Plantago spp. as models for studying the ecology and evolution of species interactions across environmental gradients

2021 ◽  
Author(s):  
Rachel Michael Penczykowski ◽  
R. Drew Sieg
Keyword(s):  
Species Interactions ◽  
Environmental Gradients

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 emergent interactions that govern biodiversity change

2020 ◽  
Vol 117 (29) ◽  
pp. 17074-17083 ◽  
Author(s):  
James S. Clark ◽  
C. Lane Scher ◽  
Margaret Swift
Keyword(s):  
Species Interactions ◽  
Environmental Gradients ◽  
Local Population ◽  
Species Abundance ◽  
Community Change ◽  
Model Specification ◽  
Data Simulation ◽  
Breeding Bird ◽  
Probabilistic Uncertainty ◽  
Nonlinear Responses

Observational studies have not yet shown that environmental variables can explain pervasive nonlinear patterns of species abundance, because those patterns could result from (indirect) interactions with other species (e.g., competition), and models only estimate direct responses. The experiments that could extract these indirect effects at regional to continental scales are not feasible. Here, a biophysical approach quantifies environment– species interactions (ESI) that govern community change from field data. Just as species interactions depend on population abundances, so too do the effects of environment, as when drought is amplified by competition. By embedding dynamic ESI within framework that admits data gathered on different scales, we quantify responses that are induced indirectly through other species, including probabilistic uncertainty in parameters, model specification, and data. Simulation demonstrates that ESI are needed for accurate interpretation. Analysis demonstrates how nonlinear responses arise even when their direct responses to environment are linear. Applications to experimental lakes and the Breeding Bird Survey (BBS) yield contrasting estimates of ESI. In closed lakes, interactions involving phytoplankton and their zooplankton grazers play a large role. By contrast, ESI are weak in BBS, as expected where year-to-year movement degrades the link between local population growth and species interactions. In both cases, nonlinear responses to environmental gradients are induced by interactions between species. Stability analysis indicates stability in the closed-system lakes and instability in BBS. The probabilistic framework has direct application to conservation planning that must weigh risk assessments for entire habitats and communities against competing interests.

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.

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 A common framework for identifying linkage rules across different types of interactions

2015 ◽  
Author(s):  
Ignasi Bartomeus ◽  
Dominique Gravel ◽  
Jason Tylianakis ◽  
Marcelo Aizen ◽  
Ian Dickie ◽  
...  
Keyword(s):  
Ecosystem Functioning ◽  
Species Interactions ◽  
Community Dynamics ◽  
Developmental Stages ◽  
Environmental Gradients ◽  
Interspecific Interactions ◽  
General Structure ◽  
Species Traits ◽  
Ecological Processes ◽  
Wrong Reason

Species interactions, ranging from antagonisms to mutualisms, form the architecture of biodiversity and determine ecosystem functioning. Understanding the rules responsible for who interacts with whom, as well as the functional consequences of these interspecific interactions, is central to predicting community dynamics and stability. Species traitssensu latomay affect different ecological processes determining species interactions through a two-step process. First, ecological and life-history traits govern species distributions and abundance, and hence determine species co-occurrence, which is a prerequisite for them to interact. Second, morphological traits between co-occurring potential interaction partners should match for the realization of an interaction. Moreover, inferring functioning from a network of interactions may require the incorporation of interaction efficiency. This efficiency may be also trait-mediated, and can depend on the extent of matching, or on morphological, physiological or behavioural traits. It has been shown that both neutral and trait-based models can predict the general structure of networks, but they rarely accurately predict individual interactions, suggesting that these models may be predicting the right structure for the wrong reason. We propose to move away from testing null models with a framework that explicitly models the probability of interaction among individuals given their traits. The proposed models integrate both neutral and trait-matching constraints while using only information about known interactions, thereby overcoming problems originating from under-sampling of rare interactions (i.e. missing links). They can easily accommodate qualitative or quantitative data, and can incorporate trait variation within species, such as values that vary along developmental stages or environmental gradients. We use three case studies to show that they can detect strong trait matching (e.g. predator-prey system), relaxed trait matching (e.g. herbivore-plant system) and barrier trait matching (e.g. plant-pollinator systems). Only by elucidating which species traits are important in each process, i.e. in determining interaction establishment, frequency, and efficiency, can we advance in explaining how species interact and the consequences for ecosystem functioning.

scholarly journals Spatial variation in species' roles in host–helminth networks

2021 ◽  
Vol 376 (1837) ◽  
pp. 20200361 ◽  
Author(s):  
Tad A. Dallas ◽  
Pedro Jordano
Keyword(s):  
Species Interactions ◽  
Parasite Species ◽  
Environmental Gradients ◽  
Dimensional Space ◽  
Single Species ◽  
Parasite Community ◽  
Helminth Parasite ◽  
Helminth Parasites ◽  
Two Dimensional ◽  
Species Roles

Species interactions may vary considerably across space as a result of spatial and environmental gradients. With respect to host–parasite interactions, this suggests that host and parasite species may play different functional roles across the different networks they occur in. Using a global occurrence database of helminth parasites, we examine the conservation of species' roles using data on host–helminth interactions from 299 geopolitical locations. Defining species' roles in a two-dimensional space which captures the tendency of species to be more densely linked within species subgroups than between subgroups, we quantified species' roles in two ways, which captured if and which species' roles are conserved by treating species' utilization of this two-dimensional space as continuous, while also classifying species into categorical roles. Both approaches failed to detect the conservation of species' roles for a single species out of over 38 000 host and helminth parasite species. Together, our findings suggest that species' roles in host–helminth networks may not be conserved, pointing to the potential role of spatial and environmental gradients, as well as the importance of the context of the local host and helminth parasite community. This article is part of the theme issue ‘Infectious disease macroecology: parasite diversity and dynamics across the globe’.

scholarly journals Species interactions, environmental gradients and body size shape population niche width

2021 ◽  
Author(s):  
Antti P. Eloranta ◽  
Anders G. Finstad ◽  
Odd Terje Sandlund ◽  
Rune Knudsen ◽  
Anna Kuparinen ◽  
...  
Keyword(s):  
Body Size ◽  
Species Interactions ◽  
Environmental Gradients ◽  
Niche Width

scholarly journals Hypotheses to explain the origin of species in Amazonia

2008 ◽  
Vol 68 (4 suppl) ◽  
pp. 917-947 ◽  
Author(s):  
J. Haffer
Keyword(s):  
Species Interactions ◽  
Environmental Gradients ◽  
Milankovitch Cycles ◽  
Barrier Effect ◽  
Climatic Fluctuations ◽  
Canopy Density ◽  
Sea Level Fluctuations ◽  
Animal Populations ◽  
Barrier Formation ◽  
Parapatric Speciation

The main hypotheses proposed to explain barrier formation separating populations and causing the differentiation of species in Amazonia during the course of geological history are based on different factors, as follow: (1) Changes in the distribution of land and sea or in the landscape due to tectonic movements or sea level fluctuations (Paleogeography hypothesis), (2) the barrier effect of Amazonian rivers (River hypothesis), (3) a combination of the barrier effect of broad rivers and vegetational changes in northern and southern Amazonia (River-refuge hypothesis), (4) the isolation of humid rainforest blocks near areas of surface relief in the periphery of Amazonia separated by dry forests, savannas and other intermediate vegetation types during dry climatic periods of the Tertiary and Quaternary (Refuge hypothesis), (5) changes in canopy-density due to climatic reversals (Canopy-density hypothesis) (6) the isolation and speciation of animal populations in small montane habitat pockets around Amazonia due to climatic fluctuations without major vegetational changes (Museum hypothesis), (7) competitive species interactions and local species isolations in peripheral regions of Amazonia due to invasion and counterinvasion during cold/warm periods of the Pleistocene (Disturbance-vicariance hypothesis) and (8) parapatric speciation across steep environmental gradients without separation of the respective populations (Gradient hypothesis). Several of these hypotheses probably are relevant to a different degree for the speciation processes in different faunal groups or during different geological periods. The basic paleogeography model refers mainly to faunal differentiation during the Tertiary and in combination with the Refuge hypothesis. Milankovitch‡ cycles leading to global main hypotheses proposed to explain barrier formation separating populations and causing the differentiation of species in Amazonia during the course of geological history are based on different factors, as follow: (1) Changes in the distribution of land and sea or in the landscape due to tectonic movements or sea level fluctuations (Paleogeography hypothesis), (2) the barrier effect of Amazonian rivers (River hypothesis), (3) a combination of the barrier effect of broad rivers and vegetational changes in northern and southern Amazonia (River-refuge hypothesis), (4) the isolation of humid rainforest blocks near areas of surface relief in the periphery of Amazonia separated by dry forests, savannas and other intermediate vegetation types during dry climatic periods of the Tertiary and Quaternary (Refuge hypothesis), (5) changes in canopy-density due to climatic reversals (Canopy-density hypothesis) (6) the isolation and speciation of animal populations in small montane habitat pockets around Amazonia due to climatic fluctuations without major vegetational changes (Museum hypothesis), (7) competitive species interactions and local species isolations in peripheral regions of Amazonia due to invasion and counterinvasion during cold/warm periods of the Pleistocene (Disturbance-vicariance hypothesis) and (8) parapatric speciation across steep environmental gradients without separation of the respective populations (Gradient hypothesis). Several of these hypotheses probably are relevant to a different degree for the speciation processes in different faunal groups or during different geological periods. The basic paleogeography model refers mainly to faunal differentiation during the Tertiary and in combination with the Refuge hypothesis. Milankovitch cycles leading to global climatic-vegetational changes affected the biomes of the world not only during the Pleistocene but also during the Tertiary and earlier geological periods. New geoscientific evidence for the effect of dry climatic periods in Amazonia supports the predictions of the Refuge hypothesis. The disturbance-vicariance hypothesis refers to the presumed effect of cold/warm climatic phases of the Pleistocene only and is of limited general relevance because most extant species originated earlier and probably through paleogeographic changes and the formation of ecological refuges during the Tertiary.

scholarly journals Environment affects specialisation of plants and pollinators

2019 ◽  
Author(s):  
E. Fernando Cagua ◽  
Audrey Lustig ◽  
Jason M. Tylianakis ◽  
Daniel B. Stouffer
Keyword(s):  
Environmental Stress ◽  
Community Composition ◽  
Environmental Conditions ◽  
Species Interactions ◽  
Evolutionary History ◽  
Environmental Gradients ◽  
Species Traits ◽  
Environmental Variable ◽  
Species Level ◽  
Plant Pollinator

AbstractWhat determines whether or not a species is a generalist or a specialist? Evidence that the environment can influence species interactions is rapidly accumulating. However, a systematic link between environment and the number of partners a species interacts with has been elusive so far. Presumably, because environmental gradients appear to have contrasting effects on species depending on the environmental variable. Here, we test for a relationship between the stresses imposed by the environment, instead of environmental gradients directly, and species specialisation using a global dataset of plant-pollinator interactions. We found that the environment can play a significant effect on specialisation, even when accounting for community composition, likely by interacting with species’ traits and evolutionary history. Species that have a large number of interactions are more likely to focus on a smaller number of, presumably higher-quality, interactions under stressful environmental conditions. Contrastingly, the specialists present in multiple locations are more likely to broaden their niche, presumably engaging in opportunistic interactions to cope with increased environmental stress. Indeed, many apparent specialists effectively behave as facultative generalists. Overall, many of the species we analysed are not inherently generalist or specialist. Instead, species’ level of specialisation should be considered on a relative scale depending on where they are found and the environmental conditions at that location.

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