A low-hanging fruit for corridor conservation lies in riparian areas. People value riparian areas for conservation. These areas serve as buffers for rivers and streams that improve water quality. They are used as greenways for recreation.
Because of their value to people, conservation organizations have entire programs dedicated to linking communities with water conservation. The Nature Conservancy’s Water Funds initiative is a classic example. In conservation, we often think about how conservation of biodiversity leads to conservation of ecosystem services. Riparian butters flip this on its head: conservation of ecosystem services leads to conservation of biodiversity.
Conservation for biodiversity and for ecosystem services may not always align. When riparian areas are conserved as climate corridors, meaning that plants and animals may use them to shift ranges under increasing temperatures, then additional factors besides water quality must be taken into account.
Riparian areas can be potential climate corridors because they have physical characteristics that make them cooler than the surrounding landscape, such as lower elevation and higher tree cover. As they connect from river headwaters to outlets, they form an uphill path along which plants and animals can escape to cooler temperatures.
In a recent analysis, Meade Krosby and colleagues developed a method to prioritize riparian conservation. They used commonly available physical and geographical data across the Pacific Northwest to determine both the relative conservation value of and the relative threat to all waterways in the region. They calculated an environmental index that assumes that areas hold higher value if they are shadier, wider, higher in habitat quality, and less exposed to solar radiation.
A valuable aspect of their approach is the ability to identify riparian areas that have high potential conservation value but low levels of current protection. These areas will be particularly valuable in the future to facilitate range shifts, and can be designated as high-priority targets for investment in conservation.
The index they developed represents a uniquely pragmatic approach, as these high priority areas represent a tiny fraction of riparian forests, the bulk of which are made up of low quality habitat. By developing this novel method, they not only provide guidance for riparian management and restoration, but also for climate adaptation planning that can conserve both ecosystem services and biodiversity.
Krosby M, Theobald DM, Norheim R, McRae BH. 2018. Identifying riparian climate corridors to inform climate adaptation planning. PloS ONE 13(11):e0205156.