Terrestrial desert tortoises in Sonora, California and Mexican Sinaloa were one of a century ago among the very abundant species. In the Mojave Desert we would have counted up to 150 copies per square kilometer, in Southern California to five hundred. The evolutionary bet for a stay in an extremely hostile environment has paid off. In the wilderness, only the minimal predators were pursued, and with regular climatic fluctuations they simply cope with the fact that they were sleeping underground. There, in fact, they spend 95% of their lives, so people are almost not registered. And despite the fact that once the total area of their area could count on 7,500 square kilometers.
One shot after another
With adaptation to the overflowing environment and long-term stay under the ground, the desert turtles combine two distinctive features: longevity and somewhat poor tendency to reproduction. Individuals of Gopherus agassizi live for up to eighty years and do not need to hurry up somewhere. Still, he got "fate". The first blow for numerous populations was chronic upper respiratory tract infection (URTD), which was noted by biologists in the 1970s. After that, she suffered an epidemic of cutaneous dyskeratosis that decimated their populations. The "lazy" turtles have not been able to reverse the counts. He became a species listed in the Red List among the Vulnerable.
And then people enter the turtle story. The unhappy desert of the American continent, which still guaranteed turtles, was of great interest. In the field of source turtle populations, several military spaces and shooting ranges are gradually being expanded and gradually expanded. Fortunately, the presence of artillery from the Fort Irwin mariners did not benefit from the tortoises, and even worse they were led around Ivanpah, where a very ambitious solar project was born. The largest enemy of desert turtles remains the wind and solar farms to this day, because the construction of sustainable resources is very unsustainably disturbing their territory.
When people "rescue" the turtles
For the first time in 2008, the army, and in 2011, representatives of renewable energy sources will understand the "power of positive advertising" and will invest considerable resources in the relocation of endangered turtle populations outside the ranges of shooting ranges and solar farms. Ivanpah Solar Electric, for example, pays $ 22 million to biologists who move the turtles 35 kilometers further. No less spectacular was the action of naval infantry, in which the collected turtles were moved (with massive attention of the media) with helicopters. People who have devastated the desert turtle environment have shown themselves in better light. They helped save them.
But the story with a good end somehow did not show up. The explanation is Rob Fleischer, an evolutionary genetics expert at the Smithsonian Institute in Washington, who was invited to evaluate the success of this turtle translocation. Together with his colleagues, he first captured 92 young specimens on sites along the interstate I-15, where the turtles were transferred. Based on collected blood samples and DNA, they identified their turtle parents (who were sampled before the transfer). And he found that only 35 young turtles came from the turtle mothers who were moved here. That would not be so bad yet.
Mates are no longer in power
However, the results showed that, as opposed to the transferred female turtles, none of the transferred males were affected. The females only married males who were in a new location at home. "It was very unexpected," says Fleischer. "Transmitted females can obviously continue to reproduce, but males have no interest in mating after translocation." Ultimately, there is a significant and irreversible loss of genes that is particularly dangerous for populations already at risk of extinction. "We do not come up with all the genes, but their substantial part," adds Fleischer.
What exactly prevents males transferred to mating is not yet clear. Biologists believe it could be a combination of factors: food, water resources, and shelter problems in an unfamiliar environment. "All this is stressing, just like the presence of busy competitors. Trying to cope with a new environment takes them energy that is not enough for mating, " says Kristin Berry, a tortoise expert at the University of Riverside. "The stress associated with relocation can be far more serious for these turtles than we ever thought."
Author: Radomír Dohnal
Source: Ekolist.cz