Maximum flood depth characterizes above-ground biomass in African seasonally shallowly flooded grasslands

2007 ◽  
Vol 23 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Paul Scholte
Keyword(s):  
Dry Season ◽  
Perennial Grasses ◽  
Individual Species ◽  
Above Ground Biomass ◽  
Nutrient Quality ◽  
Flood Duration ◽  
Ground Biomass ◽  
Flood Depth ◽  
The Individual ◽  
The Impact

Flood depth has been frequently used to explain the distribution of plant species in seasonally flooded grasslands, but its relation with vegetation production has remained ambiguous. The relationship between flooding and above-ground biomass at the end of the flooding season and during the dry season was studied to assess the impact of reflooding on the Logone floodplain, Cameroon. Above-ground biomass of a combination of all species and of the individual perennial grasses Oryza longistaminata and Echinochloa pyramidalis showed a positive linear relationship with maximum flood depth up to 1 m. The gradient of these relationships became steeper and their fit better during the 2 y following the installation of the flooding, showing the response lag to floodplain rehabilitation. Flood duration only explained the above-ground biomass of the combination of all species and not of the individual species. Above-ground biomass data from other floodplains in the three main African geographic regions showed a similar relationship with maximum flood depth less than 1 m. Dry-season regrowth, important because of its high nutrient quality during forage scarcity, was not directly related to maximum flood depth, possibly because of its dependency on the period of burning and soil moisture. Presented data indicate that a rise of water level of 1 cm corresponds to an increase in above-ground biomass of c. 150 kg DM ha−1.

scholarly journals Opposite effects of nutrient enrichment and herbivory by an alien snail on growth of an invasive macrophyte and native macrophytes

2021 ◽  
Author(s):  
Yimin Yan ◽  
Ayub M.O. Oduor ◽  
Feng Li ◽  
Yonghong Xie ◽  
Yanjie Liu
Keyword(s):  
Nutrient Enrichment ◽  
Animal Species ◽  
Biomass Yield ◽  
Freshwater Ecosystems ◽  
Pomacea Canaliculata ◽  
Above Ground Biomass ◽  
Aquatic Habitats ◽  
Ground Biomass ◽  
Invasive Spread ◽  
The Impact

Human-mediated introduction of plant and animal species into biogeographic ranges where they did not occur before has been so pervasive globally that many ecosystems are now co-invaded by multiple alien plant and animal species. Although empirical evidence of invaders modifying recipient ecosystems to the benefit of other aliens is accumulating, these interactions remain underexplored and underrepresented in heuristic models of invasion success. Many freshwater ecosystems are co-invaded by aquatic macrophytes and mollusks and at the same time experience nutrient enrichment from various sources. However, studies are lacking that test how nutrient enrichment and co-invasion by alien herbivores and plant species can interactively affect native plant communities in aquatic habitats. To test such effects, we performed a freshwater mesocosm experiment in which we grew a synthetic native macrophyte community of three species under two levels of nutrient enrichment (enrichment vs. no-enrichment) treatment and fully crossed with two levels of competition from an invasive macrophyte Myriophyllum aquaticum (competition vs. no-competition), and two levels of herbivory by an invasive snail Pomacea canaliculata (herbivory vs. no-herbivory) treatments. Results show that herbivory by the invasive snail enhanced above-ground biomass yield of the invasive macrophyte. Moreover, the invasive herbivore preferentially fed on biomass of the native macrophytes over that of the invasive macrophyte. However, nutrient enrichment reduced above-ground biomass yield of the invasive macrophyte. Our results suggest that eutrophication of aquatic habitats that are already invaded by M. aquaticum may slow down invasive spread of the invasive macrophyte. However, herbivory by the invasive snail P. canaliculata may enhance invasive spread of M. aquaticum in the same habitats. Broadly, our study underscores the significance of considering several factors and their interaction when assessing the impact of invasive species, especially considering that many habitats experience co-invasion by plants and herbivores and simultaneously undergo varous other disturbances including nutrient enrichment.

scholarly journals Impact of tidal height on characteristics of ALOS PALSAR measurements to estimate above ground biomass of mangrove forest in Indonesia

2018 ◽  
Author(s):  
Ketut Wikantika
Keyword(s):  
Mangrove Forest ◽  
Impact Analysis ◽  
Time Series Data ◽  
Tidal Height ◽  
Series Data ◽  
Above Ground Biomass ◽  
Large Area ◽  
Alos Palsar ◽  
Ground Biomass ◽  
The Impact

Mangrove has the most carbon rich forests in the tropics. Mapping and monitoring biomass of mangrove forest is very important to manage ecosystem and field survey of mangrove biomass and productivity is very difficult due to muddy soil condition, heavy weight of the wood, very large area and tidal effect on mangrove area. Advanced Land Observing Satellite (ALOS) Phased Array L-band Synthetic Aperture Radar (PALSAR) is available for identification and monitoring mangrove forest. The objective of this research is to investigate the impact of tidal height on characteristics of HH and HV derived from ALOS PALSAR for estimation above ground biomass of mangrove forest. Methodology consists of collecting of tidal height data in the study area, ALOS-PALSAR time series data, region of interest (ROI) on mangrove forest, characterization of HH and HV and impact analysis of tidal height on HH and HV. The result of this research has showed the impact of tidal height on characteristics HH and HV on mangrove forest types derived from ALOS-PALSAR and proposed the model for estimation aboveground biomass of mangrove forest.

scholarly journals Plant communities responding to grazing pressure by sheep in an Alpine meadow

2020 ◽  
Vol 4 (2) ◽  
pp. 1174-1181
Author(s):  
Jianping Wu ◽  
Xuyin Gong ◽  
Xixi Yao ◽  
David P Casper
Keyword(s):  
Plant Communities ◽  
Nutritional Quality ◽  
Nutritional Value ◽  
Net Primary Production ◽  
Average Daily Gain ◽  
Livestock Grazing ◽  
Grassland Ecosystem ◽  
Above Ground Biomass ◽  
Ground Biomass ◽  
The Impact

Abstract The Chinese grassland ecosystem is an important national asset that not only impacts climate regulation, soil and water conservation, wind protection, and soil carbon and nitrogen fixation but is also an important contributor to maintaining grassland biodiversity while supporting livestock production. Grasslands are a key component contributing to the productivity of grazing animals but also provide basic food production via livestock grazing for herder survival. Grazing is the most basic means of grassland utilization but is considered one of the more important disturbance factors controllable by humans that has a universal and profound impact on the grassland ecosystem due to animal density and over grazing. For Alpine grasslands, it is not clear what grazing intensity (GI) can be achieved to improve plant biodiversity and vegetative nutritional value while improving sheep productivity. This field experiment was conducted for 7 yr comparing the impact of different GI on vegetation community characteristics, nutritional value, and sheep growth performance on the Alpine meadows of the Qinghai–Tibetan Plateau. The GI measured were: Control: 0 sheep/ha; Low: 3.7 sheep/ha; Medium: 5.3 sheep/ha; and Heavy: 7.6 sheep/ha. The grazing experiment started in 2008, but experimental data collection and analyses were collected for the final 4 yr of 2015 through 2018. All grazing intensities >0 sheep/ha reduced (P < 0.05) plant height (27%, 46%, and 48%, respectively, for 3.7, 5.3, and 7.6 sheep/ha), ground coverage (16%, 24%, and 48%), and above ground biomass (2%, 42% and 53%) of the various plant communities while increasing (P < 0.05) the grass community density (individuals/m2) compared to a nongrazed Control. With increasing GI, the community height, coverage, and above-ground biomass decreased (P < 0.05), and the plant community density increased then decreased (P < 0.05) compared to Control. As GI increased, the available community biomass nutritional quality increased (P < 0.05). Comprehensive analysis showed that the community density (quantity) and nutritional quality were the highest when the GI was 5.3 sheep/ha. The higher the GI, the greater the grass’s nutritive value with lower above-ground net primary production (ANPP). When GI was the highest, the average daily gain (ADG) per hectare was the highest in the short term, but the highest GI endangers the ANPP and profitability of the grassland grazing ecosystem in the long term. Targeting a moderate GI (5.3 sheep/ha) can provide 78% of the ADG per hectare of the highest GI, which meets the requirement of maintaining a sustainable grazing grassland.

Methodology to Evaluate the Characteristics of a Twin-Scroll Turbocharger With Various Approaches for the Computation of Thermodynamic Properties

2017 ◽  
Author(s):  
Holger Mai ◽  
André Kaufmann
Keyword(s):  
Thermodynamic Properties ◽  
Test Bench ◽  
Good Practice ◽  
Working Fluid ◽  
Individual Species ◽  
Quality Level ◽  
Humid Air ◽  
Hot Gas ◽  
The Individual ◽  
The Impact

When it comes to evaluating the thermodynamic and fluid dynamic behavior of a turbocharger (TC) and ensuring the best possible matching to the internal combustion engine, a precise measurement of the characteristic maps is required. Measured on a hot-gas test bench under steady-state conditions, the maps of the compressor and turbine give detailed information about the turbocharger performance and provide boundary conditions for simulating the engine processes of a turbocharged engine. At the moment there is no comprehensive standard on how to measure a TC on a test bench. All existing guidelines such as SAE J1826 & J922 and ASME PTC 10 contain more general information with recommendations, but turbocharger mapping on a hot-gas test bench is highly complex and has a large dependence on heat transfer. The characteristics are not determined directly, but have to be computed using the measured quantities and the thermodynamic properties of the working fluid. For that reason, all influences that may occur during the measurement have to be taken into account for the comparability of different turbochargers or the repeatability for the same turbocharger specimen. As a consequence, this paper deals with the methodology of thermodynamic computation for a mono-scroll and a twin-scroll turbocharger in general and the impact of different approaches for computing the thermodynamic properties of the individual species on compressor and turbine efficiencies in particular. For computing the characteristics of a mono-scroll turbocharger, a methodology is used that matches good practice and state-of-the-art technology. For computing the characteristics of a twin-scroll turbocharger, a new methodology is developed to provide a practical approach for the evaluation of pressure ratios and efficiencies of a twin-entry turbine. The use of the closed-loop unit for the extension of the turbine is included. Computing the thermodynamic state changes, power, and efficiencies of the compressor and turbine requires knowledge of the physicochemical properties of the involved fluids. These fluids are humid air (compressor) and exhaust gas (turbine) and depend on the gas composition, pressure, and especially temperature with respect to the relative humidity. Turbocharger efficiencies are very sensitive to deviations in the thermodynamic properties of the individual species. Different forms of polynomials with different levels of complexity and precision are available in literature. In this paper, the most commonly used polynomials for computing the thermodynamic properties such as caloric perfect gas, humid air, VDI 4670, NASA9, CHEMKIN, NIST, and SAE J1826 will be used for the characteristic maps of a twin-scroll turbocharger. The results will be discussed in terms of the impact on turbocharger efficiencies and the relevance to achieving a desired quality level for turbocharger mapping.

scholarly journals Microbiome interactions shape host fitness

2018 ◽  
Vol 115 (51) ◽  
pp. E11951-E11960 ◽  
Author(s):  
Alison L. Gould ◽  
Vivian Zhang ◽  
Lisa Lamberti ◽  
Eric W. Jones ◽  
Benjamin Obadia ◽  
...  
Keyword(s):  
Life History ◽  
Bacterial Species ◽  
Gut Bacteria ◽  
Individual Species ◽  
Multiple Traits ◽  
Community Interactions ◽  
Host Fitness ◽  
Core Species ◽  
The Individual ◽  
The Impact

Gut bacteria can affect key aspects of host fitness, such as development, fecundity, and lifespan, while the host, in turn, shapes the gut microbiome. However, it is unclear to what extent individual species versus community interactions within the microbiome are linked to host fitness. Here, we combinatorially dissect the natural microbiome of Drosophila melanogaster and reveal that interactions between bacteria shape host fitness through life history tradeoffs. Empirically, we made germ-free flies colonized with each possible combination of the five core species of fly gut bacteria. We measured the resulting bacterial community abundances and fly fitness traits, including development, reproduction, and lifespan. The fly gut promoted bacterial diversity, which, in turn, accelerated development, reproduction, and aging: Flies that reproduced more died sooner. From these measurements, we calculated the impact of bacterial interactions on fly fitness by adapting the mathematics of genetic epistasis to the microbiome. Development and fecundity converged with higher diversity, suggesting minimal dependence on interactions. However, host lifespan and microbiome abundances were highly dependent on interactions between bacterial species. Higher-order interactions (involving three, four, and five species) occurred in 13–44% of possible cases depending on the trait, with the same interactions affecting multiple traits, a reflection of the life history tradeoff. Overall, we found these interactions were frequently context-dependent and often had the same magnitude as individual species themselves, indicating that the interactions can be as important as the individual species in gut microbiomes.

The impact of selective logging and clearcutting on forest structure, tree diversity and above-ground biomass of African tropical forests

2014 ◽  
Vol 30 (1) ◽  
pp. 119-132 ◽  
Author(s):  
Roberto Cazzolla Gatti ◽  
Simona Castaldi ◽  
Jeremy A. Lindsell ◽  
David A. Coomes ◽  
Marco Marchetti ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Forest Structure ◽  
Tree Diversity ◽  
Selective Logging ◽  
Above Ground Biomass ◽  
Ground Biomass ◽  
Structure Tree ◽  
The Impact

Effect of Organic Manures, Azotobacter and Spacing on Yield of Solanum nigrum L.

2015 ◽  
Vol 22 (3) ◽  
pp. 133-137
Author(s):  
Ashwani Kumar ◽  
Kulwant Sharma
Keyword(s):  
Root Biomass ◽  
Biomass Yield ◽  
Solanum Nigrum ◽  
Above Ground Biomass ◽  
Organic Manures ◽  
Ground Biomass ◽  
Yield Parameters ◽  
Maximum Value ◽  
Solanum Nigrum L ◽  
The Impact

The present investigation on effect of organic manures, Azotobacter and spacing on yield of Solanum nigrum L. was carried out. Seven different treatments with three spacings were studied to observe the impact of these treatments on yield parameters. Overall, treatment of Vermicompost + Azotobacter combination at S3 (45x45 cm) spacing gave maximum seed yield/plant, fresh above ground biomass per plant, fresh root biomass per plant, dry above ground biomass per plant, dry root biomass per plant as compared to other treatments at different spacings. Maximum value for yield parameters viz. total fresh biomass yield and total dry biomass yield/ha were recorded in treatment of Vermicompost + Azotobacter combination at with 30 x 30 cm spacing. The yield decreased with the further increase in spacing.

scholarly journals Above Ground Biomass Estimation of Syzygium aromaticum using structure from motion (SfM) derived from Unmanned Aerial Vehicle in Paninggahan Agroforest Area, West Sumatra

2021 ◽  
Vol 9 (1) ◽  
pp. 39
Author(s):  
Try Surya Harapan ◽  
Ahsanul Husna ◽  
Thoriq Alfath Febriamansyah ◽  
Mahdi Mutashim ◽  
Andri Saputra ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Aerial Image ◽  
Biomass Estimation ◽  
Syzygium Aromaticum ◽  
Above Ground Biomass ◽  
Ground Biomass ◽  
West Sumatra ◽  
Aerial Vehicle ◽  
The Difference ◽  
The Individual

Above ground biomass (AGB) is all living organic matters above the soil including stem, seed and leaves. This study aimed to estimate the individual clove (Syzygium aromaticum) and it’s above ground biomass using Unmanned Aerial Vehicle in the Agroforestry area in Paninggahan, West Sumatra. This study used a photogrammetry method to calculate trees and estimated the AGB. We detected 257 numbers of trees based on aerial image analysis and observed 270 after we validated on ground check in the field. The result was slightly different between estimated AGB from UAV and observed AGB from our ground validation. The estimated AGB was 5.9 ton/ Ha where the surveyed AGB was 5.6 ton/Ha. The difference between estimated AGB and observed AGB was 0.3 ton/Ha.

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