Human Recreation and the Nesting Ecology of a Freshwater Turtle (Chrysemys picta)

– Over a 3-year period, we studied the relationship between the intensity of human recreation and the nesting ecology of the painted turtle (Chrysemys picta) at a major nesting beach. Our results suggest that the intensity of human recreation at this site had no effect on the decision of turtles to emerge from the water and nest, or on habitat selection by nesting turtles. This apparent lack of effect of human recreation is contrary to the results of many previously published studies on other taxa and underscores the variability in wildlife responses to human recreation and the need for species-specific and population-specific studies. The effects of human recreation on wildlife populations have recently received a great deal of scientific attention, in part because of a rapid increase in outdoor recreation activities over the last several decades (Flather and Cordell 1995). To date, most reported effects of recreation and human disturbance on wildlife have been negative (Boyle and Samson 1985; Carney and Sydeman 1999). However, some investigators have suggested that the effects of human disturbance on wildlife populations may be overestimated (Boyle and Samson 1985; Nisbet 2000), and the impact of human recreation on groups such as reptiles is not well studied (Boyle and Samson 1985). Although declines in populations of organisms such as amphibians (Wake 1991) have been well publicized, concordant declines in turtle populations have received comparatively little attention (Gibbons et al. 2000; Klemens 2000). Although habitat alteration is a major factor in turtle population declines (Mitchell and Klemens 2000), human recreation can also be detrimental (Garber and Burger 1995; Bury and Luckenbach 2002). The potential effects of human disturbance on the nesting ecology of freshwater turtles are significant because females may alter nest-site selection based on the risk that they themselves will be depredated (Spencer 2002; Spencer and Thompson 2003). If females perceive humans as a predation risk and alter their nesting behavior, maternal and offspring fitness can be altered through combinations of a variety of factors. For example, the site where a female chooses to deposit eggs can affect the probability of nest depredation through nest density (Valenzuela and Janzen 2001; Marchand et al. 2002; but see Burke et al. 1998) and edge effects (Temple 1987; Kolbe and Janzen 2002a). Nest-site selection may also affect offspring survival through temperature-related incubation success (Schwarzkopf and Brooks 1987; Wilson 1998) and overwintering success (Weisrock and Janzen 1999), as well as offspring sex ratio in turtles with temperature-dependent sex determination (reviewed in Bull 1983; Ewert and Nelson 1991; Janzen and Paukstis 1991; Shine 1999). The purpose of this study was to determine the effects of human recreation on the nesting behavior of the painted turtle (Chrysemys picta). In particular, we evaluated how different levels of human recreation on a major nesting Appendix II. GenBank and photo voucher accession numbers. An asterisk denotes sequences obtained from GenBank; all but R35 for LAcrm were obtained from Weisrock and Janzen (2000). Photo vouchers are not available for these GenBank specimens, and this is indicated as NA. GenBank accession numbers are given for cytochrome b, RAG-1, C-mos, and R35, respectively, and separated by semicolons for each gene. Alleles for each gene are separated by commas. LAcr1m* NA; AF168766*; DQ529173; DQ529206; AY259581.1* FLer1* NA; AF168751* GAsr* NA; AF168752* ONtr1* NA; AF168757* TXki* NA; AF168759* TXcc* NA; AF168758* TXsc* NA; AF168760*; DQ529147, DQ529148; DQ529185, DQ529186; DQ529125 NMrg* NA; AF168756*; DQ529151; DQ529187; DQ529127 MidCon63 ISUA200614; DQ529103; DQ529157, DQ529158; DQ529192; DQ529122 TC34 ISUA200620; DQ529113 TC35 ISUA200621; DQ529112 TC37 ISUA200622; DQ529111 TC38 ISUA200623; DQ529114; DQ529132, DQ529133; DQ529174; DQ529118 TC36 ISUA200625; EU040193; EU040200; EU040201, EU040202; DQ529119 TC45 ISUA200624; EU040194; DQ529134, DQ529135; DQ529175; no data R35 AM7 ISUA200717; EU040181 AMGst18 ISUA200716; EU040186 AMGst6 ISUA200714; EU040187 AMGst1 ISUA200713; EU040188 AMGst2 ISUA200712; EU040195 LT104 ISUA20073; EU040199 SM102 ISUA20075; EU040189 RM46 ISUA20077; EU040193 RM26 ISUA20079; ; EU040184 RM47 ISUA20076; EU040179 RM106 ISUA20074; EU040192 RM15 ISUA200715; EU040185 RC57 ISUA20078; EU040180 LG28 ISUA200718; EU040182 LIRim15 ISUA200710; EU040191 LGa46 ISUA20072; EU040190 LGa45 ISUA20071; EU040196 LGa25 ISUA200711; EU040197 LGaRim17 ISUA200719; EU040198 NOTES AND FIELD REPORTS 95