scholarly journals Trait-Based Investigation Reveals Patterns of Community Response to Nutrient Enrichment in Coastal Mesic Grassland

Diversity ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 19
Author(s):  
Joseph K. Brown ◽  
Julie C. Zinnert
Keyword(s):  
Nutrient Enrichment ◽  
Species Abundance ◽  
Alpha Diversity ◽  
Functional Trait ◽  
Community Response ◽  
Abundance Patterns ◽  
Coastal Plant ◽  
And Function ◽  
Atlantic Coastal ◽  
Nitrogen Phosphorus

Despite recent advances, we still do not understand how chronic nutrient enrichment impacts coastal plant community structure and function. We aimed to clarify such impacts by testing for differences in ecosystem productivity and multiple community metrics in response to fertilization. We established plots in 2015 consisting of control (C), nitrogen (N), phosphorus (P), and nitrogen + phosphorus (NP) treatments in a mid-Atlantic coastal grassland. In 2017 we collected aboveground biomass, functional traits, and species abundance for each plot. Our findings indicate a synergistic co-limitation, such that NP plots were more productive than all other treatments. A combination of traits responsible for competition and nutrient uptake (i.e., height and δ15N) caused trait-based divergence of N and NP plots from C and P plots. Functional trait-based composition patterns differed from species composition and lifeform abundance patterns, highlighting complexities of community response to nutrient enrichment. While trait-based functional alpha-diversity did not differ among nutrient treatments, it was positively correlated with biomass production, suggesting nutrients may impact functional alpha-diversity indirectly through increased productivity. Increased functional alpha-diversity could be a mechanism of co-existence emerging as productivity increases. These results have important implications for understanding how plant communities in low-productivity coastal systems are altered by fertilization.

Species abundance patterns of plants in Swedish semi-natural pastures

Ecography ◽  
1995 ◽  
Vol 18 (3) ◽  
pp. 310-317 ◽  
Author(s):  
Asa Eriksson ◽  
Ove Eriksson ◽  
Hans Berglund
Keyword(s):  
Species Abundance ◽  
Abundance Patterns

Do predaceous stoneflies and siltation affect the structure of stream insect communities colonizing enclosures?

1985 ◽  
Vol 63 (7) ◽  
pp. 1519-1530 ◽  
Author(s):  
Barbara L. Peckarsky
Keyword(s):  
New York ◽  
Species Richness ◽  
Prey Species ◽  
Species Abundance ◽  
Benthic Invertebrate ◽  
Taxonomic Composition ◽  
Community Response ◽  
Insect Communities ◽  
Composite Effect ◽  
Benthic Invertebrate Community

Experiments in Colorado and New York streams assessed the effects of predaceous stoneflies on benthic invertebrate community establishment in enclosures providing uncolonized habitat. Aspects of prey community structure measured were density, species richness, relative species abundance, and body size. Unexpected inorganic sediment deposition allowed evaluation of direct effects on Colorado stream benthos and indirect effects on predation. Predaceous perlids and perlodids consistently reduced the density and, therefore, rate of prey community establishment in enclosures. Although New York perlids disproportionately reduced densities of some prey species, Colorado stoneflies caused nonsignificant declines in individual prey species densities, the composite effect of which was a significant whole-community response. Predators did not affect prey species richness nor change the taxonomic composition (species additions or deletions) of communities colonizing enclosures. However, the relative abundance of prey taxa differed significantly between cages with and without predators. Most species showed no size differences between individuals colonizing enclosures with predators and those colonizing control enclosures, with a few interesting exceptions. The deposition of silt eliminated the predator effects on prey density, as well as directly causing significant reductions in many Colorado benthic populations. This result demonstrates that abiotic disturbances can periodically override the effects of predation on stream insect communities colonizing enclosures.

scholarly journals Variation Patterns of Functional Trait Moments Along Geographical Gradients and Their Environmental Determinants in the Subtropical Evergreen Broadleaved Forests

2021 ◽  
Vol 12 ◽  
Author(s):  
Caishuang Huang ◽  
Yue Xu ◽  
Runguo Zang
Keyword(s):  
Climate Variability ◽  
Leaf Area ◽  
Functional Traits ◽  
Specific Leaf Area ◽  
Functional Trait ◽  
Leaf Nitrogen ◽  
Subtropical Region ◽  
Mean Variance ◽  
Nitrogen Phosphorus ◽  
Skewness And Kurtosis

Understanding how environmental change alters the composition of plant assemblages is a major challenge in the face of global climate change. Researches accounting for site-specific trait values within forest communities help bridge plant economics theory and functional biogeography to better evaluate and predict relationships between environment and ecosystem functioning. Here, by measuring six functional traits (specific leaf area, leaf dry matter content, leaf nitrogen, and phosphorus concentration, leaf nitrogen/phosphorus, wood density) for 292 woody plant species (48,680 individuals) from 250 established permanent forest dynamics plots in five locations across the subtropical evergreen broadleaved forests (SEBLF) in China, we quantified functional compositions of communities by calculating four trait moments, i.e., community-weighted mean, variance, skewness, and kurtosis. The geographical (latitudinal, longitudinal, and elevational) patterns of functional trait moments and their environmental drivers were examined. Results showed that functional trait moments shifted significantly along the geographical gradients, and trait moments varied in different ways across different gradients. Plants generally showed coordinated trait shifts toward more conservative growth strategies (lower specific leaf area, leaf N and P concentration while higher leaf nitrogen/phosphorus and wood density) along increasing latitude and longitude. However, trends opposite to the latitudinal and longitudinal patterns appeared in trait mean values along elevation. The three sets of environmental variables (climate, soil and topography) explained 35.0–69.0%, 21.0–56.0%, 14.0–31.0%, and 16.0–30.0% of the variations in mean, variance, skewness, and kurtosis across the six functional traits, respectively. Patterns of shifts in functional trait moments along geographical gradients in the subtropical region were mainly determined by the joint effects of climatic and edaphic conditions. Climate regimes, especially climate variability, were the strongest driving force, followed by soil nutrients, while topography played the least role. Moreover, the relationship of variance, skewness and kurtosis with climate and their geographical patterns suggested that rare phenotypes at edges of trait space were selected in harsher environments. Our study suggested that environmental filtering (especially climate variability) was the dominant process of functional assembly for forest communities in the subtropical region along geographical gradients.

scholarly journals Laboratory study on the effects of nutrient enrichment on a phytoplankton population in Sawa Lake, Iraq

2008 ◽  
Vol 5 (2) ◽  
pp. 230-236 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Population Dynamics ◽  
Lake Water ◽  
Nutrient Enrichment ◽  
Cell Number ◽  
Shannon Index ◽  
Nitrogen And Phosphorus ◽  
Phytoplankton Population ◽  
Phytoplankton Cell ◽  
Nitrogen Phosphorus ◽  
Index Of Diversity

Nutrient enrichment of Sawa lake water was made using different nitrogen and phosphorus concentrations during autumn and spring at three stations. Different concentrations of nitrogen, phosphorus and N: P ratios were used to test variations in phytoplankton population dynamics. Nitrogen at a concentration of 25 µmole.l-1 and N: P ratio of 10:1 gave highest phytoplankton cell number at all stations and seasons. A total of 64 algal taxa dominated by Bacillariophyceae followed by Cyanophyceae and Chlorophyceae were identified. The values of Shannon index of diversity were more than one in the studied stations.

Mechanisms regulating spatial changes in grassland productivity following nutrient addition in northern China

2019 ◽  
Vol 41 (1) ◽  
pp. 83
Author(s):  
Na Zhao ◽  
Xinqing Shao ◽  
Chao Chen ◽  
Jiangwen Fan ◽  
Kun Wang
Keyword(s):  
Functional Traits ◽  
Plant Biomass ◽  
Northern China ◽  
Functional Trait ◽  
Community Response ◽  
Nutrient Addition ◽  
Leymus Chinensis ◽  
Ecosystem Functions ◽  
Natural Grasslands ◽  
Key Species

Plant biomass is the most fundamental component of ecosystems. The spatial stability of plant biomass is important, and the mechanisms regulating plant biomass spatial variability in variable environments are a central focus of ecology. However, they have rarely been explored. We conducted an experiment to test how diversity and functional traits affected variation in biomass and community response to nutrient availability in three plant communities: natural; forb, legume, and bunchgrass; and rhizomatous grass. We found that biomass stability rarely changed with increasing taxonomic species richness and functional group richness but declined with increasing Shannon–Weiner indices (the combination of richness and evenness) and functional trait diversity. However, differences in plant species composition generated different responses in both the amount and spatial variation of biomass following nutrient addition. Because rhizomatous grasses are weakly competitive in nutrient-poor conditions, interaction between resource-acquisitive (grass) and stress-tolerant (forb) species in the natural community conferred the greatest overall stability. The rapid nutrient acquisition ability of the rhizomatous grass Leymus chinensis was stimulated in nutrient-abundant conditions. The functional traits of this dominant species overrode the diversity interaction effects of the natural and forb, legume, and bunchgrass communities. This ultimately resulted in the rhizomatous grass community being the most stable. Community stability was strongly determined by a few key species, particularly rhizomatous grasses, rather than by the average response of all species, thereby supporting the mass ratio hypothesis. Our results indicated that rhizomatous grasses could provide vegetative productivity to reduce soil loss and prevent degradation of L. chinensis-dominant grassland. Thus, protecting specific species is critical for maintaining rangeland ecosystem functions. Moreover, the conservation importance of grasses, non-leguminous forbs, legumes, or even rare species could not be ignored. Maintaining stability mechanisms in natural grasslands is complex, and therefore, further studies need to focus on finding a unified mechanism that can regulate appreciable biomass variation under shifting environmental conditions.

scholarly journals Remotely Sensed Variables of Ecosystem Functioning Support Robust Predictions of Abundance Patterns for Rare Species

2019 ◽  
Vol 11 (18) ◽  
pp. 2086 ◽  
Author(s):  
Salvador Arenas-Castro ◽  
Adrián Regos ◽  
João F. Gonçalves ◽  
Domingo Alcaraz-Segura ◽  
João Honrado
Keyword(s):  
Species Distribution ◽  
Ecosystem Functioning ◽  
Environmental Changes ◽  
Predictive Accuracy ◽  
Species Abundance ◽  
Habitats Directive ◽  
The European Union ◽  
Distribution Models ◽  
Essential Information ◽  
Abundance Patterns

Global environmental changes are affecting both the distribution and abundance of species at an unprecedented rate. To assess these effects, species distribution models (SDMs) have been greatly developed over the last decades, while species abundance models (SAMs) have generally received less attention even though these models provide essential information for conservation management. With population abundance defined as an essential biodiversity variable (EBV), SAMs could offer spatially explicit predictions of species abundance across space and time. Satellite-derived ecosystem functioning attributes (EFAs) are known to inform on processes controlling species distribution, but they have not been tested as predictors of species abundance. In this study, we assessed the usefulness of SAMs calibrated with EFAs (as process-related variables) to predict local abundance patterns for a rare and threatened species (the narrow Iberian endemic ‘Gerês lily’ Iris boissieri; protected under the European Union Habitats Directive), and to project inter-annual fluctuations of predicted abundance. We compared the predictive accuracy of SAMs calibrated with climate (CLI), topography (DEM), land cover (LCC), EFAs, and combinations of these. Models fitted only with EFAs explained the greatest variance in species abundance, compared to models based only on CLI, DEM, or LCC variables. The combination of EFAs and topography slightly increased model performance. Predictions of the inter-annual dynamics of species abundance were related to inter-annual fluctuations in climate, which holds important implications for tracking global change effects on species abundance. This study underlines the potential of EFAs as robust predictors of biodiversity change through population size trends. The combination of EFA-based SAMs and SDMs would provide an essential toolkit for species monitoring programs.

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