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Habitat Utilization of Pituophis melanoleucus melanoleucus (Northern Pinesnakes) on Arnold Air Force Base in Middle Tennessee
Gary W. Gerald, Mark A. Bailey, and Jeff N. Holmes

Southeastern Naturalist, Volume 5, Number 2 (2006): 253–264

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2006 SOUTHEASTERN NATURALIST 5(2):253–264 Habitat Utilization of Pituophis melanoleucus melanoleucus (Northern Pinesnakes) on Arnold Air Force Base in Middle Tennessee Gary W. Gerald1,2,*, Mark A. Bailey3, and Jeff N. Holmes4 Abstract - Radio-transmitters were implanted in six male and three female adult Northern Pinesnakes at Arnold Air Force Base in Middle Tennessee. Snakes were radio-tracked during the spring, summer, and autumn of 2001 and 2002 to ascertain possible sexual variation and seasonal patterns of habitat use. Radio-tracked Pinesnakes spent most of their time within pre-existing stump holes or under old concrete foundations found scattered throughout the study area. They primarily used disturbed habitats with little or no canopy cover. Selected habitats were characterized by vegetative ground cover and woody debris during both years. Monitored pinesnakes avoided upland deciduous forest and closed-canopy pine forests. The affinity for open-canopy areas increased throughout the year, with males and females inhabiting these areas most often during autumn. Females used more underground retreats than males during summer. Moreover, both sexes used underground retreats most often during autumn. Considering past and ongoing land use patterns of the area, disturbance (e.g., fire and timber harvest) may be important to the maintenance of habitat diversity needed by Northern Pinesnakes. Introduction Despite recent advances in the study of snake ecology (e.g., Blouin- Demers and Weatherhead 2001, Shine et. al 2003), we still know relatively little about many aspects of the natural history, including habitat selection, of many species. Habitat selection refers to the preference for certain habitat types relative to its availability within an animal’s activity range (White and Garrott 1990). Descriptions of habitat use are available for many large North American snake species. However, these are often based on chance observations of individual snakes. Radiotelemetry is an effective method for obtaining detailed information on habitat utilization in secretive, inconspicuous snakes (Durner and Gates 1993, Reinert 1993). Pituophis melanoleucus melanoleucus Daudin (Northern Pinesnake) is a large, terrestrial snake limited in distribution to a series of disjunct populations scattered throughout the Southeast and Mid-Atlantic States (Conant and Collins 1991, Stull 1940). Currently, Pituophis m. melanoleucus is listed as “threatened” in Tennessee and New Jersey, and is a species of “special concern” in Kentucky, Alabama, Georgia, Mississippi, North Carolina, and 1Department of Biology, Middle Tennessee State University, Murfreesboro, TN. 2Current address - Department of Zoology, Miami University, Oxford, OH. 3Conservation Southeast, Shorter, AL. 4Conservation Southeast, Nashville, TN. *Corresponding author - geraldgw@muohio.edu. 254 Southeastern Naturalist Vol. 5, No. 2 South Carolina (Bailey et al. 2003, McCoy et al. 2001, Zappalorti et al. 2004). Because of its scarcity, few ecological studies have been conducted on this species (Burger and Zappalorti 1988, 1989, 1991; Zappalorti et al. 1983). Northern Pinesnakes generally have been associated with upland forests that are typically dominated by pines (Conant and Collins 1991, Woodward and Barthalmus 1992). The only detailed studies of habitat utilization by the Northern Pinesnake were conducted in a disjunct population located in the northern-most part of their range, the New Jersey Pine Barrens (Burger and Zappalorti 1988, 1989; Zappalorti et al. 1983). Pinesnakes from New Jersey selected habitats within pine-oak and oak-pine forests and utilized open, sunny areas containing low levels of human disturbance for nesting (Burger and Zappalorti 1988). Arnold Air Force Base (AAFB) in Middle Tennessee harbors a population of Northern Pinesnakes in habitats that differ from those of the New Jersey Pine Barrens (Miller et al. 2005). To achieve a better understanding of habitats used by Northern Pinesnakes in the southern part of their range, radiotelemetry was used to obtain data on habitat use and assess potential sexual and seasonal variation in habitat usage. Study Site Arnold Air Force Base is a 15,822-ha military reservation located in the Interior Low Plateau ecoregion of the Eastern Highland Rim physiographic province (Franklin and Coffee Counties, 35.3560°N, 86.1500°W, ca. 335 m elevation). The pre-settlement upland forests of this region are believed to have been fire-maintained oak savanna (Pyne 2000). Today, AAFB has a variety of upland habitats, including mowed grasslands (airfields, utility rights-of-way, wildlife food plots), open oak savanna (in areas subjected to active ecological restoration management), fire-suppressed mature closed-canopy oak-hickory woodland, and intensively managed Pinus taeda L. (loblolly pine) plantations ranging from clear-cuts to mature stands (Pyne 2000). Most Pinesnakes were captured and tracked in the southwest region of AAFB that was one of the Army’s largest training bases and prisoner-of-war camps between 1941 and 1946 (Pyne 2000). All that remains from that era in the area is the road network, brick chimneys, sewers, and concrete foundations of the buildings (Pyne 2000). Today, this area is a matrix of plots containing mature and young loblolly pine stands, deciduous forests, frequently mowed grassy areas, oak barrens, freshly disturbed clear-cuts, burned plots, and open savannas. The deciduous forests are mostly firesuppressed and characterized by various native Quercus sp. (Quercus falcata Michaux, Q. coccinea Muenchhausen, Q. stellata Wangenheim, Q. marilandica Muenchhausen, Q. velutina Lamarck) and Carya alba Nuttal ex. Elliott, Cornus florida Linnaeus, Sassafras albidum Nuttall and Acer rubrum Linnaeus. One barrens-restoration area, adjacent to the study site, consists of frequently-burned oak barrens. 2006 G.W. Gerald, M.A. Bailey, and J.N. Holmes 255 Methods This study was conducted from March 2001 to November 2002. Large box-funnel traps, used successfully by Duran (1998) to capture Pituophis melanoleucus lodingi Blanchard (Black Pinesnakes), were used to capture Northern Pinesnakes from March to September during 2001 and 2002. During 2001, four males and three females were radio-tracked. During 2002, three males and two females from the previous year were radiotracked. Radio signals for two snakes (No. 5 and No. 6) were lost shortly after spring emergence in 2002. Two additional males were captured and radio-tracked during 2002. Therefore, a total of six male and three female Northern Pinesnakes were used to assess habitat use during 2001 and 2002 (Table 1). Northern Pinesnakes used in this study were surgically implanted with SI-2 radio-transmitters (Holohil Systems, Ltd., ON, Canada) following the procedure of Reinert and Cundall (1982). The transmitter package weighed approximately 12.7 g, contained a 20-cm wire antenna, and had a life span of 18–24 months. Transmitter mass was 1.7% of the smallest snake’s mass used in the study. Passive Integrative Transponder (PIT) tags were injected into the abdominal cavity and ventral scales were clipped to uniquely mark each individual. After surgery, each snake was held captive at least 24 h and released at its original point of capture. With the aid of radiotelemetry, data collection on habitat use was obtained from 20 April to 14 November 2002. Snakes were located using a hand-held antenna and an LA12-Q radiotelemetry receiver (AVM Instrument Co., Livermore, CA). When a snake was relocated visually, an attempt was made to minimize disturbance, so that our presence would not cause snakes to move away from their selected habitat. During 2001, attempts were made to relocate snakes twice daily, five days per week, until all snakes entered hibernacula. During 2002, attempts to relocate Pinesnakes occurred Table 1. Summary of all Northern Pinesnakes captured during this study and the total numbers of observations and locations for each individual. SVL = snout-vent length, obs = observations, loc = locations, 01 = 2001, 02 = 2002. Snake ID Sex SVL (mm) Weight (g) Dates tracked # obs # loc 3 M 1230 1370 11 April 01–14 Nov 02 242 92 4 M 1527 1500 7 May 01–14 Nov 02 256 62 5 M 1408 1210 12 May 01–14 Nov 02 160 46 8 M 1350 1295 21 Aug 01–14 Nov 02 105 25 11 M 1335 1100 17 June 02–14 Nov 02 64 23 12 M 1393 1320 23 July 02–14 Nov 02 42 18 2 F 1285 745 9 April 01–14 Nov 02 268 76 6 F 1440 1540 18 May 01–29 Mar 02 134 44 7 F 1380 1615 12 June 01–14 Nov 02 188 61 Mean 1372 1300 162 50 256 Southeastern Naturalist Vol. 5, No. 2 four times per week. Snakes were not radio-tracked from 25 November 2001 to 14 March 2002 due to inactivity associated with overwintering. The position of each snake, which refers to the specific microhabitat of the snake (e.g., underground, under debris, on the surface), was recorded each time a snake was relocated (observed). Snakes frequently remained hidden in a shelter for several days. Consequently, an observation was defined as each time a particular snake was radio-tracked within its habitat. A new location was recorded each time a snake was found at a position it previously had not been observed. Therefore, if a snake was radio-tracked daily, moved to a new shelter site and remained there for 5 days, then one location and five observations were recorded. Habitat data were collected at each new location. Habitat variables recorded include substrate type (< 50% herbaceous, > 50% herbaceous, leaf/straw litter, concrete), canopy type (e.g., hardwood, pine, mixed pine-hardwood, dense thicket, none), percent canopy cover, and the number of trees (at least 7.5-cm diameter at breast height) within a 10-m radius of the snake’s position. Survey flagging bearing the date and snake’s frequency number was used to temporarily mark locations. A Trimble Pathfinder global positioning system (GPS; Trimble Navigation Ltd., Sunnyvale, CA) was used to record flagged positions. Habitat selection was determined by comparing habitats used by radiotracked snakes with available habitat. Habitat availability was measured by gathering data on the same habitat variables at random points located within the study area. Random points were obtained by using a random point generator on the geographic information system (GIS) ArcView 3.2 (Environmental Systems Research Institute, Inc., Redlands, CA). A chi-square analysis designed by Dasgupta and Alldredge (2002) was used to determine if each snake selected certain habitats compared to the availability of those habitats. This method allows one to test the hypothesis that snakes do not use habitats in proportion to availability while mitigating problems associated with non-independence of relocation data and without pooling data for all animals. This procedure uses the maximum of the joint chi-square as the maximum-order statistic used to compare to a critical value defined as 1 - (1- α) 1/t with h-1 degrees of freedom, where t = number of snakes and h = number of habitat categories for each variable (Dasgupta and Alldredge 2002). A test for multiple comparisons of habitat types designed by Dasgupta and Alldredge (2002) was used to see which habitats were selected or avoided by each individual snake. To examine seasonal differences in habitat utilization among all snakes, the field season was divided into spring (March–May), summer (June– August), and autumn (September–November), and chi-square G tests of independence were performed among pooled data (White and Garrott 1990). This method has been widely criticized because of problems with pooling 2006 G.W. Gerald, M.A. Bailey, and J.N. Holmes 257 data among animals and because relocations of animals are not necessarily independent (Dasgupta and Alldredge 1998). Despite these common criticisms, this test is useful in identifying differences between sexes and trends among seasons in habitat-utilization data collected via radiotelemetry. We also believe that the non-independence of relocations is not a major issue because of the unit-sum constraint among the multinomial data and the nature of the question being investigated. Results During this study, Pinesnakes were most active during May and July of both years. Snakes were radio-tracked 1461 times at 449 different locations during 2001 and 2002 (Table 1). No differences in habitat use variables or available habitat were detected between 2001 and 2002. As a result, data for each individual and availability data were pooled for all subsequent analyses. Snakes spent the majority of their time underground in stump holes or within remnant concrete foundations scattered throughout the study area (Table 2). Snakes were located above ground in only 16% and 15% of observations during 2001 and 2002, respectively. All Northern Pinesnakes significantly used habitats disproportionately compared to available habitats. Compared to available substrates, snakes significantly utilized substrates consisting of > 50% herbaceous groundcover and Table 2. Proportion of positions within selected habitat(s) by Pituophis melanoleucus melanoleucus (Northern Pinesnakes) radio-tracked during 2001 (N = 985) and 2002 (N = 476). Under- In concrete Under Snake ID Sex ground foundation In open debris Undetermined 2001 2 F 0.30 0.40 0.09 0.07 0.13 3 M 0.18 0.18 0.15 0.08 0.40 4 M 0.26 0.47 0.11 0.02 0.14 5 M 0.51 0.14 0.15 0.04 0.15 6 F 0.56 0.02 0.27 0.07 0.07 7 F 0.31 0.18 0.19 0.08 0.24 8 M 0.63 0.00 0.33 0.04 0.00 Total 0.36 0.24 0.16 0.06 0.18 2002 2 F 0.55 0.32 0.08 0.03 0.01 3 M 0.26 0.26 0.22 0.09 0.17 4 M 0.21 0.32 0.19 0.01 0.27 5 M 0.67 0.00 0.33 0.00 0.00 6 F 0.80 0.00 0.20 0.00 0.00 7 F 0.71 0.00 0.12 0.04 0.13 8 M 0.74 0.00 0.09 0.04 0.13 11 M 0.58 0.00 0.23 0.02 0.17 12 M 0.63 0.00 0.14 0.09 0.16 Total 0.51 0.15 0.15 0.05 0.14 258 Southeastern Naturalist Vol. 5, No. 2 avoided leaf/straw litter substrates (Table 3). Most Pinesnakes also selected areas with no canopy, but the canopy type least used varied among individuals (Table 4). Pituophis m. melanoleucus were found to utilize more areas with < 25% canopy cover relative to availability (Table 5). Snakes were infrequently found in areas with > 50% canopy cover during both years of the study. Moreover, Pinesnakes were found most often in Table 3. Proportion of usage of the 6 substrates by Pituophis melanoleucus melanoleucus (Northern Pinesnakes) with substrate availability measured at random points within the study area. P-values from chi-square analyses comparing each individual’s CMAX to a critical value of 16.45 with 5 degrees of freedom were < 0.0001 for all individuals and the total. A summary of ordered (least to most) relative habitat usage determined via multiple comparisons is also provided. Abbreviations: R = Road, C = Concrete, HL = < 50% herbaceous, HG = > 50% herbaceous, L = leaf/straw litter, O = other, and Avail. = available. Substrates Snake R C HL HG L O CMAX Usage 2 0.010 0.135 0.104 0.595 0.146 0.010 723.99 L < R < O < C < HL < HG 3 0.016 0.150 0.071 0.606 0.149 0.008 1132.80 L < HL < R < O < C < HG 4 0.033 0.168 0.033 0.700 0.033 0.033 352.81 L < O < HL < R < C < HG 5 0.017 0.068 0.153 0.576 0.169 0.017 133.88 L < R < O < C < HL < HG 6 0.020 0.020 0.373 0.353 0.156 0.078 178.47 L < R < C < HG < O < HL 7 0.015 0.030 0.121 0.728 0.045 0.061 176.12 L < R < C < HL < O < HG 8 0.025 0.025 0.100 0.650 0.150 0.050 64.84 L < R < C < HL < O < HG 11 0.000 0.000 0.000 1.000 0.000 0.000 57.73 12 0.000 0.000 0.000 1.000 0.000 0.000 40.63 Total 0.019 0.090 0.119 0.625 0.116 0.031 1813.49 L < R < C < HL < O < HG Avail. 0.039 0.003 0.090 0.319 0.547 0.002 Table 4. Proportion of usage of the 5 canopy types by Pituophis melanoleucus melanoleucus (Northern Pinesnakes) with the availability of canopy types measured at random points within the study area. P-values from chi-square analyses comparing each individual’s CMAX to a critical value of 16.45 with 5 degrees of freedom were < 0.0001 for all individuals and the total. A summary of ordered (least to most) relative habitat usage determined via multiple comparisons is also provided. Abbreviations: P = pine, H = hardwood, M = mixed pine/hardwood, T = thicket, and N = none. Canopy type Snake P H M T N CMAX Usage 2 0.415 0.043 0.297 0.117 0.128 33.63 H < T < N < P < M 3 0.283 0.063 0.378 0.055 0.221 50.97 H < T < P < M < N 4 0.181 0.012 0.193 0.241 0.373 115.34 H < P < M < T < N 5 0.293 0.069 0.138 0.121 0.379 51.76 H < M < P < T < N 6 0.250 0.058 0.038 0.019 0.635 149.85 M < H < T < P < N 7 0.231 0.015 0.046 0.077 0.631 181.69 H < M < P < T < N 8 0.026 0.282 0.281 0.026 0.385 38.85 P < T < H < M < N 11 0.037 0.074 0.222 0.037 0.630 74.39 H < P < T < M < N 12 0.285 0.048 0.048 0.048 0.571 50.22 M < H < T < P < N Total 0.253 0.062 0.217 0.095 0.373 459.08 H < P < M < T < N Available 0.282 0.312 0.227 0.066 0.113 2006 G.W. Gerald, M.A. Bailey, and J.N. Holmes 259 areas with ≤ 10 trees within 10 m of their selected habitat despite the limited availability of these areas, whereas snakes tended to avoid areas with > 11 trees within 10 m of their position (Table 6). Sexual and seasonal differences in habitat use Significant differences among individuals were detected for all habitat variables when data from all snakes were pooled. When individuals were Table 5. Proportion of usage of areas differing in % canopy cover by Pituophis melanoleucus melanoleucus (Northern Pinesnakes) with the availability of canopy types measured at random points within the study area. P-values are from chi-square analyses comparing each individual’s CMAX to a critical value of 12.56 with 3 degrees of freedom. A summary of ordered (least to most) relative habitat usage determined via multiple comparisons is also provided. Abbreviations: A = < 25%, B = 25–49%, C = 50–74%, and D = 75–100%. % canopy cover Snake A B C D CMAX P-value Usage 2 0.547 0.263 0.137 0.053 64.05 < 0.0001 D < C < B < A 3 0.476 0.119 0.135 0.270 25.04 0.0001 D < C < B < A 4 0.696 0.190 0.101 0.013 83.27 < 0.0001 D < C < B < A 5 0.737 0.175 0.070 0.018 68.24 < 0.0001 D < C < B < A 6 0.706 0.138 0.078 0.078 49.70 < 0.0001 D < C < B < A 7 0.763 0.105 0.079 0.053 46.16 < 0.0001 D < C < B < A 8 0.526 0.158 0.184 0.132 15.35 0.0090 D < C < B < A 11 0.741 0.185 0.074 0.000 33.61 < 0.0001 D < C < B < A 12 0.700 0.200 0.100 0.000 21.98 0.0005 D < C < B < A Total 0.618 0.171 0.113 0.098 357.73 < 0.0001 D < C < B < A Available 0.278 0.143 0.179 0.400 Table 6. Proportion of usage of areas that differ in tree density within 10 m by Pituophis melanoleucus melanoleucus (Northern Pinesnakes) with availability measured at random points within the study area. P-values are from chi-square analyses comparing each individual’s CMAX to a critical value of 12.56 with 3 degrees of freedom. A summary of ordered (least to most) relative habitat usage determined via multiple comparisons is also provided. Abbreviations: A = 0–10 trees, B = 11–20 trees, C = 21–30 trees, and D = > 30 trees. # of trees within 10 m Snake A B C D CMAX P-value Usage 2 0.853 0.116 0.011 0.020 162.58 < 0.0001 D < C < B < A 3 0.565 0.242 0.177 0.016 90.85 < 0.0001 D < C < B < A 4 1.000 0.000 0.000 0.000 213.05 < 0.0001 5 0.898 0.085 0.017 0.000 119.28 < 0.0001 D < C < B < A 6 0.882 0.059 0.059 0.000 94.09 < 0.0001 D < C < B < A 7 0.846 0.108 0.046 0.000 108.50 < 0.0001 D < C < B < A 8 0.684 0.210 0.053 0.053 38.65 < 0.0001 D < C < B < A 11 1.000 0.000 0.000 0.000 70.15 < 0.0001 12 0.921 0.050 0.029 0.000 42.73 < 0.0001 D < C < B < A Total 0.815 0.116 0.058 0.011 847.96 < 0.0001 D < C < B < A Available 0.532 0.353 0.088 0.027 260 Southeastern Naturalist Vol. 5, No. 2 grouped into the appropriate sex, no significant differences were detected. Hence, individuals were pooled by sex to assess potential sexual and seasonal patterns in habitat use. Although both sexes were relocated on substrates composed of > 50% herbaceous vegetation most often and leaf/straw litter least often during all three seasons, usage of > 50% herbaceous substrates increased from spring to summer to autumn, whereas, usage of leaf/straw litter substrates decreased proportionately throughout the year (Male: χ2 = 61.37, DF = 10, P < 0.001; Female: χ2 = 40.66, DF = 10, P < 0.001). Significant differences were detected for canopy type among seasons (Male: χ2 = 106.97, DF = 8, P < 0.001; Female: χ2 = 52.26, DF = 8, P < 0.001). During spring, both sexes spent more time in areas with pine canopies relative to other seasons. During summer, sexual differences were detected for canopy type (χ2 = 22.19, DF = 4, P < 0.001). Males occurred more often in habitat with no canopy and mixed pine-hardwood canopies than females, which used more areas comprised of pine canopies and no canopy, respectively. No differences between males and females or among seasons were found for % canopy cover usage (Male: χ2 = 6.12, DF = 3, P = 0.11; Female: χ2 = 4.07, DF = 3, P = 0.26). Both sexes exhibited seasonal variation in the tree densities of areas used (Male: χ2 = 29.75, DF = 6, P < 0.001; Female: χ2 = 20.51, DF = 6, P = 0.002). Snakes used a greater proportion of areas with ≤ 10 trees within 10 m of their relocation points during spring. A sexual difference was recorded during summer for tree density with males tending to use more areas containing > 20 trees than females (χ2 = 8.18, DF = 3, P = 0.044). Although Pinesnakes spent more time in areas with ≤ 10 trees within 10 m during autumn, both sexes used more areas with > 10 trees within a 10-m radius during autumn compared to spring or summer. Significant differences in snake retreat sites were detected between the sexes during summer (χ2 = 43.96, DF = 4, P < 0.001) and overall among seasons (χ2 = 270.16, DF = 8, P < 0.001). Females utilized more underground retreat sites than males during summer. Both sexes were found in under-ground retreats more often during autumn than during spring and summer. Hibernacula and nesting Contrary to communal aggregations seen with New Jersey pinesnakes (Burger and Zappalorti 1988; R.T. Zappalorti, Herpetological Associates, Inc., Jackson, NJ, pers. comm.), Pinesnakes at AAFB were not observed sharing overwintering sites during this study. In 2001, two females and four males hibernated individually in underground stump holes. One male (No. 4) hibernated in a mammal burrow, and one female (No. 2) overwintered within a concrete foundation. During 2002, two males (No. 4 and No. 8) returned to the same hibernacula site from the previous year. During 2006 G.W. Gerald, M.A. Bailey, and J.N. Holmes 261 2002, two males (No. 11 and No. 12) hibernated in stump holes located 28 m apart in a recently burned open-shrub savanna. Additionally, the hibernaculum occupied by snake No. 12 was also located only 27 m from a stump hole used as an overwintering site by male No. 5 the previous year. Two snakes (No. 3 and No. 7) hibernated in stump holes within a pine stand during 2001, which was logged and the ground surface heavily disturbed during 2002. Following timber harvest, these two snakes moved back into this area, which was left with very few recognizable landmarks, and were able to relocate and use stump holes to overwinter. These sites were located within 150–200 m of the hibernacula used by these snakes the previous year. Three adult female Pinesnakes were radio-tracked during this study, however, no nesting activity or nests were found despite frequent attempts to make these observations. Females were located most often in stump holes during the time when oviposition most likely occurred (i.e., late June or early July). Discussion Northern Pinesnakes at Arnold AFB were most often found using disturbed habitats with little or no canopy, and with a significant amount of vegetative groundcover. Considering the history of the study area (Pyne 2000), the mere presence of Northern Pinesnakes could be indicative of their preference for relatively disturbed areas. Zappalorti and Burger (1985) reported on the importance of disturbed sites to pinesnakes in the New Jersey Pine Barrens. Burger and Zappalorti (1988) found that Northern Pinesnakes used disturbed areas characterized by low tree density, little or no canopy cover, and low levels of human activity. The snakes in New Jersey used open areas for basking, foraging, and nesting, and were most often located inside logs or buried under leaves (Burger and Zappalorti 1988, 1989). Selection for areas with little or no canopy cover and significant herbaceous groundcover was also observed in Black Pinesnakes in Mississippi (Duran 1998). Conservation efforts for managing Northern Pinesnakes at Arnold AFB should focus on maintaining suitable open-canopy habitats. Pinesnakes would likely benefit from frequent (i.e., every 2 to 3 years) prescribed burning of both pine and hardwood forests. Timber harvesting may also benefit Pinesnakes if it were modified to preserve native vegetative groundcover while leaving stumps to provide adequate microhabitats for snakes. Northern Pinesnakes spent the majority of their time underground (> 85% of observations), primarily using stump holes and concrete foundations located throughout the study area. These structures seem to be important for Pinesnakes, especially where the hardened clay soils are less friable, and should be retained whenever possible. 262 Southeastern Naturalist Vol. 5, No. 2 Sexual divergence in habitat use by Northern Pinesnakes has been reported in New Jersey (Burger and Zappalorti 1989). The differences were attributed to microhabitat preferences used for thermoregulation. Males used more blueberry and less pine and sedge as groundcover than females (Burger and Zappalorti 1989). The sexual differences in habitat use by Northern Pinesnakes in this study could be due to reproductive behaviors. Although a pair of copulating Pinesnakes was found in a young, open loblolly pine stand in late May 2001 (Gerald and Holmes 2004), this hypothesis was not supported since females were not observed ovipositing nor were clutches of Pinesnake eggs found. Further investigations are needed to elucidate reproductive behaviors of Pituophis m. melanoleucus in Tennessee. Most Pinesnakes were observed to hibernate within underground stump holes during this study. In addition, overwintering site fidelity was observed, as two snakes returned to the same hibernacula in consecutive years, and two other individuals hibernated less than 100 m from their overwintering site from the previous year. Pituophis m. melanoleucus in New Jersey typically migrate back to the same den or the general vicinity of their previous hibernacula during autumn (R.T. Zappalorti, pers. comm.). Although up to 30 Northern Pinesnakes are known to share hibernacula in New Jersey (R.T. Zappalorti, pers. comm.), this behavior was not witnessed in Tennessee. Further studies are needed to investigate the influence of current land use practices at Arnold AFB on overwintering and reproductive behaviors of this highly cryptic population of Northern Pinesnakes. Acknowledgments This research was partially funded by Arnold Air Force Base through a contract administered by CH2M Hill. We thank John Lamb and the staff of ACS Conservation for support and field assistance, and Lillian Furlow of CH2M Hill for administrative oversight. We also thank Brian T. Miller and Robert T. Zappalorti for providing comments that improved this manuscript. Additional field assistance was provided by Karan Bailey, Krista Noel, Heidi Kirk, Robert Reed, Jeremy Spiess, and Patrick Ihrie. Robert Schaefer provided assistance with statistical analyses. Additional funding was provided by the Graduate Schools at Middle Tennessee State University and Miami University. Literature Cited Bailey, M.A., K.A. Bailey, J.N. Holmes, G.W. Gerald, and CH2M Hill. 2003. Northern Pine Snake (Pituophis melanoleucus melanoleucus) ecological assessment on Arnold Air Force Base, Tennessee. Unpublished technical project report prepared for Arnold Air Force Base, TN. 66 pp. Blouin-Demers, G., and P.J. Weatherhead. 2001. An experimental test of the link between foraging, habitat selection, and thermoregulation in Black Rat Snakes Elaphe obsoleta obsoleta. Journal of Animal Ecology 70:1006–1013. 2006 G.W. Gerald, M.A. Bailey, and J.N. Holmes 263 Burger, J., and R.T. Zappalorti. 1988. 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