“Health is the capacity of the land for self-renewal. Conservation is our effort to understand and preserve this capacity.” Aldo Leopold, 1949, A Sand County Almanac
Aldo Leopold, a forester and father of the conservation movement, may have gotten it right 60 years ago — long before quickly changing climates were recognized as a serious threat to the diversity of life on our planet.
Leopold’s wisdom is holding up against recent research, says Mark Anderson, Science Director for The Nature Conservancy’s Eastern U.S. region. His cutting-edge findings are shedding light on why some places host an extraordinary array of plants and animals — setting the geographic stage for far more diversity than other places — and what this means for conservation in an age of climate change.
Anderson, who recently shared his findings at a training seminar for the U.S. Fish & Wildlife Service, is seeking to share lessons for how practitioners — those who “do” conservation in the field — can continue to protect landscapes, rivers, wetlands, forests and coasts even as these natural settings change with the climate.
Instead of focusing on one or two species in a landscape to save, Anderson says scientists are now wondering: how can conservation “create arenas for evolution, not just museums of the past?” In other words, how can we boost nature’s inherent resilience? And how can we allow nature to change, but still maintain a diversity of plants, animals and benefits to people?
Anderson calls this goal “conserving the stage” for different actors. Or if you’re a baseball fan, check out this video in which Anderson visits Fenway Park in Boston to explain his research in terms more meaningful to a Red Sox — or even a Yankees — fan.
Preserving Arenas for Nature’s Game
In baseball, star players with various talents are traded onto the team and appear on the field to play a very specialized role in the game, not unlike the variety of species that live together in natural places or move through them. And in conservation, a network of diverse natural places – much like a league of ballparks – must be preserved from year to year to provide the infrastructure for nature’s game to play out.
The Northeast has seen dramatic shifts in plant and animal life since European colonization, as wildlife like the wolf and cougar, and trees like the chestnut (source of sturdy lumber used to frame early barns and homesteads), are no longer present in the region. Nonetheless, certain landscapes still harbor a great richness of plant and animal life.
Common conservation wisdom holds that the species occurring in a particular place are largely determined by the climate. While this is true at a broad scale, Anderson, a community and landscape ecologist, was surprised when his analysis of 14 states and three provinces found this: at the scale of a single state, the number of plants and animals present was more closely related to the variety of geologic settings (coastal sands, limestone valleys, granite mountains, silty floodplains) than to the temperature or precipitation.
“It appears that physical settings play a strong role in creating and maintaining diversity” and changing climates add another layer of complexity, Anderson says. Species richness of each state was highly correlated with four factors: the number of geological classes, latitude, elevation range and the amount of calcareous bedrock.
For example, in the Eastern U.S. (Virginia west to Ohio and north to Nova Scotia), many rare species are restricted to landscapes with calcareous bedrock – a chalky geological layer containing calcium carbonate or limestone. Among the region’s 388 rare species (out of 13,530 known species) found most commonly in calcareous bedrock landscapes, are:
- ferns like the Limestone Adder’s-tongue,
- mussels such as the Spiny Riversnail,
- amphibians like the cave salamander,
- fish such as the Tangerine Darter and Yellowfin Madtom,
- reptiles like the Lake Erie Water Snake
- and even a couple mammals – bats like the Gray Myotis and the Virginia Big-eared Bat – that utilize the caves typical of limestone landscapes.
These findings led Anderson to rethink his earlier work co-authoring a national vegetation classification system. But, that’s the process of science. “Nature often surprises me,” he says with a smile.
So, if we can’t move bedrock, what can we do to help manage our nature preserves and other important landscapes as the climate changes rapidly?
Anderson believes his research underscores some of the principles of the Conservancy’s planning process, Conservation by Design: making sure you have “enough of everything” to keep nature functioning as a whole. We may need to account for one more factor of diversity — geophysical settings — when identifying high-priority places to protect.
Even if temperatures warm or rainfall increases, some geological settings will continue to be ideal places for new “players” or species to move in and thrive. The key, says Anderson, is to have a network of these places distributed along latitudes so there are enough refuges for plants and animals to find new homes as their optimal temperature zones move north.
Anderson says he now realizes that current natural communities are an expression of how nature’s processes and physical settings come together at a place. These settings (just like good old Fenway) remain important even as the climate and occupant plants and animals (or this season’s ball players) change over time.
Lisa Hayden is a blogger and feature writer for The Nature Conservancy
Photo © Stephen Alvarez, TNC (A cave salamander, or Eurycea lucifuga, usually found in caves around limestone outcroppings).
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