ADVERTISEMENT
  About the SA Blog Network













Observations

Observations


Opinion, arguments & analyses from the editors of Scientific American
Observations HomeAboutContact

Genetics and Geographical Mapping Help to Crack Ecological Puzzles for Rare Species

The views expressed are those of the author and are not necessarily those of Scientific American.


Email   PrintPrint



threatened california tiger salamander evolution meeting 2011NORMAN, Okla.—Evolution might not sound like it would be of much use to species whose small numbers have already placed them on the endangered or threatened list. But its lessons are being applied with next-generation genetic sequencing speed to solve some of today’s pressing conservation questions.

Many endangered and threatened species are so rare and elusive that even researchers who have been studying them for decades have to make educated guesses about their whereabouts and population dynamics and, therefore, where to focus conservation efforts. But if those assumptions are wrong, hard-won area protections can be for naught.

Hence, some biologists are enlisting the more precise genetic tools to ascertain where some elusive animals might be lurking.

Brad Shaffer, of the Department of Evolutionary and Ecology at University of California, Davis, has been studying the threatened California tiger salamander (Ambystoma californiense) for some 35 years. "It’s very hard to figure out what they do," he said of the nocturnal, primarily subterranean species Sunday at the Evolution 2011 annual meeting in Norman, Okla.

The animals use temporary pools that form during the spring for breeding.  Shaffer and his colleagues collected genetic data from salamander larvae in 16 of these vernal pools in Monterey County, Calif. With genetic analysis, they could estimate the amount of gene crossing  among the pool populations. Anywhere from about 10 to 20 percent of salamander larvae showed that they had parents from another pond. So how were these salamanders getting from pool A to pool B? 

The prevailing wisdom was that the rare animals preferred grassland territory. But Shaffer and his colleagues realized that they still didn’t really know: "How do they traverse different habitats?" he wondered. Because if conservationists preserve grassland habitat but missed a key part of the salamander’s range, the species might suffer even more losses.

To figure out this puzzle, the group used geographic information system (GIS) data to parse the salamanders’ area. From that and what they know about the animals’ biology and lifestyle, they built a model that explains the most likely dispersal patterns based on the genetic information they had gathered. 

Their findings surprised Shaffer—grasslands didn’t end up being the most popular place for the salamanders. Instead, the chaparral proved to be the best habitat for the species, being about twice as appealing as the grassland. Using historical data and a duplicated study in a different area, Shaffer also showed that his model worked across generations and different populations.

"With increasing availability of molecular resources and GIS data, we anticipate that these methods could be applied to a broad range of study systems, particularly those with cryptic life histories that make direct observation of movement challenging," Shaffer and his colleagues concluded in a paper describing some of the salamander research.

Among other sparse species being given a boost by an evolutionary approach are bighorn sheep, the gyrfalcon and the American crocodile.

Follow more from the proceedings of the Evolution 2011 meeting with the #evol11 tag on Twitter.


Image of California tiger salamander courtesy of Wikimedia Commons/John Cleckler





Rights & Permissions

Add Comment

Add a Comment
You must sign in or register as a ScientificAmerican.com member to submit a comment.

More from Scientific American

Scientific American Dinosaurs

Get Total Access to our Digital Anthology

1,200 Articles

Order Now - Just $39! >

X

Email this Article

X