A search for maximum species abundances in ecological communities under conditional diversity optimization

1997 ◽  
Vol 59 (4) ◽  
pp. 649-677
Author(s):  
V Alexeyev
Keyword(s):  
Ecological Communities ◽  
Species Abundances

scholarly journals Remembrance of things past: modelling the relationship between species' abundances in living communities and death assemblages

2011 ◽  
Vol 8 (1) ◽  
pp. 131-134 ◽  
Author(s):  
Thomas D. Olszewski
Keyword(s):  
Half Life ◽  
Species Differences ◽  
Species Abundance ◽  
Time Averaging ◽  
Ecological Communities ◽  
Post Mortem ◽  
Death Assemblages ◽  
Species Abundances ◽  
The Relationship ◽  
Range Of Variation

Accumulations of dead skeletal material are a valuable archive of past ecological conditions. However, such assemblages are not equivalent to living communities because they mix the remains of multiple generations and are altered by post-mortem processes. The abundance of a species in a death assemblage can be quantitatively modelled by successively integrating the product of an influx time series and a post-mortem loss function (a decay function with a constant half-life). In such a model, temporal mixing increases expected absolute dead abundance relative to average influx as a linear function of half-life and increases variation in absolute dead abundance values as a square-root function of half-life. Because typical abundance distributions of ecological communities are logarithmically distributed, species' differences in preservational half-life would have to be very large to substantially alter species' abundance ranks (i.e. make rare species common or vice-versa). In addition, expected dead abundances increase at a faster rate than their range of variation with increased time averaging, predicting greater consistency in the relative abundance structure of death assemblages than their parent living community.

scholarly journals Distance decay 2.0 – a global synthesis of taxonomic and functional turnover in ecological communities

2021 ◽  
Author(s):  
Caio Graco-Roza ◽  
Sonja Aarnio ◽  
Nerea Abrego ◽  
Alicia T. R. Acosta ◽  
Janne Alahuhta ◽  
...  
Keyword(s):  
Community Composition ◽  
Linear Models ◽  
Distance Decay ◽  
Spatial Distance ◽  
Ecological Communities ◽  
Β Diversity ◽  
Functional Distance ◽  
Holistic Understanding ◽  
Species Abundances ◽  
Rate Of Decay

AbstractUnderstanding the variation in community composition and species abundances, i.e., β-diversity, is at the heart of community ecology. A common approach to examine β-diversity is to evaluate directional turnover in community composition by measuring the decay in the similarity among pairs of communities along spatial or environmental distances. We provide the first global synthesis of taxonomic and functional distance decay along spatial and environmental distance by analysing 149 datasets comprising different types of organisms and environments. We modelled an exponential distance decay for each dataset using generalized linear models and extracted r2 and slope to analyse the strength and the rate of the decay. We studied whether taxonomic or functional similarity has stronger decay across the spatial and environmental distances. We also unveiled the factors driving the rate of decay across the datasets, including latitude, spatial extent, realm, and organismal features. Taxonomic distance decay was stronger along spatial and environmental distances compared with functional distance decay. The rate of taxonomic spatial distance decay was the fastest in the datasets from mid-latitudes while the rate of functional decay increased with latitude. Overall, datasets covering larger spatial extents showed a lower rate of decay along spatial distances but a higher rate of decay along environmental distances. Marine ecosystems had the slowest rate of decay. This synthesis is an important step towards a more holistic understanding of patterns and drivers of taxonomic and functional β-diversity.

scholarly journals Theoretical guidelines for editing ecological communities

2020 ◽  
Author(s):  
Vu Nguyen ◽  
Dervis Can Vural
Keyword(s):  
Community Resilience ◽  
Optimization Process ◽  
Community Control ◽  
Ecological Communities ◽  
Interspecies Interactions ◽  
Cost Parameter ◽  
Pairwise Interactions ◽  
Species Abundances

Having control over species abundances and community resilience is of great interest for experimental, agricultural, industrial and conservational purposes. Here, we theoretically explore the possibility of manipulating ecological communities by modifying pairwise interactions. Specifically, we establish which interaction values should be modified, and by how much, in order to alter the composition or resilience of a community towards a favorable direction. While doing so, we also take into account the experimental difficulties in making such modifications by including in our optimization process, a cost parameter, which penalizes large modifications. In addition to prescribing what changes should be made to interspecies interactions given some modification cost, our approach also serves to establish the limits of community control, i.e. how well can one approach an ecological goal at best, even when not constrained by cost.

The impact of population structure on population and community dynamics

2020 ◽  
pp. 53-73
Author(s):  
André M. de Roos
Keyword(s):  
Life History ◽  
Community Dynamics ◽  
Human Impacts ◽  
Population Models ◽  
Ecological Communities ◽  
Structured Population Models ◽  
Structured Population ◽  
Species Abundances ◽  
Population And Community Dynamics ◽  
The Individual

Ecological theory about dynamics of interacting species constitutes the basis for our understanding of the functioning of ecological communities and ecosystems and their responses to changing environmental conditions, natural disturbances, and human impacts. The mathematical foundation of this theory emphasizes changes in species abundances only, ignoring those aspects that make biological organisms unique, in particular within-population variation due to individual development during life history and individual energetics. In contrast, structured population models do take these aspects into account and hence explicitly link individual life history to population dynamics. In this chapter, I review the different types of structured population models and which purposes they are especially suited for. I will subsequently focus on physiologically structured population models (PSPMs), which are especially suited to model the interactions within and between populations. I will review the key ecological insights that have been derived using PSPMs and show how and why predictions by PSPMs often contrast with the basic rules-of-thumb that make up classical theory based on unstructured models. Finally, I will discuss the experimental and empirical evidence for the counter-intuitive predictions by PSPMs, emphasizing that PSPMs allow for testing at both the individual and population level and hence for a tight link between theory and data.

scholarly journals Temporal turnover and the maintenance of diversity in ecological assemblages

2010 ◽  
Vol 365 (1558) ◽  
pp. 3611-3620 ◽  
Author(s):  
Anne E. Magurran ◽  
Peter A. Henderson
Keyword(s):  
Time Series ◽  
Assemblage Structure ◽  
Individual Species ◽  
Ecological Communities ◽  
Time Series Modelling ◽  
Species Abundances ◽  
Temporal Turnover ◽  
The Individual ◽  
And Function ◽  
Modelling Approach

Temporal variation in species abundances occurs in all ecological communities. Here, we explore the role that this temporal turnover plays in maintaining assemblage diversity. We investigate a three-decade time series of estuarine fishes and show that the abundances of the individual species fluctuate asynchronously around their mean levels. We then use a time-series modelling approach to examine the consequences of different patterns of turnover, by asking how the correlation between the abundance of a species in a given year and its abundance in the previous year influences the structure of the overall assemblage. Classical diversity measures that ignore species identities reveal that the observed assemblage structure will persist under all but the most extreme conditions. However, metrics that track species identities indicate a narrower set of turnover scenarios under which the predicted assemblage resembles the natural one. Our study suggests that species diversity metrics are insensitive to change and that measures that track species ranks may provide better early warning that an assemblage is being perturbed. It also highlights the need to incorporate temporal turnover in investigations of assemblage structure and function.

scholarly journals Emergence of structural and dynamical properties of ecological mutualistic networks

2014 ◽  
Author(s):  
Samir Suweis ◽  
Filippo Simini ◽  
Jayanth Banavar ◽  
Amos Maritan
Keyword(s):  
Species Abundance ◽  
Interaction Matrix ◽  
Ecological Communities ◽  
Generalist Species ◽  
Mutualistic Interactions ◽  
Species Abundances ◽  
Dynamical Properties ◽  
Mutualistic Networks ◽  
Specialist Species ◽  
The Many

Mutualistic networks are formed when the interactions between two classes of species are mutually beneficial. They are important examples of cooperation shaped by evolution. Mutualism between animals and plants has a key role in the organization of ecological communities. Such networks in ecology have generally evolved a nested architecture independent of species composition and latitude; specialist species, with only few mutualistic links, tend to interact with a proper subset of the many mutualistic partners of any of the generalist species. Despite sustained efforts to explain observed network structure on the basis of community-level stability or persistence, such correlative studies have reached minimal consensus. Here we show that nested interaction networks could emerge as a consequence of an optimization principle aimed atmaximizing the species abundance in mutualistic communities. Using analytical and numerical approaches, we show that because of the mutualistic interactions, an increase in abundance of a given species results in a corresponding increase in the total number of individuals in the community, and also an increase in the nestedness of the interaction matrix. Indeed, the species abundances and the nestedness of the interaction matrix are correlated by a factor that depends on the strength of the mutualistic interactions. Nestedness and the observed spontaneous emergence of generalist and specialist species occur for several dynamical implementations of the variational principle under stationary conditions. Optimized networks, although remaining stable, tend to be less resilient than their counterparts with randomly assigned interactions. In particular, we show analytically that the abundance of the rarest species is linked directly to the resilience of the community. Our work provides a unifying framework for studying the emergent structural and dynamical properties of ecological mutualistic networks.

scholarly journals Competitive dominance in plant communities: Modeling approaches and theoretical predictions

2020 ◽  
Author(s):  
José A. Capitán ◽  
Sara Cuenda ◽  
David Alonso
Keyword(s):  
Species Coexistence ◽  
Markov Models ◽  
Spatial Scales ◽  
Spatially Explicit ◽  
Ecological Communities ◽  
Natural Ecosystems ◽  
Theoretical Predictions ◽  
Species Abundances ◽  
Active Research ◽  
Clustering Patterns

AbstractQuantitative predictions about the processes that promote species coexistence are a subject of active research in ecology. In particular, competitive interactions are known to shape and maintain ecological communities, and situations where some species out-compete or dominate over some others are key to describe natural ecosystems. Here we develop ecological theory using a stochastic, synthetic framework for plant community assembly that leads to predictions amenable to empirical testing. We propose two stochastic continuous-time Markov models that incorporate competitive dominance through a hierarchy of species heights. The first model, which is spatially implicit, predicts both the expected number of species that survive and the conditions under which heights are clustered in realized model communities. The second one allows spatially-explicit interactions of individuals and alternative mechanisms that can help shorter plants overcome height-driven competition, and it demonstrates that clustering patterns remain not only locally but also across increasing spatial scales. Moreover, although plants are actually height-clustered in the spatially-explicit model, it allows for plant species abundances not necessarily skewed to taller plants.

scholarly journals Physiology underlies the assembly of ecological communities

2018 ◽  
Vol 115 (23) ◽  
pp. 6016-6021 ◽  
Author(s):  
Denon Start ◽  
Shannon McCauley ◽  
Benjamin Gilbert
Keyword(s):  
Community Composition ◽  
Species Distributions ◽  
Phenotypic Selection ◽  
Ecological Communities ◽  
Causal Relationships ◽  
Physiological Mechanisms ◽  
Behavioral Traits ◽  
Top Predators ◽  
Species Abundances ◽  
Opposing Effects

Trait-based community ecology promises an understanding of the factors that determine species abundances and distributions across habitats. However, ecologists are often faced with large suites of potentially important traits, making generalizations across ecosystems and species difficult or even impossible. Here, we hypothesize that key traits structuring ecological communities may be causally dependent on common physiological mechanisms and that elucidating these mechanisms can help us understand the distributions of traits and species across habitats. We test this hypothesis by investigating putatively causal relationships between physiological and behavioral traits at the species and community levels in larvae of 17 species of dragonfly that co-occur at the landscape scale but segregate among lakes. We use tools borrowed from phenotypic selection analyses to show that physiological traits underlie activity rate, which has opposing effects on foraging and predator avoidance behaviors. The effect of activity on these behaviors ultimately shapes species distributions and community composition in habitats with either large-bodied fish or invertebrates as top predators. Remarkably, despite the inherent complexity of ecological communities, the expression of just two biomolecules accounts for a high proportion of the variation in behavioral traits and hence, dragonfly community composition between habitats. We suggest that causal relationships among traits can drive species distributions and community assembly.

scholarly journals Feasibility and coexistence of large ecological communities

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Jacopo Grilli ◽  
Matteo Adorisio ◽  
Samir Suweis ◽  
György Barabás ◽  
Jayanth R. Banavar ◽  
...  
Keyword(s):  
Asymptotic Stability ◽  
Species Interactions ◽  
Ecological Communities ◽  
Ecological Network ◽  
Small Perturbations ◽  
Local Asymptotic Stability ◽  
Species Abundances ◽  
The Stability ◽  
Empirical Networks

Abstract The role of species interactions in controlling the interplay between the stability of ecosystems and their biodiversity is still not well understood. The ability of ecological communities to recover after small perturbations of the species abundances (local asymptotic stability) has been well studied, whereas the likelihood of a community to persist when the conditions change (structural stability) has received much less attention. Our goal is to understand the effects of diversity, interaction strengths and ecological network structure on the volume of parameter space leading to feasible equilibria. We develop a geometrical framework to study the range of conditions necessary for feasible coexistence. We show that feasibility is determined by few quantities describing the interactions, yielding a nontrivial complexity–feasibility relationship. Analysing more than 100 empirical networks, we show that the range of coexistence conditions in mutualistic systems can be analytically predicted. Finally, we characterize the geometric shape of the feasibility domain, thereby identifying the direction of perturbations that are more likely to cause extinctions.

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