Epilogue: The Future of Endangerment

Epilogue: The Future of Endangerment

by Lisa H. Sideris

To be threatened is to be at risk of endangerment; to be endangered means to be at risk of extinction. The ultimate goal of listing species as threatened or endangered is to one day remove them from such lists. The process of removal, called delisting, can occur because a species has gone extinct or because it has achieved recovery. Fortunately, the percentage of species delisted for reasons of recovery exceeds that of removals owing to extinction—though not by much. Perhaps a more appropriate way to view these outcomes is the frequently cited statistic that 99 percent of species placed on threatened and endangered lists are successfully prevented from going extinct. 

The process of recovery that aims at delisting can take many years or even decades. Before legal protections for threatened and endangered species can even commence, a species must first make it onto the list, an undertaking that is often painfully slow, replete with bureaucratic hurdles, funding challenges, and ultimately constrained by the need to juggle complex priorities and competing claims of various species in need of protection. On average, species wait twelve years to be listed, and they can wait as long as thirty-seven years or more. Thus, by the time species attain protected status, their numbers may have dwindled to the point of near-extinction. 

Recovery is a long game. Yet, length of stay is not necessarily a sign of poor prognosis or inefficiency. In one of the most notable conservation success stories, the iconic Bald Eagle spent forty years on the federal Endangered Species Act (ESA) list as endangered or threatened before being delisted in 2007. Critics of endangered species protections, however, often suggest that species languish on ESA lists for far too long and at unnecessary expense, like pampered, freeloading guests who have overstayed their visit. On April 18, 2025, President Donald Trump’s Secretary of the Interior Douglas Burgum likened the endangered species list to the “Hotel California,” complaining that “once a species enters, they never leave.” (Never mind that the hotel guests in the song Burgum references suffer from self-entrapment, “prisoners … of [their] own device.”) Yet despite decades of such complaints from conservative pundits, various lobbyists, and others, very few pieces of legislation are as successful, or as popular with a broad, bipartisan public, as the Endangered Species Act. 

As conservation success stories go, the El Segundo blue (ESB) butterfly—now nearing fifty years on the endangered species list—is a promising candidate, even as new threats are emerging for endangered species protection in general. Protections for endangered species are guided by recovery plans that are periodically reviewed and updated. In June 2025, a group of student researchers collaborating on a senior practicum under the direction of UCLA environmental scientist and urban ecologist Travis Longcore released a painstaking and ambitious ten-year recovery plan for the El Segundo blue. Despite great reductions over the years in the butterfly’s historic range, from over 1000 hectares to only around 115, its numbers have now improved to the point that within the next decade, the ESB may qualify for downlisting (reclassification from endangered to threatened) and even delisting, if additional criteria are met. The plan notes that the LAX preserve and the Chevron site, along with the Ballona wetlands, “appear to be in the best conditions across population status, habitat condition, and legal protections.” 

Were the butterfly to be delisted, it would be the first insect species removed from the endangered species list owing to recovery. The butterfly’s story might serve as a hopeful and inspiring narrative—not only for insects, whose challenges tend to receive relatively less attention, but for conservation more generally. Restoration at the LAX Dunes Preserve, the recovery plan notes, “serves as an inspiration for ecological resurgence in a highly urbanized area.”

The ESB’s close ties to its local habitat—its relative lack of mobility and its reliance on a single plant—can expose it to threats to which other butterflies are less vulnerable. Its hostplant, as we have seen, requires very specific conditions to thrive and is easily destroyed by invasive plants and development. At the same time, while other butterflies may enjoy less stringent habitat requirements, behaviors like migration can subject them to different risks. Because migration requires the successful alignment of many factors, the sensitive timing of which is easily disrupted by climate change, migrating creatures are especially susceptible to human-caused environmental pressures. For example, scientists believe that the fires that ravaged Los Angeles in early 2025 contributed to a sharp decline in migrating western monarchs during the most recent overwintering season. Monarch sites at Lower Topanga Canyon were particularly hard hit by the fires that scorched overwintering groves.

A proposal to list monarchs as federally threatened was launched in December 2024, just a month prior to the catastrophic fires. The final decision on that proposal is expected in December 2025. As with endangered and threatened species protections generally, federal listing would grant protections against what is known as “take,” defined broadly in the ESA as harassment, harm, pursuit, hunting, shooting, wounding, killing, trapping, capturing, or collecting. The definition of take also applies to actions that could significantly modify or degrade habitat, given that habitat destruction can also lead to the death of organisms by interfering with their ability to find food, shelter, and mates.  

While the ESB was spared these recent climate-fueled disruptions owing to its restricted range and flight season (in mid-late summer), some startling developments in 2025 raised new potential threats to the butterfly and indeed to all species granted protected status. In particular, protection from “take” and the definition of what it means to harm a protected species have become a target of the second Trump administration in its efforts to roll back protections.

For decades, the above-mentioned definition of take has included harms that occur directly to an organism, such as killing or injuring, as well as “indirect” acts that negatively impact habitat. Under the Trump proposal, the definition of harm would now exclude habitat protection. The narrower definition of harm, in other words, would fail to protect the places where species live and the resources they need to survive—despite the well-established evidence that habitat loss, destruction, and fragmentation remain the key drivers of species endangerment and extinction. Public comment on the proposal—which garnered significant interest among citizens and the media—ended on May 19, 2025. As of this writing, the status of the proposal remains uncertain, with no particular timeline announced for the final decision. 

This proposed change to the established definition of harm can be viewed alongside other recent developments in conservation science and genetic technologies. Just ten days prior to the announcement of the proposal to rescind the longstanding inclusion of habitat under the definition of harm, the billion-dollar biotech firm Colossal announced what it claimed was a “de-extinction” of the dire wolf: a canine species that vanished approximately 13,000 years ago. Claims of de-extinction have been widely disputed by scientists and others who point out that the resulting creatures are simply gray wolves with a number of genetic modifications to make them resemble the extinct species.

What these two developments have in common is their disregard for the places where species make their homes. Efforts to “resurrect” extinct species, for example, tend to discount the relationship between organisms and their environments—where they feed, hunt, breed, and interact with other lifeforms—as integral to their history and identity. If species were not so closely intertwined with their natural environments, it might be reasonable to view lab-created or genetically engineered organisms like the dire wolves as viable substitutes for endangered or extinct animals. Consider that the original prey species of true dire wolves are themselves largely extinct. The wolf versions created by Colossal are hand-fed a special diet of kibble; they will never leave their enclosure in a highly secured, undisclosed location, to interact with other wild animals or procure their own food (perhaps a closer analogue to the Hotel California scenario that troubles Secretary of Interior Burgum). Nonetheless, Colossal markets these laboratory creations as acceptable stand-ins for the genuine article.  

Significantly, on the very day of Colossal’s announcement of an alleged dire wolf de-extinction, Burgum took to social media with lavish praise of de-extinction technologies, touting what has become the mantra of his “environmental” vision—innovation over regulation—and questioned the need for an endangered species list. “Pick your favor species, and call up Colossal,” Burgum advised. Soon thereafter, the Trump proposal to remove habitat from the definition of harm to endangered species was announced. In short, the same dubious logic that bolsters hyperbolic claims about the dire wolf “de-extinction”—and praise thereof—also animates the proposal to redefine harm. Both treat species as if they live in a vacuum

The Trump proposal decenters the importance of the places species call home at a time when habitat destruction is happening at unprecedented rates. These changes, if they stand, would constitute a seismic shift in protection of endangered and threatened species. How might they impact the El Segundo blue? 

Given that the El Segundo blue butterfly has lost significant habitat to development and faces continual threats from invasive species that outcompete its hostplant, a narrower definition of harm that rescinds habitat protection could reverse decades of progress toward recovery. At first glance, it appears likely the proposal would make it harder to halt development projects that damage or degrade the butterfly’s habitat and would likely give regulatory agencies less authority to intervene in activities that damage habitat but do not constitute an immediate and observable threat to its mortality (as with directly injuring or killing organisms). On the other hand, the butterfly’s hyperlocal existence and close ties to its hostplant might become especially important here in ways that might help protect it. Compared to species that range broadly, where theoretically one could destroy a portion of habitat without the actual “take” of individuals, it is virtually impossible to “take” ESB habitat without also killing individuals. For a species whose entire lifecycle is spent on a single type of plant, rarely straying more than sixty meters from it, taking the habitat is taking the individuals—an immediate and observable threat. The line between indirect and direct harm is, for all intents and purposes, nonexistent.

The longstanding, broader definition of harm has withstood previous challenges. In a 1995 case in which a coalition of landowners, logging companies and timber workers challenged the ESA’s definition of harm, the U.S. Supreme Court upheld the government’s inclusion of habitat modification as within the scope of “take.” Legal challenges to the Trump administration’s current proposal to rescind the existing definition of harm are virtually guaranteed. For now, these efforts to weaken protections for endangered and threatened species create significant uncertainty, just as the El Segundo blue butterfly is emerging as a symbol of hope and a rare conservation success story for the insect world. 

Masthead image: The colorful Saguaro Hotel in Palm Springs, California, 2013. Photo by Carol M. Highsmith. Source: Wikimedia Commons.