Data from: Enigmatic freshwater mussel declines could be explained by the biodiversity-disease relationship

The biodiversity-disease relationship states that increased species
richness leads to lower pathogen pressure (i.e., the dilution effect), an
effect that erodes with biodiversity loss. However, whether losses of the
dilution effect can trigger extinction cascades remains largely
unexplored. To explore this idea, we consider declines in freshwater
mussels, on average the most threatened non-marine group of organisms in
the world. We argue that anthropogenically-stimulated declines in mussel
richness amplify pathogens in remaining species. Pathogen amplification
triggers further local losses in both mussel abundance and richness,
explaining the observed so-called “enigmatic” declines in freshwater
mussels.  Vulnerable communities could become trapped in cycles
of pathogen amplification and host decline. We highlight knowledge gaps
and provide key steps to assess the likelihood of this occurring; these
key steps are applicable to any host group.  Policy implications.
Our argument constitutes a testable hypothesis that may explain richness
or abundance declines in previously intact communities. We provide further
impetus for the consideration and preservation of diversity at a local
scale, and show that effective conservation requires integration of both
host and parasite ecology.