A new nestedness estimator in community networks

A recent problem in community ecology lies in defining structures behind matrices of species interactions. The interest in this area is to quantify the nestedness degree of the matrix after its maximal packing. In this work we evaluate nestedness using the sum of all distances of the occupied sites to the vertex of the matrix. We calculate the distance for two artificial matrices with the same size and occupancy: a random matrix and a perfect nested one. Using these two benchmarks we develop a nestedness estimator. The estimator is applied to a set of 23 real networks of insect-plant interactions.