Wednesday, September 11, 2013

Mid-Atlantic Turtle & Tortoise Society Exposes Costs of Building M-83

Letter to Md-Nat'l Capital Park and Planning Commission:

Dear Chairwoman and Commissioners,

As a member scientist of the Box Turtle Advisory Group (BTAG) for the Maryland State Highway Administration during the development of the ICC (Intercounty Connector), I have expert knowledge of the potential damaging effects of a highway construction project, such as the proposed Mid-county Highway Extended (M-83), on wild box turtle populations.

More than 950 box turtles were removed from the footpath of the ICC. That number not only reflects the large area covered by the project and the quality of much of the habitat, but the large number of man hours that went into looking for the turtles, the extensive use of tracking dogs, and the number of field seasons over which the searches went on.  The 950 box turtles removed were a small portion of the total number which could have been rescued if more time and financial resources were allocated to the project during mitigation.  

Construction for ICC coordinated with box turtle removal
photo taken by author
Please consider first that the Maryland Department of Natural Resources lists the Eastern Box turtle as a "Species of Greatest Conservation Need" since its numbers are in decline. Any loss of habitat poses a particular risk to this species given its life style and very low reproductive rate. Adult box turtles live in established, overlapping "home ranges" (averaging less than three to more than twelve acres) where they live their entire life. They do not migrate to new areas if their home land is disturbed but rather remain in place. They will therefore be inadvertently destroyed during roadway clearing operations.

Transfer of turtles from the right-of-way prior to clearing for a roadway can be problematic. Box turtles are secretive, well camouflaged, and difficult to find. Also, adults (which are the only age group likely to be found in significant numbers without the use of trained tracking doges) rarely adjust well to new surroundings and often fail to thrive. There also is the possibility of disease transmission between relocated and resident turtles at the new site. 
Dr. Susan Hagood and her tracking dog Drew looking for
box turtles for removal prior to ICC construction.
photo taken by author

Building M-83 would reduce and fragment box turtle habitat (which currently is plentiful) with potential major negative consequences for the remaining box turtle population:

  • Turtles would be cut off from critical food and water resources, nesting sites, established overwintering sites, and potential mates.
  • The creation of more forest edge would increase access to box turtles by predators (especially dogs and raccoons). Also, predators are more likely to destroy turtle nests at or near the habitat edges than in the center of the forest.
  • Smaller and more slender forest patches (such as M-83 would create) would be subject to more extreme high and low temperatures as well as greater fluctuations in humidity than would larger contiguous forest.
  • Box Turtle, photo by Colin Barnett
    • Box turtles prefer moderate temperature with continuous high humidity. Eggs and young juveniles are particularly vulnerable to desiccation and temperature extremes. Temperature shifts can also change the sex ratio of the developing eggs with unknown consequences to future breeding success of the population.
  • More forest edge and a change in the temperature profile in the forest would encourage a negative change in the plant community with which box turtles have evolved and use for food and cover.
Removal of just 2% of breeding adults per year (which could occur during the construction, and afterwards due to the reasons mentioned above) could cause the local population to spiral to extinction. It could take decades to be realized since box turtles are long-lived, but with inadequate production and recruitment of new young into the population, the species could eventually fail to exist in much of the remaining parkland around the M-83 corridor.

The Mid-Atlantic Turtle and Tortoise Society (www.matts-turtles.info) is a supporter of the TAME Coalition and opposes building Mid-County Highway Extended (M-83).

Sincerely,

Sandy Barnett
At-Large Director, Mid-Atlantic Turtle & Tortoise Society


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1 comment:

  1. shocking how things like this can be proposed, thank you for your time to care for the box turtle.

    ReplyDelete