JR. Seminar

Christian Paparazzo

Title: Impacts of human activity and natural global changes on Glyptemys Insculpta (Wood Turtle)

Environmental success is a crucial aspect of keeping species alive. In order to keep the environment healthy and make sure that the environment can succeed abiotic and biotic factors need to be taken into consideration. Abiotic factors are nonliving things that impact an environment. This could be things like climate change and erosion. Biotic factors are the living factors that play into environmental success. Some biotic factors are correlated human impact. Habitat destruction, agricultural impacts, recreation, etc. Abiotic and biotic factors limit a species geographic range. Negative interactions between a population and these factors is hard to control. In order for environmental/species success there has to be a healthy medium between the environment/species and abiotic/biotic factors.

Over the past few decades the environmental landscape has drastically changed. Ecosystem efficiency is dropping. In New England, specifically heavy wooded areas such as New England and Canada have been put under a lot of stress. Most of this stress is impacted by things such as global warming and human activities such as farming, recreation, and habitat destruction. Humans have a direct impact on the environment even though some of these changes seem like a small change to people it creates an even bigger problem for other species. Species have to adjust to survive because human activity is always increasing and more and more resources are being used and taken for granted. Many species feel this direct impact.

Figure 1: The map above is a distribution map of G. Insculpta throughout the United States and Canada

The wood turtle or (Glyptemys Insculpta) one of the many species that are affected by human activity. The population is decreasing. Wood turtles often lay their eggs in heavily dense woody areas with a lot of cover. Between 1996 and 1997 alone there was a drop in  nest success rate. It went from 74% to a 65% (Tuttle, 2005). Wood Turtles are a good species to test because the adults are easily tracked. The wood turtle does not move far from nesting sites. They usually stay with 100 meters of the area. They also have a long lifespan. Another positive to tracking wood turtles is even after they die their shells remain for a longtime. This is good because it can give us a hint as to how they died. Glyptemys Insculpta like to stay near rivers. They feed off of both land and sea species (Walde, 2007).

Human activity such as recreational activity and agricultural practice are main reasons in the declining population of G. Insculpta. Deforestation is indirectly killing G. Insculpta. A change at this scale is devastating not only to G. Insculpta but its prey and predators also. Agriculture is pervasive. Agricultural machines do cause problems to G. Insculpta. Most of the time the wood turtles are killed or injured. Another main reason for the decline in population of G. Insculpta is Highways. When the eggs hatch the turtles are drawn to the lights and sometimes head toward the highway where they’ll more than likely get run over by a car.

A 20 year study ran by Steven Garber and Joanna Burger from 1974-1993 highlights some of the big ideas. In 1974, 133 total Glyptemys Insculpta were marked in 2 different sites (SItes are separated by a man made pond. The turtles were observed a total of 1176 times. When the area was restricted from human access and when there are no changes to the environment, the wood turtle population was stable. When they allowed human recreation the wood turtle population started to decline. Within 10 years all of the 133 wood turtles marked were dead. In about 20 years 100% of the marked population was gone because of human recreation. The abiotic factors such as water quality and warming weather did not really change over the 20 years meaning that the abiotic factors at the time were not very harmful to the wood turtle population. G. Insculpta are an ideal species to look at. They are very easily tracked and can managed (Garber,1995).

Figure 1: The graph shown is from the study explained above. It shows the decline in the wood turtle population in Connecticut over 20 years. After 20 years 100% of the marked turtles were dead.

G. Insculpta is an interesting species to look at. They have very few natural predators so why is it that the population is decreasing?. Agricultural machinery is  very deadly for wood turtles. The machines can directly kill the wood turtles or even dig up nesting sites. Agriculture leads to an increase in adult mortality and a large increase of infant mortality.  Wood turtles are semi aquatic usually spending time in the rivers. Agriculture machinery also affects the rivers with an increase in erosion and more pollutants (Saumure,2006).

Agriculture is a very important aspect of human life. But there are ramifications that people tend to overlook. Over the past 360 years there has been a 94% decrease in temperate forest. That is a huge change that people don’t pay attention to. In a study ran in Quebec, Canada 66 wood turtles in 1995 were tracked, marked, sexed and measured. (22 males, 28 females, 16 juveniles). The G. Insculpta were captured a total of 978 times from 1995-1999. They were tracked using radio-telemetry which is a tracking device implanted into the shells of the wood turtles. The wood turtles were being tracked 1-2 times per week  The site being used is along a 6.3km river with 7 farms scattered around. Of all the wood turtles tracked 20% were killed by direct effects of agriculture. Many more were injured or displaced. During the 1998 and 1999 season there were 2 new landowners. Over this time period the 2 new owners would hay twice each summer. Raking and mowing caused some problems. In 1998-1999 30 wood turtles were recaptured. Of the 30 tracked 6 were killed due to agricultural practices 1 of them even being completely cut in half from the mowers. None of them died from natural causes. About 50% of wood turtle mortality is caused by mechanical habitat destruction. Agricultural practices along rivers and near highways creates an extensive problem (Samure et al, 1998)Figure 2: The figure is showing injuries occurred from agricultural practices. This figure is from the study described above.  

Another problem that wood turtles face is highways. With a constant changing landscape its becoming more dangerous for turtles. Newborn turtles have an attraction to light and tend to veer off and head toward the lights. There are a lot of roads that are being expanded and added to. Movement patterns of wood turtles have changed. More and more wood turtles have been displaced due to road development (Gibbs, 2002).

There are several ways to conserve the wood turtle population. The most popular option is to actually create artificial nests for the G. Insculpta. The nest would be protected from predators and will not be introduced to human activity. By putting wood turtles into protected forest ensures a very high survival rate of infant wood turtles. Another way to conserve wood turtle population is to map wood turtle movement in an area and create little tunnels that are more accessible for the wood turtles to use.

Wood turtles also known as  Glyptemys Insculpta  is native to northern areas including the North East and Canada. They are easily tracked and can be monitored easily as well.  Human activity such as driving, agriculture, and deforestation has caused a decrease in population of the wood turtle. With almost no natural predators the decline in G. Insculpta populations is caused from humans.

References:

Jones, Michael T., “Spatial Ecology, Population Structure, and Conservation of the Wood Turtle, Glyptemys Insculpta, in Central New England” (2009). Open Access Dissertations. 39.   https://scholarworks.umass.edu/open_access_dissertations/39

Kevin J Gaston. “Geographic range limits: achieving synthesis 276 Proceedings of the Royal Society B: Biological Sciences” (2009).

Tuttle, Sheila E., and David M. Carroll. “Movements and Behavior of Hatchling Wood Turtles (Glyptemys Insculpta).” Northeastern Naturalist, vol. 12, no. 3, 2005, pp. 331–348. JSTOR, www.jstor.org/stable/3858690.

Saumure, R.A. et al, Effects of haying and agricultural practices on a declining species: The North American wood turtle, Glyptemys insculpta, Biol. Conserv. (2006), doi:10.1016/j.biocon.2006.11.003

Walde, Andrew D., et al. “Nesting ecology and hatching success of the wood turtle, Glyptemys insculpta, in Quebec.” Herpetological Conservation and Biology 2.1 (2007): 49-60.

Garber, Steven D., and Joanna Burger. “A 20‐yr study documenting the relationship between turtle decline and human recreation.” Ecological Applications 5.4 (1995): 1151-1162.

Gibbs, James P., and W. G. Shriver. “Estimating the Effects of Road Mortality on Turtle Populations.” Conservation Biology, vol. 16, no. 6, 2002, pp. 1647-1652.
Presentation:
https://www.youtube.com/watch?v=ednxD07NS_c&t=7s