scholarly journals Effect of Grazing Types on Community-Weighted Mean Functional Traits and Ecosystem Functions on Inner Mongolian Steppe, China

2020 ◽  
Vol 12 (17) ◽  
pp. 7169
Author(s):  
Wen Wang ◽  
Huamin Liu ◽  
Jinghui Zhang ◽  
Zhiyong Li ◽  
Lixin Wang ◽  
...  
Keyword(s):  
Functional Traits ◽  
Nutrient Content ◽  
Co2 Exchange ◽  
Ecosystem Functions ◽  
Weighted Mean ◽  
Nitrogen And Phosphorus ◽  
Inner Mongolia Grassland ◽  
Grassland Ecosystems ◽  
Community Weighted Mean ◽  
Set Up

The relationships between community-weighted mean (CWM) functional traits and ecosystem functions have been extensively studied. However, how CWM traits and ecosystem functions respond to grazing types and whether the relationships between CWM traits and ecosystem functions mediate the response of ecosystem functions to grazing types remains controversial. In the present study, we set up a seven-year grazing experiment with four grazing types: no grazing (NG), cattle grazing (CG), sheep grazing (SG), and mixed grazing by sheep and cattle (MG) on Inner Mongolia grassland. Nine functional traits of dominant species and five ecosystem functions under different grazing types were determined, and the relationships between CWM traits and ecosystem functions were analyzed. The results showed that the CWM height decreased after grazing, while the CWM nitrogen and phosphorus contents increased after CG. SG caused a greater decrease in aboveground biomass (AGB) and a greater increase in the net ecosystem CO2 exchange (NEE) of grassland ecosystems than did CG. This result may be partially because the CWM nutrient content and NEE were more negatively related after CG; and the increase in the CWM nitrogen and phosphorus contents suppressed NEE after CG. Therefore, to protect the sustainability of grassland ecosystem functions, SG should be reduced. Additionally, our work emphasizes that the relationships between plant functional traits and ecosystem functions may mediate the response of ecosystem functions to grazing types.

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

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.

scholarly journals Disentangling the Contributions of Plant Taxonomic and Functional Diversities in Shaping Aboveground Biomass of a Restored Forest Landscape in Southern China

Plants ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 612 ◽  
Author(s):  
Md. Abu Hanif ◽  
Qingshui Yu ◽  
Xingquan Rao ◽  
Weijun Shen
Keyword(s):  
Species Richness ◽  
Resource Use ◽  
Aboveground Biomass ◽  
Southern China ◽  
Nutrient Content ◽  
Taxonomic Diversity ◽  
Ecosystem Functions ◽  
Functional Versus ◽  
Positive Regulators ◽  
Community Weighted Mean

Restoration is essential for supporting key ecosystem functions such as aboveground biomass production. However, the relative importance of functional versus taxonomic diversity in predicting aboveground biomass during restoration is poorly studied. Here, we used a trait-based approach to test for the importance of multiple plant diversity attributes in regulating aboveground biomass in a 30-years-old restored subtropical forest in southern China. We show that both taxonomic and functional diversities are significant and positive regulators of aboveground biomass; however, functional diversity (FD) was more important than taxonomic diversity (species richness) in controlling aboveground biomass. FD had the strongest direct effect on aboveground biomass compared with species richness, soil nutrients, and community weighted mean (CWM) traits. Our results further indicate that leaf and root morphological traits and traits related to the nutrient content in plant tissues represent the existence of a leaf and root economic spectrum, and the acquisitive resource use strategy influenced aboveground biomass. Our results suggest that both taxonomic and FD play a role in shaping aboveground biomass, but FD is more important in supporting aboveground biomass in this type of environments. These results imply that enhancing FD is important to restoring and managing degraded forest landscapes.

scholarly journals Functional traits predict species responses to environmental variation in a California grassland annual plant community

2020 ◽  
Author(s):  
Gaurav S. Kandlikar ◽  
Andew R. Kleinhesselink ◽  
Nathan J.B. Kraft
Keyword(s):  
Functional Traits ◽  
Environmental Variation ◽  
Plant Functional Traits ◽  
Community Level ◽  
List Type ◽  
Annual Plant ◽  
Weighted Mean ◽  
California Grassland ◽  
Community Weighted Mean ◽  
Species Responses

AbstractTurnover in species composition and community-wide functional traits across environmental gradients is a ubiquitous pattern in ecology, and is generally assumed to reflect shifts in trait optima across these gradients. However, the demographic processes that give rise to these trait turnover patterns at the community level remain unclear.We asked whether shifts in the community-weighted means of three key functional traits across an environmental gradient in a southern California grassland reflect variation in the trait-performance relationship across the landscape.We planted seeds of 17 annual plant species in cleared patches with no competitors, and quantified the lifetime seed production of 1360 individuals. We then asked whether models that included trait-environment interactions help explain interspecific variation in demographic responses to the environment. This allowed us to evaluate whether observed shifts in community-weighted mean traits matched the direction of any trait-environment interactions detected in the plant performance experiment.Our results indicate that commonly-measured plant functional traits help explain variation in species responses to the environment – for example, high-SLA species had a demographic advantage in soils with high soil Ca:Mg levels, while low-SLA species had an advantage in low Ca:Mg soils. We also found that shifts in community-weighted mean traits often reflect the direction of these trait-environment interactions, though not all trait-environment relationships at the community level reflect interactive effects of traits and environment on species performance.Our results support the value of plant functional traits for predicting species responses to environmental variation, and highlight a need for more detailed evaluation of how trait-performance relationships change across environments to improve such predictions.

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.

scholarly journals Leaf Nutrient Relations of Cycads in a Common Garden

2021 ◽  
Vol 14 ◽  
pp. 194008292110365
Author(s):  
Thomas E. Marler ◽  
Anders J. Lindström
Keyword(s):  
Common Garden ◽  
Nutrient Content ◽  
Leaf Traits ◽  
Botanical Garden ◽  
Active Management ◽  
Nitrogen And Phosphorus ◽  
Representative Species ◽  
Nutrient Relations ◽  
Homogeneous Environment ◽  
Dry Combustion

Background and Aims Research required to clarify leaf nutrient relations of cycad species has been inadequate. Common garden studies are useful for determining the influence of genetics on leaf traits because of the homogeneous environment among experimental units. To date, there have been no common garden studies which included all ten genera of cycads. The full phylogenetic breadth has, therefore, not been included in this important area of study. Methods We examined macronutrient and micronutrient content of leaves from one representative species from each of the ten cycad genera at Nong Nooch Tropical Botanical Garden in Thailand. Nitrogen content was determined by dry combustion, and the remaining nutrients were quantified by spectrometry. Results The least variable elements were nitrogen and phosphorus, and the most variable elements were boron and sodium. Nutrient content based on leaflet area was more variable than based on leaflet mass, reflecting species differences in specific leaf area. There were no universal macronutrient or micronutrient signals indicating clear phylogenetic distinctions. Implications for Conservation: Active management of threatened cycad taxa requires research to develop the knowledge to enable evidence-based decisions. This common garden study inclusive of all 10 cycad genera creates a foundation to determine leaf nutrient sufficiency ranges to inform management decisions.

scholarly journals Phytoplankton community structure in Menjer Lake, Central Java

2021 ◽  
Vol 869 (1) ◽  
pp. 012037
Author(s):  
F Sulawesty ◽  
G P Yoga ◽  
L Subehi ◽  
R Rosidah
Keyword(s):  
Community Structure ◽  
Phytoplankton Community ◽  
Diversity Index ◽  
Nutrient Content ◽  
Cell Counting ◽  
Phytoplankton Community Structure ◽  
Nitrogen And Phosphorus ◽  
Central Java ◽  
Phytoplankton Communities ◽  
Ecological Pressure

Abstract The occurrence of land changes around Lake Menjer, Central Java Province will affect the condition of water quality subsequently will affect biota, including phytoplankton. The purposes of study was to analyze the composition and abundance of phytoplankton in Menjer Lake regarding to nutrient content i.e. nitrogen and phosphorus. Observations on the phytoplankton community were conducted in July and October 2019 at six locations in Menjer Lake. Water samples were taken at the water surface as much as 10 L filtered using plankton net. Identification was carried out under the inverted microscope Diaphot 300. The abundance was calculated using the Sedgwick Rafter cell counting (SRCC) method. Analysis of the phytoplankton community structure was derived by calculating the Diversity Index, Evenness Index, and Simpson Dominance Index. The nutrient content in Menjer Lake influences the structure of phytoplankton communities quantitatively and qualitatively. Observation showed that the diversity of phytoplankton was low and there was one species dominanted, the result explained that the phytoplankton community in Menjer Lake is unstable and there is ecological pressure on the community. It can be concluded that the improvement of environmental conditions around Menjer Lake is the basis for the sustainable management of Menjer Lake.

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.

scholarly journals Influence of Height of Cane and Leaf Stage at Time of Sampling on Leaf-Nutrient Content of Sugarcane

1969 ◽  
Vol 44 (1) ◽  
pp. 11-15
Author(s):  
G. Samuels ◽  
S. Alers-Alers ◽  
P. Landrau, Jr.
Keyword(s):  
Nutrient Content ◽  
Leaf Nitrogen ◽  
Sampling Time ◽  
Nitrogen And Phosphorus ◽  
Leaf Sample ◽  
Leaf Stage ◽  
Fertilizer Experiment ◽  
Significant Difference ◽  
Leaf Sampling ◽  
Number Of Leaves

Leaf samples of sugarcane were taken from a fertilizer experiment at Río Piedras with varieties B. 41227 and M. 336 to determine whether the height of cane or the number of leaves present at leaf-sampling time influenced the nutrient content of the leaf sample. It was found that: 1. There was no significant difference in leaf nitrogen or potassium from cane tillers aged 3 months with heights of 12, 24, and 36 inches. 2. Variations in cane height at time of sampling did influence leaf-phosphorus values; there were increases in cane height. 3. The number of leaves present at time of sampling (7-13 weeks) did not influence leaf-nutrient values in general, except for nitrogen and phosphorus at 9 weeks of age. Here the trends of this influence with the two varieties studied were contrary.

scholarly journals A model for variable phytoplankton stoichiometry based on cell protein regulation

2013 ◽  
Vol 10 (2) ◽  
pp. 3241-3279
Author(s):  
J. A. Bonachela ◽  
S. D. Allison ◽  
A. C. Martiny ◽  
S. A. Levin
Keyword(s):  
Physiological State ◽  
Single Point ◽  
Nutrient Content ◽  
Growth Conditions ◽  
Marine Phytoplankton ◽  
Cell Protein ◽  
Nitrogen And Phosphorus ◽  
Elemental Ratios ◽  
Regulatory Processes ◽  
Complex Interactions

Abstract. The elemental ratios of marine phytoplankton emerge from complex interactions between the biotic and abiotic components of the ocean, and reflect the plastic response of individuals to changes in their environment. The stoichiometry of phytoplankton is, thus, dynamic and dependent on the physiological state of the cell. We present a theoretical model for the dynamics of the carbon, nitrogen and phosphorus contents of a phytoplankton population. By representing the regulatory processes controlling nutrient uptake, and focusing on the relation between nutrient content and protein synthesis, our model qualitatively replicates existing experimental observations for nutrient content and ratios. The population described by our model takes up nutrients in proportions that match the input ratios for a broad range of growth conditions. In addition, there are two zones of single-nutrient limitation separated by a wide zone of co-limitation. Within the co-limitation zone, a single point can be identified where nutrients are supplied in an optimal ratio. The existence of a wide co-limitation zone affects the standard picture for species competing for nitrogen and phosphorus, which shows here a much richer pattern. However, additional comprehensive laboratory experiments are needed to test our predictions. Our model contributes to the understanding of the global cycles of oceanic nitrogen and phosphorus, as well as the elemental ratios of these nutrients in phytoplankton populations.

Sign in / Sign up

Export Citation Format

Share Document