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Belzer, W. R., & Seibert, S. , Long term movement histories for headstarted juvenile, and translocated adult and juvenile eastern box turtles in nw pennsylvania sanctuaries. 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: Belzer2007a View all bibliographic details  |
Categories: General Keywords: Habitat = habitat, Nordamerika = North America, Schildkröten = turtles + tortoises Creators: Belzer, Seibert Collection: Third Box Turtle Conservation Workshop |
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| Abstract |
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We present hand-drawn overhead transparency, and ArcView-plotted GPS, maps of locations recorded since 1993 for translocated adult, and 2-yr-old headstarted, eastern box turtles in our repatriation studies at two (200 vs 500 acre) sanctuaries in NW Pennsylvania. Archived locations recorded at 1-10 d intervals for each turtle, across consecutive yrs, provide insight into movements overlooked by occasional glimpses at habitat use. Our 20 plus representative maps (from >100 telemetered turtles) illustrate that: translocated adult box turtles, and headstarted juveniles, often move well beyond small (200-500 acres) sanctuary boundaries; most translocated adults don't develop site fidelity within sanctuary boundaries despite repeated food and mate offerings at a central site; repeatedly retrieving dispersing turtles, to return them to a sanctuary's core, probably helps little, if at all, to promote adoption of habitat inside the sanctuary; short term (e.g. 2 yrs) confinement of translocated box turtles does not guarantee their site fidelity for the locale after release; translocated adults, and headstarted juveniles, rarely disperse in directions heading back toward their origins; our first years of field data from 2-yr-old juveniles, headstarted by the Michell protocol, suggest that the male juveniles are more likely to leave a sanctuary; each passing year sees more, who had initially demonstrated apparent site fidelity, begin outbound migrations, leaving a currently unclear, fluid assessment of this strategy's promise; individuals differ greatly in movement pattern and range, and propensity to disperse ~ behavioral generalizations are hard to come by for this species; habitat locales favored by some individuals are ignored by others; 2000 acres of unfragmented habitat is probably a conservative minimum for a sanctuary to be considered as a potential box turtle repatriation site; tens of thousands of turtles could be required to even hope to rebuild density sufficient for a population to become self-sustaining; and, a century or more of sustained effort may be needed to simply discover whether it's possible to ever rebuild a self-sustaining population Our early findings raise questions that won't find answers for many decades. For example: is "transience" (occasionally reported in the behavioral repertoire of wild adults) a genetic or life stage phenomenon? Is there a sexual predilection for becoming a transient? Do transients ever reverse course and eventually revisit populations or habitat they passed through years previously? If rebuilding a self sustaining population ever proves to be possible (not at all clear from our work to-date) could such efforts that use headstarted juveniles succeed in habitats somewhat smaller than what might be required if translocated adults were used? It's almost certain that high resident densities are needed for population sustainability (not to be confused with the sighting of {relic} individuals in ancestral habitats for many decades after their population actually fell below its capacity for self-sustainability). Aggressive proactive protection of any remaining high-density populations is critical and should be a high priority for management agencies. Trying to rebuild such a population may prove to be virtually impossible.
Added by: Admin |