Climate impacts
Boreal canopy lichens declined from several drivers
Open access · cc by · source: Europe PMC
Over a decade of Swedish forest inventory, hair lichens Alectoria, Usnea, and Bryoria became less common, with losses tied to forestry, nitrogen, and climate together—not one driver alone.
Key findings
National occurrence fell for all three genera (Alectoria relative loss ~1.70%/year). More than half of Alectoria records were lost in region 3. Drivers interacted: logging cycles, N sensitivity, and warming/rain all mattered, and traits such as color and dispersal shaped which genus declined where.
Methodology
Authors used Swedish NFI plots measured 10 years apart (1993–2002 vs 2003–2012) to track occurrence and thallus length of three filamentous canopy lichens on spruce, then related changes to forestry, N deposition, and climate variables.
Limitations
NFI presence on host trees does not measure biomass in the upper canopy or prove which single driver would reverse the trend if managed alone.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
NICHD Scandinavian SGA-study pairs found 55 of 412 children (12%) overweight or obese at age 5. Increasing maternal PFAS associated with higher BMI and triceps z-scores and with overweight, but associations differed by country and concentration; organochlorines were less consistent. Swedish NFI lichen occurrence, modeled 10 years apart, fell for three genera (Alectoria relative loss ~1.70%/year; more than half of Alectoria records lost in region 3) — presence/absence change, not human disease odds.
Evidence for the claim as stated.
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