scholarly journals Higher order interactions and species coexistence

2020 ◽  
Author(s):  
Pragya Singh ◽  
Gaurav Baruah
Keyword(s):  
Intraspecific Competition ◽  
Species Interactions ◽  
Species Coexistence ◽  
General Rule ◽  
Higher Order ◽  
Volterra Model ◽  
Ecological Communities ◽  
Wide Range ◽  
Analytical Result ◽  
Underlying Mechanisms

AbstractHigher order interactions (HOIs) have been suggested to stabilize diverse ecological communities. However, their role in maintaining species coexistence from the perspective of modern coexistence theory is not known. Here, using generalized Lotka-Volterra model, we derive a general rule for species coexistence modulated by HOIs. We show that where pairwise species interactions fail to promote species coexistence in regions of extreme fitness differences, negative HOIs that intensify pairwise competition, however, can promote coexistence provided that HOIs strengthen intraspecific competition more than interspecific competition. In contrast, positive HOIs that alleviate pairwise competition can stabilize coexistence across a wide range of fitness differences, irrespective of differences in strength of inter- and intraspecific competition. In addition, we extend our three-species analytical result to multispecies communities and show, using simulations, that multispecies coexistence is possible provided that strength of negative intraspecific HOIs is higher than interspecific HOIs. Our work sheds light on the underlying mechanisms through which HOIs can maintain species diversity.

scholarly journals Higher order interactions and coexistence theory

2019 ◽  
Author(s):  
Pragya Singh ◽  
Gaurav Baruah
Keyword(s):  
Intraspecific Competition ◽  
Species Coexistence ◽  
General Rule ◽  
Higher Order ◽  
Volterra Model ◽  
Ecological Communities ◽  
Coexistence Theory ◽  
Wide Range ◽  
Analytical Result ◽  
Underlying Mechanisms

AbstractHigher order interactions (HOIs) have been suggested to stabilize diverse ecological communities. However, their role in maintaining species coexistence from the perspective of modern coexistence theory is unknown. Here, using a three-species Lotka-Volterra model, we derive a general rule for species coexistence modulated by HOIs. We show that negative HOIs that intensify pairwise competition, can promote coexistence across a wide range of fitness differences, provided that HOIs strengthen intraspecific competition more than interspecific competition. In contrast, positive HOIs that alleviate pairwise competition can also stabilize coexistence across a wide range of fitness differences, irrespective of differences in strength of inter- and intraspecific competition. Furthermore, we extend our three-species analytical result to multispecies competitive community and show, using simulations, that feasible multispecies coexistence is possible provided that strength of negative intraspecific HOIs is higher than interspecific HOIs. In addition, multispecies communities, however, become unstable with positive HOIs as such higher-order interactions could lead to disproportionately infeasible growth rates. This work provides crucial insights on the underlying mechanisms that could maintain species diversity and links HOIs with modern coexistence theory.

scholarly journals Intraspecific variation promotes species coexistence and trait clustering through higher order interactions

2018 ◽  
Author(s):  
Gaurav Baruah ◽  
Robert John
Keyword(s):  
Intraspecific Variation ◽  
Individual Variation ◽  
Species Coexistence ◽  
Species Traits ◽  
Higher Order ◽  
Competitive Interactions ◽  
Volterra Model ◽  
Trait Divergence ◽  
Pairwise Interactions ◽  
Coexisting Species

AbstractEcological and evolutionary effects of individual variation on species coexistence remains unclear. Competition models for coexistence have emphasized species-level differences in pairwise interactions, and invoked no role for intraspecific variation. These models show that stronger competitive interactions result in smaller numbers of coexisting species. However, the presence of higher-order interactions (HOIs) among species appears to have a stabilizing influence on communities. How species coexistence is affected in a community where both pairwise and higher-order interactions are pervasive is not known. Furthermore, the effect of individual variation on species coexistence in complex communities with pairwise and HOIs remains untested. Using a Lotka-Volterra model, we explore the effects of intraspecific variation on the patterns of species coexistence in a competitive community dictated by pairwise and HOIs. We found that HOIs greatly stabilize species coexistence across different levels of strength in competition. Notably, high intraspecific variation promoted species coexistence, particularly when competitive interactions were strong. However, species coexistence promoted by higher levels of variation was less robust to environmental perturbation. Additionally, species’ traits tend to cluster together when individual variation in the community increased. We argue that individual variation can promote species coexistence by reducing trait divergence and attenuating the inhibitory effects of dominant species through HOIs

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 Idea Paper: improving forecasts of community composition with lightweight biodiversity monitoring across ecological and anthropogenic disturbance gradients

2021 ◽  
Author(s):  
Jamie M. Kass ◽  
Nao Takashina ◽  
Nicholas Friedman ◽  
Buntarou Kusumoto ◽  
Mary E. Blair
Keyword(s):  
Community Composition ◽  
Species Interactions ◽  
Anthropogenic Disturbance ◽  
Ecological Communities ◽  
Geographic Patterns ◽  
Wide Range ◽  
Community Data ◽  
Passive Sensors ◽  
Different Dimensions ◽  
Management And Conservation

Accurate and up-to-date biodiversity forecasts enable robust planning for environmental management and conservation of landscapes under a wide range of uses. Future predictions of the species composition of ecological communities complement more frequently reported species richness estimates to better characterize the different dimensions of biodiversity. The models that make community composition forecasts are calibrated with data on species’ geographic patterns for the present, which may not be good proxies for future patterns. The future establishment of novel communities represents data on species interactions unaccounted for by these models. However, detecting them in a systematic way presents challenges due to the lack of monitoring data for landscapes with high environmental turnover, where such communities are likely to establish. Here, we propose lightweight monitoring over both ecological and anthropogenic disturbance gradients using passive sensors (i.e., those that operate continuously without much human input) to detect novel communities with the aim of updating models that make community composition forecasts. Monitoring over these two gradients should maximize detection of novel communities and improve understanding of relationships between community composition and environmental change. Further, barriers regarding cost and effort are reduced by using relatively few sensors requiring minimal upkeep. Ongoing updates to community composition forecasts based on novel community data and better understanding of the associated uncertainty should improve future decision-making for both resource management and conservation efforts.

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 A process-based metacommunity framework linking local and regional scale community ecology

2019 ◽  
Author(s):  
Patrick L. Thompson ◽  
Laura Melissa Guzman ◽  
Luc De Meester ◽  
Zsófia Horváth ◽  
Robert Ptacnik ◽  
...  
Keyword(s):  
Simulation Model ◽  
Community Ecology ◽  
Species Interactions ◽  
Community Dynamics ◽  
Regional Scale ◽  
Ecological Communities ◽  
Data Accessibility ◽  
Species Sorting ◽  
Wide Range ◽  
Underlying Processes

AbstractThe metacommunity concept has the potential to integrate local and regional dynamics within a general community ecology framework. To this end, the concept must move beyond the discrete archetypes that have largely defined it (e.g. neutral vs. species sorting) and better incorporate local scale species interactions and coexistence mechanisms. Here, we present a fundamental reconception of the framework that explicitly links local coexistence theory to the spatial processes inherent to metacommunity theory, allowing for a continuous range of competitive community dynamics. These dynamics emerge from the three underlying processes that shape ecological communities: 1) density-independent responses to abiotic conditions, 2) density-dependent biotic interactions, and 3) dispersal. Stochasticity is incorporated in the demographic realization of each of these processes. We formalize this framework using a simulation model that explores a wide range of competitive metacommunity dynamics by varying the strength of the underlying processes. Using this model and framework, we show how existing theories, including the traditional metacommunity archetypes, are linked by this common set of processes. We then use the model to generate new hypotheses about how the three processes combine to interactively shape diversity, functioning, and stability within metacommunities.Statement of authorshipThis project was conceived at the sTURN working group, of which all authors are members. PLT developed the framework and model with input from all authors. PLT wrote the model code. PLT and LMG performed the simulations. PLT produced the figures and wrote the first draft with input from LMG and JMC. All authors provided feedback and edits on several versions of the manuscript.Data accessibilityAll code for running the simulation model and producing the figures is archived on Zenodo - https://doi.org/10.5281/zenodo.3833035.

scholarly journals Community context modifies response of host-parasitoid interactions to phenological mismatch under warming

2021 ◽  
Author(s):  
Nicholas Pardikes ◽  
Tomas Revilla ◽  
Chia-Hua Lue ◽  
Melanie Thierry ◽  
Daniel Souto-Villaros ◽  
...  
Keyword(s):  
Intraspecific Competition ◽  
Host Species ◽  
Species Interactions ◽  
Community Context ◽  
Ecological Communities ◽  
Alternative Host ◽  
Parasitism Rates ◽  
Future Global Warming ◽  
Phenological Shifts ◽  
Community Contexts

Climate change is altering the relative timing of species interactions by shifting when species appear in a community and by accelerating developmental rates. However, phenological shifts may be mediated through community contexts, such as intraspecific competition and alternative resource species, which can prolong the otherwise shortened windows of availability. Using a combination of laboratory experiments and dynamic simulations, we quantified how the effects of phenological shifts in Drosophila-parasitoid interactions differed with concurrent changes in temperature, intraspecific competition, and the presence of alternative host species. We found that community context, particularly the presence of alternative host species, supported interaction persistence across a wider range of phenological shifts than pairwise interactions. Parasitism rates declined under warming, which limited the ability of community contexts to manage mismatched interactions. These results demonstrate that ongoing declines in insect diversity may exacerbate the effects of phenological shifts in ecological communities under future global warming temperatures.

scholarly journals Emergent phases of ecological diversity and dynamics mapped in microcosms

2021 ◽  
Author(s):  
Jiliang Hu ◽  
Daniel R. Amor ◽  
Matthieu Barbier ◽  
Guy Bunin ◽  
Jeff Gore
Keyword(s):  
Species Interactions ◽  
Stable Equilibrium ◽  
Species Abundance ◽  
Ecological Communities ◽  
Ecological Diversity ◽  
Unified Framework ◽  
Complex Systems Theory ◽  
Microbial Ecosystems ◽  
Wide Range ◽  
Emergent Behaviors

Natural ecological communities display striking features, such as high biodiversity and a wide range of dynamics, that have been difficult to explain in a unified framework. Using experimental bacterial microcosms, we perform the first direct test of recent complex systems theory predicting that simple aggregate parameters dictate emergent behaviors of the community. As either the number of species or the strength of species interactions is increased, we show that microbial ecosystems transition between distinct qualitative dynamical phases in the predicted order, from a stable equilibrium where all species coexist, to partial coexistence, to emergence of persistent fluctuations in species abundance. Under the same conditions, high biodiversity and fluctuations allow and require each other. Our results demonstrate predictable emergent diversity and dynamics in ecological communities.

scholarly journals Habitat loss alters effects of intransitive higher-order competition on biodiversity: a new metapopulation framework

2020 ◽  
Vol 287 (1940) ◽  
pp. 20201571
Author(s):  
Yinglin Li ◽  
Daniel Bearup ◽  
Jinbao Liao
Keyword(s):  
Habitat Loss ◽  
Species Interactions ◽  
Species Coexistence ◽  
Interaction Model ◽  
Higher Order ◽  
Community Diversity ◽  
Rapid Decline ◽  
Order Effects ◽  
Vital Rates ◽  
Model Framework

Recent studies have suggested that intransitive competition, as opposed to hierarchical competition, allows more species to coexist. Furthermore, it is recognized that the prevalent paradigm, which assumes that species interactions are exclusively pairwise, may be insufficient. More importantly, whether and how habitat loss, a key driver of biodiversity loss, can alter these complex competition structures (and therefore species coexistence) remain unclear. We thus present a new, simple yet comprehensive metapopulation framework that can account for any competition pattern and more complex higher-order interactions (HOIs) among species. We find that competitive intransitivity increases community diversity and that HOIs generally enhance this effect. Essentially, intransitivity promotes species richness by preventing the dominance of a few species, unlike the hierarchical competition, while HOIs facilitate species coexistence through stabilizing community fluctuations. However, variation in species’ vital rates and habitat loss can weaken or even reverse such higher-order effects, as their interaction can lead to a more rapid decline in competitive intransitivity under HOIs. Thus, it is essential to correctly identify the most appropriate interaction model for a given system before models are used to inform conservation efforts. Overall, our simple model framework provides a more parsimonious explanation for biodiversity maintenance than the existing theory.

scholarly journals Species coexistence in resource-limited patterned ecosystems is facilitated by the interplay of spatial self-organisation and intraspecific competition

2020 ◽  
Author(s):  
Lukas Eigentler
Keyword(s):  
Intraspecific Competition ◽  
Species Coexistence ◽  
Stress Gradient ◽  
Woody Species ◽  
Vegetation Patterns ◽  
Functional Responses ◽  
Resource Limited ◽  
Wide Range ◽  
Self Organisation ◽  
Resource Input

The exploration of mechanisms that enable species coexistence under competition for a sole limiting resource is widespread across ecology. Two examples of such facilitative processes are intraspecific competition and spatial self-organisation. These processes determine the outcome of competitive dynamics in many resource-limited patterned ecosystems, classical examples of which include dryland vegetation patterns, intertidal mussel beds and Subalpine ribbon forests. Previous theoretical investigations have explained coexistence within patterned ecosystems by making strong assumptions on the differences between species (e.g. contrasting dispersal behaviours or different functional responses to resource availability). In this paper, I show that the interplay between the detrimental effects of intraspecific competition and the facilitative nature of self-organisation forms a coexistence mechanism that does not rely on species-specific assumptions and captures coexistence across a wide range of the environmental stress gradient. I use a theoretical model that captures the interactions of two generic consumer species with an explicitly modelled resource to show that coexistence relies on a balance between species' colonisation abilities and their local competitiveness, provided intraspecific competition is sufficiently strong. Crucially, the requirements on species' self-limitation for coexistence to occur differ on opposite ends of the resource input spectrum. For low resource levels, coexistence is facilitated by strong intraspecific dynamics of the species superior in its colonisation abilities, but for larger volumes of resource input, strong intraspecific competition of the locally superior species enables coexistence. Results presented in this paper also highlight the importance of hysteresis in understanding tipping points, in particular extinction events. Finally, the theoretical framework provides insights into spatial species distributions within single patches, supporting verbal hypotheses on coexistence of herbaceous and woody species in dryland vegetation patterns and suggesting potential empirical tests in the context of other patterned ecosystems.

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