Effects of US 1 Project on Florida Key Deer Mortality

Transcription

1 Management and Conservation Article Effects of US 1 Project on Florida Key Deer Mortality ISRAEL D. PARKER, 1 Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA ANTHONY W. BRADEN, Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA ROEL R. LOPEZ, Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA NOVA J. SILVY, Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA DONALD S. DAVIS, Department of Veterinary Pathobiology, Texas A&M University, College Station, TX 77843, USA CATHERINE B. OWEN, Environmental Management Office, Florida Department of Transportation, Miami, FL 33172, USA 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 ( ); however, we observed higher underpass use in 2004 and 2005 compared to Exclusion fencing reduced deer intrusions onto the fenced section of US 1 during the 3-year period (2003, n ¼ 7 deer; 2004, n ¼ 4; 2005, n ¼ 12). With a reduction of deer intrusions onto this section of US 1, DVCs decreased in the fenced area by %; 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. (JOURNAL OF WILDLIFE MANAGEMENT 72(2): ; 2008) DOI: / KEY WORDS deer guards, deer vehicle collisions, Florida Key deer, Odocoileus virginianus clavium, underpasses, US 1 Project. Florida Key deer (Odocoileus virginianus clavium) are the smallest subspecies of white-tailed deer in the United States and occupy islands in the Lower Florida Keys, with approximately 65% ( deer in 2000) of the overall population found on Big Pine Key (BPK, 2,548 ha; Hardin et al. 1984, Lopez et al. 2004a). Since the 1960s, deer vehicle collisions (DVCs) have been the largest Key deer mortality factor, accounting for.50% of annual losses (Silvy 1975, Lopez et al. 2003c). Approximately 92% of DVCs result in deer mortality, which can have a significant impact on white-tailed deer populations including the endangered Florida Key deer (Allen and McCullough 1976, Lopez et al. 2003c). Additionally, in the United States, 720,000 1,500,000 estimated DVCs occur each year, resulting in approximately 29,000 human injuries and 211 human fatalities (Conover et al. 1995, Forman et al. 2003). United States Fish and Wildlife Service (USFWS) and Florida Department of Transportation (FDOT) biologists have attempted to address DVCs on United States Highway 1 (US 1; focusing particularly on the section that bisects BPK; Fig. 1). In 1994, the Key Deer Motorist Conflict Study was initiated by FDOT to evaluate alternatives for reducing DVCs on US 1 (Calvo 1996). Furthermore, in 1995, the level of service (i.e., ability to evacuate residents via vehicles during a hurricane) was found to be inadequate on BPK and No Name Key (NNK; Lopez et al. 2003b). In an effort to decrease DVCs and increase US 1 traffic flow, the Key Deer Motorist Conflict Study recommended the US 1 Project, a 2-prong approach consisting of 1) a combination of fences, 2 underpasses, and 4 deer guards along the 2.6-km undeveloped section of US 1 on BPK, and 1 iparker@tamu.edu 2) an extra northbound lane through part of the 3-km developed segment of US 1 on BPK (Calvo 1996, Harveson et al. 2004; Fig. 2). A portion of US 1, the developed business segment that included the extra traffic lane, was not fenced due to potential economic losses (i.e., restricted business access in an area with a tourist-based economy; Calvo 1996, Lopez et al. 2003a). To determine initial effects of the US 1 Project, Braden et al. (2008) monitored the US 1 Project one year postconstruction (Jan 2003 Dec 2003). We incorporated that first year of data from Braden et al. (2008) and conducted 2 additional years (Jan 2004 Dec 2005) of data collection to determine effects of the US 1 Project on Key deer mortality. Deer mortality is the ultimate indicator of the effectiveness of fencing on US 1. With the completion of construction of the US 1 Project in 2002, our objective was to evaluate the effectiveness (3 yr postconstruction) of fencing, underpasses, and experimental deer guards in reducing Key deer mortality. To evaluate effectiveness, we sought to understand the dynamics of DVCs, deer population trends, deer underpass use, and exclusion efficacy of deer fencing over the course of the 3- year project. STUDY AREA The Florida Keys are a chain of islands 200 km in length stretching southwest from the southern coast of Florida. Two adjacent islands, BPK (2,522 ha) and NNK (459 ha), formed the core habitat for Florida Key deer (Lopez et al. 2005). We conducted our study primarily on the southern half of BPK but incorporated many areas of intersection between roadways and Key deer habitat. United States Highway 1 was a 2-lane highway that linked the Keys to the mainland with an estimated annual average daily traffic 354 The Journal of Wildlife Management 72(2)

2 Figure 2. Florida Key deer United States Highway 1 (US 1) Project area (length ¼ 5.6 km) on Big Pine Key, Florida, USA, US 1 is divided into unfenced (3.1-km, solid line [A þ B þ C]) and fenced (2.6-km, dashed line) segments. The unfenced road section consists of a west (0.8-km [A]), extra lane (1.4-km [B]), and east (0.8-km [C]) segment. The fenced section includes 2 underpasses (denoted by U) and 4 experimental deer guards (indicated by arrows and numbered). Gray areas denote developed areas. Figure 1. Roadways (United States Highway 1 [US 1], other roads [dashed gray lines]) and US 1 Project area for Florida Key deer on Big Pine Key (north and south, separated by dotted line), Monroe County, Florida, USA, volume of approximately 18,000 vehicles per day (Monroe County; Florida Department of Transportation 2006). Maximum speed limits were 72 km/hour during the day and 56 km/hour at night. United States Highway 1 traversed an elevational gradient on BPK, entering at lowlying coastal areas and increasing in elevation near the midpoint of US 1 on BPK. Vegetative communities in the Florida Keys are dependent upon elevation and are nonrandomly selected by Key deer (Lopez 2001). Vegetation near sea level and in tidal areas on BPK was comprised of black mangrove (Avicennia germinans), red mangrove (Rhizophora mangle), white mangrove (Laguncularia racemosa), and buttonwood (Conocarpus erectus) forests. With increasing elevation, maritime zones transitioned into hardwood (e.g., gumbo limbo [Bursera simaruba], Jamaican dogwood [Piscidia piscipula]) and pineland (e.g., slash pine [Pinus elliottii], saw palmetto [Serenoa repens]) upland forests with vegetation intolerant of salt water (Dickson 1955, Folk 1991, Lopez et al. 2004b). METHODS Underpass Use We placed TrailMaster 1500 Active Infrared Trail Monitors (TrailMaster, Goodson and Associates, Inc., Lenexa, KS) in the center of each underpass (north underpass, south underpass) to monitor deer movements (Braden et al. 2008; Fig. 2). Camera stations collected data for 3 years postproject and we set them to take pictures throughout the day ( hr) with a camera delay of 2 minutes, which was sufficient to avoid double-counting (Braden et al. 2008). These camera stations collected data for date, number, sex, age, and location of deer all 3 years postconstruction. Deer Vehicle Collisions Since 1966, USFWS biologists have recorded Key deer mortality (hereafter USFWS mortality data) on all roads on BPK via direct sightings, citizen and law enforcement reports, and observation of turkey vultures (Cathartes aura; Lopez et al. 2003c). We recorded age, sex, and body mass for each dead animal and entered all vehicle-related deer mortality locations into both ArcView (Version 3.2) and Microsoft Access (Version 2000; Microsoft, Inc., Redmond, WA). In addition to Key deer mortality data, we also obtained USFWS annual deer survey data ( ; Lopez et al. 2004a). Deer Incidents We recorded the number, sex, age, and point of entry of deer entering the fenced roadway (hereafter deer incidents) Parker et al. Reducing Mortality of Florida Key Deer 355

3 construction to years 2 and 3 postconstruction for the north (2004, increase ¼ 57%, P ¼ 0.003; 2005, increase ¼ 55%, P ¼ 0.008) and south (2004, increase ¼ 50%, P ¼ 0.012; 2005, increase ¼ 44%, P ¼ 0.058) underpasses (Fig. 3). Figure 3. Mean monthly camera exposures per underpass (north and south) for Florida Key deer on United States Highway 1, Big Pine Key, Florida, USA, based on USFWS biologist sightings or law enforcement reports. Personnel quickly responded to all deer incidents, aided in live-deer removal if necessary, and inspected fence for incursion points. Deer unable to exit on their own were herded out of the area through fence gates. Data Analysis We compared average monthly underpass use postproject completion ( ) for each underpass using analysis of variance (Ott 1993). We separated differences using Tukey s honestly significant differences test where appropriate (Fowler et al. 1998; SPSS Version 11.5; SPSS Inc., Chicago, IL). Although we analyzed DVCs throughout the Key deer habitat we focused primarily on segments of US 1 on BPK preconstruction ( ) and postconstruction ( ; Fig. 2). We omitted mortality data from 2001 and 2002 due to project construction (Braden et al. 2008). We compared annual US 1 DVCs pre- and postconstruction by sex, age, and area (road segments). Previous research reported DVCs are a function of population size (Lopez et al. 2005); thus, we accounted for population size by dividing DVCs by a population index (i.e., mean monthly no. of deer seen annually along standardized route; Lopez et al. 2004a). RESULTS Underpass Use Key deer combined underpass use differed during study years ( ; F 2,67 ¼ 10.9, P, 0.001). Underpass use by Key deer increased throughout 2003 (n ¼ 871 exposures [1 exposure ¼ 1 deer]) to 2004 (n ¼ 1,857 exposures) but stabilized by the third year (2005, n ¼ 1,629 exposures). In combining data for both underpasses, underpass use in the initial postconstruction study year (2003) was lower than the subsequent 2 study years (2004, increase ¼ 53%, P, 0.001; 2005, increase ¼ 49%, P ¼ 0.002). We did not find the 2004 and 2005 study years to be significantly different (P ¼ 0.786). Key deer use of the south underpass was greater than the north underpass use for all 3 years (mean difference ¼ 32%, F 1,70 ¼ 7.52, P ¼ 0.008, Fig. 3). In comparing camera exposures for individual underpasses between years, we found underpass use increased from the first year post- Deer Vehicle Collisions Immediately following construction, DVCs decreased (2003, n ¼ 3; 2004, n ¼ 1; 2005, n ¼ 0) within the fenced section of US 1, which represents an approximately % decrease (from range of DVCs/yr, ). In contrast, new hotspots sprang up west of the fenced area, because DVCs increased approximately 26 50% within the unfenced section of US 1 (Table 1). In all unfenced segments of US 1, DVCs generally increased and total DVCs (i.e., all roads in deer habitat) reached a record level of 100 in 2005 (Table 1, Fig. 4). Overall, there was no difference in the mean (6 SD) number of DVCs on US 1 preconstruction (x ¼ , ) and postconstruction (x ¼ , ; Table 1; Fig. 4). The extra lane segment (preconstruction, x ¼ ; postconstruction, x ¼ ) and east segment (preconstruction, x ¼ 8 6 2; postconstruction, x ¼ ) showed small increases in DVCs from pre- to postfence; however, the largest increase in DVCs for the undeveloped section was the west segment (preconstruction, x ¼ 6 6 4; postconstruction, x ¼ ; Table 1; Fig. 4). Observed increases in mean DVCs pre- to postconstruction for the undeveloped sections of US 1 were 25% (east), 50% (extra lane), and 150% (west; Table 1; Fig. 4). Review of USFWS mortality and road survey data indicated a concurrent increase in both overall DVCs and deer population postconstruction ( ; Fig. 5). Total DVCs on BPK also appear to have increased postconstruction, suggesting the observed increase in US 1 DVCs was likely related to increased deer densities (Table 1; Fig. 5). In reviewing the ratio of US 1 DVCs to average number of deer seen annually, trend data suggest that the risk to a deer of being struck by a vehicle on US 1 declined postconstruction despite increases in population densities on BPK (Fig. 6). Table 1. Annual Key deer vehicle collisions along United States Highway 1 (US 1) by fenced and unfenced (A þ B þ C) highway segments on Big Pine Key (BPK), Florida, USA, and Period West (A) Extra lane (B) East (C) Fenced Total US 1 BPK roads Preproject x Postproject x The Journal of Wildlife Management 72(2)

4 Figure 4. Annual Key deer vehicle collisions (DVCs) by United States Highway 1 (US 1) road segment (west, extra lane, east, fenced segment) and combined segments (unfenced and fenced) for prefence ( ) and postfence ( ) periods on Big Pine Key, Florida, USA. Deer Incidents Deer entered the fenced area of US 1 (presumably over a deer guard) 13 times following construction of the US 1 Project: 5 crossings in 2003 (5 ad [4 M, 1 F]), 4 crossings in 2004 (3 ad [2 M, 1 F], 1 yearling [1 M]), and 4 crossings in 2005 (2 yearlings [1 M, 1 F], 1 fawn [unknown sex], 1 unknown deer). An additional 10 deer breached the fencing through opened gates, erosion, or damaged fencing: 1 adult female and 1 unknown in 2003, and 2 adults (1 M, 1 F), 4 yearlings (3 M, 1 unknown sex), and 2 unknown age deer in An unusually active hurricane season in 2005 damaged US 1 fencing and precipitated an increase in breaching events for that year. Within the fenced segment of the project area, over the course of the study ( ) 23 deer incidents resulted in 3 Key deer mortalities (n ¼ 2, vehicle collision; n ¼ 1, severe injury during removal attempt, euthanized). DISCUSSION We found that the US 1 Project successfully reduced the risk of DVCs for Florida Key deer. Our analyses of DVCs, deer population trends, deer underpass use, and deer incidents all indicated that deer benefited from the US 1 Project by avoiding the fence sections through heavy use of underpasses. However, increasing deer density in the core habitat has and will continue to contribute heavily to DVCs. Underpass Use Echoing findings of previous deer studies, the presence of 2 underpasses improved permeability of the fenced area for Parker et al. Reducing Mortality of Florida Key Deer 357

5 Figure 5. Monthly mean of Key deer seen annually along standardized route (monthly survey) compared to deer vehicle collisions (DVCs; United States Highway 1 [US 1]) on Big Pine Key (BPK), Florida, USA, and Deer vehicle collisions occurring only on US 1 on BPK (US 1 DVCs) are differentiated from DVCs occurring on all roads on BPK (Total DVCs, includes US 1). Figure 6. Comparison of deer vehicle collisions (DVCs) along United States Highway 1 (US 1) on Big Pine Key, Florida, USA, monthly mean of deer seen annually on Big Pine Key (monthly survey), and ratio of DVCs to deer seen during monthly survey, and Key deer (Reed et al. 1975, Foster and Humphrey 1995). We observed increasing use of underpasses by Key deer 3 years postconstruction, indicating deer acclimatized to the presence of underpasses. The observed decrease in underpass use in 2005 was likely attributable to removal of camera stations on 4 separate occasions for a total of 4 weeks due to an unusually active hurricane season. The mean monthly camera exposures for combined underpasses for 2005 was 71, indicating a relatively low loss of data for those 4 weeks. Deer Vehicle Collisions Along the fenced section of US 1 DVCs decreased from pre- to postconstruction years, although 100% effectiveness (i.e., no deer inside the fence) was not achieved and was believed to be an impractical goal, as is the case with many deer exclusionary fencing projects (Woods 1990, Putnam 1997, USFWS 2006). We observed increases in DVCs following project completion along the unfenced segment of US 1, which could be explained by 1) natural increases in mortality associated with fence ends (east segment; Ward 1982, Feldhamer et al. 1986), 2) addition of an extra 1.4-km traffic lane in the unfenced section of US 1, 3) habitat improvement work along US 1 (west and extra lane segments), and 4) an increase in deer population numbers on BPK (Lopez et al. 2004a). The small increase in mortality observed at the fence end (þ25%) was expected but likely had a relatively small impact on overall DVCs. It is possible that the increase in mortality in the extra lane (þ50%) occurred due to the associated increased traffic flow (e.g., higher average speeds, more vehicles/hr), reduced deer visibility, and the additional hazard of deer having to cross 3 lanes of traffic versus 2 (Lopez et al. 2003a, USFWS 2006). It is also possible that some deer chose to avoid the extra lane segment and crossed US 1 in the west segment, resulting in additional DVCs in that segment (þ150%). Additionally, USFWS undertook a habitat restoration project (i.e., removal of exotic plants, waterhole creation) along the extra lane and west segments of US 1. Carbaugh et al. (1975) and Bashore et al. (1985) found that attractive habitat near roadways in Pennsylvania, USA, led to increased deer presence or lower roadside visibility. Research conducted by Hedlund et al. (2004) and Lopez et al. (2005) supports the idea that increased deer density in areas of high traffic volume would lead to increased DVCs. Although it is likely that all of these points contributed to the location and quantity of DVCs pre- and postconstruction, an increase in deer population appears to be the major factor. Our analysis supports the conclusion that the major contributor to postconstruction DVC numbers on US 1 is an increasing deer density in the core habitat. Caution is warranted, however, because the USFWS Biological Opinion within the Big Pine Key No Name Key Habitat Conservation Plan recommended an additional 7 years of data collection for the US 1 Project (USFWS 2006). Deer Incidents Deer crossed the 4 experimental deer guards proposed by Peterson et al. (2003) 13 times to enter the fenced segment. Although pen trials found deer guards to be 99.5% effective, we were unable to determine how many deer guard crossing attempts occurred during pre- or postfence periods. However, as evidenced by the decrease in deer incidents and DVCs and the easy movement of cars and people, deer guards successfully allowed movement of vehicular, bicycle, and human foot traffic while greatly restricting deer access to the fenced area. The relatively large differential between number of deer incidents (n ¼ 23) and DVCs (n ¼ 3) in the fenced area over the same time period indicated that intrusion (e.g., over deer guards, through breaches due to erosion, damage, or open gates) would not automatically lead to deer mortality. Key deer sociobiology and the necessity for a fencing adjustment period may explain some deer intrusion into the fenced area. Previous fencing studies have found that an acclimation period exists with wildlife fencing structures (Reed et al. 1975, Clevenger 1998, Hardy et al. 2004). Additionally, Key deer are known to have strong site and movement pattern fidelity (Lopez 2001). These 2 factors resulted in deer crossings as deer attempted to revert to prefence movements 358 The Journal of Wildlife Management 72(2)

6 and ranges. The number of these reminiscence deer crossings should decrease as older deer acclimate to the location of crossings and as younger deer establish ranges with the fencing project in place (Braden 2005). Overall, the Key deer incidents highlight the need for 2 things: 1) easy exit for deer from the fenced area and 2) thorough maintenance of all aspects of the fence. MANAGEMENT IMPLICATIONS The US 1 Project succeeded in reducing DVC risk on US 1, and the overall success demonstrated the absence of fundamental flaws in the methods (i.e., fencing, underpasses, and deer guards). Therefore, managers can mold these techniques to communities experiencing unacceptable levels of DVCs (e.g., fencing and deer guards without underpasses). Incorporation of specially designed deer guards was an especially useful and unique facet that allowed safe passage for humans on foot, on bicycles, and in vehicles. ACKNOWLEDGMENTS We thank J. Palenchar, D. E. Watts, S. N. Kahlich, C. W. Roberts, P. A. Frank, and the staff of the National Key Deer Refuge for assistance in monitoring and maintaining the US 1 Project area. This research was supported by the Florida Department of Transportation. LITERATURE CITED Allen, R. E., and D. R. McCullough Deer-car accidents in southern Michigan. Journal of Wildlife Management 40: Bashore, T. L., W. M. Tzilkowski, and E. D. Bellis Analysis of deer vehicle collision sites in Pennsylvania. Journal of Wildlife Management 49: Braden, A. W Evaluation of the effects of a highway improvement project on Key deer. Thesis, Texas A&M University, College Station, USA. Braden, A. W., R. R. Lopez, C. W. Roberts, N. J. Silvy, C. B. Owen, and P. A. Frank Florida Key deer underpass use and movements along a highway corridor. Wildlife Biology 13:in press. Calvo, R US-1/SR 5 Key deer/motorist conflict study report. Dames and Moore, Miami, Florida, USA. Carbaugh, B., J. P. Vaughn, E. D. Ellis, and H. B. Graves Distribution and activity of white-tailed deer along an interstate highway. Journal of Wildlife Management 39: Clevenger, A. P Permeability of the Trans-Canada highway to wildlife in Banff National Park: importance of crossing structures and factors influencing their effectiveness. Pages in Proceedings of the International Conferences on Ecology and Transportation February 1998, Fort Myers, Florida, USA. Conover, M. R., W. C. Pitt, K. K. Kessler, T. J. Dubow, and W. A. Sanborn Review of human injuries, illnesses, and economic losses caused by wildlife in the United States. Wildlife Society Bulletin 23: Dickson, J. D., III An ecological study of the Key deer. Florida Game and Fresh Water Fish Commission Technical Bulletin 3, Tallahassee, USA. Feldhamer, G. A., J. E. Gates, D. M. Harman, A. J. Loranger, and K. R. Dixon Effects of interstate highway fencing on white-tailed deer activity. Journal of Wildlife Management 50: Florida Department of Transportation annual average daily traffic (AADT) reports. Transportation Statistics Office, Tallahassee, Florida, USA. Folk, M. L Habitat of the Key deer. Dissertation, Southern Illinois University, Carbondale, USA. Forman, R. T., D. Sperling, J. A. Bissonette, A. P. Clevenger, C. D. Cutshall, V. H. Dale, L. Fahrig, R. France, C. R. Goldman, K. Heanue, J. A. Jones, F. J. Swanson, T. Turrentine, and T. C. Winter Road ecology: science and solutions. Island Press, Washington, D.C., USA. Foster, M. L., and S. R. Humphrey Use of underpasses by Florida panthers and other wildlife. Wildlife Society Bulletin 23: Fowler, J., L. Cohen, and P. Jarvis Practical statistics for field biology. Second edition. John Wiley and Sons, Chichester, West Sussex, United Kingdom. Hardin, J. W., W. D. Klimstra, and N. J. Silvy Florida Keys. Pages in L. K. Halls, editor. White-tailed deer: ecology and management. Stackpole, Harrisburg, Pennsylvania, USA. Hardy, A., A. P. Clevenger, M. Huijser, and G. Neale An overview of methods and approaches for evaluating the effectiveness of wildlife crossing structures: emphasizing the science in applied science. Pages in C. L. Irwin, P. Garrett, and K. P. McDermott, editors. Proceedings of the 2003 International Conference on Ecology and Transportation. Center for Transportation and the Environment, North Carolina State University, Raleigh, USA. Harveson, P. M., R. R. Lopez, N. J. Silvy, and P. A. Frank Sourcesink dynamics of Florida Key deer on Big Pine Key, Florida. Journal of Wildlife Management 68: Hedlund, J. H., P. D. Curtis, G. Curtis, and A. F. Williams Methods to reduce traffic crashes involving deer: what works and what does not. Traffic Injury Prevention 5: Lopez, R. R Population ecology of Florida Key deer. Dissertation, Texas A&M University, College Station, USA. Lopez, R. R., P. M. Harveson, M. N. Peterson, N. J. Silvy, and P. A. Frank Density effects on ranges of the endangered Florida Key deer. Wildlife Society Bulletin 33: Lopez, R. R., C. B. Owen, and C. L. Irwin. 2003a. Conservation strategies in the Florida Keys: formula for success. Pages in C. L. Irwin, P. Garrett, and K. P. McDermott, editors. Proceedings of the International Conference on Ecology and Transportation. Center for Transportation and the Environment, North Carolina State University, Raleigh, USA. Lopez, R. R., N. J. Silvy, R. F. Labisky, and P. A. Frank. 2003b. Hurricane impacts on Key deer in the Florida Keys. Journal of Wildlife Management 67: Lopez, R. R., N. J. Silvy, B. L. Pierce, P. A. Frank, M. T. Wilson, and K. M. Burke. 2004a. Population density of the endangered Florida Key deer. Journal of Wildlife Management 68: Lopez, R. R., N. J. Silvy, R. N. Wilkins, P. A. Frank, M. J. Peterson, and M. N. Peterson. 2004b. Habitat use patterns of Florida Key deer: implications of urban development. Journal of Wildlife Management 68: Lopez, R. R., M. E. P. Vieira, N. J. Silvy, P. A. Frank, S. W. Whisenant, and D. A. Jones. 2003c. Survival, mortality, and life expectancy of Florida Key deer. Journal of Wildlife Management 67: Ott, R. L An introduction to statistical methods and data analysis. Fourth edition. Duxbury Press, Belmont, California, USA. Peterson, M. N., R. R. Lopez, N. J. Silvy, C. B. Owen, P. A. Frank, and A. W. Braden Evaluation of deer-exclusion grates in urban areas. Wildlife Society Bulletin 31: Putnam, R. J Deer and road traffic accidents: options for management. Journal of Environmental Management 51: Reed, D. F., T. N. Woodard, and T. M. Pojar Behavioral response of mule deer to a highway underpass. Journal of Wildlife Management 39: Silvy, N. J Population density, movements, and habitat utilization of Key deer, Odocoileus virginianus clavium. Dissertation, Southern Illinois University, Carbondale, USA. U.S. Fish and Wildlife Service [USFWS] Big Pine Key No Name Key Habitat Conservation Plan. U.S. Department of the Interior, Washington, D.C., USA. Ward, A. L Mule deer behavior in relation to fencing and underpasses on Interstate 80 in Wyoming. Transportation Research Record 859:8 13. Woods, J. G Effectiveness of fences and underpasses on the Trans- Canada Highway and their impact on ungulate populations. Environment Canada, Park Service, Ottawa, Ontario, Canada. Associate Editor: Euler. Parker et al. Reducing Mortality of Florida Key Deer 359