In the second of a four-part series that seeks to raise awareness of ecological drought, Rachel Gregg, senior scientist with EcoAdapt, shared her thoughts on how to strengthen an ecosystem’s resilience and mitigate the impacts of droughts, and how to plan and prepare for future droughts.
The series was co-hosted by NOAA’s National Integrated Drought Information System and the USGS National Climate Adaptation Science Center, with expert speakers from the research community, tribal nations, and government agencies.
Gregg said ecological drought is “the episodic deficit in naturally available water that drives ecosystems past their thresholds of vulnerability, and can affect ecosystem services.”
That means increases in wildfire frequency and severity, adaptability to disease and insects, increased invasive and non-native species abundance.
“Ecosystem services are also affected by ecological drought,” she said. “Such as reduced water supply, quality, reduced habitat, extending forage and reduced livestock carrying capacity due to increase in plant mortality reduces vegetation cover and increased soil erosion.”
When it comes to adaptation, she means trying to reduce negative effects or taking advantage of potential opportunities because of the changing climate and adaptation “helps you think about your investments of time and money over the long-term.”
“So really it is that intentional and explicit integration of climate considerations into what it is that you’re doing,” she said.
When going through the adaptation planning process, one may decide whether or not to continue an existing management action or decide to alter an existing action, or do something completely different.
“Or you may actually develop and implement new or novel actions,” she said.
That might look like protecting and restoring existing forest habitat or restoring forest habitat using drought tolerant species or creating a forest habitat at higher elevations—something that could be likely to help maintain cooler or moister conditions.
“A truly climate informed approach would really be to do a mixture of all three to hedge your bets about what approach will be most effective in a changing climate,” Gregg said.
In one of her research projects, Gregg wanted to try to synthesize findings around the effectiveness of ecological drought adaptation actions.
“So we first identified ecological drought adaptation actions,” she said. “We then review the scientific and grey literature—so looking at agency reports, project websites and tools to try and identify available evidence behind the factors that contribute to the success and longevity of these adaptation actions.”
Ranking factors
Later a consultation with an expert panel ranked each action according to its effectiveness, reduction of vulnerability and feasibility in terms of implementation. Criteria for the implementation feasibility included technical, financial and others, and data had to show if there were enough of these criteria in order to implement.
“And also the more factors—the social, cultural, institutional or legal factors you’re able to integrate or implement adaptation with limited barriers,” she said.
In this particular project, more than 260 ecological drought adaptation strategies and actions were identified when reviewing options generated and prioritized during regional adaptation workshops.
“We then streamline that list to try and combine approaches that aims to mean similar objectives and reducing vulnerability to ecological drought,” she said.
Gregg looked at various adaptation plans and once the expert panel and reviewers had their chance to review the findings and provide insight on how effective and feasible the plans were she was able to issue a report.
“Conservation and management approaches typically focus on the persistence of current conditions or restoration to some historical condition or climate change is going to force us to reconsider that business as usual approach,” Gregg said.
Management under climate change has its challenges and, because of that, there’s a continuum of approaches that have to be considered. From managing or promoting the persistence of the system to managing for change and managing for the future.
“These adaptation technologies are fairly common,” she said. “In all cases you’re managing for some desired condition which depends on your values as well as your risk tolerance.”
There’s a couple of bonus options that help determine the strength of the plan—intentionally choosing to observe ecosystem shifts and then taking no action.
“You’re trying to identify the best available information and then improving collaboration,” she said.
Ecological drought adaptation strategies
Gregg said one of the first steps was to try to identify some of the overarching goals of ecological drought adaptation. One of those is to reduce the sensitivity of ecosystems to water deficit.
“So trying to reduce stress on habitats and species; trying to facilitate species persistence under drought conditions,” she said.
Another is to retain ecologically available water in the system by creating or maintaining the system water supply, and limiting or preventing withdrawal of water. Also increasing the understanding about ecological drought impacts and adaptation.
“And then we tried to group these according to the adaptation topologies, and try to group those goals into which adaptation approach they really fit,” she said. “Such as walking through some of these resistance strategies. Do those strategies tend to have the goal of trying to maintain relatively unchanged conditions? So a lot of these are focused on prevention or protection.”
They’re typically short-term approaches because climate change is forcing us to change that business as usual approach, Gregg said. Some examples from her project include: protecting groundwater dependent habitats and species, things like exposures and fences; reducing tree density; infrastructure burns; and reducing water withdrawals.
“Resilience strategies have a goal of accommodating some change, but urging return to some prior and desired condition (like) reducing stress,” she said.
Examples of restoring habitats include maintaining native vegetation cover, removing invasive species, enhancing natural water storage and creating ample water supply.
“Our transition strategies are helping you to intentionally accommodate change by easing the transition from some current to some future state,” Gregg said.
These are strategies like identifying and protecting drought refugia, actively planting and storing seed from drought tolerant species and assisted migration.
“And then our knowledge and collaboration strategies to use best available knowledge and to promote water conservation through collaborative agreements like water banking, water trading and voluntary reductions,” she said.
Her goals for reducing stress on ecosystems and species have lead to a couple strategies. For example in a livestock situation where rotation and diversification is used to reduce pressure on vegetation and soils, she aims for a couple of things.
“My stock rotation and diversification helps spread risk within drought affected areas by reducing grazing pressure,” Gregg said. “Which can expedite post drought vegetation recovery and shifting the breed class or species of livestock on rangelands may ameliorate the effects of drought while maximizing production capacity under drought conditions.”
One of her findings was that sheep and goats are more heat tolerant and need less water than cattle. Drought can reduce forage nutrition and Gregg said those species, in addition to bison, are less selective when it comes to forages than cattle.
“There are some options available to people who are cattle ranchers or ranchers in general to diversify their livestock,” she said.
Another tool being used more and more to reduce grazing pressure on rangelands in the western United States is grass banking.
“These are cooperative conservation agreements that essentially incentivize ranchers to rest areas of pasture on their property in exchange for grazing access on other properties,” Gregg said. “This practice dates back to the 1990s, when Arizona, New Mexico collaborated, to try and support ranchers who were suffering from drought.”
Grasslands have also been used to preserve space for other conservation benefits, including wildlife habitat and conservation easements.
Gregg said her goal of retaining ecologically available water in the natural system is enhanced with the previously mentioned strategies.
“So retaining water and ecosystems through that natural water capture and storage can help reduce the effects of ecological drought,” she said.
Water retention can be facilitated with things like beaver dams, green infrastructure, large woody debris and rock structures. These practices can help empower water and retain sediment, which ultimately helps promote higher water tables and groundwater recharge, as well as increased water storage in surrounding soils.
Another goal is to help facilitate species persistence under drought conditions. For this she focused on creating or enhancing the existing water supply. This could include things like natural rock basements, artificial catchments, natural springs or wells.
“They’re all designed to ameliorate the loss of naturally occurring water sources for the benefit of not just wildlife but also agrarian species and livestock,” she said.
Water locations can influence the distance animals have to travel for water and ultimately their distribution. Some species might persist in sites more vulnerable to drought, but adding water developments could benefit animals during drought and help with distribution and grazing pressure. Gregg is concerned about these developments because of the potential increased competition between wild and domestic animals, animal mortality for those who become trapped in the developments and water quality.
“For the most part, there’s a lot of pros and cons associated with these,” she said. “In addition there are capital investment and long term maintenance considerations and managers have to take into consideration if we’re going to proceed.”
The use of snow fencing and other structures that force drifting snow to accumulate in a specific area have been used before and can help benefit local water sources and soil water content.
“It can be structural—horizontal or vertical slats like an actual fence or natural using grasses shrubs, trees,” she said. “Those vegetation barriers in particular can enhance snow retention, increase soil moisture in the local area and extend water yield availability.
Ecological drought doesn’t happen in a vacuum, and it’s just one factor practitioners have to deal with. Gregg said to consider it one for climate adaptation. She said to think about it like investment bankers do with a portfolio.
“You want to think about using a broad suite of options in order to try and spread your risks and resources across a range of opportunities,” she said. “Adaptation requires collective action to really be successful. You want to try to avoid mal adaptation, so pay attention to unintended consequences and effects on other sectors that may be complimentary or competitive.”
One sector’s “great adaptation strategy” may not work for another, so try and balance those.
“And also be creative and remember that adaptation is an iterative process,” she said. “As we do more research like this we may learn that different strategies are more effective in certain cases than others.”
For more information about the webinar series on ecological drought, visit www.drought.gov.
Kylene Scott can be reached at 620-227-1804 or [email protected].
