Fish need water. While minimum flows and other emergency-response approaches might save some fishes during crises, such “bucket-based” approaches are insufficient in the long-term. For example, biologists in the Owens Valley saved the Owens pupfish from extinction by translocating individuals via buckets; however, the underlying cause of this dire circumstance—low dissolved oxygen related to insufficient flow and limited understanding of habitat needs—remains a persistent challenge.  Understanding the needs of species forms a better basis for sustaining native fish. But developing this knowledge takes time and resources.

Despite decades of research, we have an insufficient understanding of flow needs for many native freshwater species in California. How much water is needed during summer to support resident native species, such as sculpin or pikeminnow? Or, how large must spring flows be to trigger Sacramento splittail spawning? Most knowledge of suitable flows is limited to salmonids or species listed under the US Endangered Species Act (for example, see Michel et al. 2021).

In terrestrial systems, the umbrella species approach is widely used to address management challenges where habitat needs of species are unknown, too costly or resource-intensive to assess. This approach seeks to protect habitat and life history needs of one or a few species (the “umbrellas”), expecting these efforts will confer protection to other species in the same area. For example, the Northern Spotted Owl has been used as an umbrella species, as it resides in old-growth forests, which also provides habitat to numerous co-occurring species.

What makes a suitable umbrella species?

Previous conservation efforts have selected umbrella species due to their legal listing under state or federal endangered species acts. Others have used a set of criteria, including spatial requirements, the role a species plays in the ecosystem or community it lives, and vulnerability of a species to decline or extirpation. Some conservation efforts rely on expert opinion. In most cases though, the umbrella species concept has been applied only in terrestrial systems and species have not always been selected using quantitative and defensible criteria.

In a recent study, we established an approach for selecting suites of freshwater umbrella fish species across California. We used information such as species ranges, life history traits, and climate change vulnerability scores to identify suites of umbrella fish species. In addition to these criteria, we used expert knowledge of nine ichthyologists from California to help develop our method and validate datasets and results.

How did we do this and what questions did we ask?

Continue reading the article from California WaterBlog here.