Insect Diversity Legon · Disturbance gradient
Findings

Richness is the least interesting number

All three sites carry a similar count of taxa. The differences appear when you ask which taxa: how many are found at one site only, how much the assemblages overlap, and which orders take over as the ground opens up.

One

Taxa recorded per site

Site I
21
Site II
26
Site III
27
Two

Taxa found at one site only

A taxon recorded at a single point is the clearest signal a site gives: it is either specialised to the conditions there, or it cannot persist elsewhere on the gradient.

Site I
15
exclusive to this site

71% of the 21 taxa recorded here were not found at either of the other two points.

Site II
21
exclusive to this site

81% of the 26 taxa recorded here were not found at either of the other two points.

Site III
22
exclusive to this site

81% of the 27 taxa recorded here were not found at either of the other two points.

Three

How much the sites share

Overlap is given as a Jaccard index — shared taxa divided by the combined list of both sites. A value of 1 would mean identical assemblages; 0 would mean no taxon in common.

Site I Site II
4 taxa in common
0.09
Site I Site III
4 taxa in common
0.09
Site II Site III
3 taxa in common
0.06
All three sites
2 taxa recorded everywhere
3%

Low overlap between the reference woodland and the roadside margin, with the managed grounds sitting between them, is the pattern a disturbance gradient predicts: the middle site borrows from both ends while each end keeps a set of taxa the other does not.

Four

Which orders dominate where

Read across the three columns rather than down any one of them. Ground-associated and litter-dependent groups thin out as cover is removed, while highly mobile flies and open-ground grasshoppers hold their position or gain it. Browse the records →