alphaterm.RdFrom a competition matrix (for the moment the distance between species traits) and a vector of abundances by species, return the alpha term in the Beverton-Holt equation. The order of species between the two should be the same as no checks are done. Typically the competition matrix is an euclidean trait distance matrix between species. The closer the species are the higher the combination. The term is computed as follow:
alphaterm(distance, Nts, A, B, di_thresh)dissimilarity matrix between species
vector of abundances of species at time t
scalar for the inter-specific competition
scalar for the intra-specific competition
dissimilary threshold above which species are considered maximally dissimilar
$$ \alpha_i = \sum_{j = 1, j \neq i}^{S} N_{t, j, x} \times (1 - \delta_{ij}) $$, where alpha_i is the competition term of species i; Ntjx the abundance of species j, at time t, in patch x and delta_ij the functional distance between species i and species j.