(CN) - Two rainwater collectors in an Arizona desert refuge built to help an ailing bighorn sheep population may have to be dismantled, the 9th Circuit ruled Tuesday.
The federal appeals panel in San Francisco revived a lawsuit brought by several environmental groups against the United States Fish and Wildlife Service, which in 2007 built the Yaqui and McPherson water structures in the Kofa National Wildlife Refuge and Wilderness, a 600,000-acre desert refuge.
Wilderness Watch, the Arizona Wilderness Coalition and three other groups say the 13,000-gallon tanks violate the federal Wilderness Act, which prohibits, with a few exceptions, the building of structures in a designated wilderness area. The groups claimed in a lawsuit filed just after the collectors were built that the agency had failed to meet the requirements for an exception.
Congress designated most of the Kofa Wildlife Refuge as a wilderness area in 1990, while only 18 percent of the land is a wildlife refuge subject to the "arguably less restrictive" federal Wildlife Act, the ruling states.
The area is in a sparsely populated, isolated and extremely rugged corner of the Sonoran Desert in southwestern Arizona, and it has been a recognized haven for bighorn sheep since at least 1939.
The sheep population in the area remained fairly stable at around 700 sheep since the early 1990s, but there was a marked decline in the estimated population in 2003. Three years later, a survey estimated that there were only about 390 sheep in the area - a population loss of 30 percent to 50 percent in about 20 years.
Fish and Wildlife found that the water scarcity, mountain-lion predation, translocation, hunting and disturbances by hikers could have all contributed to the population drop.
Ultimately, it decided to build the two water catchments to more evenly distribute the scant 7 inches of rainfall that falls in the area annually, and to avoid moving Kofa sheep to other areas.
U.S. District Judge Mary Murguia granted summary judgment to the agency over the environmental groups, finding no violation of the Wilderness Act in the construction of the water systems.
The three-judge appeals panel reversed Murguia's decision on Tuesday, ruling 2-1 that the service had failed to detail in its report about the population drop that it had met the minimum requirements to build a structure in a wilderness area.
"The report identified many different actions that were likely to lead to an increase in the population of bighorn sheep: reduction in mountain-lion predation, cessation of translocations, moratorium on hunting, and temporary trail closures," Judge Susan Graber wrote for the panel. "Importantly, in contrast to the creation of new structures within the wilderness, the Wilderness Act does not prohibit any of those actions. The service could have taken any or all of those actions without the need for a finding of necessity. Yet nowhere in the record does the service explain why those actions, alone or in combination, are insufficient to restore the population of bighorn sheep."
Graber added that the agency had not answered the vital question of whether the catchments are actually needed, and that its own documentation indicates other strategies could have been as effective as rainwater-collection tanks.
"In light of the many other potential avenues of achieving bighorn sheep conservation identified by the service itself, the service must provide enough evidence and explanation in the record to assure this court that it fully considered those avenues and nevertheless rationally concluded that new water structures are, in fact, necessary," Graber wrote.
Calling the service's record "wholly inadequate to meet that requirement," the panel ruled to reverse and remanded, and directed the Arizona federal court to determine whether to dismantle the structures, have Fish and Wildlife prove "necessity" under the Wilderness Act, or come to another arrangement.
Judge Jay Bybee dissented from the court's finding.
"The majority wants the service to hold us by the hand and to slowly and exhaustively explain to us its actions at every junction along the way," he wrote. "But the service's reasoning and conclusions are readily discernable from the record, and so we are required to uphold the service's decision to redevelop the two water tanks."
Though Bybee's colleagues found Fish and Wildlife's evidence inadequate, Bybee argued that the agency properly addressed the question of necessity.
"The record in this case clearly indicates the agency conducted a comprehensive analysis of the possible causes for the bighorn's decline and reasonably decided to address the most pressing cause," Bybee wrote.