Moose Herbivory in Taiga: Effects on Biogeochemistry and Vegetation Dynamics in Primary Succession

Abstract

Early successional processes in taiga forest ecosystems are believed to be primarily under abiotic controls. with biotic factors taking on greater importance later in the successional sequence. Here we report how moose (Alces alces L.), a dominant mammalian herbivore, exert major control over biogeochemical processes early in succession in the taiga of Alaska. Moose browsing affects soil chemistry and vegetation dynamics in ways that influence subsequent plant establishment and ultimately forest development. Browsing significantly changed soil organic matter pools, the composition of soil carbon fractions. and the stable isotope signature (δ 13 C and δ 15 N) of surface soils. These edaphic modifications were accompanied by changes in plant species composition that accelerate the successional trajectory. Thus, we contend that the rate of initial plant establishment and early forest succession in taiga is under significant control by mammalian herbivores.