A new study predicting the environmental effects of climate change, urban development, and land cover was recently published in Water Resources Research. The authors—representing diverse research specialties, including members from WRRC—concluded that the effects will increase habitat suitability of the invasive seaweed Hypnea musciformis and decrease the growth of the culturally-important native limu Ulva lactuca (or limu pālahalaha). With the support and input from community and agency partners, three future climate and management scenarios were developed to highlight the important stressors Hawai‘i’s hydrologic system faces. These scenarios were applied to an integrated land-sea model of the Keauhou basal aquifer (Kona, Hawai‘i Island) to predict how groundwater quantity and quality will change under different assumptions. The model results were then combined with lab experiments to quantitatively estimate how the scenario assumptions will impact the growth of the seaweed species. The findings from this study emphasize how watershed management actions are linked to the health of groundwater dependent ecosystems.
Photo caption: Limu pālahalaha, Ulva sp., an abundant and ecologically and culturally valued native limu in Kona, Hawaiʻi. (Photo credit: Leah Bremer)
Journal Paper: Okuhata, B.K., Delevaux, J.M.S., Richards Donà, A., Smith, C.M., Gibson, V.L., Dulai, H., El-Kadi, A.I., Stamoulis, K., Burnett, K.M., Wada, C.A., Bremer, L.L. (2023). Effects of multiple drivers of environmental change on native and invasive macroalgae in nearshore groundwater dependent ecosystems. Water Resources Research, 59(7), e2023WR034593. https://doi.org/10.1029/2023WR034593