Species will Need to Relocate when the Climate Changes and People may have to Assist them

Climate change is already having an impact on plants and animals around the world, and it is posing an increasing threat to biodiversity, adding to the existing issues of habitat loss, invasive species, pollution, and overexploitation.

A new study published in the April edition of Biological Conservation evaluated scientists’ recommendations for conserving biodiversity in the context of climate change, giving a summary of practical advise and highlighting areas where more research is needed.

“There is an enormous need to think ahead and be proactive, as well as a growing recognition that we have to act now,” said senior author Erika Zavaleta, professor of ecology and evolutionary biology at UC Santa Cruz.

Plants, animals, and entire ecosystems are at risk of becoming trapped in locations where they can no longer exist when the climatic conditions to which they have adapted alter across the geography of a warming globe.

“Climate change is causing a mismatch between where species are now and where the habitat and conditions suitable for them are moving,” Zavaleta said. “We need to think about where suitable habitats for different ecological communities will be in the future, and how they can get there.”

Climate change is not a new phenomenon in the history of our planet, and species have adapted to it. However, contemporary climatic changes are occurring at a considerably faster rate than previous climatic transitions. Furthermore, the current fragmentation of natural habitats makes it far more difficult for animals to migrate than it was previously.

“The need to move is greater while the ability to move is less,” Zavaleta said. “Things are changing, and we need to assist the adaptive responses of the natural world if we don’t want to lose both the species and the amenities they provide for people. We depend on natural ecosystems, and helping them adapt is not separate from helping people and communities adapt to climate change.”

Climate change is causing a mismatch between where species are now and where the habitat and conditions suitable for them are moving. We need to think about where suitable habitats for different ecological communities will be in the future, and how they can get there.

Erika Zavaleta

Zavaleta and Nicole Heller, a postdoctoral researcher in Zavaleta’s group at the time, released an earlier survey in 2009. The new study was led by Blair McLaughlin, an assistant professor of ecology at Hampshire College in Massachusetts who received her Ph.D. in Zavaleta’s lab and is currently a visiting scholar at UCSC.

Current recommendations, the researchers discovered, have gone beyond conceptual guidance to include more precise and actionable ideas regarding solutions to execute for certain ecosystems or species.

“There has been a lot more on-the-ground implementation of some of these approaches,” Zavaleta said.

In the face of climate change, long-standing conservation strategies such as safeguarding and restoring ecosystems and enhancing their interconnectedness remain crucial. However, three unique solutions have attracted increasing attention in recent years to solve climate-related challenges: climate change refugia, assisted migration, and safeguarding climate-adaptive DNA.

“If you think of a valley oak, with acorns that are carried only a short distance by birds and are only viable in the year they are dropped, you can have connectivity but the trees are not going to move at the same pace as the drying that’s happening in parts of their range,” Zavaleta explained.

“So do we watch their range contract and disappear? Or do we bank them as seedlings in botanical gardens? And what do we need to be learning now about how to put them back out into the landscape where they can survive?”

Identifying and protecting sites that can serve as refuges for species threatened by climate change is a simple matter of following the traditional biodiversity conservation paradigm. Habitat restoration initiatives, such as restoring forest streams to increase the water table, can be part of creating climate change refugia.

“Assisted gene flow,” which involves transporting animals between populations within a species’ existing range to conserve genetic diversity, as well as moving species beyond their historical range, is part of assisted migration.

However, this type of direct intervention to relocate imperiled species to locations where they may have a greater chance of survival in the future is fraught with controversy. Potential effects on other creatures following translocation are a concern, as is the risk of hurting the targeted population if translocated individuals do poorly in the new place.

“I feel like the devil is in the details, but I also think translocation has been mischaracterized as an untested strategy, when actually it has been practiced for over a century and probably longer,” Zavaleta said.

“Forestry, for example, has a long practice of planting trees from a wide range of locations in areas that are being restored. But we do have a lot more to learn, especially for certain animals and species that are not well understood.”

Scientists also aim to safeguard species’ genetic diversity, particularly genetic variants that may be better adapted to hotter, drier environments.

“These are the very conditions that we are likely to see more of in the future,” McLaughlin said. “Preserving the climate-adaptive evolutionary potential of a species before it’s lost is critical to make sure we have the genetic resources we need to help species adapt to novel climate futures.”

Oaks towards the southern end of their range or those that have survived a large die-off during a drought, for example, may have genetic features that help them survive under worsening conditions. Seeds and seedlings from certain trees could be saved in a “gene bank” to prevent the loss of those features.

McLaughlin is currently leading a pilot project in California to establish a gene bank for blue oaks, which were decimated in the southern portion of their range during the last drought.

“We’re planting out seedlings from blue oaks that are adapted to hot dry conditions, just so they’re banked there in case there are more die offs,” she said. “In California, it’s become clear that we need to do this now.”

In addition to McLaughlin and Zavaleta, the coauthors of the paper include Nicole Heller, now at the Carnegie Museum of Natural History in Pittsburgh, Sarah Skikne at the University of Minnesota, Erin Beller at Google, Rachel Blakey at UCLA, Rachael Olliff-Yang at UC Berkeley, Naia Morueta-Holme at the University of Copenhagen, and Brittni Brown at Payette National Forest in Idaho.

Topic : Article