PARENT SESSION
Poster Session #61: Soil Ecology II.
Thursday, August 8. Presentation from 8:00 AM to 9:30 AM. Exhibit Hall B & C, TCC

Succession and recolonization trends by protozoa in litter decomposition between sites.

ADL, Sina^*,1,2, Coleman, David¹, ¹ University of Georgia, Athens, GA² Dalhousie University, Halifax, Nova Scotia, Canada

ABSTRACT- We set out to determine whether it was feasible to describe Protozoa succession trends in litter decomposition and disturbed soil recolonization. Leaf litter bags representing slow, medium and fast mass-loss rates were set out in a tropical and temperate forest, in both riparian and terrestrial areas. Disturbed soil consisted of a matrix of 60-cm dug holes with and without litter amendment, replicated at grass field, riparian and terrestrial sites. All these plots were monitored every 2-3 months for over one year. Protozoa, nematodes and microarthropods were enumerated into families and functional groups, and litter C:N was obtained. In the leaf litter, there was more seasonal influence on species composition in the temperate than in the tropical sites. The Protozoa functional groups between litter species were similar for a decomposition stage (determined by mass loss). The plots with disturbed soil required 2-5 months to accumulate all functional groups. The litter amended plots recovered only slightly faster, although species abundances were higher in the early stages. However, the communities in these plots remained different from the surrounding soil, and simpler, after more than one year despite the small plot sizes. There was faster recovery in the forest than in the grassy field. The results show that our time frame was adequate and that it is possible to observe succession trends for soil Protozoa. This approach provides some indication of which are early colonizers and which appear in more complex soil community structure and food webs. The implications of these results to remediation efforts would suggest that active species reintroduction is required, because immigration over distances is slow. For instance in eroded, human impacted or damaged soils. Furthermore, functional groups need to be reintroduced at the correct successional stage if they are to be successfully reintroduced.

KEY WORDS: succession, Protozoa, microarthropods, decompositiion