Here's the quick version of what we found:
- Streams which are downstream of areas where more of the land is dedicated to human activity tend to have fewer unique species.
- At a larger geographic scale, in our case a regional watershed, higher upstream land use was also associated with each local stream community becoming less similar to one another in terms of the species present. This could be called an Anna Karenina principle: every community declines in its own unique way.
- Using zeta diversity, a more general framework for assessing changes in diversity across multiple communities, we were able to construct a well-correlated proxy for the California Stream Condition Index, a measure of stream community health.
Any questions on our research? Please contact me at firstname.lastname@example.org