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INFO/LITERATUUR/BOEKEN/ARTIKELS => TURTLENEWS => Topic gestart door: schildpaddennetcrew op 4 Augustus 2008, 08:16:44



Titel: Spring brings turtles out of hibernation
Bericht door: schildpaddennetcrew op 4 Augustus 2008, 08:16:44
 Spring brings turtles out of hibernation   

STRAIGHT GOODS (Golden Lake, Ontario) 22 March 06 The voice of the turtle - Spring brings turtles out of hibernation, to lay eggs above the waterline. (Ole Hendrickson)
One Saturday last spring my partner and I were sitting under the cedars at the cottage, looking out over the Ottawa River. She spotted an odd-looking head protruding from the water, moving steadily past our rocky beach. "I think it's a turtle," she said.
At the start of a trip into town the next day we saw a female snapping turtle laying eggs in a sandy area alongside the cottage road, maybe 50 meters from the water. On Monday I was working alone at the cottage and I saw her again. She was stuck on our deck at the top of the steps leading down to the beach, unable to move forward or retreat.
Messing around with snapping turtles is generally not recommended. According to the website of the Kawartha Lakes Turtle Watch, they can rise up on their legs, rock back and forth, hiss with their mouths wide open, and lunge forward and snap with their powerful jaws.
However, this particular female seemed pretty harmless after her egg-laying expedition. I picked her up, carried her to the base of the steps, and watched her slow progress back to the river. Later that year I found a young turtle following in its mother's footsteps.
Winter survival is even more remarkable than turtle reproduction. Imagine spending months submerged in a frozen lake, half buried in the mud. Like frogs, turtles can get oxygen directly from the water. Unlike frogs, most of the turtle's body is covered by its hard, impermeable shell. Turtles breathe underwater through special patches, with lots of blood vessels, on their throats and near the base of their tails. They also slow their heart rate down to around one beat every ten minutes. A turtle's sleep is far deeper than any mammal's.
On rare occasions turtles wake up and swim under the ice in winter. Painted turtles sometimes emerge from hibernation before all the ice is gone in spring.
For a male turtle, hibernation isn't just about coping with long, cold winters. If it is prevented from hibernating — for example, kept indoors as a pet — it loses its ability to father offspring. Removing a turtle from the wild is a cruel act.
Although snapping and painted turtles are common here, the Ottawa River watershed is noteworthy for its large number of nationally-listed turtle species at risk. The spotted turtle is nationally endangered. Blanding's, spiny softshell, stinkpot, northern map, and wood turtles are also all at risk of extinction and have significant populations in the watershed.
The main threat to turtles is habitat loss. If you have waterfront property, maintaining or restoring natural shoreline vegetation is an excellent way to provide habitat for feeding and basking, and access to egg-laying areas. Other harmful habitat changes include development of upland nesting sites (sandy areas near water), use of herbicides, wetland drainage, river channelization and water impoundment.
All turtles lay eggs on the land, and some species (eg, wood turtles and spotted turtles) spend considerable amounts of time in moist forests. This, unfortunately, makes them vulnerable to illegal collecting for the pet trade, contributing to their decline.
Road kill is a significant cause of death for many turtle species. Adult females, which are particularly important for turtle survival, often choose roadsides for nesting. Here they can fall victim to vehicle traffic. Canada's leading turtle expert, Dr. Ron Brooks of the University of Guelph, warns that even 1-2 percent additional adult mortality from road kill can hasten extinction. Where local naturalists' clubs have put up turtle crossing signs, please drive with caution, especially in spring.
Aboriginal peoples recognize turtles as one of our most remarkable cousins. For many, turtles symbolize the world itself and are worthy of great respect and care.
Dr Ole Hendrickson is an ecologist and a founding member of the Ottawa River Institute, a non-profit, charitable organization based in Pembroke ON Canada. The ORI is aimed at fostering sustainable communities and ecological integrity in the Ottawa Valley and Ottawa River Watershed. For more information please visit the ORI website.
http://www.straightgoods.ca/ViewFeature6.cfm?REF=182