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Browsing by Author "Robinson, Samantha G."

Now showing 1 - 13 of 13
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    Contrasting long-term population trends of beach-nesting shorebirds under shared environmental pressures
    Kwon, Eunbi; Robinson, Samantha G.; Weithman, Chelsea E.; Catlin, Daniel H.; Karpanty, Sarah M.; Altman, Jon; Simons, Theodore R.; Fraser, James D. (Elsevier, 2021-08-01)
    Identifying the drivers of long-term population change is a key goal of ecological studies. It is complicated by extrinsic and intrinsic factors that may covary with time and/or operate on a time lag. For migratory shorebirds that breed on the barrier islands of eastern North America, populations may be limited by the anthropogenic, climatic, biological environments they encounter throughout the annual cycle. Using three-decades (1989–2017) of breeding monitoring data collected by the National Park Service at two national seashores in North Carolina (Hatteras and Lookout), we examined the potential drivers of nesting piping plover (Charadrius melodus) and American oystercatcher (Haematopus palliates) populations. Hatteras had five times more annual visitors than Lookout, and our modelling revealed a strong negative relationship between the population size of breeding plovers and human activity and a positive relationship with protection efforts aimed at reducing disturbance. Breeding and wintering climatic conditions, population productivity, and nesting habitat availability showed only weak effects. Thus, a decade-long decline in plover numbers at both seashores starting in the mid-90s reversed as the parks' visitor counts decreased and stricter protections from potential disturbance were implemented. However, the two sympatric populations of oystercatchers showed the opposite population trends from each other at the neighboring seashores, increasing only on Lookout after a hurricane improved habitat and subsequently the reproductive output. Our study suggests a strong relationship between the anthropogenic environment and the population trend of a threatened species and, simultaneously, the important role of stochastic events in shaping populations of long-lived shorebird species.
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    Demographic Consequences of Conservation Reserve Program Grasslands for Lesser Prairie-Chickens
    Sullins, Daniel S.; Kraft, John D.; Haukos, David A.; Robinson, Samantha G.; Reitz, Jonathan H.; Plumb, Reid T.; Lautenbach, Joseph M.; Lautenbach, Jonathan D.; Sandercock, Brett K.; Hagen, Christian A. (2018-11)
    Knowledge of landscape and regional circumstances where conservation programs are successful on working lands inagricultural production are needed. Convertingmarginal croplands to grasslands using conservation programs such as the United States Department of Agriculture Conservation Reserve Program (CRP) should be beneficial for many grassland-obligate wildlife species; however, addition of CRP grasslands may result indifferent population effects based on regional climate, characteristics of the surrounding landscape, or species planted or established. Within landscapes occupied by lesser prairie-chickens (Tympanuchus pallidicinctus), CRP may provide habitat only for specific life stages and habitat selection for CRP may vary between wet and dry years. Among all study sites, we captured and fitted 280 female lesser prairie-chickens with very high frequency (VHF)- and global positioning system (GPS) transmitters during the spring lekking seasons of 2013-2015 to monitor habitat selection for CRP in regions of varying climate. We also estimated vital rates and habitat selection for 148 individuals, using sites in northwest Kansas, USA. The greatest ecological services of CRP became apparent when examining habitat selection and densities. Nest densities were approximately 3 times greater in CRP grasslands than native working grasslands (i.e., grazed), demonstrating a population-level benefit (CRP = 6.0 nests/10 km(2) +/- 1.29 [ SE], native working grassland = 1.7 nests/10 km(2) +/- 0.62). However, CRP supporting high nest density did not provide brood habitat; 85% of females with broods surviving to 7 days moved their young to other cover types. Regression analyses indicated lesser prairie-chickens were approximately 8 times more likely to use CRP when 5,000-ha landscapes were 70% rather than 20% grassland, indicating variation in the level of ecological services provided by CRP was dependent upon composition of the larger landscape. Further, CRP grasslands were 1.7 times more likely to be used by lesser prairie-chickens in regions receiving 40 cm compared to 70 cm of average annual precipitation and during years of greater drought intensity. Demographic and resource selection analyses revealed that establishing CRP grasslands in northwest Kansas can increase the amount nesting habitat in a region where it may have previously been limited, thereby providing refugia to sustain populations through periods of extreme drought. Nest survival, adult survival during breeding, and nonbreeding season survival did not vary between lesser prairie-chickens that used and did not use CRP grasslands. The finite rate of population growth was also similar for birds using CRP and using only native working grasslands, suggesting that CRP provides habitat similar to that of native working grassland in this region. Overall, lesser prairie-chickens may thrive in landscapes that are a mosaic of native working grassland, CRP grassland, with a minimal amount of cropland, particularly when nesting and brood habitat are in close proximity. (C) 2018 The Wildlife Society
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    Effects of Landscape Characteristics on Annual Survival of Lesser Prairie-Chickens
    Robinson, Samantha G.; Haukos, David A.; Plumb, Reid T.; Kraft, John D.; Sullins, Daniel S.; Lautenbach, Joseph M.; Lautenbach, Jonathan D.; Sandercock, Brett K.; Hagen, Christian A.; Bartuszevige, Anne; Rice, Mindy A. (2018-07)
    Agriculture and development have caused landscape change throughout the southwestern Great Plains in the range of the lesser prairie-chicken (Tympanuchus pallidicinctus). Landscape alteration within the lesser prairie-chicken range may contribute to range contraction and population losses through decreases in survival rates. Our objectives were to determine if: (1) landscape configuration (i.e., the spatial arrangement of habitat) or composition (i.e., the amount of habitat), at the study.site scale, affected annual survival of females, (2) relationships exist between landscape context (i.e., landscape configuration and composition) and weekly survival to assess effects of landscape composition and configuration on lesser prairie-chicken populations, and (3) anthropogenic features influenced daily mortality risk. We captured 170 female lesser prairie-chickens and used very-high-frequency and GPS (Global Positioning System) transmitters to track their movement and survival for 2 y. We used known-fate survival models to test if landscape configuration or composition within three sites in Kansas were related to differences in female survival among sites. In addition we tested for relationships between weekly survival and landscape configuration or composition within home ranges. Finally, we used Andersen-Gill models to test the influence of distance to anthropogenic features on daily mortality risk. Differences in survival were evident between sites with differing landscape compositions as annual survival in Northwestern Kansas (S=0.27) was half that of Clark County, Kansas (S=0.56), which corresponded with 41.9% more grassland on the landscape in Clark County; landscape configuration did not measurably differ among sites. Survival was greater for prairie-chickens with home-ranges that had greater patch richness and in areas with 30% crop and 57% grassland. Female lesser prairie-chickens also experienced greater mortality risk closer to fences at patch edges. Further conversion of grassland landscapes occupied by lesser prairie-chickens should be avoided to reduce habitat loss and fragmentation thresholds that could affect survival. We suggest continued encouragement of Conservation Reserve Program enrollment in western areas of the lesser prairie-chicken range to maintain or increase the amount of grassland to increase annual survival.
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    Factors influencing nesting ecology of lesser prairie-chickens
    Lautenbach, Joseph M.; Haukos, David A.; Sullins, Daniel S.; Hagen, Christian A.; Lautenbach, Jonathan D.; Pitman, James C.; Plumb, Reid T.; Robinson, Samantha G.; Kraft, John D. (2019-01)
    Lesser prairie-chicken (Tympanuchus pallidicinctus) populations have declined since the 1980s. Understanding factors influencing nest-site selection and nest survival are important for conservation and management of lesser prairie-chicken populations. However, >75% of the extant population is in the northern extent of the range where data on breeding season ecology are lacking. We tested factors influencing fine-scale and regional nest-site selection and nest survival across the northern portion of the lesser prairie-chicken range. We trapped and affixed satellite global positioning system and very high frequency transmitters to female lesser prairie-chickens (n = 307) in south-central and western Kansas and eastern Colorado, USA. We located and monitored 257 lesser prairie-chicken nests from 2013 to 2016. We evaluated nest-site selection and nest survival in comparison to vegetation composition and structure. Overall, nest-site selection in relation to vegetation characteristics was similar across our study area. Lesser prairie-chickens selected nest microsites with 75% visual obstruction 2.0-3.5 dm tall and 95.7% of all nests were in habitat with >= 1 dm and <= 4 dm visual obstruction. Nests were located in areas with 6-8% bare ground, on average, avoiding areas with greater percent cover of bare ground. The type of vegetation present was less important than cover of adequate height. Nest survival was maximized when 75% visual obstruction was 2.0-4.0 dm. Nest survival did not vary spatially or among years and generally increased as intensity of drought decreased throughout the study although not significantly. To provide nesting cover considering yearly variation in drought conditions, it is important to maintain residual cover by managing for structural heterogeneity of vegetation. Managing for structural heterogeneity could be accomplished by maintaining or strategically applying practices of the Conservation Reserve Program, using appropriate fire and grazing disturbances in native working grasslands, and establishing site-specific monitoring of vegetation composition and structure. (c) 2018 The Wildlife Society.
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    Hurricane Sandy and engineered response created habitat for a threatened shorebird
    Walker, Katie M.; Fraser, James D.; Catlin, Daniel H.; Ritter, Shannon J.; Robinson, Samantha G.; Bellman, Henrietta A.; DeRose-Wilson, Audrey; Karpanty, Sarah M.; Papa, Steven T. (ESA, 2019-04-22)
    The intensity of Atlantic Ocean hurricanes is predicted to increase, and although disturbance is recognized as a fundamental driver of ecological processes, the benefits of hurricanes to ecological systems are seldom acknowledged. In October 2012, Hurricane Sandy overwashed Fire Island and Westhampton Island, New York. The storm flattened dunes, buried vegetation, and breached the barrier islands in several places. To reduce future overwashing, engineers attempted to stabilize the islands. We studied nest-site selection, suitable habitat, and abundance of a threatened shorebird, the piping plover (Charadrius melodus), before and after Hurricane Sandy. Prior to the hurricane, piping plovers selected nest sites (n = 62) farther from the ocean (x least-cost distance = 82.8 m) and bay (x Euclidean distance = 697.7 m; x least-cost distance = 24,160.6 m) than would be expected if they were selecting nest sites at random. Following the hurricane, piping plovers selected nest sites (n = 45) predominantly in or near storm overwash habitat, which was close to, and had unobstructed walking access to, the ocean (x least-cost distance = 123.4 m) and newly created bayside foraging habitats (x Euclidean distance = 468.0 m; x least-cost distance = 728.9 m). Areas overwashed by the hurricane contained the most suitable piping plover habitat across all new habitat types. Piping plover abundance increased 93% by 2018 from pre-Hurricane Sandy abundances, with most pairs nesting in new habitats. However, only 58% of suitable piping plover habitat was protected from recreational use and few piping plovers used unprotected habitats for nesting. Our results suggest that the ecological benefits of increased storminess may be maximized by coupling coastal stabilization with targeted conservation of storm-created habitats.
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    Identifying the diet of a declining prairie grouse using DNA metabarcoding
    Sullins, Daniel S.; Haukos, David A.; Craine, Joseph M.; Lautenbach, Joseph M.; Robinson, Samantha G.; Lautenbach, Jonathan D.; Kraft, John D.; Plumb, Reid T.; Reitz, Jonathan H.; Sandercock, Brett K.; Fierer, Noah (2018-07)
    Diets during critical brooding and winter periods likely influence the growth of Lesser Prairie-Chicken (Tympanuchus pallidicinctus) populations. During the brooding period, rapidly growing Lesser Prairie-Chicken chicks have high calorie demands and are restricted to foods within immediate surroundings. For adults and juveniles during cold winters, meeting thermoregulatory demands with available food items of limited nutrient content may be challenging. Our objective was to determine the primary animal and plant components of Lesser Prairie-Chicken diets among native prairie, cropland, and Conservation Reserve Program (CRP) fields in Kansas and Colorado, USA, during brooding and winter using a DNA metabarcoding approach. Lesser Prairie-Chicken fecal samples (n = 314) were collected during summer 2014 and winter 2014-2015, DNA was extracted, amplified, and sequenced. A region of the cytochrome oxidase I (COI) gene was sequenced to determine the arthropod component of the diet, and a portion of the trnL intron region was used to determine the plant component. Relying on fecal DNA to quantify dietary composition, as opposed to traditional visual identification of gut contents, revealed a greater proportion of soft-bodied arthropods than previously recorded. Among 80 fecal samples for which threshold arthropod DNA reads were obtained, 35% of the sequences were most likely from Lepidoptera, 26% from Orthoptera, 14% from Araneae, 13% from Hemiptera, and 12% from other orders. Plant sequences from 137 fecal samples were composed of species similar to Ambrosia (27%), followed by species similar to Lactuca or Taraxacum (10%), Medicago (6%), and Triticum (5%). Forbs were the predominant (>50% of reads) plant food consumed during both brood rearing and winter. The importance both of native forbs and of a broad array of arthropods that rely on forbs suggests that disturbance regimes that promote forbs may be crucial in providing food for Lesser Prairie-Chickens in the northern portion of their distribution.
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    Lesser Prairie-Chicken Avoidance of Trees in a Grassland Landscape
    Lautenbach, Joseph M.; Plumb, Reid T.; Robinson, Samantha G.; Hagen, Christian A.; Haukos, David A.; Pitman, James C. (2017-01)
    Grasslands are among the most imperiled ecosystems in North America. Reasons that grasslands are threatened include conversion to row-crop agriculture, fragmentation, and changes in fire regimes. The reduction of fire processes in remaining prairies has resulted in tree encroachment and establishment in grasslands, further reducing grassland quantity and quality. Grassland birds have been experiencing precipitous population declines in recent decades, commensurate with landscape changes to grasslands. The lesser prairie-chicken (Tympanuchus pallidicinctus Ridgway) is a declining species of prairie grouse of conservation concern. We used second-and third-order habitat selection metrics to test if female lesser prairie-chickens avoid grasslands where trees were present. Our results indicated that female lesser prairie-chickens selected habitats avoiding the nearest trees by 283 m on average, nearly twice as far as would be expected at random. Lesser prairie-chickens were 40 times more likely to use habitats with tree densities of 0 trees.ha(-1) than habitats with 5 trees.ha(-1). Probability of use indicated that lesser prairie-chickens were 19 times more likely to use habitats 1000 m from the nearest tree when compared with using habitats 0 m from the nearest tree. Nest survival was not affected at densities <2 trees.ha(-1); however, we could not test if nest survival was affected at greater tree densities as no nests were detected at densities >2 trees.ha(-1). Avoidance of trees could be due to perceived increased predation risk, reduced habitat quality, or a combination of these potentially confounding factors. Preventing further establishment and expansion of trees in landscapes occupied by lesser prairie-chickens could contribute to the continued persistence of the species. Additionally, restoring grasslands through tree removal may facilitate conservation efforts for grassland species such as the lesser prairie-chicken by improving habitat quality and promoting expansion of occupied range. (C) 2017 The Society for Range Management. Published by Elsevier Inc. All rights reserved.
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    Lesser prairie-chicken space use in relation to anthropogenic structures
    Plumb, Reid T.; Lautenbach, Joseph M.; Robinson, Samantha G.; Haukos, David A.; Winder, Virginia L.; Hagen, Christian A.; Sullins, Daniel S.; Pitman, James C.; Dahlgren, David K. (2019-01)
    The Southern Great Plains has been altered by conversion of native grassland to row-crop agriculture, which is considered the primary cause of declining lesser prairie-chicken (Tympanuchus pallidicinctus) populations. However, recent analyses indicate that direct loss of grassland has slowed while lesser prairie-chicken populations continue to decline, suggesting that remaining grasslands potentially suffer from degradation by various land uses (e.g., increased anthropogenic disturbance). Understanding the spatial ecology of lesser prairie-chickens relative to anthropogenic structures is important for conservation planning, habitat management, and infrastructure mitigation. We investigated effects of proximity to anthropogenic structures on home range and nest placement (second-order selection) and within home range space use (third-order selection) of radio-marked lesser prairie-chickens (n = 285) at 2 scales of selection using resource utilization functions and resource selection functions. We collected data from birds marked in the Mixed-Grass Prairie and Short-Grass Prairie ecoregions of Kansas, USA, from 15 March 2013 to 14 March 2016. Home range placement did not vary by region or season, and lesser prairie-chickens placed home ranges farther from powerlines and roads than would be expected at random. As distance increased from 0 to 3 km away from roads and powerlines, the relative probability of home range placement increased 1.66 and 1.54 times, respectively. Distance to powerline was the single most consistent variable negatively affecting nest placement. As the distance from powerline increased from 0 to 3 km, the relative probability of nest placement increased 2.19 times. Distance to oil well did not influence placement of home ranges or nests. When pooled across regions, lesser prairie-chickens exhibited behavioral avoidance of powerlines, roads, and oil wells within their home range. Lesser prairie-chickens, on average, used space at greater intensities within their home range farther from wells, powerlines, and roads than available. Across breeding season phases, we found no evidence of increased behavioral avoidance of anthropogenic structures during the nesting or brooding phases compared to the lekking or post-breeding phases. Within home range space use during the brooding phase was not related to powerlines, wells, or roads. Our results indicate that avoidance of anthropogenic structures may result in functional habitat loss and continued fragmentation of remaining grassland habitat. Reduction or elimination of anthropogenic development in quality lesser prairie-chicken habitat and concentrating new development in already altered areas that are avoided by lesser prairie-chickens and no longer considered available habitat may reduce continued habitat degradation throughout the species' range and aid in population persistence. (c) 2018 The Wildlife Society.
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    Piping plover chick ecology following landscape-level disturbance
    Robinson, Samantha G.; Walker, Katie M.; Bellman, Henrietta A.; Gibson, Daniel; Catlin, Daniel H.; Karpanty, Sarah M.; Ritter, Shannon J.; Fraser, James D. (Wiley, 2023-01)
    Population declines of disturbance-dependent species due to suppression of natural disturbances are realized across ecosystems. The piping plover (Charadrius melodus; plover), a disturbance-dependent and conservation-reliant shorebird that nests on sandy beaches and barrier islands on the Atlantic Coast, was listed under the United States Endangered Species Act in 1986. In 2012, Hurricane Sandy landed on Fire and Westhampton islands, barrier island nesting sites for plovers in New York, USA. Hurricane Sandy was a natural disturbance in this system, creating abundant nesting habitat. The number of chicks produced by a pair, or a population, is a direct measure of reproductive output, and gaining a better understanding of productivity and chick behavior following large-scale habitat creation may improve plover habitat management and potentially species persistence. We evaluated the effects of landscape features on habitat selection, behavior, and survival of plover broods using logistic regression, generalized linear mixed effects models, and survival models. Plover broods selected flatter sites with less dense vegetation than available at random. Chick foraging rates were highest in moist substrates and were lower in areas of higher nesting plover density. Chick survival was greater for broods that hatched earlier in the breeding season and increased as chicks aged. Generally, providing access to sites with flatter, moist substrates will likely result in higher quality brood rearing habitat on the landscape. Ultimately, vegetation removal and habitat management may be needed to reduce plover nesting density and ensure sufficient habitat, which may in turn improve plover chick survival. Moreover, sustaining natural landscape disturbances such as those resulting from storms, and not taking actions to prevent hurricane-created overwash, will allow these landscape features to persist.
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    Piping plover habitat and demography following storm-induced and engineered landscape change
    Robinson, Samantha G. (Virginia Tech, 2020-04-16)
    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.
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    Strategic conservation for lesser prairie-chickens among landscapes of varying anthropogenic influence
    Sullins, Daniel S.; Haukos, David A.; Lautenbach, Joseph M.; Lautenbach, Jonathan D.; Robinson, Samantha G.; Rice, Mindy B.; Sandercock, Brett K.; Kraft, John D.; Plumb, Reid T.; Reitz, Jonathan H.; Hutchinson, J. M. Shawn; Hagen, Christian A. (2019-10)
    For millennia grasslands have provided a myriad of ecosystem services and have been coupled with human resource use. The loss of 46% of grasslands worldwide necessitates the need for conservation that is spatially, temporally, and socioeconomically strategic. In the Southern Great Plains of the United States, conversion of native grasslands to cropland, woody encroachment, and establishment of vertical anthropogenic features have made large intact grasslands rare for lesser prairie-chickens (Tympanuchus pallidicinctus). However, it remains unclear how the spatial distribution of grasslands and anthropogenic features constrain populations and influence conservation. We estimated the distribution of lesser prairie-chickens using data from individuals marked with GPS transmitters in Kansas and Colorado, USA, and empirically derived relationships with anthropogenic structure densities and grassland composition. Our model suggested decreased probability of use in 2-km radius (12.6 km(2)) landscapes that had greater than two vertical features, two oil wells, 8 km of county roads, and 0.15 km of major roads or transmission lines. Predicted probability of use was greatest in 5-km radius landscapes that were 77% grassland. Based on our model predictions, similar to 10% of the current expected lesser prairie-chicken distribution was available as habitat. We used our estimated species distribution to provide spatially explicit prescriptions for CRP enrollment and tree removal in locations most likely to benefit lesser prairie-chickens. Spatially incentivized CRP sign up has the potential to provide 4189 km2 of additional habitat and strategic application of tree removal has the potential to restore 1154 km(2). Tree removal and CRP enrollment are conservation tools that can align with landowner goals and are much more likely to be effective on privately owned working lands.
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    Using GPS location data to assess red fox responses to predator exclosure setup and hatching at shorebird nests
    Black, Kathleen M.; Karpanty, Sarah M.; Robinson, Samantha G.; Bellman, Henrietta A.; Walker, Katie M.; Catlin, Daniel H.; Fraser, James D. (Wiley, 2023-01)
    Wire cages (i.e., predator exclosures) are frequently used to protect shorebird nests from predation. While exclosed nests often have higher survival than unexclosed nests, concerns exist over whether the conspicuous structures might draw attention of predators, potentially increasing risks to adults and newly-hatched chicks. We present a new approach to investigating predator responses to exclosures and other stimuli at shorebird nests. We used location data from GPS-collared red foxes (Vulpes vulpes) to examine short-term spatial responses of foxes to exclosure setup and hatching at piping plover (Charadrius melodus) nests on Fire Island, New York. We compared mean distances between fox locations and piping plover nests, and the proportions of fox locations within a 100-m buffer of nests, before and after exclosure setup and before, during, and after hatching. Mean distances from fox locations to nests were similar before versus after exclosure setup (x = 641 m before, 675 m after; permutation test for matched pairs, [PTMP], T = 0.28, P = 0.56, n = 9 foxes), before versus during hatching (x = 417 m before, 340 m during; PTMP, T = -0.93, P = 0.18, n = 5 foxes) and during versus after hatching (x = 340 m during, 330 m after; PTMP, T = 1.00, P = 0.84, n = 5 foxes). The proportions of fox locations within 100-m buffers surrounding nests were similar before versus after exclosure setup (x = 0.01 before, 0.03 after; PTMP, T = 0.26, P = 0.53, n = 9 foxes), before versus during hatching (x = 0.04 before, 0.15 during; PTMP, T = -1.44, P = 0.09, n = 5 foxes), and during versus after hatching (x = 0.15 during, 0.14 after; PTMP, T = 0.84, P = 0.80, n = 5 foxes). In 10 of 19 of our individual-level comparisons, there were no significant differences in the distances from fox locations to nests between paired event periods. In the other 9 individual-level comparisons, we found evidence of shifts in fox space use between paired event periods, but no clear directional trend across individuals. We conclude that the foxes in our study did not appear to consistently key in on exclosure setup or hatching at piping plover nests at the spatial scales considered in our comparisons. We recommend that managers continually re-evaluate the effects of exclosures at their management sites, as changes in nest predation, abandonment rates, and adult plover survival may all influence the relative benefit of exclosures for population growth. Our study illustrates the potential for using spatial data to investigate predator responses to various management actions taken to protect nesting shorebirds and other prey species of conservation interest.
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    Using Grazing to Manage Herbaceous Structure for a Heterogeneity-Dependent Bird
    Kraft, John D.; Haukos, David A.; Bain, Matthew R.; Rice, Mindy B.; Robinson, Samantha G.; Sullins, Daniel S.; Hagen, Christian A.; Pitman, James C.; Lautenbach, Joseph M.; Plumb, Reid T.; Lautenbach, Jonathan D. (2021-02)
    Grazing management recommendations often sacrifice the intrinsic heterogeneity of grasslands by prescribing uniform grazing distributions through smaller pastures, increased stocking densities, and reduced grazing periods. The lack of patch-burn grazing in semi-arid landscapes of the western Great Plains in North America requires alternative grazing management strategies to create and maintain heterogeneity of habitat structure (e.g., animal unit distribution, pasture configuration), but knowledge of their effects on grassland fauna is limited. The lesser prairie-chicken (Tympanuchus pallidicinctus), an imperiled, grassland-obligate, native to the southern Great Plains, is an excellent candidate for investigating effects of heterogeneity-based grazing management strategies because it requires diverse microhabitats among life-history stages in a semi-arid landscape. We evaluated influences of heterogeneity-based grazing management strategies on vegetation structure, habitat selection, and nest and adult survival of lesser prairie-chickens in western Kansas, USA. We captured and monitored 116 female lesser prairie-chickens marked with very high frequency (VHF) or global positioning system (GPS) transmitters and collected landscape-scale vegetation and grazing data during 2013-2015. Vegetation structure heterogeneity increased at stocking densities <= 0.26 animal units/ha, where use by nonbreeding female lesser prairie-chickens also increased. Probability of use for nonbreeding lesser prairie-chickens peaked at values of cattle forage use values near 37% and steadily decreased with use >= 40%. Probability of use was positively affected by increasing pasture area. A quadratic relationship existed between growing season deferment and probability of use. We found that 70% of nests were located in grazing units in which grazing pressure was <0.8 animal unit months/ha. Daily nest survival was negatively correlated with grazing pressure. We found no relationship between adult survival and grazing management strategies. Conservation in grasslands expressing flora community composition appropriate for lesser prairie-chickens can maintain appropriate habitat structure heterogeneity through the use of low to moderate stocking densities (<0.26 animal units/ha), greater pasture areas, and site-appropriate deferment periods. Alternative grazing management strategies (e.g., rest-rotation, season-long rest) may be appropriate in grasslands requiring greater heterogeneity or during intensive drought. Grazing management favoring habitat heterogeneity instead of uniform grazing distributions will likely be more conducive for preserving lesser prairie-chicken populations and grassland biodiversity. (c) 2021 The Wildlife Society.