  We study the dynamics of the generalized Lotka-Volterra model with a network
structure. Performing a high connectivity expansion for graphs, we write down a
mean-field dynamical theory that incorporates degree heterogeneity. This allows
us to describe the fixed points of the model in terms of a few simple order
parameters. We extend the analysis even for diverging abundances, using a
mapping to the replicator model. With this we present a unified approach for
both cooperative and competitive systems that display complementary behaviors.
In particular we show the central role of an order parameter called the
critical degree, $g_c$. In the competitive regime $g_c$ serves to distinguish
high degree nodes that are more likely to go extinct, while in the cooperative
regime it has the reverse role, it will determine the low degree nodes that
tend to go relatively extinct.
