Study: Louisiana black bear groups intermingling
A black bear captured in Patterson.
BATON ROUGE (AP) — Louisiana’s black bears are making huge strides toward recovery as the state’s dis-parate populations appear to be intermingling, according to two researchers who are presenting their findings this week around the state.
Jared Laufenberg and Jo-seph Clark said work to restore bear habitat, particularly in the state’s delta region, has paid big dividends for the health of the population. Laufenberg studied Louisiana’s once-threatened bear population as part of his University of Tennessee doctoral dissertation.
They presented their find-ings Tuesday at public meet-ings in Baton Rouge and Lafayette, with other meet-ings scheduled Wednesday in Ferriday and Thursday in Tallulah.
Louisiana black bears once ranged throughout the Bayou State and into South Mississippi and East Texas, but by the 1950s, the distribution was profoundly reduced due to conversion of hardwood forests to croplands. The population dwindled to only 80 to 120 bears remaining in a tiny slice of the forested delta.
Although there is no official estimate for the size of the black-bear population throughout Louisiana, Clark and Laufenberg gave a rough guess of between 258 and 283 females combined in the Tensas, Upper Atchafalaya and Lower Atchafalaya populations.
State biologists in the 1960s brought 161 bears down from Minnesota as part of a restocking program, and by the 1990s, populations had become established in the Tensas River Basin, the upper Atchafalaya River Basin and the Lower Atchafalaya Basin.
To help the population re-cover further, officials en-rolled Louisiana black bears in the Endangered Species Act program in 1992, and published a recovery plan in 1995. The three recovery criteria were that there needed to be at least two viable populations, there had to be movement corridors between them and the habitat needed to be protected.
According to the infor-mation presented by Laufenberg and Clark, each of the goals appears to have been met.
“What is clear is that Louisiana black bears are in much better condition than 22 years ago when they were listed,” Clark told the crowd attending the presentation.
One of the many reasons is that state biologists from 2001 through 2009 trans-ferred some of the bears from the established Tensas River Basin population to the Three Rivers area to seed a “stepping-stone” population between the Tensas population and another distinct group of bears in the Upper Atchafa-laya Basin.
The plan has worked well, Clark explained. Bears have gotten well-established in the Three Rivers area, and the females have begun to intermingle with males from the Upper Atchafalaya Basin population. In general, female black bears disperse very little, while males roam great distances looking for mates. This trait has evolved to reduce in-breeding in bear populations, Clark said.
Because of the stepping-stone population in the Three Rivers area, the genes of the Upper Atchafalaya Basin bears have been found all the way up in the Tensas River population, Clark said.
“Without that Three Rivers population, I doubt we would have had any interchange between Upper Atchafalaya Basin and Tensas River Basin (bears),” he said.
Although males from the Atchafalaya Basin population are migrating up to Three Rivers, none from that area seem to be moving down to the Atchafalaya Basin, and the researchers are baffled as to why.
One possibility, Clark said, is that the bears are finding natural funnels moving in one direction but not the other.
Once the males get to the Three Rivers area, they’re finding easy pickings. The area is dominated by females because that’s mostly what biologists transferred there.
“The Three Rivers area was stocked with females that were producing cubs in the Tensas River Basin,” Laufenberg said. “That’s not a bad thing. If you’re going to stock a place, why not stock it with good numbers of females who are producing cubs?”
Those migrating males are doing a good job spreading their genes among the populations. Of 35 cubs recently tested in the area, 20 were sired by males that had come from the Upper Atchafalaya Basin population, Clark said.
The state’s population has just completed its breeding season, which is in June and July, Laufenberg said, and the females will give birth in January or February while they are denned up for the winter.