Niche difference determines coexistence and similar underlying processes in four ecological groups

2021 ◽  
Author(s):  
Lisa Buche ◽  
Juerg W Spaak ◽  
Javier Jarillo Diaz ◽  
Frederik de Laender
Keyword(s):  
Species Interactions ◽  
Species Coexistence ◽  
Ecological Groups ◽  
Annual Plants ◽  
Perennial Plant ◽  
Niche Differences ◽  
Species Pairs ◽  
Community Types ◽  
Underlying Processes ◽  
Important Objective

Understanding how species interactions affect community composition is an important objective in ecology. Yet, the multitude of methods to study coexistence has hampered cross-community comparisons. Here, we standardized niche and fitness differences across 1018 species pairs to compare the processes driving composition and outcomes, among four community types (annual plant, perennial plant, phytoplankton, and bacteria/yeast). First, we show that niche differences are more important drivers of coexistence than fitness differences. Second, in all community types negative frequency dependence is the most frequent process. Finally, the outcome of species interactions differs among community types. Coexistence was the most frequent outcome for perennial plants and phytoplankton, while competitive exclusion was the most prevalent outcome in annual plants and bacteria/yeasts. Overall, our results show that niche and fitness differences can be used as a common currency that allow cross community comparisons to understand species coexistence.

scholarly journals Plant functional traits and the multidimensional nature of species coexistence

2015 ◽  
Vol 112 (3) ◽  
pp. 797-802 ◽  
Author(s):  
Nathan J. B. Kraft ◽  
Oscar Godoy ◽  
Jonathan M. Levine
Keyword(s):  
Functional Traits ◽  
Community Dynamics ◽  
Species Coexistence ◽  
Plant Functional Traits ◽  
Annual Plants ◽  
Phenotypic Differences ◽  
Niche Differences ◽  
Whole Plant ◽  
Complex Relationships ◽  
Average Fitness

Understanding the processes maintaining species diversity is a central problem in ecology, with implications for the conservation and management of ecosystems. Although biologists often assume that trait differences between competitors promote diversity, empirical evidence connecting functional traits to the niche differences that stabilize species coexistence is rare. Obtaining such evidence is critical because traits also underlie the average fitness differences driving competitive exclusion, and this complicates efforts to infer community dynamics from phenotypic patterns. We coupled field-parameterized mathematical models of competition between 102 pairs of annual plants with detailed sampling of leaf, seed, root, and whole-plant functional traits to relate phenotypic differences to stabilizing niche and average fitness differences. Single functional traits were often well correlated with average fitness differences between species, indicating that competitive dominance was associated with late phenology, deep rooting, and several other traits. In contrast, single functional traits were poorly correlated with the stabilizing niche differences that promote coexistence. Niche differences could only be described by combinations of traits, corresponding to differentiation between species in multiple ecological dimensions. In addition, several traits were associated with both fitness differences and stabilizing niche differences. These complex relationships between phenotypic differences and the dynamics of competing species argue against the simple use of single functional traits to infer community assembly processes but lay the groundwork for a theoretically justified trait-based community ecology.

scholarly journals A quantitative synthesis of soil microbial effects on plant species coexistence

2021 ◽  
Author(s):  
Xinyi Yan ◽  
Jonathan M. Levine ◽  
Gaurav S. Kandlikar
Keyword(s):  
Species Interactions ◽  
Soil Microbes ◽  
Species Coexistence ◽  
Meta Analysis ◽  
Priority Effects ◽  
Soil Microbial ◽  
Plant Soil ◽  
Niche Differences ◽  
Plant Coexistence ◽  
Microbial Effects

Soil microorganisms play a major role in shaping plant diversity, not only through their direct effects as pathogens, mutualists, and decomposers, but also by altering interactions between plants. In particular, previous research has shown that the soil community often generates frequency-dependent feedback loops among plants that can either destabilize species interactions, or generate stabilizing niche differences that promote species coexistence. However, recent insights from modern coexistence theory have shown that microbial effects on plant coexistence depend not only on these stabilizing or destabilizing effects, but also on the degree to which they generate competitive fitness differences. While many previous experiments have generated the data necessary for evaluating microbially mediated fitness differences, these effects have rarely been quantified in the literature. Here we present a meta-analysis of data from 50 studies, which we used to quantify the microbially mediated (de)stabilization and fitness differences derived from a classic plant-soil feedback model. Across 518 pairwise comparisons, we found that soil microbes generated both stabilization (or destabilization) and fitness differences, but also that the microbially mediated fitness differences dominated. As a consequence, if plants are otherwise equivalent competitors, the balance of soil microbe-generated (de)stabilization and fitness differences drives species exclusion much more frequently than coexistence or priority effects. Our work shows that microbially mediated fitness differences are an important but overlooked effect of soil microbes on plant coexistence. This finding paves the way for a more complete understanding of the processes that maintain plant biodiversity.

scholarly journals Intuitive and broadly applicable definitions of niche and fitness differences

2018 ◽  
Author(s):  
Jurg W. Spaak ◽  
Frederik De Laender
Keyword(s):  
Experimental Data ◽  
Frequency Dependence ◽  
Community Ecology ◽  
Species Interactions ◽  
Theoretical Models ◽  
Coexistence Theory ◽  
Niche Differences ◽  
Community Types ◽  
Specific Community ◽  
Definition Of

AbstractExplaining nature’s biodiversity is a key challenge for science. To persist, populations must be able to grow faster when rare, a feature called negative frequency dependence and quantified as ‘niche differences’ (𝒩) in coexistence theory. Here, we first show that available definitions of 𝒩 differ in how 𝒩 link to species interactions, are difficult to interpret, and often apply to specific community types only. We then present a new definition of 𝒩 that is intuitive and applicable to a broader set of (modelled and empirical) communities than is currently the case, filling a main gap in the literature. Given 𝒩, we also re-define fitness differences (ℱ) and illustrate how 𝒩 and ℱ determine coexistence. Finally, we demonstrate how to apply our definitions to theoretical models and experimental data, and provide ideas on how they can facilitate comparison and synthesis in community ecology.

scholarly journals Winter in water: Differential responses and the maintenance of biodiversity

2019 ◽  
Author(s):  
Bailey McMeans ◽  
Kevin McCann ◽  
Matthew Guzzo ◽  
Timothy Bartley ◽  
Carling Bieg ◽  
...  
Keyword(s):  
Species Interactions ◽  
Species Coexistence ◽  
Thermal Environment ◽  
Biotic Interactions ◽  
Light Sensitivity ◽  
Research Area ◽  
Subarctic Lakes ◽  
Winter Activity ◽  
Niche Differences ◽  
Differential Responses

The ecological consequences of winter in freshwater systems are an understudied but rapidly emerging research area. Here, we argue that winter periods of reduced temperature and light (and potentially oxygen and resources) could play an underappreciated role in mediating the coexistence of species. This may be especially true for temperate and subarctic lakes, where seasonal changes in the thermal environment might fundamentally structure species interactions. With climate change already shortening ice-covered periods on temperate and polar lakes, consideration of how winter conditions shape biotic interactions is urgently needed. Using freshwater fishes in northern temperate lakes as a case study, we demonstrate how physiological trait differences (e.g., thermal preference, light sensitivity) drive differential behavioral responses to winter among competing species. Specifically, some species have a higher capacity for winter activity than others. Existing and new theory is presented to argue that such differential responses to winter can promote species coexistence. Importantly, if winter is a driver of niche differences that weaken competition between relative to within species, then shrinking winter periods could threaten coexistence by tipping the scales in favor of certain sets of species over others.

scholarly journals Topographic Effects on the Spatial Species Associations in Diverse Heterogeneous Tropical Evergreen Forests

2021 ◽  
Vol 13 (5) ◽  
pp. 2468
Author(s):  
Nguyen Hong Hai ◽  
Yousef Erfanifard ◽  
Van Bac Bui ◽  
Trinh Hien Mai ◽  
Any Mary Petritan ◽  
...  
Keyword(s):  
Species Interactions ◽  
Species Coexistence ◽  
Spatial Scales ◽  
Interspecific Interactions ◽  
Spatial Association ◽  
Topographic Effects ◽  
Habitat Association ◽  
Important Species ◽  
Evergreen Forests ◽  
Partial Overlap

Studying spatial patterns and habitat association of plant communities may provide understanding of the ecological mechanisms and processes that maintain species coexistence. To conduct assessments of correlation between community compositions and habitat association, we used data from two topographically different plots with 2 ha area in tropical evergreen forests with the variables recorded via grid systems of 10 × 10 m subplots in Northern-Central Vietnam. First, we tested the relationship between community composition and species diversity indices considering the topographical variables. We then assessed the interspecific interactions of 20 dominant plant species using the nearest-neighbor distribution function, Dij(r), and Ripley’s K-function, Kij(r). Based on the significant spatial association of species pairs, indices of interspecific interaction were calculated by the quantitative amounts of the summary statistics. The results showed that (i) community compositions were significantly influenced by the topographic variables and (ii) almost 50% significant pairs of species interactions were increased with increasing spatial scales up to 10–15 m, then declined and disappeared at scales of 30–40 m. Segregation and partial overlap were the dominant association types and disappeared at larger spatial scales. Spatial segregation, mixing, and partial overlap revealed the important species interactions in maintaining species coexistence under habitat heterogeneity in diverse forest communities.

scholarly journals Genotype-Species Interactions in Neighbourhoods of Forest Tree Communities

2007 ◽  
Vol 56 (1-6) ◽  
pp. 101-110 ◽  
Author(s):  
Chr. Wehenkel ◽  
F. Bergmann ◽  
H.-R. Gregorius
Keyword(s):  
Species Interactions ◽  
Species Coexistence ◽  
Biotic Interactions ◽  
Forest Tree ◽  
Target Species ◽  
Species Identity ◽  
Enzymatic Function ◽  
Genotype Frequencies ◽  
Tree Communities ◽  
Large Survey

Abstract Studies on plant communities of various annual species suggest that there are particular biotic interactions among individuals from different species which could be the basis for long-term species coexistence. In the course of a large survey on species-genetic diversity relationships in several forest tree communities, it was found that statistically significant differences exist among isozyme genotype frequencies of conspecific tree groups, which differ only by species identity of their neighbours. Based on a specific measure, the association of the neighbouring species with the genotypes of the target species or that of the genotypes with the neighbouring species was quantified. Since only AAT and HEK of the five analysed enzyme systems differed in their genotype frequencies among several tree groups of the same target species, a potential involvement of their enzymatic function in the observed differences was discussed. The results of this study demonstrate a fine-scale genetic differentiation within single tree species of forest communities, which may be the result of biotic interactions between the genetic structure of a species and the species composition of its community. This observation also suggests the importance of intraspecific genetic variation for interspecific adaptation.

scholarly journals Metabolic Symbiosis Facilitates Species Coexistence and Generates Light-Dependent Priority Effects

2021 ◽  
Vol 8 ◽  
Author(s):  
Veronica Hsu ◽  
Holly V. Moeller
Keyword(s):  
Carbon Source ◽  
Community Composition ◽  
Green Algae ◽  
Species Interactions ◽  
Species Coexistence ◽  
Priority Effects ◽  
Competitive Interactions ◽  
Paramecium Bursaria ◽  
Mutual Benefit ◽  
Cascading Effects

Metabolic symbiosis is a form of symbiosis in which organisms exchange metabolites, typically for mutual benefit. For example, acquired phototrophs like Paramecium bursaria obtain photosynthate from endosymbiotic green algae called Chlorella. In addition to facilitating the persistence of P. bursaria by providing a carbon source that supplements P. bursaria’s heterotrophic digestion of bacteria, symbiotic Chlorella may impact competitive interactions between P. bursaria and other bacterivores, with cascading effects on community composition and overall diversity. Here, we tested the effects of metabolic symbiosis on coexistence by assessing the impacts of acquired phototrophy on priority effects, or the effect of species arrival order on species interactions, between P. bursaria and its competitor Colpidium. Our results suggest light-dependent priority effects. The acquired phototroph benefited from metabolic symbiosis during sequential arrival of each organism in competition, and led to increased growth of late-arriving Colpidium. These findings demonstrate that understanding the consequences of priority effects for species coexistence requires consideration of metabolic symbiosis.

Metacommunities

2019 ◽  
pp. 266-284
Author(s):  
Gary G. Mittelbach ◽  
Brian J. McGill
Keyword(s):  
Species Diversity ◽  
Species Interactions ◽  
Neutral Theory ◽  
Patch Dynamics ◽  
Species Traits ◽  
Local Communities ◽  
The Other ◽  
Species Sorting ◽  
Niche Differences ◽  
Dynamics Of Populations

Just as the dispersal of individuals may link the dynamics of populations in space, the dispersal of species among communities may link local communities into a metacommunity. Four different perspectives characterize how dispersal rates, environmental heterogeneity, and species traits interact to influence diversity in metacommunities. These perspectives are: patch dynamics, species sorting, mass effects, and the neutral perspective. The neutral perspective stands in stark contrast to the other three perspectives in that it assumes that niche differences between species are unimportant and that species are demographically identical in terms of their birth, death, and dispersal rates. Under the neutral perspective, species diversity is maintained by a balance between speciation, extinction, and dispersal. Although neutral theory is incompatible with realistic modes and rates of speciation, it has been enormously influential in focusing our attention on the linkages between species interactions on local scales, and evolutionary and biogeographic processes occurring on large scales.

scholarly journals Biotic rescaling reveals importance of species interactions for variation in biodiversity responses to climate change

2020 ◽  
Vol 117 (37) ◽  
pp. 22858-22865 ◽  
Author(s):  
Vigdis Vandvik ◽  
Olav Skarpaas ◽  
Kari Klanderud ◽  
Richard J. Telford ◽  
Aud H. Halbritter ◽  
...  
Keyword(s):  
Climate Change ◽  
Species Interactions ◽  
Community Dynamics ◽  
Biotic Interactions ◽  
Plant Interactions ◽  
Climate Gradients ◽  
Climate Change Responses ◽  
Local Extinctions ◽  
Future Work ◽  
Underlying Processes

Generality in understanding biodiversity responses to climate change has been hampered by substantial variation in the rates and even directions of response to a given change in climate. We propose that such context dependencies can be clarified by rescaling climate gradients in terms of the underlying biological processes, with biotic interactions as a particularly important process. We tested this rescaling approach in a replicated field experiment where entire montane grassland communities were transplanted in the direction of expected temperature and/or precipitation change. In line with earlier work, we found considerable variation across sites in community dynamics in response to climate change. However, these complex context dependencies could be substantially reduced or eliminated by rescaling climate drivers in terms of proxies of plant−plant interactions. Specifically, bryophytes limited colonization by new species into local communities, whereas the cover of those colonists, along with bryophytes, were the primary drivers of local extinctions. These specific interactions are relatively understudied, suggesting important directions for future work in similar systems. More generally, the success of our approach in explaining and simplifying landscape-level variation in climate change responses suggests that developing and testing proxies for relevant underlying processes could be a fruitful direction for building more general models of biodiversity response to climate change.

Phenological displacement is uncommon among sympatric angiosperms

2020 ◽  
Author(s):  
Daniel S. Park ◽  
Ian K. Breckheimer ◽  
Aaron M. Ellison ◽  
Goia M. Lyra ◽  
Charles C. Davis
Keyword(s):  
Flowering Time ◽  
Related Species ◽  
Species Interactions ◽  
Spatial Scales ◽  
Character Displacement ◽  
Future Climate Change ◽  
Herbarium Specimens ◽  
Reproductive Character Displacement ◽  
Closely Related Species ◽  
Species Pairs

AbstractInteractions between species can influence access to resources and successful reproduction. One possible outcome of such interactions is reproductive character displacement. Here, the similarity of reproductive traits – such as flowering time – among close relatives growing in sympatry differ more so than when growing apart. However, evidence for the overall prevalence and direction of this phenomenon, or the stability of such differences under environmental change, remains untested across large taxonomic and spatial scales. We apply data from tens of thousands of herbarium specimens to examine character displacement in flowering time across 110 animal-pollinated angiosperm species in the eastern USA. We demonstrate that the degree and direction of phenological displacement among co-occurring closely related species pairs varies tremendously. Overall, flowering time displacement in sympatry is not common. However, displacement is generally greater among species pairs that flower close in time, regardless of direction. We additionally identify that future climate change may alter the nature of phenological displacement among many of these species pairs. On average, flowering times of closely related species were predicted to shift further apart by the mid-21st century, which may have significant future consequences for species interactions and gene flow.

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