scholarly journals A tradeoff between the ecological and evolutionary stabilities of public goods genes in microbial populations

2016 ◽  
Author(s):  
Joseph Rauch ◽  
Jané Kondev ◽  
Alvaro Sanchez
Keyword(s):  
Public Goods ◽  
Evolutionary Stability ◽  
Microbial Populations ◽  
Ecological Stability ◽  
Experimental Conditions ◽  
Regulatory Strategies ◽  
Cooperative Production ◽  
Viable Population ◽  
Population Sizes

Microbial populations often rely on the cooperative production of extracellular public goods molecules. The cooperative nature of public good production may lead to minimum viable population sizes, below which populations collapse. In addition, cooperator public goods producing cells face evolutionary competition from non-producing mutants, or freeloaders. Thus, public goods cooperators have to be stable not only to the invasion of freeloaders, but also to ecological perturbations that may push their numbers too small to be sustainable. Through a combination of experiments with microbial populations and mathematical analysis of the Ecological Public Goods Game, we show that game parameters and experimental conditions that improve the evolutionary stability of cooperators also lead to a low ecological stability of the cooperator population. Complex regulatory strategies mimicking those used by microbes in nature may allow cooperators to beat this eco-evolutionary stability tradeoff and become resistant to freeloaders while at the same time maximizing their ecological stability. Our results thus identify the coupled eco-evolutionary stability as being key for the long-term viability of microbial public goods cooperators.

scholarly journals Cooperators trade off ecological resilience and evolutionary stability in public goods games

2017 ◽  
Vol 14 (127) ◽  
pp. 20160967 ◽  
Author(s):  
Joseph Rauch ◽  
Jane Kondev ◽  
Alvaro Sanchez
Keyword(s):  
Public Goods ◽  
Ecological Resilience ◽  
Trade Off ◽  
Public Goods Games ◽  
Regulatory Strategies ◽  
Cooperative Production ◽  
Key Factor ◽  
Viable Population ◽  
Population Sizes

Microbial populations often rely on the cooperative production of extracellular ‘public goods’ molecules. The cooperative nature of public good production may lead to minimum viable population sizes, below which populations collapse. In addition, ‘cooperator’ public goods producing individuals face evolutionary competition from non-producing mutants, or ‘freeloaders’. Thus, public goods cooperators should be resilient not only to the invasion of freeloaders, but also to ecological perturbations that may push their populations below a sustainable threshold. Through a mathematical analysis of the Ecological Public Goods Game, we show that game parameters that improve the cooperating population's stability to freeloader invasion also lead to a low ecological resilience. Complex regulatory strategies mimicking those used by microbes in nature may allow cooperators to beat this trade-off and become evolutionarily stable to invading freeloaders while at the same time maximizing their ecological resilience. Our results thus identify the coupling between resilience to evolutionary and ecological challenges as a key factor for the long-term viability of public goods cooperators.

scholarly journals Genetic signature of immigrants and their effect on genetic diversity in the recently established Scandinavian wolf population

2021 ◽  
Author(s):  
Mikael Åkesson ◽  
Øystein Flagstad ◽  
Jouni Aspi ◽  
Ilpo Kojola ◽  
Olof Liberg ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Canis Lupus ◽  
Animal Species ◽  
Allelic Richness ◽  
A Priori ◽  
Management Actions ◽  
Viable Population ◽  
Population Sizes ◽  
Source Populations

AbstractTransboundary connectivity is a key component when conserving and managing animal species that require large areas to maintain viable population sizes. Wolves Canis lupus recolonized the Scandinavian Peninsula in the early 1980s. The population is geographically isolated and relies on immigration to not lose genetic diversity and to maintain long term viability. In this study we address (1) to what extent the genetic diversity among Scandinavian wolves has recovered during 30 years since its foundation in relation to the source populations in Finland and Russia, (2) if immigration has occurred from both Finland and Russia, two countries with very different wolf management and legislative obligations to ensure long term viability of wolves, and (3) if immigrants can be assumed to be unrelated. Using 26 microsatellite loci we found that although the genetic diversity increased among Scandinavian wolves (n = 143), it has not reached the same levels found in Finland (n = 25) or in Russia (n = 19). Low genetic differentiation between Finnish and Russian wolves, complicated our ability to determine the origin of immigrant wolves (n = 20) with respect to nationality. Nevertheless, based on differences in allelic richness and private allelic richness between the two countries, results supported the occurrence of immigration from both countries. A priori assumptions that immigrants are unrelated is non-advisable, since 5.8% of the pair-wise analyzed immigrants were closely related. To maintain long term viability of wolves in Northern Europe, this study highlights the potential and need for management actions that facilitate transboundary dispersal.

Distribution and abundance of spectacled hare-wallabies and euros on Barrow Island, Western Australia

1991 ◽  
Vol 18 (4) ◽  
pp. 421 ◽  
Author(s):  
J Short ◽  
B Turner
Keyword(s):  
Population Size ◽  
Total Population ◽  
Empirical Measure ◽  
Habitat Types ◽  
Term Survival ◽  
Significant Difference ◽  
Viable Population ◽  
Population Sizes ◽  
Minimum Viable Population Size

Spectacled hare-wallabies (Lagorchestes conspicillatus) and euros (Macropus robustus isabellinus) occur on Barrow I. at densities of 42 and 8 km-2, respectively, which result in estimates of total population sizes of c. 10000 and 1800, respectively. Spectacled hare-wallabies occur throughout the island in all habitat types; euros tend to be concentrated in the deeply dissected country in the central-west of the island. Limited areas of floodout flats are important feeding areas for euros, being the only major habitat on the island dominated by grasses other than Triodia. There was no significant difference between density of either species on the two halves of the island (one half is dominated by a commercial oilfield; the other is relatively undisturbed). Barrow I. is the smallest island off the Australian coast to have successfully supported a population of large macropods for the 8000-10000 years since separation from the mainland by rising sea-level. Hence, the population estimate of euros on Barrow I. provides an empirical measure of the viable population size necessary for the long-term survival of large macropods. This estimate is nearly two orders of magnitude less than that estimated from a theoretical model of minimum viable population size (Belovsky 1987).

Experimente und forstökonomische Fragen

2012 ◽  
Vol 163 (10) ◽  
pp. 417-421
Author(s):  
Urs Fischbacher
Keyword(s):  
Public Goods ◽  
Experimental Method ◽  
Forest Product ◽  
Time Preferences ◽  
Economic Research ◽  
Timber Production ◽  
Markets And Institutions ◽  
Experimental Findings ◽  
Forest Economic

Experiments and forest economic questions During the last decades experiments have gained great importance in economics. These experiments deal with questions that are of significance for forest economic research, too. Timber production, for example, is characterised by long-term decisions and, in addition, forestry produces important public goods. In this article the experimental method is introduced. Furthermore, experimental findings are presented, e.g., concerning time preferences and externalities, and possible applications for the study of forest product markets and institutions are outlined.

scholarly journals Wood creep data collection and unbiased parameter identification of compliance functions

Holzforschung ◽  
2020 ◽  
Vol 74 (11) ◽  
pp. 1011-1020
Author(s):  
Danyang Tong ◽  
Susan Alexis Brown ◽  
David Corr ◽  
Gianluca Cusatis
Keyword(s):  
Parameter Identification ◽  
Prediction Models ◽  
Tall Buildings ◽  
Building Design ◽  
Parameter Distribution ◽  
Experimental Conditions ◽  
Global Emission ◽  
Wood Construction ◽  
Parameter Values

AbstractRising global emission have led to a renewed popularity of timber in building design, including timber-concrete tall buildings up to 18 stories. In spite of this surge in wood construction, there remains a gap in understanding of long-term structural behavior, particularly wood creep. Unlike concrete, code prescriptions for wood design are lacking in robust estimates for structural shortening. Models for wood creep have become increasingly necessary due to the potential for unforeseen shortening, especially with respect to differential shortening. These effects can have serious impacts as timber building heights continue to grow. This study lays the groundwork for wood compliance prediction models for use in timber design. A thorough review of wood creep studies was conducted and viable experimental results were compiled into a database. Studies were chosen based on correlation of experimental conditions with a realistic building environment. An unbiased parameter identification method, originally applied to concrete prediction models, was used to fit multiple compliance functions to each data curve. Based on individual curve fittings, statistical analysis was performed to determine the best fit function and average parameter values for the collective database. A power law trend in wood creep, with lognormal parameter distribution, was confirmed by the results.

scholarly journals Edaphic factors and plants influence denitrification in soils from a long-term arable experiment

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ian M. Clark ◽  
Qingling Fu ◽  
Maïder Abadie ◽  
Elizabeth R. Dixon ◽  
Aimeric Blaud ◽  
...  
Keyword(s):  
Gas Production ◽  
Soil Treatment ◽  
Soil Microbiome ◽  
Arable Soils ◽  
Experimental Conditions ◽  
Mineral N ◽  
Nitrate Availability ◽  
Denitrification Gene ◽  
Denitrification Genes

Abstract Factors influencing production of greenhouse gases nitrous oxide (N2O) and nitrogen (N2) in arable soils include high nitrate, moisture and plants; we investigate how differences in the soil microbiome due to antecedent soil treatment additionally influence denitrification. Microbial communities, denitrification gene abundance and gas production in soils from tilled arable plots with contrasting fertilizer inputs (no N, mineral N, FYM) and regenerated woodland in the long-term Broadbalk field experiment were investigated. Soil was transferred to pots, kept bare or planted with wheat and after 6 weeks, transferred to sealed chambers with or without K15NO3 fertilizer for 4 days; N2O and N2 were measured daily. Concentrations of N2O were higher when fertilizer was added, lower in the presence of plants, whilst N2 increased over time and with plants. Prior soil treatment but not exposure to N-fertiliser or plants during the experiment influenced denitrification gene (nirK, nirS, nosZI, nosZII) relative abundance. Under our experimental conditions, denitrification generated mostly N2; N2O was around 2% of total gaseous N2 + N2O. Prior long-term soil management influenced the soil microbiome and abundance of denitrification genes. The production of N2O was driven by nitrate availability and N2 generation increased in the presence of plants.

Long-Term Evolutionary Stability of Bacterial Endosymbiosis in Curculionoidea: Additional Evidence of Symbiont Replacement in the Dryophthoridae Family

2008 ◽  
Vol 25 (5) ◽  
pp. 859-868 ◽  
Author(s):  
Cyrille Conord ◽  
Laurence Despres ◽  
Agnès Vallier ◽  
Séverine Balmand ◽  
Christian Miquel ◽  
...  
Keyword(s):  
Evolutionary Stability

scholarly journals Estimating population sizes of lions Panthera leo and spotted hyaenas Crocuta crocuta in Uganda's savannah parks, using lure count methods

Oryx ◽  
2013 ◽  
Vol 48 (3) ◽  
pp. 394-401 ◽  
Author(s):  
Edward Okot Omoya ◽  
Tutilo Mudumba ◽  
Stephen T. Buckland ◽  
Paul Mulondo ◽  
Andrew J. Plumptre
Keyword(s):  
National Parks ◽  
Protected Area ◽  
National Park ◽  
Crocuta Crocuta ◽  
Panthera Leo ◽  
Analysis Method ◽  
Conservation Areas ◽  
Conservation Area ◽  
Population Sizes

AbstractDespite > 60 years of conservation in Uganda's national parks the populations of lions and spotted hyaenas in these areas have never been estimated using a census method. Estimates for some sites have been extrapolated to other protected areas and educated guesses have been made but there has been nothing more definitive. We used a lure count analysis method of call-up counts to estimate populations of the lion Panthera leo and spotted hyaena Crocuta crocuta in the parks where reasonable numbers of these species exist: Queen Elizabeth Protected Area, Murchison Falls Conservation Area and Kidepo Valley National Park. We estimated a total of 408 lions and 324 hyaenas for these three conservation areas. It is unlikely that other conservation areas in Uganda host > 10 lions or > 40 hyaenas. The Queen Elizabeth Protected Area had the largest populations of lions and hyaenas: 140 and 211, respectively. It is estimated that lion numbers have declined by 30% in this protected area since the late 1990s and there are increasing concerns for the long-term viability of both species in Uganda.

scholarly journals Do soil bacterial communities respond differently to abrupt or gradual additions of copper?

2018 ◽  
Vol 95 (1) ◽  
Author(s):  
Michael McTee ◽  
Lorinda Bullington ◽  
Matthias C Rillig ◽  
Philip W Ramsey
Keyword(s):  
Heavy Metals ◽  
Soil Respiration ◽  
Microbial Communities ◽  
Bacterial Communities ◽  
Diversity Indices ◽  
Microbial Populations ◽  
Metal Concentrations ◽  
Soil Bacterial Communities ◽  
Bacterial Richness

ABSTRACTMany experiments that measure the response of microbial communities to heavy metals increase metal concentrations abruptly in the soil. However, it is unclear whether abrupt additions mimic the gradual and often long-term accumulation of these metals in the environment where microbial populations may adapt. In a greenhouse experiment that lasted 26 months, we tested whether bacterial communities and soil respiration differed between soils that received an abrupt or a gradual addition of copper or no copper at all. Bacterial richness and other diversity indices were consistently lower in the abrupt treatment compared to the ambient treatment that received no copper. The abrupt addition of copper yielded different initial bacterial communities than the gradual addition; however, these communities appeared to converge once copper concentrations were approximately equal. Soil respiration in the abrupt treatment was initially suppressed but recovered after four months. Afterwards, respiration in both the gradual and abrupt treatments wavered between being below or equal to the ambient treatment. Overall, our study indicates that gradual and abrupt additions of copper can yield similar bacterial communities and respiration, but these responses may drastically vary until copper concentrations are equal.

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