Quintanilla, M., G. Bird, and G.P. Robertson
Presented at the All Scientist and GLBRC Sustainability Meeting (2009-05-05 to 2009-05-07 )
Soil is a largely unexplored natural resource and nematodes can be used to provide a view into its processes and conditions. Nematodes and nematode community structure analysis have been shown to be useful indicators in ecological studies of the impact of management on soil quality. In this research deciduous forest, old field succession, no-till, bio-based (organic), and conventionally tillage ecosystems were compared using nematode community structure methodology. The study was conducted at the Long-Term Ecological Research (LTER) site at the Kellogg Biological Station (KBS), which is uniquely designed to evaluate alternative ecosystems. The objectives of the dissertation research were to: 1) compare soil nematode community structures among three agricultural managements systems at KBS/LTER (no-till, bio-based and conventional tillage), a natural forest and two field successions (grasses and forbs); 2) determine if the community indices which measure ecosystem biodiversity, stability and maturity can be used to distinguish among these ecosystems in relation to the level of soil disturbance and 3) record the document the nematode diversity at the different ecosystems at KBS/LTER. At KBS/LTER, nematode community structure indicated that the forest and old field successions were the most biodiverse, mature and stable ecosystems. The nematode communities were different from those associated with the agriculture soils. The conventional till or the no-till agricultural managements tended to have lowest biodiversity, maturity and evenness. Ecosystem specific taxa were observed. Soil moisture apparently played a role in the results. The results were clearest when the soil was dry. We believe that the increase of soil moisture made resources more available and that the opportunistic nematodes (r-strategist, or lower c-p values) more abundant and that this confused the results. Deciduous forests and mid-succession ecosystems were additionally associated with high organic soil carbon, low pH, and lower bulk density. The nematodes recovered from KBS/LTER ecosystem were recorded and photographic images were taken of most taxa recovered which can be seen at www.nemasoil.com.
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