Endangered Florida Key Deer Research Articles

Assessing hurricane impact on vegetation and endangered deer habitat using airborne lidar and multispectral images

In the lower Florida Keys, the endangered Florida Key deer and numerous other wildlife species inhabit a vulnerable island environment susceptible to storm surges and rising seawater due to low elevation and flat terrain. Timely and reliable assessment of vegetation damage from natural disasters, such as Hurricane Irma, is crucial for effective habitat management. The study’s overall objective is to examine Hurricane Irma’s impact on vegetation on No Name Key, Florida, using remote sensing. The study relates the area change in vegetation obtained from remote sensing analysis to Florida Key deer population changes following the storm. The methodology involved performing a thematic change detection analysis using the following data sources: (1) aerial multispectral images (for pre- and post-Hurricane), (2) airborne lidar data (for pre- and post-Hurricane), (3) an existing vegetation map, and (4) soil data. A Support Vector Machine (SVM) image classification algorithm was applied to pre- and post-storm input image stacks to create pre- and post-Hurricane Irma vegetation maps. We were then able to obtain the area change information (for various vegetation categories) by performing the change detection analysis of the 2 SVM-classified images. The differences in areas following the storm were calculated for 7 affected vegetation types. Using the area change information following Hurricane Irma, we estimated the number of deer supported by the storm-affected vegetation. These estimated deer numbers, based on the area differences in post-Hurricane Irma vegetation types, were compared to observed deer numbers collected during the post-Hurricane Irma Texas A&M Natural Resources Institute (NRI) deer field survey. The results showed the following: mangroves had the largest negative area changes (area loss), followed by pinelands, hardwoods/hammocks, developed areas, and buttonwoods. Freshwater marshes had the largest positive area changes (area gain). The deer's preferred vegetation areas had decreased post-Hurricane Irma, resulting in a reduced deer population compared to pre-storm numbers. The predicted number of the Key deer post-Hurricane Irma fell within a 95% confidence interval of the observed deer population from the post-storm field survey. The study findings and techniques could be applied to study climate change impact, especially sea level rise. This methodology can be valuable in assessing the impact of storms on other wildlife species in similar environments. The applications and methodology are especially relevant considering the increasing frequency and intensity of storm surges and the accelerating rate of sea level rise.

Modeling the impact of sea level rise on endangered deer habitat

Numerous unique flora and fauna inhabit the Lower Florida Keys, including the endangered Florida Key deer, found nowhere else. In this vulnerable habitat of flat islands with low elevation, accelerated sea level rise poses a threat. Predicting the impact of sea level rise on vegetation and wildlife is crucial. This study used 5 Intergovernmental Panel on Climate Change (IPCC) sea level rise scenarios to assess their effects on No Name Key, Florida. The goal was to estimate changes in the Florida Key deer population relative to sea level rise using a lidar-derived elevation data and a vegetation map. The method used 2 cases to model the sea level rise impact. In Case 1, total non-submerged area at current sea level was determined. Using 5 IPCC scenarios, a new total non-submerged land area was estimated, and deer numbers were predicted for each scenario. In Case 2, upward migration of coastal vegetation combined with the coastal squeeze process was modeled. A distinct elevation range for each vegetation type at the current sea level was determined. Vegetation ranges were redistributed based on respective elevation ranges in the sea level rise scenarios. Areas for each vegetation type were recalculated, and Key deer numbers were estimated for each sea level rise scenario. Results under the worst emission scenario showed the following: (1) for case 1, the land area was reduced to 30 % of the current land area, corresponding to having about 27 deer, and (2) for case 2, the land area was reduced to 70 % of the current land area, having about 54 deer on No Name Key. The results indicated reduced non-submerged land area and less upland vegetation, particularly hardwoods/hammocks, by the year 2100. As less land area is available, a decline in Key deer population is expected as sea levels rise. Since Key deer favor upland vegetation, habitat affected by sea level rise will likely support a smaller deer population. The findings emphasize the need for precise, timely predictions of sea level rise impacts and long-term conservation strategies. Specifically designed measures are required to protect and maintain endangered wildlife, such as the Florida Key deer, residing on these vulnerable islands.

Prion Protein Gene (PRNP) Sequences Suggest Differing Vulnerability to Chronic Wasting Disease for Florida Key Deer (Odocoileus virginianus clavium) and Columbian White-Tailed Deer (O. v. leucurus).

Chronic wasting disease (CWD) is a fatal, highly transmissible spongiform encephalopathy caused by an infectious prion protein. CWD is spreading across North American cervids. Studies of the prion protein gene (PRNP) in white-tailed deer (WTD; Odocoileus virginianus) have identified non-synonymous substitutions associated with reduced CWD frequency. Because CWD is spreading rapidly geographically, it may impact cervids of conservation concern. Here, we examined the genetic vulnerability to CWD of 2 subspecies of WTD: the endangered Florida Key deer (O. v. clavium) and the threatened Columbian WTD (O. v. leucurus). In Key deer (n = 48), we identified 3 haplotypes formed by 5 polymorphisms, of which 2 were non-synonymous. The polymorphism c.574G>A, unique to Key deer (29 of 96 chromosomes), encodes a non-synonymous substitution from valine to isoleucine at codon 192. In 91 of 96 chromosomes, Key deer carried c.286G>A (G96S), previously associated with substantially reduced susceptibility to CWD. Key deer may be less genetically susceptible to CWD than many mainland WTD populations. In Columbian WTD (n = 13), 2 haplotypes separated by one synonymous substitution (c.438C>T) were identified. All of the Columbian WTD carried alleles that in other mainland populations are associated with relatively high susceptibility to CWD. While larger sampling is needed, future management plans should consider that Columbian WTD are likely to be genetically more vulnerable to CWD than many other WTD populations. Finally, we suggest that genetic vulnerability to CWD be assessed by sequencing PRNP across other endangered cervids, both wild and in captive breeding facilities.

Long‐term effectiveness of US 1 crossing project in reducing florida key deer mortality

AbstractDeer–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.

Ecology and management of deer in developed landscapes: An introduction

Ecology and management of deer in developed landscapes: An introduction

DISTRIBUTION OF MYCOBACTERIUM AVIUM SUBSPECIES PARATUBERCULOSIS IN THE LOWER FLORIDA KEYS

Johne's disease, a fatal and contagious gastrointestinal infection caused by Mycobacterium avium subsp. paratuberculosis (Map), was first diagnosed in an endangered Florida Key deer (Odocoileus virginianus clavium) in 1996 and later in six additional Key deer deaths from 1998 to 2004. We investigated the geographic distribution of Map in the Lower Florida Keys from February 2005 through May 2006 via collection of blood and fecal pellets from 51 live-captured deer, collection of 550 fecal samples from the ground, and by necropsies of 90 carcasses. Tissue and fecal samples also were submitted from 30 raccoons (Procyon lotor), three feral cats (Felis catus), an opossum (Didelphis virginiana), and a Lower Keys marsh rabbit (Sylvilagus palustris hefneri). Mycobacterium avium subsp. paratuberculosis was identified in 23 Key deer fecal samples collected from the ground, tissue samples from two clinically ill Key deer, and from the mesenteric lymph node of a raccoon. The results of this study indicate that Map persists in the Key deer population and environment at a low prevalence, but its distribution currently is limited to a relatively small geographic area within the range of Key deer.

Evaluation of the Efficacy of Florida Key Deer Translocations

Abstract: The endangered Florida Key deer (Odocoileus virginianus clavium) is endemic to the Lower Florida Keys. In recent years, habitat fragmentation and restricted dispersal have resulted in small, isolated herds on some islands. Recovery biologists proposed translocations to increase the island herds that had declined or remained low; however, efficacy of Key deer translocations had yet to be evaluated. Our objective was to evaluate survival, ranges, reproduction, and dispersal of translocated deer. During 2003–2005, we translocated 39 adult or yearling deer to Sugarloaf (approx. 19 km from trap site; 10 M, 14 F) and Cudjoe (approx. 15 km from trap site; 6 M, 9 F) keys. We kept deer in large, high‐fenced holding pens (Sugarloaf = 7.7 ha, Cudjoe = 10.7 ha) on the destination islands for 3–6 months (i.e., soft release). We observed low mortality (n = 6 mortalities) of translocated deer with average annual survival (S) of 0.796 for both sexes. We found translocated deer had larger seasonal ranges than did resident deer (i.e., those located on Big Pine and No Name keys). In evaluating effects of acclimation period on ranges and dispersal, we found no difference in 95% ranges or 50% core areas ≤4 month postrelease versus 4–8 months postrelease. We found, however, postrelease dispersal distances were dependent on time kept in pen. Only 2 of 39 (5%) translocated deer left the destination islands by the end of the study. With high survival and low dispersal indicating success, we credit soft release translocation in establishing deer herds on Sugarloaf and Cudjoe keys. Our data support translocations as an effective strategy for creating sustainable outer‐island Key deer herds.

Digital Versus Film-Based Remote Camera Systems in the Florida Keys

Remote-triggered cameras are an important tool in wildlife research and the increasing availability of digital camera technology can potentially provide researchers with additional options and benefits. We compared the performance and cost of a remote digital camera system (passive infrared) with 2 well-established remote film-based camera systems (1 passive, 1 active) in the Lower Florida Keys. During the approximately month-long study, we found that the digital system provided similar performance and potentially decreased cost compared to the film-based systems when monitoring the endangered Florida Key deer (Odocoileus virginianus clavium). Considering the benefits of passive digital camera systems (e.g., large photograph storage capacity, less equipment, easy photograph manipulation), comparable performance by the digital system to film-based systems provides motivation to consider this new and evolving technology in future wildlife research.

Florida Key deer Odocoileus virginianus clavium underpass use and movements along a highway corridor

Abstract 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...

Distribution and Abundance of Endangered Florida Key Deer on Outer Islands

ABSTRACT 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 and Summerland Key) no longer maintain subpopulations. Key deer abundance was well below estimated carrying capacities on all outer islands, with larger natural populations occurring closest to Big Pine Key. Our results suggest that camera‐based surveys offer a practical method to monitor abundance and population trends of Key deer on outer islands. Our study is the first to estimate Key deer abundance in these areas using technically structured model‐based methods and provides managers with current and baseline information regarding Key deer subpopulations.

Effects of US 1 Project on Florida Key Deer Mortality

ABSTRACT 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.

Comparison of Camera and Road Survey Estimates for White-Tailed Deer

Abstract 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...

SOURCE–SINK DYNAMICS OF FLORIDA KEY DEER ON BIG PINE KEY, FLORIDA

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 of development were all greater in SBPK. Collectively, study results indicate that SBPK can be described as an ecological sink with a nonviable population supplemented by deer dispersal from NBPK (source). Care should be taken to preserve the source population and its habitat. Thus, we propose limiting future development in NBPK (high-quality source habitat). The US 1 highway corridor project has the potential to decrease Key deer mortality due to vehicle collisions, and we recommend that future management goals continue to address mortality factors on SBPK (low-quality sink habitat).

Key deer fawn response to urbanization: is sustainable development possible?

Assuming that a finite biosphere can support infinite development seems logically indefensible, yet the concept of sustainable development has become a dominant conservation 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 fallacy 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 survival and development may be a function of isolating fawns from anthropogenic mortality. 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.

Implications of fetal sex ratio hypotheses in endangered populations: simulated dynamics of Florida Key deer, Florida, USA

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.

Cultural Conflict and the Endangered Florida Key Deer

Conflict regarding the conservation and preservation of natural resources is among the greatest challenges of the 21st century. Given that management of natural resources increasingly depends on securing cooperation of culturally diverse groups of people, it is important to understand how to secure that cooperation. Endangered species management on private lands both typifies and magnifies the environmental conflicts encountered by natural resource policy makers and managers. Using an ethnographic approach, we analyzed the conflict surrounding management of the endangered Florida Key deer (Odocoileus virginianus clavium) to explore how conflict and moral culture apply to natural resource policy formation and implementation. We found disputants on Big Pine Key divided into 2 moral cultures-1 grounded in stewardship and the other in private property rights. These moral cultures augmented the conflict by perpetuating divergent ethical perspectives and aspirations. The conflict then escalated through de-individualization, dehumanization, and demonization of those informed by the opposing moral culture. Finally, as typically occurs with serious conflicts, incompatible frames of reference created by the cultural divide not only prevented rapid de-escalation but promoted conflict-reinforcing mechanisms such as selective perception and judgment, moral exclusion, and rationalization, which led to communication breakdown and autistic hostility. Temporary solutions to superficial problems that were maladapted to conflicts involving moral culture did not ameliorate conditions and often exacerbated them. In emotionally charged decision-making venues, wildlife managers should take a proactive approach designed to encourage collaborative development of common ground among disputants. When conflicts reach a highly escalated state, as many inevitably will, their resolution will require meeting appropriate pre-negotiation conditions, then applying strategies that respond to both the level of escalation and the moral cultures involved in the particular conflict.