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Texas ocelot breeding and reintroduction may offer new route to recovery

An endangered Texas ocelot (Leopardus pardalis)

An endangered Texas ocelot (Leopardus pardalis) surveys the thornscrub on private land in South Texas. Image courtesy of Fin & Fur Films.

  • A public-private partnership aims to establish a new ocelot population in Texas to ensure survival and recovery of the species in the U.S. Current ocelot populations at the East Foundation’s El Sauz Ranch and Laguna Atascosa National Wildlife Refuge are small, isolated and inbred. The nearest Mexican ocelots are 100 miles to the south.
  • The new Texas population can offer insurance against accidental extirpation due to a hurricane or disease and give access to now inaccessible habitat and dispersal corridors. Captive-bred ocelots, with a mix of genes from Texas and elsewhere, will be released on East Foundation’s San Antonio Viejo Ranch, west of the current range.
  • The effort represents the world’s second-ever attempt to release small wildcats via a captive breeding program. Without a suitable federal or state wildlife refuge for release, the Texas program will rely on a Safe Harbor Agreement to ensure buy-in from nearby landowners. Ranches in the region have a deep culture of wildlife management.
  • Distance, development and the border wall all make connectivity between U.S. and Mexican ocelots difficult — especially in the Lower Rio Grande Valley. The new release site represents the best possibility for connectivity, but continued border wall development could threaten movement of ocelots and other recolonizing species.

KINGSVILLE, Texas — That ocelots (Leopardus pardalis) are native to the United States may come as a big surprise to many people. But the small wildcats, more commonly associated with Central and South America, once ranged across much of the Southwestern U.S., though today they survive in only two small populations isolated on the Texas Gulf Coast — totaling fewer than 100 individuals and beginning to suffer from inbreeding.

That could be about to change, as an ambitious new agreement between the US Fish and Wildlife Service (USFWS) and several state and private partners aims to return the endangered ocelot to parts of the species’ historic range.

The plan: Breed the animals in captivity, then reintroduce them to the wild in hope of establishing a new population in a larger patch of good habitat 75 miles west of the current ones (see map). This reintroduction could secure the future of ocelots in the U.S. against a potential disaster like a hurricane or disease outbreak and offer opportunities for them to recolonize more of their former range on their own.

The new population would also be free from some of the daunting obstacles encircling the coastal populations, such as agricultural expansion, home building and road construction.

But the reintroduction faces challenges. It will take place entirely on private lands, without a large wildlife refuge or park to anchor the new population. In addition, while dispersal corridors to Mexico’s ocelot population are still open to the west, construction of the border wall by federal, state and even private actors could one day seal off these connections.

A Texas ocelot photographed by camera trap deep within thornscrub at the El Sauz Ranch
A Texas ocelot photographed by camera trap deep within thornscrub at the El Sauz Ranch, part of filmmaking efforts for 2022’s American Ocelot and Deep in the Heart. Image courtesy of Fin & Fur Films.

A new model for ocelot restoration

The initiative, dubbed Recover Texas Ocelots, brings together nine partners, including federal and Texas state agencies, private foundations, zoos and veterinarians. The project grew out of more than a decade of intense collaboration among government biologists, university scientists and private partners who studied U.S. ocelots via camera traps, radio collars and other methods.

Ocelots currently persist in just two U.S. populations along the Gulf of Mexico in South Texas, north of the mouth of the Rio Grande and the U.S.-Mexico border. The larger population is centered on the privately owned El Sauz Ranch, with a smaller population in the Laguna Atascosa National Wildlife Refuge. Ocelots have suffered heavy mortality around Laguna Atascosa due to road collisions, and the two populations no longer exchange individuals.

This lack of gene flow has dire implications: Both populations appear to be becoming inbred. Conservationists have long emphasized the need to grow the populations and improve connectivity between them and, ideally, link them with the larger, more diverse gene pool in northern Mexico. But with little suitable habitat nearby and key dispersal corridors being lost to development and wall construction, Texas ocelot conservationists are looking farther west, where far more habitat exists and dispersal is less restricted.

Map of ocelot habitat in South Texas

The reintroduction plan will rely heavily on the nonprofit East Foundation, which owns the El Sauz Ranch, and on the foundation’s 150,000-acre San Antonio Viejo Ranch to the west, between Hebbronville and the border — the proposed new home for released ocelots. Another key partner is the Cesar Kleberg Wildlife Research Institute (CKWRI) at Texas A&M University, Kingsville, which specializes in wildlife conservation and management in the brushland habitat critical to ocelots.

As a first step to establishing a new population, USFWS awarded CKWRI a $12.2 million contract to operate a captive breeding program. The source breeding cats will come from zoos and, perhaps in the future, from the wild in northern Mexico, where ocelots are closely related to the Texas animals. The partners are pursuing breeding techniques that include artificial insemination, which could unlock the benefits of genetic mixing without removing any Texas cats from the wild.

Release and survival in the wild may be the biggest hurdle for the effort, as wildcats typically learn survival skills from their mothers. Reintroduced “animals are going to have to learn to hunt, move around the vegetation, socialize with each other, and not get close to humans.” In other words, “to act like normal wild ocelots,” says Lindsay Martinez, a research program coordinator for the East Foundation.

The Texas reintroduction will be an experiment in many ways: To date, only one small cat species, the Iberian lynx (Lynx pardinus) in Spain and Portugal, has ever been successfully reintroduced via a captive-bred population. The partners have written an extensive handbook to guide ocelot captive breeding and will soon break ground on breeding facilities, but no time frame has been given for the first release.

East Foundation scientists and partners study a tranquilized ocelot before returning it to the wild at the El Sauz Ranch
East Foundation scientists and partners study a tranquilized ocelot before returning it to the wild at the El Sauz Ranch in Willacy County, Texas. Image courtesy of East Foundation.

Boxed in on all sides

Ocelot habitat in Texas currently means essentially one thing: thornscrub, a dense, spiny jungle of low-growing trees and shrubs that makes surprisingly good wildlife habitat. But much of this diverse subtropical brushland has been cleared to improve grazing lands or permit development. While good Texas habitat persists where the two remaining U.S. ocelot populations dwell, these islands are cut off on all sides. To the east is the Gulf of Mexico, while roads, homes and agricultural lands lie north and south.

To the west lies the South Texas Sand Sheet, also known as the Wild Horse Desert, one of the most enigmatic and little-known ecosystems in the United States. The Sand Sheet’s 3,000 square miles of dunes and grasslands, an area larger than the state of Delaware, form an imposing barrier for a small cat that doesn’t like to leave dense cover.

The East Foundation’s San Antonio Viejo Ranch, the intended ocelot reintroduction site, lies west of this sandy desert and contains large tracts of thornscrub and good potential for ocelots to expand deeper into the cats’ historical range in Texas — and possibly all the way to the nearest Mexican populations.

But there are multiple hurdles to reconnecting any U.S. and Mexican ocelot populations. The first is distance; the nearest Mexican populations are at least 100 miles from the current Texas populations, far south of the border. The second is development, which has isolated the two U.S. populations from each other and from suitable habitat farther west. The third factor is the border wall, which reinforces the developmental barrier in the Lower Rio Grande Valley and may one day cut off remaining development-free corridors.

Public agencies spent a significant amount of money acquiring private lands for conservation along the Rio Grande, saving some of the best potential habitat for ocelots from conversion to citrus plantations or homes. “The federal government and private partners, both private landowners and nonprofit organizations, have spent hundreds of millions of dollars over the last decades working on connectivity in the Lower Rio Grande Valley,” says Sharon Wilcox of the NGO Defenders of Wildlife. Funds were often raised by passionate wildlife advocates who wanted to see ocelots use the wild corridor in the future.

But despite USFWS spending more than 45 years and about $82 million to acquire 105,000 acres of refuge land in the Lower Rio Grande Valley, none of these preserves are likely to host ocelot movement in the future. That’s because sprawling McAllen and Brownsville are among the fastest-growing cities in Texas, and they, along with cities on the Mexican side of the river, prevent Texas ocelots from dispersing into or through these refuges. Also, the border wall now cuts right through several riverside refuges, destroying habitat and connectivity.

In many places, the pace of development has made the border wall a moot point for ocelot connectivity. “In my opinion, the likelihood of an ocelot leaving Mexico, entering into the United States and getting into the U.S. ocelot population — with or without a wall — is zero,” says Ben Masters, a conservation filmmaker who led the team that captured the camera trap footage featured in PBS’s American Ocelot. But others see a remaining pathway to the east, along the coast, where a potential border wall could make all the difference.

“The dreamers in our community continue to think about long-term connectivity back to Mexico,” says Wilcox. “If you follow the Rio Grande all the way to its mouth, we do not have a border wall there, and that is because of some very hard-won fights on Capitol Hill.”

Wilcox says this “Ocelot Coastal Corridor” could succeed with effort by conservationists in both the U.S. and Mexico. But even if a wall can be prevented, industrial development threatens the dream. In 2021, Defenders of Wildlife lost an action against a liquified natural gas terminal that has since consumed a significant chunk of habitat in the corridor. Also, SpaceX has raised environmental concerns by building rocket launchpads in the middle of the Lower Rio Grande Valley National Wildlife Refuge.

These barriers possibly played a role in USFWS and its partners turning their eyes west, where habitat connectivity is higher and developmental pressure lower. Ocelots repopulating the San Antonio Viejo Ranch, for example, could conceivably recolonize much of their range in South Texas. The distance to Mexican populations, however, would remain daunting — and be impossible to bridge if wall construction continues.

Thick thornscrub
Thick thornscrub, seen here at Laguna Atascosa National Wildlife Refuge, characterizes the remaining ocelot habitat in South Texas. Roads have been a significant source of ocelot mortality in and around the refuge. Image courtesy of Defenders of Wildlife.

The Texas wall: A work in progress

In California, Arizona and New Mexico, where U.S. borderlands are almost entirely federal, successive administrations faced little resistance to erecting new barriers. Now, almost the entire border from the Pacific Ocean to El Paso, Texas, is marked by some form of wall — of debated utility in stopping human migration but effective at halting animal movement.

The situation is different in Texas. Despite Texas occupying two-thirds of the entire U.S.-Mexico border, most of its international boundary is, for now, completely without barriers other than the Rio Grande itself. This is due to a long history of individual ownership, in Texas dating back to Spanish land grants of the 1700s. Outside of the refuges in the Lower Rio Grande Valley, almost all land in South Texas is privately owned. Few landowners wish to see a wall through their property, which would cut off access to the river and clear-cut habitat for a mandatory 150-foot enforcement zone.

Because almost every mile of wall built on private land requires an expensive and protracted legal process of condemnation, the wildlife refuges on state and federal land along the Rio Grande were the first and easiest places for wall construction. Now, a set of refuges originally established to permit wildlife connectivity are instead becoming an essential piece of the U.S.’ longest, most restrictive wildlife barrier.

Border Patrol at work along the border levee and wall in McAllen, Texas.
Border Patrol at work along the border levee and wall in McAllen, Texas. The Biden Administration has frequently cited “levee repair” as a reason to upgrade border infrastructure in the Lower Rio Grande Valley. Image courtesy of Donna Burton.

Despite the difficulty of building a wall farther upriver in Texas on private land, many in the American political system remain dedicated to doing so. While President Joseph Biden promised not to build “another foot” of wall, his administration never ceased condemning private land in Texas. Recently, Biden waived 26 federal environmental and historical preservation rules to permit further construction in the Lower Rio Grande Valley, becoming the first Democratic president to do so.

Through “Operation Lonestar” the state of Texas also began building its own border wall and installed floating river barriers labeled “death traps” after several drownings. National political forces have also raised funds to build private sections of wall with cooperative landowners, such as a segment adjacent to the National Butterfly Center in Mission, Texas. That contractor was recently awarded $224 million by Texas to build walls in Laredo.

As the Texas walls fill in the refuge system and creep outward from border cities, the flow of human migrants — and attention of lawmakers — is likely to shift westward to the great unwalled expanses of thornscrub farther up the river.

Border wall construction proceeding along the Rio Grande in June 2023, near the National Butterfly Center in Mission, Texas.
Border wall construction proceeding along the Rio Grande in June 2023, near the National Butterfly Center in Mission, Texas. Image courtesy of Defenders of Wildlife.

A second chance for ocelots

While the lack of public land west of the Lower Rio Grande Valley has provided an unexpected benefit to wildlife connectivity, it poses some challenges for wildlife reintroduction. The reestablishment of a carnivore without a large chunk of public land to anchor the effort (protected in perpetuity and managed directly by an environmental agency) is uncharted water for USFWS.

Luckily for ocelots, the ranches of South Texas are exceptional among U.S. private lands for existing as such large units of contiguous habitat. This wild landscape is popular with hunters who stalk white-tailed deer (Odocoileus virginianus) and bobwhite quail (Colinus virginianus). A strong conservation ethic has developed around sustainable wildlife management in conjunction with ranching, and in this remote area, where the same families have often worked the land for more than a century, conservation means stewarding productive rangelands for the next generation. That may be good news for reintroduced ocelots.

USFWS ocelot species lead Laura de la Garza acknowledges how unusual it is not to have public land available for a release but is excited about this innovative partnership with conservation-minded landowners. “Things are done a little differently in Texas, and that’s not necessarily a bad thing,” de la Garza says. “This really opens the door to working with private landowners to study other species.”

One novel engagement strategy is a Safe Harbor Agreement offered to landowners who fear restrictions on livelihood due to the introduction of an endangered species. Under the agreement, neighbors of the San Antonio Viejo Ranch who allow ocelots to disperse onto their land, and provide access to help monitor them, will not be required to change their land management practices — and will not be liable if an ocelot accidentally dies.

The importance of stakeholder engagement is underscored by the tragedy of one recent carnivore reintroduction. Over a period of two decades, USFWS painstakingly reintroduced red wolves (Canis rufus) to North Carolina, anchored by the Alligator River National Wildlife Refuge. But, after climbing to a population of about 100, USFWS suspended releases, and many wolves leaving the refuge were shot due to anti-predator or anti-federal sentiment. The population has now fallen to fewer than 30, with the program nearly back to square one. USFWS has been court-ordered to begin releasing wolves again.

While ocelots, unlike wolves, don’t pose a threat to livestock, they could face persecution if hunters develop a perception that the wildcats are depressing quail numbers. Texas is famous for its enthusiastic predator hunts, and nearly every predator species, including bobcats and mountain lions, can be hunted year-round, day or night, on foot or from a vehicle, with almost no limit. So far, there have been no incidents of Texas ocelots being persecuted, but all populations currently occur on dedicated conservation properties.

An ocelot in thornscrub at the El Sauz Ranch.
An ocelot in thornscrub at the El Sauz Ranch. Fewer than 100 ocelots remain in the United States, in two populations centered on the Laguna Atascosa National Wildlife Refuge and the private El Sauz Ranch to its north. Image courtesy of Fin & Fur Films.

If USWFS and its partners can ensure positive landowner engagement and long-term buy-in from the ranching and hunting community, then the closure of one door in the Lower Rio Grande Valley may lead to the opening of a new door farther west. All sources for this article say they agree that there is currently excellent habitat and connectivity for ocelots to expand from the San Antonio Viejo Ranch toward the U.S.-Mexico border and spread over much of their former range.

“There’s still a lot of country, particularly between Del Rio and Laredo, that doesn’t have a wall, and right now we’re seeing bears and mountain lions come across the border and recolonize their historic habitat. Those are both really exciting opportunities that we have as Texans to see these amazing animals come back to our state,” says Masters, who traveled the length of the Texas border in 2019 for his film The River and the Wall.

That hopeful conservation scenario, however, requires that activists and conservationists not give up on the idea of wildlife connectivity between the U.S. and Mexico, even in the face of bipartisan pressure to build more wall. And there’s another reason to hope for a successful reintroduction: In a state with so much private land, lessons learned from the ocelot partnership could be applied to other species to help conservation move forward, in Texas and in other states. “I think that what the East Foundation and partners are doing on private lands could be a really good model,” says Martinez, “to come up with some innovative stuff for the next decades of the Endangered Species Act.”

Banner image: An endangered Texas ocelot (Leopardus pardalis) surveys the thornscrub on private land in South Texas. Image courtesy of Fin & Fur Films.

In South Texas, watch out for ocelots crossing roads (commentary)

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