Showing posts with label Nerodia sipedon insularum. Show all posts
Showing posts with label Nerodia sipedon insularum. Show all posts

Tuesday, March 20, 2012

Student Project on Lake Erie Water Snakes

Lake Erie Water Snakes, Nerodia sipiedon insularum
University of Cincinnati' s Lauren Flick, a 19-year-old, triple-major senior, will present findings at an upcoming regional conference on the first-ever use of a surgically implanted device to record the habits of snakes in their natural environment. This particular study holds promise in “keeping score” as Ohio’s Lake Erie water snake defends its native habitat against an invasive fish species.

Thanks to research by a University of Cincinnati undergraduate student and two team members, there’s a new tool that’s now been tested and found to work in continuously recording the habits of snakes.

This small-scale study is the first-ever use of Lotek Archival Tags (LATs) on snakes, since the LAT devices were originally developed for use in avian and fish species due to LATs’ ability to measure temperature and pressure – measuring pressure translates into altitude and depth.

UC’s Lauren Flick, a triple-major pursuing simultaneous undergraduate degrees in biology, psychology and criminal justice, will present the findings of the snapshot study, “Comparing the Effectiveness of Lotek Archival Tags (LATs) in a Behavioral Study of the Lake Erie Water Snake,” at the March 23-25 Midwest Ecology and Evolution Conference, a conference specifically for undergraduate and graduate student research that will draw representatives from regional schools.

Participating in the study with Flick were lead researcher Kristen Stanford, a doctoral student at Northern Illinois University and recovery plan coordinator for the Lake Erie water snake, and Lindsey Korfel, a student at Wittenberg University. Their research study was conducted during summer 2011 at Ohio State University’s Stone Laboratory located on Lake Erie.

The traditional manner for tracking snakes’ movements is primarily with a radio transmitter. In other words, a researcher would attach a location transmitter to a ground snake and then hope he or she could then stay or get within range over a period of time to visually determine its habits

What Flick, Stanford and Korfel did was to catch two female Lake Erie water snakes (LEWS) and arrange for the implantation of LATs. Importantly, the LATs record and store data on the snakes over time, such that it’s not necessary for a researcher to be within visual range of the snake. In fact, a researcher could leave the snake undisturbed in its natural habits and environment for days, even weeks, at a time when using a LAT. (During this study, the snakes were not harmed, and the LATs were removed at the end of the study.)

“This was proof of concept that use of LATs in reptiles is a viable research method,” said Flick, a resident of Cincinnati’s Green Hills community. “For a study like ours, it’s harder and less effective to rely solely on using the traditional radio transmitter on a water snake moving in the depths of the Great Lakes. And even when using the average transmitter with a ground snake, you have to stay within about 50 meters for the tracking technology to work. That kind of close tracking could also serve to disturb the very habits a researcher is hoping to observe.”

The Lake Erie Water Snake (LEWS), found only in the western Lake Erie waters of Ohio and Canada and only recently removed from the list of federally endangered and threatened species, is estimated to number more than 8,000 adults. Its population size had fallen to about 1,500 adults in the mid-1990s – very low because they were often killed by humans and because of loss or degradation of habitat on the shoreline or on the Lake Erie islands where they are native.

Explained Flick, “Basically, the islands and shorelines are an important part of the snakes’ habitat. They live on land and only forage in the water. Humans on the Lake Erie islands didn’t, for a long time, see value in having snakes around, even though we now know that these nonpoisonous snakes were and are a valuable part of the ecosystem.”

And while those numbers have recovered sufficiently to remove the species from the endangered status, it’s important to understand how the species is faring in terms of foraging, maintaining body temperature and finding appropriate mating, resting and hibernating environments because the LEWS are a major player in combating the invasive round gobi fish.

The round gobies, a bottom-dwelling species, are considered very harmful because they are voracious nest predators of many of Lake Erie’s native game fish and bottom-dwelling fish, and there are now estimated to be billions of the round gobies in Lake Erie. However, as it turns out, the native Lake Erie water snakes will eat round gobies.

And even though the student research was a snapshot involving just a pair of snakes, they found some intriguing results recorded by the LAT devices.

Said Flick, “Previous studies have estimated that the LEWS spend only 7 percent of the time foraging for food. The snakes that we studied actually spent 20-25 percent of the time foraging. One of the snakes even went out foraging at about midnight, which is unusual because the LEWS are not normally nocturnal.”

And since it’s estimated that 90 percent of the LEWS’ diet consists of round gobi fish, more time eating by the LEWS should translate into fewer round gobies.

The story is reprinted from an original story written by M. B. Reily and materials provided by University of Cincinnati.

Monday, August 15, 2011

Lake Erie Water Snake Removed from Endangered List

Nerodia sipedon insularum. Photo Credit 
Kristin Stanford
By Sabrina Eaton, The Plain Dealer 

WASHINGTON, D.C. - A non-poisonous gray snake that lives exclusively on Lake Erie's limestone islands has grown sufficiently in population to be removed from the nation's endangered species list.

Conservationists attribute the Lake Erie watersnake's dramatic recovery to a decade long public relations campaign and swelling numbers of an invasive fish from Eurasia - the round goby - which the snakes love to eat.

On Monday, Interior Secretary Ken Salazar announced the snake has joined the bald eagle, peregrine falcon and the American alligator in no longer being endangered. It is the 23rd endangered species to be delisted due to recovery.

"Our lake faces many challenges, but the recovery of the Lake Erie watersnake is living proof of what we can accomplish by working together," said Toledo Democratic Rep. Marcy Kaptur.

Ohio State University snake specialist Kristin Stanford, who leads a yearly drive to count Lake Erie watersnakes, says there are now between 12,000 and 15,000 of them, a tenfold increase since they made the list in 1999.

Although the 1 1/2- to 3 1/2-foot-long snakes are being removed from the federal list, they will continue to be protected in Ohio. Purposely killing one could still result in a fine of up to $1,000, says Stanford. Population levels will be monitored for at least five more years to ensure the species remains stable.

“As with most conservation success stories, the comeback of the Lake Erie watersnake is the result of different groups of people working toward a common goal," said U.S. Fish and Wildlife Service Director Dan Ashe.

Stanford, who calls herself the "Island Snake Lady" and whose snake counting work has been featured on the Discovery Channel show "Dirty Jobs," says the snakes were so ubiquitous when European explorers first arrived in Ohio that the Lake Erie Islands were initially named "Islands of Serpents."

Their numbers declined between the 1950s and 1980s, as the islands became a popular vacation destination and settlers destroyed their habitat and killed them in the mistaken belief they were venomous.

"If you pick them up and try to mess with them, they bite and poop and squirm and do what's necessary to make sure you leave them alone," says Stanford. "They prefer to be left alone."

According to the U.S. Fish and Wildlife Service, Lake Erie watersnakes are closely related to northern watersnakes, but lack the other species' prominent bands. The all-gray snakes were better able to survive by camouflaging themselves on the islands' limestone, helping them to avoid consumption by birds, foxes and raccoons.

Stanford and others began an informational campaign to publicize the snakes' history in the region, and the fact that no snakes around Lake Erie are poisonous. She said Ohio's only poisonous snakes - copperheads, massasauga rattlesnakes and timber rattlesnakes - live farther south.

The arrival of round gobies in Lake Erie - a bottom dwelling fish that came from the Black and Caspian seas via ballast water from ships - crowded out native fish like madtom, stonecat, and longperch, but helped Lake Erie watersnakes rebound.

More than 90 percent of their diet is round gobies, and the snakes' size, and reproductive rates have exploded since the invasive species arrived, says Stanford.

"You hear a lot of negative things about invasive species, but a lot of times you don't hear about the positive impact," says Stanford. "With the watersnake, it was a positive impact."