Studying the Influence of Streamflow Variability on Fish Populations to Understand Nutrient Transport in Hawaiian and Alaskan Streams in a Changing Climate

Ecosystems spanning the zones from “ridge-to-reef" and “icefield-to-ocean” are home to relatively high levels of biodiversity; serve as conduits of nutrients to sensitive coastal environments; and are culturally and economically important to local communities. These systems are smaller and have unique geological and streamflow properties compared to more typical river systems and, because of this, it is not clear how they will respond to shifting climatic patterns.  

Both Hawaiian ridge-to-reef and Alaskan icefield-to-ocean ecosystems face the potential of climate-driven changes in extreme flow events, such as floods and droughts, that could dramatically change how critical nutrients are retained and transported. The overall goal of this project is to develop a multidisciplinary team to evaluate the effect of streamflow changes in ridge-to-reef and icefield-to-ocean watersheds. First, the researchers will evaluate the effects of annual variability in streamflow conditions on the growth and recruitment of invasive armored suckermouth catfish in Hawaiian streams, which can lead to a disruption of nutrients in the local ecosystem. Second, these findings will be compared to those of a complementary study linking streamflow changes to freshwater salmon growth in southeast Alaska. This joint effort leverages existing work to further investigate the effect of streamflow patterns on fish populations. The expected products from the project include a streamflow pattern dataset for Makiki, Mānoa, and Pālolo streams, a dataset describing armored suckermouth catfish populations in these streams, as well as written publications describing their findings.  .  

Resource managers working in ridge-to-reef and icefield-to-ocean systems need streamflow-ecology information to guide decisions related to habitat restoration, streamflow management, invasive species control, and fisheries. To meet this need, the collaborative and multidisciplinary effort of this project will establish a path toward better understanding the changes of stream habitats in these watersheds and co-produce potential strategies to inform adaptive management.