A unified framework for herbivore-to-producer biomass ratio reveals the relative influence of four ecological factors

Abstract

The biomass ratio of herbivores to primary producers reflects the structure of a community. Four primary factors have been proposed to affect this ratio, including production rate, defense traits and nutrient contents of producers, and predation by carnivores. However, identifying the joint effects of these factors across natural communities has been elusive, in part because of the lack of a framework for examining their effects simultaneously. Here, we develop a framework based on Lotka–Volterra equations for examining the effects of these factors on the biomass ratio. We then utilize it to test if these factors simultaneously affect the biomass ratio of freshwater plankton communities. We found that all four factors contributed significantly to the biomass ratio, with carnivore abundance having the greatest effect, followed by producer stoichiometric nutrient content. Thus, the present framework should be useful for examining the multiple factors shaping various types of communities, both aquatic and terrestrial.

Abiotic–Biotic Interrelations in the Context of Stabilized Ecological Potential of Post-Mining Waters

“…If fish accumulate nutrients from zooplankton in their bodies, they may be treated as nitrogen, phosphorus, and carbon sinks in the water column zone [55]. According to Kazama et al [56], the herbivores to primary producers' biomass relations reflect the structure of the aquatic community. Furthermore, multiple factors affect these relations, especially the production rate, defense traits, nutrients, and predation.…”

Size-dependent susceptibility of lake phytoplankton to light stress: an implication for succession of large green algae in a deep oligotrophic lake

“…Also, multi-year observations should be helpful to understand the effects of year-to-year changes in global climate and lake environments. Because phytoplankton size structure is an important factor in the material cycle (Ray et al, 2001;Law et al, 2009) and trophic structure (Kazama et al, 2021b) in lakes, it is necessary to determine the response of local phytoplankton communities to global climate change in order to develop better conservation and management plans for aquatic ecosystems in the future.…”

Impact of climate change and oligotrophication on quality and quantity of lake primary production: A case study in Lake Biwa

“…Strengthened stratification and oligotrophic conditions prevail in the mixed layer under global warming, favoring small phytoplankton dominance (Falkowski & Oliver, 2007; Winder et al, 2009; Zohary et al, 2021). Given that key herbivorous zooplankton, such as Daphnia and copepods, feed on smaller PP sizes, with 20–50 μm being the limit (Lampert & Sommer, 2007), downsizing PP affects trophic structure (Kazama et al, 2021c) and material cycling (Ray et al, 2001; Law et al, 2009). Therefore, considering long-term PP changes necessitates examining the qualitative aspect of size structure.…”