Literaturdatenbank
Literaturdatenbank |
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Kydd, P. M. (2010). Movement rates, movement patterns, and home ranges of endangered blanding’s turtles (emydoidea blandingii) in nova scotia. Unpublished thesis , Acadia University.
Added by: Sarina Wunderlich (18 Nov 2012 17:43:39 UTC) |
| Resource type: Thesis/Dissertation BibTeX citation key: Kydd2010 View all bibliographic details  |
Categories: General Keywords: Emydidae, Emydoidea, Emydoidea blandingii, Habitat = habitat, Nordamerika = North America, Schildkröten = turtles + tortoises Creators: Kydd Publisher: Acadia University |
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| Abstract |
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Emydoidea blandingii SUMMARY OF KEY RESULTS GPS Technology GPS loggers were effective in tracking Blanding’s turtle. During the initial field trials in 2007, the nesting routes of several females were documented, demonstrating GPS loggers could be valuable in filling knowledge gaps in our understanding of the Nova Scotia population of Blanding’s turtle. In 2008, 1546 point locations were acquired by these GPS loggers deployed on 10 individual turtles averaging 3.6 point locations per day. The number of GPS-acquired point locations peaked in April, during the nesting season, and gradually decreased until October. Of the 2311 acquired point locations from 2007 and 2008, 113 were removed from the initial dataset based on several criteria (see Chapter 2). The most common reason for removal (75 of 113) was a fix quality of 0, which indicates a point location is invalid. On average, 38.9 seconds elapsed from the time the GPS logger was activated to when each point location was acquired. Also, 3.8 attempted point location acquisitions failed between each successful attempt. Home Ranges There was substantial variability between the means of the four home range estimation methods ranging from 12.44 to 707.14 ha. It is probable that the drawbacks of each method contribute to the variation among methods. The MCP and FKA methods tend to overestimate home range size because the methods include areas not necessarily used by the animal (Worton, 1987; Litzgus and Mousseau, 2004; Row and Blouin-Demers, 2006). The NNCH method should be used cautiously in comparisons because the number of neighbours must be chosen by the user, therefore eliminating consistency among studies (Getz and Wilmers, 2004). However, this method shows potential for use when making recovery strategies, as it is the only method that allows the inclusion of information known about the animal. Female home ranges, either with or without nesting movements, were larger than those of males. Although this has only been documented in one other population of Blanding’s turtles (Piepgras and Lang, 2000), it is common among other North American freshwater turtle species, including spotted (Litzgus and Mousseau, 2004), snapping (Pettit et al., 1995), map (Jones, 1996), and Eastern spiny softshell (Galois et al., 2002) turtles. Female home range sizes found in this study are also larger than those found in populations elsewhere in the species range (Rowe, 1987; Ross and Anderson, 1990; Rowe and Moll, 1991; Joyal, 1996; Hamernick, 2000; Piepgras and Lang, 2000; McNeil, 2002; Grgurovic and Sievert, 2005; and Innes et al., 2008). Male home range sizes in this study were comparable to those found in other populations, with some being larger (Piepgras and Lang, 2000; and Hamernick, 2000; Grgurovic and Sievert, 2005) and other smaller (Rowe, 1987; Ross and Anderson, 1990; Rowe and Moll, 1991; Joyal, 1996; Hamernick, 2000; McNeil, 2002; and Innes et al., 2008). The larger Blanding’s turtle home ranges found in Nova Scotia could be attributed to the latitude at which this population is found, at the northern extent of its range. This tendency for populations to have larger home ranges with increasing latitude has been documented in many species in North America including the wood turtle (Arvisais et al., 2002; Smith, 2000). Movement Movement rates were significantly affected by the site and sex of the turtle, with mean movement rates of individual turtles ranging from 208 to 448 m/day. Males moved on average 177 m/day while females moved on average 348 m/day; however movement rates of female turtles include large, often very rapid, movements during the nesting season (Hartwig, 2004). The highest average movement rates occur between 04:00 and 08:00, while the lowest rates occur between 20:00 and 04:00, which is consistent with Graham (1979). Males had higher movement rates than females between 04:00 and 08:00, while their movement rates were lower than those of females during the remainder of the day. Movement rates varied considerably during the six months turtle movements were documented. The highest movement rates for females were documented in June and July, during the nesting season, while the highest movement rates for males, although substantially lower than those of females, were also documented in late June and late July. Temperature, time of day, and time of year had a significant associations with female movement rates, while movement rates of males were significantly associated with only temperature and time of day. Temperature and mean daily temperature were positively associated with movement rates of female turtles, while the associations with total daily precipitation were negative. When testing movement rates of male turtles only mean daily temperature had a significant association.
Added by: Sarina Wunderlich |