Cougar gene pool is still shal­low

A male puma that crossed I-15 sired 11 kit­tens, but sci­en­tists say more ge­netic di­ver­sity is needed.

Los Angeles Times - - CALIFORNIA - By Louis Sa­h­a­gun

Seven male cougars have crossed In­ter­state 15 near Te­mec­ula over the last 15 years, and one sired 11 kit­tens. Wildlife bi­ol­o­gists are heart­ened by this be­cause it demon­strates that a sin­gle male can en­hance ge­netic di­ver­sity among in­bred cougar pop­u­la­tions.

The fact that only one man­aged to re­pro­duce, how­ever, also shows how tough it is to di­ver­sify the gene pool in the small, iso­lated pop­u­la­tions of moun­tain lions re­main­ing in the Santa Ana Moun­tains, ac­cord­ing to a study pub­lished in May in the on­line jour­nal Royal So­ci­ety Open Sci­ence.

Now the re­search team led by Win­ston Vick­ers, a vet­eri­nar­ian at the UC Davis Wildlife Health Cen­ter, is propos­ing a puma con­ser­va­tion net­work along a twom­ile stretch of the free­way, com­posed of wildlife cor­ri­dors, bridges and im­prove­ments in un­der­passes cur­rently oc­cu­pied by homeless camps.

An es­ti­mated 20 moun­tain lions prowl the Santa Ana range, a land­scape frag­mented by de­vel­op­ment and high­ways.

Vick­ers said there are a num­ber of eco­log­i­cal rea­sons to pro­tect the big cats.

“Re­mov­ing the top preda­tor could have se­ri­ous cas­cad­ing ef­fects all the way down the food chain to birds and plants,” he said. “Moun­tain lions help con­trol pop­u­la­tions of deer, coy­otes, rac­coons and other species.

“From the hu­man per­spec­tive, in­creas­ing num­bers of deer could po­ten­tially lead to more col­li­sions

with ve­hi­cles.”

Moun­tain lions are not threat­ened or en­dan­gered in Cal­i­for­nia, but they are legally clas­si­fied as a “spe­cially pro­tected species” by the De­part­ment of Fish and Wildlife. The statewide pop­u­la­tion of about 6,000 is rel­a­tively sta­ble.

One of the largest moun­tain lion pop­u­la­tions in South­ern Cal­i­for­nia is con­fined within 275 square miles in and around the Santa Mon­ica Moun­tains Na­tional Re­cre­ation Area, which is bor­dered by the Pa­cific Ocean, ma­jor free­ways, hous­ing and com­mer­cial de­vel­op­ments, and agri­cul­tural fields.

Stud­ies sug­gest that that ter­rain, which is bi­sected by In­ter­states 405 and 101, may have reached its car­ry­ing ca­pac­ity with two or three adult male lions, four to six fe­males and some kit­tens. In­breed­ing is a se­ri­ous prob­lem among these big cats, who have ex­tremely low ge­netic di­ver­sity.

“In South­ern Cal­i­for­nia, we have dif­fer­ent moun­tain ranges — the Santa Mon­i­cas and Santa Anas — where lion pop­u­la­tions are sep­a­rated by free­ways,” Vick­ers said. “En­abling lions to cross the free­ways safely could help these strug­gling pop­u­la­tions stave off ex­tinc­tion.”

On Wed­nes­day, a moun­tain lion was struck and killed while at­tempt­ing to cross I-15 near the Te­mec­ula Creek bridge, Vick­ers said.

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