scholarly journals Consumer sexual dimorphism promotes coexistence among competing resources

2019 ◽  
Author(s):  
Stephen P. De Lisle ◽  
Gonzalo Hernando ◽  
Daniel I. Bolnick
Keyword(s):  
Sexual Dimorphism ◽  
Species Interactions ◽  
Natural Populations ◽  
Salient Feature ◽  
Apparent Competition ◽  
Species Variation ◽  
Ecological Communities ◽  
Key Factor ◽  
Classical Models ◽  
Resource Dynamics

AbstractWithin-species variation is a salient feature of natural populations, of substantial importance for species interactions. However, the community consequences of sexual dimorphism, one of the most ubiquitous sources of within-species variance, remains poorly understood. Here, we extend classical models of consumer-resource dynamics to explore the ecological consequences of consumer sexual dimorphism. We show that sexual dimorphism in consumer attack rates on two different resource species promotes coexistence between those resources, mitigating the effects of both apparent competition and direct interspecific competition. Consumer sexual dimorphism can prevent exclusion of a resource with inferior growth rates because reduction in any of the two resources reduces consumer density, generating negative frequency dependence that stabilizes coexistence between resources. Our work highlights ecological sex differences as a potentially key factor governing the assembly of ecological communities, illustrating that the specific source of within-species variance can have important implications for community ecology.

scholarly journals Sexual dimorphism in a top predator ( Notophthalmus viridescens ) drives aquatic prey community assembly

2018 ◽  
Vol 285 (1890) ◽  
pp. 20181717 ◽  
Author(s):  
Denon Start ◽  
Stephen De Lisle
Keyword(s):  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Intraspecific Variation ◽  
Structure And Function ◽  
Sexually Dimorphic ◽  
Ecological Communities ◽  
Top Predator ◽  
Aquatic Mesocosms ◽  
And Function ◽  
The Impact

Intraspecific variation can have important consequences for the structure and function of ecological communities, and serves to link community ecology to evolutionary processes. Differences between the sexes are an overwhelmingly common form of intraspecific variation, but its community-level consequences have never been experimentally investigated. Here, we manipulate the sex ratio of a sexually dimorphic predacious newt in aquatic mesocosms, then track their impact on prey communities. Female and male newts preferentially forage in the benthic and pelagic zones, respectively, causing corresponding reductions in prey abundances in those habitats. Sex ratio differences also explained a large proportion (33%) of differences in the composition of entire pond communities. Ultimately, we demonstrate the impact of known patterns of sexual dimorphism in a predator on its prey, uncovering overlooked links between evolutionary adaptation and the structure of contemporary communities. Given the extreme prevalence of sexual dimorphism, we argue that the independent evolution of the sexes will often have important consequences for ecological communities.

Modelling mutual interactions between soil structure and soil biological communities.

2021 ◽  
Author(s):  
Tancredi Caruso
Keyword(s):  
Habitat Structure ◽  
Soil Structure ◽  
Pore Space ◽  
Point Of View ◽  
Species Number ◽  
Ecological Communities ◽  
Soil Organisms ◽  
Biological Communities ◽  
Key Factor ◽  
Complex Habitat

<p>Habitat structure is a key factor controlling the structure of ecological communities. For example, complex habitat structure may increase species number, minimise competition and facilitate the retention of nutrients. Alteration and disturbance of habitat structure may thus negatively affect biodiversity. Soil is an extremely complex and highly structured environmental matrix. Soil structure, defined as a distribution of aggregate/pore space of different sizes, can thus be a major control of soil biological communities, which are for example highly structured in their size distribution. Soil organisms, however, also affect and modify soil structure, and for many organisms the soil habitat structure is thus not just a condition to which they have to adapt but, rather, an environmental feature they also affect. In this talk, I discuss all these aspects from a community ecology point of view and with an emphasis on statistical and dynamical models that soil ecologists are trying to develop to describe and predict the mutual interactions between soil structure and biological communities. I will focus on the different rates at which soil structure affects soil organisms and vice versa, to emphasise that the temporal scales at which we have to measure the two parts of this mutual feedback (i.e. soil structure -> biota vs. biota -> soil structure) are very different, and also variable in space and time. </p>

The Community of Ecological Opportunities

2017 ◽  
Author(s):  
Mark A. McPeek
Keyword(s):  
Plant Species ◽  
Resource Availability ◽  
Intraguild Predation ◽  
Species Interactions ◽  
Apparent Competition ◽  
Predation Pressure ◽  
Trophic Levels ◽  
Model Species ◽  
Pollinator Species ◽  
Different Types

This chapter examines ecological opportunities that are available to species in various positions within a biological community, with particular emphasis on identifying the criteria necessary for an ecological opportunity to exist. Before discussing what performance capabilities a species must have to fill different types of ecological opportunities and what is required for invasibility of species into different functional positions in a community, the chapter considers the different frameworks that have been used to model species interactions. It then describes resource and apparent competition to show how resource availability from below and predation pressure from above can affect the types of species that can exploit specifc ecological opportunities. It also analyzes communities with three trophic levels, intraguild predation or omnivory, mutualism, the mechanisms that foster coexistence between one plant species and one pollinator species, and the case of one plant species with multiple pollinators.

scholarly journals The Temporal Dynamics of Background Selection in Nonequilibrium Populations

Genetics ◽  
2020 ◽  
Vol 214 (4) ◽  
pp. 1019-1030 ◽  
Author(s):  
Raul Torres ◽  
Markus G. Stetter ◽  
Ryan D. Hernandez ◽  
Jeffrey Ross-Ibarra
Keyword(s):  
Natural Selection ◽  
Temporal Dynamics ◽  
Direct Action ◽  
Demographic History ◽  
Empirical Studies ◽  
Natural Populations ◽  
Background Selection ◽  
Size Change ◽  
Demographic Models ◽  
Classical Models

Neutral genetic diversity across the genome is determined by the complex interplay of mutation, demographic history, and natural selection. While the direct action of natural selection is limited to functional loci across the genome, its impact can have effects on nearby neutral loci due to genetic linkage. These effects of selection at linked sites, referred to as genetic hitchhiking and background selection (BGS), are pervasive across natural populations. However, only recently has there been a focus on the joint consequences of demography and selection at linked sites, and some empirical studies have come to apparently contradictory conclusions as to their combined effects. To understand the relationship between demography and selection at linked sites, we conducted an extensive forward simulation study of BGS under a range of demographic models. We found that the relative levels of diversity in BGS and neutral regions vary over time and that the initial dynamics after a population size change are often in the opposite direction of the long-term expected trajectory. Our detailed observations of the temporal dynamics of neutral diversity in the context of selection at linked sites in nonequilibrium populations provide new intuition about why patterns of diversity under BGS vary through time in natural populations and help reconcile previously contradictory observations. Most notably, our results highlight that classical models of BGS are poorly suited for predicting diversity in nonequilibrium populations.

scholarly journals My niche: individual spatial niche specialization affects within- and between-species interactions

2020 ◽  
Vol 287 (1918) ◽  
pp. 20192211 ◽  
Author(s):  
Annika Schirmer ◽  
Julia Hoffmann ◽  
Jana A. Eccard ◽  
Melanie Dammhahn
Keyword(s):  
Species Interactions ◽  
Community Dynamics ◽  
Species Coexistence ◽  
Myodes Glareolus ◽  
Ecological Niches ◽  
Species Variation ◽  
Interaction Patterns ◽  
Spatial Interactions ◽  
Interindividual Differences ◽  
Niche Specialization

Intraspecific trait variation is an important determinant of fundamental ecological interactions. Many of these interactions are mediated by behaviour. Therefore, interindividual differences in behaviour should contribute to individual niche specialization. Comparable with variation in morphological traits, behavioural differentiation between individuals should limit similarity among competitors and thus act as a mechanism maintaining within-species variation in ecological niches and facilitating species coexistence. Here, we aimed to test whether interindividual differences in boldness covary with spatial interactions within and between two ecologically similar, co-occurring rodent species ( Myodes glareolus , Apodemus agrarius ). In five subpopulations in northeast Germany, we quantified individual differences in boldness via repeated standardized tests and spatial interaction patterns via capture–mark–recapture ( n = 126) and automated VHF telemetry ( n = 36). We found that boldness varied with space use in both species. Individuals of the same population occupied different spatial niches, which resulted in non-random patterns of within- and between-species spatial interactions. Behavioural types mainly differed in the relative importance of intra- versus interspecific competition. Within-species variation along this competition gradient could contribute to maintaining individual niche specialization. Moreover, behavioural differentiation between individuals limits similarity among competitors, which might facilitate the coexistence of functionally equivalent species and, thus, affect community dynamics and local biodiversity.

Natural stressors and disease risk: does the threat of predation increase amphibian susceptibility to ranavirus?

2012 ◽  
Vol 90 (7) ◽  
pp. 893-902 ◽  
Author(s):  
N.A. Haislip ◽  
J.T. Hoverman ◽  
D.L. Miller ◽  
M.J. Gray
Keyword(s):  
Predation Risk ◽  
Stress Responses ◽  
Species Interactions ◽  
Disease Risk ◽  
Natural Populations ◽  
Emerging Infectious Diseases ◽  
Host Susceptibility ◽  
Continuous Exposure ◽  
Amphibian Species ◽  
Predator Cues

Emerging infectious diseases have been identified as threats to biodiversity, yet our understanding of the factors contributing to host susceptibility to pathogens within natural populations remains limited. It has been proposed that species interactions within communities affect host susceptibility to pathogens, thereby contributing to disease emergence. In particular, predation risk is a common natural stressor that has been hypothesized to compromise immune function of prey through chronic stress responses possibly leading to increased susceptibility to pathogens. We examined whether predation risk experienced during the development of four larval anuran species increases susceptibility (mortality and infection) to ranaviruses, a group of viruses responsible for amphibian die-offs. Using controlled laboratory experiments, we exposed each species to a factorial combination of two virus treatments (no virus or virus) crossed with three predator-cue treatments (no predators, larval dragonflies, or adult water bugs). All four amphibian species reduced activity by 22%–48% following continuous exposure to predator cues. In addition, virus exposure significantly reduced survival by 17%–100% across all species. However, exposure to predator cues did not interact with the virus treatments to elevate mortality or viral load. Our results suggest that the expression of predator-induced plasticity in anuran larvae does not increase ranaviral disease risk.

scholarly journals The macroecology of rapid evolutionary radiation

2011 ◽  
Vol 278 (1717) ◽  
pp. 2486-2494 ◽  
Author(s):  
Nicholas F. Parnell ◽  
J. Todd Streelman
Keyword(s):  
Adaptive Radiation ◽  
Species Interactions ◽  
Spatial Scales ◽  
Ecological Communities ◽  
Core Set ◽  
Evolutionary Radiation ◽  
Local Species ◽  
Entire Lake ◽  
Insight Into ◽  
Occurrence Of Species

A long-standing debate in ecology addresses whether community composition is the result of stochastic factors or assembly rules. Non-random, over-dispersed patterns of species co-occurrence have commonly been attributed to competition—a particularly important force in adaptive radiation. We thus examined the macroecology of the recently radiated cichlid rock-fish assemblage in Lake Malawi, Africa at a spectrum of increasingly fine spatial scales (entire lake to depth within rock-reef sites). Along this range of spatial scales, we observed a signal of community structure (decreased co-occurrence of species) at the largest and smallest scales, but not in between. Evidence suggests that the lakewide signature of structure is driven by extreme endemism and micro-allopatric speciation, while patterns of reduced co-occurrence with depth are indicative of species interactions. We identified a ‘core’ set of rock-reef species, found in combination throughout the lake, whose depth profiles exhibited replicated positive and negative correlation. Our results provide insight into how ecological communities may be structured differently at distinct spatial scales, re-emphasize the importance of local species interactions in community assembly, and further elucidate the processes shaping speciation in this model adaptive radiation.

scholarly journals The DNA of coral reef biodiversity: predicting and protecting genetic diversity of reef assemblages

2016 ◽  
Vol 283 (1829) ◽  
pp. 20160354 ◽  
Author(s):  
Kimberly A. Selkoe ◽  
Oscar E. Gaggiotti ◽  
Eric A. Treml ◽  
Johanna L. K. Wren ◽  
Mary K. Donovan ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Species Interactions ◽  
Allelic Richness ◽  
Coral Cover ◽  
Species Turnover ◽  
Depth Range ◽  
Ecological Communities ◽  
Effective Population ◽  
A Site ◽  
New Strategies

Conservation of ecological communities requires deepening our understanding of genetic diversity patterns and drivers at community-wide scales. Here, we use seascape genetic analysis of a diversity metric, allelic richness (AR), for 47 reef species sampled across 13 Hawaiian Islands to empirically demonstrate that large reefs high in coral cover harbour the greatest genetic diversity on average. We found that a species's life history (e.g. depth range and herbivory) mediates response of genetic diversity to seascape drivers in logical ways. Furthermore, a metric of combined multi-species AR showed strong coupling to species richness and habitat area, quality and stability that few species showed individually. We hypothesize that macro-ecological forces and species interactions, by mediating species turnover and occupancy (and thus a site's mean effective population size), influence the aggregate genetic diversity of a site, potentially allowing it to behave as an apparent emergent trait that is shaped by the dominant seascape drivers. The results highlight inherent feedbacks between ecology and genetics, raise concern that genetic resilience of entire reef communities is compromised by factors that reduce coral cover or available habitat, including thermal stress, and provide a foundation for new strategies for monitoring and preserving biodiversity of entire reef ecosystems.

Exploration of sexual dimorphism of Taxus baccata L. needles in natural populations

Trees ◽  
2017 ◽  
Vol 31 (5) ◽  
pp. 1697-1710 ◽  
Author(s):  
Milena Stefanović ◽  
Biljana Nikolić ◽  
Rada Matić ◽  
Zorica Popović ◽  
Vera Vidaković ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Natural Populations ◽  
Taxus Baccata
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