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

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.

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Vulnerable species interactions are important for the stability of mutualistic networks

10.1101/604868 ◽

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.

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Effect of Localization on the Stability of Mutualistic Ecological Networks

10.1101/023275 ◽

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.

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Real-world Interaction Networks Buffer Impact of Small Evolutionary Shifts On Biodiversity

10.1101/013086 ◽

2014 ◽

Author(s):

Gabriel E Leventhal ◽

Liyu Wang ◽

Roger D Kouyos

Keyword(s):

Real World ◽

Environmental Changes ◽

Interaction Network ◽

Species Interaction ◽

Interaction Networks ◽

Community Diversity ◽

Ecological Communities ◽

Interaction Structure ◽

Evolutionary Changes ◽

Biodiversity Maintenance

Biodiversity maintenance and community evolution depend on the species interaction network. The "diversity-stability debate" has revealed that the complex interaction structure within real-world ecosystems determines how ecological communities respond to environmental changes, but can have opposite effects depending on the community type. Here we quantify the influence of shifts on community diversity and stability at both the species level and the community level. We use interaction networks from 19 real-world mutualistic communities and simulate shifts to antagonism. We demonstrate that both the placement of the shifting species in the community, as well as the structure of the interaction network as a whole contribute to stability and diversity maintenance under shifts. Our results suggest that the interaction structure of natural communities generally enhances community robustness against small ecological and evolutionary changes, but exacerbates the consequences of large changes.

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Heterozygous Trees Rebound the Fastest after Felling by Beavers to Positively Affect Arthropod Community Diversity

Forests ◽

10.3390/f12060694 ◽

2021 ◽

Vol 12 (6) ◽

pp. 694

Author(s):

Faith M. Walker ◽

Rachel Durben ◽

Stephen M. Shuster ◽

Richard L. Lindroth ◽

Thomas G. Whitham

Keyword(s):

Genetic Diversity ◽

Genetic Relatedness ◽

Castor Canadensis ◽

High Stress ◽

Underlying Mechanism ◽

Community Level ◽

Community Diversity ◽

Population Substructure ◽

Individual Plant ◽

Arthropod Community

Although genetic diversity within stands of trees is known to have community-level consequences, whether such effects are present at an even finer genetic scale is unknown. We examined the hypothesis that genetic variability (heterozygosity) within an individual plant would affect its dependent community, which adds a new dimension to the importance of genetic diversity. Our study contrasted foliar arthropod community diversity and microsatellite marker-derived measures of genetic diversity of cottonwood (Populus fremontii) trees that had been felled by beavers (Castor canadensis) and were resprouting, relative to adjacent standing, unfelled trees. Three patterns emerged: 1. Productivity (specific leaf area), phytochemical defenses (salicortin), and arthropod community richness, abundance, and diversity were positively correlated with the heterozygosity of individual felled trees, but not with that of unfelled trees; 2. These relationships were not explained by population substructure, genetic relatedness of the trees, or hybridization; 3. The underlying mechanism appears to be that beaver herbivory stimulates increased productivity (i.e., 2× increase from the most homozygous to the most heterozygous tree) that is the greatest in more heterozygous trees. Salicortin defenses in twigs were also expressed at higher concentrations in more heterozygous trees (i.e., 3× increase from the most homozygous to the most heterozygous tree), which suggests that this compound may dissuade further herbivory by beavers, as has been found for other mammalian herbivores. We suggest that high stress to trees as a consequence of felling reveals a heterozygosity–productivity linkage, which in turn is attractive to arthropods. Although experiments are required to demonstrate causality, these results link the genetic diversity of individual trees to community diversity, supporting the hypothesis that interactions among foundation species (beavers and trees) have community-level effects, and underscores the importance of genetic diversity for biodiversity, conservation, and restoration.

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Dissimilarity of species interaction networks: how to partition rewiring and species turnover components

Ecosphere ◽

10.1002/ecs2.3653 ◽

2021 ◽

Vol 12 (7) ◽

Author(s):

Jochen Fründ

Keyword(s):

Species Turnover ◽

Species Interaction ◽

Interaction Networks

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Mutualistic strategies minimize coextinction in plant–disperser networks

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2016.2302 ◽

2017 ◽

Vol 284 (1854) ◽

pp. 20162302 ◽

Cited By ~ 15

Author(s):

Evan C. Fricke ◽

Joshua J. Tewksbury ◽

Elizabeth M. Wandrag ◽

Haldre S. Rogers

Keyword(s):

Network Structure ◽

Field Experiments ◽

Empirical Relationship ◽

Network Models ◽

Mutualistic Interactions ◽

Simulated Network ◽

Direct And Indirect Impacts ◽

Indirect Impacts ◽

The Stability ◽

Seed Dispersal Mutualism

The global decline of mutualists such as pollinators and seed dispersers may cause negative direct and indirect impacts on biodiversity. Mutualistic network models used to understand the stability of mutualistic systems indicate that species with low partner diversity are most vulnerable to coextinction following mutualism disruption. However, existing models have not considered how species vary in their dependence on mutualistic interactions for reproduction or survival, overlooking the potential influence of this variation on species' coextinction vulnerability and on network stability. Using global databases and field experiments focused on the seed dispersal mutualism, we found that plants and animals that depend heavily on mutualistic interactions have higher partner diversity. Under simulated network disruption, this empirical relationship strongly reduced coextinction because the species most likely to lose mutualists depend least on their mutualists. The pattern also reduced the importance of network structure for stability; nested network structure had little effect on coextinction after simulations incorporated the empirically derived relationship between partner diversity and mutualistic dependence. Our results highlight a previously unknown source of stability in mutualistic networks and suggest that differences among species in their mutualistic strategy, rather than network structure, primarily accounts for stability in mutualistic communities.

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Does genomic variation in a foundation species predict arthropod community structure in a riparian forest?

Molecular Ecology ◽

10.1111/mec.14515 ◽

2018 ◽

Vol 27 (5) ◽

pp. 1284-1295 ◽

Cited By ~ 9

Author(s):

Shinnosuke Kagiya ◽

Masaki Yasugi ◽

Hiroshi Kudoh ◽

Atsushi J. Nagano ◽

Shunsuke Utsumi

Keyword(s):

Community Structure ◽

Riparian Forest ◽

Genomic Variation ◽

Foundation Species ◽

Arthropod Community

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Ribulose 1,5-bisphosphate carboxylase. Effect on the catalytic properties of changing methionine-330 to leucine in the Rhodospirillum rubrum enzyme

Biochemical Journal ◽

10.1042/bj2350839 ◽

1986 ◽

Vol 235 (3) ◽

pp. 839-846 ◽

Cited By ~ 30

Author(s):

B E Terzaghi ◽

W A Laing ◽

J T Christeller ◽

G B Petersen ◽

D F Hill

Keyword(s):

Rhodospirillum Rubrum ◽

Oligonucleotide Primer ◽

Similar Amount ◽

Ribulose Bisphosphate Carboxylase ◽

Ribulose Bisphosphate ◽

Carboxylase Activity ◽

Bisphosphate Carboxylase ◽

Ribulose Bisphosphate Carboxylase Oxygenase ◽

In The Wild ◽

The Stability

Oligonucleotide-directed mutagenesis of cloned Rhodospirillum rubrum ribulose bisphosphate carboxylase/oxygenase with a synthetic 13mer oligonucleotide primer was used to effect a change at Met-330 to Leu-330. The resultant enzyme was kinetically examined in some detail and the following changes were found. The Km(CO2) increased from 0.16 to 2.35 mM, the Km(ribulose bisphosphate) increased from 0.05 to 1.40 mM for the carboxylase reaction and by a similar amount for the oxygenase reaction. The Ki(O2) increased from 0.17 to 6.00 mM, but the ratio of carboxylase activity to oxygenase activity was scarcely affected by the change in amino acid. The binding of the transition state analogue 2-carboxyribitol 1,5-bisphosphate was reversible in the mutant and essentially irreversible in the wild type enzyme. Inhibition by fructose bisphosphate, competitive with ribulose bisphosphate, was slightly increased in the mutant enzyme. These data suggest that the change of the residue from methionine to leucine decreases the stability of the enediol reaction intermediate.

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

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2023709118 ◽

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.

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