Functional evenness and community-weighted mean traits have strong correlation with macrophyte community productivity

AbstractAcross four grassland habitat types, the cover of thin-leaved plants was found to decrease significantly, but generally only limited trait selection was observed on leaf traits (SLA and LDMC) in a study of an extensive Danish grassland vegetation dataset from an eight-year period. The mostly negative result of this study may partly be due to the relatively conservative analysis, where the continuous plant trait variables are used for grouping plant species into functional types, which are then treated as dependent variables. This procedure is in contrast to most other analyses of trait selection, where it is the community weighted mean of the traits that is used as the dependent variable. However, it is not the traits, but rather individual plants that are sampled and, consequently, it is important to consider the sampling of species abundance in the statistical modelling of plant traits. This misapprehension has not received sufficient proper attention in the plant trait literature.

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Testing the Poleotolerance Lichen Response Trait as an Indicator of Anthropic Disturbance in an Urban Environment

Diversity ◽

10.3390/d11040055 ◽

2019 ◽

Vol 11 (4) ◽

pp. 55 ◽

Cited By ~ 1

Author(s):

Bernardo Rocha ◽

Pedro Pinho ◽

Joana Vieira ◽

Cristina Branquinho ◽

Paula Matos

Keyword(s):

Functional Groups ◽

Urban Environments ◽

Ecological Indicator ◽

Urban Context ◽

Weighted Mean ◽

Environmental Disturbances ◽

Lichen Diversity ◽

Island Effect ◽

Wide Range ◽

Community Weighted Mean

Urban environments are densely populated areas buzzing with a wide range of anthropic activities that cause disturbances like air pollution or the heat island effect, threatening both human and environmental health. Mitigating its impacts implies understanding the integrated effects that those disturbances exert on urban environments. Lichen biodiversity is frequently used as an ecological indicator, being able to integrate its effects in a quantifiable way. The poleotolerance response trait classifies lichens according to their tolerance to human disturbance, but it was developed for Italy’s flora and has seldom been applied outside Italy or in urban context studies. The aim of this work was to assess this trait suitability as an indicator of urban anthropic disturbance and test it outside Italy. For that, we sampled lichen diversity in 41 green spaces in Lisbon. Lichens were classified into the respective poleotolerance trait functional groups and their community weighted mean related with three type of environmental variables used as surrogates of urban disturbance. We showed that disturbance-tolerant functional groups could be used as an ecological indicator of the integrated effects of environmental disturbances. Some species were clearly misclassified, so we propose reclassification for those. Natural and seminatural functional groups did not behave as expected. Nevertheless, disturbance-tolerant functional groups have the potential to be used in in other Southern European cities.

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Community assembly processes along a sub-Mediterranean elevation gradient: analyzing the interdependence of trait community weighted mean and functional diversity

Plant Ecology ◽

10.1007/s11258-019-00985-2 ◽

2019 ◽

Vol 220 (12) ◽

pp. 1139-1151 ◽

Cited By ~ 7

Author(s):

Alessandro Bricca ◽

Luisa Conti ◽

Maria Federico Tardella ◽

Andrea Catorci ◽

Marco Iocchi ◽

...

Keyword(s):

Functional Diversity ◽

Community Assembly ◽

Elevation Gradient ◽

Weighted Mean ◽

Community Weighted Mean

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Explaining variation in productivity requires intraspecific variability in plant height among communities

Journal of Plant Ecology ◽

10.1093/jpe/rtab096 ◽

2021 ◽

Author(s):

Li Zhang ◽

Xiang Liu ◽

Shurong Zhou ◽

Bill Shipley

Keyword(s):

Plant Height ◽

Structural Equation ◽

Functional Group ◽

Intraspecific Variability ◽

Ecosystem Functions ◽

Weighted Mean ◽

Interspecific Variability ◽

Community Weighted Mean ◽

Intraspecific Trait Variability ◽

Trait Variability

Abstract Aims While recent studies have shown the importance of intraspecific trait variation in the processes of community assembly, we still know little about the contributions of intraspecific trait variability to ecosystem functions. Methods Here, we conducted a functional group removal experiment in an alpine meadow in Qinghai-Tibetan Plateau over four years to investigate the relative importance of inter- and intra-specific variability in plant height for productivity. We split total variability in plant height within each of 75 manipulated communities into interspecific variability (TVinter) and intraspecific variability within a community (ITVwithin). Community weighted mean height among communities was decomposed into fixed community weighted mean (CWMfixed) and intraspecific variability among communities (ITVamong). We constructed a series of generalized additive mixed models and piecewise structural equation modelling to determine how trait variability (i.e., TVinter, ITVwithin, CWMfixed and ITVamong) indirectly mediated the changes in productivity in response to functional group removal. Important Findings Community productivity was not only affected directly by treatment manipulations, but also increased with both inter- and intra-specific variability (i.e., CWMfixed, ITVamong) in plant height indirectly. This suggests that both the “selection effect” and a “shade-avoidance syndrome” can incur higher CWMfixed and ITVamong, and may simultaneously operate to regulate productivity. Our findings provide new evidence that, besides interspecific variability, intraspecific trait variability in plant height also plays a role in maintaining net primary productivity.

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Accounting for underlying complexities identifies simple hierarchy of trait‒environment relationships in Wisconsin forest understory communities

10.1101/2020.11.17.387050 ◽

2020 ◽

Author(s):

Andrés G. Rolhauser ◽

Donald M. Waller ◽

Caroline M. Tucker

Keyword(s):

Observational Data ◽

Plant Height ◽

Mixed Model ◽

Environmental Gradients ◽

Functional Structure ◽

Forest Understory ◽

Weighted Mean ◽

Community Weighted Mean ◽

Understory Communities ◽

Positive Effect

AbstractAdaptive relationships between traits and the environment are often inferred from observational data by regressing community-weighted mean (CWM) traits on environmental gradients. However, trait‒environment relationships are better understood as the outcome of trait‒abundance and environment‒abundance relationships, and the interaction between traits and the environment. Accounting for this functional structure and for interrelationships among traits should improve our ability to accurately describe general trait‒environment relationships. Using forest understory communities in Wisconsin, we applied a generalized mixed model (GLMM) incorporating this structure. We identified a simple hierarchy of trait‒environment relationships dominated by a strong positive effect of mean temperature on plant height. Compared to the traditional CWM approach, the GLMM was more conservative in identifying significant trait‒environment relationships, and also detected important relationships that CWM regressions overlooked. This work highlights the need to consider the complexity underlying trait‒environment relationships in future analyses.

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Soil Microbial Community Composition and Diversity Remained Unchanged in a Semiarid Grassland in Northwestern China After 7 Years of Nitrogen Addition

10.21203/rs.3.rs-1105169/v1 ◽

2021 ◽

Author(s):

Qian Guo ◽

Zhongming Wen ◽

Hossein Ghanizadeh ◽

Cheng Zheng ◽

Yongming Fan ◽

...

Keyword(s):

Microbial Community ◽

Soil Properties ◽

Community Composition ◽

Microbial Community Composition ◽

N Deposition ◽

Leaf Nitrogen Content ◽

N Addition ◽

Weighted Mean ◽

Soil Microbial ◽

Community Weighted Mean

Abstract Aims Nitrogen (N) deposition is a global environmental problem that can alter community compositions and functions, and consequently, the ecosystem services. In this study, we assessed the responses of aboveground vegetation, surface soil properties and microbial communities to N addition, and explored the drivers of microbial community in a semiarid steppe ecosystem in northwest of China. Methods Thirty-six 6×10-m2 plots composed of six N addition levels and six replicates were distributed in six columns and six rows. Nine vegetation characteristics and seven soil properties were measured and calculated. Soil microbial characteristics were analyzed by 16S rRNA high-throughput sequencing. Results N addition positively affected aboveground vegetation traits such as the community weighted-mean of leaf nitrogen content (LNCWM). High N inputs significantly altered the microbial community assembly process from random to deterministic. The microbial community diversity and composition, however, were not sensitive to N addition. A piecewise structural equation model (SEM) further showed that the microbial community composition was affected by both aboveground vegetation and soil properties. The composition of bacterial communities was mainly regulated by the composition of plant communities and soil total N. In contrast, the composition of fungal communities was driven by soil pH and the community weighted-mean of specific leaf area (SLACWM). Microbial diversity and composition remained unchanged because their drivers were not affected by N addition. The results of this research improved our understanding of the response of grassland ecosystems to N deposition, and provided a theoretical basis for grassland utilization and management under N deposition.

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On estimating the shape and dynamics of phenotypic distributions in ecology and evolution

10.22541/au.162196147.76797968/v1 ◽

2021 ◽

Author(s):

Brian Maitner ◽

Aud Halbritter ◽

Richard Telford ◽

Tanya Strydom ◽

Julia Chacon-Labella ◽

...

Keyword(s):

Intraspecific Variation ◽

Evolutionary Biology ◽

R Package ◽

Sampling Unit ◽

Weighted Mean ◽

Central Moments ◽

Community Weighted Mean ◽

The Mean ◽

Mean Variance ◽

Skewness And Kurtosis

Estimating the distribution of phenotypes in populations and communities is central to many questions in ecology and evolutionary biology. These distributions can be characterized by their moments: the mean, variance, skewness, and kurtosis. Typically, these moments are calculated using a community-weighted approach (e.g. community-weighted mean) which ignores intraspecific variation. As an alternative, bootstrapping approaches can incorporate intraspecific variation to improve estimates, and also quantify uncertainty in the estimate. Here, we compare the performance of different approaches for estimating the moments of trait distributions across a variety of sampling scenarios, taxa, and datasets. We introduce the traitstrap R package to facilitate inferences of trait distributions via bootstrapping. Our results suggest that randomly sampling ~9 individuals per sampling unit and species, focusing on covering all species in the community, and analysing the data using nonparametric bootstrapping generally enables reliable inference on trait distributions, including the central moments, of communities.

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Community-weighted mean traits but not functional diversity determine the changes in soil properties during wetland drying on the Tibetan Plateau

Solid Earth ◽

10.5194/se-8-137-2017 ◽

2017 ◽

Vol 8 (1) ◽

pp. 137-147 ◽

Cited By ~ 7

Author(s):

Wei Li ◽

Howard E. Epstein ◽

Zhongming Wen ◽

Jie Zhao ◽

Jingwei Jin ◽

...

Keyword(s):

Tibetan Plateau ◽

Soil Properties ◽

Leaf Area ◽

Functional Diversity ◽

Functional Divergence ◽

The Tibetan Plateau ◽

Dry Matter Content ◽

Weighted Mean ◽

Functional Richness ◽

Community Weighted Mean

Abstract. Climate change and human activities have caused a shift in vegetation composition and soil biogeochemical cycles of alpine wetlands on the Tibetan Plateau. The primary goal of this study was to test for associations between community-weighted mean (CWM) traits, functional diversity, and soil properties during wetland drying. We collected soil samples and investigated the aboveground vegetation in swamp, swamp meadow, and typical meadow environments. Four CWM trait values (specific leaf area is SLA, leaf dry matter content is LDMC, leaf area is LA, and mature plant height is MPH) for 42 common species were measured across the three habitats; three components of functional diversity (functional richness, functional evenness, and functional divergence) were also quantified at these sites. Our results showed that the drying of the wetland dramatically altered plant community and soil properties. There was a significant correlation between CWM of traits and soil properties, but not a significant correlation between functional diversity and soil properties. Our results further showed that CWM-LA, CWM-SLA, and CWM-LDMC had positive correlations with soil readily available nutrients (available nitrogen, AN; available phosphorus, AP), but negative correlations with total soil nutrients (soil organic carbon is SOC, total nitrogen is TN, and total phosphorus is TP). Our study demonstrated that simple, quantitative plant functional traits, but not functional diversity, are directly related to soil C and N properties, and they likely play an important role in plant–soil interactions. Our results also suggest that functional identity of species may be more important than functional diversity in influencing ecosystem processes during wetland drying.

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