The Nature Conservancy's Center for Science and Public Policy in Arizona was created to engage stakeholders and expertise in applied science and policy to develop new information, ideas, and tools that can help solve some of our most pressing challenges affecting people and nature.
This study used a long-term dataset to examine the impacts of drought on grassland conditions at Las Cienegas National Conservation Area in southeastern Arizona from 2004-2014. Changes included declines in perennial grass basal cover with patchy mortality, leaf litter increases, shrub declines and increases in non-native grass, Lehmann’s Lovegrass (Eragrostis lehmanniana). Grassland cover declined by 25-50% in years with low precipitation from January-June. Given that global climate models predict steep declines in spring rainfall, grassland managers could improve grassland resilience by monitoring rainfall and associated mortality across multiple months, including non-traditional seasons, and by establishing contingency plans for various types of drought. The dataset was developed through a partnership between The Nature Conservancy and Bureau of Land Management with monitoring assistance from stakeholders.
This article examines the influence of climate variability and accelerated forest thinning on runoff in ponderosa pine forests in the Salt and Verde River watersheds in central Arizona. The effects of thinning treatments were examined over 15-, 25-, and 35-year periods. Over the course of treatments, cumulative runoff on thinned forests was about 20% greater than un-thinned forests, regardless of whether forest thinning occurred in a dry or wet period. Runoff gains were temporary and modest when compared to total annual flows in Salt-Verde (≤3%). Nonetheless, additional runoff from thinning could help offset projected declines in snowpack due to warming, augment river flows on a seasonal basis, improve conditions for water dependent natural resources, as well as provide incidental benefits to downstream users.
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