Arid streams in a rainfall gradient produced more secondary biomass than wetter ones
WHAT THE EVIDENCE SAYS
Across nine rivers over three years, researchers compared invertebrate and vertebrate secondary production. Wetter streams had food-web energy concentrated in detritivorous invertebrates; arid streams showed more vertebrate herbivory and approximately twice the secondary production and biomass turnover.
WHY IT MATTERS / OUR READ
A changing rainfall regime can reorganize an aquatic food web even when the river still appears to flow; production depends on which trophic pathways carry energy.
CAVEATS / UNCERTAINTY
Site contrasts along a rainfall gradient are not a controlled climate-change experiment; geology, productivity and local biota may also differ. Reported production ratios are context-bound.
SOURCE
Ecology — primary comparative multi-river study
View original evidence ↗
Nine rivers tracked for three years shifted from detritivore-heavy food webs in wetter settings toward vertebrate herbivory in drier settings.
Read the Wild Lands assessment →