Literaturdatenbank
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Brisbin, I., Kennamer, R. A., & Peters, E. L. , Findings along the way: what we learned (and have yet to learn) after 18 years of radio tracking box turtles in a suburban neighborhood. Paper presented at Third Box Turtle Conservation Workshop.
Added by: Admin (14 Aug 2008 20:33:42 UTC) |
| Resource type: Proceedings Article BibTeX citation key: Brisbin2007 View all bibliographic details  |
Categories: General Keywords: Emydidae, Habitat = habitat, Nordamerika = North America, Schildkröten = turtles + tortoises, Terrapene, Terrapene carolina Creators: Brisbin, Kennamer, Peters Collection: Third Box Turtle Conservation Workshop |
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| Abstract |
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We report data collected by the radio tracking of adult eastern box turtles (Terrapene carolina carolina) in an urban forest/suburban neighborhood ecotone in Aiken, South Carolina. These data span a period of more than 18 years and are still ongoing, possibly the longest continuous radio tracking data ever collected for any wild animal. This study has produced information on turtle survival characteristics in these areas and interactions of the turtles with humans and conspecifics. Information gathered during the first 15.5 years of the study, representing over 125 individual turtle-years, has been written-up in a manuscript which is currently in press and the results are summarized here: constant annual adult survival probability estimated for radiotelemetered turtles was 0.932 + 0.021 (SE), with females experiencing lower survival than males. There was a suggestion that greater time spent in suburban neighborhood habitats tended to reduce survival. An independent estimate of constant adult survival, derived from the opportunistic marking and recapture of 86 non-telemetered turtles in the same study area was 0.954 + 0.036 (SE). Even though the population was male-dominated (male:female = 2.1:1), the encounter rate was higher for females than that for males – likely as a result of females moving into the suburban neighborhood for egg-laying in open lawns and flower beds. Thus, our data suggests that overall, adult box turtles can survive in suburban neighborhoods at comparable rates to populations in natural habitats. However these neighborhoods may be acting as “ecological traps” selectively reducing the survival of females coming into these areas to nest. Interestingly enough, deaths of telemetered turtles were not dominated by collisions with motor vehicles, which only caused two of the ten deaths observed. There was a suggestion from direct behavioral observations and inferred movement patterns, that some “experienced” turtles had developed strategies for minimizing collisions with vehicles when crossing neighborhood streets. Other causes of human-induced mortality included being run-over by powered lawn mowers, being burned-up in yard litter and drowning in backyard fish ponds. Long-term movement studies showed that (1) eleven years of continuous radio tracking is not long enough to be able to adequately assess or predict the lifelong habitat needs and movement patterns of an individual box turtle, and (2) throughout their lives, many of these turtles showed never before-reported (for this species) annual movements to and from specific winter dormancy areas which may or may not be located within their active season ranges. An uncanny homing ability was often shown, returning to specific dormancy areas which were used year after year. Dates of dormancy entrance and emergence have now been recorded for over a decade or more for individual turtles, together with concomitant temperature data collected from both inside and outside of the dormancy sites chosen. A proposal to establish a network of investigators collecting similar data across extended periods of time for turtles from northern to southern parts of the species’ range, could address interesting and important aspects of the box turtle’s reaction/adaptation to global warming and climate change.
Added by: Admin |