Climate change is the most challenging of future threats to the natural landscapes that make up the Escalante River Watershed (ERW). A proper understanding of the natural structure and function of the numerous ecological communities that are contained within the ERW is needed to mitigate the impacts of climate change. The diversity of habitat types, ranging from desert scrub at lower end of the watershed to sub-alpine forests on the Dixie National Forest (NF) on the north gives this watershed extraordinary ecological diversity. This diversity and the generally undisturbed condition of the landscape was one of the primary reasons why the Grand Staircase-Escalante National Monument (GSENM) was established to promote basic and applied science on a scale that is possible in few other places. While not originally a primary target of science within the GSENM, the rapidly increasing pace of a shifting climate now makes climate change studies a clear priority.
Below are examples of some of the more important climate-change related issues that are expected to challenge future management of the public (and private) lands within the ERW. The hope is that ERWP science programs can contribute to successful solutions.
Water Dependent Communities
Water is the essential limiting resource over much of the ERW. In many places, especially in the lower regions of the basin, perennial water sources are limited to small springs and seeps (and hanging gardens) (examples below). These vital resources are poorly understood, incompletely inventoried, and their future under various climate change scenarios has yet to be adequately assessed. This important task is now the primary focus of the ERWP Springs Committee. The Escalante River and its tributaries are the major sources of permanent water within the watershed. The Russian olive removal project, pursued over more than two decades, has been ERWP’s flagship restoration initiative. The Riparian Restoration Committee has overseen successful efforts to clear this invasive tree from large stretches of the Escalante River. The longer-term goal has now shifted to ecological restoration of native riparian habitats and monitoring the recovery of these systems. A key element of the monitoring will be to understand how and to what extent climate change is affecting (and perhaps limiting) the recovery process. Our Native Fish and Wildlife Committee will be an essential partner in this monitoring effort.
Local water sources consisting of perennial springs and seeps are among the most critical natural resources within the Escalante River Watershed (ERWP). Their response to climate change is a high science priority for the ERWP. Springs and seeps are found on all three of the major public land administrative units within the watershed. Examples seen here are (left to right) a seep supporting hanging gardens (Glen Canyon National Recreation Area) and springs with open pools on the Grand Staircase Escalante National Monument and the Dixie National Forest. Photos by J. Spence (left, middle) and D. Bramble (right)
The vast majority of native plant communities within the ERW are best regarded as “upland”, in that they are not associated with or directly dependent on free surface water. Collectively, these ecosystems represent well over 90% of the area within the ERW. Assessing the impact of climate change on such a large area and diverse assemblage of natural communities will be daunting. Only a few of the issues specific to upland communities are mentioned here. These are all nominally within the purview of the Uplands Restoration Committee.
Forested Ecosystems. Forested ecosystems are widespread within the ERW and are currently a major focus of management policy (in both USFS and BLM). Pinyon-juniper (P-J) woodlands dominate the lower elevations and are the only significant forest type within the GSENM. Ponderosa pine and mixed conifer forests occupy the middle and higher elevations on the Dixie NF at the north end of ERW. Scattered populations of bristle-cone pine are found at the upper-most elevations. Virtually all these forest types suffer to some degree from decades of inadequate management (e.g., fire suppression). Currently there is a concerted effort to improve the health of these forested ecosystems thorough selective harvest (i.e., thinning), prescribed fire and various “treatments” of P-J woodland. Most projects are designed to reduce the risk of catastrophic wildfire. The potential effects of climate change on forest communities have not, until recently, been a central factor in management decisions, but will increasingly have to be taken into account. For example, there is now a growing evidence to suggest that in many places the wholesale removal of P-J woodland will promote conversion to permanent shrubland, thereby eliminating the life-sustaining benefits that many native species depend upon. Similarly, very recent studies have emphasized the importance of forest overstory structure on understory micro-habits where the majority of forest species most vulnerable to climate change reside. Thus, climate change considerations need to inform future forest management, including logging operations, tree thinning, and restoration protocols. In the spring of 2021, the first clear indications of climate-driven mortality of Utah juniper (the Southwest’s most drought resistant tree) began to appear within the ERW.
Ecological Migration. Another anticipated consequence of climate related shifts in temperature and precipitation on upland habitats is the “migration” of not only individual species but of entire communities to more favorable locations. The dominant relocation strategy within ERW will almost certainly be movement into areas of higher elevation, cooler temperatures and greater precipitation. For species already restricted to the highest elevations (e.g., pikas, bristle cone pines) there may be no viable refugia. Appropriate long-term monitoring of both the distribution and population dynamics of such sensitive species will necessarily be an integral component of future climate change studies. In cases where migration routes are naturally blocked, active relocation (i.e., “assisted migration”) might be considered as the only viable conservation effort for the most vulnerable of species.
Anthropogenic Impacts. One factor that certainly merits greater attention is the extent to which human activities degrade an ecosystem’s natural ability to resist the stresses of climate change (e.g., prolonged drought) and the resilience that allows it to recover normal function once the stress dissipates. Activities that are widespread within the ERW (e.g., livestock grazing, roads, recreation, various rangeland improvement projects) will need to be examined more closely in light of the extra burden placed on native ecosystems by a changing climate (i.e., increasing temperatures certainly and quite possibly reduced precipitation). Reduced ecological resistance often paves the way for exotic species to invade native ecosystems, thereby elevating the risk of subsequent decline of these natural communities and the extirpation of associated species.