Adapting Restoration Techniques to Meet Climate Challenges on the Gila River
Alexia Osornio1, Melanie Tluczek2, Steve Plath3
1Gila Watershed Partnership of Arizona, Safford, AZ, USA; lexi@gwpaz.org
2Gila Watershed Partnership of Arizona, Safford, AZ, USA; melanie@gwpaz.org
3Gila Watershed Partnership of Arizona, Safford, AZ, USA; steve@gwpaz.org
One of the primary challenges for restoration in arid climates is helping young plantings succeed under increasingly dry conditions. The past few years have seen sustained drought and record high temperatures in the Upper Gila Watershed, making it more difficult to grow young trees in an already water-stressed system. This challenge is compounded by factors such as river diversion, increased wildfire frequency, and competition from invasive plants, particularly tamarisk (Tamarix spp.), a highly invasive riparian tree. Even as these challenges make restoration more difficult, the need for restoration along the Upper Gila River has become even more urgent since the arrival of the tamarisk leaf beetle (TLB; Diorhabda spp.). The TLB was first detected in the Upper Gila Watershed in the summer of 2020, and over the next few years it is expected to defoliate large swaths of tamarisk along the river. As tamarisk declines in response to beetle activity, it is critical to establish islands of native trees and other plants that can support local wildlife in the absence of tamarisk. Creating such islands has been one of the primary goals of Gila Watershed Partnership (GWP) since 2014. Over the last few years, GWP has experimented with a variety of restoration techniques to promote survival and establishment of its native tree plantings. In particular, irrigation of young plants has shown considerable promise for encouraging root growth and facilitating groundwater access. Here we discuss the three primary irrigation methods used by GWP, lessons learned from each, and recommendations for how to choose an appropriate irrigation method at riparian restoration sites.