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#connectance

3 public questions tagged with this topic.

Connectance in food web is calculated by:

Food-web connectance is the fraction of possible feeding links that are actually realized, calculated as actual links divided by potential links. If directed links among S species are allowed, potential links may be S², S(S−1), or another denominator depending on whether cannibalism and basal species are included. Because conventions differ, comparisons require the same definition and sampling effort. Connectance influences possible pathways for energy flow and indirect effects, but observed values can decline artificially as more poorly resolved species are added. Energy budgets must distingu

Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 3

Connectance indicates:

“Lower complexity with richness” for connectance indicates. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Rates depend on temperature, moisture, substrate quality, consumer physiology, and the elemental balance between organisms and their food. These controls explain why the same process can differ among terrestrial, freshwater, and marine systems without changing its definition. The remaining alternatives—“Higher complexity with higher richness”, “No relation”, “Random variation”—refer to diffe

Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 17-19

Connectance tends to:

Food-web connectance is the proportion of realised feeding links among all possible links. As species richness increases, the number of possible pairwise interactions rises approximately with the square of species number, whereas each consumer usually interacts with only a limited subset. Consequently connectance often decreases with richness even if the absolute number of links increases. The pattern depends on sampling and web definition, so it is an empirical tendency rather than an inviolable law. Mechanistic interpretation connects individual physiology and species interactions to populat

Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 17-19