Into the Trenches and Off of the Railways

     As the United States expanded to become a nation that is bordered by both the Atlantic and Pacific oceans, railroads were put into place to facilitate the movement of people and necessary materials. While the network of rails became integral to the expansion of the country and a feat of the technology of the time, they are a structure that also carries the threat of death to wildlife, especially turtles and tortoises. These animals are particularly threatened by the dangers of the railroad because they are not only vulnerable to colliding with a train, but they can also become trapped between the rails to meet their unfortunate end. It was this issue of railway tortoise mortality that prompted the researchers to determine why these animals are perishing between the rails and how to help these animals overcome this barrier to their long-term survival.

     In order to tackle the problem presented to them, the researchers chose a location centered around an inactive railway that cut through a coastal habitat in the John F. Kennedy Space Center where tortoise entrapment and mortality was a common occurrence. The first thing that they had to determine was if the railway was acting as a barrier to the movement of the animals, and they did this by electronically tracking the movement of ten tortoises that they found inhabiting the location. Each tortoise was fitted with a transmitter and then tracked for a year to see how often (if ever) they crossed the railway. Ultimately the researchers were able to confidently determine that the railway was a barrier to the movement of the tortoises and move on to the next phase of their study.

     Once the railway was determined to be a barrier to the movement of the tortoises in the study, the researchers set out to determine the how and why of the situation. To answer this question, they captured tortoises that lived both close to and far from the rails to observe in two testing plots. The first plot was a rectangle marked by thin pieces of wood on the ground that acted as a control, and the second was a rectangle of equal size contained within the rails. The researchers watched the tortoises to determine how long it took them to “escape” each plot, and they found that none of the animals successfully escaped the rails despite their best efforts. After this trial, the tortoise volunteers were returned home so the researchers could begin testing their proposed solution to the railway problem.

     Any solution proposed would not only need to be useable by the tortoises but cost effective to be reasonably implemented in the future, so the obvious solution of removing the tracks was not an option. Instead, the researchers dug trenches beneath the tracks at regular intervals then placed wildlife cameras near their entrances to record the use or lack thereof by the tortoises. Within four days, the tortoises began to use the trenches to cross the tracks and access the previously inaccessible portion of the habitat. These trenches not only offer a safe underpass for tortoises, but since they are open on top, they are also an avenue of escape for any animals trapped between the rails.

     While the subjects of this study were all members of the gopher tortoise (Gopherus polyphemus) species, this trench system is not a species-specific solution. Railway caused wildlife mortality is not a problem unique to Florida, and it happens wherever a railroad moves through a habitat containing wildlife. Since the trench solution is relatively inexpensive and showed promise quickly during the testing period, it is possible that these trenches may soon be a common sight wherever railroads are present.  

Reference:

Rhett M. Rautsaw, Scott A. Martin, Bridget A. Vincent, Katelyn Lanctot, M. Rebecca

     Bolt, Richard A. Seigel, and Christopher L. Parkinson (2018) Stopped Dead in Their

Tracks: The Impact of Railways on Gopher Tortoise (Gopherus polyphemus)

Movement and Behavior. Copeia: March 2018, Vol. 106, No. 1, pp. 135-143.