The structure and functionality of communities and food webs in streams along the epigean–hypogean continuum: unifying ecological stoichiometry and metabolic theory of ecology

Subterranean streams represent unique heterotrophic ecosystems, usually supported by organic matter imported from the surface. Traditionally, biological communities subterranean were characterized as simple associations, with low diversity and species abundance, comprising mostly aquatic invertebrates connected few trophic links compared those of However, these features have not yet been described in wider context fluxes energy nutrients through food webs along a gradual switch autotrophy (dominated photosynthesis) towards heterotrophy detritus) following surface–subterranean continuum. Combining most recent predictions Ecological Stoichiometry Metabolic Theory Ecology, this article provides theoretical framework aiming to explain patterns observed continuum streams. It is predicted that main factors constraining structure functioning are decline quantity basal resources gradient, availability water affects quality. With increasing dissolved water, sinking-cave hypothesized fluctuate between being N and/ or P co-limited C-limited. Combined, quantity, quality, regulate bottom–up mechanisms, reflected decreased flux macronutrients webs. The consequences effects biomass, secondary production, consumption rate, mean body size communities, together potential increases elemental imbalance for macronutrients, omnivory, position, niche width overlap among consumers induce changes topology stream webs, which become shorter, lower at base network, but increased connectance environmental gradient.