Speaker: Dr. Tom Giambelluca
Replacement of native plants by non-native invasive species can affect water processes and impact water resources in several ways. Perhaps the most important effect of invasion is the possible increase in transpiration by fast-growing invasive plants, leading to a greater proportion of water input being lost to the atmosphere as evapotranspiration. Invasive plants in Hawai‘i are widely believed to use more water (i.e., to have higher transpiration rates) than the native plants they replace. If true, this would mean that the widespread invasion of Hawai‘i’s ecosystems by non-native plants is having a big negative impact on our water resources by reducing streamflow and groundwater recharge. However, the research to demonstrate the effect of invasion on evapotranspiration is still relatively limited. In this presentation, I will discuss the reasons why invasive plants might be big water users and show the results of our field observations of transpiration and total evaporative water loss in native- and non-native-dominated ecosystems.