Managing salmon for wildlife typically focuses on providing enough biomass, a measurement of the total kilograms of spawning salmon available. We asked whether biomass-and the number of salmon species-might affect salmon consumption by black bears in coastal BC, a measure that strongly relates to population productivity and health.
Biomass actually did not matter to salmon consumption, at least in the relatively productive watersheds we sampled.
However, diversity had a large and positive effect.
We found that when black bears have access to four salmon species, they consume ~3x more salmon each year (Figure A)… than they do when there is one big run of equal biomass comprised of only one salmon species (Figure B).
Should managers want to maintain opportunities for bears to eat high levels of salmon, preserving the diversity of species present in watersheds will be key.
This requires safeguarding smaller, less commercially important salmon species, often neglected in salmon management.
Service C. N., Bateman, A. W., Adams, M. S., Artelle, K. A., Reimchen, T. E., Paquet, P. C. & Darimont, C. T. (2018). Salmonid species diversity predicts salmon consumption by terrestrial wildlife.Journal of Animal Ecology. 2018;00:1–14. https://doi.org/10.1111/1365-2656.12932