scholarly journals Synchrony matters more than species richness in plant community stability at a global scale

2020 ◽  
Vol 117 (39) ◽  
pp. 24345-24351 ◽  
Author(s):  
Enrique Valencia ◽  
Francesco de Bello ◽  
Thomas Galland ◽  
Peter B. Adler ◽  
Jan Lepš ◽  
...  
Keyword(s):  
Species Richness ◽  
Global Scale ◽  
Environmental Drivers ◽  
Ecological Communities ◽  
Community Stability ◽  
Forage Production ◽  
The Stability ◽  
Random Fluctuations ◽  
Weak Influence ◽  
Analysis Of Time Series

The stability of ecological communities is critical for the stable provisioning of ecosystem services, such as food and forage production, carbon sequestration, and soil fertility. Greater biodiversity is expected to enhance stability across years by decreasing synchrony among species, but the drivers of stability in nature remain poorly resolved. Our analysis of time series from 79 datasets across the world showed that stability was associated more strongly with the degree of synchrony among dominant species than with species richness. The relatively weak influence of species richness is consistent with theory predicting that the effect of richness on stability weakens when synchrony is higher than expected under random fluctuations, which was the case in most communities. Land management, nutrient addition, and climate change treatments had relatively weak and varying effects on stability, modifying how species richness, synchrony, and stability interact. Our results demonstrate the prevalence of biotic drivers on ecosystem stability, with the potential for environmental drivers to alter the intricate relationship among richness, synchrony, and stability.

scholarly journals Relation between stability and resilience determines the performance of early warning signals under different environmental drivers

2015 ◽  
Vol 112 (32) ◽  
pp. 10056-10061 ◽  
Author(s):  
Lei Dai ◽  
Kirill S. Korolev ◽  
Jeff Gore
Keyword(s):  
Early Warning ◽  
Alternative Stable States ◽  
Basin Of Attraction ◽  
Environmental Drivers ◽  
Ecological Communities ◽  
Stable States ◽  
Warning Signals ◽  
Early Warning Signals ◽  
The Stability ◽  
Stability And Resilience

Shifting patterns of temporal fluctuations have been found to signal critical transitions in a variety of systems, from ecological communities to human physiology. However, failure of these early warning signals in some systems calls for a better understanding of their limitations. In particular, little is known about the generality of early warning signals in different deteriorating environments. In this study, we characterized how multiple environmental drivers influence the dynamics of laboratory yeast populations, which was previously shown to display alternative stable states [Dai et al., Science, 2012]. We observed that both the coefficient of variation and autocorrelation increased before population collapse in two slowly deteriorating environments, one with a rising death rate and the other one with decreasing nutrient availability. We compared the performance of early warning signals across multiple environments as “indicators for loss of resilience.” We find that the varying performance is determined by how a system responds to changes in a specific driver, which can be captured by a relation between stability (recovery rate) and resilience (size of the basin of attraction). Furthermore, we demonstrate that the positive correlation between stability and resilience, as the essential assumption of indicators based on critical slowing down, can break down in this system when multiple environmental drivers are changed simultaneously. Our results suggest that the stability–resilience relation needs to be better understood for the application of early warning signals in different scenarios.

Diversity-dependent stability under sowing and nutrient addition: evidence from non-weeded artificial grassland

2019 ◽  
Vol 65 (1-2) ◽  
pp. 1-9
Author(s):  
Xin Yin ◽  
Wei Qi ◽  
GuoZhen Du
Keyword(s):  
Species Richness ◽  
Population Level ◽  
Common Species ◽  
Positive Influence ◽  
Nutrient Addition ◽  
Community Stability ◽  
Species Mixture ◽  
The Stability ◽  
Artificial Grassland ◽  
Total Species

A growing body of evidence from diversity-manipulation and natural studies suggests that the stability of community productivity increases with biodiversity; however, few studies have researched this relationship in a non-weeded grassland. To clarify this issue, we established an artificial grassland in 2003 using three common species, Elymus nutans, Festuca sinensis and Festuca ovina, which included seven different community structures (three monocultures, three two-species mixtures and one three-species mixture based on sown species) and two nutrient addition treatments (non-nutrient addition and nutrient addition). Data was collected over a three-year period (2011–2013). Our results showed that the sowing species modified realized species richness (i.e. the number of total species we observed in a community) and species evenness, but had negligible influences on community- and population-level stability. Furthermore, all of these variables were reduced by nutrient addition. These dynamics did not alter the positive influence of realized species richness on community stability, but restricted the stable effect of evenness because this effect was only significant under nutrient addition condition. The potential mechanisms underlying these processes were statistical averaging and species asynchrony, rather than overyielding effect. Conversely, population stability decreased with realized species richness in non-nutrient addition treatments. We conclude that biodiversity contributed to community- and population-level stability even in non-weeded experiment. This process resulted from different mechanisms that observed in weeded experiments. Further studies in other ecosystems (e.g. aquatic ecosystem) are needed to find a more general conclusion.

scholarly journals Intra-Specific variability in fluctuating environments - mechanisms of impact on species diversity

2019 ◽  
Author(s):  
Bnaya Steinmetz ◽  
Michael Kalyuzhny ◽  
Nadav M. Shnerb
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Numerical Study ◽  
Ecological Communities ◽  
Species Persistence ◽  
Species Population ◽  
Environmental Variations ◽  
Specific Trait ◽  
Portfolio Effect ◽  
The Stability

AbstractRecent studies have found considerable trait variations within species. The effect of such intra-specific trait variability (ITV) on the stability, coexistence and diversity of ecological communities received considerable attention and in many models it was shown to impede coexistence and decrease species diversity. Here we present a numerical study of the effect of genetically inherited ITV on species persistence and diversity in a temporally fluctuating environment. Two mechanisms are identified. First, ITV buffers populations against varying environmental conditions (portfolio effect) and reduces abundance variations. Second, the interplay between ITV and environmental variations tends to increase the mean fitness of diverse populations. The first mechanism promotes persistence and tends to increase species richness, while the second reduces the chance of a rare species population (which is usually homogenous) to invade and decreases species richness. We show that for large communities the portfolio effect is dominant, leading to ITV promoting species persistence and richness.

scholarly journals Species delimitation at a global scale reveals high species richness with complex biogeography and patterns of symbiont association in Peltigera section Peltigera (lichenized Ascomycota: Lecanoromycetes)

Taxon ◽  
2018 ◽  
Vol 67 (5) ◽  
pp. 836-870 ◽  
Author(s):  
Nicolas Magain ◽  
Camille Tniong ◽  
Trevor Goward ◽  
Dongling Niu ◽  
Bernard Goffinet ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Delimitation ◽  
Global Scale ◽  
High Species Richness

Ecology of moss-dwelling rotifers in a raised bog: Differentiation of rotifer communities in microhabitats

Biologia ◽  
2017 ◽  
Vol 72 (2) ◽  
Author(s):  
Irena Bielańska-Grajner ◽  
Tomasz Mieczan ◽  
Anna Cieplok
Keyword(s):  
Species Richness ◽  
Moisture Content ◽  
Dominant Species ◽  
Peat Bogs ◽  
Raised Bog ◽  
Ecological Relationships ◽  
Seasonal Factors ◽  
The Stability ◽  
Endangered Ecosystems ◽  
Rotifer Communities

AbstractPeat bogs play key roles in preserving the stability of ecological relationships, but are some of the fastest disappearing and most endangered ecosystems in Europe. The aims of this study were: (1) to compare the distribution, species richness, diversity, and density of rotifers in microhabitats of a raised bog; and (2) to verify the hypothesis that rotifer density and species composition are dependent on seasonal factors, moss moisture content, and the dominant species of mosses in the microhabitats. Sampling was done monthly from April to November in 2013–2014 in the bog Moszne in eastern Poland (51°27′28.7″ N, 23°07′15.8″ E). The microhabitats sampled included hummocks, slopes, and hollows. A total of 40 rotifer taxa were identified. The highest species richness occurred in the hollows (40), dominated by

scholarly journals Scavenging in the Anthropocene: Human impact drives vertebrate scavenger species richness at a global scale

2020 ◽  
Author(s):  
E Sebastián-González ◽  
JM Barbosa ◽  
JM Pérez-García ◽  
Z Morales-Reyes ◽  
F Botella ◽  
...  
Keyword(s):  
Species Richness ◽  
Human Impact ◽  
Large Scale ◽  
Diversity Index ◽  
Global Scale ◽  
Climatic Conditions ◽  
Ecosystem Functions ◽  
Number Of Species ◽  
Terrestrial Vertebrate ◽  
Latitudinal Patterns

© 2019 John Wiley & Sons Ltd Understanding the distribution of biodiversity across the Earth is one of the most challenging questions in biology. Much research has been directed at explaining the species latitudinal pattern showing that communities are richer in tropical areas; however, despite decades of research, a general consensus has not yet emerged. In addition, global biodiversity patterns are being rapidly altered by human activities. Here, we aim to describe large-scale patterns of species richness and diversity in terrestrial vertebrate scavenger (carrion-consuming) assemblages, which provide key ecosystem functions and services. We used a worldwide dataset comprising 43 sites, where vertebrate scavenger assemblages were identified using 2,485 carcasses monitored between 1991 and 2018. First, we evaluated how scavenger richness (number of species) and diversity (Shannon diversity index) varied among seasons (cold vs. warm, wet vs. dry). Then, we studied the potential effects of human impact and a set of macroecological variables related to climatic conditions on the scavenger assemblages. Vertebrate scavenger richness ranged from species-poor to species rich assemblages (4–30 species). Both scavenger richness and diversity also showed some seasonal variation. However, in general, climatic variables did not drive latitudinal patterns, as scavenger richness and diversity were not affected by temperature or rainfall. Rainfall seasonality slightly increased the number of species in the community, but its effect was weak. Instead, the human impact index included in our study was the main predictor of scavenger richness. Scavenger assemblages in highly human-impacted areas sustained the smallest number of scavenger species, suggesting human activity may be overriding other macroecological processes in shaping scavenger communities. Our results highlight the effect of human impact at a global scale. As species-rich assemblages tend to be more functional, we warn about possible reductions in ecosystem functions and the services provided by scavengers in human-dominated landscapes in the Anthropocene.

scholarly journals Maturation of UTR-Derived sRNAs Is Modulated during Adaptation to Different Growth Conditions

2021 ◽  
Vol 22 (22) ◽  
pp. 12260
Author(s):  
Daniel-Timon Spanka ◽  
Gabriele Klug
Keyword(s):  
Growth Conditions ◽  
Global Scale ◽  
Rnase E ◽  
Bacterial Gene ◽  
Ribonuclease E ◽  
Mrna Targets ◽  
Small Regulatory Rnas ◽  
The Stability ◽  
Ngs Data

Small regulatory RNAs play a major role in bacterial gene regulation by binding their target mRNAs, which mostly influences the stability or translation of the target. Expression levels of sRNAs are often regulated by their own promoters, but recent reports have highlighted the presence and importance of sRNAs that are derived from mRNA 3′ untranslated regions (UTRs). In this study, we investigated the maturation of 5′ and 3′ UTR-derived sRNAs on a global scale in the facultative phototrophic alphaproteobacterium Rhodobacter sphaeroides. Including some already known UTR-derived sRNAs like UpsM or CcsR1-4, 14 sRNAs are predicted to be located in 5′ UTRs and 16 in 3′ UTRs. The involvement of different ribonucleases during maturation was predicted by a differential RNA 5′/3′ end analysis based on RNA next generation sequencing (NGS) data from the respective deletion strains. The results were validated in vivo and underline the importance of polynucleotide phosphorylase (PNPase) and ribonuclease E (RNase E) during processing and maturation. The abundances of some UTR-derived sRNAs changed when cultures were exposed to external stress conditions, such as oxidative stress and also during different growth phases. Promoter fusions revealed that this effect cannot be solely attributed to an altered transcription rate. Moreover, the RNase E dependent cleavage of several UTR-derived sRNAs varied significantly during the early stationary phase and under iron depletion conditions. We conclude that an alteration of ribonucleolytic processing influences the levels of UTR-derived sRNAs, and may thus indirectly affect their mRNA targets.

scholarly journals Dynamic population stage structure due to juvenile–adult asymmetry stabilizes complex ecological communities

2021 ◽  
Vol 118 (21) ◽  
pp. e2023709118
Author(s):  
André M. de Roos
Keyword(s):  
Self Regulation ◽  
Interaction Network ◽  
Population Level ◽  
Stage Structure ◽  
Current Theory ◽  
Species Interaction ◽  
Interaction Matrix ◽  
Foraging Efficiency ◽  
Ecological Communities ◽  
The Stability

Natural ecological communities are diverse, complex, and often surprisingly stable, but the mechanisms underlying their stability remain a theoretical enigma. Interactions such as competition and predation presumably structure communities, yet theory predicts that complex communities are stable only when species growth rates are mostly limited by intraspecific self-regulation rather than by interactions with resources, competitors, and predators. Current theory, however, considers only the network topology of population-level interactions between species and ignores within-population differences, such as between juvenile and adult individuals. Here, using model simulations and analysis, I show that including commonly observed differences in vulnerability to predation and foraging efficiency between juvenile and adult individuals results in up to 10 times larger, more complex communities than observed in simulations without population stage structure. These diverse communities are stable or fluctuate with limited amplitude, although in the model only a single basal species is self-regulated, and the population-level interaction network is highly connected. Analysis of the species interaction matrix predicts the simulated communities to be unstable but for the interaction with the population-structure subsystem, which completely cancels out these instabilities through dynamic changes in population stage structure. Common differences between juveniles and adults and fluctuations in their relative abundance may hence have a decisive influence on the stability of complex natural communities and their vulnerability when environmental conditions change. To explain community persistence, it may not be sufficient to consider only the network of interactions between the constituting species.

scholarly journals A global comparison of grassland biomass responses to CO 2 and nitrogen enrichment

2010 ◽  
Vol 365 (1549) ◽  
pp. 2047-2056 ◽  
Author(s):  
Mark Lee ◽  
Pete Manning ◽  
Janna Rist ◽  
Sally A. Power ◽  
Charles Marsh
Keyword(s):  
Large Scale ◽  
Meta Analysis ◽  
C Sequestration ◽  
Global Scale ◽  
Scale Model ◽  
Published Data ◽  
Climate Data ◽  
Forage Production ◽  
Global Comparison ◽  
N Enrichment

Grassland ecosystems cover vast areas of the Earth's surface and provide many ecosystem services including carbon (C) storage, biodiversity preservation and the production of livestock forage. Predicting the future delivery of these services is difficult, because widespread changes in atmospheric CO 2 concentration, climate and nitrogen (N) inputs are expected. We compiled published data from global change driver manipulation experiments and combined these with climate data to assess grassland biomass responses to CO 2 and N enrichment across a range of climates. CO 2 and N enrichment generally increased aboveground biomass (AGB) but effects of CO 2 enrichment were weaker than those of N. The response to N was also dependent on the amount of N added and rainfall, with a greater response in high precipitation regions. No relationship between response to CO 2 and climate was detected within our dataset, thus suggesting that other site characteristics, e.g. soils and plant community composition, are more important regulators of grassland responses to CO 2 . A statistical model of AGB response to N was used in conjunction with projected N deposition data to estimate changes to future biomass stocks. This highlighted several potential hotspots (e.g. in some regions of China and India) of grassland AGB gain. Possible benefits for C sequestration and forage production in these regions may be offset by declines in plant biodiversity caused by these biomass gains, thus necessitating careful management if ecosystem service delivery is to be maximized. An approach such as ours, in which meta-analysis is combined with global scale model outputs to make large-scale predictions, may complement the results of dynamic global vegetation models, thus allowing us to form better predictions of biosphere responses to environmental change.

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