scholarly journals Genetic diversity increases food-web persistence in the face of climate warming

2020 ◽  
Author(s):  
Matthew A. Barbour ◽  
Daniel J. Kliebenstein ◽  
Jordi Bascompte
Keyword(s):  
Genetic Diversity ◽  
Food Web ◽  
Allelic Variation ◽  
Chemical Defenses ◽  
Trophic Levels ◽  
Raw Material ◽  
Ecological Communities ◽  
Warming Scenario ◽  
The Face ◽  
Loss Of Genetic Diversity

Genetic diversity provides the raw material for species to adapt and persist in the face of climate change. Yet, the extent to which these genetic effects scale at the level of ecological communities remains unclear. Here we experimentally test the effect of plant genetic diversity on the persistence of an insect food web under a current and future warming scenario. We found that plant genetic diversity increased food-web persistence by increasing the intrinsic growth rates of species across multiple trophic levels. This positive effect was robust to a 3°C warming scenario and resulted from allelic variation at two genes that control the biosynthesis of chemical defenses. Our results suggest that the ongoing loss of genetic diversity may undermine the persistence and functioning of ecosystems in a changing world.One Sentence SummaryThe loss of genetic diversity accelerates the extinction of inter-connected species from an experimental food web.

Inbreeding and loss of genetic diversity increase extinction risk

2019 ◽  
pp. 31-48
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Inbreeding Depression ◽  
Environmental Changes ◽  
Extinction Risk ◽  
Raw Material ◽  
Heterozygote Advantage ◽  
Isolated Populations ◽  
Survival And Reproduction ◽  
Loss Of Genetic Diversity ◽  
Harmful Effects

Inbreeding reduces survival and reproduction (i.e. it causes inbreeding depression), and thereby increases extinction risk. Inbreeding depression is due to increased homozygosity for harmful alleles and at loci exhibiting heterozygote advantage. Inbreeding depression is nearly universal in sexually reproducing organisms that are diploid or have higher ploidies. Impacts of inbreeding are generally greater in species that naturally outbreed than those that inbreed, in stressful than benign environments, and for fitness than peripheral traits. Harmful effects accumulate across the life cycle, resulting in devastating effects on total fitness in outbreeding species.Species face ubiquitous environmental change and must adapt or they will go extinct. Genetic diversity is the raw material required for evolutionary adaptation. However, loss of genetic diversity is unavoidable in small isolated populations, diminishing their capacity to evolve in response to environmental changes, and thereby increasing extinction risk.

scholarly journals Food-web dynamics under climate change

2017 ◽  
Vol 284 (1867) ◽  
pp. 20171772 ◽  
Author(s):  
Lai Zhang ◽  
Daisuke Takahashi ◽  
Martin Hartvig ◽  
Ken H. Andersen
Keyword(s):  
Climate Change ◽  
Food Web ◽  
Ecosystem Function ◽  
Trophic Levels ◽  
Physiological Effects ◽  
Ecological Communities ◽  
Temperature Changes ◽  
Thermal Niche ◽  
The Impact ◽  
Food Web Model

Climate change affects ecological communities through its impact on the physiological performance of individuals. However, the population dynamic of species well inside their thermal niche is also determined by competitors, prey and predators, in addition to being influenced by temperature changes. We use a trait-based food-web model to examine how the interplay between the direct physiological effects from temperature and the indirect effects due to changing interactions between populations shapes the ecological consequences of climate change for populations and for entire communities. Our simulations illustrate how isolated communities deteriorate as populations go extinct when the environment moves outside the species' thermal niches. High-trophic-level species are most vulnerable, while the ecosystem function of lower trophic levels is less impacted. Open communities can compensate for the loss of ecosystem function by invasions of new species. Individual populations show complex responses largely uncorrelated with the direct impact of temperature change on physiology. Such complex responses are particularly evident during extinction and invasion events of other species, where climatically well-adapted species may be brought to extinction by the changed food-web topology. Our results highlight that the impact of climate change on specific populations is largely unpredictable, and apparently well-adapted species may be severely impacted.

scholarly journals Species richness and vulnerability to disturbance propagation in real food webs

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Edoardo Calizza ◽  
Loreto Rossi ◽  
Giulio Careddu ◽  
Simona Sporta Caputi ◽  
Maria Letizia Costantini
Keyword(s):  
Species Richness ◽  
Food Web ◽  
Food Webs ◽  
Ecosystem Management ◽  
Food Chains ◽  
Ecological Communities ◽  
Top Down ◽  
Disturbance Propagation ◽  
The Face ◽  
Constant Feeding

AbstractA central issue in ecology is understanding how complex and biodiverse food webs persist in the face of disturbance, and which structural properties affect disturbance propagation among species. However, our comprehension of assemblage mechanisms and disturbance propagation in food webs is limited by the multitude of stressors affecting ecosystems, impairing ecosystem management. By analysing directional food web components connecting species along food chains, we show that increasing species richness and constant feeding linkage density promote the establishment of predictable food web structures, in which the proportion of species co-present in one or more food chains is lower than what would be expected by chance. This reduces the intrinsic vulnerability of real food webs to disturbance propagation in comparison to random webs, and suggests that biodiversity conservation efforts should also increase the potential of ecological communities to buffer top-down and bottom-up disturbance in ecosystems. The food web patterns observed here have not been noticed before, and could also be explored in non-natural networks.

Genetic Analysis of Chinese Cucumber Collections in the U.S. National Germplasm Collection

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 534e-534 ◽  
Author(s):  
J. Staub ◽  
Felix Sequen ◽  
Tom Horejsi ◽  
Jin Feng Chen
Keyword(s):  
Genetic Diversity ◽  
Principal Component Analysis ◽  
Genetic Variation ◽  
Genetic Analysis ◽  
Allelic Variation ◽  
Germplasm Collection ◽  
Principal Component ◽  
Isozyme Loci ◽  
National Plant Germplasm System ◽  
The U.S

Genetic variation in cucumber accessions from China was assessed by examining variation at 21 polymorphic isozyme loci. Principal component analysis of allelic variation allowed for the depiction of two distinct groupings of Chinese accessions collected in 1994 and 1996 (67 accessions). Six isozyme loci (Gpi, Gr, Mdh-2, Mpi-2, Pep-gl, and Pep-la) were important in elucidating these major groups. These groupings were different from a single grouping of Chinese 146 accessions acquired before 1994. Allelic variation in Chinese accessions allowed for comparisons with other accessions in the U.S. National Plant Germplasm System (U.S. NPGS) collection grouped by continent and sub-continent. When Chinese accessions taken collectively were compared with an array of 853 C. sativus U.S. NPGS accessions examined previously, relationships differed between accessions grouped by country or subcontinent. Data indicate that acquisition of additional Chinese and Indian cucumber accessions would be strategically important for increasing genetic diversity in the U.S. NPGS cucumber collection.

Evolutionary genetics of small populations

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Size ◽  
Evolutionary Genetics ◽  
Small Population ◽  
Small Populations ◽  
Effective Population ◽  
Genetic Management ◽  
Evolutionary Genetic ◽  
Loss Of Genetic Diversity ◽  
Number Of Individuals

Genetic management of fragmented populations involves the application of evolutionary genetic theory and knowledge to alleviate problems due to inbreeding and loss of genetic diversity in small population fragments. Populations evolve through the effects of mutation, natural selection, chance (genetic drift) and gene flow (migration). Large outbreeding, sexually reproducing populations typically contain substantial genetic diversity, while small populations typically contain reduced levels. Genetic impacts of small population size on inbreeding, loss of genetic diversity and population differentiation are determined by the genetically effective population size, which is usually much smaller than the number of individuals.

scholarly journals Genetic diversity of high and low molecular weight glutenin subunits in Saharan bread and durum wheats from Algerian oases

2012 ◽  
Vol 48 (No. 1) ◽  
pp. 23-32 ◽  
Author(s):  
I. Bellil ◽  
M. Chekara Bouziani ◽  
D. Khelifi
Keyword(s):  
Genetic Diversity ◽  
Molecular Weight ◽  
Durum Wheat ◽  
Bread Wheat ◽  
Allelic Variation ◽  
Low Molecular Weight ◽  
Glutenin Subunits ◽  
Lmw Glutenin Subunits ◽  
Genotypic Identification ◽  
Diversity Studies

Saharan wheats have been studied particularly from a botanical viewpoint. Genotypic identification, classification and genetic diversity studies to date were essentially based on the morphology of the spike and grain. For this, the allelic variation at the glutenin loci was studied in a set of Saharan bread and durum wheats from Algerian oases where this crop has been traditionally cultivated. The high molecular weight and low molecular weight glutenin subunit composition of 40 Saharan bread and 30 durum wheats was determined by SDS-PAGE. In Saharan bread wheats 32 alleles at the six glutenin loci were detected, which in combination resulted in 36 different patterns including 17 for HMW and 23 for LMW glutenin subunits. For the Saharan durum wheats, 29 different alleles were identified for the five glutenin loci studied. Altogether, 29 glutenin patterns were detected, including 13 for HMW-GS and 20 for LMW-GS. Three new alleles were found in Saharan wheats, two in durum wheat at the Glu-B1 and Glu-B3 loci, and one in bread wheat at the Glu-B1 locus. The mean indices of genetic variation at the six loci in bread wheat and at the five loci in durum wheat were 0.59 and 0.63, respectively, showing that Saharan wheats were more diverse. This information could be useful to select Saharan varieties with improved quality and also as a source of genes to develop new lines when breeding for quality.

scholarly journals Genetic diversity and evolution of hepatitis C virus – 15 years on

2004 ◽  
Vol 85 (11) ◽  
pp. 3173-3188 ◽  
Author(s):  
Peter Simmonds
Keyword(s):  
Genetic Diversity ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Human Liver ◽  
Large Population ◽  
Sequence Divergence ◽  
Selection Pressures ◽  
Host Interactions ◽  
Persistent Viruses ◽  
The Face

In the 15 years since the discovery of hepatitis C virus (HCV), much has been learned about its role as a major causative agent of human liver disease and its ability to persist in the face of host-cell defences and the immune system. This review describes what is known about the diversity of HCV, the current classification of HCV genotypes within the family Flaviviridae and how this genetic diversity contributes to its pathogenesis. On one hand, diversification of HCV has been constrained by its intimate adaptation to its host. Despite the >30 % nucleotide sequence divergence between genotypes, HCV variants nevertheless remain remarkably similar in their transmission dynamics, persistence and disease development. Nowhere is this more evident than in the evolutionary conservation of numerous evasion methods to counteract the cell's innate antiviral defence pathways; this series of highly complex virus–host interactions may represent key components in establishing its ‘ecological niche’ in the human liver. On the other hand, the mutability and large population size of HCV enables it to respond very rapidly to new selection pressures, manifested by immune-driven changes in T- and B-cell epitopes that are encountered on transmission between individuals with different antigen-recognition repertoires. If human immunodeficiency virus type 1 is a precedent, future therapies that target virus protease or polymerase enzymes may also select very rapidly for antiviral-resistant mutants. These contrasting aspects of conservatism and adaptability provide a fascinating paradigm in which to explore the complex selection pressures that underlie the evolution of HCV and other persistent viruses.

scholarly journals All Populations Matter: Conservation Genomics of Australia’s Iconic Purple Wattle, Acacia purpureopetala

Diversity ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 139
Author(s):  
Marlien M. van der Merwe ◽  
Jia-Yee S. Yap ◽  
Peter D. Wilson ◽  
Helen T. Murphy ◽  
Andrew Ford
Keyword(s):  
Genetic Diversity ◽  
Allelic Variation ◽  
Germplasm Conservation ◽  
Snp Markers ◽  
Genomic Diversity ◽  
Ex Situ ◽  
Spatial Distance ◽  
Genetic Connectivity ◽  
Conservation Genomics ◽  
Modelling Framework

Maximising genetic diversity in conservation efforts can help to increase the chances of survival of a species amidst the turbulence of the anthropogenic age. Here, we define the distribution and extent of genomic diversity across the range of the iconic but threatened Acacia purpureopetala, a beautiful sprawling shrub with mauve flowers, restricted to a few disjunct populations in far north Queensland, Australia. Seed production is poor and germination sporadic, but the species occurs in abundance at some field sites. While several thousands of SNP markers were recovered, comparable to other Acacia species, very low levels of heterozygosity and allelic variation suggested inbreeding. Limited dispersal most likely contributed towards the high levels of divergence amongst field sites and, using a generalised dissimilarity modelling framework amongst environmental, spatial and floristic data, spatial distance was found to be the strongest factor explaining the current distribution of genetic diversity. We illustrate how population genomic data can be utilised to design a collecting strategy for a germplasm conservation collection that optimises genetic diversity. For this species, inclusion of all field sites will capture maximum genetic diversity for both in situ and ex situ conservation. Assisted cross pollination, within and between field sites and genetically structured groups, is recommended to enhance heterozygosity particularly at the most disjunct sites and further fragmentation should be discouraged to avoid loss of genetic connectivity.

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