A recent study published in Nature Water has explored the relationship between groundwater levels and ecosystems in California. The research, spanning 38 years of satellite data, was conducted by a team led by the SUNY College of Environmental Science and Forestry (ESF) with partners from University of California Santa Barbara (UCSB), Cardiff University, and Desert Research Institute (DRI). This study aims to inform water management practices that consider both human and ecosystem needs.
Christine Albano, Ph.D., from DRI, co-authored the study. She highlighted the importance of understanding water requirements for groundwater-dependent ecosystems to develop effective water management strategies. "Understanding how much water is needed to sustain groundwater dependent ecosystems is critical for developing strategies that can meet a wide variety of water management objectives," Albano stated.
The research identifies thresholds of groundwater depth necessary to support sensitive ecosystems under California's Sustainable Groundwater Management Act framework. Dr. Melissa Rohde led the study as part of her doctoral research at ESF. She emphasized the global significance of managing groundwater sustainably: “A vast majority of our planet’s freshwater is groundwater, but we don’t acknowledge or manage it sustainably, resulting in serious consequences for humans and natural ecosystems.”
The study utilized Landsat satellite images from 1985 to 2022 along with statewide groundwater well data to assess impacts on plant communities. The team developed standardized metrics applicable across diverse ecosystems to determine ecological thresholds.
Dr. John Stella from ESF noted the importance of these ecosystems for biodiversity: “Groundwater-dependent ecosystems such as wetlands, floodplains, and riparian zones have a very outsized importance on biodiversity." He explained their approach using large datasets to identify conservation targets.
The research also evaluated responses to climate events like California's drought from 2012-2016. It found that vegetation maintaining connection with groundwater during droughts can serve as refugia for species like riparian birds or fish.
Dr. Dar Roberts from UCSB remarked on the significance of this extensive study: “This type of study...shows the promise for similar studies over a much larger geographic area using the approach pioneered by Dr. Rohde.”
Albano further explained how root depth informs ecosystem health: “We found that vegetation was healthier where groundwater levels were within about 1 meter of maximum root depth.” The findings aim to guide future water management decisions both in California and globally.