Image by Thomas R Machnitzki, Wikimedia Commons
Ever since I began giving serious consideration to what specific steps can be taken by landscape planners and designers in response to climate change, I have been thinking about refugia. I first encountered this term as a university student when it was used to describe a place near my hometown. I grew up in the vast, flat inner coastal plain that follows the Mississippi River northward from the Gulf of Mexico. I had never thought of this landscape as being particularly special for its botanical bounty, so I was surprised to learn that one of my favorite places – the forested bluffs along the Mighty Mississippi – provided refuge for species during the last Ice Age. That discovery has given me a curious sort of pride in my hometown landscape ever since! The Botanical Institute of Texas describes the refugia along the Mississippi like this:
During the ice age, many plant species shifted southward, and at glacial maximum around 18,000 years ago, boreal forest reached Arkansas, with spruce and tamarack in the Tunica Hills along the cold, foggy Mississippi valley. Deciduous forests of oak and hickory extended to the Gulf of Mexico. As the glaciers retreated and the climate warmed, pines and other species from refugia in Florida, along the lower Mississippi River, and southern Texas and northern Mexico, spread across the southeast.
As we contemplate the opposite movement of species, the northward shift, we must begin to identify and protect places of refugium. Major land conservation organizations like The Nature Conservancy are already engaged in this sort of planning exercise as they account for climate change impacts on the lands they manage. Federal land management agencies are also considering ways to provide refuge to species, in part because of a 2009 executive order by President Obama that mandated integration of climate adaptation planning into all agency planning activities. These are positive steps, but, like all conservation activities, they need to extend beyond public lands and private conservation lands to have the greatest effect. This is where planners and designers can make a contribution – considering the potential for refugia on privately held land in communities across the country. It’s the next step in environmentally sensitive areas planning and an opportunity to “mainstream” climate adaptation into ongoing community planning and design.
In its simplest form, “hot-surviving” refugia are found on the northern slopes of hills and mountains, at higher elevations, in mountain coves and hollows (known as “hollers” in another place I’ve called home), and in deep canyon recesses. The good news? These places are very easy to identify in the landscape! The next steps, a bit more difficult. In another post, I will discuss a related topic, the controversial idea of assisted migration.
