Our L/\ i/ji; Rcsruirccx — Kcpliles and Amphihums 



119 



Documenting Turtle Population 

 Status 



1 ie\iev\ed the population trends of turtles in 

 the United States by examining most references 

 (Ernst et al. 1994) that document the trends of 

 tuitle species and populations. Because few 

 long-term studies (lasting more than one gener- 

 ation of the species examined) have focused on 

 turtles, data on population fluctuations over 

 time are generally unavailable (but see Gibbons 

 1990; Congdon et al. 1993). Techniques for 

 conducting population studies of turtles and 

 analyzing the data are summarized in Gibbons 

 (1990). ^ 



Although we know less than desired about 

 the actual extent of population fluctuations in 

 most turtle populations, we do know that many 

 turtles in the United States are at great risk of 

 decline and extinction. Of the 55 native turtle 

 species in the United States and its offshore 

 waters. 25 (45*7^) require conservation, and 21 

 (38%) are protected or are candidates for pro- 

 tection under the Endangered Species Act. Of 

 the 1 1 species and subspecies listed as candi- 

 dates for protection under the ESA. 4 are con- 

 sidered declining, and 7 have unknown popula- 

 tion statuses (Table). All tortoises and marine 



turtles require conservation action. Of the 

 remaining 46 turtle species (aquatic and semi- 

 aquatic fornis), 16 (35%) require conservation 

 action. The percentage of U.S. turtles requiring 

 conservation action (45%) is similar to that of 

 the world (41%; lUCN/SSC Tortoise and 

 Freshwater Turtle Specialist Group 1991 ). 



Although no turtles in the United States are 

 known to have become extinct since European 

 colonization (Honegger 1980). many species 

 have experienced significant declines in num- 

 bers and distribution during the last 100 years. 

 For example, several bog turtle (Clenunys muh- 

 lenhergii) populations in western New York, 

 and all populations in western Pennsylvania, are 

 apparently extirpated (Collins 1990; Ernst et al. 

 1994). Some populations of the spotted turtle 

 (C guttata} have also shown dramatic declines 

 (Lovich 1989). Even wide-ranging, formerly 

 common species such as the common box turtle 

 (Terraiieue Carolina: Ernst et al. 1994). desert 

 tortoise {Gopherus agassizii: USFWS 1993). 

 gopher tortoise (G. polyphemiis: McCoy and 

 Mushinsky 1992), common slider {Trachemys 

 scrlpta: Warwick 1986). and the alligator snap- 

 ping turtle {Macwclemys tewwiiickii: Pritchard 

 1989) have declined significantly, underscoring 

 the importance of monitoring "common" 



Table. U.S, turtle species in need 

 of conservation. 



C^ ~ Possibly qualifying for threatened or endangered status, but more information is needed for determination. 



