Leaf litter colonization by invertebrates in the littoral zone of a small oligotrophic lake

The colonization of deciduous leaf litter by aquatic invertebrates was stud ied at Scott Lake in Algonquin Park, Ontario, Canada. Deciduous leaf packs were colonized after only 2 days submergence. The invertebrate community wa s dominated by chironomids (25-94% depending on sampling period), and to a lesser extent by oligochaetes, turbellarians, and mayflies. Collectors, suc h as the chironomids Dicrotendipes, Pseudochironomus, Paratanytarsus and Pa rakiefferiella were the dominant functional-feeding group suggesting that l eaf litter is being used as habitat rather than a direct food source. Decid uous leaf litter lost a substantial amount of weight, due to leaching, afte r only 48 h submergence. Fall-shed beech (Fagus grandifolia) leaves decompo sed more rapidly than fall-shed sugar maple (Acer saccharum) leaves with da ily processing coefficients (k), determined using an exponential decay mode l, of 0.0058 and 0.0039, respectively. Conversely, conditioned maple leaves , defined as leaves remaining on the ground over winter, were processed fas ter than conditioned beech leaves, with coefficients of 0.0042 and 0.0014, respectively. It is speculated that inhibitory compounds have been leached from the maple leaves, allowing for faster leaf processing.