Bongers, A.M.T.

Ferris, H.

Goede, R.G.M., de

Wageningen Yield 

Symposium abstracts
078 Nematode faunal analyses to assess food web enrichment and connectance
Howard FERRIS1,∗, Tom BONGERS 2 and
Ron DEGOEDE 3
1Department of Nematology, University of California, Davis, CA 95616, USA
2 Laboratory of Nematology, Wageningen University, P.O. Box 8123, 6700 ES Wageningen, The Netherlands
3 Sub-department of Soil Quality, Wageningen University, P.O. Box 8055, 6700 EC Wageningen, The Netherlands
∗hferris@ucdavis.edu.
The cp classification recognises that nematode taxa
with anatomical and physiological commonalities are
probably similarly adapted to specific environmental con-
ditions. Functional guild analysis, which integrates cp-
scaling with food sources, reveals that some guilds re-
spond opportunistically to enrichment while others rep-
resent the presence of higher trophic connectance in the
food web. This dichotomy was portrayed graphically in cp
triangles as the proportional representation of enrichment
opportunists (cp 1), general opportunists (cp 2) and taxa
indicating higher connectance (cp 3-5). Confounded in the
calculation of cp triangles is interdependence of the axes;
proportionality of the three groupings to the whole nema-
tode fauna requires that increase in food web structure (cp
3-5 taxa) concomitantly decreases the enrichment indica-
tor (cp 1 taxa). The categorical separation of nematode
taxa into five cp classes does not imply unit increments in
r or K characteristics. We use body size and growth rates
to weight the importance of enrichment indicators and es-
timates of corresponding food web connectance to weight
the importance of structure indicators. We consider cp 2
taxa basal to both trajectories and calculate position along
the enrichment and structure axes of a faunal diagram in-
dependently as the weighted ratios of the indicator and
basal taxa.


Nematode faunal analyses to assess food web enrichment and connectance

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