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

Abstract

Subterranean streams represent unique heterotrophic ecosystems, usually supported by organic matter imported from the surface. Traditionally, the biological communities from subterranean streams were characterised as simple associations, with low diversity and species abundance, comprising mostly aquatic invertebrates connected by few trophic links compared with those of the surface. However, these features have not yet been described in the wider context of fluxes of energy and nutrients through food webs along a gradual switch from autotrophy (dominated by photosynthesis) towards heterotrophy (dominated by detritus) following the surface-subterranean continuum. Combining the most recent predictions of Ecological Stoichiometry and the Metabolic Theory of Ecology, this article provides a theoretical framework aiming to explain the patterns observed along the surface-subterranean continuum in streams. It is predicted that the main factors constraining the structure and functioning of communities and food webs are the decline in the quantity and diversity of basal resources along this gradient, along with nutrients availability in water that affects food quality. With increasing availability of dissolved nutrients in water, sinking-cave streams are hypothesised to fluctuate between being N and/ or P co-limited to C-limited.

Ecological stoichiometric characteristics of three dominant fish species from the Beibu Gulf: inter- and intraspecific variations

“…The current applications of ecological stoichiometry are mainly focused on environmental assessment (Nie et al, 2012;Wang et al, 2022), forest succession and recession (Wardle et al, 2004;Liu et al, 2022), consumer-driven nutrient cycles (Elser and Urabe, 1999), population dynamics (Andersen et al, 2004), nutrient dynamics (Sterner and Hessen, 1994;Czamanski et al, 2011), nutrient supply and demand balance (Schade et al, 2005), nutrient limitation and carbon cycling (Nessel et al, 2021;Fernández-Martínez, 2022;Filipiak and Filipiak, 2022), food webs (Glibert et al, 2011;Pacioglu et al, 2021), biogeochemical niches (González et al, 2017;Peñuelas et al, 2019;Sardans et al, 2021), biological invasions (González et al, 2010), and biological evolution (Sardans et al, 2012;Jeyasingh et al, 2014). Ecological stoichiometry theory has become an effective tool and provided new ideas for studying consumer stoichiometry, nutrient cycles, and biogeochemical cycles.…”