Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Groundwater dependence of riparian woodlands and the disrupting effect of anthropogenically altered streamflow

Rohde, Melissa M., Stella, John C., Roberts, Dar A. and Singer, Michael Bliss ORCID: https://orcid.org/0000-0002-6899-2224 2021. Groundwater dependence of riparian woodlands and the disrupting effect of anthropogenically altered streamflow. Proceedings of the National Academy of Sciences 118 (25) , e2026453118. 10.1073/pnas.2026453118

[thumbnail of Clean_Rohde_PNAS_GroundwaterDependence_submitted_revised_clean.pdf] PDF - Accepted Post-Print Version
Download (2MB)

Abstract

Riparian ecosystems fundamentally depend on groundwater, especially in dryland regions, yet their water requirements and sources are rarely considered in water resource management decisions. Until recently, technological limitations and data gaps have hindered assessment of groundwater influences on riparian ecosystem health at the spatial and temporal scales relevant to policy and management. Here, we analyze Sentinel-2–derived normalized difference vegetation index (NDVI; n = 5,335,472 observations), field-based groundwater elevation (n = 32,051 observations), and streamflow alteration data for riparian woodland communities (n = 22,153 polygons) over a 5-y period (2015 to 2020) across California. We find that riparian woodlands exhibit a stress response to deeper groundwater, as evidenced by concurrent declines in greenness represented by NDVI. Furthermore, we find greater seasonal coupling of canopy greenness to groundwater for vegetation along streams with natural flow regimes in comparison with anthropogenically altered streams, particularly in the most water-limited regions. These patterns suggest that many riparian woodlands in California are subsidized by water management practices. Riparian woodland communities rely on naturally variable groundwater and streamflow components to sustain key ecological processes, such as recruitment and succession. Altered flow regimes, which stabilize streamflow throughout the year and artificially enhance water supplies to riparian vegetation in the dry season, disrupt the seasonal cycles of abiotic drivers to which these Mediterranean forests are adapted. Consequently, our analysis suggests that many riparian ecosystems have become reliant on anthropogenically altered flow regimes, making them more vulnerable and less resilient to rapid hydrologic change, potentially leading to future riparian forest loss across increasingly stressed dryland regions.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Earth and Environmental Sciences
Water Research Institute (WATER)
Publisher: National Academy of Sciences
ISSN: 0027-8424
Date of First Compliant Deposit: 7 May 2021
Date of Acceptance: 29 April 2021
Last Modified: 17 Nov 2023 09:40
URI: https://orca.cardiff.ac.uk/id/eprint/140993

Citation Data

Cited 13 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item Edit Item

Downloads

Downloads per month over past year

View more statistics