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.

Vertical dynamics in community functioning of biofilm-dwelling ciliates during the colonisation process in coastal waters of the Yellow Sea

2019 ◽  
Vol 70 (11) ◽  
pp. 1611 ◽  
Author(s):  
Xiaoyun Bai ◽  
Congcong Guo ◽  
Mamun Abdullah Al ◽  
Alan Warren ◽  
Henglong Xu
Keyword(s):  
Functional Diversity ◽  
Functional Traits ◽  
Coastal Waters ◽  
Yellow Sea ◽  
Northern China ◽  
Diversity Indices ◽  
Functional Trait ◽  
The Yellow Sea ◽  
Biological Traits ◽  
Trait Distribution

Multifunctional trait analysis is increasingly recognised as an effective tool for assessing ecosystem function and environmental quality. Here, a baseline study was performed at four depths (i.e. 1, 2, 3.5 and 5m) in Yellow Sea coastal waters of northern China in order to determine the optimal depth for bioassessment using biological traits of biofilm-dwelling ciliates. Community-weighted means (CWM) from functional traits system were used to summarise the trait distribution and functional diversity of ciliates among the four depths during a 1-month colonisation period. Functional trait distribution revealed a clear temporal variation among the four depths. In total, 3 of 17 functional traits (i.e. feeding type, body size and flexibility) showed significant temporal patterns. Bootstrapped averaging and permutational multivariate analysis of variance (PERMANOVA) tests demonstrated that the colonisation pattern of biofilm-dwelling ciliates as expressed by CWM at 1 and 2m differed significantly from those at 3.5 and 5m. Functional diversity indices showed lower variability at 1 and 2m than at 3.5 and 5m. These results suggest that 1 and 2m are the preferred sampling depths for bioassessment of marine water quality using biological traits of biofilm-dwelling ciliates.

scholarly journals Plant trait response of tundra shrubs to permafrost thaw and nutrient addition

2020 ◽  
Vol 17 (20) ◽  
pp. 4981-4998
Author(s):  
Maitane Iturrate-Garcia ◽  
Monique M. P. D. Heijmans ◽  
J. Hans C. Cornelissen ◽  
Fritz H. Schweingruber ◽  
Pascal A. Niklaus ◽  
...  
Keyword(s):  
Functional Traits ◽  
Plant Traits ◽  
Nutrient Addition ◽  
Ecosystem Functions ◽  
Individual Plant ◽  
Growth Strategies ◽  
Mixed Effect ◽  
Permafrost Thaw ◽  
Plant Trait ◽  
Thaw Depth

Abstract. Plant traits reflect growth strategies and trade-offs in response to environmental conditions. Because of climate warming, plant traits might change, altering ecosystem functions and vegetation–climate interactions. Despite important feedbacks of plant trait changes in tundra ecosystems with regional climate, with a key role for shrubs, information on responses of shrub functional traits is limited. Here, we investigate the effects of experimentally increased permafrost thaw depth and (possibly thaw-associated) soil nutrient availability on plant functional traits and strategies of Arctic shrubs in northeastern Siberia. We hypothesize that shrubs will generally shift their strategy from efficient conservation to faster acquisition of resources through adaptation of leaf and stem traits in a coordinated whole-plant fashion. To test this hypothesis, we ran a 4 year permafrost thaw and nutrient fertilization experiment with a fully factorial block design and six treatment combinations – permafrost thaw (control, unheated cable, heated cable) × fertilization (no nutrient addition, nutrient addition). We measured 10 leaf and stem traits related to growth, defence and the resource economics spectrum in four shrub species (Betula nana, Salix pulchra, Ledum palustre and Vaccinium vitis-idaea), which were sampled in the experimental plots. The plant trait data were statistically analysed using linear mixed-effect models and principal component analysis (PCA). The response to increased permafrost thaw was not significant for most shrub traits. However, all shrubs responded to the fertilization treatment, despite decreased thaw depth and soil temperature in fertilized plots. Shrubs tended to grow taller but did not increase their stem density or bark thickness. We found a similar coordinated trait response for all four species at leaf and plant level; i.e. they shifted from a conservative towards a more acquisitive resource economy strategy upon fertilization. In accordance, results point towards a lower investment into defence mechanisms, and hence increased shrub vulnerability to herbivory and climate extremes. Compared to biomass and height only, detailed data involving individual plant organ traits such as leaf area and nutrient contents or stem water content can contribute to a better mechanistic understanding of feedbacks between shrub growth strategies, permafrost thaw and carbon and energy fluxes. In combination with observational data, these experimental tundra trait data allow for a more realistic representation of tundra shrubs in dynamic vegetation models and robust prediction of ecosystem functions and related climate–vegetation–permafrost feedbacks.

scholarly journals Plant trait response of tundra shrubs to permafrost thaw and nutrient addition

2020 ◽  
Author(s):  
Maitane Iturrate-Garcia ◽  
Monique M. P. D. Heijmans ◽  
J. Hans C. Cornelissen ◽  
Fritz H. Schweingruber ◽  
Pascal A. Niklaus ◽  
...  
Keyword(s):  
Functional Traits ◽  
Plant Traits ◽  
Nutrient Addition ◽  
Ecosystem Functions ◽  
Individual Plant ◽  
Growth Strategies ◽  
Mixed Effect ◽  
Permafrost Thaw ◽  
Plant Trait ◽  
Thaw Depth

Abstract. Plant traits reflect growth strategies and trade-offs in response to environmental conditions. Because of climate warming, plant traits might adapt, altering ecosystem functions and vegetation–climate interactions. Despite important feedbacks of plant trait changes in tundra ecosystems with regional climate, with a key role for shrubs, information on responses of shrub functional traits is limited. Here, we investigate the effects of experimentally increased permafrost thaw depth and (possibly thaw-associated) soil nutrient availability on plant functional traits and strategies of arctic shrubs in northeastern Siberia. We hypothesize that shrubs will generally shift their strategy from efficient conservation to faster acquisition of resources through adaptation of leaf and stem traits in a coordinated whole-plant fashion. Thereto we ran a 4-year permafrost thaw and nutrient fertilization experiment with a fully factorial block design and six treatment combinations – permafrost thaw (control, unheated cable, heated cable) x fertilization (no-nutrient addition, nutrient addition). We measured ten leaf and stem traits related to growth, defence and the resource economics spectrum in four shrub species, which were sampled in the experimental plots. The plant trait data were statistically analysed using linear mixed-effect models and principal component analysis (PCA). The response to increased permafrost thaw was not significant for most shrub traits. However, all shrubs responded to the fertilization treatment, despite decreased thaw depth and soil temperature in fertilized plots. Shrubs tended to grow taller, but did not increase their stem density or bark thickness. We found a similar coordinated trait response for all four species at leaf and plant level, i.e. they shifted from a conservative towards a more acquisitive resource economy strategy upon fertilization. In accordance, results point towards a lower investment into defence mechanisms, and hence increased shrub vulnerability to herbivory and climate extremes. Compared to biomass and height only, detailed data involving individual plant organ traits such as leaf area and nutrient contents or stem water content can contribute to a better mechanistic understanding of feedbacks between shrub growth strategies, permafrost thaw and carbon and energy fluxes. In combination with observational data, these experimental tundra trait data allow for a more realistic representation of tundra shrubs in dynamic vegetation models and robust prediction of ecosystem functions and related climate-vegetation-permafrost feedbacks.

scholarly journals The Effect of Fertilizers on Biomass and Biodiversity on a Semi-Arid Grassland of Northern China

2019 ◽  
Vol 11 (10) ◽  
pp. 2854 ◽  
Author(s):  
Zongyong Tong ◽  
Guoling Quan ◽  
Liqiang Wan ◽  
Feng He ◽  
Xianglin Li
Keyword(s):  
Aboveground Biomass ◽  
Plant Biomass ◽  
Diversity Index ◽  
Northern China ◽  
Organic Fertilizers ◽  
Leymus Chinensis ◽  
Mineral Fertilizers ◽  
Species Diversity Index ◽  
Natural Grassland ◽  
Semi Arid

Semi-arid grassland in northern China faces degradation and desertification problems, with fertilizer application appearing to be a potential solution by improving soil fertility and plant fields or biodiversity. In this study, mineral and organic fertilizers were used in a semi-arid natural grassland in Hebei Province for three years. The plant characteristics, biomass and species diversity index were assessed and analyzed. In the years 2016 and 2017, mineral fertilizers (RC) significantly increased the total aboveground biomass and the aboveground biomass, natural height, density and coverage of Leymus chinensis compared with organic fertilizers (RO), especially at a moderate application rate (RC2). Leymus chinensis was first divided into its own group and then separated into four groups via cluster tree analysis. The importance values of Leymus chinensis showed continuous increases in mineral fertilizer treatments, but not for organic fertilizers. Margalef’s species richness indexes increased significantly (to 2.09) in the organic treatment (RO1) when compared with RC2. Thus, it was concluded that mineral fertilizers could enhance the position of Leymus chinensis in the natural grassland, while organic fertilizers could promote species biodiversity. This study also provides recommendations regarding the use of fertilizers for the purposes of increasing plant biomass and biodiversity in semi-arid grasslands of northern China.

scholarly journals The Potential of Mapping Grassland Plant Diversity with the Links among Spectral Diversity, Functional Trait Diversity, and Species Diversity

2021 ◽  
Vol 13 (15) ◽  
pp. 3034
Author(s):  
Yujin Zhao ◽  
Yihan Sun ◽  
Wenhe Chen ◽  
Yanping Zhao ◽  
Xiaoliang Liu ◽  
...  
Keyword(s):  
Species Diversity ◽  
Plant Species ◽  
Functional Traits ◽  
Plant Diversity ◽  
Functional Trait ◽  
Remotely Sensed ◽  
Ecosystem Functions ◽  
Grass Species ◽  
Trait Diversity ◽  
Functional Trait Diversity

Mapping biodiversity is essential for assessing conservation and ecosystem services in global terrestrial ecosystems. Compared with remotely sensed mapping of forest biodiversity, that of grassland plant diversity has been less studied, because of the small size of individual grass species and the inherent difficulty in identifying these species. The technological advances in unmanned aerial vehicle (UAV)-based or proximal imaging spectroscopy with high spatial resolution provide new approaches for mapping and assessing grassland plant diversity based on spectral diversity and functional trait diversity. However, relatively few studies have explored the relationships among spectral diversity, remote-sensing-estimated functional trait diversity, and species diversity in grassland ecosystems. In this study, we examined the links among spectral diversity, functional trait diversity, and species diversity in a semi-arid grassland monoculture experimental site. The results showed that (1) different grassland plant species harbored different functional traits or trait combinations (functional trait diversity), leading to different spectral patterns (spectral diversity). (2) The spectral diversity of grassland plant species increased gradually from the visible (VIR, 400–700 nm) to the near-infrared (NIR, 700–1100 nm) region, and to the short-wave infrared (SWIR, 1100–2400 nm) region. (3) As the species richness increased, the functional traits and spectral diversity increased in a nonlinear manner, finally tending to saturate. (4) Grassland plant species diversity could be accurately predicted using hyperspectral data (R2 = 0.73, p < 0.001) and remotely sensed functional traits (R2 = 0.66, p < 0.001) using cluster algorithms. This will enhance our understanding of the effect of biodiversity on ecosystem functions and support regional grassland biodiversity conservation.

Dominance determines fish community biomass in a temperate seagrass ecosystem

2019 ◽  
Author(s):  
Aaron Matthius Eger ◽  
Rebecca J. Best ◽  
Julia Kathleen Baum
Keyword(s):  
Species Richness ◽  
Ecosystem Function ◽  
Fish Community ◽  
Prey Capture ◽  
Fish Communities ◽  
Functional Trait ◽  
Ecosystem Functions ◽  
Community Biomass ◽  
Ecosystem Valuation ◽  
Species Abundances

Biodiversity and ecosystem function are often correlated, but there are multiple hypotheses about the mechanisms underlying this relationship. Ecosystem functions such as primary or secondary production may be maximized by species richness, evenness in species abundances, or the presence or dominance of species with certain traits. Here, we combined surveys of natural fish communities (conducted in July and August, 2016) with morphological trait data to examine relationships between diversity and ecosystem function (quantified as fish community biomass) across 14 subtidal eelgrass meadows in the Northeast Pacific (54° N 130° W). We employed both taxonomic and functional trait measures of diversity to investigate if ecosystem function is driven by species diversity (complementarity hypothesis) or by the presence or dominance of species with particular trait values (selection or dominance hypotheses). After controlling for environmental variation, we found that fish community biomass is maximized when taxonomic richness and functional evenness is low, and in communities dominated by species with particular trait values – those associated with benthic habitats and prey capture. While previous work on fish communities has found that species richness is positively correlated with ecosystem function, our results instead highlight the capacity for regionally prevalent and locally dominant species to drive ecosystem function in moderately diverse communities. We discuss these alternate links between community composition and ecosystem function and consider their divergent implications for ecosystem valuation and conservation prioritization.

scholarly journals A research framework for projecting ecosystem change in highly diverse tropical mountain ecosystems

Oecologia ◽  
2021 ◽  
Author(s):  
Jörg Bendix ◽  
Nicolay Aguire ◽  
Erwin Beck ◽  
Achim Bräuning ◽  
Roland Brandl ◽  
...  
Keyword(s):  
Land Use ◽  
Functional Traits ◽  
Biomass Production ◽  
Environmental Changes ◽  
Ecosystem Functions ◽  
Ecosystem Change ◽  
Mountain Ecosystems ◽  
Abiotic Conditions ◽  
Research Framework ◽  
Tropical Mountain

AbstractTropical mountain ecosystems are threatened by climate and land-use changes. Their diversity and complexity make projections how they respond to environmental changes challenging. A suitable way are trait-based approaches, by distinguishing between response traits that determine the resistance of species to environmental changes and effect traits that are relevant for species' interactions, biotic processes, and ecosystem functions. The combination of those approaches with land surface models (LSM) linking the functional community composition to ecosystem functions provides new ways to project the response of ecosystems to environmental changes. With the interdisciplinary project RESPECT, we propose a research framework that uses a trait-based response-effect-framework (REF) to quantify relationships between abiotic conditions, the diversity of functional traits in communities, and associated biotic processes, informing a biodiversity-LSM. We apply the framework to a megadiverse tropical mountain forest. We use a plot design along an elevation and a land-use gradient to collect data on abiotic drivers, functional traits, and biotic processes. We integrate these data to build the biodiversity-LSM and illustrate how to test the model. REF results show that aboveground biomass production is not directly related to changing climatic conditions, but indirectly through associated changes in functional traits. Herbivory is directly related to changing abiotic conditions. The biodiversity-LSM informed by local functional trait and soil data improved the simulation of biomass production substantially. We conclude that local data, also derived from previous projects (platform Ecuador), are key elements of the research framework. We specify essential datasets to apply this framework to other mountain ecosystems.

Response of plant functional traits of Leymus chinensis to extreme drought in Inner Mongolia grasslands

Plant Ecology ◽  
2018 ◽  
Vol 220 (2) ◽  
pp. 141-149 ◽  
Author(s):  
Xiyuan Yue ◽  
Xiaoan Zuo ◽  
Qiang Yu ◽  
Chong Xu ◽  
Peng Lv ◽  
...  
Keyword(s):  
Functional Traits ◽  
Inner Mongolia ◽  
Plant Functional Traits ◽  
Extreme Drought ◽  
Leymus Chinensis

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 Canopy Leaf Traits, Basal Area, and Age Predict Functional Patterns of Regenerating Communities in Secondary Subtropical Forests

2021 ◽  
Vol 4 ◽  
Author(s):  
Sandra Cristina Müller ◽  
Rodrigo Scarton Bergamin ◽  
Kauane Maiara Bordin ◽  
Joice Klipel ◽  
Milena Fermina Rosenfield
Keyword(s):  
Functional Diversity ◽  
Functional Traits ◽  
Natural Regeneration ◽  
Basal Area ◽  
Leaf Traits ◽  
Leaf Nitrogen ◽  
Ecosystem Functions ◽  
Secondary Forests ◽  
Functional Composition ◽  
Forest Age

Secondary forests originate from natural regeneration after fallow (succession) or restoration. Species assembly in these communities, which can affect ecosystem functions and successional trajectories, is very unpredictable. Trait-based trajectories can shed light on the recovery of ecosystem functions and enable predictions of how the regenerating communities will change with forest age. Regeneration communities are affected by initial conditions and also by canopy structure and functional traits that alter dispersers' attractiveness and coexistence mechanisms. Here we evaluated how community functional traits change over time and tested if functional diversity and composition of the established canopy, as well as the structure of the canopy and forest age, influence the functional structure of regenerating tree communities when compared to their reference forests. For this, we calculated dissimilarity in trait composition (community-weighted means) and in functional diversity of regenerating communities of each succession/restoration stand, using the tree stratum of nearby mature forests as baseline values. Functional trait information comprises leaf, wood density, and reproductive traits from tree species. Our community data contain information from natural successional forests and restoration sites, in the South-Brazilian Atlantic Forest. Predictor variables of functional dissimilarities were forest age, canopy structural variables, canopy functional composition, and functional diversity. Results showed leaf traits (leaf dry matter content, leaf nitrogen content, leaf nitrogen-phosphorus ratio) and seed mass varying with forest age. Canopy functional composition based on leaf traits and total basal area significantly predicted multiple trait functional dissimilarity between the regeneration component of secondary forests and their reference community values. Dissimilarity increased when the canopy was composed of species with more acquisitive traits. Difference in functional diversity was only influenced by forest age. Mid-stage secondary forests showed lower functional diversity than early-stage forests. Our results indicated the importance of canopy traits on the natural regeneration of secondary subtropical forests. If functional similarity with reference forests is a desired objective in order to recover ecosystem functions through natural regeneration, leaf functional traits of canopy trees that establish or are planted in degraded areas must be considered in the successional processes.

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