Spring Ecosystems Monitoring 4FRI

Introduction

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The Four Forest Restoration Initiative (4FRI) aims to restore 2.4 million acres of ponderosa pine and mixed conifer forest across four national forests in northern Arizona. Historical land use, such as grazing, logging, and fire exclusion practices, have resulted in overgrown forests that increase the severity and frequency of climate-change induced wildfires. The multi-stakeholder 4FRI is working to improve these forests’ climate change climate change
Climate change includes both global warming driven by human-induced emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. Though there have been previous periods of climatic change, since the mid-20th century humans have had an unprecedented impact on Earth's climate system and caused change on a global scale.

Learn more about climate change resilience by reducing the risk of severe wildfires through treatments such as mechanical thinning and controlled burns. These treatments are also predicted to increase groundwater infiltration, improving springs’ habitat within the area. 

Springs are keystone ecosystems in the Southwest (Tobin et al., 2018). These unique ecosystems, where groundwater reaches and usually flows from the Earth’s surface, may be the only reliable water source in arid regions. Groundwater provides perennial and seasonal flow to streams; drinking water for wildlife, livestock, and people; habitat for many species; and recreation opportunities. Consequently, springs have a considerable impact on regional biodiversity and support more than 1,200 rare species throughout the Southwest. Springs are also indicators of environmental change; although aquifers are remote and hidden underground, aquifer health can be conveniently measured by spring emergence. Though ecologically important, springs are among the most threatened types of ecosystems. They are subject to intensive groundwater extraction and climate change, which place springs in arid regions at high risk of degradation and loss. However, if the supporting aquifer is relatively intact, springs are resilient and managers are often able to restore them if they are aware of this opportunity.

Although they are critical resources, monitoring of springs in Arizona has been limited. This lack of information makes it uncertain as to how, in the context of climate change, improved land management practices like the 4FRI will affect thousands of forested springs in the project area and throughout the Southwest. The Springs Stewardship Institute (SSI) is a nonprofit organization whose mission is to improve knowledge and stewardship of springs through research and education. With administrative support from the Museum of Northern Arizona, SSI has participated in several springs monitoring projects throughout the Southwest, and has been monitoring responses of 56 4FRI springs since 2019 to ascertain how the forest treatments will affect aquifer recharge, spring flow, and habitat quality. Results of this study will improve knowledge of spring ecosystems and influence future management considerations.

Key Issues Addressed

Climate change-induced reduction of snowpack and increased evapotranspiration are predicted to reduce infiltration into aquifers and spring discharge. Arizona typically has a bimodal climate pattern, characterized by high amounts of precipitation in both winter and summer. However, recent precipitation data has shown two new patterns emerging, with some years having low winter precipitation and high summer precipitation, and others with low winter precipitation and no summer monsoons. Depending on the groundwater flow path and how long it resides within the aquifer, discharge from springs may lag behind such climate patterns, necessitating long-term study to understand the impacts of climate change on springs.

Springs integrate the many variables contributing to changing aquifer conditions, but the lack of monitoring data makes it difficult to accurately predict climate change impacts. In addition, factors such as aquifer hydrogeology can result in different individual spring responses to land use changes. Arizona has almost 11,000 springs, but only about 1,200 (a little over 10%) of them have been visited and assessed as ecosystems. Most northern Arizona springs are too small to monitor remotely, and field monitoring is challenging due to their remoteness, access constraints related to the fire season, and to the severity of winter conditions. Nonetheless, springs must be monitored to improve understanding of seasonality, perenniality, and responses to climate and land management changes to inform further stewardship strategies.

Project Goals

• Monitor how spring discharge and habitat quality have been affected by 4FRI prescribed burn prescribed burn
  A prescribed burn is the controlled use of fire to restore wildlife habitat, reduce wildfire risk, or achieve other habitat management goals. We have been using prescribed burn techniques to improve species habitat since the 1930s.
  
  Learn more about prescribed burn and mechanical thinning treatments
• Use monitoring results to inform future management of spring ecosystems
• Gather data about spring ecosystem variability and underlying features in northern Arizona 

Project Highlights

Preservation Through Isolation: The isolated nature of spring ecosystems often protects them from invasive species invasive species
An invasive species is any plant or animal that has spread or been introduced into a new area where they are, or could, cause harm to the environment, economy, or human, animal, or plant health. Their unwelcome presence can destroy ecosystems and cost millions of dollars.

Learn more about invasive species like bullfrogs because they do not share surface water with other water sources.

• Monitoring Process: This study is the most significant spring monitoring effort on the Colorado Plateau. The project team collected data on 56 selected springs on the landscape, including three different treatment areas during the spring and late summer of the past four years. Half of the springs were in 4FRI treatment areas and half outside the treatment areas. Similarly, spring sites were split equally between springs sourced from basalt and sedimentary aquifers. The project team selected forested hillslope and helocrene (wet meadow) spring types, and inventoried each spring in detail at the start of the project and will do so again at the end of the study to observe changes in habitat over time. Discharge and habitat area are being monitored annually, and a sensor in each spring provides continuous information on flow.
• Integrative Data Collection: The data collected in this project were not limited to hydrology. During the initial inventory, experts in hydrology, biology, zoology, and geography all visited each site for two hours to document the ecosystem status and collect habitat quality assessment data. These inventory data allowed researchers to identify patterns in springs’ discharge, habitat area, biodiversity, and hydrogeology. 
• Springs Online: The project team reported their data through the Springs Online database. This free database allows users to analyze variables (habitat area, discharge, etc.) within and among springs and quickly auto-generates a summary report of any spring, making consistent monitoring data of the 56 springs readily accessible to managers and interested groups. 
• 4FRI Treatment Effects: There have not yet been any clear results regarding hydrological changes caused by forest management due to delay in treatments, but it seems that burning may not produce the hypothesized effects. A site that was burned in a wildfire has not yet shown any change in discharge over time. However, it may take more than the five-year duration of this project for water table responses to occur. Thinning may be a more beneficial strategy, because fire may increase soil hydrophobicity, reducing infiltration. Thinning may also reduce shade and allow increased wetland plant development. 

Lessons Learned

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Delay of 4FRI treatment implementation meant researchers have not yet detected impacts on springs from the treatments; however, researchers have been able to learn about spring behavior and response to varying climate patterns. Winter precipitation, and associated snowmelt, is more influential on spring discharge than summer precipitation, which evaporates faster and reduces infiltration and spring discharge. Researchers report that years with no summer monsoons were detrimental to spring habitat, resulting in shrinking of habitat area.

Springs fed by limestone aquifers were more perennial than previously thought, even when they had small groundwater catchments (areas of land where surface water infiltrates). Limestone aquifers supported perennial spring flow and high-quality spring habitat that did not require additional management. Kaibab limestone is not known as an important aquifer in the Grand Canyon or Flagstaff regions, but it produced relatively perennial flow and high-quality spring habitat along the Mogollon Rim at the southern edge of the Colorado Plateau. In contrast, springs fed by basalt aquifers were often ephemeral and their habitats were more likely to be degraded and require additional management. 

Climate change is reducing winter precipitation, which is more likely to negatively impact ephemeral basalt aquifer-derived springs by reducing discharge. This is worrisome for ranchers who commonly use basalt-aquifer springs to water livestock. Additional water catchments like cattle tanks are likely to go dry during drought years, so improved management of springs may be a more reliable strategy. If the supporting aquifer is relatively intact, the ecological integrity of a spring ecosystem can be sustainably managed by fencing the source or by creating a stepping stone trail for access. However, this makes understanding aquifer integrity essential for management decision-making. 

Through this study, researchers learned best monitoring and management practices. Springs are highly individualistic ecosystems, each with their own suite of potential invertebrate indicator species. Thus, feeding guilds of aquatic invertebrates are likely better indicators of spring health than individual species. Additionally, SSI research indicates that thinning right up to the edge of the spring, instead of the current practice of leaving a buffer around it, will increase wetland vegetation productivity and diversity, and improve wildlife access.

Next Steps

• Compile the data gathered from the five-year study to develop habitat and climate assessments, models, and recommendations. 
• Compare study results with data collected from three long-term study sites in the Southwest to investigate patterns between climate and spring ecosystem habitat responses.

Funding Partner

United States Forest Service 

Resources

• Tobin, B.W., Springer, A. E., Kreamer, D. K., & Schenk, E. (2018). Review; the distribution, flow, and quality of Grand Canyon Springs, Arizona (USA). Hydrogeology journal, 26(3), 721–732. 
• Stevens, Larry (2023, March 21). Springs Monitoring for the Four Forest Restoration Initiative in Northern Arizona[Webinar]. Conservation and Adaptation Resources Toolbox.
• Springs Online: The Springs and Springs-Dependent Species Database
• 4FRI Springs Monitoring — Springs Stewardship Institute (springstewardshipinstitute.org)
• Coconino National Forest
• Abe Springer, College of the Environment, Forestry, and Natural Sciences, Northern Arizona University

Contact

Lawrence E. Stevens, Director, Springs Stewardship Institute: larry@springstewardship.org

Case Study Authors

• Kate Richter, CART Student Intern, University of Arizona
• Lawrence E. Stevens, Director, Springs Stewardship Institute

Suggested Citation

Richter, K. and Stevens, L.E. (2024). “Springs Ecosystems Monitoring for the Four Forest Restoration Initiative.” CART. Retrieved from https://www.fws.gov/project/spring-ecosystems-monitoring-4fri.