H2fun {bipartite} | R Documentation |
Calculates the overall level of specialisation of all partners in a bipartite web.
H2fun(web)
web |
A matrix representing the interactions observed between higher trophic level species (columns) and lower trophic level species (rows). Usually this will be number of pollinators on each species of plants or number of parasitoids on each species of prey. |
H2' is an index describing the level of specialisation, or should one say: selectiveness, of an entire bipartite network (Blüthgen et al. 2006). It describes to which extent observed interactions deviate from those that would be expected given the species marginal sums. The more selective a species, the larger is H2' for the web.
H2' is an extension of d' (see dfun
) for the entire network. Check
there for details on finding maximum and minimum H2 values for a given web.
For internet implementation see also: http://nils.mib.man.ac.uk/~nils/stat/
H2 |
The H2'-value for the web matrix. |
H2min |
Heuristic minimum H2-value for the web matrix. |
H2max |
Heuristic maximum H2-value for the web matrix. |
H2uncorr |
Uncorrected H2-values (before ranging between min and max), rounded to three digits. |
Carsten F. Dormann and Jochen Fründ
Blüthgen, N., Menzel, F. and Blüthgen, N. (2006) Measuring specialization in species interaction networks. BMC Ecology 6, 9
dfun
doing the same for each species in the web matrix.
data(Safariland) H2fun(Safariland)