  The structure of ecological networks, in particular food webs, determines
their ability to evolve further, i.e. evolvability. The knowledge about how
food web evolvability is determined by the structures of diverse ecological
networks can guide human interventions purposefully to either promote or limit
evolvability of ecosystems. However, the focus of prior food web studies was on
stability and robustness; little is known regarding the impact of ecological
network structures on their evolvability. To correlate ecosystem structure and
evolvability, we adopt the NK model originally from evolutionary biology to
generate and assess the ruggedness of fitness landscapes of a wide spectrum of
model food webs with gradual variation in the amount of feeding loops and link
density. The variation in network structures is controlled by linkage rewiring.
Our results show that more feeding loops and lower trophic link density, i.e.
higher autonomy of species, of food webs increase the potential for the
ecosystem to generate heritable variations with improved fitness. Our findings
allow the prediction of the evolvability of actual food webs according to their
network structures, and provide guidance to enhancing or controlling the
evolvability of specific ecosystems.
