scholarly journals Evolutionary responses to conditionality in species interactions across environmental gradients

2015 ◽  
Author(s):  
Anna M. O’Brien ◽  
Ruairidh J.H. Sawers ◽  
Jeffrey Ross-Ibarra ◽  
Sharon Y. Strauss
Keyword(s):  
Statistical Models ◽  
Species Interactions ◽  
Environmental Gradients ◽  
Niche Partitioning ◽  
Character Displacement ◽  
Arms Race ◽  
Positive Interactions ◽  
Common Pattern ◽  
Interacting Species ◽  
Stressful Environments

AbstractThe outcomes of many species interactions are conditional on the environments in which they occur. A common pattern is that outcomes grade from being more positive under stressful conditions to more antagonistic or neutral under benign conditions. The evolutionary implications of conditionality in interactions have received much less attention than the documentation of conditionality itself, with a few notable exceptions. Here, we predict patterns of adaptation and co-adaptation between partners along abiotic gradients, positing that when interactions become more positive in stressful environments, fitness outcomes for mutations affecting interactions align across partners and selection should favor greater mutualistic adap-tation and co-adaptation between interacting species. As a corollary, in benign environments, if interactions are strongly antagonistic, we predict antagonistic co-adaptation resulting in Red Queen or arms-race dynamics, or reduction of antagonism through character displacement and niche partitioning. We predict no adaptation if interactions are more neutral. We call this the CoCoA hypothesis: (Co)-adaptation and Conditionality across Abiotic gradients. We describe experimental designs and statistical models that allow testing predictions of CoCoA, with a focus on positive interactions. While only one study has included all the elements to test CoCoA, we briefly review the literature and summarize study findings relevant to CoCoA and highlight opportunities to test CoCoA further.

scholarly journals Niche partitioning of microbial communities in riverine floodplains

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Marc Peipoch ◽  
Scott R. Miller ◽  
Tiago R. Antao ◽  
H. Maurice Valett
Keyword(s):  
Microbial Communities ◽  
Species Interactions ◽  
Large Scale ◽  
Environmental Gradients ◽  
Niche Partitioning ◽  
Habitat Diversity ◽  
Positive Interactions ◽  
Species Sorting ◽  
Flow Alteration ◽  
Faunal Diversity

Abstract Riverine floodplains exhibit high floral and faunal diversity as a consequence of their biophysical complexity. Extension of such niche partitioning processes to microbial communities is far less resolved or supported. Here, we evaluated the responses of aquatic biofilms diversity to environmental gradients across ten riverine floodplains with differing degrees of flow alteration and habitat diversity to assess whether complex floodplains support biofilm communities with greater biodiversity and species interactions. No significant evidence was found to support a central role for habitat diversity in promoting microbial diversity across 116 samples derived from 62 aquatic habitats, as neither α (H’: 2.8–4.1) nor β (Sørensen: 0.3–0.39) diversity were positively related to floodplain complexity across the ten floodplains. In contrast, our results documented the sensitivity of biofilm communities to regional templates manifested as gradients of carbon, nitrogen, and phosphorous availability. Large-scale conditions reflecting nitrogen limitation increased the relative abundance of N-fixing cyanobacteria (up to 0.34 as fraction of total reads), constrained the total number of interactions among bacterial taxa, and reinforced negative over positive interactions, generating unique microbial communities and networks that reflect large-scale species sorting in response to regional geochemical gradients.

Facilitation and the Organization of Communities

Ecology ◽  
2012 ◽  
Author(s):  
Christopher J. Lortie
Keyword(s):  
Species Interactions ◽  
Environmental Gradients ◽  
Plant Competition ◽  
Historical Background ◽  
Positive Interactions ◽  
Plant Interactions ◽  
Reciprocal Effect ◽  
Early 21St Century ◽  
Analytical Approaches ◽  
Plant Plant

Species interactions are a cornerstone of ecological research wherein the effects of an individual of one species on another individual, frequently a different species, are studied. Within versus between species interactions are also commonly contrasted as a means to infer relative importance, but the majority of theory advances, at least at the community level, are associated with interactions between individuals of different species. Interactions can range from positive to negative, and effects are measured at all levels of development, or life history stages, of an organism. Positive interactions have been extensively studied in both population and community ecology. Facilitation, however, is a relatively specific term that has evolved primarily to describe positive plant–plant interactions (see Defining Facilitation). Facilitation, or positive interactions, is a relatively recent subset of these species interactions in general, including related processes, such as competition, mutualism, and parasitism. Facilitation is best viewed as the antithesis of the plant competition literature, as it shares many of the main attributes, both in terms of scope and approach, and arose as a comparator to this research. Facilitation studies mainly refer to positive plant–plant interactions, as the term was proposed in the plant literature and extensively used to describe interactions that include a positive effect of one species on another. Mutualism and parasitism research is often plant–insect based and formally identifies the reciprocal effect in the interaction, that is, (+, +) in mutualism and (+,−) in parasitism, whereas facilitation studies are generally (+,0) or (+,?), with the second effect often unreported. Interactions that include at least one negative interaction are usually described as competition in the plant literature and do not apply the term facilitation (although the frequency of both being discussed concomitantly is increasing). Hence, the term facilitation, owing to historical use, describes the subset of interactions that are (+,0) and is mostly specific to within plants, although its usage is expanding. The research on facilitation has most likely peaked, similar to plant competition studies, in that facilitation has been clearly established as an important process in the formation of plant communities. Additional studies simply demonstrating facilitation are increasing unlikely to be present in the literature. That said, the implications to theory and other, more nuanced aspects of interaction, such as context dependence, shifting balances, and importance of the environment, as they relate to facilitation, are still largely unexplored. In the early 21st century the most contentious debates, with respect to facilitation, center on either disagreement concerning what a community is and whether research should be conducted at this scale or on how to use environmental gradients (i.e., stress) most effectively. Both of these topics are described herein, with readings also included on Historical Background, Experimental and Analytical Approaches, Evolution, other taxa, and Applications.

scholarly journals Counteracting Forces of Introgressive Hybridization and Interspecific Competition Shape the Morphological Traits of Cryptic Lberian Eptesicus Bats

2021 ◽  
Author(s):  
Pedro Horta ◽  
Helena Raposeira ◽  
Adrián Baños ◽  
Carlos Ibáñez ◽  
Orly Razgour ◽  
...  
Keyword(s):  
Interspecific Competition ◽  
Species Interactions ◽  
Morphological Traits ◽  
Prey Availability ◽  
Niche Partitioning ◽  
Introgressive Hybridization ◽  
Character Displacement ◽  
Wing Morphology ◽  
Adaptive Introgression ◽  
Evolutionary Forces

Abstract Cryptic species that coexist in sympatry are likely to simultaneously experience strong competition and hybridization. The first phenomenon would lead to character displacement, whereas the second can potentially promote morphological similarity through adaptive introgression. The main goal of this work was to investigate the effect of introgressive hybridization on the morphology of cryptic Iberian Eptesicus bats when facing counteracting evolutionary forces from interspecific competition. We found substantial overlap both in dentition and in wing morphology traits, though mainly in individuals in sympatry. The presence of hybrids contributes to a fifth of this overlap, with hybrids showing traits with intermediate morphometry. Thus, introgressive hybridization may contribute to species adaptation to trophic and ecological space responding directly to the macro-habitats characteristics of the sympatric zone and to local prey availability. On the other hand, fur shade tended to be browner and brighter in hybrids than parental species. Colour differences could result from partitioning of resources as an adaptation to environmental factors such as roost and microhabitats. We argue that a balance between adaptive introgression and niche partitioning shapes species interactions with the environment through affecting morphological traits under selection.

scholarly journals Sensory-based niche partitioning in a multiple predator–multiple prey community

2015 ◽  
Vol 282 (1808) ◽  
pp. 20150520 ◽  
Author(s):  
Jay J. Falk ◽  
Hannah M. ter Hofstede ◽  
Patricia L. Jones ◽  
Marjorie M. Dixon ◽  
Paul A. Faure ◽  
...  
Keyword(s):  
Species Interactions ◽  
Prey Species ◽  
Niche Partitioning ◽  
Signal Evolution ◽  
Signal Design ◽  
Predator Species ◽  
Mate Attraction ◽  
Communication Signals ◽  
Signal Features ◽  
The Impact

Many predators and parasites eavesdrop on the communication signals of their prey. Eavesdropping is typically studied as dyadic predator–prey species interactions; yet in nature, most predators target multiple prey species and most prey must evade multiple predator species. The impact of predator communities on prey signal evolution is not well understood. Predators could converge in their preferences for conspicuous signal properties, generating competition among predators and natural selection on particular prey signal features. Alternatively, predator species could vary in their preferences for prey signal properties, resulting in sensory-based niche partitioning of prey resources. In the Neotropics, many substrate-gleaning bats use the mate-attraction songs of male katydids to locate them as prey. We studied mechanisms of niche partitioning in four substrate-gleaning bat species and found they are similar in morphology, echolocation signal design and prey-handling ability, but each species preferred different acoustic features of male song in 12 sympatric katydid species. This divergence in predator preference probably contributes to the coexistence of many substrate-gleaning bat species in the Neotropics, and the substantial diversity in the mate-attraction signals of katydids. Our results provide insight into how multiple eavesdropping predator species might influence prey signal evolution through sensory-based niche partitioning.

scholarly journals Evolutionary Responses to Conditionality in Species Interactions across Environmental Gradients

2018 ◽  
Vol 192 (6) ◽  
pp. 715-730 ◽  
Author(s):  
Anna M. O’Brien ◽  
Ruairidh J. H. Sawers ◽  
Jeffrey Ross-Ibarra ◽  
Sharon Y. Strauss
Keyword(s):  
Species Interactions ◽  
Environmental Gradients

scholarly journals The geographic mosaic of coevolution in mutualistic networks

2018 ◽  
Vol 115 (47) ◽  
pp. 12017-12022 ◽  
Author(s):  
Lucas P. Medeiros ◽  
Guilherme Garcia ◽  
John N. Thompson ◽  
Paulo R. Guimarães
Keyword(s):  
Gene Flow ◽  
Species Interactions ◽  
Analytical Approximation ◽  
Spatial Processes ◽  
Geographic Mosaic ◽  
Generalist Species ◽  
Interacting Species ◽  
Adaptive Landscapes ◽  
Surprising Effect ◽  
Mutualistic Networks

Ecological interactions shape adaptations through coevolution not only between pairs of species but also through entire multispecies assemblages. Local coevolution can then be further altered through spatial processes that have been formally partitioned in the geographic mosaic theory of coevolution. A major current challenge is to understand the spatial patterns of coadaptation that emerge across ecosystems through the interplay between gene flow and selection in networks of interacting species. Here, we combine a coevolutionary model, network theory, and empirical information on species interactions to investigate how gene flow and geographical variation in selection affect trait patterns in mutualistic networks. We show that gene flow has the surprising effect of favoring trait matching, especially among generalist species in species-rich networks typical of pollination and seed dispersal interactions. Using an analytical approximation of our model, we demonstrate that gene flow promotes trait matching by making the adaptive landscapes of different species more similar to each other. We use this result to show that the progressive loss of gene flow associated with habitat fragmentation may undermine coadaptation in mutualisms. Our results therefore provide predictions of how spatial processes shape the evolution of species-rich interactions and how the widespread fragmentation of natural landscapes may modify the coevolutionary process.

scholarly journals Facilitation costs and benefits function simultaneously on stress gradients for animals

2018 ◽  
Vol 285 (1885) ◽  
pp. 20180983 ◽  
Author(s):  
Olivier Dangles ◽  
Mario Herrera ◽  
Carlos Carpio ◽  
Christopher J. Lortie
Keyword(s):  
Conceptual Framework ◽  
Environmental Conditions ◽  
Species Interactions ◽  
Stress Gradient ◽  
Species Interaction ◽  
Positive Interactions ◽  
Costs And Benefits ◽  
Strong Basis ◽  
Stress Gradients ◽  
High Resource

Understanding the variation in species interactions along environmental stress gradients is crucial for making robust ecological predictions about community responses to changing environmental conditions. The facilitation–competition framework has provided a strong basis for predictions (e.g. the stress-gradient hypothesis, SGH), yet the mechanisms behind patterns in animal interactions on stress gradients are poorly explored in particular for mobile animals. Here, we proposed a conceptual framework modelling changes in facilitation costs and benefits along stress gradients and experimentally tested this framework by measuring fitness outcomes of benefactor–beneficiary interactions across resource quality levels. Three arthropod consumer models from a broad array of environmental conditions were used including aquatic detritivores, potato moths and rainforest carrion beetles. We detected a shift to more positive interactions at increasing levels of stress thereby supporting the application of the SGH to mobile animals. While most benefactors paid no significant cost of facilitation, an increase in potato moth beneficiary's growth at high resource stress triggered costs for benefactors. This study is the first to experimentally show that both costs and benefits function simultaneously on stress gradients for animals. The proposed conceptual framework could guide future studies examining species interaction outcomes for both animals and plants in an increasingly stressed world.

scholarly journals A sparse observation model to quantify species interactions in time and space

2019 ◽  
Author(s):  
Sadoune Ait Kaci Azzou ◽  
Liam Singer ◽  
Thierry Aebischer ◽  
Madleina Caduff ◽  
Beat Wolf ◽  
...  
Keyword(s):  
Species Interactions ◽  
Activity Patterns ◽  
Niche Partitioning ◽  
Camera Trap ◽  
Camera Traps ◽  
Observation Model ◽  
Occupancy Models ◽  
Time And Space ◽  
Imperfect Detection ◽  
Mobile Species

SummaryCamera traps and acoustic recording devices are essential tools to quantify the distribution, abundance and behavior of mobile species. Varying detection probabilities among device locations must be accounted for when analyzing such data, which is generally done using occupancy models. We introduce a Bayesian Time-dependent Observation Model for Camera Trap data (Tomcat), suited to estimate relative event densities in space and time. Tomcat allows to learn about the environmental requirements and daily activity patterns of species while accounting for imperfect detection. It further implements a sparse model that deals well will a large number of potentially highly correlated environmental variables. By integrating both spatial and temporal information, we extend the notation of overlap coefficient between species to time and space to study niche partitioning. We illustrate the power of Tomcat through an application to camera trap data of eight sympatrically occurring duiker Cephalophinae species in the savanna - rainforest ecotone in the Central African Republic and show that most species pairs show little overlap. Exceptions are those for which one species is very rare, likely as a result of direct competition.

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