scholarly journals Intraspecific trait changes have large impacts on community functional composition but do not affect ecosystem function

2021 ◽  
Author(s):  
Noémie A. Pichon ◽  
Seraina L. Cappelli ◽  
Eric Allan
Keyword(s):  
Global Change ◽  
Biomass Production ◽  
Aboveground Biomass ◽  
Belowground Biomass ◽  
Nitrogen Enrichment ◽  
Functional Composition ◽  
Relative Importance ◽  
Pathogen Removal ◽  
Weighted Mean ◽  
Community Weighted Mean

AbstractPlant functional traits can provide a more mechanistic understanding of community responses to global change and effects on ecosystem functions. In particular, nitrogen enrichment shifts trait composition by promoting dominance of fast growing, acquisitive plants (with high specific leaf area [SLA] and low leaf dry matter content [LDMC]), and such fast species have higher aboveground biomass production. Changes in mean trait values can be due to a shift in species identity, a shift in species relative abundance and/or a shift in intraspecific trait values. However, we do not know the relative importance of these three shifts in determining responses to global change and effects on function.We quantified the relative importance of composition, abundance and intraspecific shifts in driving variation in SLA and LDMC. We collected leaf samples in a large grassland experiment, which factorially manipulates functional composition (slow vs. fast species), plant species richness, nitrogen enrichment and foliar fungal pathogen removal. We fitted structural equation models to test the relative importance of abundance shifts, intraspecific shifts and sown trait composition in contributing to overall variation in community weighted mean traits and aboveground and belowground biomass production.We found that intraspecific shifts were as important as abundance shifts in determining community weighted mean traits, and even had large effects relative to a wide initial gradient in trait composition. Intraspecific trait shifts resulted in convergence towards intermediate SLA, in diverse communities, although convergence was reduced by nitrogen addition and enhanced by pathogen removal. In contrast, large intraspecific shifts in LDMC were not influenced by the treatments. Belowground biomass was reduced by SLA and increased by LDMC, while aboveground biomass increased in communities dominated by high SLA species. However, despite large intraspecific trait shifts, intraspecific variation in these traits had no effect on above or belowground biomass production.Our results add to a growing body of literature showing large intraspecific trait variation and emphasise the importance of using field sampled data to determine community composition. However, they also show that intraspecific variation does not affect ecosystem functioning and therefore trait response-effect relationships may differ between vs. within species.

Summer warming effects on biomass production and clonal growth of Leymus chinensis

2010 ◽  
Vol 61 (8) ◽  
pp. 670 ◽  
Author(s):  
Jun-Feng Wang ◽  
Song Gao ◽  
Ji-Xiang Lin ◽  
Yong-Guang Mu ◽  
Chun-Sheng Mu
Keyword(s):  
Biomass Production ◽  
Aboveground Biomass ◽  
Clonal Growth ◽  
Belowground Biomass ◽  
Growth Strategy ◽  
Perennial Grasses ◽  
Leymus Chinensis ◽  
Shoot Number ◽  
Summer Warming ◽  
Rhizome Buds

Understanding how the biomass production and clone growth of perennial grasses respond to summer warming is crucial for understanding how grassland productivity responds to global warming. Here, we experimentally investigated the effects of summer warming on the biomass production and clonal growth of potted Leymus chinensis in a phytotron. Summer warming significantly decreased the biomass of both parent and daughter shoots, slightly increased the belowground biomass, and lead to a significant increase in root : shoot ratio. Warming significantly increased the total belowground bud number and decreased the daughter shoot number. Importantly, the proportions of each type of bud changed; vertical apical rhizome buds decreased, while horizontal rhizome buds increased in number. The change in proportions of each type of bud is closely related to the decrease in daughter shoot number, rhizome number and length, as well as the decrease in aboveground biomass and increase in belowground biomass. These results indicate that, as a rhizomatous, perennial grass, L. chinensis adopts a selective growth strategy that reduces the energy allocated to aboveground growth and emphasises the development of belowground organs. The implication is that continued summer warming, will further reduce the aboveground biomass production of temperate grasslands dominated by rhizomatous, perennial grasses. Inevitably, species that depend on these grasses for forage will suffer should global climate warming continue.

scholarly journals Contrasting adaptation and optimization of stomatal traits across communities at continental-scale

2021 ◽  
Author(s):  
Congcong Liu ◽  
Lawren Sack ◽  
Ying Li ◽  
Nianpeng He
Keyword(s):  
Niche Differentiation ◽  
Relative Importance ◽  
Ecosystem Productivity ◽  
Weighted Mean ◽  
Continental Scale ◽  
Community Weighted Mean ◽  
Use Efficiency ◽  
Stomatal Traits ◽  
Mean Variance ◽  
Maximum Stomatal Conductance

The maximum stomatal conductance (g), a major anatomical constraint on plant productivity, is a function of the stomatal area fraction (f) and stomatal space-use efficiency (e). However, f and g have been considered as equivalents, with e rarely considered, and their adaptation to the environment and their regulation of ecosystem productivity are unclear. Here, we analyzed the community-weighted mean, variance, skewness, and kurtosis of stomatal traits from tropical to cold-temperature forests. The variance of g and f was higher for arid sites, indicating greater functional niche differentiation, whereas that for e was lower, indicating convergence in efficiency. Besides, when other stomatal trait distributions remained unchanged, increasing kurtosis but decreasing skewness of g would improve ecosystem productivity, and f showed the opposite patterns. These findings highlight how the relative importance and equivalence of inter-related traits can differ at community scale.

Anthropogenic nitrogen enrichment increased the efficiency of belowground biomass production in a boreal forest

2021 ◽  
Vol 155 ◽  
pp. 108154
Author(s):  
Benjamin Forsmark ◽  
Annika Nordin ◽  
Nicholas P. Rosenstock ◽  
Håkan Wallander ◽  
Michael J. Gundale
Keyword(s):  
Boreal Forest ◽  
Biomass Production ◽  
Belowground Biomass ◽  
Nitrogen Enrichment ◽  
Anthropogenic Nitrogen

scholarly journals Effect of Density on Mediterranean Pine Seedlings Using the Nelder Wheel Design: Analysis of Biomass Production

2021 ◽  
Author(s):  
Irene Ruano ◽  
Celia Herrero ◽  
Felipe Bravo
Keyword(s):  
Biomass Production ◽  
Aboveground Biomass ◽  
Pinus Pinaster ◽  
Root Biomass ◽  
Pinus Halepensis ◽  
Belowground Biomass ◽  
Total Biomass ◽  
Production And Distribution ◽  
Mediterranean Pine ◽  
Positive Effect

Abstract BackgroundForest resilience should be improved to promote species adaptation and ensure the future of forests. Carbon stock is considered an indicator of resilience, so it is necessary to determine forest carbon stocks and how to improve them through forest management. The main objective of this study was to analyse biomass production and distribution among the components of four-year-old Pinus pinaster and Pinus halepensis trees. Young trees from a Nelder wheel experimental site were harvested and analysed. The effect of density could be included in the biomass analysis thanks to the Nelder wheel design. We tested densities from 1000 to 80000 seedlings/ha and analysed biomass by fitting different equations: (i) linear regressions to analyse biomass production; (ii) Dirichlet regressions to estimate the biomass proportions of each component and (iii) allometric equations to predict the biomass content of each component.ResultsResults from this innovative approach showed that density was a significant factor for Pinus halepensis. We observed a general increase of total biomass at lower densities and this positive effect increased root biomass proportion at the expense of aboveground biomass. Also, a new set of equations was developed for estimating above- and below-ground biomass in young Pinus pinaster and Pinus halepensis trees.Conclusionswe note the importance of belowground biomass and its value in total biomass production (approximately 20% of total biomass for both species). The effect of density on biomass production was only significant for Pinus halepensis, but the effect of density would have been different if root biomass had not been considered in the present study. Lower densities increased root biomass proportion at the expense of aboveground biomass. Currently, this positive effect is especially important in promoting management to improve tree resilience.

Effects of grazing intensity on organic carbon stock characteristics in Stipa breviflora desert steppe vegetation soil systems

2017 ◽  
Vol 39 (2) ◽  
pp. 169 ◽  
Author(s):  
Heyun Wang ◽  
Zhi Dong ◽  
Jianying Guo ◽  
Hongli Li ◽  
Jinrong Li ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Aboveground Biomass ◽  
Carbon Stock ◽  
Belowground Biomass ◽  
Total Carbon ◽  
Desert Steppe ◽  
Light Fraction Organic Carbon ◽  
Grazing Intensities ◽  
Organic Carbon Stock

Grassland ecosystems, an important component of the terrestrial environment, play an essential role in the global carbon cycle and balance. We considered four different grazing intensities on a Stipa breviflora desert steppe: heavy grazing (HG), moderate grazing (MG), light grazing (LG), and an area fenced to exclude livestock grazing as the Control (CK). The analyses of the aboveground biomass, litter, belowground biomass, soil organic carbon and soil light fraction organic carbon were utilised to study the organic carbon stock characteristics in the S. breviflora desert steppe under different grazing intensities. This is important to reveal the mechanisms of grazing impact on carbon processes in the desert steppe, and can provide a theoretical basis for conservation and utilisation of grassland resources. Results showed that the carbon stock was 11.98–44.51 g m–2 in aboveground biomass, 10.43–36.12 g m–2 in plant litters, and 502.30–804.31 g m–2 in belowground biomass (0–40 cm). It was significantly higher in CK than in MG and HG. The carbon stock at 0–40-cm soil depth was 7817.43–9694.16 g m–2, and it was significantly higher in LG than in CK and HG. The total carbon stock in the vegetation-soil system was 8342.14–10494.80 g m–2 under different grazing intensities, with the largest value in LG, followed by MG, CK, and HG. About 90.54–93.71% of the total carbon in grassland ecosystem was reserved in soil. The LG and MG intensities were beneficial to the accumulation of soil organic carbon stock. The soil light fraction organic carbon stock was 484.20–654.62 g m–2 and was the highest under LG intensity. The LG and MG intensities were beneficial for soil nutrient accumulation in the desert steppe.

scholarly journals Context-dependency in biodiversity-multifunctionality relationships is driven by nitrogen availability and plant functional composition

2020 ◽  
Author(s):  
Noémie A. Pichon ◽  
Seraina L. Cappelli ◽  
Santiago Soliveres ◽  
Tosca Mannall ◽  
Thu Zar Nwe ◽  
...  
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Functional Diversity ◽  
Experimental Studies ◽  
Plant Species Richness ◽  
Trophic Levels ◽  
Context Dependency ◽  
Composition Gradient ◽  
Nitrogen Enrichment ◽  
Functional Composition

SummaryThe ability of an ecosystem to deliver multiple functions at high levels (multifunctionality) typically increases with biodiversity but there is substantial variation in the strength and direction of biodiversity effects, suggesting context-dependency. However, the drivers of this context dependency have not been identified and understood in comparative meta-analyses or experimental studies. To determine how different factors modulate the effect of diversity on multifunctionality, we conducted a large grassland experiment with 216 communities, crossing a manipulation of plant species richness (1-20 species) with manipulations of resource availability (nitrogen enrichment), plant functional composition (gradient in mean specific leaf area [SLA] to manipulate abundances of fast vs. slow species), plant functional diversity (variance in SLA) and enemy abundance (fungal pathogen removal). We measured ten functions, above and belowground, related to productivity, nutrient cycling and energy transfer between trophic levels, and calculated multifunctionality. Plant species richness and functional diversity both increased multifunctionality, but their effects were context dependent. Species richness increased multifunctionality, but only when communities were assembled with fast growing (high SLA) species. This was because slow species were more redundant in their functional effects, whereas fast species tended to promote different functions. Functional diversity also increased multifunctionality but this effect was dampened by nitrogen enrichment, however, unfertilised, functionally diverse communities still delivered more functions than low diversity, fertilised communities. Our study suggests that a shift towards exploitative communities will not only alter ecosystem functioning but also the strength of biodiversity-functioning relationships, which highlights the potentially complex effects of global change on multifunctionality.

scholarly journals Response of water fluxes and biomass production to climate change in permanent grassland soil ecosystems

2021 ◽  
Vol 25 (12) ◽  
pp. 6087-6106
Author(s):  
Veronika Forstner ◽  
Jannis Groh ◽  
Matevz Vremec ◽  
Markus Herndl ◽  
Harry Vereecken ◽  
...  
Keyword(s):  
Climate Change ◽  
Elevated Temperature ◽  
Biomass Production ◽  
Aboveground Biomass ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Actual Evapotranspiration ◽  
Water Fluxes ◽  
Permanent Grassland ◽  
Experimental Approaches

Abstract. Effects of climate change on the ecosystem productivity and water fluxes have been studied in various types of experiments. However, it is still largely unknown whether and how the experimental approach itself affects the results of such studies. We employed two contrasting experimental approaches, using high-precision weighable monolithic lysimeters, over a period of 4 years to identify and compare the responses of water fluxes and aboveground biomass to climate change in permanent grassland. The first, manipulative, approach is based on controlled increases of atmospheric CO2 concentration and surface temperature. The second, observational, approach uses data from a space-for-time substitution along a gradient of climatic conditions. The Budyko framework was used to identify if the soil ecosystem is energy limited or water limited. Elevated temperature reduced the amount of non-rainfall water, particularly during the growing season in both approaches. In energy-limited grassland ecosystems, elevated temperature increased the actual evapotranspiration and decreased aboveground biomass. As a consequence, elevated temperature led to decreasing seepage rates in energy-limited systems. Under water-limited conditions in dry periods, elevated temperature aggravated water stress and, thus, resulted in reduced actual evapotranspiration. The already small seepage rates of the drier soils remained almost unaffected under these conditions compared to soils under wetter conditions. Elevated atmospheric CO2 reduced both actual evapotranspiration and aboveground biomass in the manipulative experiment and, therefore, led to a clear increase and change in seasonality of seepage. As expected, the aboveground biomass productivity and ecosystem efficiency indicators of the water-limited ecosystems were negatively correlated with an increase in aridity, while the trend was unclear for the energy-limited ecosystems. In both experimental approaches, the responses of soil water fluxes and biomass production mainly depend on the ecosystems' status with respect to energy or water limitation. To thoroughly understand the ecosystem response to climate change and be able to identify tipping points, experiments need to embrace sufficiently extreme boundary conditions and explore responses to individual and multiple drivers, such as temperature, CO2 concentration, and precipitation, including non-rainfall water. In this regard, manipulative and observational climate change experiments complement one another and, thus, should be combined in the investigation of climate change effects on grassland.

Aboveground Biomass Production of Cenchrus ciliaris in Tunisian Arid Zone

2007 ◽  
Vol 7 (6) ◽  
pp. 985-988 ◽  
Author(s):  
Idi Abdelkader ◽  
Ali Ferchichi . ◽  
Mohamed Chaieb .
Keyword(s):  
Biomass Production ◽  
Aboveground Biomass ◽  
Arid Zone ◽  
Cenchrus Ciliaris
Sign in / Sign up

Export Citation Format

Share Document