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Tourism in Antarctica has increased significantly over the last 20 years, and predictions suggest this trend will continue (Enzenbacher 1994). The possibility that tourism may negatively affect wildlife populations has thus become an issue of increasing concern to both private and government organizations (Fraser and Trivelpiece 1994), and penguins have likewise become the focus of current efforts to understand interactions between humans and wildlife (Wilson, Taylor, and Barton 1990; Woehler et al. 1994; Fraser and Patterson 1996; Giese 1996). Long-term research undertaken at Palmer Station on Adélie penguins (Pygoscelis adeliae) was recently expanded to include a human-impacts component. Palmer Station is an ideal site for these studies because it is both a favored stop for tourists and the location of two programs that not only have a broad ecosystem perspective focused on the biology of Adélie penguins but also provide background ecological data (see Fraser and Patterson 1996). This article reports the preliminary results of one component of this study for the seasons 1993-1994 through 1995-1996, namely, the relationship between Adélie penguin breeding success and the incidence of visits by tourists.
Our study is based on Torgersen Island, which lies approximately 1 kilometer northwest of Palmer Station ( figure 1). For several seasons, Torgersen Island has been divided into two areas, one open to tourism and the other closed; the latter serves as a control for conducting research in the former. Palmer Station receives approximately 12 ships per season (fewer than 1,300 tourists). Typical visits to Torgersen Island last about 4 hours, and a new group of 10-50 tourists arrives on the island every hour. We monitored tourist visits by censusing tourist numbers and noting their position relative to Adélie penguin colonies every 20 minutes. We then used these data to establish tourism flow profiles that allowed us to rank penguin colonies according to relative use (high, medium, and low) by tourists. Adélie penguin breeding success (number of chicks creched per pair) was determined by comparing breeding sample groups (BSGs) in tourist-visited and control sites. BSGs, each of which consisted of five nests, were randomly placed in colonies throughout the island and monitored daily to obtain data on egg laying, hatching, and chick survival. Between 150 and 200 nests equally divided between the two areas on Torgersen Island were studied each season.
The spatial distribution of tourists during the 3-year study is shown in figure 2. Tourism distribution exhibited a nonrandom pattern; some colonies received disproportionate amounts of activity. As figure 2 indicates, these patterns remained quite constant between years, suggesting that tourists visiting Torgersen Island tend to prefer (for reasons not yet determined) spending more time in some areas than in others.
Seasonal comparisons of the relationship between the number of tourist visits and Adélie penguin breeding success are summarized in the table. Reproductive success was compared using the student's t-test at an alpha level of 0.05. The three-season mean reproductive success for visited areas of 1.53±0.35 chicks creched per pair is significantly higher (t=2.00, df=89, p=0.049) than that for the control sites, where only 1.38±0.36 chicks were creched per pair. Although values for the 1995-1996 season suggest that a large increase in tourists (605 vs. 450 in 1994-1995) depressed reproductive success in the visited sites (1.56±0.28 vs. 1.47±0.38 chicks creched per pair, respectively), this is not the case. Further examination of the tourist-visited areas indicated that in high and medium use areas, mean productivity remained consistent (1.58±0.31 chicks creched per pair) with previous seasons. In the low use area, however, productivity dropped to only 1.08±0.36 chicks creched per pair thus depressing the overall mean for the visited sites.
Factors that potentially influence Adélie penguin reproductive success are numerous and complex (Reid 1968; Wilson et al. 1990; Fraser et al. 1992; Fraser and Trivelpiece 1994). Based on the preliminary evidence resulting from this study, it appears that tourism as it is currently regulated at Palmer Station does not affect Adélie penguin reproductive success. As such, our results diverge from those of Giese (1996) but support the hypothesis (cf. Fraser and Patterson 1996) that environmental factors associated with variability in the breeding habitat (i.e., snow deposition, colony aspect, predation) may be more influential in determining the fate of nesting Adélie penguins than tourism.
This research was supported by National Science Foundation (NSF) grants OPP 93-20115 and OPP 95-05596 to William R. Fraser. Additional support was provided by National Oceanic and Atmospheric Administration/National Marine Fisheries Service contracts to William R. Fraser and NSF grant OPP 90-11927 to William R. Fraser and Wayne Z. Trivelpiece. We are grateful for dedicated field assistance from Brent Houston, Tracey Mader, Laura Somervill, and John Carlson throughout this project. We thank the Antarctic Support Associates staff of Palmer Station for addressing the logistical needs of our project, especially Bob Gowdy and Herb Baker for their exceptional assistance with boating requirements.
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