scholarly journals Frequency-dependent Maternal Effects across Species and Environments

2017 ◽  
Author(s):  
Rachel M. Germain ◽  
Tess N. Grainger ◽  
Natalie T. Jones ◽  
Benjamin Gilbert
Keyword(s):  
Maternal Effects ◽  
Life Histories ◽  
Community Dynamics ◽  
Seed Mass ◽  
List Type ◽  
Frequency Dependent ◽  
Competitive Environments ◽  
Maternal Provisioning ◽  
Population And Community Dynamics ◽  
Maternal Responses

SummaryMaternal provisioning of offspring in response to environmental conditions (“maternal environmental effects”) has been argued as ‘the missing link’ in plant life histories. Although empirical evidence suggests that maternal responses to abiotic conditions are common, there is little understanding of the prevalence of maternal provisioning in competitive environments.We tested how competition in two soil moisture environments affects maternal provisioning of offspring seed mass. Specifically, we varied conspecific frequency from 90% (intraspecific competition) to 10% (interspecific competition) for 15 pairs of annual plant species that occur in California.We found that conspecific frequency affected maternal provisioning (seed mass) in 48% of species, and that these responses included both increased (20%) and decreased (24%) seed mass. In contrast, 68% of species responded to competition through changes in per capita fecundity (seed number), which generally decreased as conspecific frequency increased. The direction and magnitude of frequency-dependent seed mass depended on the identity of the competitor, even among species in which fecundity was not affected by competitor identity.Synthesis. Our research demonstrates how species responses to different competitive environments manifest through maternal provisioning, and that these responses alter previous estimates of environmental maternal effects and reproductive output; future study is needed to understand their combined effects on population and community dynamics.

scholarly journals Dispersal: a central and independent trait in life history

2016 ◽  
Author(s):  
Dries Bonte ◽  
Maxime Dahirel
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Theory ◽  
Community Dynamics ◽  
Evolutionary Dynamics ◽  
Genetic Correlations ◽  
Life History Variation ◽  
Explicit Integration ◽  
Trade Offs ◽  
Population And Community Dynamics

AbstractThe study of trade-offs among major life history components (age at maturity, lifespan and reproduction) allowed the development of a quantitative framework to understand how environmental variation shapes patterns of biodiversity among and within species.Because every environment is inherently spatially structured, and in most cases temporally variable, individuals need to move within and among habitats to maximize fitness. Dispersal is often assumed to be tightly integrated into life histories through genetic correlations with other vital traits. This assumption is particularly strong within the context of a fast-slow continuum of life-history variation. Such a framework is to date used to explain many aspects of population and community dynamics. Evidence for a consistent and context-independent integration of dispersal in life histories is, however, weak. We therefore advocate the explicit integration of dispersal into life history theory as a principal axis of variation influencing fitness, that is free to evolve, independently of other life history traits.We synthesize theoretical and empirical evidence on the central role of dispersal and its evolutionary dynamics on the spatial distribution of ecological strategies and its impact on population spread, invasions and coexistence. By applying an optimality framework we show that the inclusion of dispersal as an independent dimension of life histories might substantially change our view on evolutionary trajectories in spatially structured environments.Because changes in the spatial configuration of habitats affect the costs of movement and dispersal, adaptations to reduce these costs will increase phenotypic divergence among and within populations. We outline how this phenotypic heterogeneity is anticipated to further impact population and community dynamics.

The ecology of parasites of freshwater fishes: the search for patterns

Parasitology ◽  
2009 ◽  
Vol 136 (12) ◽  
pp. 1653-1662 ◽  
Author(s):  
C. R. KENNEDY
Keyword(s):  
Community Dynamics ◽  
Parasite Community ◽  
Freshwater Fishes ◽  
Convincing Evidence ◽  
Helminth Parasites ◽  
Parasite Communities ◽  
Space And Time ◽  
Long Time ◽  
Population And Community Dynamics ◽  
Parasite Populations

SUMMARYDevelopments in the study of the ecology of helminth parasites of freshwater fishes over the last half century are reviewed. Most research has of necessity been field based and has involved the search for patterns in population and community dynamics that are repeatable in space and time. Mathematical models predict that under certain conditions host and parasite populations can attain equilibrial levels through operation of regulatory factors. Such factors have been identified in several host-parasite systems and some parasite populations have been shown to persist over long time-periods. However, there is no convincing evidence that fish parasite populations are stable and regulated since in all cases alternative explanations are equally acceptable and it appears that they are non-equilibrial systems. It has proved particularly difficult to detect replicable patterns in parasite communities. Inter-specific competition, evidenced by functional and numerical responses, has been detected in several communities but its occurrence is erratic and its significance unclear. Some studies have failed to find any nested patterns in parasite community structure and richness, whereas others have identified such patterns although they are seldom constant over space and time. Departures from randomness appear to be the exception and then only temporary. It appears that parasite communities are non-equilibrial, stochastic assemblages rather than structured and organized.

scholarly journals Spatial distribution and survival rate of waterfrog tadpoles in relation to biotic and abiotic factors: a field experiment

2001 ◽  
Vol 22 (1) ◽  
pp. 21-32 ◽  
Author(s):  
Sylvie Thurnheer ◽  
Heinz-Ulrich Reyer
Keyword(s):  
Spatial Distribution ◽  
Community Dynamics ◽  
Abiotic Factors ◽  
Rana Esculenta ◽  
Natural Conditions ◽  
Major Purpose ◽  
Biotic And Abiotic Factors ◽  
Lab Experiments ◽  
Shallow Zone ◽  
Population And Community Dynamics

AbstractPredictions about population and community dynamics are usually based on lab experiments. Because the results are difficult to transfer to natural conditions, the major purpose of this study was to test the effects of biotic and abiotic factors on tadpole populations in a natural environment. We stocked six ponds, created the previous year, with known numbers of Rana esculenta and R. lessonae tadpoles and followed their development over several months. When compared among ponds, tadpole density correlated positively with the nitrate:phosphate ratio. This suggests that water chemistry may have affected survival, either directly or indirectly via productivity. Within ponds, both species showed a clear preference for the shallow zone. This behavior probably reflects a preference for warm water close to the surface, rather than avoidance of predators, because relative densities of odonates also increased from deep to shallow zones. This study is one of few that not only considers the distribution of the anuran tadpoles but the distribution of their predators as well.

scholarly journals Lake sedimentary DNA to reveal long-term changes in aquatic biodiversity and ecosystem functioning

2021 ◽  
Vol 4 ◽  
Author(s):  
Isabelle Domaizon
Keyword(s):  
Community Dynamics ◽  
Temporal Dynamics ◽  
Critical Research ◽  
Aquatic Biodiversity ◽  
Biological Variables ◽  
Long Term Changes ◽  
Research Questions ◽  
Population And Community Dynamics ◽  
Emerging Topics

The emergence of molecular analyses based on the sequencing of sedimentary DNA has opened up many new areas of inquiry in paleolimnology. DNA preserved in sediments (SedDNA) offers the possibility to consider taxa that were traditionally not accessible because they do not leave distinct morphological fossils. Recent applications that considered a diversity of biological groups (including bacteria, protists, zooplankton, fish) illustrate how efficiently SedDNA-based methods complement both classical paleolimnology proxies and limnological data. The knowledge gained from this approach is very diverse in scope, ranging from quantifying natural variability in population and community dynamics to understanding how these biological variables respond to anthropogenic disturbances and climatic change. The use of lake sedimentary DNA to track long-term changes in aquatic biota is a rapidly advancing field of research. Based on recent applications, this presentation illustrates (i) the potential and challenges associated with the study of SedDNA to address critical research questions in lacustrine ecology (ii) the main methodological precautions to be taken into account for implementing these types of DNA analyses (i.e. best practices) and (iii) the emerging topics that could be addressed using sedimentary DNA, in particular to reconstruct the temporal dynamics of lacustrine biodiversity.

scholarly journals Grazing resistance in phytoplankton

Hydrobiologia ◽  
2020 ◽  
Vol 848 (1) ◽  
pp. 237-249 ◽  
Author(s):  
Miquel Lürling
Keyword(s):  
Community Dynamics ◽  
Phytoplankton Community ◽  
Rapid Evolution ◽  
Variable Environment ◽  
Trade Off ◽  
Defense Strategies ◽  
Trade Offs ◽  
Grazing Resistance ◽  
Population And Community Dynamics

AbstractPhytoplankton is confronted with a variable assemblage of zooplankton grazers that create a strong selection pressure for traits that reduce mortality. Phytoplankton is, however, also challenged to remain suspended and to acquire sufficient resources for growth. Consequently, phytoplanktic organisms have evolved a variety of strategies to survive in a variable environment. An overview is presented of the various phytoplankton defense strategies, and costs and benefits of phytoplankton defenses with a zooming in on grazer-induced colony formation. The trade-off between phytoplankton competitive abilities and defenses against grazing favor adaptive trait changes—rapid evolution and phenotypic plasticity—that have the potential to influence population and community dynamics, as exemplified by controlled chemostat experiments. An interspecific defense–growth trade-off could explain seasonal shifts in the species composition of an in situ phytoplankton community yielding defense and growth rate as key traits of the phytoplankton. The importance of grazing and protection against grazing in shaping the phytoplankton community structure should not be underestimated. The trade-offs between nutrient acquisition, remaining suspended, and grazing resistance generate the dynamic phytoplankton community composition.

Evaluation of biodiversity metrics through environmental DNA metabarcoding compared with visual and capture surveys in river fish community

2019 ◽  
Author(s):  
Hideyuki Doi ◽  
Ryutei Inui ◽  
Shunsuke Matsuoka ◽  
Yoshihisa Akamatsu ◽  
Masuji Goto ◽  
...  
Keyword(s):  
Community Dynamics ◽  
Species Turnover ◽  
Environmental Dna ◽  
List Type ◽  
Visual Capture ◽  
Gamma Diversity ◽  
Community Patterns ◽  
Community Assemblages ◽  
Study Sites ◽  
River Fish

AbstractInformation on alpha (local), beta (between habitats), and gamma (regional) diversity is fundamental to understanding biodiversity as well as the function and stability of community dynamics. The methods like environmental DNA (eDNA) metabarcoding are currently considered useful to investigate biodiversity.We compared the performance of eDNA metabarcoding with visual and capture surveys in estimating alpha/gamma diversity and the variation of the community assemblages of river fish communities, particularly considering community nestedness and turnover.In five rivers across west Japan, with comparing to visual/capture surveys, eDNA metabarcoding detected more species in the study sites, consequently the overall number of species in the region (i.e., gamma diversity) was higher. In particular, the species found by visual/capture surveys were encompassed by those by eDNA metabarcoding.With analyzing the community assemblages between the rivers, we showed the different results between the both methods. While, in the same river, the nestedness and species turnover changing from upstream to downstream did not significantly differ between the both methods. Our results suggest that eDNA metabarcoding may be suitable method, especially for understanding regional community patterns, for fish monitoring in rivers.

scholarly journals Employing plant functional groups to advance seed dispersal ecology and conservation

AoB Plants ◽  
2019 ◽  
Vol 11 (2) ◽  
Author(s):  
Clare Aslan ◽  
Noelle G Beckman ◽  
Haldre S Rogers ◽  
Judie Bronstein ◽  
Damaris Zurell ◽  
...  
Keyword(s):  
Seed Dispersal ◽  
Functional Groups ◽  
Community Dynamics ◽  
Single Species ◽  
Plant Functional Groups ◽  
Similar Species ◽  
Seed Dispersal Effectiveness ◽  
Data Collection And Analysis ◽  
Population And Community Dynamics ◽  
Species Specific

Abstract Seed dispersal enables plants to reach hospitable germination sites and escape natural enemies. Understanding when and how much seed dispersal matters to plant fitness is critical for understanding plant population and community dynamics. At the same time, the complexity of factors that determine if a seed will be successfully dispersed and subsequently develop into a reproductive plant is daunting. Quantifying all factors that may influence seed dispersal effectiveness for any potential seed-vector relationship would require an unrealistically large amount of time, materials and financial resources. On the other hand, being able to make dispersal predictions is critical for predicting whether single species and entire ecosystems will be resilient to global change. Building on current frameworks, we here posit that seed dispersal ecology should adopt plant functional groups as analytical units to reduce this complexity to manageable levels. Functional groups can be used to distinguish, for their constituent species, whether it matters (i) if seeds are dispersed, (ii) into what context they are dispersed and (iii) what vectors disperse them. To avoid overgeneralization, we propose that the utility of these functional groups may be assessed by generating predictions based on the groups and then testing those predictions against species-specific data. We suggest that data collection and analysis can then be guided by robust functional group definitions. Generalizing across similar species in this way could help us to better understand the population and community dynamics of plants and tackle the complexity of seed dispersal as well as its disruption.

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