Biotechnology Is a Powerful Tool for Conservation

Chestnuts, rats, and rhinos illustrate how biotechnology could transform conservation

By Emma Kovak

What do the American Chestnut tree, the black rat, and the northern white rhinoceros have in common? They are all prime targets for conservation through biotechnology. Genetic engineering could give American chestnut trees disease resistance and restore the keystone species to Eastern forests, gene drives could eliminate rats from islands and save seabirds from the invasive predators, and assisted reproduction technology could rescue the Northern white rhinoceros from the brink of extinction.

The U.S. Department of Agriculture is poised to approve an American chestnut engineered to resist the blight that functionally eliminated the species from Eastern forests. Meanwhile, the International Union for Conservation of Nature (IUCN)—the world’s largest conservation network—is voting on whether to ban biotechnology outright or recommend thoughtful case-by-case evaluation.

These decisions are important determinants of biotechnology’s role in the conservation toolkit. With extinction rates accelerating, conservation efforts should be able to use as many tools as possible.

The biodiversity crisis

The scale of the biodiversity crisis is staggering. Roughly 1 million species are currently threatened with extinction—or roughly 12% of all estimated existing species. In comparison, the IUCN suggests that almost 2,500 species have gone extinct or have likely gone extinct in the last 500 years after assessing just 2% of all species.

Islands bear the brunt of extinctions, and host 40% of globally threatened vertebrates. Invasive species are by far the most common cause of island extinctions, and rats are the most frequent culprits. Rats threaten seabird populations around the world, and are currently the cause of extinction threats for at least 75 species on 60 islands. Seabirds on these islands evolved in the absence of rats and are vulnerable to predation of eggs and chicks, with small, burrow-nesting species most affected. Some islands have completely lost their seabird populations, with cascading effects on both island and ocean life.

In Eastern forests a century ago, the American chestnut tree was a keystone species. Before the blight arrived, there were an estimated 4 billion American chestnut trees in North America. At a mature forest density of 100 trees per acre, 4 billion trees would cover 20 million acres—an area larger than the U.S. state of Georgia. These trees provided both wood for timber and plentiful nuts that fed humans and other animals, including squirrels and bears. In the late 1800s, chestnut blight—which arrived with imported trees from Asia—tore through the population of American chestnuts in just 50 years, leaving only scattered stump sprouts that continually succumb to blight and never grow into trees.

In 1960, northern white rhinoceroses numbered 2,000 across Sudan, the Democratic Republic of the Congo, and Uganda. Humans have been poaching the rhinoceros for decades and selling their horns, which diminished the population to two infertile females. The last male northern white rhinoceros died in 2018, so the population can no longer reproduce on its own.

Existing conservation tools are essential, but they can be too slow, too blunt, or too costly relative to the current pace of change and the size of conservation challenges. Poisoning rats is very effective at clearing them from an island, but has ecological, financial, and other constraints, and is particularly challenging on large islands. Captive breeding can stabilize a species, but for some animals—like the northern white rhinoceros, reduced to two infertile females—natural reproduction is impossible. Against this backdrop, it’s not just reasonable but necessary to ask whether biotechnology can add what conservation often lacks: precision, scalability, and genetic rescue from extremely dire circumstances.

What biotechnology offers conservation

Biotechnology can support conservation by restoring resilience, controlling harmful populations, and rescuing species on the brink of extinction. The American chestnut needs resistance to blight in order to thrive, and coral need the ability to live in warmer oceans due to climate change. Like controlling harmful rat populations can help restore seabird populations, biotechnology approaches to reducing invasive zebra mussel populations could support native mussel populations. And while the northern white rhinoceros population may be rescued from the brink of extinction by in vitro fertilization, scientists have used cloning of preserved cells to reintroduce genetic variation into the black-footed ferret population.

In response to the challenges of exterminating invasive species on islands, organizations like Island Conservation that have used traditional methods for years are participating in the Genetic Biocontrol of Invasive Rodents consortium to genetically engineer gene drives into mice and other invasive species to reduce or eliminate their populations on islands. A gene drive rigs genetic inheritance so harmful traits—like infertility in invasive rats—spread rapidly through populations, potentially offering more precise control than poison baits.

The American Chestnut Foundation (TACF) has been working for over 30 years to bring back the trees using mainly non-biotech conventional breeding approaches that incorporate blight resistance from Chinese chestnut trees. The foundation has updated its conventional breeding practices to include genomic selection and speed breeding, and the New York chapter of TACF has been using genetic engineering to introduce resistance for almost as long. The genetic engineering approach, conducted by the foundation in partnership with the SUNY College of Environmental Science and Forestry (SUNY-ESF), yielded somewhat blight-resistant trees years ago—though the two organizations disagree about how effective the trees submitted to USDA are. TACF expects to produce blight-resistant trees using conventional breeding in the next 20 years.

The northern white rhino population is past the point where captive breeding or artificial insemination approaches could help. BioRescue is attempting to revive the critically endangered species using in vitro fertilization (IVF)—with sperm frozen during the last living male rhinos’ lifetimes—and embryo transfer into a southern white rhino surrogate to create the first northern white rhino born in over 25 years.

Considering the scale of conservation challenges—habitat loss, invasive species, extinctions, and more—all tools should be on the table. Yet, biotechnology has been and continues to be highly controversial, with ongoing debates among environmentalists, scientists, and conservationists.

Among conservation practitioners and stakeholders specifically, differing perspectives are evident in two opposing motions being debated by the IUCN. The IUCN has been working for years towards a position of cautious case-by-case consideration of biotechnology applications for conservation, and members are currently debating between two opposing motions: one that lays out this cautious approach and one that calls for an outright ban on the technology. Organizations like Greenpeace have been and remain vehemently anti-GMO, but others like the Sierra Club—once famously against GMOs—made a significant reversal when it commented in support of the genetically engineered American Chestnut.

As some environmentalists continue to debate whether to use biotech for conservation at all, others must consider what these projects need in order to succeed. Though its journey is far from complete, the over 30-year history of the GE American Chestnut—the biotech product for conservation that is the closest to release—holds some important lessons for biotechnology for conservation more broadly.

The chestnut test case

In 2020, SUNY–ESF petitioned USDA to allow planting of the genetically engineered chestnut trees beyond research plots—the first such request for a genetically engineered organism for conservation. TACF and SUNY-ESF, partnered to submit the petition to USDA, but when SUNY-ESF discovered a mix up of different lines of the trees in 2023 TACF withdrew support over disagreements with SUNY-ESF—including over the performance of the specific line of trees submitted to USDA. After the mix up, SUNY-ESF revised its petition to clarify which chestnut variety was under review. Now, five years later, the final comment period on USDA’s assessment of the petition has closed, and the next step should be a final decision by the agency.

There are three main lessons to be learned from the American Chestnut story about regulatory gaps, effective engagement, and integration of biotechnology with other conservation approaches.

First, current biotechnology regulations in the US are for crops, not conservation. Assessing the safety of biotechnology for conservation is more complicated than for agriculture because it involves release into more varied and complex environments. Federal biotechnology regulatory agencies are not well prepared to assess products for conservation use or wild release—as opposed to agricultural environments—and the vast majority of their experience is with biotechnology for agricultural and confined industrial use. For example, USDA and FDA spent years deciding which agency would lead regulation of the genetically engineered Oxitec mosquito for malaria control, and by the time they settled the matter the company had moved on to conducting trials outside the U.S. Other gene drives to control invasive species may face similar hurdles. This means developers must prepare for a prolonged approval process and to work closely with regulators.

While there is progress to be made in federal regulators’ ability to assess these types of products, their authority is limited and assessments are in large part up to land owners, conservation practitioners, and local regulators. The federal biotechnology regulatory agencies—USDA, EPA, and FDA—look for risks to plant health, the environment, and human and livestock health, but do not assess the effectiveness of the GE organism in achieving conservation goals. As part of USDA’s review of the American Chestnut, the agency conducted NEPA analysis that considered the impact of the genetically engineered trees on everything from forest animals to air quality. But USDA’s approval of genetically engineered organisms hinges only on one potential risk—the likelihood of the organism becoming a plant pest or worsening the impact of existing plant pests. In this case, USDA’s NEPA analysis is solely procedural because the agency does not have authority to reject the product based on any of the additional factors considered in the NEPA analysis.

Second, effective engagement in decision making around the use of biotechnology for conservation can improve projects and build legitimacy. The Sierra Club’s comment in support of the genetically engineered American chestnut argued that the benefits of the chestnut outweigh the risks, and that the potential environmental risk from release is very low. It also highlighted constructive feedback, including that the chestnut should be continually monitored in more wild settings, and should not be released without consent from indigenous peoples who live within its former range. This type of careful consideration and constructive engagement from a range of environmental organizations is important to strengthen applications of biotechnology to conservation and to build diverse coalitions to support projects.

Third, biotechnology is just one tool among many for pursuing conservation goals and must be integrated with other approaches. The American Chestnut project, for example, is much larger than the single biotechnology approach undergoing review at USDA—it involves multiple approaches to creating trees with resistance, including conventional breeding with crosses to the disease-resistant Chinese chestnut, preserving genetic diversity from the small remaining wild trees, and multiple approaches to genetic engineering. Northern white rhino conservation involves in vitro fertilization, which depends on biobanking of gametes from living individuals, and genetic rescue for other species depending on their situation is through cloning or other assisted reproduction techniques.

Two decision points for the future of conservation

USDA’s decision about whether to allow planting of the genetically engineered American chestnut outside of confined trials will set a precedent for biotechnology for wild release. And the IUCN’s decision on motions urging a ban on biotechnology for conservation vs a cautious case-by-case approach will send a signal to researchers and product developers about how likely their technology is to be put into practice. If the IUCN votes for prohibition, the decision would foreclose the use of potentially beneficial technologies and could have a chilling effect on research on biotechnology for conservation. If USDA approves the chestnut and IUCN votes for a pragmatic process, researchers and product developers will see that genetically engineered organisms for wild release and conservation use can both make it through the federal regulatory process and face thoughtful consideration from a significant portion of the conservation community.

Environmentalists do not need to blanket approve the use of biotechnology for all conservation interventions, but they should be open to careful use when appropriate. Valid concerns warrant oversight, not bans. Traditional conservation carries risks too—captive breeding can reduce genetic diversity, and invasive species control sometimes harms non-target species. The relevant question isn’t whether biotechnology is risk-free, but whether its potential benefits justify careful deployment where conventional approaches have failed or are infeasible?

We must judge tools by their performance rather than by ruling out entire categories based on ideology. The world’s most threatened species and ecosystems cannot afford any less.