's Western Ghats protected area network: insights from new and understudied endemic species' distributions(Colorado State University. Libraries, 2018) Miltenberger, Oliver, author; Leisz, Stephen, advisor; Evangelista, Paul, committee member; Pejchar, Liba, committee memberProtected areas are a crucial tool to meet conservation goals of the 21st century, especially in biodiverse regions threatened by land use change. This study makes use of nine years of field data collected on over 300 understudied plants and amphibians endemic to the UNESCO-recognized biodiversity hotspot of the Western Ghats of India to produce a gap analysis of its protected area network. The gap analysis updates previous analyses to reassess network coverage and to improve biodiversity distribution estimates. Software for Assisted Habitat Modeling (SAHM) queries possible species distribution models (SDMs) and predictor variables for thirty-five of these species sub-grouped by range strategies. This generates parsimonious sets of predictor variables as well as performance assessments of SDMs, which then populate batch-run distribution Maximum Entropy models (Maxent). These distributions are overlain in various ensembles to produce clade and biodiversity specific insights about high and low-occurrences areas for these species. Hotspot assessments of the region are generated using ensembled distributions and are compared to the current protected area network to identify gaps in coverage for high-occurrences of these species' distributions. Most high species co-occurrences for both amphibian and plant distributions are covered by the network with the exception of three regions for amphibians and six regions for plants, two of which overlap between clades. Previous studies largely or exclusively used secondary-data for their assessments while the majority of species in this study have never been modeled or included in gap analyses. This study's assessment adds new ecological information to individual species and novel contributions to conservation planning in a threatened biodiversity hotspot. This study recommends inclusion of the seven identified high-occurrences areas in future conservation efforts for the Western Ghats and prioritization of the two areas identified as gaps in protection for both clades.Item Open Access Gunnison sage-grouse demography and conservation(Colorado State University. Libraries, 2012) Davis, Amy Jane, author; Doherty, Paul F., advisor; Phillips, Michael L., committee member; Kendall, William, committee member; Pejchar, Liba, committee member; Webb, Colleen, committee memberTo view the abstract, please see the full text of the document.Item Open Access Interactions between Bromus tectorum, grasshoppers, and native plants in sagebrush steppe communities(Colorado State University. Libraries, 2014) Cumberland, Catherine, author; Paschke, Mark, advisor; Cooper, David, committee member; Jonas, Jayne, committee member; Pejchar, Liba, committee memberInvasion by the exotic grass Bromus tectorum L. (cheatgrass) has produced widespread, persistent changes in the Intermountain West. As a result of this and other disturbances, sagebrush shrubland is among North America's most imperiled ecosystems. Restoration of B. tectorum-infested areas has often been unsuccessful, and there is a need to understand the factors limiting revegetation success. There is evidence that B. tectorum is a superior competitor for space and resources. But it's also possible that B. tectorum dominance is enhanced by native herbivores through the mechanism of apparent competition: species competing indirectly through shared natural enemies. If an invasive exotic is a less preferred food source for herbivores than native plants, per capita feeding impacts may increase on natives, thus facilitating exotic proliferation. In sagebrush shrubland, grasshoppers are often the dominant herbivores. Their feeding patterns have been shown to limit and structure plant distributions. The objective of this study was to elucidate whether grasshoppers may be promoting B. tectorum spread through herbivore-mediated apparent competition. Using native plants commonly seeded in sagebrush restoration projects and the native generalist grasshopper Melanoplus bivittatus in laboratory trials and greenhouse experiments, I tested how grasshopper herbivory affects native plants in comparison to B. tectorum. Grasshoppers significantly increased mortality rates for most native plants but had minimal impact on B. tectorum mortality. Certain native species were much more highly preferred and / or impacted by herbivory, including the keystone shrub Artemisia tridentata (big sagebrush). However, several native species were either less preferred or more tolerant of herbivory than B. tectorum, and could therefore be good restoration candidates where grasshoppers are common. In addition, my results suggest B. tectorum could promote population increase in certain grasshopper species, particularly agricultural and rangeland pests. Study results could provide guidance regarding seed mixes and possible control of insect herbivores to improve restoration success in B. tectorum-invaded areas.Item Open Access Population assessment of burrowing owls nesting on black-tailed prairie dog colonies in Colorado(Colorado State University. Libraries, 2024) Albright, Sarah, author; Kendall, William, advisor; Conrey, Reesa, committee member; Pejchar, Liba, committee member; Boone, Randall, committee memberIn North America, grassland birds have experienced steeper and more widespread declines than any other avian guild due to habitat loss resulting from grassland conversion to cropland, increasing urban and energy development, and climate change (Knopf 1994, Askins et al. 2007). The historical area of native grasslands has decreased by 62% since the 1800s and contributed to the loss of nearly 40% of grassland bird populations since 1966 (Wilsey et al. 2019). Heterogeneity in climate, grazing, and fire across the landscape have resulted in the existence of different grassland types that vary in structure and composition. The shortgrass prairie is the driest and warmest of the Great Plains grasslands and is dominated by low-growing perennial grasses, forbs, and shrubs. The shortgrass prairie provides vital nesting and foraging habitat for many grassland birds. In Colorado, approximately 50% of the historic shortgrass prairie has been converted to other land uses (Neely et al. 2006). The partial loss of shortgrass prairie habitat has ecological consequences including loss of native vegetation and decreases in populations of grassland species, including grassland birds. Black-tailed prairie dogs (Cynomys ludovicianus) are important drivers of ecosystem function in the shortgrass prairie because their colonial social structure, burrowing and foraging behaviors alter the landscape and provide areas of shorter vegetation and burrow systems that support increased biodiversity of animals and plants (Cully et al. 2010). Black-tailed prairie dogs function as a keystone species in shortgrass prairie ecosystems and create important breeding and foraging habitat for grassland birds including western burrowing owls (Athene cunicularia hypugaea: Smith and Lomolino 2004). The western burrowing owl is a small diurnal raptor that lives in grasslands, deserts, and other open habitats. It is a partially migratory species where populations in the southern parts of its range in the southwestern United States, Mexico, and portions of Central and South America are typically year-round residents. Migratory populations occur in the grasslands of North America, arriving in early spring to start breeding as far north as Canada and departing in late August to return to their wintering grounds in the southwestern United States and Mexico (Poulin et al. 2011). Burrowing owls typically nest in burrows dug by rodents such as prairie dogs and ground squirrels. In eastern Colorado, burrowing owls almost exclusively nest on black-tailed prairie dog colonies. Benefits of nesting on prairie dog colonies include increased predator detection from alarm calls, decreased predation due to the dilution effect, and reduced vegetation height. Black-tailed prairie dog populations have experienced an estimated decline of 90-98% since 1900 due to sylvatic plague outbreaks and habitat loss and alteration by human development (Miller et al. 1994, Desmond et al. 2000). Since prairie dog colonies provide critical habitat for burrowing owls and other species, population decline contributes to decreased availability of burrowing owl nesting habitat. Conservation status of the burrowing owl varies across its range. It is a species of conservation concern in the western United States, threatened in Mexico, and endangered in Canada (Sheffield 1997). The western burrowing owl is currently listed as a state-threatened species in Colorado and is designated as a Tier 1 Species of Greatest Conservation Need in Colorado's State Wildlife Action Plan (Colorado Parks and Wildlife 2015). The last burrowing owl population assessment in Colorado was conducted in 2005 (Tipton et al. 2008, 2009) and since then, only local surveys limited in spatial and temporal extent have been conducted. This has prompted the need for an updated population assessment of burrowing owls nesting in eastern Colorado, where the majority of Colorado's burrowing owls breed on black-tailed prairie dog colonies. In this study, we provide an updated status assessment for burrowing owls on Colorado's eastern plains and seek to expand the current understanding of which black-tailed prairie dog colony attributes have the highest value for burrowing owl occupancy, density, and productivity. We specifically examined how colony size, activity status, and vegetation characteristics influence these population parameters on 175 survey plots throughout eastern Colorado. We surveyed some of the same plots using similar methodology as Tipton et al. (2008, 2009) in their 2005 study, facilitating comparisons of burrowing owl populations 17–18 years later. The first chapter describes the distribution of burrowing owls nesting on black-tailed prairie dog colonies in eastern Colorado and serves to examine which black-tailed prairie dog colony characteristics drive the use of a colony by burrowing owls and the probability of successful reproduction. The second chapter focuses on burrowing owl density, productivity, and abundance in eastern Colorado to determine how many burrowing owls are present on occupied colonies and how productive they are on colonies where they do reproduce. The value of describing these components of burrowing owl populations in separate chapters comes from estimating and identifying the drivers of burrowing owl occupancy in chapter 1, then shifting to the finer scale of density to determine if the drivers of burrowing owl distribution are also driving density, productivity, and abundance. We used a black-tailed prairie dog colony shapefile prepared by the Colorado Natural Heritage Program for Colorado Parks and Wildlife in 2020 as our sampling frame. This shapefile includes polygons that represent black-tailed prairie dog colonies with digitized boundaries, created using imagery collected in 2019 by the National Agriculture Imagery Program (NAIP). We used a spatially balanced sampling design to select potential plots and selected new samples for each survey year (2022 and 2023) to maximize sample size and spatial coverage of the large study region. From early May through early August, we conducted four surveys on 175 plots in eastern Colorado, counting all burrowing owls seen, with two visits occurring prior to juvenile emergence and two occurring after. We estimated occupancy using a static multistate occupancy estimation model with two states: 'occupied' and 'occupied with successful reproduction'. We estimated density and abundance using distance sampling methods. We estimated productivity using a zero-inflated beta generalized linear model. We used occupancy data from Tipton et al. (2008) and dynamic occupancy models to evaluate burrowing owl local colonization and local extinction between 2005 and 2022 - 2023. Our analyses indicate that burrowing owl occupancy and density are highest in southern Colorado and lowest in northern Colorado. Colonies with higher prairie dog activity level had higher probability of reproduction and higher densities of adult burrowing owls. Vegetation height was the main driver of juvenile density such that colonies with taller vegetation supported lower densities of juvenile owls. We estimated burrowing owl occupancy to be 0.84 (95% CI [0.62, 0.95]) and probability of successful reproduction on occupied plots to be 0.86 (95% CI [0.70, 0.94]). We estimated an average density of 3.47 (95% CI [2.79, 4.15]) adult owls/km2 prior to juvenile emergence, 8.20 (95% CI [6.39, 10.00]) adult owls/km2 after juvenile emergence, and 18 juveniles/km2 (95% CI [13.86-23.66]). We expanded our density estimates to our sampling frame and estimated that there were 4,913 (95% CI [3,948-5,875]) adult owls prior to juvenile emergence, 11,613 (95% CI [5,333-17,893]) adult owls after juvenile emergence, and 26,580 (95% CI [19,623-33,537]) juvenile burrowing owls on black-tailed prairie dog colonies in eastern Colorado. We found that prairie dog activity had a positive effect on burrowing owl density, successful reproduction, and productivity regardless of prairie dog colony size. This indicates that burrowing owls are effectively utilizing and nesting on small prairie dog colonies in eastern Colorado, which could make them more resilient to breeding season habit loss, fragmentation, or degradation. In addition, we found that northern Colorado had lower burrowing owl occupancy and adult density, but had a similar probability of successful reproduction and juvenile density compared to south and central Colorado. If northern Colorado can sustain stable burrowing owl densities, burrowing owl populations may have enough successful reproduction to maintain stable populations. The covariates we investigated in this study did not adequately explain this spatial pattern. However, it is likely that differences in climate, prairie dog population dynamics, land use, or some other factor could cause differences in local habitat and breeding conditions across Colorado. The previous burrowing owl population assessment in eastern Colorado estimated burrowing owl occupancy to be 0.80 (95% CI [0.66-0.89]), density to be 3.04 adult owls/km2 (95% CI [2.15, 5.13]), and adult abundance to be 3,554 (95% CI [3,928-8,445]) owls in eastern Colorado. This suggests that overall, burrowing owl populations in eastern Colorado are relatively stable and are likely to remain stable if efforts continue to preserve the prairie dog colonies that are vital for burrowing owls during the breeding season. The burrowing owl is a state-threatened species in Colorado at the time of this thesis and thus we recommend future burrowing owl surveys to track population changes through time. Future monitoring efforts can help identify the drivers of burrowing owl population change and clarify the spatial patterns we found. These future efforts should occur more frequently than the ~17 year time period between this population assessment and the last assessment in 2005. We recommend conducting burrowing owl surveys every 5 years because it exceeds the time lag between black-tailed prairie dog colony local extinction and cessation of burrowing owl nesting. In addition, a 5 year time interval coincides with the timing of the Colorado Natural Heritage Program's black-tailed prairie dog mapping efforts in eastern Colorado, from which we constructed our sampling frame. Using updated mapping efforts is vital for monitoring efforts because it may decrease the probability that a plot selected from the sampling frame contains a prairie dog colony that has gone locally extinct. We recommend future efforts should select new plots to survey for burrowing owls in addition to resurveying a subset of the plots from this study. Revisiting sites from this study would be helpful in determining burrowing owl population trends through time, while selecting new plots can increase the spatial coverage of surveys. This 2-year study provides an updated status assessment of burrowing owl populations across the black-tailed prairie dog range in Colorado that will help calibrate burrowing owl population models incorporating prairie dog colony extent, inform future monitoring plans, and help guide conservation of keystone species and their communities.Item Open Access Post-fire vegetation and bird habitat use in piñon-juniper woodlands(Colorado State University. Libraries, 2022) Woolet, Jamie, author; Stevens-Rumann, Camille, advisor; Coop, Jonathan, committee member; Pejchar, Liba, committee memberGlobal climate change has caused fire activity and behavior to shift from historical norms due to hotter and drier conditions. Although the ecological effects of changing fire regimes have been explored in many systems, the resilience of some forest types, such as piñon-juniper, are often overlooked. Piñon-juniper is a dominant forest type in the western US and provides breeding habitat for many obligate or semi-obligate bird species. Similarly, this system is supported by a critical mutualism, where the regeneration and infilling of these trees is reliant on several bird species that disperse piñon pine and juniper seeds. This study aimed to assess woodland resilience by evaluating post-fire forest structure and the associated avian communities one-year and 20+ years post-fire. More specifically, seedling regeneration and the habitat use of piñon-juniper obligate bird species, semi-obligates, piñon seed dispersers, and juniper seed dispersers were compared across burned, refugia, and unburned patches. Replicate patches of each habitat type were selected within three fire locations, and 3-4 bird point count stations and 1 forest inventory plot were established in each patch. No tree regeneration was observed 1-year post-fire, and after 25 years, there were few juniper seedlings and no piñon seedlings observed in burned plots. Seedling regeneration and forest structure in refugia and unburned plots were not different, regardless of fire age. Results from occupancy models indicated that Woodhouse's Scrub-jay, a piñon seed disperser, used all habitats equally. American Robin had the highest habitat use in the recent burned patches. Obligate and semi-obligate bird species had differing responses to habitat types, with the habitat use of Ash-throated Flycatcher and Spotted Towhee not differing across habitat types, Virginia's Warbler having the highest habitat use in old burn and refugia patches, the Gray Vireo, Black-throated Gray Warbler, and Gray Flycatcher having highest habitat use in unburned, refugia, and recent burn patches, and the Blue-grey Gnatcatcher having the highest habitat use in the old burn. While there is a need for longer term studies, our work highlights that even 25 years post-fire, little tree recovery is observed and the associated bird species continue to differ, emphasizing the potential transition or long recovery time in these sensitive areas.Item Embargo Songbird trend estimation and density-habitat relationships to inform and prioritize conifer management in the sagebrush and pinyon-juniper ecotone(Colorado State University. Libraries, 2022) Van Lanen, Nicholas J., author; Aldridge, Cameron L., advisor; Pejchar, Liba, committee member; Koons, David N., committee member; Bailey, Larissa L., committee memberTo view the abstract, please see the full text of the document.Item Open Access The economic consequences of private lands conservation using conservation easements in Colorado(Colorado State University. Libraries, 2019) Swartzentruber, Ryan, author; Seidl, Andrew, advisor; Jablonski, Becca B. R., committee member; Pejchar, Liba, committee memberConservation easements have been used across the United States to preserve natural amenities and compensate landowners for the public goods they provide. From the Farm and Ranch Land Protection Program to the Grassland Reserve Program, Colorado conserves 2.4 million acres of land (Colorado Natural Heritage Program and the Geospatial Centroid, 2018) This thesis explores the economic implications of Federal conservation easements through the Agricultural Conservation Easement Program in Colorado. Using Input-Output modeling I found that conservation easements contributed $176 million to Colorado's economic activity. Further Multi-Region Input-Output models showed that conservation easements support rural counties between $106 million and $112 million more than two counterfactuals I considered: decreasing federal income tax and a zero counterfactual. Further, using benefit transfer analysis, I estimated that all conservation easements in Colorado provide between $40 and $47 billion in ecosystem service benefits to Coloradoans. Using econometric meta-analysis techniques, I estimated that Coloradoans are willing to pay $4.3 billion for all the conserved lands in Colorado. I propose an alternative payment methodology which incentivizes landowners to enroll environmentally important lands rather than using development opportunity costs to determine payments.Item Open Access The physiological condition of orphaned African elephants (Loxodonta africana)(Colorado State University. Libraries, 2021) Parker, Jenna Marie, author; Wittemyer, George, advisor; Crooks, Kevin, committee member; Hobbs, Tom, committee member; Pejchar, Liba, committee memberTo view the abstract, please see the full text of the document.Item Open Access The roles of phenotypic plasticity and adaptation in morphology and performance of an invasive species in a novel habitat(Colorado State University. Libraries, 2020) Jardeleza, Marcel Kate Guarin, author; Hufbauer, Ruth A., advisor; Pearse, Ian S., committee member; Pejchar, Liba, committee member; Ghalambor, Cameron K., committee memberInvasive species spread and thrive across widely variable habitats. Their success in novel environments may be influenced by phenotypic plasticity, which occurs when a genotype can produce multiple phenotypes in response to different environments, or local adaptation, the production of traits that are advantageous under the local environmental conditions regardless of their effects in other habitats. One indication of these non-mutually exclusive processes comes in the form of geographic or elevational clines in phenotypes and genotypes. Drosophilla suzukii is an outstanding example of an invasive species that has established across many diverse environments and exhibits an elevational cline in wing size. In my thesis, with collaborators Jonathan Koch, Ian Pearse, Cameron Ghalambor, and Ruth Hufbauer, I evaluated the degree to which plasticity and genetic differentiation determine differences in wing sizes, and whether plasticity appears to be adaptive or not. I first characterized an elevational cline in wing size in D. suzukii on Hawaii and also evaluated its relative abundance by elevation. I then conducted a reciprocal temperature experiment to understand the mechanisms driving the cline. We found that wing size increased with elevation and that D. suzukii was significantly more abundant in higher elevation sites compared to lower elevation sites. Temperature may be the key driver of wing size variation, with wing size increasing as temperature decreased along the elevational gradient. In the reciprocal temperature experiment, I found that temperature had a strong effect on development time and cooler temperatures took longer to emerge compared to warmer temperatures. The reciprocal temperature experiment further revealed strong phenotypic plasticity. When flies from high and low elevation were reared at a cool temperature comparable to that found at high elevation, they produced larger wings. When reared at a warm temperature comparable to that found at low elevation, they produced smaller wings, which is the same pattern of variation observed in field populations. Additionally, I found significant differences in the number of flies that emerged from the two experimental temperatures. Flies from low and high elevation sites produced similar numbers of offspring at the cool temperature, while high elevation flies produced significantly more offspring at the warm temperature compared to the low elevation flies, despite that temperature being their home temperature. My study revealed strong plasticity in wing size, but no indication of local adaptation. If the wing phenotypes observed in high and low elevation populations in the field represent fit phenotypes, then this plasticity is adaptive. The flies may be exhibiting an "all-purpose genotype" where a fit phenotype is produced across the environmental conditions and there is no selection for adaptation to occur. As evidence continues to mount in support of the highly plastic responses of D. suzukii to temperature, particularly with respect to wing size, and the possible adaptiveness of this response, future studies need to make the direct connection between wing plasticity and adaptation. How an invasive organism responds to different environments determines the extent of its novel range and the places that it will impact. Hawaiian populations of D. suzukii exhibit substantial phenotypic variation in wing size, development time, and offspring production with some genetic component to that plasticity.