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.

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 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.

Yield and partitioning in crops of contrasting cultivars of winter wheat in response to CO2 and temperature in field studies using temperature gradient tunnels

1998 ◽  
Vol 130 (1) ◽  
pp. 17-27 ◽  
Author(s):  
G. R. BATTS ◽  
R. H. ELLIS ◽  
J. I. L. MORISON ◽  
P. N. NKEMKA ◽  
P. J. GREGORY ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Winter Wheat ◽  
Grain Yield ◽  
Biomass Yield ◽  
Field Studies ◽  
Dry Mass ◽  
Seasonal Temperature ◽  
Above Ground Biomass ◽  
Maximum Benefit ◽  
The Impact

Diverse cultivars of winter wheat (Triticum aestivum L.) were grown in the field in 1993/94 and 1994/95 at Reading UK in temperature gradient tunnels at normal atmospheric (c. 370) or elevated CO2 concentration (c. 700 μmol CO2 mol−1 air). In 1993/94, grain yield of cv. Avalon was insensitive to mean temperature (between 8·8 and 10·9°C), while elevated CO2 increased yield by 1·3 t ha−1 (12·6%). In all other cultivars, warming reduced grain yield and CO2 increased grain yield. In 1993/94, in cvs Galahad and Mercia the effects of CO2 and temperature on yield were additive. However, for cv. Hereward in both years and for cv. Soissons in 1994/95, there were negative interactions between the effects of CO2 and temperature on yield: the maximum benefit of doubling CO2 to grain yield, 4·5 and 2·7 t ha−1 (65 and 29%) respectively, occurred at cooler temperatures; there was no benefit from doubling CO2 (i.e. 0%) once the temperature had increased above the seasonal mean by 2·2–2·6°C in cv. Hereward and by 1·3°C in cv. Soissons. The beneficial effect of doubling CO2 on grain yield in cvs Galahad, Hereward, Mercia and Soissons was negated by an increase in mean seasonal temperature of only 0·7–2·0°C. Warming decreased root dry mass at anthesis in 1994/95 while it increased at elevated CO2 (49 and 186%, coolest and warmest regime, respectively). Carbon partitioned to roots declined progressively with warming, while at elevated CO2 there was an average of 56% increase in allocation to roots. The relative impacts of both CO2 and temperature were greater on root dry mass than on either grain yield or total above-ground biomass, while the effects on grain and biomass yield varied considerably between cultivars, suggesting that the impact of rising CO2 and temperature are likely to be dependent on cultivar.

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.

scholarly journals Influence of rhizome mass on the crop establishment and dry matter yield of Miscanthus×giganteus over ten seasons

2019 ◽  
Vol 64 (1) ◽  
pp. 21-35
Author(s):  
Zeljko Dzeletovic ◽  
Gordana Andrejic ◽  
Aleksandar Simic ◽  
Hakan Geren
Keyword(s):  
Biomass Yield ◽  
Planting Density ◽  
Above Ground Biomass ◽  
Ground Biomass ◽  
Miscanthus Giganteus ◽  
Medium Mass ◽  
Biomass Yields ◽  
Low Mass ◽  
Number Of Stems ◽  
High Yields

The aim of the present investigation was to assess the influence of rhizome mass on the success of plantation establishment and biomass yield of the bioenergy crop M. ? giganteus during 10 years of cultivation. The experiment included three treatments with different rhizome masses: 10-20 g (very low); 25- 35 g (low), and 40-60 g (medium mass). Planting density was 2 rhizomes m-2. The plants were harvested by mowing of the whole above-ground biomass each year in February. Out of the total number of planted rhizomes, the lowest emergence was noticed in very low mass rhizomes. In the first season, the greatest number of stems and crop height were encountered under the treatment with the highest rhizome mass. In the second season, crop heights were almost equal in all treatments. During the first two seasons, the highest biomass yields were recorded under the treatments with the highest rhizome masses. Although the analyzed parameters were highest with the rhizomes of 40-60g during the crop establishing stage, starting from the third season of cultivation, high yields of above-ground biomass may be obtained also with lower mass rhizomes. Having the highest biomass yield (25.85?7.36 Mg DM ha-1), the crop established with rhizomes of 25-35 g clearly stood out.

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.

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
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