Climate change and human activity are going to combine to create new challenges to biodiversity in the coming century. Over the last decade, it’s become increasingly apparent that 20th century conservation strategies may be poorly suited to protect species in a changing world. Take the Endangered Species Act of 1973 — it’s a place-based, species-specific model that focuses on the protection of critical habitat as a central strategy. This has been tremendously useful, but it’s cumbersome (you need detailed, species-specific recovery plans, and there are a lot of species; also, this only covers the US). And there’s a problem: what happens when a species leaves its ESA-mandated protected area to track its optical climate? And how are we going to save a million species threatened by climate change with individualistic plans, especially if we don’t even know where a lot of them live and what they need to thrive? How are we going to pay for it all?
In the last decade, there have been a growing number of creative, but often controversial, conservation strategies proposed to deal with the challenges faced by biodiversity in a warming, fragmented world. There has long been debate in conservation about the scale of focus, particularly when it comes to charismatic, or “flagship” species. Strategies focusing on ecosystem services, rather than species or biodiversity per se, have also come under fire, because what can be valued can also be bought, sold, and compensated for. Still others advocate a more landscape-scale conservation, which can benefit from an umbrella-species approach focusing on large-ranging predators or megafauna like elephants or wolves, but these can be challenging when available protected areas are small and corridors are rare. Plus, charismatic, large-ranged species often provoke human-wildlife conflicts that make implementation difficult; people like cougars, but not everyone wants one in their backyard. And, ultimately, all of these approaches will be challenged by climate change, as species will try to track their habitats outside of protected areas.
One emerging strategy to deal with this challenge is to drop the focus on species, and instead use geological diversity as a surrogate for biological diversity. I’ve blogged about “conserving nature’s stage,” rather than the actors, as a way to protect biodiversity on evolutionary timescales. Areas with greater geodiversity — more soil classes, topographic heterogeneity, geologic features, water, etc. — have been shown to harbor more biological diversity, because they have a more diverse mosaic of habitats. They also tend to support more rare species, both because such species are often found in unique habitats (e.g., serpentine soils or cliffs). The idea behind a CNS approach is to leverage this pattern by protecting ares with high geodiversity, with the understanding that species — the actors — will come and go, but the stage — the geological setting — will persist. By protecting the “enduring features,” you can thus, in theory, protect evolutionary processes overall. This was the topic of a recent issue of Conservation Biology (Read here!), and there’s plenty of research that needs to be done on this topic, but conservation NGO’s like the Nature Conservancy are already getting on board.
For those not willing to give up on species as conservation units, growing concerns about climate change have triggered a lively discussion about the role humans should play in the managed relocation of species. I was part of the working group that came up with the term “managed relocation” as an alternative to “assisted migration” or “assisted colonization,” and I like our version because I think it’s more honest about what’s actually happening, while avoiding some of the normative or definitional problems with the other terms. Whatever you call it, the intentional movement of species into new geographic areas is something humans have done since, well, there were humans. In our working group, I was surprised to learn that the Forest Service has been actively practicing managed relocation, though not necessarily due to climate change, for decades. It’s also a central strategy of citizen science conservation groups like the Torreya Guardians, with a goal of saving a critically endangered conifer from extinction. While it remains controversial (Anthony Ricciardi and Dan Simberloff even went so far as to say it’s “not viable“), it may be the only way to help some species facing significant barriers to dispersal.
In the case where species have already been lost to extinction or local extirpation, the “extinction is forever” adage may soon no longer apply. When I started grad school in 2005, Pleistocene rewilding was the hot-button topic of the day, and as someone who works on the consequences of megafauna extinctions I was often asked what I thought about plopping elephants and lions down in the American Great Plains. While this idea has a lot of problems (not the least of which is that people live in the Great Plains and would probably like to be consulted), I actually think it helped start a lot of important conversations about the consequences of extinction, and the important keystone roles that many species have played in the past. It’s also, as Josh Donlan and other proponents have pointed out, a profoundly optimistic framework, which can be appealing in a crisis discipline. And while the original idea centered around replacing analogs of extinct species like mammoths and saber-tooth cats, rewilding can help us think about low-risk, high-reward opportunities, like using the Aldabra tortoise to disperse an endangered ebony on Mauritius.
Rewilding has an even more ostentatious cousin: de-extinction. Why use a surrogate when you can have the real thing? From woolly mammoths (or “mammothy elephants“) to the passenger pigeon, there are active efforts to use genetic tools bring extinct species back to life. Many have understandably challenged the validity of this approach, arguing that de-extinction is a misuse of rare conservation dollars, it doesn’t address the reasons those species went extinct in the first place, and it’s got limted practical value outside the lab. Proponents have focused on the scientific applications (what better way to know whether Neanderthals had the capacity for speech?), or the fact that de-extinction would be the equivalent of the moon landing for biology, as well as the conservation value. I’ve seen growing arguments that de-extinction isn’t just about bringing back something like the thylacine for its own sake; rather, we have an opportunity to, like rewilding, restore lost ecosystem functions — from seed dispersal to making the tundra more resilient to climate change. Resurrecting lost species sounds like science fiction, but it’s an active area of research. In my opinion, we need to think seriously about cloned species in terms of their own ecologies if we’re going to take this idea seriously, which is something I’ve felt has been largely lacking from the discussion. I’m less interested in a reconstructed woolly mammoth, but a more resilient tundra is something I could potentially get behind.
Ultimately, the challenges of the next century are going to require some novel thinking when it comes to conservation strategies. Each of the above involve active research and, in many cases, are already being applied, and I’m sure there will be even more out-of-the-box ideas to come. It’s easy to dismiss the solutions outlined as too wild to take seriously, but I think they’re provoking important discussions about the very nature of conservation and just how much intervention, change, dynamism, and, ultimately, subjectivity, we’re willing to accept to protect biodiversity for future generations.