Ecological Drought

The majority of tools available for drought monitoring, forecasting, and assessing impacts focus on drought in relation to human food and water supplies. However, some research suggests that using these common meteorological or hydrological drought indices “can result in mischaracterizing the severity and impact of ecological drought.” The limited number of tools and data available for monitoring, forecasting, and assessing ecological drought may be due, in part, to the challenge of measuring complex ecological systems, a lack of historical ecological data, and the relative paucity of comprehensive datasets on ecological systems. As a result, there is limited understanding of the ecological changes over long periods of time that can result from drought and of the magnitude or persistence of these impacts from droughts of different levels of severity or duration in different locations. 

Recently, the scientific gaps in our understanding of when and where processes that maintain ecological stability will be overwhelmed and drought-induced ecological transformation might occur were identified (Crausbay et al. 2020). Examples of knowledge gaps include the need to predict mortality events, to understand how ecological community assembly will unfold under the now unfamiliar climates of drought recovery, and to know when common management tactics to resist ecological transformation might fail, or on the other hand, when tactics could be directed to allow ecological transformation along a particular trajectory.

Recent research on planning for ecological drought highlights that, while some planning processes acknowledge ecological drought, they rarely identify or assess the vulnerability of all ecological aspects in a landscape that stakeholders value. Recent research and practice have been developing new approaches and tools, such as identifying and estimating costs of ecosystem service losses, that can be incorporated into planning for drought and other hazards. For example, nature-based solutions seek to sustainably manage, enhance, or restore ecological systems, with the goal of maintaining, enhancing, and/or realizing co-benefits of ecosystem services (e.g., forest restoration to reduce urban flood impacts and provide for recreation). Similarly, water management approaches that integrate environmental flows into planning seek to address ecological water demands in addition to agricultural, industrial, and other water demands.

The U.S. Geological Survey (USGS), through its national and regional Climate Adaptation Science Centers, has led early efforts to examine the effects of ecological drought across the country. Its Ecological Drought initiative supports the management of ecosystems and human communities in the context of drought, by identifying and synthesizing knowledge of the ecological impacts of drought, communicating that knowledge, and strengthening decision-making to prepare for and respond to drought. To help meet this aim, NIDIS was proud to serve on the SNAPP Ecological Drought Working Group, focused on understanding the natural and human dimensions of ecological drought impacts, and promoting the application of solutions that provide mutual benefits to people and nature. To learn more, view the USGS story map, Ecological Drought Across the Country.

A recently-funded NIDIS project, led by Conservation Science Partners, Inc., seeks to better understand ecological impacts of droughts by strengthening our understanding of ecological drought vulnerability and translating and delivering that information for drought planning processes.