Land use and climate change alter the habitats of long-term Wisconsin species

November 5, 2014 |

Blandings tutrle
The Blanding's Turtle is one of Wisconsin's many species that have to adapt to changes in habitat.

In wetland pockets across Wisconsin, the eggs of the Blanding’s turtle are hatching in the warmth of early autumn. Many of these hatchlings will mature and lay eggs of their own in 20 years. However, the Wisconsin they face may be hotter, more humid, and peppered with extreme storms and summer droughts, according to climate scientists.

Changes in land use are also likely to affect Blanding’s turtles, which are listed as a species of “special concern” by the Wisconsin Department of Natural Resources. Without intervention, these turtles – Wisconsin natives since the Pleistocene – will have to adapt or migrate faster than they ever have before, or they’re likely to vanish from the state.

“The effects from human activity are so great and the rate of climate change so rapid, that many species must adapt, move, or die,” says paleoecologist Jack Williams, director of the Nelson Institute Center for Climatic Research at the University of Wisconsin-Madison and a WICCI affiliate.

Williams says “novel ecosystems” -- combinations of plants, animals and conditions never seen before -- are the result of forces such as urbanization, introduction of exotic species, agriculture and climate change.

So how can natural resource managers do their jobs in this rapidly changing environment? Consulting the historical record is a traditional first step. Measuring how fast species like Blanding’s turtle can adapt or migrate in real time is nearly impossible, so conservation strategies have often relied on historic baselines as benchmarks for preservation or restoration. These baselines sometimes date back to the post-Ice age Pleistocene beginning 20,000 years ago, long before 7 billion humans spread across the planet.

“People are creating new land-use patterns and demographic, economic, and political realities,” says Volker Radeloff, professor of forest & wildlife ecology at UW-Madison. “The future looks less and less predictable and unlike the past, historical baselines may no longer be a firm basis for management. What do these unpredictable and unprecedented changes mean for future biodiversity, for sustainability, and for conservation?”

Radeloff recognized an immediate need to shift the traditional management mindset away from restoring ecosystems to idealistic historical baselines. To help ecosystem managers prepare for and adapt to conditions unlike those of the past, Radeloff leveraged a portion of a 5-year, National Science Foundation Integrative Graduate Education and Research Traineeship (NSF-IGERT) grant to launch a seminar titled “Novel Ecosystems.”

With Williams as co-leader, the seminar met last spring. The class of graduate students, post-doctoral fellows and faculty worked through the intellectual and practical foundation for managing novel ecosystems. They examined the economic and political mindsets that can conflict with long-term needs for preserving biodiversity and ecosystem integrity. Discussions covered plausible ways to assess the risks a given species or ecosystem might face, and methods that could be used to assist survival of a particular species.

“A key lesson from the past is that when climates changed, each species went its own way,” says Williams. But according to Williams, “We don’t see a lot of extinctions over the past million years, even with the glacial advance and retreat.”

Throughout the semester, seminar participants worked through emerging management scenarios, taking into consideration socioeconomics, species invasions, changing pathogens, changes in water and nutrient cycles, methods for endangered species conservation within ecosystems in flux, and vanishing suitable habitat. The group also examined the role that protected areas and landscape corridors could or should play as escape routes for trapped species to move to more fitting climates. And they examined the suitability and relevance of current laws and regulations that now must be viewed in the context of rapid ecological and climatic changes.

eastern massasauga rattlesnake
The WI DNR plots out the Blanding's Turtle's ecological landscape association scores. Dark purple represent strong association.

More often than not, management quandaries will not involve charismatic species that frequently receive media attention. Instead, researchers and land managers will grapple with economically important species such as commercial and sport fish, as well as long-time, but discreet residents in Wisconsin such as the Blanding’s turtle.

A recent study completed by Christopher Hamilton, a doctoral candidate co-advised by Radeloff and Anna Pidgeon, assistant professor of forest and wildlife ecology at UW-Madison, compared high and low climate change-rate scenarios with land use change predictions. Hamilton discovered that while projected land use changes such as urbanization would normally be the main challenge, Wisconsin’s rapid rate of climate change is now a bigger factor. He found that within 35 years, Blanding’s turtles will most likely have suitable habitat only in the northern third of the state.

Possible intervention strategies could include creating a set of stepping stone-like habitat patches -- a little habitat archipelago -- that provides safe passage for turtles moving north, or a breeding population could be moved into new habitats in northern ecosystems, where they will be newcomers.

The rate of climate change is now so rapid that many organisms that were once able to migrate on a glacial time scale -- such as Blanding’s turtle -- cannot move fast enough. Managers now must decide, without historical guideposts, when and how to intervene.