Species coexistence and niche theory

2019 ◽  
pp. 141-157
Author(s):  
Gary G. Mittelbach ◽  
Brian J. McGill
Keyword(s):  
Interspecific Competition ◽  
Species Coexistence ◽  
Apparent Competition ◽  
Competing Species ◽  
Invasion Fitness ◽  
Niche Differences ◽  
Trade Offs ◽  
Coexistence Mechanisms ◽  
The Face ◽  
Multiple Species

Ecologists have long puzzled over the question of how multiple species may coexist in a community in the face of strong interspecific competition. This chapter explores the answers that modern coexistence theory provides to this question. Spatial and temporal heterogeneity in the environment, in conjunction with species differences in resource use and dispersal (niche differences and trade-offs) provide important general coexistence mechanisms. More specifically, theory shows that stable species coexistence is enhanced when intraspecific competition is stronger than interspecific competition (α‎jj>α‎ji). Recent theoretical developments show how this criteria for coexistence (α‎jj>α‎ji) is related to two different aspects of the niche. Less niche overlap between competing species provides a positive stabilizing effect on species coexistence, whereas greater equality in the invasion fitness of competing species provides a positive equalizing effect on coexistence. Analysis of models of apparent competition due to shared predation yield similar conclusions.

scholarly journals Assessing the Impacts of Competition and Dispersal on a Multiple Interactions Type Model

2021 ◽  
Vol 29 (3) ◽  
Author(s):  
Murtala Bello Aliyu ◽  
Mohd Hafiz Mohd ◽  
Mohd Salmi Md. Noorani
Keyword(s):  
Bifurcation Analysis ◽  
Species Coexistence ◽  
Real Life ◽  
Period Doubling ◽  
Type Model ◽  
Coexistence Mechanisms ◽  
Multiple Species ◽  
The Stability ◽  
Transcritical Bifurcations ◽  
Multiple Interactions

Multiple interactions (e.g., mutualist-resource-competitor-exploiter interactions) type models are known to exhibit oscillatory behaviour as a result of their complexity. This large-amplitude oscillation often de-stabilises multispecies communities and increases the chances of species extinction. What mechanisms help species in a complex ecological system to persist? Some studies show that dispersal can stabilise an ecological community and permit multi-species coexistence. However, previous empirical and theoretical studies often focused on one- or two-species systems, and in real life, we have more than two-species coexisting together in nature. Here, we employ a (four-species) multiple interactions type model to investigate how competition interacts with other biotic factors and dispersal to shape multi-species communities. Our results reveal that dispersal has (de-)stabilising effects on the formation of multi-species communities, and this phenomenon shapes coexistence mechanisms of interacting species. These contrasting effects of dispersal can best be illustrated through its combined influences with the competition. To do this, we employ numerical simulation and bifurcation analysis techniques to track the stable and unstable attractors of the system. Results show the presence of Hopf bifurcations, transcritical bifurcations, period-doubling bifurcations and limit point bifurcations of cycles as we vary the competitive strength in the system. Furthermore, our bifurcation analysis findings show that stable coexistence of multiple species is possible for some threshold values of ecologically-relevant parameters in this complex system. Overall, we discover that the stability and coexistence mechanisms of multiple species depend greatly on the interplay between competition, other biotic components and dispersal in multi-species ecological systems.

scholarly journals Effects of rapid evolution on species coexistence

2019 ◽  
Vol 116 (6) ◽  
pp. 2112-2117 ◽  
Author(s):  
Simon P. Hart ◽  
Martin M. Turcotte ◽  
Jonathan M. Levine
Keyword(s):  
Population Dynamics ◽  
Species Diversity ◽  
Interspecific Competition ◽  
Species Coexistence ◽  
Rapid Evolution ◽  
Empirical Work ◽  
Niche Differentiation ◽  
Ecological Communities ◽  
Competing Species ◽  
Ecological Processes

Increasing evidence for rapid evolution suggests that the maintenance of species diversity in ecological communities may be influenced by more than purely ecological processes. Classic theory shows that interspecific competition may select for traits that increase niche differentiation, weakening competition and thus promoting species coexistence. While empirical work has demonstrated trait evolution in response to competition, if and how evolution affects the dynamics of the competing species—the key step for completing the required eco-evolutionary feedback—has been difficult to resolve. Here, we show that evolution in response to interspecific competition feeds back to change the course of competitive population dynamics of aquatic plant species over 10–15 generations in the field. By manipulating selection imposed by heterospecific competitors in experimental ponds, we demonstrate that (i) interspecific competition drives rapid genotypic change, and (ii) this evolutionary change in one competitor, while not changing the coexistence outcome, causes the population trajectories of the two competing species to converge. In contrast to the common expectation that interspecific competition should drive the evolution of niche differentiation, our results suggest that genotypic evolution resulted in phenotypic changes that altered population dynamics by affecting the competitive hierarchy. This result is consistent with theory suggesting that competition for essential resources can limit opportunities for the evolution of niche differentiation. Our finding that rapid evolution regulates the dynamics of competing species suggests that ecosystems may rely on continuous feedbacks between ecology and evolution to maintain species diversity.

scholarly journals Combined Impacts of Predation, Mutualism and Dispersal on the Dynamics of a Four-Species Ecological System

2021 ◽  
Vol 29 (1) ◽  
Author(s):  
Murtala Bello Aliyu ◽  
Mohd Hafiz Mohd
Keyword(s):  
Hopf Bifurcation ◽  
Species Interactions ◽  
Species Coexistence ◽  
Biotic Interactions ◽  
Ecological System ◽  
Stable Limit ◽  
Combined Effects ◽  
Coexistence Mechanisms ◽  
Multiple Species ◽  
The Stability

Multi-species and ecosystem models have provided ecologist with an excellent opportunity to study the effects of multiple biotic interactions in an ecological system. Predation and mutualism are among the most prevalent biotic interactions in the multi-species system. Several ecological studies exist, but they are based on one-or two-species interactions, and in real life, multiple interactions are natural characteristics of a multi-species community. Here, we use a system of partial differential equations to study the combined effects of predation, mutualism and dispersal on the multi-species coexistence and community stability in the ecological system. Our results show that predation provided a defensive mechanism against the negative consequences of the multiple species interactions by reducing the net effect of competition. Predation is critical in the stability and coexistence of the multi-species community. The combined effects of predation and dispersal enhance the multiple species coexistence and persistence. Dispersal exerts a positive effect on the system by supporting multiple species coexistence and stability of community structures. Dispersal process also reduces the adverse effects associated with multiple species interactions. Additionally, mutualism induces oscillatory behaviour on the system through Hopf bifurcation. The roles of mutualism also support multiple species coexistence mechanisms (for some threshold values) by increasing the stable coexistence and the stable limit cycle regions. We discover that the stability and coexistence mechanisms are controlled by the transcritical and Hopf bifurcation that occurs in this system. Most importantly, our results show the important influences of predation, mutualism and dispersal in the stability and coexistence of the multi-species communities

More Modules

2011 ◽  
Author(s):  
Kevin S. McCann
Keyword(s):  
Population Dynamics ◽  
Food Webs ◽  
Empirical Evidence ◽  
Intraguild Predation ◽  
Weak Interactions ◽  
Apparent Competition ◽  
Trade Offs ◽  
Variable Population ◽  
The Stability

This chapter considers four-species modules and the role of generalism (effectively a three-species module with a consumer feeding on two resources). It first examines how generalists affect the dynamics of food webs by focusing on a set of modules that contrast generalist consumer dynamics relative to the specialist case. It then discusses organismal trade-offs that play a role in governing the diamond food web module and the intraguild predation module, arguing that such tradeoffs influence the flux of matter, the organization of interaction strengths, and ultimately the stability of communities. The chapter also reviews empirical evidence showing that apparent competition and the diamond module with and without intraguild predation are ubiquitous, and that weak interactions in simple modules seem to promote less variable population dynamics.

Analysis of Sustainable Development Path for Green Finance

2019 ◽  
pp. 62-83
Author(s):  
Hsu Chao Feng ◽  
Lee Bi Ru
Keyword(s):  
Sustainable Development ◽  
Environmental Protection ◽  
National Development ◽  
Development Project ◽  
Market Society ◽  
Rapid Economic Growth ◽  
Trade Offs ◽  
Green Finance ◽  
The Face ◽  
The Government

The development of green finance is a global trend in the current era. At present, developing the green finance has been included as an important national development project by the Chinese government. With the rapid economic growth, the priorities or trade-offs between the economic development and the natural environment have also aroused different contradictions and problems. With the improvement of people's quality of life, they start to pay more attention to the pollution of the surrounding environment. Therefore, the government should properly intervene and propose effective measures, and green finance is an excellent tool to reconcile social economy and environmental protection and transform the physical investment, thus guiding the social resources towards the environmental protection industry and reaching an optimal interests allocation among the market, society, and government. Consequently, in the face of such a situation, it is necessary to propose a series of models and paths that suit the needs of the Chinese society and promote sustainable development.

scholarly journals Sustainability in the Canadian Egg Industry—Learning from the Past, Navigating the Present, Planning for the Future

2018 ◽  
Vol 10 (10) ◽  
pp. 3524 ◽  
Author(s):  
Nathan Pelletier ◽  
Maurice Doyon ◽  
Bruce Muirhead ◽  
Tina Widowski ◽  
Jodey Nurse-Gupta ◽  
...  
Keyword(s):  
Animal Welfare ◽  
Value Chain ◽  
Housing Systems ◽  
The Past ◽  
Trade Offs ◽  
The Face ◽  
Effective Decision Making ◽  
And Shifts ◽  
Societal Expectations ◽  
Management Changes

Like other livestock sectors, the Canadian egg industry has evolved substantially over time and will likely experience similarly significant change looking forward, with many of these changes determining the sustainability implications of and for the industry. Influencing factors include: technological and management changes at farm level and along the value chain resulting in greater production efficiencies and improved life cycle resource efficiency and environmental performance; a changing policy/regulatory environment; and shifts in societal expectations and associated market dynamics, including increased attention to animal welfare outcomes—especially in regard to changes in housing systems for laying hens. In the face of this change, effective decision-making is needed to ensure the sustainability of the Canadian egg industry. Attention both to lessons from the past and to the emerging challenges that will shape its future is required and multi- and interdisciplinary perspectives are needed to understand synergies and potential trade-offs between alternative courses of action across multiple aspects of sustainability. Here, we consider the past, present and potential futures for this industry through the lenses of environmental, institutional (i.e., regulatory), and socio-economic sustainability, with an emphasis on animal welfare as an important emergent social consideration. Our analysis identifies preferred pathways, potential pitfalls, and outstanding cross-disciplinary research questions.

scholarly journals Efficiency and thoroughness trade-offs in high-volume organisational routines: an ethnographic study of prescribing safety in primary care

2017 ◽  
Vol 27 (3) ◽  
pp. 199-206 ◽  
Author(s):  
Suzanne Grant ◽  
Bruce Guthrie
Keyword(s):  
Primary Care ◽  
Participant Observation ◽  
High Volume ◽  
Ethnographic Study ◽  
Trade Offs ◽  
High Workload ◽  
Organisational Routines ◽  
The Face ◽  
General Practices ◽  
Context Specific

BackgroundPrescribing is a high-volume primary care routine where both speed and attention to detail are required. One approach to examining how organisations approach quality and safety in the face of high workloads is Hollnagel’s Efficiency and Thoroughness Trade-Off (ETTO). Hollnagel argues that safety is aligned with thoroughness and that a choice is required between efficiency and thoroughness as it is not usually possible to maximise both. This study aimed to ethnographically examine the efficiency and thoroughness trade-offs made by different UK general practices in the achievement of prescribing safety.MethodsNon-participant observation was conducted of prescribing routines across eight purposively sampled UK general practices. Sixty-two semistructured interviews were also conducted with key practice staff alongside the analysis of relevant practice documents.ResultsThe eight practices in this study adopted different context-specific approaches to safely handling prescription requests by variably prioritising speed of processing by receptionists (efficiency) or general practitioner (GP) clinical judgement (thoroughness). While it was not possible to maximise both at the same time, practices situated themselves at various points on an efficiency-thoroughness spectrum where one approach was prioritised at particular stages of the routine. Both approaches carried strengths and risks, with thoroughness-focused approaches considered safer but more challenging to implement in practice due to GP workload issues. Most practices adopting efficiency-focused approaches did so out of necessity as a result of their high workload due to their patient population (eg, older, socioeconomically deprived).ConclusionsHollnagel’s ETTO presents a useful way for healthcare organisations to optimise their own high-volume processes through reflection on where they currently prioritise efficiency and thoroughness, the stages that are particularly risky and improved ways of balancing competing priorities.

Evolution of tree killing in bark beetles (Coleoptera: Curculionidae): trade-offs between the maddening crowds and a sticky situation

2013 ◽  
Vol 145 (5) ◽  
pp. 471-495 ◽  
Author(s):  
B.S. Lindgren ◽  
K.F. Raffa
Keyword(s):  
Interspecific Competition ◽  
Bark Beetles ◽  
Life Histories ◽  
Host Defence ◽  
Economic Losses ◽  
Future Research ◽  
Trade Offs ◽  
Wide Range ◽  
Attraction System ◽  
Functional Shift

AbstractBark beetles (Coleoptera: Curculionidae: Scolytinae) play important roles in temperate conifer ecosystems, and also cause substantial economic losses. Although their general life histories are relatively similar, different species vary markedly in the physiological condition of the hosts they select. Most of ∼6000 known species colonise dead or stressed trees, a resource they share with a large diversity of insects and other organisms. A small number of bark beetle species kill healthy, live trees. These few are of particular interest as they compete directly with humans for resources. We propose that tree killing evolved when intense interspecific competition in the ephemeral, scarce resource of defence-impaired trees selected for genotypes that allowed them to escape this limitation by attacking relatively healthy trees. These transitions were uncommon, and we suggest they were facilitated by (a) genetically and phenotypically flexible host selection behaviours, (b) biochemical adaptations for detoxifying a wide range of defence compounds, and (c) associations with symbionts, which together aided bark beetles in overcoming formidable constitutive and induced host defences. The ability to detoxify terpenes influenced the evolutionary course of pheromonal communication. Specifically, a mate attraction system, which was exploited by intraspecific competitors in locating poorly defended hosts, became a system of cooperative attack in which emitters benefit from the contributions responders make in overcoming defence. This functional shift in communication was driven in part by linkage of beetle semiochemistry to host defence chemistry. Behavioural and phenological adaptations also improved the beetles’ abilities to detect when tree defences are impaired, and, where compatible with life history adaptations to other selective forces, for flight to coincide with seasonally predictable host stress agents. We propose a conceptual model, whereby the above mechanisms enable beetles to concentrate on those trees that offer an optimal trade-off between host defence and interspecific competition, along dynamic gradients of tree vigour and stand-level beetle density. We offer suggestions for future research on testing elements of this model.

Catastrophic Climate Change, Precaution, and the Risk/Risk Dilemma

2017 ◽  
Author(s):  
Floor M Fleurke
Keyword(s):  
Climate Change ◽  
Precautionary Principle ◽  
New Technology ◽  
Targeted Intervention ◽  
Regulatory Response ◽  
The Precautionary Principle ◽  
Trade Offs ◽  
The Face

Whilst the seriousness of a given problem may call for immediate and targeted intervention, the ensuing uncertain impacts on other elements of inter-connected systems may be equally deleterious. Climate change is a prime example of such a risk/risk dilemma. The risk of inaction must be weighed against the risk of resorting to increasingly tempting responses to mitigate or adapt to the effects of climate change. The precautionary principle might offer some guidance in this risk/risk arena. Precaution is a tool to deal with uncertain risks without dictating outcomes. Although it is commonly associated with a negative regulatory tilt, it can also serve to warrant and mandate the use of, for example, a new technology or substance in order to reduce risks. This chapter explores the dilemma of risk/risk trade-offs in the face of potentially catastrophic climate change, and examines the contours of a precautionary regulatory response to such impasses.

scholarly journals The nature of nurture in a wild mammal's fitness

2015 ◽  
Vol 282 (1806) ◽  
pp. 20142422 ◽  
Author(s):  
S. Eryn McFarlane ◽  
Jamieson C. Gorrell ◽  
David W. Coltman ◽  
Murray M. Humphries ◽  
Stan Boutin ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Natural Selection ◽  
Maternal Effects ◽  
Adaptive Evolution ◽  
Genetic Effects ◽  
Adaptive Potential ◽  
Red Squirrels ◽  
Trade Offs ◽  
The Face ◽  
North American Red Squirrels

Genetic variation in fitness is required for the adaptive evolution of any trait but natural selection is thought to erode genetic variance in fitness. This paradox has motivated the search for mechanisms that might maintain a population's adaptive potential. Mothers make many contributions to the attributes of their developing offspring and these maternal effects can influence responses to natural selection if maternal effects are themselves heritable. Maternal genetic effects (MGEs) on fitness might, therefore, represent an underappreciated source of adaptive potential in wild populations. Here we used two decades of data from a pedigreed wild population of North American red squirrels to show that MGEs on offspring fitness increased the population's evolvability by over two orders of magnitude relative to expectations from direct genetic effects alone. MGEs are predicted to maintain more variation than direct genetic effects in the face of selection, but we also found evidence of maternal effect trade-offs. Mothers that raised high-fitness offspring in one environment raised low-fitness offspring in another environment. Such a fitness trade-off is expected to maintain maternal genetic variation in fitness, which provided additional capacity for adaptive evolution beyond that provided by direct genetic effects on fitness.

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