Literaturdatenbank
Literaturdatenbank |
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Butler, J. (2002). Population ecology, horne range, and seasonal movernents of the carolina diarnondback terrapin, malaclemys terrapin centrata, in northeastern florida.
Added by: Sarina Wunderlich (28 Aug 2011 21:15:03 UTC) |
| Resource type: Report/Documentation BibTeX citation key: Butler2002 View all bibliographic details  |
Categories: General Keywords: Emydidae, Fortpflanzung = reproduction, Fressfeinde = predators, Habitat = habitat, Malaclemys, Malaclemys terrapin, Nordamerika = North America, Schildkröten = turtles + tortoises Creators: Butler, Commission, Fish |
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| Abstract |
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Malaclemys terrapin centrata Abstract: From May 1997 through March 1998 and from March 2000 tbrough April 2001 my colleagues and I studied diamondbaek terrapins (Malaclemysterrapin) in Duval and Nassau counties. We employed several capture methods, followed their movements with radio telemetry, and studied nesting and nest predation. We captured 173 previously unmarked females. 19 males. 2 juveniles. and 48 hatchlings. We also recaptured 52 females and 5 male. Combining measurements of these terrapins with others previously captured in the same ares, medium plastron length for females was 162.2 mm,. for males 102.5 mm, and for hatchlings 29,9 mrn. Sex ratio was 1.33 males: 1 female, and the population of females using the nesting beach is estimated to be 1.350,8. The most suceessful capture method was hand-capture at the nesting beach; however, we caught only females this way. Modified crab pots allowed capture of both sexes but produced fewer captives and was labor intensive. Cast netting was successful when terrapins were found in groups and were frequently surfacing. We equipped several females from both Deep Creek and the nesting beach with radio transmitters, monitored their activilies, and established that the two sites represented separate populations. In at least 1 year, nesting beach terrapins spent the rest of the year in marshes and creeks 3-5 km upstream in the Nassau River. Deep Creek terrapins were downstream, near the Intracoastal Walerway, in April. May, and June. The rest of the year they were further upstream, and at least 1 wintered in Ihe adjoining Garden Creek. Calculaling the 95% isopleth, the mean female home range was 54.33 ha using the minimum convex polygon (MCP) method, 52,62 ha using the adaptive kernel (AK) method, and 236.92 ha using the fixed kernel (FK) method. For the 50% isopleth the values are 14.91 ha (MCP), 7.69 ha (AK), and 15.Q2 ha (FK). We used head counts (heads/minute) as a measure of lerrapin activity in Deep Creek. No lerrapins surfaced from December through February when water lemperatures (T w) were 19°C or less. When Tw was warmer highesl head counts were recorded when salinity was moderale (15-25 ppt), More heads were also recorded al higher TW and at lower lides. We recorded nesting from late April through late July. We found most newly deposited nesls in May; however, crawl counts indicaled that more lerrapins visited the beach in June. Most depredated nests were found in June or July, and those from July included both newly deposired and recently hatched nests. Nests preyed upon in August and September were all recently halched. Most nests were depredaled within 24 hours of oviposilion. The major nest predalor was the raccoon (Procyon lotor), but we also noted crows (Corvus ossifragus and C branchyrhynchos), boal-tailed grackles (Quiscalus major), an armadillo (Dasypus novemcinctus), and ghost erabs (Ocypode quadrata). Hatching and emergence began in early July and continued into October. The mean emergence period for 54 nests was 68.9 days. In 1997, 21.9% of marked nests were washed out by high tides or storms, and in 2000, 8,9% suffered that fale.
Added by: Sarina Wunderlich |