Variable and complex food web structures revealed by exploring missing trophic links between birds and biofilm.Ecol.Lett

Abstract Food webs are comprised of a network of trophic interactions and are essential to elucidating ecosystem processes and functions. However, the presence of unknown, but critical networks hampers understanding of complex and dynamic food webs in nature. Here, we empirically demonstrate a missing link, both critical and variable, by revealing that direct predator-prey relationships between shorebirds and biofilm are widespread and mediated by multiple ecological and evolutionary determinants. Food source mixing models and energy budget estimates indicate that the strength of the missing linkage is dependent on predator traits (body mass and foraging action rate) and the environment that determines food density. Morphological analyses, showing that smaller bodied species possess more developed feeding apparatus to consume biofilm, suggest that the linkage is also phylogenetically dependent and affords a compelling re-interpretation of niche differentiation. We contend that exploring missing links is a necessity for revealing true network structure and dynamics

Microbial community ecosystem network model for chemical energy transport

Microorganisms thriving in low-energy ecosystems have evolved diverse strategies to sustain life, including individual-level energy conservation, optimizing energy utilization through interspecies competition, and mutually beneficial interspecies syntrophy. This study introduces a novel community-level strategy to enhance energy efficiency. We employed an oxidation-reduction (redox) reaction network model to capture the intricate metabolic interactions within microbial communities. Our findings highlight the importance of microbial functional diversity in facilitating metabolic handoffs, leading to an improved energy utilization efficiency. Moreover, the mutualistic division of labor and the resulting complexity of redox pathways actively facilitate material cycling, thereby enhancing energy exploitation. These findings provide new insights into the potential of self-organized ecological interactions to develop efficient energy utilization strategies, with significant implications for the functioning and evolution of microbial ecosystems

Kyogoku.Kondoh.Sota.2019.Ecol.Evol.data

Replicated experimental evolution lines of Callosobruchus chinensis (beetle) first evolved under either polygamy or monogamy. These experimental evolution lines then competed with Callosobruchus maculatus. All trials resulted in the extinction of C. chinensis. The data file includes time until extinction, and demographyc dynamics of the competition for a subset of the replications

Electronic Supplementary Material from Density-dependent interspecific interactions and the complexity–stability relationship

including local stability analysis of the classical functional response and figures of the additional analysi

Functional diversity of microbial decomposers facilitates plant coexistence in a plant–microbe–soil feedback model

Theory and empirical evidence suggest that plant–soil feedback (PSF) determines the structure of a plant community and nutrient cycling in terrestrial ecosystems. The plant community alters the nutrient pool size in soil by affecting litter decomposition processes, which in turn shapes the plant community, forming a PSF system. However, the role of microbial decomposers in PSF function is often overlooked, and it remains unclear whether decomposers reinforce or weaken litter-mediated plant control over nutrient cycling. Here, we present a theoretical model incorporating the functional diversity of both plants and microbial decomposers. Two fundamental microbial processes are included that control nutrient mineralization from plant litter: (i) assimilation of mineralized nutrient into the microbial biomass (microbial immobilization), and (ii) release of the microbial nutrients into the inorganic nutrient pool (net mineralization). With this model, we show that microbial diversity may act as a buffer that weakens plant control over the soil nutrient pool, reversing the sign of PSF from positive to negative and facilitating plant coexistence. This is explained by the decoupling of litter decomposability and nutrient pool size arising from a flexible change in the microbial community composition and decomposition processes in response to variations in plant litter decomposability. Our results suggest that the microbial community plays a central role in PSF function and the plant community structure. Furthermore, the results strongly imply that the plant-centered view of nutrient cycling should be changed to a plant–microbe–soil feedback system, by incorporating the community ecology of microbial decomposers and their functional diversity

Dataset for: Integrated trophic position as a proxy for food-web complexity

<div> <p>There are two distinct approaches to describing the distributions of biomass and species in food webs: one to consider them as discrete trophic levels (TLs); and the other to consider them as continuous trophic positions (TPs). Bridging the gap between these two perspectives presents a non-trivial challenge in integrating biodiversity and food-web structure.</p> <p>Food Network Unfolding (FNU) is a technique used to bridge this gap by partitioning the biomass of species into integer TLs to compute three complexity indices, namely vertical (<em>D</em><sub>V</sub>), horizontal (<em>D</em><sub>H</sub>), and range (<em>D</em><sub>R</sub>) diversity (<em>D</em> indices), through decomposition of Shannon's index <em>H'</em>. Using FNU, the food web (a network of species with unique TPs) is converted to a linear food chain (a biomass distribution at discrete TLs). This enables us to expect that the unfolded biomass within species decreases exponentially as the TL increases. Under this condition, the mean TL value in unfolded food chains is hypothesized to have an exponential relationship with the vertical diversity, <em>D</em><sub>V</sub>. To explore this, we implemented FNU and calculated <em>D</em> indices for food webs publicly available at EcoBase (<em>n</em> = 158) and calculated the integrated TP (iTP), defined as the biomass-weighted average TP of a given food web. The iTP corresponds to the mean TL in unfolded food chains and can be empirically measured through compound-specific isotope analysis of amino acids (CSIA-AA).</p> <p>Although our analysis is biased towards marine ecosystems, we revealed an exponential relationship between iTP and <em>D</em><sub>V</sub>, suggesting that iTP can serve as a measurable proxy for <em>D</em><sub>V</sub>. Furthermore, we found a positive correlation between the iTP observed in the total communities (total iTP) and the iTPs of partial communities consisting only of species with 2.0 ≤ TP < 3.0 (partial iTP; <em>r<sup>2</sup></em> = 0.48), suggesting that <em>D</em><sub>V</sub> can be predicted using partial iTP.</p> <p>Our findings suggest that the net effect of species diversity, excluding the effect of biomass (corresponding to <em>H'</em> − <em>D</em><sub>V</sub>), on food-web complexity can be revealed by combining CSIA-AA with biodiversity analysis (e.g., environmental DNA).</p> </div><p>Funding provided by: Japan Society for the Promotion of Science<br>Crossref Funder Registry ID: https://ror.org/00hhkn466<br>Award Number: 22K19857</p><p>The dataset was collected from <a href="http://ecobase.ecopath.org" rel="noopener">EcoBase</a> and processed using R and Matlab codes (pickupdata.R, createcolormap.m, and script.m).</p> <p>Details are provided in the README file.</p&gt