Activity Patterns and Habitat Use of Box Turtles (Terrapene Carolina Bauri) on a Florida Island, with Recommendations for Management C

Home , Coccoloba uvifera, Florida box turtle

cheld'ru'rdh"'rdtr(:l,iliifJ:1:;1i ;ff 1;.]J:lt"'

Activity Patterns and Habitat Use of Box Turtles (Terrapene carolina bauri) on a Florida Island, with Recommendations for Management C. KnNNnru Doon, Jn.t't, Rrcrrlnt Funz2, lxo Lonl L. SuIru3

tNationctl Biologic'ctl Suryer, 412 N.E. 16th Avenue, Room 250, Gctinesville, Florida 32601 USA; |Florida Musewn of Naturcrl Histort, (Jniyersin' of Floridct, Gainesville, Florida 32611 USA: sDepartntent of Wildlife utcl Range Science.s, Universit)' of Florida, Gainesville, Floritla 3261 I USA

AssrRAcr. - Egmont Key, located at the mouth of Tampa Bay, has a large population of Florida box tartles(Tenapene carolinubauri) (Cryptodira: Emydidae). From 1991 to 1993, we studied box turtle habitat and substrate use, activity, and the environmental variables associated with more than 1400 captures of over 800 turtles. Most turtles were resting with their heads out when encountered. Activity occurred at air temperatures > 17"C, and turtles were encountered most often at high humidities on sunny days. There were no differences among males, females, and juveniles in air temperature, substrate temperature, or relative humidity at capture site. Turtles are active year- round on Egmont Key. Activity patterns were similar between males and females, but varied seasonally. During cool weather, most adult activity occurred during the warmer parts of the day, but as the season progressed, activity became bimodal with peaks in the morning and late afternoon. Juvenile temporal activity did not change with season. Box turtles used habitats nonrandomly, and season influenced habitat use of adults but not juveniles. Juveniles were found most often in palm- pepper forest whereas adults were more widely distributed, especially on lawns of mown grass. Box turtles congregated around fruiting plants, but cockroaches likely form the most important prey. As Egmont Key is developed as a state park, substantial changes are expected in vegetation structure and composition, and in visitor use. These changes are likely to have a direct impact on the resident box turtle population. Based on our findings, we suggest ways to reduce impacts in order to ensure the long-term survival of this unique island population.

The Florida box turtle, Terrapene corolina bauri, may of Floridabox turtles. On subsequent visits, we marked more 'be considered a common turtle (Dodd and Franz, 1993) in than 800 turtles. Inasmuch as an increase in human activities peninslllar Florida, although little is known of its biology was expected on the island as a result of management rrrher than its distribution and general habitat preferences (including prescribed fire and chemically- and mechani- 1Caff. 1940, 1952 lverson and Etchberger, 1989). Indeed, cally-based exotic vegetation removal) and visitor use, we there are few studies of the lite history of box turtles sollth began a long-term study to monitor the box turtle population t'rl \{aryland (Stickel, 1950, I9l8), North Carolina (Stuart in order to assess impacts. Here, we report data on box turtle f,nd Miller, 1987), Tennessee (Dolbeer, 1969), Arkansas activity and habitat use on Egmont Key, and suggest man- rRea-9an, 1974), and Missouri (Schwartz and Schwartz, agement recommendations to conserve this large popula- I9l4: Schwartz et al., 1984), despite the nearly ubiquitous tion. presence of T. cctrolina in the southeastern United States. Although widespread in Florida, box turtle populations METHODS generally are not perceived to be as large or as dense as populations farther north (e.g., Neill , 1948; Dolbeer, 1969). Studv Site. Egmont Key is a I 80-ha elongate island Carr (1952) stated that the only place Florida box turtles located in the -mouth of Tampa Bay, Hillsborough Co., reached the densities of 7". corolina seen in northern Georgia Florida (21"36'04"N, 82"45'40"W) (Fig. l). The highest \\'as in the limestone flatwoods region west of Homestead in natural elevation is approximately 3.0 m, although most of Dade County, afl area since extensively urbanized. Box the island lies less than 1.25 m in elevation. The substrate turtles have been reported occasionally from barrier islands consists of a combination of compact sand and crushed (Martof, 1963; Jackson and Jackson, l9l0; Blaney,l9ll; shells, with little organic soil except under dense vegetation.

Lee, 1972; Gibbons and Harrison, 198 I ; Conant et al., 1990) The island is surrounded by moderate-energy white sandy and the Florida Keys (Duellman and Schwafiz,I958;Lazell, beaches on the west, north, and south, and generally narrow 1989), but literature references leave the impression that box low-energy beaches to the east. tLlrtles are rare (see above) or absent (Gibbons and Coker, The island has a long history of human occupation 197 8) on islands. (Stafford, 1980; Franz et al., 1992) and island habitats are

In 1 990, we initiated a herpetofaunal survey of Egmont highly modified by the introduction of many exotic plants. Key, Hillsborough County, Florida, prior to the develop- The primary vegetation types include the following (Fig. 1): ment of the island as a state park. During the course of the Sea oats meadows: Sea oats (Uniola panicLtlata) mead- survey (Franz et al .,1992), we discovered a large population ows are located on the southeastern coast and on the overwash Chelonian Consetryation and Biologv, Volume l, lr{untber 2 ( 1994)

on stilts within the TBPA compound. Sea and half 1.. Lighthouse (grass) _srapes flower are found scattered around the law'n's periphery, and 2. Australian Pine occasional small groves of cabba,_ue palm (Sabctl polmetto) 3. Sisal Scrub/Open llabitats are located within it. A shallow depression fills with brack- ish water during periods of heavy rainfall at the reAr of the 4. Palm/Brazilian Pepper TBPA compound. 5. Open Beach Palm-pepper forest: Extensive forests coulposed of a

6. Southeast Sea Oats Meadow mixture of cabbage palm, Australian pine. and Brazilian pepper (Schinns te rebinthiJol ius) overstory dorninate much 7. Pilot's Compound Grass) of the central and southern end of the island. Additional 8. Cross Island Trail patches of the palm-pepper forest are found in the eastern

9. Grassy Swale region of the island. There is generally scant herbaceolls understory, although dense stands of Brazilian pepper can be nearly impassible to humans. Mr"rch of the forest floor is shaded. The ground layer consists of a mixtnre of organic soil, shell-sand,, and loose leaf litter of fallen pahn fronds. Egmont Key is exposed to frequent storms, and vegetation composition may change abruptly in response to wind and wave overwash. For example. the large sea oats meadow on the central western side of the island was replaced by PETERSBURG - extensive areas of bare sand following a series of destructive c)b storms in 1992 and 1993. In parts of the island, especially in the south, nllmerolls shallow drainage ditches have been dug; such ditches are gently sloped, I -2mwide, and less than. m VICINITY MAP 0.5 deep. These ditches fill with water during heavy rains, ,.o., S*,.es as does a shallow swale running south from the TBPA compound (Fig. I ),, and they are frequented by box turrtles during wet weather. Figure 1. Location and habitat of Egmont Key in western peninsu- lar Florida, with vegetation based on a March 1993 aerial survey. Egmont Key is a National Wildlife Refuge leased to the Studies were concentrated on the box turtle population south of the State of Florida for use as a state park. Visitor use is Cross Island Trail. concentrated around the island beaches where more than 1000 boats may anchor on a holiday weekend (R. Baker, plain of the southern part of the west central coast. They are pers. cotrxnx.). Only day visitation is permitted on land except covered by a thick layer of dense grasses (0.5 m in height) at the TBPA. The island is patrolled by rangers from the interspersed with bare areas of compact shell sand. Gopher Florida Park Service. tortoise s (Gopherus polvphenus) make clearly defined path- Twelve species of amphibians and terrestrial reptiles ways through the thick grasses. Clumps of sea grapes are known from the island (Franz et al. , 1992, Smith et al., (Coccoloba uvifera), prickly pear (Opuntia sp.), half flower 1993), including a large population (mean estimate I140, (Scaevola plumieri) and Australian pine (Casuarinct range 700- I 700) of gopher tortoises, Gophe rus polt,phentus equisetifolia) either border or are interspersed within the (Mushinsky and McCoy, 1994). No native mammals are meadow, especially on the southeastern coast. Australian pine groves: Groves of Australian pine (Casuarina equisetifolia) are located on the southern, eastern, and extreme northern tip of the island. These groves are deeply shaded with little or no understory, and are carpeted by a dense layer of fallen needles. Sisal scrub: Sisal (Agave sisalana) scrub occupies much of the central and northern sections of the island, the area most intensively disturbed during the occupation of Fort Dade (Stafford, 1980). In addition to sisal, the vegetation is dominated by Spanish bayonet (Yucca aloifolia), poison ivy (Toxicodendron radicans), palms, and various grasses and small shrubs. Canopy cover is sparse with much bare ground exposed to direct sunlight. Lawn grass: Mowed lawns occur in the vicinity of the lighthouse and in the inholding of the Tampa Bay Pilot's Figure 2. Florida box turtle. Terrapette L'(tntli1711 bttttt'i. resting as Association (TBPA). Turtles find shelter under houses built found on southern Egmont Ke1'. Cltelottiart Consen'atiort und Biologt', Voltune I, Nuntber 2 ( 1994) 99

.:lI :td l, ,l -\- 'i'-

. i,t

.r Il

.' l'l

. -r i ::l'l

..-

: :ll

I l't ;i'l '\. '.{ 3i Fizure 3. Part of a rnoming's catch of box turtles on Egmont Key that had congregated under this single tree of fruiting sea grape. October. 1992.

::'3sent. (Proct,ort although raccoons lotor-) that occasion- photo-eraphed for future recognition, and released. ,,.1r find their way to the island, perhaps released by humans. Dcttct Arrulvsis. The saurpling periods were ._grouped -;il be detrimental to the box turtle poplllation (Franz and into four - seasons for analysis (Jan-Feb = winter. Mar-Apr = )odd. 1993). Domestic cars have been kept ar rhe TBPA spring, May-July = Surnmer, Oct = Antnrnn). The data on - trntpoLlnd; in recent years, some cats have been removed temperatures and relative humidity were tested first for '.', hile others have been neutered to help control the popula- normality. Inasmuch as these data were not normally distrib- ,1trll. uted, the Kruskal-Wallis test was used to test for seasonal Data Box Collectiort.- turtles were collected by visual and sex (males,, f'emales) or life stage (juveniles definecl as < >irlrch during 12 three-day trips in l99l (January, March, I l0 mm CL unless obvious secondary sexual characters (January, rpril). 1992 February, April, Jlrne, october), and [e.g., distinctly concave plastron.l were present) ditferences i993 (April, May, June, July). Collecting was concentrated arnon-q these variables when turtles were captured. The ,-rrr the southern36.4 ha of the island, altholl-qh all parts of the variable 'time' was partitioned into l-hr categories begin- ..lattd were searched several times during the course of the nirrg at 0600. we excluded the month of october I 992from '.tlld)'. Upon capture, the following data were recorded the analysis of the effects of season on tirne of capture Jirectly in the field: carapace length (CL),, plastron length because a large number of turtles (n=90) caught at dawn , PL ). shell depth (SD, taken between vertebral scutes 2 and (0700) prevented Lrs from sampling during most of the 3 t measurements Ishell recorded with a 50 crn caliper to the remaining rnorning hours. Analyses of the categorical data nearest mm]. (using weight a Pesola spring balance to the on capture by sex, life sta.,qe, season, habitat, substrate, and rtearest g)., sex, shell damage, air ancl substrate temperature time were carried out using the Kruskal-Wallis and r rrsin-s an Atkins series 396 digital thermometer), relative Friedman's xl tests, and Lo.,e-Linear Model-Maximum Like- lrurnidity at the turtle (using a Nester RH pen), weather lihood (LLMML) analysis (sAS Institute, Inc., lggz). For conditions, site location, habitat (palm-pepper, Australian LLMML analysis, the model initially was run to tesr for pine. swale, sea oats meadow, sea grape. sisal scrub, lawn, interactions between variables. If no interaction was fbund. other), substrate (shell sand. pine needles, organic soil, leaf the model was rerun and the significance probability was litter. palm fronds, grass), activity (feeding, under cover, determined using the revised values for df and xl. u'alkin..e, resting, other), time captured, and whether the Statistical procedures were carried out nsin_e the SAS turtle's head was in or out. Each individual was given a program for microcomputers (SAS Institute. Inc.. lggg). runique number by notchin..,g the carapace (Cagle, 1939). The level of significance was set at P=0.05. IUU L'lteloruull c'onserl,ctttott ctttcl btolog\:, v otbutrc t, 1\ Lrutucr L \ r ,/.. , /

RESULTS ing hours. Box turtles completely under cover were buried under several cm of leaf litter in depressions left by fallen We collected data from a total of I 448 captures of 8l I palm trees or under dense palm frond litter. Although gopher box turtles on Egmont Key. Not all captures were accompa- tortoise burrows are abundant on Egmont Key, box turtles nied by full data sets, and not all captures were fully were found in burrows only once, on the afternoon of 23 analyzed. April 1993. This was the only time that relative humidities Actit,il'. - The majority (915 of 1360 captures.677c) dropped below 507o during the study and a time when few of box turtles were resting when encountered (Fig. 2). Most box turtles (n= I 3) were observed; only abandoned gopher turtles were on the surface of the ground, were not buried tortoise burrows appeared to be used. beneath leaf litter, and were alert but not moving. In l0l9 of Box turtles were observed eating ripened fruits (prickly I3I7 (777o) captures, the turtle's head was out of the shell. pear, sea grape, half flower, cabbage palm) and cockroaches, Turtles were encountered otten in trails which they con- and one scat that was examined contained several Brazilian strLlcted as they bulldozed through the moist organic soil or pepper seeds. Large numbers of box turtles congregated leaf litter, or they rested in shallow depressions (termed under fruiting plants during early morning hours (Fi.,e. 3); as forms) at the base of grape -eirass clumps or in loose vegetation. The many as 30 individuals were found under a single sea trails and forms were similar to those described by Stickel bush in October 1992. We found turtles also congregating ( 1950) in her study of Maryland box turtles. under fruiting prickly pear cactus, especially during the late In addition to resting, box turtles were found walking afternoon in and adjacent to the sea oats meadow on the (254 captures, I9Vo), completely under cover ( I I I captures, southeast coast; usually two to five turtles were observed at 8Vo)., feeding (63 captures, 57o) or in other activities (17 one time. Cockroaches are extremely abundant on Egmont captlrre s,27o). Box turtles were encountered walking mainly Key and were captured as box turtles bulldozed trails through across the lawn at the TBPA compound during early morn- the leaf litter and surface debris. Individuals also were

observed swimming ( 1 0), drinkin g (2), mating (2), digging ( I ), on its carapace upside down ( I ), in a palm stump hole where it had fallen ( I ), and resting over a recently completed N-152 N:248 ffi ggo ffi nest (2005 h on l7 June 1993). RWr.l{Ht o [ssi#+t f Kt,WI Environnrcntal Conclitions. Most box turtles were ,U tsirii9.ll;jt ffiffi 6 ftH*r#ftllN captured under clear,, sunny skies- (780 1356 captures, &zo Bffis- ffiffinffi-ffi of rv,!2.:x{ta 24.O E 1t9.tl:lHr 27.3 24.3 22-29 587o), although turtles were captured under a variety of other P 21 -36 L 21.O 19-31 3.4 2.O weather conditions., including cloudy (3 l0 capture s,237o), 17-30 2.4 2.9 partly cloudy (226 captures, ll%o) and rainy (40 captures, 37o). Box turtles appeared to be most active following Winter Spring Summer A,r.rtumn rainfall, especially after dry weather. Box turtles were captured at air temperatures ranging N: 54^ from l7' to 36"C, substrate temperatures of l6' to 42"C, and 0 I!t!!E!!|ftl or 40 EK+i:*ffi = relative humidities of 247o to 947o (Fig. 4); turtles were not (g N:163 N:242 ffi N:124 h\ti:;:;:::;:l:F.l captured below these temperatures despite searches during tso llttl:11:rhu E F..i':&i*:ffl llHP.S.f'11 P IiS$i'iFIi;l D:1...'Xf.rail- FRfuXfl EErEaEsi cooler weather. The high substrate temperatures were en- Elirr'itiC{.::'il ffi-ffi FSffii$J E2o at44li$diil ag t l:ifi.:i.lsH 24O F EEIS$tilS 26-7 countered as the box turtles walked across bare shell sand in v, 22.A 22-30 -ct 1 9.1 21-42 18-29 A 1o 16-31 3.3 2.O the late afternoon on hot summer days. The air temperatures 2.2 1.8 (x2=389.87, df=3, P=0.000 I ), substrate temperatures Winter Spring Sumrner AutJmn Table 1. Loglinear Model-Maximurn Likelihood Analysis of the effect of season on time captured,by sex (ntarle. f-emale) and life 1@ N: 4O4 (juvenile). (<0.05) ffi stage A significant P indicates that values are HffiS!lwlS not uniformly distributed. t80 N- 76 ffi- E }^Vd ffi!:(':rrlsv.:fl E' F-::l;iitt:lt Comparison df \- 'E t+,H#.'d.f- 60 F.':{4a bkb! ffiEftthq..z.:rg Eititi:illii! E#-id'HIf, -ot Males P.':9,itl:{':nt811'-#t 76..7 ;40(o t{

, ,t her between season and habitat differed between males and llfT ), juveniles (Table 2). but the basic overall patterns of habitat

:;I I'C S. use were statistically similar (Kruskal-Wallis test, x2=64.4. .,,, ill_g ""b df= l., P=0.0001 ). Time (1 hr intervals) During the winter, box turtles were observed most oflen

Figure 6. Temporal activity ofjuvenile box turtles on Egrnont Key. in the palm-pepper forest 1Fi,_e. 7). With the wanner tempera- S-i.i\Lrn had no effect on juvenile temporal activity. tures of spring and sumrner, however, adults increasin-ely were found on the lawn at the TBPA compound. During the rl=552.85, df=3, P=0.000 l).' and relative humidities autumn when sea grapes were fruiting, the concentration of rr=7 1.67, df=1, P=0.0001) at which box turtles were cap- box turtles around sea grapes increased dramatically. The :ured varied significantly among seasons. However, we main difference between adult habitat use also occurred in Jetected no difference among males, females, and juveniles autumn when male use of the palm-pepper forest decreased irr rerms of the air temperature (x2-4.45, df=Z' P=0. 1l), in relation to female use of the forest. Juveniles for the most :ubstrate temperature (x2=4. 12, dt-Z. P-0. 13). and relative ' the lrrrrnidity (x2-4.87, df--2, P=0.09) at which turrles were Table 2. Loglinear Model-Maximum Likelihood Analysis of the lit'e effect of season on the habitat where the turtle was captured. by ser .-- irptured. ,are (male. female) and life stage (juvenile). A significant P (<0.05 t Tin'te Cupturecl. - Nearly all turtles were captured f rom indicates that values are not r-rniformly distributed. davu'n until dusk. During winter, this resulted in an 0700 to 1 P Comparison df X- 1700 h EST activity period which gradually shifted to 0600 to 2000 h EDT in summer. Only five of I 448 box turtles were Males r1.00 captured after sunset, despite casual searches on most nights Season 3 21 .86 0.00 () Habitat 5 t7 5.46 0.00 00 island, were 000 that we were on the and those five turtles active Season'l'Habitat t4 t65.96 0.00 at approximat ely 2145 h on 27 Jtrly 1993 during a heavy rain Females 000 shower. Season 3 6.19 0. l0 (t.00 Habitat 5 17 .48 0.00 Male and female box turtles used time in a nonrandom (J.00 Season'i'Habitat ll 8t .84 0.00 fashion that was influenced by season, although juveniles Jr-rveniles (J.07 \\'ere captured fairly uniformly with respect to time of day Season 3 29.00 0.00 0. l5 Habitat 4 l3 l .04 0.00 re-eardless season (Table There was significant 067 of l). no Season'l'Habitat 6 3.29 0.ll ditference between male and female patterns of time use Winter Spn ng

80 160 f,] vtates B rem ales I uuvenites

ct, 70 cn 1N (2431 (1 (60) o) (D 43) 60 120. E F 100 o 50 o o) N C) 80 -cr -o E E J 30 60 z z, 20 40 10 20 o o PaPe Pine Swale SeOM SeGr G rass Pa Pe Pine Swale SeOM SeGr Grass H abitats H abitats Summer Autumn 2o,o- E vtales ffi eem ates I luveniles Ervrales ffiFe-ales I;.rvenites (73) (60) (6) 3n (31 (41 (D 7) (2231 ) 150 U' F E2so) ra- o F q) 100 E20 -o o) E c 15 E z.= 50 z,= 10 5

o O PaPe Pine Swale SeOM SeGr Grass PaPe Pine Swale SeOM SeGr Grass H abitats H abitats

Figure 7. Seasonal variation in habitat use of box turtles on Egrnont Key. PaPe = Cabbage palrn-Brazilian pepper fbrest. Pine = Australian pine groves. Swale = grassy swale on south of island. SeOM = sea oats meadow. SeGr = immediate vicinity of sea grape bushes. Grass = Srass! lawn at the TBPA compound. part remained in the palm-pepper fbrest and only infre- time of day in which they were active (Fig. 8), even after quently ventured into other habitats, mostly during the adjustingfortheeffectsofseason(Friedman'stest,x?=378.5, summer. df=5. P=0.000). The lawn at the TBPA compound was used Box turtles used habitats differently with respect to the mostly during the early morning hours. The peak of morning

ffiil swate I pine N seGr ffi seoM Zcrass I paPe

120

U' 100 o # l- 80 F tF o 60 ol- -o N 619 E 40 - J N-426 z N :99 20 N :60 N :57 N=52 3,

Figure 8. Temporal variation in habitat use by box turtles on Egmont Key. PaPe = Cabbage palm-Brazilian pepper tbrest. Pine = Australian pine groves. Swale = grassy swale on south of island. SeOM = sea oats meadow. SeGr = immediate vicinitt, of sea grape bushes. Grass = grass! lawn at the TBPA compound. Chelonicut Consen'atiort and Biologr, Volunte I, lVuntber 2 (1994) r03

160 200 a 140 a o = 120 1sOi J 100 . E I

I o 80 o 1001 c) 60 c) -o 40 E )= f, 50 z 20 z o N: 140 Sand PiNe Soil LeLi PaFr Grass Sand PiNe Soil LeLi PaFr Grass _l I Autrmn I wnter Spring Suveniles I Females '] vrales Figure 9. Sr"rbstrate use bv box turtles on Esnront Ke)'during the Figure 10. Variatiott in substrate use by box turtles on Egrnont Key n itttet'. sprin-e and autllmn. No difterences erist betu'een the sexes durin-e the sulnr-ner. Sand = shell sand. PiNe = Austialian pin-e ,rt'between juveniles. adults and Sand = shell sand. PiNe = Austra- needles. Soil = organic soil. LeLi = leaf litter. PaFr = whole or .iart pine needles. Soil = of-e&nic soil. LeLi = leaf litter. PaFr = ttearlv etttire palnr fronds. Grass lawn at the TBPA com- ''r = -srass httle ornearly entire palnr fronds. Grass = lau'n grass at the TBPA pound. -trlllPOUlld.

.rctivity amon-g the sea .-grapes resnlted trorn data collected in needles. or-sanic soil. and leaf litter (Fig. 9). In the spring, October 1992 when the sea srapes were fruitin_e. Use of the they shifted to leaf litter and a -srass. pattern maintained in the .3it oots meadow differed seasonally. with lnornin_e activity autumn (Fi-e. 9 ). During these seasons, the patterns of . n the winter AS sunli._eht warmed the open _9round. and substrate use did not differ significantly among males, etritr-9 .. i;rn :r octivity in the sumnter as the slln went down behind femarles. and jur,'eniles (Table 4). In the surnmer, however, IJ: S ,' line of tall Australian pines. The use of palm-pepper forest the patterns of sr"rbstrate use between adults and juveniles (see -'ir-rsely followed -general activity patterns above). chan-eed si.-enificantly from that of the other seasons (Table Substrote .l). :ter Llse. Box tnrtles were tound most coln- Males were found slightly more otten on pine needles and :rrrnl\/ (432- on -grass of 1345 captures. 32%). fbllowed by sand than females. Juveniles. however, alrnost were never .:rf litter (288 . zlt/r). organic soil (250. l9%). Anstralian found on --i -grass substrates but frequented organic soil and leaf :irre needles (171, ( ine l3 7r). shell sand 120. 9%). and whole litter (Fi,_e. l0). :.rlrn tronds (49,4Vc). The remainin,_e 29 turtles were found l, \\ Ater. of whichz3 were captured in April lggzafter heavy DISCUSSION .'.:ins: box tr"rrtles found in water were not considered in the --:ti-rlr sis of substrate Llse. Box turtles on Egrnont Key appear to lead a rather \'lale. fernale, and juvenile box turtles did not Llse sedentary life centered on locating food, shelter during - ..b.trates uniforrnly (Table 3 ), and adult substrate use unfavorable periods of heat, cold, and hurnidity, and repro- ri'ied seasonally, althou._qh juvenile substrate use did not duction. Most of the day is spent restin-9 in forms ortrails on Table 3). In winter, turtles were found primarily on pine the surface, or, when weather becomes excessively hot or cold, buried under leaf litter. Peak activity is correlated with warm temperatures, high humidity, and rainfall, and habitats Table 3. Lo-elinear Model-Maxirnr,rrn Likelihood Analysis of the that supply these optimum requirements are used on a daily =::ect of season on the substrate where the tr"rrtle was captured.by -3\ ( ttiule. fernale) and life sta-ee (juvenile).A si-enificant P (<0.05) or seasonally varyin.-e basis. Most activity occurs durin-e :..iicates that values are not uniformly distriburted.

1 -.,)nrpill'ison df X- Table 4. Comparison of seasonal substrate use among sexes and life stages. Cornparisons used the Kn-rskal-wallis test. \ Iele: 1 Season J 100.49 0.00 Comparison Season xl df p Sr-rbstrate 5 38.r7 0.00 Season':'S ubstrate t4 150.77 0.00 Male vs Female All Seasons 4.63 0.03 Fenriiles Male vs Juvenile Winter 0.33 -l 0.56 Season J 73.90 0.00 Spring l.9l 0. l6 S ubstrate 5 63.7 5 0.00 Summer I 3. 13 0.00 S Season'k ubstrate l5 r03.33 0.00 Autumn 0.26 0.6 r J -rr eniles Female vs Juvenile Winter 0.00 0.93 Season 3 32.44 0.00 Spring 0.65 0.-12 l.lll Sr"rbstrate 5 46.50 0.00 Summer 24.31 0.00 ;:S Season'i'Substrate lt 1t .94 0.37 Autumn l.l4 0.29 ffi

r04 Cltelortiun Cottservutiort rutcl Biologt', Volume l, llunrber 2 ( 1994) early morning hours. especially during the sLlmrner and reported for box turtles throughout their raltse (Stickel. autumn when turtles congregate to feed on ripened fruits. In 1950: Dolbeer. 1969, Reagan. 1911: Maclden. l9l5 t. Field terms of their activity, Florida box turtles on E'emont Key act ambient ten-rperatures are closely correlatecl u ith bocll' tent- much like the northern subspecies of L c'urolirla (Stickel. perarture in box turtles (Adams et arl.. 1989 ). 1950; Dolbeer,, 1969; Reagan. 1974, Madden. l9l5). al- Nearly all studies of box tr"rrtles foclrs on adults because though their activity extends thron-ehout the year (Carr. the juveniles and yoLln-g are nearly impossible to find. On 1952; this study). Egrnont Key, however, juveniles comprised 15.3 clL (114 of The use of gopher tortoise burrows by T. c'urutlirlrr has 8l I )of our sarnple and l07c of all captures. Hence. substan- been reported in a few other str-rdies (review in Jackson and tial data were available to allow examiuation of difterences Milstrey,, 1989: Bretndt et al.., 1993), and box turtles occa- in habitat use between adults andjuveniles. Trencls in habitat sionally use mammal burrows for hibernation (Ernst and Llse, substrate use, and tirne of activity differ betr,r'een.iuve- Barbor"rr,, 1972). However, on Egmont Key. box turtles seen-l niles atnd adults. although the magnitucle of the difference to use only abandoned tortoise burrows and then only durin_9 varies seasonally. rnuch spatial and temporal ol'erlop occLlrs. periods of low humidity. Box turtles appear to be sensitive and no differences exist among the environrtrental variables to low hurnidities. For example. Bo-9ert and Cowles ( I 947 ) recorded at citpture. Juveniles tend to preterentially inhabit reported that a female Florida box turtle lost ll .3% of her areas with abundant or-qanic soils and -gronnd cover. espe- body weight during a 45-h period at a ternperature of 38"C cially the palm-pepper forest, and are rather uniforrnly and a relative humidity of 37%. Rea_ean (1911) also noted a active throughout the mornin-g re-gardless of seAsolt. Several preference for high relative hurnidities (857c) by Arkansas reasons zlre possible tor differences in habitat Llse. incluclin_u box turtles. Others have noted a seemin-9 preference for high a greater abutrdance of small prey. covel' sites (from both hurnidities, but without quantification (e.._e.. Stickel, 1950), environmental extremes and predators). and ntore thermal or that box turtles become inactive during dry periods stability in the closed canopy forest than in the open habitats. (Stran-e, 1983). The use of gopher tortoise burrows durin,_9 Although the Australian pine forest ntay otfer thermal stabil- low humidities is probably opportunistic, but may be par- ity, turtles are very conspicLloLls on the dark needles and prey ticularly advantageous on parts of the island lackin_e deep abundance is probably less than in the palrn-pepper forest. organic soil or leaf litter. The pine needles also form a dense carpet that snrall tr.rrtles Box turtles are omnivorous, eating a wide variety of may find it difficult to bury into. fungi, plant material., insects, and carrion (Cahn, 1937; Carr, 1952; Klimstra and Newson-re, 1960: Stuart and Miller. Management Recommendations 1987). Elsewhere, they are reported to congregate under fruiting plants (Klimstra and Newson-le, 1960; Dolbeer. The interior of Egrnont Key has had little human inter- 1969) as they do on Egmont Key. Fruits are likely imporrant vention since Fort Dade was abandoned in 1921 . Humarn seasonal sources of both food and moisture, especially since activities -generally have been conflned to the TBPA com- fruits may be abundetnt durin'e the autumn. the driest tirne of pound. the li-ehthouse area in the north, and the surroundin.-g the year in central Florida. On Egmont Key however. the beaches. With the developrnent of the island AS a state park. primary food solrrce is likely to be the hu.-ee popr-rlations of however, patterns of hurnan use may chan_9e. State park cockroaches that inhabit virtually every part of the island. policies call for management protocols that will return parks Raking throu-eh the leaf litter reveals hoards of cockroaches., to the vegetational composition that existed prior to Euro- but few other invertebrates. Or-eanic soils are fairly shallow, pean settlement. On E_emont Key, a sLlrvey in 1876 noted and the remainin-e substrate is composed of compact shell that the island was "...sLlrrounded on all sides by a smooth sand where relatively few invertebrates are found. beach, and is mostly. first rate cabba-ee hammock and prairie On Egmont Key, box turtles neither hibernate nor go with no mangrove" (Franz et al.. 1992). An 182 I letter into an extended period of summer inactivity. Instead., activ- reported that live oak hammock occurred on the island. "C ity is rele.-eated to periods of f avorable temperatures (> I 7 ) althou..gh evidence of such a forest no lon-9er exists. It is "natLrrAl" and humidity. Dr"rrin-9 the cooler months of the year, activity theref ore unclear as to what the Ve _eetation of is rather evenly spaced dr-rrin-9 the day, and gradually shifis E-9mont Key was prior to European settlenrent. and if flre toward the morning hours as temperatures rise. In the sllm- forrned an important component of the ecosvstenr. mer, most activity stops during the hot afternoon as the Management plans call for the removal of exotic \/e_g- turtles seek shelter in the cooler or._ganic soil and leaf litter. etation using both mechanical and chernical nteans. Work Habitats providin-e favorable temperature and humidity con- has begun to clear the stands of Brazilian peppel' and Austra- ditions are used accordingly. e.g.,, open meadows are used in lian pine. In addition, park personnel plan to beein r,rsing the winter or late in the day in summer when they are no prescribed flre in 1994 to thin wood\' \'esetation and reduce longer exposed to direct sunlight. In the hot months, turtles presently hi-eh fuel loads. Scars on palnr trees shou that fire frequent the palm-pepper forest that provides high humidity, has burned parts of the island in the past. Sonre bor turtles relatively cooler air, and cooler substrate temperatures in also show extensive fire scars on their carapilce. Hou'ever, which to bury themselves. Seasonal shifts in habitat Lrse, the origin of these fires is unkno\\ n. presllmably in response to moisture and temperature, are The levels of visitor use throlrshout the i:land are not Chelonian Conservation and Biology, Volunte l, Number 2 (1994) 105

projected to increase with the development of the historical Chemical elimination of exotic vegetation should not be - aspects of the park (R. Baker, pers. comm.). Park-related conducted, unless the herbicide is injected or otherwise facilities may be constructed (primitive campsites primarily directed only at the target tree. Spraying should not occur tor small groups of special-interest visitors, restrooms, ranger when Brazrhan pepper is fruiting . 2) A firm rationale for residence, and a visitor center); these will be concentrated in using fire as a management tool needs to be developed, the northern one-third of the island. A tour boat landing zone especially in the absence of data on its historic occurrence u'ill encompass the northern end of the island. A shore bird and importance. Fire may notbe appropriate if mesic or xeric protected zone is designated on the southern tip of the island, hammocks are the desired vegetation types. If fire is used in bnt this area is not used by box turtles or gopher tortoises. management, initial burns should be conducted durin_e the \lthough Park and refuge personnel are aware of the signifi- winter at a time of low wind speed and high humidity in order carlce of the turtle population on Egmont Key, future man- to ensure a cool fire. If fuel loads are deemed too high to ;'rsernent plans must address their biological requirements. conduct a cool fire, a head fire under windy conditions would If management proceeds as anticipated, the vegetation pose the least harm to buried box turtles. In order to ensure :tructure of Egmont Key will change substantially. At least turtles are buried as deep as possible, burns should be t'rn a short-term basis, removal of exotic vegetation and conducted during or immediately after a period of cold pre scribed burning will increase sunlight reaching the forest temperatures. If summer burns are used, they should occur l-lt-ror with a concomitant increase in temperature and a in late afternoon on days with low humidity. 3) Burns should Jecrease in humidity. Opening the canopy will expose the avoid impacting fruiting plants, especially prickly pear, sea ntt-rist organic soil to the direct effects of wind, increasing grape, and half flower, as much as possible. Burns should not 3\ aporation and exposing soil to erosion caused by severe be conducted when these important food sources are fruit- titunderstorms. A hot spring or summer fire is likely to not ing. 4) Small plots should be burned rather than simulta- ,rrtlv elirninate the leaf litter used by box turtles, especially neously burning a large section of the island. 5) The restora- ihe smaller size classes, but also to result in substantial direct tion of the vegetation community should include planting rrrtrrtality (Babbitt and Babbitt, 195 l;Can,1952) and sub- native oaks and cedars as soon as possible to compensate for :tantially reduce the cockroach population. canopy removed during exotics control. 6) Surveys should In addition to direct impacts from altering the vegeta- be undertaken to determine impacts from site location of trtrn structure, visitor use and allowing overnight stays on the visitor facilities on all native species, especially the turtles, i.land may result in the illegal collection of turtles and rattlesnakes. and unique mole skink (Smith et al., 1993), Itrrtoises, especially the attractive small size classes which prior to construction. Visitor facilities should not be located lre so conspicuous on Egmont Key. Current Florida law in hi-eh density turtle areas .1) Camping should be allowed ullou's possession of two box turtles, although animals are only under ran-ser supervision. Camping should not be rtt-rntinally protected on the island. However, once off the allowed in areas of high turtle use. 8) Pets should not be i.land. there is no way to ensure that the turtles did not come permitted on the island. Existing cats in the TBPA com- irom Egmont Key. Visitor use also might impact activity pound should be removed and if raccoons are found on the patterns., especially of the gopher tortoises, and increase the island, they should be removed. 9) Visitors should be given ptrtential for the introduction of mammalian predators. brochures concerning the protected status of native plants Terrapene carolina generally is perceived to be a com- and animals, especially the box turtles and gopher tortoises. nlorl species in Florida although no studies provide data on Visitors should be advised not to approach or handle turtles. population size or status, and many threats are present (Dodd Signs should reinforce this information. 10) Because of the and Franz,,1993). Within Florida, the Egmont Key box turtle high price of box turtles in the international pet trade, park population may be unique because of its large size resulting personnel should be especially vigilant on Egmont Key. from its isolation from the mainland, the absence of mamma- Poachers should be dealt with severely. I I ) Finally, we lian predators, and the large number of cockroaches which recommend that a long-term program be set up to monitor serve as a prey base. Little or no predation has resulted not the Florida box turtles and gopher tortoises on Egmont Key onlv in large numbers of all size-classes, but also in their in order to ensure the survival of these unique island turtle general conspicuousness. Dodd and Franz (1993) point out populations. that common species may not be as common as perceptions indicate, however, and that management protocols need to Acknowledgments take them into consideration. Consideration also must be directed at the timing of various management actions. While We thank Robert and Betsy Baker and the park ran-eers \\ e prefer ecosystem management over individual species at Egmont Key State Park for their friendliness and generous nrana..sement, we believe that the large turtle populations on assistance with transportation; Cameron Shaw Egmont Key can and should be maintained as restoration (ChassahowitzkaNational Wildlife Refuge) for permission proceeds. to work on Egmont Key and use Fish and Wildlife Service We make the following suggestions to reduce impacts housing facilities on the island; and Shelley E. Franz.Ehza- rrn tllrtles from vegetative restoration and development of beth Knizely, and Tom Leuterrtz for field assistance. Bob the island for its biological and historical attributes. 1) Baker, John Iverson, Dale Jackson, and Henry Mushinsky 106 Chelonicut Conservcttion ancl Biologt, Volume I, Nuntber 2 t 199: offered helpful comments on the manuscript. DauphinIsland.Alabanra.Qrrar.t'J.F....*-

281 . LITERATURE CITED JncrcsoN. D.R. AND E.G. MtlsrRE\. l9:.'' T..: . ---. .--- ^ Jrrpher tortoise burrows. In: Diemer. J.E.. D.R. J,.r.-.- . . .' L;ttders. J.N. Layne. and D.A. Wood (eds. ). Gophei' T, :-. .: R.:ir'rc.riot't AoRvs, N.A.. D.L. CuussEN, AND J. SKTLLTNGS. 1989. Effects of Symposium Proceedings. Florida Nottslinte \\ .* Te;h. Rep. temperature on voluntary locomotion of the eastern box turtle. 5 : 86-98. Terrapene corolina carolina. Copeia I 989:905-9 15. Klrusrnn. W.D. AND F. NEwsoME. 1960. Sotne t-rb.,rr'\.r.iitrn: otr the Bassrrr, L.H. AND C.H. Bneerrr. 195 I . A herpetological study of food coactions of the common box tr-rrtle' Te rru1" ttt t ' t'ttt'ttlirtct ' burned-over areas in Dade County, Florida. Copeia 195 I:79. Ecology 4l:639-641 . Br-eNEv, R.M. I9l l. An annotated check list and bio-9eo-eraphic Lazett, J.D., JR. 1989. Wildlife of the Florida Ker s: A \atr"rral analysis of the insular herpetofauna of the Apalachicola re-eion. History. Washin-qton, D.C.: Island Press. 254 pp. Florida. Herpetologica 2l :406-430. LEE. D.S . 1912. List of the amphibians and reptiles of AssateagLre BocEnr, C.M. AND R.B. CowlEs. 1947. Moisture loss in relation to Island. Bull. Maryland Herp. Soc. 8:90-95. habitat selection in some Floridian reptiles. Arn. Mns. Novitates M,rooEx, R. 1975. Home range. moverlents. and orientation in the 1358:l-34. eastern box turtle. Terrupene c'arolirrct c'urolina. Ph.D. thesis.. BnnNnr, L.A., K.L. MoNrcoMERy. A.W. SruxoEns. ,{\D F.J. City Univ. of New York. Mezzotl. I 993. Life history notes: Goplrcrus polt'plterttus (Go- Mrnrop. B.S. 1963. Some observations on the herpetofauna of pher Tortoise). Burrows. Herp. Rev .21: l-19. Sapelo Island. Georgia. Herpetologica I9:10-72. CncLE, F.R. 1939. A system for markin-s turtles for future identifi- Mr-'snrrsK\'. H.R. AND E.D. McCov. In press. The status of gopher cation. Copeia 1939:ll 0-112. tortoises. Gophenrs polvphentus, on twenty State and Federal CRurlr, A.R. 1937. The tr"rrtles of Illinois. Illinois Biol. Monogr. l6: l- Bury. R.B. and D.J. Germano (eds.). Biology 2t8. lands in Florida. In: of North Arnerican Tortoises. National Biological Survey Re- CeRn, A. 1940. A contribution to the herpetology of Florida.Univ. search Report. Florida Publ. Biol. Sci. Ser. 3: l- I 18. NETLL. W.T. 1948. Odor of young box turtles. Copeia 1948: 130. Cnnn, A. 1952. Handbook of Turtles. The Turtles of the United REncnN, D.P. 1974. Habitat selection in the three-toed box turtle. States, Canada, and Baja California. Ithaca, N.Y.: Cornell Univ. Terrapene corolina triungui.r. Copeia 1974:512-527 . Press, 542 pp. SAS INsrrrurE, INC. 1988. SAS/STAT user's guide. Release 6.03 CoNnNr, R., J.C. Mrrcsell., AND C.A. PncuE. 1990. Herpetof auna of edition. Cary, North Carolina: SAS Institr"rte. Inc. the Virginia barrier islands. Virginia J. Sci . 4l:364-380. SAS INsrrrurE. INC. 1992. Categorical data analysis course notes. Dono. C.K.. JR. AND R. FnnNz. 1993. The need for status informa- Cary. North Carolina: SAS Institute. Inc. tion on common herpetofaunal species. Herp. Rev . 24:41-50. ScHwnnrz. C.W. AND E.R. ScHwnnrz. 1914. The three-toed box DoLsEER, R.A. 1969. A study of population density, seasonal tr-rrtle in central Missor"rri: its population. home ran,ge. and rrovelnents and weight changes. and winter behavior of the movements. Publ. Missouri Dep. Conserv. Ten. Ser. 5:l-28. eastern box turtle. Terrapene c. carolina L., in eastern Tennes- Scuwnnrz. E.R., C.W. Scuwnnrz, AND A.R. Ktpsren. 1984. The see. M.S. thesis, Univ. Tennessee,, Knoxville. three-toed box tr"rrtle in central Missouri. Part II: A nineteen-year DuellvnN, W.E. AND A. ScnwARrz. 1958. Arnphibians and reptiles sturdy of horne range. movements. and popurlation. Publ. Mis- of southern Florida. Bull. Florida St. Mus. Biol. Sci. 3:l8l-324. souri Dep. Conserv. Terr. Ser. l2:l-29. ERxsr, C.H. AND R.W. Bnneoup.. 1972. Turtles of the UnitedStates. SvrrH. L.L, R. FnnNZ, AND C.K. Doon. Jn. 1993. Additions to the Lexington: Univ. Press of Kentucky,, 347 pp. herpetofauna of Egrnont Key. Hillsborou-eh Cournty. Florida. FRANz, R. nNp C.K. Dopp. Jn. 1993. Raccoon predation on Florida Florida Sci. 56: 23 I -234. box turtles at E-emont Key, Hillsborough County, Florida. Florida Srnnponn, J.W. I 980. Egmont Key: sentinel of Tampa Bay. Tarnpa Sci. 56(Suppl. 1):23. Bay Hist. 2(I):15-29. FRRNz, R., C.K. Doon, JR., AND A.M. Bnno. 1992. The non-marine SrrcrEr-, L.F. 1950. Popr"rlations and home ran-se relationships of herpetofhuna of Egmont Key, Hillsborough County. Florida. the box turtle, Terrapene c. cctrolirtct (Linnaer,rs ). Ecol. Monogr. Florida Sci. 55 :179- I 83. 20:351-378. GteeoNs, J.W. AND J.W. CorEn. 1918. Herpetotaunal colonization SrrcrcEl. L.F. 1978. Chan-ees in a box tr,rrtle population dr"rring three patterns of Atlantic Coast barrier islands. Am. Midl. Nat. 99:219- decades. Copeia 197 8:221 -225 . 233. SrnnNc, C.A, 1983. Spatial and temporal actir it1 patterns in two Gresoxs, J.W. AND J.R. Hnnnrsox, III. 1981. Reptiles and amphib- tenestrial tr,rrtles. J. Herp. l7:43-47 . ians of Kiawah and Capers Islands, South Carolina. Brirnleyana Srunnr. M.D. AND G.C. Mrr-r-En. 1981. The eastenr bor turtle, 5.145-162. Terrapene c'. carolina (Testudines: Em1 didae ). in \orth Caro- IvEnsoN, J.B. AND C.R. ETcHSERGER. 1989. The distributions of the lina. Brimleyana l3:123-1 31. turtles of Florida. Florida Sci . 52: I l9- 144. JncrsoN, C.G..' Jn. AND M.M. Jncrsox. 1970. Herpetofauna of Accepted: 23 March 1994