Study to determine if wildlife bridges, tunnels effective

TUCSON, AZ (Tucson News Now) - Several groups will combine forces and funds for a study that will determine whether the wildlife bridges and tunnels in the Sonoran Desert work.

It will be a three-year, $400,000 study with the costs shared by the Arizona Game and Fish Department, the Regional Transportation Authority and the Sky Island Alliance.

The RTA has already spent and or committed $23 million for bridges and overpasses from voter-approved funds of $45 million in 2006.

"We've done this based on sound science," said Jim DeGrood the transportation director for the RTA. "But people are going to continue to have questions about the validity of those expenditures."

The Department of Transportation is spending an estimated $11 million for an animal overpass on State Route 77 near Catalina.

It will connect the wildlife corridor from the Catalinas to the Tortolitas.

The study will determine its value to animals and humans, although putting a dollar value is difficult.

"If we don't monitor the connectivity across those roadways, the species are doomed to decline, become extirpated and leave the area completely," said Scott Sprague of the AZGFD.

There are other bridges built in northern Arizona for bighorn sheep, elk and deer.

The wildlife service has video to prove those animals use the bridges to traverse the roadways.

This is a first for the Sonoran Desert, however.

The species are different and it isn't known whether javelina, mountain lions or other species will follow the same pattern.

There has been some reason for optimism.

There are examples of the desert tortoise, which is endangered, using the underpasses even before they are complete.

"There's a lot of concern about how much money is spent on these things and they're not small investments," Sprague said.

It goes above the value to animals, he added.

"We've seen a tremendous reduction in vehicle collisions in places where they have gone in," Sprague said.

He said studies show a reduction from 80 percent to 97 percent in those areas.

For the RTA, it has another $22 million to spend, but before it does, it believes voters want some accountability.

"We have to be able to demonstrate, prove and show, up or down, that this investment is working or not before we go forward with additional ones," DeGrood said.

Copyright 2015 Tucson News Now. All rights reserved.