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Over the past twenty years or so, invasive species have played an increasing role in the destruction of natural resources. In the United States alone, scientists project that invasive species cause $120 billion dollars in damage every year (Pimentel, Zuniga, Morrison 2004). In addition to affecting our pocketbooks, invasive species have contributed to the decline of 40% of protected animals listed under the Endangered Species Act (Wilcove et al., 1998). So why are invasive species so bad? Well, invasive species are not just animals that are found outside of their natural range. They actually cause harm to native species. Some factors that contribute to the success of invasive species are that they tend to have high reproduction rates, live in a broad range of habitat, live close to humans and have high dispersal rates. The Red-eared Slider is a prime example of this in the turtle world. They tend to mature at faster rates than other pond turtles, they have fairly high clutch sizes, they live in a broad range of habitats and appear to benefit in human modified habitats. Another example is the Red imported Fire Ant (Solenopsis invicta). This species was accidentally introduced to the southern half of the United States (1930s) and many other parts of the world. It has caused declines in ground nesting birds, amphibians and reptiles. The Food & Drug Administration estimates that this ant causes $750 million dollars in agriculture losses per year. The U.S. government spends around $5 billion dollars a year in fire ant control. During nest building and egg laying, fire ants can cause the greatest damage to turtles. They may be attracted to the nest by scent and will swarm to the nest, killing the nesting turtle or hatching baby turtles. All turtles from freshwater to marine species are affected by fire ants. Invasive species are not just animals, but also plants such as Purple Loosestrife (Lythrum salicaria), Common Reed (Phragmites communis), Reed Canary Grass (Phalaris arundinacea) and Japanese Stilt Grass (Microstegium vimineum). All four are responsible for degrading the habitat of the Bog Turtle by choking out native wetland plant species. In New Jersey, biologists are using a prescribed grazing program to help restore bog turtle habitat. Using livestock to control invasive plants eliminates the chance of herbicides doing damage to the ecosystem (Tesauro 2001). In addition to grazing, herbicide control, water level manipulation and mowing up the plants, there are biological controls that use leaf beetles (Genus: Galerucella) and weevils (Genera: Hylobius & Nanopheyes) to combat Purple loosestrife. One might ask: why introduce invasive species to the areas that they are not native to? The answers range from accidental release to controlling agricultural pests. Red-eared Sliders were released all over the world because of the pet trade. Purple Loosestrife was bought here in ship ballast and as a medicinal plant. Reed Canary Grass was actually used to control erosion and also as forage for livestock.
Turtle historians believe that humans have included turtles in their diet throughout the 200,000 year existence of modern humans. There have been documented cases of human consumption of turtles for the last 20,000 years. Turtles have been uses as food, oils, traditional medicine, jewelry, combs, musical instruments, and in regalia. In many countries and cultures, turtle meat is regularly a part of the diet. In the early 1900s, Diamondback terrapins were one of the most sought after dishes. During William Howard Taft’s presidential years, it was commonly served at the White House during state dinners (Brennessel 2006). Luckily for the terrapin, turtle dishes lost their popularity during prohibition and the Great Depression because of sherry as an ingredient, the cost of turtles and the labor intensive prep work that is required (Brennessel 2006). Today, turtle meats are still very popular in many areas around the world. The Common Snapping Turtle, Red-eared Slider and Softshell turtles are the top three of the turtle meat trade. Many, if not most of these turtles are destined to be shipped out to foreign markets, mainly China. From 1996 to 2000, turtle export data shows around 51 million turtles worth 41 million dollars were exported. This consisted of 37 species, with most of them being sliders, painted turtles and river cooters/redbellied turtles (Need & Gibbons 2004). The jury is still out on the sustainablity of using turtles for human consumption. Turtle natural history varies from species to species; some species do very well in human modified environments, while others suffer population decline. Most turtle biologists feel that exploitation of turtles for human consumption is unsustainable.
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