Input for most analyses is an interaction matrix of m higher level species with n lower level species, i.e. an n x m matrix, where higher trophic level species are in columns, lower level in rows. Column and row names can be provided. This is fundamentally different from multi-dimensional webs, which are organised as k x k matrix, i.e. each species against each other. Such a format is incompatible with the functions we provide here.
The first step is to visualise the interaction web. Two functions are on offer here: one (visweb) simply plots the matrix in colours depicting the strength of an interaction and options for re-arranging columns and rows (e.g. to identify compartments or nesting). The other function (plotweb) plots the actual web with participants (as two rows of rectangles) connected by lines (proportional to interaction strength).
The second step is to calculate various indices describing network topography. There are two different levels this can be achieved at: the entire web (using function networklevel) or the individual species (using function specieslevel). All other functions in the package are helpers, although some can be called on their own and return the respective result (dfun, H2fun and second.extinct with slope.bipartite).
See function description for details and examples.
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data(Safariland)
plotweb(Safariland)
visweb(Safariland)
networklevel(Safariland)
specieslevel(Safariland)Run the code above in your browser using DataLab