Restoration in Response to Invasive Species, Climate Change, and Altered Stream Flows That Can Support T&E Species and Higher Biodiversity in a New Environment
Thomas G. Whitham1
1 Merriam-Powell Center for Environmental Research, Northern Arizona University, Flagstaff, Arizona, USA; Thomas.Whitham@nau.edu
With the simultaneous challenges of invasive species, climate change, and altered stream flows, restoring riparian habitat for threatened and endangered species and to maintain high biodiversity has become more challenging than ever before. In a relatively stable environment, planting with local stock is scientifically sound, but with a rapidly changing environment altered by invasive species, climate change, and altered hydrology, the riparian environment has changed so much that local stock may no longer be locally adapted and the use of local stock will become an increasingly bad practice that is likely to result in high establishment mortality, low naturally occurring future recruitment, and low growth rates that support low biodiversity. In short, a rapidly changing environment results in a mismatch between the local stock and the new environment. Because of great genetic variation in cottonwoods and willows to invasive species, climate change, and altered stream flows, using field trials of the NSF funded Southwest Experimental Garden Array (SEGA), we can identify the plant genotypes and source populations that are best suited to survive and regenerate in a wide range of future conditions and specific restoration sites. These naturally occurring plants differ in their drought tolerance, deep rooting behavior, microbial mutualists, architecture, insect diversity, competitive ability with invasive species, adaptive plastic responses to environmental change, and other functional traits that make them better suited to a specific site than the local stock. The use of these plants is the focus of a new genetics-based strategy that emphasizes restoration for current and future environmental conditions rather than past environmental conditions. With the success of restoration projects costing millions of dollars at stake, we need the most advanced science available to minimize project risk and obtain effective long-term restoration.