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USGS2011

A Markov decision process for managing habitat for Florida scrub-jays

Florida scrub-jays Aphelocoma coerulescens are listed as threatened under the Endangered Species Act due to loss and degradation of scrub habitat. This study concerned the development of an optimal strategy for the restoration and management of scrub habitat at Merritt Island National Wildlife Refuge, which contains one of the few remaining large populations of scrub-jays in Florida. There are documented differences in the reproductive and survival rates of scrubjays among discrete classes of scrub height (<120 cm or "short"; 120-170 cm or "optimal"; .170 cm or "tall"; and a combination of tall and optimal or "mixed"), and our objective was to calculate a state-dependent management strategy that would maximize the long-term growth rate of the resident scrub-jay population. We used aerial imagery with multistate Markov models to estimate annual transition probabilities among the four scrub-height classes under three possible management actions: scrub restoration (mechanical cutting followed by burning), a prescribed burn, or no intervention. A strategy prescribing the optimal management action for management units exhibiting different proportions of scrub-height classes was derived using dynamic programming. Scrub restoration was the optimal management action only in units dominated by mixed and tall scrub, and burning tended to be the optimal action for intermediate levels of short scrub. The optimal action was to do nothing when the amount of short scrub was greater than 30%, because short scrub mostly transitions to optimal height scrub (i.e., that state with the highest demographic success of scrub-jays) in the absence of intervention. Monte Carlo simulation of the optimal policy suggested that some form of management would be required every year. We note, however, that estimates of scrub-height transition probabilities were subject to several sources of uncertainty, and so we explored the management implications of alternative sets of transition probabilities. Generally, our analysis demonstrated the difficulty of managing for a species that requires midsuccessional habitat, and suggests that innovative management tools may be needed to help ensure the persistence of scrub-jays at Merritt Island National Wildlife Refuge. The development of a tailored monitoring program as a component of adaptive management could help reduce uncertainty about controlled and uncontrolled variation in transition probabilities of scrub-height and thus lead to improved decision making.

Florida↗

USGS2011

Secretive marsh aird species co-eccurrences and habitat associations across the midwest, USA

Because secretive marsh birds are difficult to detect, population status and habitat use for these birds are not well known. We conducted repeated surveys for secretive marsh birds across 264 sites in the Upper Mississippi River and Great Lakes Joint Venture region to estimate abundance, occupancy, and detection probabilities during the 2008 and 2009 breeding seasons. We identified species groups based on observed species co-occurrences. Two species, least bittern Ixobrychus exilis and American bittern Botaurus lentiginosus , co-occurred with other species less often than expected by chance, and two species groups, rails (Virginia rail Rallus limicola and sora Porzana carolina ) and open-water birds (pied-billed grebe Podilymbus podiceps , common moorhen Gallinula chloropus , and American coot Fulica americana ; coots were only surveyed in 2009), co-occurred more often than expected by chance. These groupings were consistent between years. We then estimated the relation of these species and groups to landscape and local site characteristics by using zero-inflated abundance models that accounted for incomplete detection. At the landscape level (5-km radius), the amount of emergent herbaceous wetland was positively associated with least bittern occupancy, whereas the amount of woody wetland was negatively associated with least bittern, rail, and open-water bird occupancy. At the local level, habitat variables that were associated with abundance were not consistent among groups or between years, with the exception that both least bitterns and open-water birds had a strong positive association between abundance and water-vegetation interspersion. Land managers interested in marsh bird management or conservation may want to consider focusing efforts on landscapes with high amounts of emergent herbaceous wetland and low amounts of woody wetland, and managing for high amounts of water-vegetation interspersion within the wetland.

Journal of Fish and Wildlife Management↗

USGS2024

Visual interpretation of high-resolution aerial imagery: A tool for land managers

Remotely sensed imagery from various collection platforms (e.g., satellites, crewed and uncrewed aircraft) are used by biologists and other conservation personnel to support management activities ranging from monitoring invasive species to assessing land cover and vegetation characteristics. Although remote sensing–based vegetation indices and models have been developed and used for some management applications, straightforward visual interpretation of imagery by on-the-ground personnel may be a pragmatic approach for obtaining time-sensitive and spatially relevant information to support and guide local management activities. Our primary objective was to qualitatively assess our ability to identify patches of target invasive plant species based on simple visual interpretation of high-resolution aerial imagery. We also sought to compare the high-resolution imagery to widely available imagery (e.g., National Agriculture Imagery Program) to determine the efficacy of each for assessing vegetation communities and land-cover features in support of management activities. To accomplish these objectives, we obtained high-resolution imagery and visually scanned and assessed the imagery by using standard geographic information system software. We were able to differentiate patches of crownvetch Securigera varia (L.) Lassen and wild parsnip Pastinaca sativa L., but not spotted knapweed Centaurea stoebe L. or leafy spurge Euphorbia esula L. The relative success in identifying these species had a relationship to plant characteristics (e.g., flower color and morphology, height), time of year (phenology), patch size and density, and potentially site characteristics such density of the underlying vegetation (e.g., grasses), substrate color characteristics (i.e., color contrast with flowers), and physical disturbance. Our straightforward, qualitative assessment suggests that visual interpretation of high-resolution imagery, but not some lower-resolution imagery, may be an efficient and effective tool for supporting local invasive species management through activities such as monitoring known patches, identifying undetected infestations, assessing management actions, guiding field work, or prioritizing on-the-ground monitoring activities.

Journal of Fish and Wildlife Management↗

USGS2015

New summer areas and mixing of two greater sandhill crane populations in the Intermountain West

Population delineation throughout the annual life cycle for migratory birds is needed to formulate regional and national management and conservation strategies. Despite being well studied continentally, connectivity of sandhill crane Grus canadensis populations throughout the western portion of their North American range remains poorly described. Our objectives were to 1) use global positioning system satellite transmitter terminals to identify summer distributions for the Lower Colorado River Valley Population of greater sandhill cranes Grus canadensis tabida and 2) determine whether intermingling occurs among any of the western greater sandhill crane populations: Rocky Mountain Population, Lower Colorado River Valley Population, and Central Valley Population. Capture and marking occurred during winter and summer on private lands in California and Idaho as well as on two National Wildlife Refuges: Cibola and Sonny Bono Salton Sea National Wildlife Refuges. A majority of marked greater sandhill cranes summered in what is established Lower Colorado River Valley Population breeding areas in northeastern Nevada and southwestern Idaho. A handful of greater sandhill cranes summered outside of traditional breeding areas in west-central Idaho around Cascade Reservoir near Donnelly and Cascade, Idaho. For example, a greater sandhill crane colt captured near Donnelly in July 2014 survived to winter migration and moved south to areas associated with the Rocky Mountain Population. The integration of the greater sandhill crane colt captured near Donnelly provides the first evidence of potential intermingling between the Lower Colorado River Population and Rocky Mountain Population. We suggest continued marking and banding efforts of all three western populations of greater sandhill cranes will accurately delineate population boundaries and connectivity and inform management decisions for the three populations.

Arizona, California, Idaho↗

USGS2012

A national geographic framework for guiding conservation on a landscape scale

The U.S. Fish and Wildlife Service, along with the global conservation community, has recognized that the conservation challenges of the 21st century far exceed the responsibilities and footprint of any individual agency or program. The ecological effects of climate change and other anthropogenic stressors do not recognize geopolitical boundaries and, as such, demand a national geographic framework to provide structure for cross-jurisdictional and landscape-scale conservation strategies. In 2009, a new map of ecologically based conservation regions in which to organize capacity and implement strategic habitat conservation was developed using rapid prototyping and expert elicitation by an interagency team of U.S. Fish and Wildlife Service and U.S. Geological Survey scientists and conservation professionals. Incorporating Bird Conservation Regions, Freshwater Ecoregions, and U.S. Geological Survey hydrologic unit codes, the new geographic framework provides a spatial template for building conservation capacity and focusing biological planning and conservation design efforts. The Department of Interior's Landscape Conservation Cooperatives are being organized in these new conservation regions as multi-stakeholder collaborations for improved conservation science and management.

Journal of Fish and Wildlife Management↗

USGS2024

Nonnative Smallmouth Bass in the Snake River, Idaho: Population dynamics, demographics, and management options

The Snake River in Idaho, USA, supports a popular sport fishery for nonnative Smallmouth Bass Micropterus dolomieu , but there are limited studies on the population dynamics of this introduced species in Idaho and other water systems in the western United States. The purpose of this study was to describe the population dynamics and demographics of Smallmouth Bass in the Snake River, Idaho. In total, we sampled 4,929 Smallmouth Bass during electrofishing surveys on the Snake River (separated into nine segments) and three major tributaries (Boise, Payette, and Weiser rivers). We estimated age for 1,869 Smallmouth Bass sampled from the Snake River ( n = 1,433) and three tributaries ( n = 436). Catch-per-unit-effort for all nine segments combined on the Snake River was 36.6 fish/h (±4.4 SE). In the tributaries, catch-per-unit-effort varied from 43.6 to 125.0 fish/h. Relative weight of all Smallmouth Bass varied from 86 to 107, indicating that fish were in relatively good body condition. Fish in the system grew fast, with relative growth index values often near or exceeding 100 for all age classes. Total annual mortality for the Snake River was 45.1 ± 0.7%, and it was 36.8–40.5% in the tributaries. Furthermore, we estimated exploitation to be 5.3% (90% CI; ±2.2%) for the Snake River and tributaries combined. We used a yield-per-recruit population model to evaluate the effects of varying minimum length limits on the fishery. With the observed population demographics and exploitation rates, increasing the current minimum length limit from 305 mm to 356 or 406 mm would probably have little influence on the number of Smallmouth Bass available to anglers. However, increasing the length limit would result in reduced biomass available for harvest. The potential for recruitment overfishing was minimal for all minimum length limits and levels of exploitation. As such, changes to current harvest regulations do not appear warranted. Our findings provide important information on the population dynamics of Smallmouth Bass that can be useful in evaluating their management across Idaho and in similar systems in western North America.

Idaho↗

USGS2013

Reliability of fish size estimates obtained from multibeam imaging sonar

Multibeam imaging sonars have considerable potential for use in fisheries surveys because the video-like images are easy to interpret, and they contain information about fish size, shape, and swimming behavior, as well as characteristics of occupied habitats. We examined images obtained using a dual-frequency identification sonar (DIDSON) multibeam sonar for Atlantic sturgeon Acipenser oxyrinchus oxyrinchus , striped bass Morone saxatilis , white perch M. americana , and channel catfish Ictalurus punctatus of known size (20–141 cm) to determine the reliability of length estimates. For ranges up to 11 m, percent measurement error (sonar estimate – total length)/total length × 100 varied by species but was not related to the fish's range or aspect angle (orientation relative to the sonar beam). Least-square mean percent error was significantly different from 0.0 for Atlantic sturgeon ( x̄ = −8.34, SE = 2.39) and white perch ( x̄ = 14.48, SE = 3.99) but not striped bass ( x̄ = 3.71, SE = 2.58) or channel catfish ( x̄ = 3.97, SE = 5.16). Underestimating lengths of Atlantic sturgeon may be due to difficulty in detecting the snout or the longer dorsal lobe of the heterocercal tail. White perch was the smallest species tested, and it had the largest percent measurement errors (both positive and negative) and the lowest percentage of images classified as good or acceptable. Automated length estimates for the four species using Echoview software varied with position in the view-field. Estimates tended to be low at more extreme azimuthal angles (fish's angle off-axis within the view-field), but mean and maximum estimates were highly correlated with total length. Software estimates also were biased by fish images partially outside the view-field and when acoustic crosstalk occurred (when a fish perpendicular to the sonar and at relatively close range is detected in the side lobes of adjacent beams). These sources of bias are apparent when files are processed manually and can be filtered out when producing automated software estimates. Multibeam sonar estimates of fish size should be useful for research and management if these potential sources of bias and imprecision are addressed.

Journal of Fish and Wildlife Management↗

USGS2024

Viability modeling for decision support with limited data: A lizard case study

Plateau spot-tailed earless lizards, Holbrookia lacerata, are a species of ground lizard in central Texas that are under review for listing as endangered under the US Endangered Species Act, but heretofore no predictive models of population dynamics or viability have been developed. We used limited available data and published demographic rates in a PVA model to predict future status of these lizards under parametric and ecological uncertainty and temporal variability. Even in cases where data are sparse and life history information are limited, viability models can help clarify the consequences of management choices given the uncertainty. Our model predicted that on average populations will decline in in the future. Quasi-extinction probability was low 20 years into the future but up to 0.60. Extinction risk was highly dependent on the road mortality effect and the proportion of the population exposed to roadways, both of which are currently uncertain quantities. Despite these unknowns, our model enables managers to consider the future abundance and extinction risk for the species and make decisions about management to project the populations and also identifies key uncertainties for future research and monitoring.

Texas↗

USGS2016

Effect of electric barrier on passage and physical condition of juvenile and adult rainbow trout

Electric barriers can inhibit passage and injure fish. Few data exist on electric barrier parameters that minimize these impacts and on how body size affects susceptibility, especially to nontarget fish species. The goal of this study was to determine electric barrier voltage and pulse-width settings that inhibit passage of larger bodied rainbow trout Oncorhynchus mykiss (215–410 mm fork length) while allowing passage of smaller bodied juvenile rainbow trout (52–126 mm) in a static laboratory setting. We exposed rainbow trout to 30-Hz pulsed-direct current voltage gradients (0.00–0.45 V cm −1 ) and pulse widths (0.0–0.7 ms) and recorded their movement, injury incidence, and mortality. No settings tested allowed all juveniles to pass while impeding all adult passage. Juvenile and adult rainbow trout avoided the barrier at higher pulse widths, and fewer rainbow trout passed the barrier at 0.7-ms pulse width compared to 0.1 ms and when the barrier was turned off. We found no effect of voltage gradient on fish passage. No mortality occurred, and we observed external bruising in 5 (7%) juvenile rainbow trout and 15 (21%) adult rainbow trout. This study may aid managers in selecting barrier settings that allow for increased juvenile passage.

Journal of Fish and Wildlife Management↗

USGS2022

Sandhill crane colt survival in Minnesota

Age-structured population models require reliable estimates of cohort-specific survival rates, yet vital rates of younger age classes are often difficult to estimate because of the logistical challenges of monitoring young animals. As part of a study of sandhill cranes Antigone canadensis in the zone of contact between breeding distributions of the Eastern Population and Midcontinent Population in Minnesota, we monitored first summer survival of 34 sandhill cranes (hereafter colts) by using very-high-frequency and global positioning system–global system for mobile communications transmitters. We estimated daily survival probabilities from 19 to 120 d posthatch by using a generalized linear model accounting for interval censoring, resulting in an estimated period survival rate of 0.52 (90% CI, 0.36–0.71) over summer (100 d). Estimated daily probabilities of survival increased as colts became older and fledged (at 70–75 d posthatch), when they presumably became less vulnerable to predation. Causes of mortality were mostly unknown aside from one case of a collision with a vehicle. There is a scarcity of published colt survival rate estimates for sandhill cranes, and what is available varies widely by study site. Region-specific sandhill crane colt survival rate estimates can inform future management efforts and inform population dynamics research and overall natural history knowledge of sandhill cranes.

Minnesota↗

USGS2024

Applying local and global sensitivity analysis to inform bigheaded carp management

Natural resource managers commonly use population-level models to aid in understanding the status of target populations or the potential implications of management actions. Sensitivity analyses, specifically, local sensitivity analysis (LSA) and global sensitivity analysis (GSA), exist as tools to improve understanding of these models, the importance of specific parameters to model outcomes, and the assumptions inherent to population models. However, applied ecology and closely related fields such as fisheries and wildlife management rarely use LSA or GSA. Here, we apply LSA and GSA to the Spatially Explicit Invasive Carp Population model, a population-level model used to simulate and compare management actions on the invasive silver carp Hypophthalmichthys molitrix population in the Illinois River. The spatial structure within the model arises from the navigation “pools” that exist between navigation lock-and-dam in the river and are also the focus of fisheries management in the river. We completed LSA and GSA for two reasons: (1) to compare the importance of model input parameters on simulated model populations and (2) to demonstrate the use of LSA and GSA for population-level models. In our system, the most important sensitivity values generally were detected in Alton Pool. This pool is the farthest downstream and includes a direct connection with the Mississippi River. These results indicate that the population dynamics in Alton Pool are an important driver of the population dynamics throughout the Illinois River. Management outcomes in this system will, therefore, be strongly dependent on the dynamics of Alton Pool.

Illinois↗

USGS2012

Habitat use of woodpeckers in the Big Woods of eastern Arkansas

The Big Woods of eastern Arkansas contain some of the highest densities of woodpeckers recorded within bottomland hardwood forests of the southeastern United States. A better understanding of habitat use patterns by these woodpeckers is a priority for conservationists seeking to maintain these high densities in the Big Woods and the Lower Mississippi Alluvial Valley as a whole. Hence, we used linear mixed-effects and linear models to estimate the importance of habitat characteristics to woodpecker density in the Big Woods during the breeding seasons of 2006 and 2007 and the winter of 2007. Northern flicker Colaptes auratus density was negatively related to tree density both for moderate (. 25 cm diameter at breast height) and larger trees (>61 cm diameter at breast height). Red-headed woodpeckers Melanerpes erythrocephalus also had a negative relationship with density of large (. 61 cm diameter at breast height) trees. Bark disfiguration (an index of tree health) was negatively related to red-bellied woodpecker Melanerpes carolinus and yellow-bellied sapsucker Sphyrapicus varius densities. No measured habitat variables explained pileated woodpecker Dryocopus pileatus density. Overall, the high densities of woodpeckers observed in our study suggest that the current forest management of the Big Woods of Arkansas is meeting the nesting, roosting, and foraging requirements for these birds.

Journal of Fish and Wildlife Management↗

USGS2012

Autumn migration of of Mississippi Flyway mallards as determined by satellite telemetry

We used satellite telemetry to study autumn migration timing, routes, stopover duration, and final destinations of mallards Anas platyrhynchos captured the previous spring in Arkansas from 2004 to 2007. Of those mallards that still had functioning transmitters on September 15 ( n = 55), the average date when autumn migration began was October 23 (SE = 2.62 d; range = September 17–December 7). For those mallards that stopped for >1 d during migration, the average stopover length was 15.4 d (SE = 1.47 d). Ten mallards migrated nonstop to wintering sites. The eastern Dakotas were a heavily utilized stopover area. The total distance migrated per mallard averaged 1,407 km (SE = 89.55 km; range = 142–2,947 km). The average time spent on migration per individual between September 15 and December 15 was 27 d (SE = 2.88 d; range = 2–84 d). The state where most mallards were located on December 15 was Missouri (11) followed by Arkansas (8), while 5 mallards were still in Canada, and only 8 of 43 females and 0 of 10 males were present in Arkansas. The eastern Dakotas are a heavily utilized migration stopover for midcontinent mallards that may require more attention for migration habitat management. The reasons for so few mallards, especially male mallards, returning to Arkansas the following year deserves further research. .

Arkansas↗

USGS2022

Structured decision making to rank North American Wetland Conservation Act proposals within joint venture regions

The North American Wetlands Conservation Act (16 U.S.C. 4401-4412) provided funding and administration for wetland management and conservation projects. The North American Wetland Conservation Fund, enabled in 1989 with the Act, provides financial resources. Resource allocation decisions are based, in part, on regional experts, particularly migratory bird Joint Ventures (JVs) (i.e., partnerships for cooperative planning and coordinated management of the continent’s waterfowl populations and habitats). The JVs evaluate funding proposals submitted with their respective regions each year and make funding recommendations to decision makers. Proposal evaluation procedures differ among JVs, however, it could be helpful to consider a transparent, repeatable, and data-driven framework for prioritization within regions. We used structured decision making and linear additive value models for ranking proposals within JV regions. We used two JVs as case studies and constructed two different value models using JV-specific objectives and weights. The framework was developed through a collaborative process with JV staff and stakeholders. Models were written in Microsoft Excel. To test these models, we used six NAWCA proposals submitted to the Upper Mississippi / Great Lakes Joint Venture in 2016 and seven proposals submitted to the Gulf Coast Joint Venture in 2017. We compared proposal ranks assigned by the value model to ranks assigned by each JV’s management board. Ranks assigned by the value model differed from ranks assigned by the board for the Upper Mississippi / Great Lakes Joint Venture, but not for the Gulf Coast Joint Venture. However, ranks from the value model could change markedly with different objective weights and value functions. The weighted linear value model was beneficial for ranking NAWCA proposals because it allows JVs to treat the ranking as a multiple objective problem and tailor the ranking to their specific regional concerns. We believe a structured decision making approach could be adapted by JV staff to facilitate a systematic and transparent process for proposal ranking by their management boards.

Journal of Fish and Wildlife Management↗

USGS2025

Spatial variation of eDNA detection across an invasion gradient for invasive species monitoring programs

Spatial and temporal distribution data provide critical information for invasive species management. For example, distribution data can help managers with early detections and guiding other response actions. Environmental DNA (eDNA)-based sampling exists as one tool for monitoring invasive species. As part of bigheaded carp Hypophthalmichthys spp. monitoring efforts in the Illinois River, USA, we compared eDNA-based sampling results at multiple habitats across an invasion gradient in 2015. Greater densities of carp occurred downriver in the Illinois River and lower densities occurred upriver. We sampled from five locations along this gradient and from three habitat types (backwater, main channel, and shoreline) within each location. We sampled each location in April and June. A priori , we hypothesized that more eDNA detections would occur downriver, where higher densities of carp occur; that more eDNA detections would occur in backwater habitats compared to areas of the river with more fish movement; and that more eDNA detections would occur in April, because bigheaded carps are thought to use our sampling areas more during the spring. We compared the proportion of samples positive across this gradient, the habitat type, and the two sampling time periods. The most downriver location had the highest proportion of samples with eDNA detections, the backwater habitats had the highest proportion of samples with eDNA detections, and April had more positive detections than June. Our results highlight the importance of sampling across multiple habitat types and across time to gain a clear understanding of distribution when using eDNA-based sampling. Thus, being cognizant of the interactions between seasonal habitat use and eDNA-based detections is important for managers who rely upon eDNA-based monitoring.

Illinois↗

USGS2010

Red-shouldered hawk nesting habitat preference in south Texas

We examined nesting habitat preference by red-shouldered hawks Buteo lineatus using conditional logistic regression on characteristics measured at 27 occupied nest sites and 68 unused sites in 2005–2009 in south Texas. We measured vegetation characteristics of individual trees (nest trees and unused trees) and corresponding 0.04-ha plots. We evaluated the importance of tree and plot characteristics to nesting habitat selection by comparing a priori tree-specific and plot-specific models using Akaike's information criterion. Models with only plot variables carried 14% more weight than models with only center tree variables. The model-averaged odds ratios indicated red-shouldered hawks selected to nest in taller trees and in areas with higher average diameter at breast height than randomly available within the forest stand. Relative to randomly selected areas, each 1-m increase in nest tree height and 1-cm increase in the plot average diameter at breast height increased the probability of selection by 85% and 10%, respectively. Our results indicate that red-shouldered hawks select nesting habitat based on vegetation characteristics of individual trees as well as the 0.04-ha area surrounding the tree. Our results indicate forest management practices resulting in tall forest stands with large average diameter at breast height would benefit red-shouldered hawks in south Texas.

Texas↗

USGS2016

Potential effects of drought on carrying capacity for wintering waterfowl in the Central Valley of California

We used the bioenergetics model TRUEMET to evaluate potential effects of California's recent drought on food supplies for waterfowl wintering in the Central Valley under a range of habitat and waterfowl population scenarios. In nondrought years in the current Central Valley landscape, food supplies are projected to be adequate for waterfowl from fall through early spring (except late March) even if waterfowl populations reach North American Waterfowl Management Plan goals. However, in all drought scenarios that we evaluated, food supplies were projected to be exhausted for ducks by mid- to late winter and by late winter or early spring for geese. For ducks, these results were strongly related to projected declines in winter-flooded rice fields that provide 45% of all the food energy available to ducks in the Central Valley in nondrought water years. Delayed flooding of some managed wetlands may help alleviate food shortages by providing wetland food resources better timed with waterfowl migration and abundance patterns in the Central Valley, as well as reducing the amount of water needed to manage these habitats. However, future research is needed to evaluate the impacts of delayed flooding on waterfowl hunting, and whether California's existing water delivery system would make delayed flooding feasible. Securing adequate water supplies for waterfowl and other wetland-dependent birds is among the greatest challenges facing resource managers in coming years, especially in the increasingly arid western United States.

Journal of Fish and Wildlife Management↗

USGS2021

Northern bobwhite occupancy patterns on multiple spatial scales across Arkansas

Northern bobwhite Colinus virginianus populations have been rapidly declining in the eastern, central, and southern United States for decades. Land use change and an incompatibility between northern bobwhite resource needs and human land use practices have driven declines. Here, we applied occupancy analyses on two spatial scales (state level and ecoregion level) to more than 5,000 northern bobwhite surveys conducted over 6 y across the entire state of Arkansas to explore patterns in occupancy and land use variables, and to identify priority areas for management and conservation. At the state level, northern bobwhite occupied 29% of sites and northern bobwhite were most likely to occur in areas with a high percentage of early successional habitat (grassland, pasture, and shrubland). The statewide model predicted that northern bobwhite were likely to occur (≥ 75% predicted occupancy) in < 20% of the state. Arkansas is comprised of five distinct ecoregions, and analyses at the ecoregion spatial scale showed that habitat associations of northern bobwhite could vary between ecoregions. For example, early successional habitat best predicted northern bobwhite occupancy in both the Arkansas River Valley and Ozark Mountains ecoregions, and other habitat associations such as the proportion of herbaceous habitat and hay-pasture habitat, respectively, further refined predictions. Contrastingly, richness of land cover classes alone best predicted northern bobwhite occupancy in the Ouachita Mountains ecoregion. Ecoregion-level models were thus more discerning than the state-level model and should be more helpful to managers in identifying priority conservation areas. However, in two of five ecoregions, surveys too rarely encountered northern bobwhite to accurately predict their occurrence. We found that likely occupied northern bobwhite habitat lay primarily on private properties (95%), but that numerous public entities own and manage land identified as suitable or likely occupied. We conclude that management of northern bobwhite in Arkansas could benefit from cooperation among state, federal, and military partners, as well as surrounding private landowners and that ecoregion-specific models may be more useful in identifying priority areas for management. Our approach incorporates multiple landscape scales when using remote sensing technology in conjunction with monitoring data and could have important application for the management of northern bobwhite and other grassland bird species.

Arkansas↗