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Robert W. Klaver

Publications and source records attributed to Robert W. Klaver.

At least 19 recordsLinked to original sources
USGS2025

Comparing the efficacy of two immobilization drug combinations for the chemical restraint of bobcats (Lynx rufus)

Chemical immobilization agents that provide rapid induction time, short duration of action, wide margin of safety, and postreversal recovery are important attributes to the handling process of immobilized animals. We evaluated differences in induction, recovery, and physiologic parameters in 23 (13 female, nine adults and four yearlings; 10 male, nine adults and one yearling) free-ranging bobcats ( Lynx rufus ) chemically immobilized with an intramuscular combination of ketamine (10 mg/kg) and xylazine (KX; 1.5 mg/kg; n =11) or a combination of butorphanol (0.8 mg/ kg), azaperone (0.27 mg/kg), and medetomidine (BAM; 0.32 mg/kg; n =12). Induction parameters, time to first effect, hemoglobin oxygen saturation, and anesthesia between bobcats administered KX and BAM were similar. Pulse rate was significantly higher for KX than for BAM. Time to standing and full recovery after reversal were faster for bobcats administered BAM than KX. Six of 11 (55%) bobcats given KX were effectively immobilized with a single injection, and five required additional drugs to allow adequate time for processing. Of 12 bobcats given BAM, six (50%) were effectively immobilized with a single injection, three (25%) individuals were not completely immobilized and required additional doses to allow adequate time for processing, and three (25%) required additional doses after complete arousal during processing. We found that BAM provided reduced sedation and processing times (<30 min), whereas KX provided extended sedation and processing times beyond 30 min. We suggest that researchers increase initial BAM drug volumes for yearling and adult bobcats at time of processing and consider taking appropriate safety precautions when handling free-ranging bobcats.

Journal of Wildlife Diseases↗
USGS2024

Evaluating habitat use and relative abundance of Iowa's river otter with harvest data

The North American river otter ( Lontra canadensis ) was extirpated from much of the United States in the early 20th century due to habitat loss, pollution of waterways, and overharvesting. The Iowa Department of Natural Resources began a river otter reintroduction effort in 1985, which placed otters in 14 sites across the state. Otters have since been known to occur in every county in Iowa and appear to have successfully repopulated their former range throughout the state. Our objective was to relate land cover characteristics and otter abundance using harvest data. We used data collected by agency staff to map the locations of otter harvest in Iowa from 2006 to 2016. We mapped otter harvest locations at the subwatershed level (also called 12-digit Hydrologic Unit Code or HUC-12). We related otter harvest to land cover variables and predicted otter abundance by land cover type. We found that roads, forests, larger waterways, and Ictaluridae (catfish) presence were negatively correlated with otter harvest. Variables positively correlated with otter harvest were areas with greater land cover diversity, wetland patch density, average stream density, and waterway and wetland areas. The land cover model predicted otters in equal or greater numbers than the harvest data in 62.8% of HUC-12s. The areas of greatest otter abundance estimates were located near recreation areas and urban areas, indicating the underutilization of these heavy-trafficked areas by trappers. Areas of fewer predicted otters were not concentrated in a single area of the state but occurred along the Interstate 80 corridor.

Iowa↗
USGS2024

Wildlife stewardship on Tribal lands: Our place is in our soul By Serra J. Hoagland and Steven Albert (Eds.), Baltimore, Maryland: Johns Hopkins University Press. 2023. pp. 432. $59.95 (hardcover). ISBN 978-1-4214-4657-8

Despite thousands of years of land stewardship by Indigenous Peoples, Western ideology and science predominantly influences wildlife management in North America today. Indigenous science and Traditional Ecological Knowledge (TEK) extend beyond the scope of Western science and ecological understanding to include knowledge derived from generations of people living as part of ecosystems (Rinkevich 2008 ). Historically, Western science and TEK have operated separately, resulting in the exclusion of Indigenous Peoples and TEK in wildlife science and management, which has led to significant knowledge gaps in Western science. Today, many practitioners are seeking ways to study and manage wildlife in more inclusive ways that integrate multiple perspectives, including those from Indigenous communities, wildlife managers, researchers, and academics.

Journal of Wildlife Management↗
USGS2024

The relative contributions of habitat area, configuration, and vegetative diversity on snake and lizard presence in agricultural landscapes

Nearly one in five reptile species is at risk of extinction. Changes in habitat area, its configuration, and vegetation diversity could affect habitat use, but their relative importance is understudied. We assessed how these factors affected reptile presence in agricultural landscapes figure in Iowa, United States, using 695 cover boards visited 16,441 times in 2015–2020. Species-wise encounter rates ranged 0.0001–0.012. Eight of 11 species and 54.2% of individuals were species of greatest conservation need. Habitat area, configuration, and vegetation diversity influenced reptile presence similarly. Mean patch occupancy was 0.18 for common garter snake (CG, Thamnophis sirtalis ) and 0.45 for all snakes (AS). Naïve presence was explained by effort (odds ratio [OR] AS = 1.83, OR CG = 1.79), vegetation diversity (OR AS = 1.28, OR CG = 1.28), woody cover (OR AS = 1.24, OR CG = 1.41), and patch size (OR AS = 1.30). Large patch prairies were more likely to contain snakes than other conservation practices ( 𝑟̂ encounter = 0.291), and more likely to contain CG (0.098) than prairie contour strips (0.031), waterways (0.018), grass contour strips (0.016), or terraces (0.015). While we documented low overall reptile presence, their higher presence in large prairie patches underscores the importance of core nature reserves for reptile conservation.

Iowa↗
USGS2024

Habitat amount and edge effects, not perch proximity, nest exposure, or vegetation diversity affect cowbird parasitism in agricultural landscapes

Context Prior research documented relationships between brown-headed cowbird ( Molothrus ater ) brood parasitism and edge effects, proximity of perches, and nest exposure. Those relationships have not been evaluated in agroecosystems containing extremes of fragmentation and vegetation diversity. Objectives We compared three existing hypotheses on how cowbirds locate host nests with two new hypotheses regarding habitat amount and vegetation diversity to determine how the configuration and location of agricultural conservation practices affect grassland bird nest parasitism rates and predicted rates for eight common conservation practices. Methods We assessed cowbird parasitism of grassland bird nests on corn and soybean farms in Iowa, USA, and measured perch proximity, nest exposure, edge effects, habitat amount, and vegetation diversity for each nest. We fit a global generalized linear mixed-effects model and compared importance of model parameters using odds ratios. We predicted parasitism likelihood for every subset model and averaged predictions to explore individual effects. Results The variables that most influenced parasitism rates included main effects for nest initiation day-of-season (OR = 0.71, CI 95 = 0.60–0.84) and the landscape variables of distance to nearest crop edge (0.63, 0.51–0.76) and proportion of grass land cover within 660 m (0.75, 0.57–1.00). We found little support that perch proximity, nest exposure, or native vegetation diversity affected parasitism. We also assessed parasitism likelihood by conservation practice and found no significant differences. Conclusions Our results provide evidence to support the edge effect and habitat amount hypotheses, but not the nest exposure, vegetation diversity, or perch proximity hypotheses.

Iowa↗
USGS2024

Bird community response to field-level integration of prairie strips

Grassland birds are under threat worldwide due to loss of habitat to agriculture. Prairie strips are a new agricultural conservation practice composed of linear strips of reconstructed diverse, native, herbaceous, perennial vegetation designed to promote land sharing among agriculture and biodiversity, while also addressing soil and water conservation goals. We evaluated bird community response to establishment of prairie strips on commercial row-crop fields (corn [( Zea mays ] and soybean [ Glycine max ]) in Iowa, USA compared to controls fields without prairie strips, from 2015 to 2020. We found a 2.94-fold higher density of grassland birds on fields with prairie strips compared to control fields, and a 1.87-fold higher density of birds overall. Time since prairie strip establishment was a significant predictor of grassland bird density, with significant increases between years 1 and 2 and years 3 and 4. Species with the strongest positive response to prairie strips were Red-winged Blackbird ( Agelaius phoeniceus ), Common Yellowthroat ( Geothlypis trichas ), Western Meadowlark ( Sturnella neglecta ) and two species of greatest conservation need: Dickcissel ( Spiza americana ) and Eastern Meadowlark ( Sturnella magna ). Diversity measures (e.g., Shannon’s and Simpson’s indices) did not differ between fields with prairie strips versus those without. Prairie strips provide quality breeding habitat for a suite of species, including grassland species and those of conservation concern. While improving several bird community measures, prairie strips do not provide habitat for area-sensitive grassland birds. Larger grassland patches are needed, potentially managed as land-sparing reserves, to achieve overall biodiversity goals in agricultural landscapes.

Iowa↗
USGS2023

Influence of camera model and alignment on the performance of paired camera stations

The probability of obtaining images of target species may vary across camera models or relative position of cameras at survey locations. Alignment of cameras within paired camera stations (hereafter, stations) could affect species detection due to issues with image exposure. We quantified effects of 3 camera models and alignment (staggered, offset by a perpendicular distance of 4.6 m, and aligned, directly facing one another) on camera performance in a station design. Mean exposure events (flash from one camera overexposes or underexposes pictures) at aligned stations was 3.93 (SE = 1.01; n = 40), whereas no exposure events were documented at staggered ( n = 36) stations. Overall frequency of exposure events of mammal images at aligned cameras was 44% (68 exposure events/153 images). On average, 8% (range 0−35%) of mammal images from aligned stations were exposure events. We detected no difference ( P = 0.88) in exposure events among paired camera models. Further, we detected no overall differences ( P ≥ 0.07) in paired camera performance (i.e., number of mammal images over survey interval) between aligned or staggered stations, though reliability (i.e., percentage of camera stations that lasted entire survey interval) varied ( P ≤ 0.001) between model types. Research deploying 2 cameras within a camera station framework can eliminate exposure events by using a staggered camera alignment without affecting the number of usable mammal photos. Rigorous field testing prior to deployment of stations is warranted to optimize reliability. One of our low-cost models performed as well as a more expensive model within our paired camera stations at collecting mammal images, and thus could be incorporated into study designs without compromising quality of camera photo data. We suggest a pilot study before large-scale deployment to evaluate reliability and performance of cameras, particularly when deploying multiple models.

Illinois↗
USGS2023

Response of Tiger Salamanders (Ambystoma t. tigrinum) to wetland restoration in a midwestern agricultural landscape, U.S.A.

Since the early 1990s, > 3,000 ha of wetlands (and adjacent prairie) have been restored on the row-crop agricultural landscape of Winnebago County, Iowa, U.S.A. From 2014–2016, we surveyed 45 wetlands among 19 easements for occupancy by Eastern Tiger Salamanders ( Ambystoma tigrinum tigrinum ) and used radio-telemetry to measure their patterns of movement and habitat use. Rates of occupancy increased with wetland age, from < 25% for wetlands 1–2 years old to ∼75% for wetlands > 11 years old. A two-year survey (2014 and 2015) of ten wetlands restored in 2013 showed that nine were occupied after two years; we did not find a relationship between distance to the nearest salamander population and occupancy of newly restored wetlands by salamanders. We tracked 30 salamanders after they left their breeding wetlands for an average of 69±37 d (range = 14–109 d) and relocated them a total of 393 times. Typically, once a salamander left its breeding wetland, it traveled 50–350 m over several days, found a suitable burrow, then remained for much of the rest of the season. Mean daily distances traveled by salamanders were 7.9±5.6 m (range = 0–135 m); the range of maximum straight-line distances moved was 26–659 m; only one individual salamander traveled in a statistically linear path, relative to a random walk. While ∼90% of the landscape was composed of row-crop fields, salamanders used protective grassy habitats (e.g., restored prairie, road ditches) on ∼88% of our observations. Only three salamanders used row-crop fields, and two of them were killed by heavy equipment. Regardless of the terrestrial habitat types used by salamanders, we found them underground on 336 (84.8%) of our observations.

Iowa↗
USGS2023

Book review of America’s public lands: From Yellowstone to Smokey Bear and beyond (2nd edition)

Since the creation of the first public lands in the United States, they have been a source of turmoil, admiration, and prolonged political debate Nevertheless, our public lands have become an intrinsic part of our national identity and economic progress, exemplifying our divergent attitudes towards nature preservation and resource development. With this in mind, Randall K. Wilson makes a case for the value of our national lands in his book, America’s Public Lands: From Yellowstone to Smokey Bear and Beyond. In this second edition, Wilson aims to present the history, challenges, and complex issues surrounding these lands. This edition promises to keep guard of the present while recognizing and dissecting the past that has brought us to where we are.

Journal of Wildlife Management↗
USGS2022

Multi-species amphibian monitoring across a protected landscape: Critical reflections on 15 years of wetland monitoring in Grand Teton and Yellowstone national parks

Widespread amphibian declines were well documented at the end of the 20th century, raising concerns about the need to identify individual and interactive contributors to this global trend. At the same time, there was growing interest in the use of amphibians as ecological indicators. In the United States, wetland and amphibian monitoring programs were launched in some national parks as a necessary first step to evaluating the status and trends of amphibian populations within some of North America’s most protected areas. In Grand Teton and Yellowstone national parks, a multi-species amphibian monitoring program was launched by many of the authors in 2006 and continues to this day. This Viewpoint Article serves as a self-evaluation of our journey from conception through implementation of an ongoing, long-term monitoring program. This self-evaluation should provide a framework and guidance for other monitoring programs. We address whether we are fulfilling the program’s main objective of describing status and trends of the four amphibian species, discuss how a one-size-fits-all monitoring approach does not serve all species equally, and describe opportunities to bolster our core work using emerging statistical approaches and thoughtful integration of remote sensing and molecular tools. We also describe how the data generated over the program’s first 15 years have been useful beyond our initial goal of characterizing status and trend. Notably, our integration of climate datasets has allowed us to describe wetland and species-specific amphibian responses to variations in climate drivers. Documenting climate links to amphibian occurrence and their primary habitats has allowed us to identify which species, habitat types, and subregions within this large, protected landscape are most vulnerable to anticipated climate change. Recognizing that tools and threats change over time, it will be important to adapt our original monitoring design to maximize opportunities and use of resulting information. Maintaining engagement by multiple stakeholders and expanding our funding portfolio will also be necessary to sustain our program into the future. Finally, collaboration has become standard for long-term, cross-jurisdictional, landscape-scale monitoring. We argue that collaborative monitoring facilitates resource sharing, leveraging of limited funds, completion of work, and mutual learning. Such collaboration also increases the efficacy of conservation.

Wyoming↗
USGS2022

Modelling physiological costs to assess impacts of climate change on amphibians in Yellowstone National Park, U.S.A

Amphibians are vital elements of ecosystems, serving as predator and prey. Their biphasic nature makes them dependent on aquatic and terrestrial habitats; as wet-skinned ectotherms, they are vulnerable to a range of environmental threats, including climate change. Yellowstone National Park (YNP) is becoming warmer and drier, and some wetlands important to amphibians have diminished. Continued climate change is predicted to reduce snowpack, soil moisture, and forest cover. We used data from models of future climate and vegetation cover to mechanistically model how climate change might affect the movements of Western Toads ( Anaxyrus boreas ) across the landscape of three test areas in YNP for the years 2050 and 2090, compared to 2000 as a baseline. Least-cost path analysis produced mixed results: for 2050 and 2090, physiological costs of movement increased in one test area and decreased in another; they were mixed in the third. These changes generally reflect the preference by toads for more open forests. Estimating costs for other species of YNP amphibians produced more negative results. For Columbia Spotted Frogs ( Rana luteiventris ) and Boreal Chorus Frogs ( Pseudacris maculata ) (both more aquatic and less adapted to terrestrial habitats), movement costs increased by about 2–15X. Reduced frequency or duration of rain events might limit the nocturnal movements of Western Tiger Salamanders ( Ambystoma mavortium ). Climate change may not have negative impacts on all amphibians throughout YNP, but increased movement costs for terrestrial habitats will accentuate effects of drying wetlands in at least parts of YNP. Land management actions that preserve habitat structure of both forest and low shrub cover may help mitigate continued drying conditions of climate change.

Montana, Wyoming↗
USGS2022

Movement of Canada geese in urban and rural areas of Iowa, USA

Temperate-breeding Canada Goose ( Branta canadensis maxima ) abundance has increased to previously unrecorded levels, providing social, ecological, and economic value. However, there are also costs associated with abundant Canada Geese. Although hunter harvest is a valued, sustainable use of Canada Geese, the adaptability of geese to urban areas may result in lower susceptibility of geese to hunters, potentially reducing the contribution of hunter harvest to conflict reduction. Our goal was to compare movement of geese marked in urban and rural areas to assess efficacy of hunter harvest in managing urban goose populations. We marked 71 adult female Canada Geese during brood-rearing with GPS-GSM transmitters in urban (n = 45) and rural (n = 26) locations in Iowa, USA to monitor movement during the 2018-19 and 2019-20 Mississippi Flyway goose hunting season frameworks. We estimated the mean proportion of locations each group was available for hunter harvest and examined factors affecting home range areas using generalized linear mixed models. Additionally, we estimated habitat selection of urban- and rural-marked geese using a step-selection analysis. Urban geese had a lower proportion of locations in areas available to hunters (0.07 [95% CI: 0.04-0.13]) than rural geese (0.56 [95% CI: 0.34-0.76]), but median home range area was similar for each group and decreased in size from autumn to late winter. Canada Geese marked in urban areas were more likely to select developed areas and less likely to select wetlands than rural geese, and they had high selection of agricultural fields within city limits during goose hunting seasons. Although Canada Geese breeding in urban areas may be less available for hunter harvest, movement data show when and where opportunity exists to increase harvest susceptibility. Canada Goose management could require actions in addition to hunter harvest to achieve goals in urban areas.

Iowa↗
USGS2021

Miniature temperature data loggers increase precision and reduce bias when estimating the daily survival rate for bird nests

Demographic studies of many bird species are challenging because their nests are cryptic, resulting in few nests being found. To maximize statistical power, methods are needed that minimize disturbance while yielding as much information per nest as possible. One way to meet these objectives is to use miniature thermal data loggers to precisely date nest fates. Our objectives, therefore, were to (1) examine the possible effect of thermal data loggers on nest success through hatching by grass- and shrub-nesting songbirds that differed in their parasite egg-accepting and -rejecting behavior, (2) examine the effect of using daily temperature data versus less frequent nest-visit data on statistical power, bias, and precision when estimating the daily survival rate (DSR) for nests, and (3) compare these two approaches using a simulation study and field data. We monitored the survival of nests located in agricultural landscapes and used a binomial logistic regression with main effects for data-loggers and parasite-accepting or -rejecting status and their interaction. We also compared maximum likelihood–derived DSR for differences in estimated rates, precision, and sample sizes with both data collected in the field and simulated with varying sample sizes and visit frequencies. We found no evidence that thermal data loggers had any effect on hatching rates either for all species or for parasite egg-accepting and -rejecting species, separately. Both our simulation and analysis of real nest data indicated that use of data loggers increased the statistical power from each nest studied by increasing effective sample sizes and precision of DSR estimates compared to in-person visits. We also found a negative bias in DSR estimates with longer visit intervals, which use of data-loggers removed. Both the results of simulated- and field-data analyses suggest that future studies of nest survival can be improved by automated nest monitoring by removing a source of bias and providing more time to find additional nests.

Iowa↗
USGS2020

Canada goose survival and recovery rates in urban and rural areas of Iowa, USA

Once extirpated from much of their North American range, temperate-breeding Canada geese ( Branta canadensis maxima ) have reached high abundance. As a result, focus has shifted from restoration to managing harvest and addressing human-goose conflict. Conflict persists or is increasing in urban areas throughout the Mississippi Flyway. Managers need more information regarding demographic rates to determine how hunting affects geese breeding in urban areas and what management actions may be required to achieve management goals. We estimated survival, dead recovery, live recapture, and fidelity probabilities using data from 77,872 Canada geese banded in Iowa, USA, during 1999–2019 using Burnham joint live-dead band recovery models. Factors predicted to affect parameters in candidate models included age (juvenile, subadult, adult), banding site (urban, rural), time, trend, harvest regulation index, and winter severity index. We predicted Canada geese banded in urban areas would have higher survival and lower dead recovery rates than geese banded at rural sites. The top model indicated support for age and banding site effects, and trends in survival and recovery rate (Brownie parameterization). Adult survival was similar for urban (0.75; range = 0.60–0.92) and rural (0.75; range = 0.66–0.82) geese and relatively constant across years. Mean juvenile survival was lower in urban (0.74; range = 0.48–0.93) than rural (0.85; range = 0.68–0.92) areas. Survival increased for urban-banded juveniles and recovery rates increased during liberalization of harvest regulations and decreased after regulations stabilized. Recovery rates of subadults increased for the urban and rural groups. Our results suggest Canada geese breeding in urban areas contribute to harvest and specialized regulations can affect these populations. Harvest regulations in place during our analysis may not have reached a threshold required to observe substantial changes in survival. Current human-goose conflict in urban areas suggests survival has not decreased to a level required to completely address conflict via reduction in goose abundance. Managers may consider additional liberalization of harvest regulations and monitoring via banding to determine to what degree hunter harvest contributes to reducing human-goose conflict and what additional management actions will be required to achieve goals. © 2020 The Wildlife Society.

Iowa↗
USGS2020

Vegetation sampling and management

What is the utility of vegetation measurements for wildlife managers? In the prairie, savanna, tundra, forest, steppe, and wetland regions of the world, mixtures of plant species provide wildlife with food, cover and, in some circumstances, water; the 3 essential habitat elements necessary to sustain viable wildlife populations. We define habitat in reference to use of a vegetation type by an animal (e.g., deer habitat) and vegetation type when referring to differences in vegetation stands (e.g., marsh vegetation type versus tall grass prairie vegetation type; Hall et al. 1997). In strict definition, the variety of wildlife using plants ranges from snails and voles (Microtus spp.) to bison (Bison bison) and elephants (Loxodonta spp.) in uplands and from mosquitoes and ducks to muskrats (Ondatra zibethicus) and manatees (Trichechus manatus) in wetlands. Through evolutionary processes, some wildlife species are totally dependent on vegetation for all annual life requirements, whereas other species use vegetation only for cover or food. Regardless of the role of vegetation in the sustenance of wildlife, any management or research project that requires evaluation of wildlife and vegetation type relationships on a unit of land will necessitate some form of vegetation measurement. The term vegetation can refer to a single plant or species on a specific site or a community in the landscape. Vegetation may occur naturally or be introduced, and may be live or dead. Uses of vegetation measurements are many: (1) evaluation of vegetation response to management practices, (2) estimation of carrying capacity and/or forage production, (3) characterization of cover and habitat components for an endangered species, or (4) long-term monitoring of the general trend of plant vigor or vegetation type condition. Surveying and measuring quantity and quality of vegetation within habitats are basic to wildlife research and management. Grassland, shrubland, and woodland vegetation types are comprised of populations in which individual plants are usually too numerous to inventory completely. Consequently, wildlife biologists usually use sampling techniques to make inferences about the total plant population within a given vegetation type. Vegetation sampling methodologies have evolved within several ecological disciplines (e.g., plant ecology, forestry, rangeland science) and for a variety of management or research objectives (e.g., estimating forage for ungulates, describing habitat use by passerine birds). Description of every method that has been used to sample vegetation is beyond the scope of this chapter. We describe how to measure vegetation structure, which Dansereau (1957) defined as the spatial organization (distribution) of individuals that form a stand. We have organized this chapter into a description of basic methods of vegetation sampling with examples of how those methods have been applied or modified in wildlife research and management. We assume the investigator/reader has adequate knowledge of the concepts of wildlife ecology, primary habitat requirements of wildlife species under study, and ability to systematically identify the species of wildlife and vascular plants within the geographical area of investigation.

Book chapter↗
USGS2019

Characterizing urban butterfly populations: The case for purposive point-count surveys

Developing effective butterfly monitoring strategies is key to understanding how butterflies interact with urban environments, and, in turn, to developing local conservation practices. We investigated two urban habitat types (public gardens and restored/reconstructed prairies) and compared three survey methods (Pollard transects, purposive point counts, and random point counts) to determine which was most productive for detecting butterflies and assessing family diversity. We conducted 66 butterfly surveys by using each method (198 total) from May through September in 2015 and 2016 at six sites (three public gardens and three prairie areas) in Ames, Ankeny and Des Moines, Iowa. All survey methods were used on 11 sampling dates at each site. Overall, we observed 2,227 butterflies representing 38 species: 1,076 in public gardens and 1,151 in prairie areas. We used a smaller data set standardized for survey effort, including 1,361 of these sightings, to compare survey methods and habitat types. Although there were no significant differences in number of butterfly sightings between the two habitats, more sightings (798) were documented by using purposive point counts when compared to Pollard transects (297) or random point counts (266) (for both comparisons, p < 0.0001). Occupancy modeling also indicated that purposive point counts were most effective in detecting certain species of butterflies, most notably those within the Pieridae (whites, sulphurs) and Papilionidae (swallowtails). We conclude that public gardens and restored/reconstructed prairies in urban settings can provide important butterfly habitat, and that purposive point-count surveys are most effective for detecting butterflies in these relatively small-scale landscape features.

Iowa↗
USGS2019

Estimating density and detection of bobcats in fragmented Midwestern landscapes using spatial capture-recapture data from camera traps

Camera-trapping data analyzed with spatially explicit capture–recapture (SCR) models can provide a rigorous method for estimating density of small populations of elusive carnivore species. We sought to develop and evaluate the efficacy of SCR models for estimating density of a presumed low-density bobcat ( Lynx rufus ) population in fragmented landscapes of west-central Illinois, USA. We analyzed camera-trapping data from 49 camera stations in a 1,458-km 2 area deployed over a 77-day period from 1 February to 18 April 2017. Mean operational time of cameras was 52 days (range = 32–67 days). We captured 23 uniquely identifiable bobcats 113 times and recaptured these same individuals 90 times; 15 of 23 (65.2%) individuals were recaptured at ≥2 camera traps. Total number of bobcat capture events was 139, of which 26 (18.7%) were discarded from analyses because of poor image quality or capture of only a part of an animal in photographs. Of 113 capture events used in analyses, 106 (93.8%) and 7 (6.2%) were classified as positive and tentative identifications, respectively; agreement on tentative identifications of bobcats was high (71.4%) among 3 observers. We photographed bobcats at 36 of 49 (73.5%) camera stations, of which 34 stations were used in analyses. We estimated bobcat density at 1.40 individuals (range = 1.00–2.02)/100 km 2 . Our modeled bobcat density estimates are considerably below previously reported densities (30.5 individuals/100 km 2 ) within the state, and among the lowest yet recorded for the species. Nevertheless, use of remote cameras and SCR models was a viable technique for reliably estimating bobcat density across west-central Illinois. Our research establishes ecological benchmarks for understanding potential effects of colonization, habitat fragmentation, and exploitation on future assessments of bobcat density using standardized methodologies that can be compared directly over time. Further application of SCR models that quantify specific costs of animal movements (i.e., least-cost path models) while accounting for landscape connectivity has great utility and relevance for conservation and management of bobcat populations across fragmented Midwestern landscapes.

Illinois↗