Colonization of decomposing deciduous leaf litter by Testacea (Protozoa, Rhizopoda): Species succession, abundance, and biomass.

The colonization of leaf litter by testate amoebae in a cool temperate deciduous forest was studied over the first 60 months of decomposition. No colonization of fresh leaf litter by Testacea was recorded before the first spring thaw period. Colonization of aspen and balsam leaves was similar in terms of species and numbers of species, with the balsam litter being colonized by slightly fewer species. In the aspen litter bags, all the L-layer species were present after 18 months, and all the species recorded in all soil layers were found after 60 months. The proportion of species which constructed their tests from platelets rather than sediment was 70% of the total number of species for the first 36 months of colonization of both litter types. After 60 months, seven species comprised 70% of the total numbers of Testacea but only 33-38% of the total biomass. Significant, positive correlation existed between the dry weight loss of leaf litter and the total number of active Testacea, the total number of living Testacea, and the total number of species present. The prime limitations to testacean colonization of decomposing leaf litter appeared to be substrate quality, food supply and/or availability of test-building materials.