Multi-species population dynamics

 This is a multi-species version of the classic Lotka-Volterra competition model. The dynamics of each species is given by:

dB_i/dt = r_i*(1-sum_{j = 1,nsp}(c_i,j*B_j))

where:
B_i is the biomas of species i;
r_i is the maximum specific growth rate for species i;