Literaturdatenbank
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Hartwig, T. (2004). Habitat selection of blanding’s turtle (emydoidea blandingii): a range-wide review and microhabitat study. Unpublished thesis MS, Bard College, Annandale-on-Hudson, New York.
Added by: Admin (22 Oct 2010 20:35:06 UTC) |
| Resource type: Thesis/Dissertation BibTeX citation key: Hartwig2004 View all bibliographic details  |
Categories: General Keywords: Fortpflanzung = reproduction, Habitat = habitat, Nordamerika = North America, Schildkröten = turtles + tortoises Creators: Hartwig Publisher: Bard College (Annandale-on-Hudson, New York) |
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| Abstract |
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Emydoidea blandingi The Blanding’s turtle is rare throughout most of its range. Habitat loss is considered a key factor in population declines. To conserve a species, habitat selection at all levels of scale must be considered. Much is known about Blanding’s turtle habitat at the landscape scale; however, little is known about range-wide or microhabitat requirements. Therefore, this study consisted of an extensive literature review to determine range-wide habitat characteristics and a field study to determine microhabitat characteristics at a site in Dutchess County, New York. I conducted a literature review of Blanding’s turtle habitat throughout its range to determine similarities and differences in habitats at the range-wide, landscape, and microhabitat scales. Throughout their range, Blanding’s turtles select wetland complexes with shallow (< 2.5 m) water depths, organic substrates, areas of open water, and abundant vegetation. Wetland complexes consist of deeper wetlands for overwintering or drought refuge and a variety of shallow wetlands for feeding and thermoregulation. In the Great Lakes region Blanding’s turtles tend to use ponds with abundant vegetation or herbaceous wetlands while in the Northeast turtles often use shrub swamps. Nova Scotia turtles use bays and floodplain wetlands with a mix of herbaceous and shrubby vegetation. Juvenile turtles tend to use shallower areas than adult turtles - either in the same wetlands that adults use or different wetlands. Water quality and seasonal movements vary by site, although long distances (> 1000 m) are traveled for nesting and other reasons range-wide. Because Blanding’s turtles are very mobile and use a variety of wetlands during an individual’s lifetime, they are susceptible to loss of individual wetlands and landscape connectivity. Management recommendations include conservation of wetlands in groups, 1 km buffer zones around a Blanding’s turtle wetland complex, and corridors between complexes or known habitats beyond the 1 km zone. I studied Blanding’s turtle microhabitat in wetlands constructed for the turtles and reference (pre-existing) wetlands to assess Blanding’s turtle microhabitat selection and the suitability of the constructed wetlands as habitat for the turtles. Microhabitat was determined by radio-tracking individuals to their exact location and recording habitat variables. Blanding’s turtles selected shallow water depths (‾x = 30 cm), muck substrates, and areas of abundant vegetation (total cover‾x = 87%). Buttonbush (Cephalanthus occidentalis) was most important, with mean cover 29%. In the constructed wetlands, Blanding’s turtles selected significantly less cover and warmer water than they did in the reference wetlands. Blanding’s turtles appeared to be using the constructed wetlands to bask and forage in the spring and early summer, but they moved to deeper wetlands in late summer, when the constructed wetlands dried up or became too warm. The turtles also overwintered in the reference wetlands. Habitat constructed for Blanding’s turtles should contain abundant emergent vegetation (including buttonbush in Dutchess County and other areas where the turtles are known to use buttonbush swamps), muck substrates, deep pools and shallow water areas, floating plant material, and submerged aquatic vegetation. Because the constructed wetlands do not provide core habitat for the turtles, destruction or damage to essential habitat for Blanding’s turtles should be avoided. Construction of new habitat near essential habitat should, however, be considered, particularly where habitat has already been fragmented or destroyed. Many other wetland animals use multiple wetlands to fulfill their life history requirements and similar management considerations may apply
Added by: Admin |