scholarly journals Vulnerable species interactions are important for the stability of mutualistic networks

2019 ◽  
Author(s):  
Benno I. Simmons ◽  
Hannah S. Wauchope ◽  
Tatsuya Amano ◽  
Lynn V. Dicks ◽  
William J. Sutherland ◽  
...  
Keyword(s):  
Species Interactions ◽  
Species Coexistence ◽  
Species Interaction ◽  
Interaction Networks ◽  
Ecological Communities ◽  
Ecological Context ◽  
Intrinsic Properties ◽  
Network Stability ◽  
Starting Point ◽  
The Stability

AbstractSpecies are central to ecology and conservation. However, it is the interactions between species that generate the functions on which ecosystems and humans depend. Despite the importance of interactions, we lack an understanding of the risk that their loss poses to ecological communities. Here, we quantify risk as a function of the vulnerability (likelihood of loss) and importance (contribution to network stability in terms of species coexistence) of 4330 mutualistic interactions from 41 empirical pollination and seed dispersal networks across six continents. Remarkably, we find that more vulnerable interactions are also more important: the interactions that contribute most to network stability are those that are most likely to be lost. Furthermore, most interactions tend to have more similar vulnerability and importance across networks than expected by chance, suggesting that vulnerability and importance may be intrinsic properties of interactions, rather than only a function of ecological context. These results provide a starting point for prioritising interactions for conservation in species interaction networks and, in areas lacking network data, could allow interaction properties to be inferred from taxonomy alone.

scholarly journals Effect of Localization on the Stability of Mutualistic Ecological Networks

2015 ◽  
Author(s):  
Samir Suweis ◽  
Jacopo Grilli ◽  
Jayanth Banavar ◽  
Stefano Allesina ◽  
Amos Maritan
Keyword(s):  
Species Abundance ◽  
Interaction Network ◽  
Species Interaction ◽  
Interaction Networks ◽  
Ecological Communities ◽  
Weighted Degree ◽  
Perturbation Propagation ◽  
The Stability ◽  
The Impact ◽  
The Relationship

The relationships between the core-periphery architecture of the species interaction network and the mechanisms ensuring the stability in mutualistic ecological communities are still unclear. In particular, most studies have focused their attention on asymptotic resilience or persistence, neglecting how perturbations propagate through the system. Here we develop a theoretical framework to evaluate the relationship between architecture of the interaction networks and the impact of perturbations by studying localization, a measure describing the ability of the perturbation to propagate through the network. We show that mutualistic ecological communities are localized, and localization reduces perturbation propagation and attenuates its impact on species abundance. Localization depends on the topology of the interaction networks, and it positively correlates with the variance of the weighted degree distribution, a signature of the network topological hetereogenity. Our results provide a different perspective on the interplay between the architecture of interaction networks in mutualistic communities and their stability.

scholarly journals The balance of interaction types determines the assembly and stability of ecological communities

2019 ◽  
Author(s):  
Jimmy J. Qian ◽  
Erol Akçay
Keyword(s):  
Species Interactions ◽  
Community Dynamics ◽  
Theoretical Work ◽  
Species Interaction ◽  
Ecological Communities ◽  
External Stability ◽  
Ecological Selection ◽  
Interaction Types ◽  
The Stability ◽  
Almost All

What determines the assembly and stability of complex communities is a central question in ecology. Past work has suggested that mutualistic interactions are inherently destabilizing. However, this conclusion relies on assuming that benefits from mutualisms never stop increasing. Furthermore, almost all theoretical work focuses on the internal (asymptotic) stability of communities assembled all-at-once. Here, we present a model with saturating benefits from mutualisms and sequentially assembled communities. We show that such communities are internally stable for any level of diversity and any combination of species interaction types. External stability, or resistance to invasion, is thus an important but overlooked measure of stability. We demonstrate that the balance of different interaction types governs community dynamics. Mutualisms may increase external stability and diversity of communities as well as species persistence, depending on how benefits saturate. Ecological selection increases the prevalence of mutualisms, and limits on biodiversity emerge from species interactions. Our results help resolve longstanding debates on the stability, saturation, and diversity of communities.

scholarly journals Dynamic population stage structure due to juvenile–adult asymmetry stabilizes complex ecological communities

2021 ◽  
Vol 118 (21) ◽  
pp. e2023709118
Author(s):  
André M. de Roos
Keyword(s):  
Self Regulation ◽  
Interaction Network ◽  
Population Level ◽  
Stage Structure ◽  
Current Theory ◽  
Species Interaction ◽  
Interaction Matrix ◽  
Foraging Efficiency ◽  
Ecological Communities ◽  
The Stability

Natural ecological communities are diverse, complex, and often surprisingly stable, but the mechanisms underlying their stability remain a theoretical enigma. Interactions such as competition and predation presumably structure communities, yet theory predicts that complex communities are stable only when species growth rates are mostly limited by intraspecific self-regulation rather than by interactions with resources, competitors, and predators. Current theory, however, considers only the network topology of population-level interactions between species and ignores within-population differences, such as between juvenile and adult individuals. Here, using model simulations and analysis, I show that including commonly observed differences in vulnerability to predation and foraging efficiency between juvenile and adult individuals results in up to 10 times larger, more complex communities than observed in simulations without population stage structure. These diverse communities are stable or fluctuate with limited amplitude, although in the model only a single basal species is self-regulated, and the population-level interaction network is highly connected. Analysis of the species interaction matrix predicts the simulated communities to be unstable but for the interaction with the population-structure subsystem, which completely cancels out these instabilities through dynamic changes in population stage structure. Common differences between juveniles and adults and fluctuations in their relative abundance may hence have a decisive influence on the stability of complex natural communities and their vulnerability when environmental conditions change. To explain community persistence, it may not be sufficient to consider only the network of interactions between the constituting species.

scholarly journals Genetics-based interactions of foundation species affect community diversity, stability and network structure

2017 ◽  
Vol 284 (1854) ◽  
pp. 20162703 ◽  
Author(s):  
Arthur R. Keith ◽  
Joseph K. Bailey ◽  
Matthew K. Lau ◽  
Thomas G. Whitham
Keyword(s):  
Network Structure ◽  
Experimental Manipulation ◽  
Species Interaction ◽  
Foundation Species ◽  
Interaction Networks ◽  
Community Diversity ◽  
Arthropod Community ◽  
Pemphigus Betae ◽  
In The Wild ◽  
The Stability

We examined the hypothesis that genetics-based interactions between strongly interacting foundation species, the tree Populus angustifolia and the aphid Pemphigus betae , affect arthropod community diversity, stability and species interaction networks of which little is known. In a 2-year experimental manipulation of the tree and its aphid herbivore four major findings emerged: (i) the interactions of these two species determined the composition of an arthropod community of 139 species; (ii) both tree genotype and aphid presence significantly predicted community diversity; (iii) the presence of aphids on genetically susceptible trees increased the stability of arthropod communities across years; and (iv) the experimental removal of aphids affected community network structure (network degree, modularity and tree genotype contribution to modularity). These findings demonstrate that the interactions of foundation species are genetically based, which in turn significantly contributes to community diversity, stability and species interaction networks. These experiments provide an important step in understanding the evolution of Darwin's ‘entangled bank’, a metaphor that characterizes the complexity and interconnectedness of communities in the wild.

A roadmap towards predicting species interaction networks (across space and time)

2021 ◽  
Vol 376 (1837) ◽  
pp. 20210063 ◽  
Author(s):  
Tanya Strydom ◽  
Michael D. Catchen ◽  
Francis Banville ◽  
Dominique Caron ◽  
Gabriel Dansereau ◽  
...  
Keyword(s):  
Species Interactions ◽  
False Negative ◽  
Research Programme ◽  
Species Interaction ◽  
Ecological Networks ◽  
Ecological Communities ◽  
True Negative ◽  
Structure Variation ◽  
Space And Time ◽  
Simple Neural Network

Networks of species interactions underpin numerous ecosystem processes, but comprehensively sampling these interactions is difficult. Interactions intrinsically vary across space and time, and given the number of species that compose ecological communities, it can be tough to distinguish between a true negative (where two species never interact) from a false negative (where two species have not been observed interacting even though they actually do). Assessing the likelihood of interactions between species is an imperative for several fields of ecology. This means that to predict interactions between species—and to describe the structure, variation, and change of the ecological networks they form—we need to rely on modelling tools. Here, we provide a proof-of-concept, where we show how a simple neural network model makes accurate predictions about species interactions given limited data. We then assess the challenges and opportunities associated with improving interaction predictions, and provide a conceptual roadmap forward towards predictive models of ecological networks that is explicitly spatial and temporal. We conclude with a brief primer on the relevant methods and tools needed to start building these models, which we hope will guide this research programme forward. This article is part of the theme issue ‘Infectious disease macroecology: parasite diversity and dynamics across the globe’.

scholarly journals Combined Impacts of Predation, Mutualism and Dispersal on the Dynamics of a Four-Species Ecological System

2021 ◽  
Vol 29 (1) ◽  
Author(s):  
Murtala Bello Aliyu ◽  
Mohd Hafiz Mohd
Keyword(s):  
Hopf Bifurcation ◽  
Species Interactions ◽  
Species Coexistence ◽  
Biotic Interactions ◽  
Ecological System ◽  
Stable Limit ◽  
Combined Effects ◽  
Coexistence Mechanisms ◽  
Multiple Species ◽  
The Stability

Multi-species and ecosystem models have provided ecologist with an excellent opportunity to study the effects of multiple biotic interactions in an ecological system. Predation and mutualism are among the most prevalent biotic interactions in the multi-species system. Several ecological studies exist, but they are based on one-or two-species interactions, and in real life, multiple interactions are natural characteristics of a multi-species community. Here, we use a system of partial differential equations to study the combined effects of predation, mutualism and dispersal on the multi-species coexistence and community stability in the ecological system. Our results show that predation provided a defensive mechanism against the negative consequences of the multiple species interactions by reducing the net effect of competition. Predation is critical in the stability and coexistence of the multi-species community. The combined effects of predation and dispersal enhance the multiple species coexistence and persistence. Dispersal exerts a positive effect on the system by supporting multiple species coexistence and stability of community structures. Dispersal process also reduces the adverse effects associated with multiple species interactions. Additionally, mutualism induces oscillatory behaviour on the system through Hopf bifurcation. The roles of mutualism also support multiple species coexistence mechanisms (for some threshold values) by increasing the stable coexistence and the stable limit cycle regions. We discover that the stability and coexistence mechanisms are controlled by the transcritical and Hopf bifurcation that occurs in this system. Most importantly, our results show the important influences of predation, mutualism and dispersal in the stability and coexistence of the multi-species communities

Species in variable environments

2019 ◽  
pp. 287-306
Author(s):  
Gary G. Mittelbach ◽  
Brian J. McGill
Keyword(s):  
Environmental Change ◽  
Species Interactions ◽  
Species Coexistence ◽  
Dynamic State ◽  
Ecological Communities ◽  
Variable Environments ◽  
Degraded Ecosystems ◽  
Alternative Community ◽  
Response To Environmental Change ◽  
Alternative Community States

Species and communities may exist in a dynamic state of change in response to environmental variation and disturbance. This chapter explores the consequences of variable environments and disturbance to species interactions and community structure. In particular, it examines how disturbance can result in the succession of ecological communities, how disturbance may promote (or hinder) species coexistence, how a varying environment can promote species coexistence through a mechanism called the “storage effect”, and how communities may shift between alternative states in response to environmental change. The latter topic is particularly relevant to the management of biotic resources and the restoration of degraded ecosystems, as systems may respond to environmental change abruptly at a “tipping point”, leading to alternative community states that can be difficult to reverse.

scholarly journals Strength of species interactions determines biodiversity and stability in microbial communities

2019 ◽  
Author(s):  
Christoph Ratzke ◽  
Julien Barrere ◽  
Jeff Gore
Keyword(s):  
Microbial Communities ◽  
Species Interactions ◽  
Microbial Growth ◽  
Species Interaction ◽  
Nutrient Concentrations ◽  
History Of Research ◽  
Microbial Ecosystems ◽  
High Nutrient ◽  
History Of ◽  
The Stability

AbstractOrganisms – especially microbes – tend to live in complex communities. While some of these ecosystems are very bio-diverse, others aren’t1–3, and while some are very stable over time others undergo strong temporal fluctuations4,5. Despite a long history of research and a plethora of data it is not fully understood what sets biodiversity and stability of ecosystems6,7. Theory as well as experiments suggest a connection between species interaction, biodiversity, and stability of ecosystems8–13, where an increase of ecosystem stability with biodiversity could be observed in several cases7,9,14. However, what causes these connections remains unclear. Here we show in microbial ecosystems in the lab that the concentrations of available nutrients can set the strength of interactions between bacteria. At high nutrient concentrations, extensive microbial growth leads to strong chemical modifications of the environment, causing more negative interactions between species. These stronger interactions exclude more species from the community – resulting in a loss of biodiversity. At the same time, these stronger interactions also decrease the stability of the microbial communities, providing a mechanistic link between species interaction, biodiversity and stability.

scholarly journals Classification of Biological Interactions: Challenges in the field and in analysis

2021 ◽  
Vol 5 ◽  
Author(s):  
Rafael Pinheiro ◽  
Leonardo Jorge ◽  
Thomas Lewinsohn
Keyword(s):  
Species Interactions ◽  
Biotic Interactions ◽  
Field Studies ◽  
Species Interaction ◽  
Ecological Communities ◽  
Biological Interactions ◽  
Web Database ◽  
Online Databases ◽  
Living Organisms ◽  
Taxonomic Groups

Within biological communities, species interact in a wide variety of ways. Species interactions have always been noted and classified by naturalists in describing living organisms and their ways. Moreover, they are essential to characterize ecological communities as functioning entities. Biodiversity databases, as a rule, are comprised of species records in certain localities and times. Many, if not most, originated as databases of museum specimens and/or published records. As such, they provide data on species occurrences and distribution, with little functional information. Currently, online databases for species interaction data are being formed or proposed. Usually, these databases set out to compile data from actual field studies, and their design reflects the singularities of particular studies that seed their development. In two online databases: the Web of Life (2021) and the Interaction Web DataBase (2020) (IWDB), the categories of interactions are quite heterogeneous (Table 1). For instance, they may refer explicitly to certain taxonomic groups (e.g., anemone-fish), or do so implicitly (host-parasitoid; parasitoids are all holometabolous insects with arthropod hosts); conversely, they may encompass almost any taxon (food webs). In another example, the Global Biotic Interactions database (Poelen et al. 2014) (GloBI) offers a choice of relational attributes when entering data, ranging from undefined to quite restricted (Table 2). Here we intend to contribute to the development of interaction databases, from two different points of view. First, what categories can be effectively applied to field observations of biotic interactions? Second, what theoretical and applied questions do we expect to address with interaction databases? These should be equally applicable to comparisons of studies of the same kind or mode of interaction, and to contrasts between interactions in multimodal studies.

scholarly journals Beyond species: why ecological interaction networks vary through space and time

2014 ◽  
Author(s):  
Timothée Poisot ◽  
Daniel B Stouffer ◽  
Dominique Gravel
Keyword(s):  
Species Interactions ◽  
Scale Up ◽  
Predictive Ability ◽  
Population Based ◽  
Species Interaction ◽  
Interaction Networks ◽  
Future Research ◽  
Intrinsic Variability ◽  
New Approach ◽  
Emerging Ecosystems

Community ecology is tasked with the considerable challenge of predicting the structure, and properties, of emerging ecosystems. It requires the ability to understand how and why species interact, as this will allow the development of mechanism-based predictive models, and as such to better characterize how ecological mechanisms act locally on the existence of inter-specific interactions. Here we argue that the current conceptualization of species interaction networks is ill-suited for this task. Instead, we propose that future research must start to account for the intrinsic variability of species interactions, then scale up from here onto complex networks. This can be accomplished simply by recognizing that there exists intra-specific variability, in traits or properties related to the establishment of species interactions. By shifting the scale towards population-based processes, we show that this new approach will improve our predictive ability and mechanistic understanding of how species interact over large spatial or temporal scales.

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