For Europe’s salamander fungus, diversity and density are telling different stories
WHAT THE EVIDENCE SAYS
A multi-site synthesis assembled 2,625 amphibians from Bsal-positive locations spanning 14 species. Across infected communities, Bsal prevalence was negatively associated with host-species richness and positively associated with total amphibian abundance. In fire salamanders alone, abundance instead tracked lower prevalence, a pattern the authors interpret cautiously because disease-caused mortality can itself lower host density.
WHY IT MATTERS / OUR READ
Disease ecology can invert the meaning of a familiar metric. Richness may be associated with lower pathogen prevalence, but abundance can be both a driver and a consequence of disease; management should avoid translating a cross-site 'dilution' pattern into a simple diversity prescription without resolving mechanism.
CAVEATS / UNCERTAINTY
The analysis compiles heterogeneous observational datasets and is dominated by German sites. The fire-salamander richness-by-density interaction was not statistically significant, and infected-site sampling, life stage and mortality can bias apparent prevalence relationships. This does not demonstrate a diversity intervention that controls Bsal.
SOURCE
Journal of Applied Ecology
View original evidence ↗
Across Bsal-positive European sites, infection prevalence fell as amphibian richness rose, while fire salamanders showed a reversed density relationship consistent with disease-driven population loss.
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