scholarly journals Applying modern coexistence theory to priority effects

2019 ◽  
Vol 116 (13) ◽  
pp. 6205-6210 ◽  
Author(s):  
Tess Nahanni Grainger ◽  
Andrew D. Letten ◽  
Benjamin Gilbert ◽  
Tadashi Fukami
Keyword(s):  
Growth Rates ◽  
Competitive Exclusion ◽  
Abiotic Factors ◽  
Priority Effects ◽  
Competitive Interactions ◽  
Competing Species ◽  
Coexistence Theory ◽  
Dependent Growth ◽  
Established Population ◽  
Positive Frequency

Modern coexistence theory is increasingly used to explain how differences between competing species lead to coexistence versus competitive exclusion. Although research testing this theory has focused on deterministic cases of competitive exclusion, in which the same species always wins, mounting evidence suggests that competitive exclusion is often historically contingent, such that whichever species happens to arrive first excludes the other. Coexistence theory predicts that historically contingent exclusion, known as priority effects, will occur when large destabilizing differences (positive frequency-dependent growth rates of competitors), combined with small fitness differences (differences in competitors’ intrinsic growth rates and sensitivity to competition), create conditions under which neither species can invade an established population of its competitor. Here we extend the empirical application of modern coexistence theory to determine the conditions that promote priority effects. We conducted pairwise invasion tests with four strains of nectar-colonizing yeasts to determine how the destabilizing and fitness differences that drive priority effects are altered by two abiotic factors characterizing the nectar environment: sugar concentration and pH. We found that higher sugar concentrations increased the likelihood of priority effects by reducing fitness differences between competing species. In contrast, higher pH did not change the likelihood of priority effects, but instead made competition more neutral by bringing both fitness differences and destabilizing differences closer to zero. This study demonstrates how the empirical partitioning of priority effects into fitness and destabilizing components can elucidate the pathways through which environmental conditions shape competitive interactions.

scholarly journals Experimental evaluation of ecological principles to understand and modulate the outcome of bacterial strain competition in gut microbiomes

2020 ◽  
Author(s):  
Rafael R. Segura Munoz ◽  
Sara Mantz ◽  
Ines Martinez ◽  
Robert J. Schmaltz ◽  
Jens Walter ◽  
...  
Keyword(s):  
Bacterial Strain ◽  
Competitive Exclusion ◽  
Niche Partitioning ◽  
Priority Effects ◽  
Competitive Interactions ◽  
Competitive Fitness ◽  
Coexistence Theory ◽  
Strain Competition ◽  
Ecological Principles ◽  
The Impact

Abstract It is unclear if coexistence theory can be applied to gut microbiomes to understand their characteristics and modulate their composition. Through strictly controlled colonization experiments in mice, we demonstrated that strains of Akkermansia muciniphila and Bacteroides vulgatus could only be established if microbiomes were devoid of exactly these species. Strains of A. muciniphila showed strict competitive exclusion, while B. vulgates strains coexistedbut populations were still influenced by competitive interactions. Priority effects were detected for both species as strains’ competitive fitness increased when colonizing first. Based on these observations, we devised a subtractive strategy for A. muciniphila using antibiotics and demonstrated that a strain from an assembled community can be stably replaced by another strain. Altogether, these results suggest that aspects of coexistence theory, e.g., niche partitioning and the impact of priority effects on fitness differences, can be applied to explain ecological characteristics of gut microbiomes and modulate their composition.

scholarly journals Coexistence theory and the frequency-dependence of priority effects

2018 ◽  
Author(s):  
Po-Ju Ke ◽  
Andrew D. Letten
Keyword(s):  
Frequency Dependence ◽  
Priority Effects ◽  
Coexistence Theory ◽  
Positive Frequency Dependence ◽  
Positive Frequency

AbstractPriority effects encompass a broad suite of ecological phenomena. Several studies have suggested reframing priority effects around the stabilizing and equalizing concepts of coexistence theory. We show that the only compatible priority effects are those characterized by positive frequency dependence.

Effects of turbidity on prey consumption and growth in brook trout and implications for bioenergetics modeling

2001 ◽  
Vol 58 (2) ◽  
pp. 386-393 ◽  
Author(s):  
John A Sweka ◽  
Kyle J Hartman
Keyword(s):  
Growth Rates ◽  
Brook Trout ◽  
Specific Growth ◽  
Abiotic Factors ◽  
Foraging Strategies ◽  
Turbid Water ◽  
Daily Consumption ◽  
Consumption Rates ◽  
The Difference ◽  
Specific Growth Rates

Brook trout (Salvelinus fontinalis) were held in an artificial stream to observe the influence of turbidity on mean daily consumption and specific growth rates. Treatment turbidity levels ranged from clear (<3.0 nephelometric turbidity units (NTU)) to very turbid water (> 40 NTU). Observed mean daily specific consumption rates were standardized to the mean weight of all brook trout tested. Turbidity had no significant effect on mean daily consumption, but specific growth rates decreased significantly as turbidity increased. Brook trout in turbid water became more active and switched foraging strategies from drift feeding to active searching. This switch was energetically costly and resulted in lower specific growth rates in turbid water as compared with clear water. Bioenergetics simulations were run to compare observed growth with that predicted by the model. Observed growth values fell below those predicted by the model and the difference increased as turbidity increased. Abiotic factors, such as turbidity, which bring about changes in the activity rates of fish, can have implications for the accuracy of predicted growth by bioenergetics models.

Do abiotic mechanisms determine interannual variability in length-at-age of juvenile Arcto-Norwegian cod?

2002 ◽  
Vol 59 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Geir Ottersen ◽  
Kristin Helle ◽  
Bjarte Bogstad
Keyword(s):  
Growth Rates ◽  
Gadus Morhua ◽  
Barents Sea ◽  
Water Masses ◽  
Inverse Relation ◽  
Lower Growth ◽  
Density Dependent ◽  
The Barents Sea ◽  
The Mean ◽  
Dependent Growth

For the large Arcto-Norwegian stock of cod (Gadus morhua L.) in the Barents Sea, year-to-year variability in growth is well documented. Here three hypotheses for the observed inverse relation between abundance and the mean length-at-age of juveniles (ages 1–4) are suggested and evaluated. Based on comprehensive data, we conclude that year-to-year differences in length-at-age are mainly determined by density-independent mechanisms during the pelagic first half year of the fishes' life. Enhanced inflow from the southwest leads to an abundant cohort at the 0-group stage being distributed farther east into colder water masses, causing lower postsettlement growth rates. We can not reject density-dependent growth effects related to variability in food rations, but our data do not suggest this to be the main mechanism. Another hypothesis suggests that lower growth rates during periods of high abundance are a result of density-dependent mechanisms causing the geographic range of juveniles to extend eastwards into colder water masses. This is rejected mainly because year-to-year differences in mean length are established by age 2, which is too early for movements over large distances.

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.

Competition between native and non-native plants.

2020 ◽  
pp. 291-307
Author(s):  
Elizabeth M. Wandrag ◽  
◽  
Jane A. Catford ◽  
◽  
◽  
...  
Keyword(s):  
Plant Species ◽  
Plant Communities ◽  
Native Species ◽  
Abiotic Factors ◽  
Invasion Biology ◽  
Competitive Interactions ◽  
Native Plant ◽  
Native Plant Species ◽  
New Locations ◽  
Strength Of Competition

The introduction of species to new locations leads to novel competitive interactions between resident native and newly-arriving non-native species. The nature of these competitive interactions can influence the suitability of the environment for the survival, reproduction and spread of non-native plant species, and the impact those species have on native plant communities. Indeed, the large literature on competition among plants reflects its importance in shaping the composition of plant communities, including the invasion success of non-native species. While competition and invasion theory have historically developed in parallel, the increasing recognition of the synergism between the two themes has led to new insights into how non-native plant species invade native plant communities, and the impacts they have on those plant communities. This chapter provides an entry point into the aspects of competition theory that can help explain the success, dominance and impacts of invasive species. It focuses on resource competition, which arises wherever the resources necessary for establishment, survival, reproduction and spread are in limited supply. It highlights key hypotheses developed in invasion biology that relate to ideas of competition, outlines biotic and abiotic factors that influence the strength of competition and species' relative competitive abilities, and describes when and how competition between non-native and native plant species can influence invasion outcomes. Understanding the processes that influence the strength of competition between non-native and native plant species is a necessary step towards understanding the causes and consequences of biological invasions.

CVD Filling of Narrow Deep 4H-SiC Trenches in a Quasi-Selective Epitaxial Growth Mode

2018 ◽  
Vol 924 ◽  
pp. 116-119 ◽  
Author(s):  
Shi Yang Ji ◽  
Ryoji Kosugi ◽  
Kazutoshi Kojima ◽  
Kazuhiro Mochizuki ◽  
Yasuyuki Kawada ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Epitaxial Growth ◽  
Growth Rates ◽  
Low Risk ◽  
Growth Mode ◽  
Flow Rates ◽  
Defect Generation ◽  
Selective Epitaxial Growth ◽  
Dependent Growth

By mapping the source and HCl flow rates dependent growth rates, the evolving trend of a quasi-selective epitaxial growth (quasi-SEG) that growing very thin epilayer on mesa top and ensuring an extremely low risk of voids defect generation was firstly figured out on a 5-μm 4H-SiC trench. Then, basing on the acquired knowledge, a 25-μm 4H-SiC trench with an aspect ratio up to ~10 was completely filled in the quasi-SEG mode.

Growth Patterns in Bluegill (Lepomis macrochirus) and Pumpkinseed (L. gibbosus) Sunfish: Environmental Variation and the Importance of Ontogenetic Niche Shifts

1988 ◽  
Vol 45 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Craig W. Osenberg ◽  
Earl E. Werner ◽  
Gary G. Mittelbach ◽  
Donald J. Hall
Keyword(s):  
Growth Rates ◽  
Lepomis Macrochirus ◽  
Growth Patterns ◽  
Adult Performance ◽  
Littoral Habitat ◽  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Dependent Growth ◽  
Specific Growth Rates ◽  
Recent Experimental Work

Size-specific growth rates were determined for bluegill (Lepomis macrochirus) and pumpkinseed (L. gibbosus) sunfish collected between 1978 and 1985 in nine lakes in southwestern Michigan. Variation in growth rates was attributable to lake effects as well as an interaction between lake and year effects. Year effects explained none of the observed variation, suggesting that growth rates were influenced more by unique lake differences than by annual climatic differences. Analyses of the covariation in growth among different size-classes of bluegill and pumpkinseed revealed that small bluegill (< 55 mm standard length (SL)) and small pumpkinseed (< 40 mm SL) exhibited similar responses to environmental factors, while large bluegill (> 55 mm SL) and large pumpkinseed (> 50 mm SL) responded differently. These breaks in the growth patterns coincide with the sizes at which each species exhibits an ontogenetic shift in diet. Comparison of growth rates and resource densities suggests that the growth rates of the large fishes were food limited. Small fishes showed significant density-dependent growth. This correlative evidence for competition is in agreement with recent experimental work. We suggest that the competition between juvenile sunfishes is driven by the effects of adult resources on adult performance and the eventual recruitment of juveniles into the littoral habitat.

Sign in / Sign up

Export Citation Format

Share Document