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Information on mussel reproductive life history, age, and growth is important for understanding evolutionary and ecological relationships and predicting how species will respond to conserva...

The United States Fish and Wildlife Service (USFWS) uses a Species Status Assessment (SSA) framework to inform Endangered Species Act (ESA) policy decisions. A major challenge for development of SSAs includes inconsistent or incomplete monitoring throughout a species' range, which can result from inadequate time and funding for data collection prior to final rulings. In 2014, the USFWS initiated an SSA for the Sprague's pipit (Anthus spragueii; hereafter pipit), a migratory songbird scheduled for consideration as Threatened or Endangered in fall 2015. At the time, researchers had no field data to identify the spatial distribution of habitat across the geographic extent of the pipit's wintering grounds or to forecast the species' response to probable future scenarios of environmental conditions or conservation efforts during winter. In addition, the timing of the ESA decision precluded range-wide surveys on the pipit's wintering grounds. We present an SSA case study to demonstrate how citizen science and remotely sensed data could be integrated to help inform time-sensitive policy decisions for species of conservation concern. We developed three independent estimates of potential pipit habitat, and we assumed that spatial congruence among models provided increased evidence of habitat likely to support our focal species. We do not suggest that our approach replace more robust analyses, but rather illustrate an alternative strategy to obtain baseline information for SSAs and other policy decisions when data and time are lacking.

Deer–vehicle collisions (DVCs) are a critical cause of mortality for the endangered Odocoileus virginianus clavium (Florida Key Deer; hereafter Key Deer). Extensive research has focused on large-scale Key Deer movements throughout their range and the corresponding relationship to DVCs (e.g., dispersal of juvenile males south across US Highway 1 [US 1]). Far less data are available about the relationships among short-term movement patterns (hourly and daily) of Key Deer, US 1 traffic patterns, and DVCs. We used global positioning system collars to track female Key Deer movements on short time scales on Big Pine Key in the Lower Florida Keys. We then cross-referenced this with US 1 traffic data and DVCs. We found a significant relationship between hourly female Key Deer movement and hourly DVCs throughout the 24-hour daily period (r = 0.505, P = 0.012). Hourly US 1 traffic patterns were significantly related to hourly DVCs only during night periods (r = 0.787, P = 0.012). This information will inform Key Deer management options such as variable timing of vehicle speed enforcement and warning lights along roadways.

Sylvilagus palustris hefneri (Lower Keys Marsh Rabbit [LKMR]) is an endangered subspecies of marsh rabbit found only in the Lower Florida Keys. In September 2017, Hurricane Irma was measured as a Category 4 storm when it passed through the center of the LKMR range causing significant damage to human infrastructure and natural habitats. To assess the impact of Hurricane Irma to LKMR and its habitat, we compared pre- and post-hurricane monitoring data. Overall, 82% of LKMR habitat patches were abandoned, the average number of pellets per sampling plot decreased 94%, and average patch pellet density decreased by 84% following Hurricane Irma. Generally, pellets were found in plots with greater open cover, an intermediate amount of herbaceous and woody cover, and areas with more standing water post-Hurricane Irma. We also observed a slight decrease in signs of Procyon lotor (Raccoon) and Didelphis virginiana (Virginia Opossum). The decrease in rabbit pellets detected after Hurricane Irma is likely attributed to both direct mortality from the storm and flooding, as well as indirect mortality from the loss of critical, salt-sensitive herbaceous cover. Because climate-change models suggest increases in future flooding and hurricane frequency, we recommend that wildlife managers continue to closely monitor the recovery of LKMR populations and their habitat to determine if more active management actions (e.g., habitat remediation, translocations, or captive breeding) are necessary.

Pituophis ruthveni (Louisiana Pinesnake) is one of the rarest snakes in the United States. Efforts to refine existing habitat models that help locate relictual populations and identify potential reintroduction sites are needed. To validate these models, more efficient methods of detection for this rare species must also be developed. Here we expand recent habitat suitability models based on edaphic factors to include mature Pinus (pine) stands that have not been cut for at least 30 years and likely have vegetation structure with the potential to support the species. Our model identified a total of 1652 patches comprising 180,050 ha of potentially suitable habitat, but only 16 (1%) of these patches were more than 1000 ha and considered worthy of conservation attention as potential reintroduction sites. We also visited potentially suitable habitat, as determined by our model, and used camera traps to survey for relictual populations at 7 areas in Texas. We observed 518 snakes of 18 species in 8,388,078 images taken from April to October 2016, but no Louisiana Pinesnakes were detected. The patchiness of the habitat model and failure to detect Louisiana Pinesnakes corroborate independent conclusions that most populations of the species are small, isolated, probably in decline, and possibly extirpated. In the context of this extreme rarity, we believe this study will help manage limited conservation resources by narrowing the search areas for relictual populations, providing a more cost-effective method of surveying those areas, and identifying the best sites for future reintroduction efforts.

The status of endangered Odocoileus virginianus clavium (Key Deer) on outer islands of Florida was unknown following several recent population declines. In response, we opportunistically monitored the western extent of the current range of Key Deer in Flordia using cameras and in-person observations to determine deer presence. We found evidence of Key Deer on islands at the far western edge of their current range such as Lower Sugarloaf Key, Saddlebunch Keys, Boca Chica Key, and the first documented occurrence of Key Deer on East Rockland Key. We recommend more intensive monitoring to determine the extent of the current range use and to calculate a range-wide abundance estimate.

Chagas disease, also known as American trypanosomiasis, is caused by the flagellate protozoan Trypanosoma cruzi. It is a significant health concern in South and Central America, where millions of people are infected or at risk of infection, and is an emerging health concern in the US. The occurrence of Chagas disease in natural environments is supported by mammal host species, but those primary species may vary based on geographic location. In South Texas, the primary host species for the disease is poorly understood, and required a field study to determine the spatial distribution of T. cruzi prevalence in free-ranging mammals. Our study objectives were to determine the spatial distribution and prevalence of T. cruzi parasites in free-ranging mammals. We compared T. cruzi prevalence among species, among vegetative communities, and among different topographies (i.e., floodplain versus upland). From December 2011 through December 2013, 450 blood and tissue samples from geolocated free-ranging wildlife mammal species were analyzed with the use of polymerase chain reaction to detect protozoan T. cruzi DNA. We also calculated mammal abundance with the use of mark-recapture methodology and recorded capture-site characteristics such as vegetation structure. We found that animals in grasslands had a significantly lower infection rate when summed across all species compared with animals in dense hardwoods and semi-improved woodlands (P=0.001). A higher percentage of infections were found in the lower-elevation floodplain-65% (28/43) of animals sampled, compared to upland areas-25% (9/36) of animals sampled. Our study suggested that common free-ranging meso-mammals supported T. cruzi in natural environments and are of public health concern in South Texas. Mitigation strategies should consider a range of management activities to include vegetation management, selective application of insecticides, and changes in human behavior in high-risk areas.

The red foxes (Vulpes vulpes) indigenous to the mountains of the western United States are high-elevation specialists that could face range reduction due to climatic warming, as well as potential encroachment, loss of adaptive alleles, and displacement by introduced nonnative red foxes. We investigated the genetic integrity of the native Rocky Mountain red fox (V. v. macroura) in Colorado through analysis of the composition, distribution, and patterns of gene flow between native and nonnative red fox populations along an elevational gradient. The study area spanned the high plains around Denver in the east to the alpine zone of the Rocky Mountains adjacent to Gunnison and Crested Butte in the west. We used microsatellites and mitochondrial DNA (mtDNA) from Colorado foxes, along with previously published reference data from other native western and nonnative populations, to evaluate the distribution of native versus nonnative ancestry and its relationship to elevation, distance, and landscape type. Nonnative red fox ancestry predominated in Denver and low-lying areas, whereas native ancestry was most prevalent at high elevations. The genetic integrity of foxes at higher elevations (i.e., within the historical native range) was greater in terms of mtDNA than nuclear DNA, consistent with higher male-mediated gene flow. Nonnative admixture was most pronounced in human-altered landscapes. Our findings provide baseline data necessary to monitor future trends of these Rocky Mountain red fox populations and highlight the potential for similar threats to affect genetic integrity of endangered montane red fox subspecies along the Pacific Crest.

Freshwater resources in arid and semi-arid regions are in extreme demand, which creates conflicts between needs of humans and aquatic ecosystems. The Rio Grande basin in the southwestern United States and northern Mexico exemplifies this issue, as much of its aquatic biodiversity is in peril as a result of human activities. Unionid mussels have been disproportionately impacted, though the specific factors responsible for their decline remain largely unknown. This is problematic because the Rio Grande basin harbors one federally endangered unionid mussel (Popenaias popeii, Texas Hornshell) plus two other mussel species (Potamilus metnecktayi, Salina Mucket; and Truncilla cognata, Mexican Fawnsfoot), which are also being considered for listing under the U.S. Endangered Species Act. To date, surveys for these species have not corrected for variability in detection so current range estimates may be inaccurate. Using single occupancy-modeling to estimate detection and occupancy at 115 sites along ~800 river kilometers of the Rio Grande in Texas, we found that detection probabilities were relatively high, indicating that our survey design was efficient. In contrast, the estimated occupancy was low, indicating that our focal species were likely rare within the Rio Grande drainage. In general, the predicted occupancy of our focal species was low throughout their respective ranges, indicating possible range declines. A comparison of currently occupied ranges to presumptive ranges underscores this point. The best-approximating models indicated that occupancy was influenced by habitat, water quantity and quality, and proximity to large-scale human activities, such as dams and major urban centers. We also discuss a series of conservation options that may not only improve the long-term prognosis of our focal species but also other aquatic taxa.

We studied Greater Roadrunner (Geococcyx californianus) habitat use during spring and summer 2011 on the Rolling Plains Quail Research Ranch in the Red Rolling Plains of west Texas. We captured 9 roadrunners (1 male, 8 females) and fitted each with a 10-g backpack-style radio-transmitter. We relocated roadrunners 2–4 times per week from February to August. Roadrunners used a mean minimum convex polygon home range of 43.0 ha, a 50% core range of 11.9 ha, and 33% overlap between adjacent home ranges. Home ranges were approximately half the size of those reported in a recent study of roadrunners in north Texas. Habitat selection ratios showed that roadrunners selected for ridge and grassland vegetation types and avoided bare ground and flatland vegetation types at both first- and second- but not third-order levels of selection. Similar results were documented for roadrunners in north Texas.

Little is known of the greater roadrunner's (Geococcyx californianus; roadrunner) ecology and many demographic questions are difficult to answer because of our inability to determine adult bird sex in the field. We collected measurements from live-captured roadrunners of known sex in Fisher County, Texas, USA, and from roadrunner specimens from museums and university biological collections from 2003 to 2012 to develop a predictive logistic regression model for adult sex determination. We measured 433 adult birds of which 80% (n = 346) were randomly chosen to build potential models. Our best model included the variable estimate bill depth, which was found to be larger in males and correctly classified 80% of the birds. We validated the model with the remaining 20% of measurements (n = 87) and correctly identified the sex of 85% of the birds. Because this model incorporated roadrunners from across their range, it provides an easy, inexpensive, accurate, and field-relevant methodology for sex determination of adult roadrunners at the point of capture. © 2014 The Wildlife Society.

We studied Greater Roadrunners' (Geococcyx californianus) habitat use during spring and summer of 2011 in the Red Rolling Plains of west Texas. We captured 10 roadrunners (one male and nine females) and fitted each with a 10-g backpack style radio-transmitter. Roadrunners were relocated 2–4 times per week from February–August. We used these data to build a logistic regression model to better understand the vegetative and topographic features important to roadrunners during the nesting season. The initial data set consisted of 30 random and 30 used locations. The best model showed both percent rock and percent litter to be higher at used locations and correctly classified 88% of the sites. Evaluation of the model with an additional 30 random and 30 used locations maintained significance of both the model and variables and correctly classified 83% of sites. Both variables were associated with the location's mesa ridge slopes. Litter dominated locations under shrubs on the ridge tops and slopes and ...

Degradation of coastal systems has led to increased impacts from hurricanes and storm surges and is of concern for coastal endemics species. Understanding the influence of disturbance on coastal populations like the endangered Lower Keys marsh rabbit (Sylvilagus palustris hefneri) is important to understanding long-term dynamics and for recovery planning. We evaluated the effect of disturbance on the rabbits by determining which patch, habitat, and landscape characteristics influenced habitat use following Hurricane Wilma. We determined patch-level occurrence 6–9 months prior to Hurricane Wilma, within 6 months following the hurricane, and 2 years after the storm to quantify rates of patch abandonment and recurrence. We observed high patch abandonment (37.5% of used patches) 6 months after Hurricane Wilma and low rates of recurrence (38.1% of abandoned patches) 2 years after the storm, an indication that this storm further threatened marsh rabbit viability. We found the proportion of salt-tolerant (e.g., mangroves and scrub mangroves) and salt-intolerant (e.g., freshwater wetlands) vegetation within LKMR patches were negatively and positively correlated with probability of patch abandonment, respectively. We found patch size and the number of used patches surrounding abandoned patches were positively correlated with probability of recurrence. We suggest habitat use following this hurricane was driven by the differential response of non-primary habitats to saline overwash and habitat loss from past development that reduced the size and number of local populations. Our findings demonstrate habitat use studies should be conducted following disturbance and should incorporate on-going effects of development and climate change.

Deer–vehicle collisions (DVCs) are the primary source of mortality for the endangered Florida Key deer (Odocoileus virginianus clavium). Of these collisions, >50% occur on United States Highway 1 (US 1), the primary roadway connecting the islands in the Florida Keys, USA. The DVCs on the 5.6-km section of US 1 on Big Pine Key are responsible for approximately 26% of annual Key deer mortality, but extensive urban development along this highway segment complicates efforts to reduce DVCs using traditional methods (e.g., fencing, underpasses). In 2002, a continuous 2.6-km system of 2.4-m fencing, 2 underpasses, and 4 experimental deer guards was completed. We evaluated the long-term effectiveness of these highway improvements in reducing DVCs within an urban landscape. Deer used the underpasses all 7 postconstruction years (2003–2009) with dramatic increases in use over the course of the project. Roadway fencing largely eliminated deer intrusion onto the fenced area of US 1. Although well-maintained fencing effectively restricted deer movement onto the fenced section of US 1 (73–100% decline), other sections of US 1 experienced increases in DVCs. Overall, highway improvements along the US 1 corridor were effective in reducing Key deer mortality over the long-term. The success of deer guards in preventing deer access into the fenced section of US 1 supported the feasibility of implementing similar wildlife exclusion projects in other urban areas. © 2011 The Wildlife Society.

Conservation areas in tropical forests protect the most diverse and threatened ecosystems on the planet. In the Amazon, ungulates are important determinants of forest structure and plant diversity, as well as being a resource for rural communities. Using occupancy-based methods, we estimated the occurrence of white-lipped peccary Tayassu pecari, collared peccary Pecari tajacu, lowland tapir Tapirus terrestris and red brocket deer Mazama americana in and around protected areas reserve in Tambopata, Peru, to evaluate how different management designation, anthropogenic influences and habitat type influenced the occurrence of each species. We used a combination of track surveys (n=258) and camera surveys (n=256) to estimate ungulate presence at 55 sites in a national reserve, a native community and adjacent buffer areas from May 2008 to March 2009. We found that prediction of the occurrence of white-lipped peccary, lowland tapir and red brocket deer was best accomplished using travel time from the nearest city (a measure of an area's accessibility). The occurrence of ungulates differed little between buffer and reserves, but community lands managed by indigenous peoples showed reduced probabilities of ungulate occurrence. Our results indicate that passive protection afforded by inaccessibility might be an effective management strategy for this region; however, we doubt that this is tenable as a long-term solution.

The Lower Keys marsh rabbit (LKMR, Sylvilagus palustris hefneri), a marsh rabbit subspecies endemic to the Lower Keys, Florida was protected in 1990, however, populations continue to decline despite recovery efforts. We hypothesized on-going habitat loss and fragmentation due to succession and hardwood encroachment has lead to increased edge, reduced habitat quality, and increased activity by native raccoons (Procyon lotor). These factors reduce the suitability of patches in a later successional state, thus threatening LKMR recovery and metapopulation persistence. We surveyed 150 LKMR patches in 2008, tallying adult and juvenile rabbit pellets, estimating measures of habitat succession and quality (woody and herbaceous ground cover, distribution of herbaceous species) and recording raccoon activity (number of raccoon signs). We calculated patch edge (patch shape index) using ArcGIS. We evaluated the relationship between patch and habitat attributes and LKMR using regression analysis and model selection. We found both adult and juvenile LKMR pellet counts were lower in patches with higher shape indices and higher in patches with greater occurrence of bunchgrasses and forbs. We also found adult LKMR pellet counts were lower in patches with higher raccoon activity. Our results suggest patch edge, habitat succession and quality, and raccoons pose a threat to the persistence and recovery of LKMR populations. Recovery efforts should focus on reducing these trends through habitat management and raccoon removal implemented in carefully controlled experiments with proper monitoring. Measures of patch and habitat attributes important to LKMR should be incorporated into long-term metapopulation monitoring and used to evaluate recovery actions. Published by Elsevier Ltd.

We used nucleotide sequence data from a mitochondrial DNA fragment to characterize variation within the endangered Lower Keys marsh rabbit (Sylvilagus palustris hefneri). We observed 5 unique mitochondrial haplotypes across different sampling sites in the Lower Florida Keys, USA. Based on the frequency of these haplotypes at different geographic locations and relationships among haplotypes, we observed 2 distinct clades or groups of sampling sites (western and eastern clades). These 2 groups showed low levels of gene flow. Regardless of their origin, marsh rabbits from the Lower Florida Keys can be separated into 2 genetically distinct management units, which should be considered prior to implementation of translocations as a means of offsetting recent population declines.

Lesser prairie-chickens Tympanuchus pallidicinctus have declined throughout their range because of loss or fragmentation of habitat from conversion of native prairie to agricultural cropland, exacerbated by overgrazing and drought. We used data from radio-marked lesser prairie-chickens to determine whether differences in survival existed between populations occurring in two areas dominated by different vegetation types (sand sagebrush Artemisia filifolia vs shinnery oak Quercus havardii) in the Texas Panhandle from 2001 through 2005. We used a model-selection approach to evaluate potential generalities in lesser prairie-chicken survival. Our results indicated that survival of lesser prairie-chickens differed between breeding and non-breeding periods, and between study populations. We estimated annual survival of lesser prairie-chickens at 0.52 (95% CI: 0.32-0.71) in the sand sagebrush and 0.31 (95% CI: 0.12-0.58) in the shinnery oak vegetation type. Our results suggest that demographic differences in lesser prairiechicken within sand sagebrush and shinnery oak vegetation types throughout the Texas Panhandle should be evaluated, especially during the breeding season. Based on our results, higher mortality of birds during the breeding season illustrates the need to manage for vegetation components such as sand sagebrush and residual bunchgrasses as opposed to shinnery oak such that potential breeding season mortality may be lessened.

Many rangelands in the southwestern United States provide quality habitat for Northern Bobwhites (Colinus virginianus). These same habitats are frequently managed for livestock production and thus are subjected to various brush management practices that are meant to enhance forage production. Bobwhites rely on woody cover for food, thermal and loafing cover, and protection from avian predators. Implementing brush management practices that reflect bobwhite requirements is important for managing usable space and viable populations. We described the struc- tural vegetative characteristics associated with bobwhite locations and random locations on native rangelands in the upper Rolling Plains of Texas that are dominated by honey mesquite (Prosopis glandulosa) and managed with aerial her- bicide and prescribed fire. We also used binary logistic regression to model habitat selection; the initial model was built using 67% of the data (n = 179 used-random paired points) and then validated using the remaining 33% of the data (n = 88 used-random paired points). Locations used by bobwhites had significantly larger mean values of percent brush canopy cover, visual obstruction, and angle of obstruction than did random locations; random locations had a greater mean value of percent bare ground than locations used by bobwhites. The resulting logistic regression model contained only the angle of obstruction; the model had an 80% probability of correctly classifying used and random locations based on the area under the receiver operating curve (ROC). The model maintained a high classification probability when applied to the smaller validation data set, with an area under the ROC of 0.78.

Surface-mined land reclamation creates grass and shrub lands that provide important wildlife habitat, particularly for disturbance-dependent birds. Declines in disturbance-dependent birds have been observed for 30 years, emphasizing the importance of proper reclamation strategies. Understanding the influence of spatial factors on nesting ecology of avian populations can improve restoration strategies on reclaimed mines. We evaluated the influence of spatial factors on nest site selection, nest success, and nest parasitism of dickcissels (Spiza americana) on two sites reclaimed as wildlife habitat on the Big Brown Mine, Freestone County, Texas, in 2002–2003. We found 119 nests, 14 of which were parasitized by the brown-headed cowbird (Molothrus ater). Dickcissels were more likely to select nest sites farther from riparian areas and closer to brush-encroached areas. Nest success was not clearly explained by one or few variables. Parasitism was more likely to occur near riparian areas and roads. For these reasons, we suggest the establishment of larger wildlife habitat blocks, which would provide more field-interior habitat for dickcissels and similar species.

In order to address endangered Florida Key deer Odocoileus virginianus clavium vehicle collisions along a 5.6-km segment of United States Highway 1 (US 1), the Florida Department of Transportation (FDOT) constructed a 2.6-km long system of fencing, deer guards and two underpasses to exclude deer from roadway. The US 1 project was completed in 2002 for the purpose of minimizing Key deer mortality and maintaining deer permeability through the Big Pine Key (BPK) corridor, Florida, USA. We evaluated the potential impact of these modifications to Key deer movements by comparing 1) annual ranges and movements of Key deer pre- (January 1998 - December 2000) and post-construction (February 2003 - January 2004), 2) deer-vehicle collisions on US 1 pre- and post-construction, and 3) underpass use post-construction. Mean female and male annual ranges and core areas did not change (P>0.05) between pre- and post-construction. Deer movements within the US 1 project area were comparable pre- (six of 23 radio-col...

Status assessment of endangered Florida Key deer (Odocoileus virginianus clavium) is currently limited by a paucity of information regarding population estimates for outer islands, which collectively comprise approximately 70% of potential habitat within the Key deer range. Practical limitations and financial considerations render traditional survey techniques impractical for application on remote outer islands. Our objective was to evaluate the utility of infrared-triggered cameras to estimate Key deer abundance on outer islands. We used digital infrared-triggered cameras and mark–resight methods to estimate Key deer abundance on 20 outer islands. Abundance estimates for primary subpopulations ranged from 15 to 16 for Howe Key, 5 to 10 for Knockemdown complex, and 13 to 17 for Little Pine Key. Other island complexes such as Ramrod Key, Water Key, and Annette complex maintain only small subpopulations (i.e., ≤5 individuals) and other previously inhabited island complexes (e.g., Johnson complex an...

Approximately 26% of annual mortality for the endangered Florida Key deer (Odocoileus virginianus clavium) occurs as deer-vehicle collisions (DVCs) on the 5.6-km section of United States Highway 1 (US 1) on Big Pine Key (BPK), but extensive urban development adjacent to sections of US 1 complicates efforts to reduce DVCs. Our objective was to evaluate the effectiveness of the US 1 Project (continuous 2.6-km system of 2.4-m fencing, 2 underpasses, and 4 experimental deer guards constructed on US 1 on BPK) in reducing DVCs along US 1. Deer used the underpasses all 3 postproject years (2003-2005); however, we observed higher underpass use in 2004 and 2005 compared to 2003. Exclusion fencing reduced deer intrusions onto the fenced section of US 1 during the 3-year period (2003, n = 7 deer; 2004, n = 4; 2005, n = 12). With a reduction of deer intrusions onto this section of US 1, DVCs decreased in the fenced area by 73-100%; however, US 1 DVCs within the unfenced sections of US 1 also increased (40%) as expected. In controlling for effects of increasing deer density and traffic volume, study results suggest that highway improvements have decreased the net risk of DVCs along US 1, which indicates that use of deer fencing, deer guards, and underpasses is applicable in other urban communities experiencing unacceptable levels of DVCs.

A number of studies on mammalian species that have adapted to urban areas suggest survival may be higher for urban populations than rural populations. We examined differences in fatalities between an urban and rural population of fox squirrels (Sciurus niger). We radiocollared (n = 50 rural, n = 78 urban) fox squirrels during approximately 2 years. We found monthly survival of rural fox squirrels (Ŝ = 0.936) was lower than urban fox squirrels (Ŝ = 0.976) over the same 12-month period. Nonetheless, when comparing a 24-month period of survival data on urban squirrels with an 18-month period on the rural squirrels (periods overlapped for 12 months), survival rates were more similar between urban (Ŝ = 0.938) and rural squirrels (Ŝ = 0.945). Our data suggest that sex and season may influence survival of urban squirrels and not rural squirrels. We also found that cause of fatalities differed between the urban and rural squirrels, with >60% of fatalities on the rural site caused by predation. In contrast, 60% of urban fox squirrel fatalities were caused by motor vehicle collisions. This study illustrates the need to advance our ability to understand, predict, and mitigate effects of urbanization on wildlife resources.

Tree squirrels are one of the most familiar mammals found in urban areas and are considered both desirable around homes and, conversely, a pest. We examined fox squirrel (Sciurus niger) habitat use in inner city and suburban areas using radiotelemetry. We estimated habitat selection ratios at differing scales by season and fox squirrel activity. Telemetry data suggests that during periods of inactivity radiocollared fox squirrels (n = 82) selected 1) areas with greater tree canopy, 2) live oaks (Quercus fusiromis and Q. virginiana), and 3) trees with larger diameters and canopies. When inactive during the winter and spring, fox squirrels also preferred, within their core areas, to use the inside of buildings, and during periods of activity in the autumn and spring, fox squirrels preferred grassy areas. During periods of activity, fox squirrels avoided using pavement but did not exclude it from their core-area movements. Fox squirrels' ability to use buildings and to tolerate pavement in core-area...

Rapid human population growth and urbanization have had a negative impact on species biodiversity. As competition for resources between man and wildlife continues, it is important to understand the effects of urbanization on species. Endangered Key deer (Odocoileus virginianus clavium) are endemic to the Florida Keys which have undergone rapid human population growth and development over the past 30 years. Our study objectives were to evaluate the impacts of urban development on Key deer habitat use, population dynamics, behavior, and body mass. We used data from two comprehensive studies on Key deer spanning 30 years to evaluate these changes. Our results suggest that Key deer have become more urbanized, using urban areas more today than they did 30 years ago. Contrary to our predictions, survival was higher for more urban deer than for less urban deer. Problems still exist with mortality factors heavily impacting some portions of the deer population including lower survival associated with less urban male deer. Analysis of Key deer body mass also was converse to our predictions as deer weights appear to have increased over time. Collectively, our results suggest that over the past 30 years Key deer have become more urbanized and that deer plasticity has allowed them to adapt and persist in an urbanizing environment. However, the future ability of Key deer to persist in an environment with continued urban development is unknown. At some threshold, urban development would become unsustainable and unlike other forms of habitat change or environmental disturbances, urban development is in most cases irreversible requiring careful planning in habitat conservation strategies.

We radio-collared and tracked 16 (10 female, 6 male) Neotoma floridana smalli (Key Largo woodrats) from March–November 2002 and recorded a total of 631 locations. The average monthly ranges of individual male and female woodrats were 4756 (95% CI = 2376–7136) m2 and 2051 (95% CI = 1091–3011) m2, respectively. We found male and female ranges to be significantly different (P = 0.032). Female ranges varied with season (P = 0.032), while male ranges did not (P = 0.567). Spring (P = 0.033) and summer (P = 0.019) ranges were significantly different between sexes. At two spatial scales, Key Largo woodrats showed a preference for young habitat with selection ratios of 6.3 and 6.7. Six female ranges overlapped an average of 49% and 2 males overlapped an average of 8%. No woodrats were recorded crossing a major road. Study results suggest that N. f. smalli prefer early succession hammock, male woodrats should be introduced separately, and a major road is a barrier to woodrat movements.

High white-tailed deer (Odocoileus virginianus) densities in urban areas typically result in human–wildlife conflicts (e.g., deer–vehicle collisions, transmission of disease to humans, and vegetation damage). Controlling deer densities via fertility control generally is more acceptable than lethal removal in many urban areas and can reduce conflicts by stabilizing deer numbers. Contraceptive vaccines that use PZP (porcine zona pellucida) proteins as antigens have been used for many years and generally are regarded as safe and effective. Side effects of immunocontraception may be repeated estruses, an extension of the breeding season, and increased movements and ranges of immunized deer. We evaluated the effects of SpayVac™, a long-lasting, single-dose PZP vaccine on ranges and movements of female white-tailed deer at the Lyndon B. Johnson Space Center near Houston, Texas, USA. We captured, treated, and radiomarked 38 female deer with SpayVac (treatment) and injected 11 deer with a placebo (contro...

The endangered Lower Keys marsh rabbit (LKMR; Sylvilagus palustris hefneri) exists as a metapopulation in patches of wetland habitat in the Lower Florida Keys, USA. The recovery plan for the LKMR recommends reintroducing rabbits to unoccupied but potentially suitable patches. The effectiveness of such reintroductions has not been evaluated. We translocated 12 and 7 rabbits fitted with radiotransmitters to patches of apparently suitable vegetation on Little Pine and Water Key during 2002 and 2004, respectively. Our radiotelemetry-based study monitored survival, site fidelity, and reproduction. We observed high survival (81% of known-fate rabbits on Little Pine and 100% on Water Key), fidelity to release sites (mean distance from release sites

The aim of the present study was to estimate changes in plant species composition in sev- eral forest communities caused by changes in endangered Key deer (Odocoileus virginianus clavium) densities in the National Key Deer Refuge in the lower Florida Keys. Baseline vegetation quadrats from a 1990 study were resampled in 2002 (the present study) in buttonwood transition, hardwood hammock, and mangrove wetland communities (all deer habitat) on 12 islands with low, medium, and high Key deer densities. On islands with high Key deer densities (>17 deer km -2 ), the relative densities of pre- ferred plant species 1.2 m tall (midstory/canopy) also significantly decreased in hammock on islands with high deer density, suggesting that heavy browsing is deterring plant growth/recruitment, thus already affecting regeneration of certain plant species into the midstory/canopy tiers. Plant species richness did not vary significantly between 1990 and 2002 for islands with high deer densities, but tended to increase slightly on islands with low deer density in but- tonwood and hammock communities. Evidence from this study suggests that high densities of Key deer influence plant species composition on certain islands. We suggest that management plans for Key deer should incorporate both species protection components and population control techniques dependent on deer density-island associations.

Metapopulation dynamics of species that occur in patchy or island subpopulations are an important consideration in the conservation of endangered species. Key deer ( Odocoileus virginianus clavium ) are endemic to the Florida Keys and occur on 11 island-complexes in the Lower Keys from Big Pine Key to Sugarloaf Key. While deer numbers have increased notably, the majority of the population occurs on two of the islands, Big Pine and No Name Keys. Deer dispersal between islands is possible due to short distances between islands and shallow water. Key deer have been documented to actively disperse between islands but at very low rates (11% males, 3% females). However, increased population densities could possibly increase dispersal rates as island populations on Big Pine and No Name Keys approach carrying capacity. We examined the probability of deer colonization of peripheral islands using a sex- and stage-structured metapopulation model. Our objectives were to (1) evaluate the effects of distance and dispersal rate on Key deer island subpopulations and (2) estimate the probability of Key deer colonizing surrounding islands with viable populations. Results suggest that over the next 20 years, the Key deer population could colonize 6 of the 11 island-complexes with viable populations. However, of the remaining five islands, three lack the resources to support a minimum viable population, and while Cudjoe and Sugarloaf Keys have the potential to support >200 deer each, they are not projected to increase to above 50 deer by 2021 regardless of dispersal rate due to distance from source population.

Over the last two decades, declines in trap success, stick-nest density and population density estimates have fueled concerns that the federally endangered Key Largo woodrat (KLWR, Neotoma floridana smalli) population is declining. Information on the current population status and habitat selection of KLWR is needed in the recovery of this population. We trapped on 60 (1-ha) randomly-placed grids (20 grids in each of three hardwood hammock age-classes). Grids were trapped from March–September 2002 and April–August 2004. Population estimates for the two trapping periods were 106 (95% ci 30–182) and 40 (95% ci 5–104) individuals, respectively. Greater than 80% of all KLWRs captures occurred in the young hammock age-classes (disturbed after 1971). Young hammocks were characterized by a more open canopy, smaller overstory trees, fewer logs, greater dispersion of overstory trees and a different species composition than old and medium age hammocks (P < 0.024). Contrary to previous research, KLWRs were f...

Wildlife managers require reliable, cost-effective, and accurate methods for conducting population surveys in making wildlife management decisions. Traditional methods such as spotlight counts, drive counts, strip counts (aerial, thermal, infrared) and mark–recapture techniques can be expensive, labor-intensive, or limited to habitats with high visibility. Convenience sampling designs are often used to circumvent these problems, creating the potential for unknown bias in survey results. Infrared-triggered cameras (ITCs) are a rapidly developing technology that may provide a viable alternative to wildlife managers because they can be economically used with alternative sampling designs. We evaluated population-density estimates from unbaited ITCs and road surveys for the endangered Florida Key deer (Odocoileus virginianus clavium) on No Name Key, Florida, USA (461-ha island). Road surveys (n = 253) were conducted along a standardized 4-km route each week at sunrise (n = 90), sunset (n = 93), and ni...

Drift fences, often in conjunction with pitfall or funnel traps, commonly are used to capture amphibians and reptiles (Gibbons and Semlitsch 1981, Corn 1994), small mammals (Kirkland and Sheppard 1994), and fledgling birds (Nettleship 1969). Gibbons and Semlitsch (1981) noted the incidental capture of eastern cottontails (Sylvilagus floridanus) using drift fences with pitfall traps. However, with the exception of Ludeman (1954), who suggested drift fences as a means to prevent porcupines (Erethizon spp.) from damaging trees, we are unaware of drift fences being used for the purpose of capturing of medium-sized mammals. Listed as federally endangered in 1990, the Lower Keys marsh rabbit (hereafter marsh rabbit; S. palustris hefneri) exists as a metapopulation in 102 patches of wetland habitat in Florida's Lower Keys (United States Fish and Wildlife Service 1990, Forys and Humphrey 1996, Faulhaber 2003). In areas with thick grasses (e.g., gulf cord grass [Spartina spartinae] and saltmeadow cordgrass [Spartina patens]), the conventional method for trapping marsh rabbits consists of placing nonbaited 2-door live traps in tunnels and corridors through the vegetation (Forys 1995, Faulhaber 2003). However, habitats with low or sparse herbaceous growth, such as saltmarshes dominated by seashore dropseed (Sporobolus virginicus) and some areas within sawgrass (Cladium jamaicense) marshes, did not provide the vegetation structure required for this method. Trapping alternatives included use of baits or scent (e.g., domestic rabbit urine); however, Forys (1995) and Faulhaber (2003) were unable to find a suitable bait to lure marsh rabbits into traps, and some baits posed the additional problem of attracting raccoons (Procyon lotor). Domestic rabbit urine could not be used as it may have posed a disease problem to this endangered species. Here we describe the use of drift fences in conjunction with 2-door live traps to capture marsh rabbits in habitats where conventional trapping methods were unsuccessful or unfeasible.

We evaluated the effectiveness of supplemental stockings being proposed in the recovery of the federally endangered Key Largo woodrat (KLWR, Neotoma floridana smalli) using a stage-based, stochastic model. Supplemental stockings were evaluated with a population model using current trapping and telemetry data along with published and unpublished KLWR data. Model simulations predicted the KLWR had >70% probability of terminal extinction over the next 10 years even with the use of supplemental annual stockings. Supplemental stockings of KLWRs (⩽20 females) appear to delay the extinction of the species, but negative population trajectories accelerated after stockings cease. Model results illustrated the importance of determining limiting factors on the population prior to the use of supplemental stockings as a recovery option for this endangered woodrat population.

Wildlife extinction represents the ultimate failure of wildlife conservation. It has many causes, some of them natural, but is increasingly tied to anthropogenic factors. Wildlife loss via domestication, however, is rarely considered. We evaluated the potential for inadvertent domestication of wildlife by determining the effect of feeding and watering on Key deer (Odocoileus virginianus clavium) density, group size, and distribution. Key deer sightings were significantly higher in areas (42 ha) surrounding the households that provided food and water (0.18 deer/m; n= 8) than in randomly selected areas (0.03 deer/m; t = 3.82, 14 df , p = 0.002). Average distance to a household providing food and water decreased logistically as group size increased, and large groups (>2 individuals each) were observed more frequently in areas where food and water were provided (27.5%) than in the randomly selected areas (7.5%). The incidence of large groups outside feeding areas (7.5%), however, was similar to the incidence of large groups during early urbanization (5.1%; 1968- 1973). Our results suggest illegal feeding caused changes in density, group size, and distribution indicative of domestication. Because fresh water and food were primary selective pressures for Key deer before illegal feeding and watering, genetic changes may occur in the future. For those who value "wildness" in wildlife, domestication of wildlife species is a serious problem that must be addressed.

The relationship between population density and range size has long been debated. While many studies have documented varying responses in range size to changes in pop- ulation densities, most have been the result of experimental manipulation. We examined the effects of long-term density changes in Florida Key deer (Odocoileus virginianus clav- ium) on range and core-area sizes. We radiocollared Key deer as part of 2 separate research projects conducted December 1968-June 1972, and January 1998-December 2001. We used a total of 96 (females, n = 62; males, n = 34) and 163 (females, n = 88; males, n=75) radiocollared Key deer to calculate annual and seasonal ranges and core areas, respectively. Season and age were not important factors in describing ranges and core areas of Key deer, while sex and period (early vs. current study) were important. On average, male annual ranges (x - = 221 ha, current; x - = 388 ha, early) were greater than female annual ranges (x - =42 ha, current; x - =101 ha, early), which might explain higher male mortality due to roadkills. Early ranges and core areas were greater (≈2x) than cur- rent ranges and core areas. We suggest that increased deer densities may have resulted in a decrease in Key deer ranges. Other factors influencing changes in Key deer ranges included increased habitat quality and Key deer domestication over the last 30 years.

The introduction of pen-reared Attwater's prairie-chickens (APC, Tympanuchus cupido attwateri) into the wild to supplement existing populations has met with marginal success. Flight characteristics, predator avoidance behavior, and rearing methods may contribute to post-release mortality of pen-reared birds. We compared flight characteristics and predator avoidance behaviors of pen-reared APC released onto the Attwater Prairie Chicken National Wildlife Refuge with those of a sister subspecies, wild greater prairie-chickens (GPC, T. c. pinnatus) in Minnesota and Kansas. There was no difference (P = 0.134) in flight speed of pen-reared APC and wild GPC. However, wild GPC flew further (P

Increasing white-tailed deer (Odocoileus virginianus) numbers in urban environments is a management problem for both natural resource agencies and urban residents because of economic (e.g., deer-vehicle collisions) and ecological (e.g., ornamental and native vegetation damage) issues associated with deer "overabundance." Reducing deer num- bers using nonlethal control procedures often requires the safe (i.e., low mortality) cap- ture of urban white-tailed deer. We describe the use of a portable drive-net to capture urban white-tailed deer. We attached nylon drive-nets of various lengths, heights, and mesh sizes to an anchor (e.g., fencepost, T-post, tree) and placed them neatly on the ground. Persons on foot would drive deer toward the drive-net while one person would pull the net vertically to coincide with deer arrival. From June 1998-October 2003, we captured 76 white-tailed deer (25 M, 51 F) in Texas and Florida using the portable drive- net. No deer mortalities were recorded, and

Urban development in the Florida Keys, USA, mandates an understanding of how habitat requirements for Florida Key deer (Odocoileus virginianus clavium) interact with vegetation changes caused by development. Our study objectives were to (1) determine Key deer habitat use at different spatial scales, (2) evaluate vegetation changes and identify vegetation types most threatened by development, and (3) provide guidelines to direct land acquisition programs in the future. We identified 6 vegetation types: pineland, hammock, developed, freshwater marsh, buttonwood, and mangrove. Key deer (n = 180; 84 F, 96 M) preferred upland vegetation types (>1 m above mean sea level; pineland, hammock, developed) and avoided tidal or lower-elevation areas (

The endangered Florida Key deer (Odocoileus virginianus clavium) is endemic to the Florida Keys, Florida, USA, with Big Pine Key (BPK) supporting most (approx 60%) of the population. Habitat loss and fragmentation have altered the amount of available habitat, creating areas of varying suitability; north BPK (NBPK) is believed to contain more optimal habitat than south BPK (SBPK), which is more developed and fragmented. We evaluated the source–sink dynamics of Key deer using a sex- and stage-structured, stochastic matrix model. Model results indicated that the NBPK population of Key deer was increasing (λ = 1.02), whereas the SBPK population was decreasing (λ = 0.87). Without dispersal from the north, the SBPK population has a 97% probability of falling below 25 individuals (quasi-extinction threshold) in the next 20 years. The higher risk to Key deer in SBPK can be explained by relative habitat-quality differences between the 2 areas. House density, amount of roads, number of fences, and amount o...

With decreased illegal hunting and better habitat conservation, the Florida Key deer (Odocoileus virginianus clavium) population grew from an estimated 25–50 animals in the late 1940s to approximately 200 animals on Big Pine and No Name keys, Florida, USA, by 1971, the last official survey. U.S. Fish and Wildlife Service (USFWS) trend data indicate that the deer population continued to increase after 1971; however, current deer density estimates are necessary for the proposed reclassification of the Key deer from endangered to threatened. Our study objectives were to (1) obtain current population estimates of Florida Key deer and compare these to historical estimates, (2) evaluate survey methods (USFWS mortality and deer counts) in detecting changes in population trends, and (3) outline a protocol for future monitoring. Road counts (n = 889) were conducted from January 1971 to December 1971 and January 1976 to December 2001 on Big Pine and No Name keys. From mark–recapture data, we estimated that...

Assuming that a finite biosphere can support infinite development seems logically inde- fensible, yet the concept of sustainable development has become a dominant conserva- tion paradigm. The story of the endangered Florida Key deer (Odocoileus virginianus clavium) appears to support the legitimacy of sustainable development because Key deer numbers have increased 240% since 1970 while at the same time human numbers in their habitat increased nearly 10-fold. Because fawn mortality is considered the primary density-dependent factor regulating cervid populations as they approach K-carrying capacity, we hypothesized that changes in fawn demographics could elucidate the falla- cy in assuming that development was sustainable on Big Pine Key. We determined and compared survival and range sizes for Key deer fawns between 1968-1972 (early urban development) and 1998-2002 (post-urban development). Fawn ranges (95% probability area, 149 to 33 ha) and core areas (50% probability area, 25 to 6 ha) decreased during this period of development while 6-month survival increased (0.47 to 0.96). All fawn mortality was due to anthropogenic causes; the positive relationship between fawn sur- vival and development may be a function of isolating fawns from anthropogenic mortal- ity. If this is true, the relationship is not sustainable because as ranges continue to shrink, they eventually will lack sufficient resources to support a fawn.

Fetal sex ratios (FSRs) have important implications for managing small isolated populations. Mean male-biased FSRs ranging from 2.67:1 to 1:1 have been reported for the endangered Florida Key deer (Odocoileus virginianus clavium ). Several general hypotheses have been proposed that describe the manner in which FSR may vary within a deer population over time: (1) tendency to equalize the sex ratio by producing the minority sex, (2) poor body condition results in more males, and (3) excellent body condition results in more males. Our objective was to evaluate implications of FSR for Key deer as suggested by these hypotheses. Because of their small numbers and geographic isolation, the issue of FSR is important for predicting response of Key deer to management actions. We developed nine alternative deterministic models representing combinations of three mean or median FSRs that have been hypothesized for Key deer and the three hypothesized mechanisms of FSR variation. With each model, we simulated Key deer demographics and compared predictions with actual survey data (1971–2000). The model with the best prediction was based on a median FSR of 1.45:1, and the FSR variation within the survey data best supported the hypothesis that poor body condition would result in more males. Our results indicate the most commonly cited FSR (2.67:1) for Florida Key deer is inaccurate, probably due to small sample size. We conclude that FSR variation has the potential to shape the response of endangered populations to disturbance. © 2003 Elsevier Science B.V. All rights reserved.