Habitat loss is probably the most sure way to extingish animal species. Without it, turtles are without places to find food, shelter and mates. Food webs that took tens of thousands of years to establish disappear. Once the habitat destroyed, it is very labor intensive and time consuming to repair it. Habitat Loss can be divided into three types: destruction, fragmentation and degradation.

Habitat destruction is the complete alteration of habitat, such as clear cutting and draining of wetlands. Some of the causes of habitat destruction are agriculture, human development, live stock grazing and logging. Classic examples of these are logging of tropical rain forests, turning the great plains into agriculture land, over grazing by sheep & cattle, and damming of a river. Habitat destruction might not all happen at once, but could for example happen in the course of twenty years. Lots of forests and grasslands that once surrounded cities have been claimed by urban sprawl. Lands that once gave children the opportunity for unstructured play are now golf courses and strip malls. One turtle species affected by habitat destruction is the Ornate Box Turtle (Terrapene o. ornata). Biologists believe that destruction of the Great Plains was "the greatest single factor affecting ornate box turtle populations over the past century across most of their range in the West" (Redder, Dodd, Keinath, Mcdonal & Ise 2006).

Habitat fragmentation is less visible and less talked about in the media than habitat destruction, but it also has a profound negtive affect on wildlife. Habitat fragmentation is the act of breaking up a large piece of land into smaller pieces. This causes a decease in the total amount of habitat, isolation of the fragments, restricts species movement and creates more habitat edges. Fragmentation could be caused by building of roads, fences, hiking trails and powerlines.

When larger tracts of habtiat are broken into smaller tracts, the amount of edge habitat increases. These edge areas tend to be less humid, let in more light and contain higher predator density. Three-toed Box turtles are well known for eating mushrooms, so much that it can make their flesh poisonous during peak mushroom season. The reduced humidity around forest edges may hinder mushroom growth. Edges can also be an ecological trap. Road sides make ideal nesting grounds for turtles. In turn, this leads to road mortality in high traffic areas and also exposes the nest to many predators that hunt along the roadside.

Road surfaces are an ideal place to thermoregulate, because they hold heat and provide an exposed area for basking. This also exposes turtles to road mortality and to turtle collectors. Each year, tens of thousands of turtles are killed on roads. Most of them are breeding adults and many of those are females out looking for nesting sites. When the numbers are examined: 80-90% of nests are depredated during the first 24 hour period after being laid, and very few hatching turtles make to adulthood. We reach a statistic of one out of two to three hundred eggs make it to adulthood. The loss of every singe reproductive age turtle hurts the local population. In some isolated populations, there are only 15-20 adult individuals left.

Thankfully, there are ways to reduce turtle and other wildlife mortality on roads. Wildlife crossings can be built over roads and under roads. These crossings come equipped with fences that funnel wildlife to them. Nature photographer Joel Sartore captures one of the the wildlife overpasses in Alberta, Canada in his Fragile Nature gallery. Another type of wildlife passage was made under a North Florida highway that crosses Lake Jackson. This project cost 3.4 million dollars, and is projected to save wildlife and protect motorists from them. Republican Senator Tom Cohurn (of Oklahoma) calls it one of the 100 wasteful items in Obama's federal stimulus package. To Conservation Biologists, this would probably be on the 100 most meaningful items in Obama's presidency.

Aquatic habitat loss or alteration could be divided into lentic (nonmoving water) and lotic (moving water) types. Llentic habitat loss could be draining of a wetland, removing of lentic habitat creaters (such as beavers), acid rain, eutrophication from fertilizer run off, or replacing natural edges with concrete or rocks. Damming and channelization are the two big causes of habitat loss and alteration in lotic environments. The damming of rivers essentially turns a lotic environment to a lentic environment. It also isolates aquatic wildlife populations up river from the ones down river of the dam. Annual water level cycles are also affected. Some turtles such as the River Fly turtle (Carettochelys insculpta) depend on seasonal floods for reproduction. Additional aquatic habitat is lost or changed with channelization. Rivers are made shorter by straightening them, they are made deeper, and sometimes their banks are altered as well. Falling trees and branches are sometimes removed, thus stripping basking spots for turtles. Natural sand banks and bars could be removed, depriving turtles of basking and nesting sites.

Wetlands have disappeared at a horrifying rate since the European settlement of America. From the 1780's to 1980's, some states have lost as much as 91 percent (California, Ohio, Iowa are the leaders) of their wetlands. Overall, of the original 220 million acreas of wetlands, only 100 million are left. The U.S. Environmental Protection Agency (EPA) estimates that the U.S. loses around 100,000 acres of wetlands every year. Each acre of wetlands can hold around 1 to 1.5 million gallons of floodwater. In Wisconsin, over half of the 10 million acres of wetlands have been lost to human development. Turtles such as Blanding's and Bog Turtles are severely affected by alteration of wetlands, such as fragmentation and draining/filling for agriculture and other human development. In North Carolina alone, 95% of Bog Turtle habitat has been lost. Many other species of turtles use wetlands surrounding rivers and lakes as nursery sites for young aquatic turtles. Federal programs such as the Wetlands Reserve Program and the Conservation Reserve Program have created incentives to private land owners to protect wetlands. Both of these programs are packaged into the Food, Conservation, and Energy Act of 2008 (aka 2008 Farm Bill). Wetlands are benefical to everybody. They help filter drinking water and provide flood control. New York City uses around 1.3 billion gallons of water each day, 40% of which is filtered by the Catskill/Delaware Watershed. By using this watershed to filter the water, the city does not have to build a water filtration plant, which would cost an estimated $8 billion dollars with an additonal $400 million in operation costs.

Page 1 2 3

References