Effects of bark accumulation on benthic infauna at a log transfer facility in southeast Alaska

Abstract

Effects of bark accumulation are examined by comparing macro-infauna (numbers and biomass) at a log transfer facility with those of an adjacent unaffected region. The quantities of some infaunal species (and groups of species) are significantly different in ‘shallow’ vs ‘deep’ water zones, arbitrarily defined as 3–6 and 7–10 m below mean lower low water (MLLW), respectively. Bivalves and polychaetes dominate the fauna of both areas, but are significantly diminished under bark deposits. Results indicate that a complete covering of bark debris can have drastic effects on the structure of benthic communities. In extreme conditions macro-infauna can be virtually eliminated, in less severe instances, deposit feeders replace suspension feeders.