A modified niche model for generating food webs with stage-structured
consumers: The stabilizing effects of life-history stages on complex
food webs
Abstract
1. Almost all organisms grow in size during their lifetime and switch
diets, trophic positions, and interacting partners as they grow. Such
ontogenetic development introduces life-history stages and flows of
biomass between the stages through growth and reproduction. However,
current research on complex food webs rarely considers life-history
stages. The few previously proposed methods do not take full advantage
of the existing food web structural models that can produce realistic
food web topologies. 2. We extended the niche model by Williams &
Martinez (2000) to generate food webs that included trophic species with
a life-history stage structure. Our method aggregated trophic species
based on niche overlap to form a life-history structured population;
therefore, it largely preserved the topological structure of food webs
generated by the niche model. We applied the theory of allometric
predator-prey body mass ratio and parameterized an allometric
bioenergetic model augmented with biomass flow between stages via growth
and reproduction to study the effects of a stage structure on the
stability of food webs. 3. When life-history stages were linked via
growth and reproduction, fewer food webs persisted while persisting food
webs tended to retain more trophic species. Topological differences
between persisting linked and unlinked food webs were small to modest.
Temporal variability of biomass dynamics and slopes of biomass spectra
were lower in the linked food webs than the unlinked ones, suggesting
that a life-history stage structure enhanced stability of complex food
webs. 4. Our results suggest a positive relationship between the
complexity and stability of complex food webs. A life-history stage
structure in food webs may play important roles in dynamics of and
diversity in food webs.