Diversity, dominance, stability, and net production in the grasslands at Varanasi, India

1969 ◽  
Vol 47 (3) ◽  
pp. 425-427 ◽  
Author(s):  
J. S. Singh ◽  
R. Misra
Keyword(s):  
Species Diversity ◽  
Productive Efficiency ◽  
Community Stability ◽  
Net Production

A study conducted on the grassland of Varanasi (Tropical), has shown that species diversity increases productive efficiency of the ecosystem while dominance makes the system stable, though less efficient for production. These results are contradictory to McNaughton's observation that diversity decreases efficiency and generates community stability, and thus call for further work before generalization for all situations can be drawn.

scholarly journals Resource enrichment combined with biomass removal maintains plant diversity and community stability in a long-term grazed grassland

2020 ◽  
Vol 13 (5) ◽  
pp. 611-620
Author(s):  
Feng-Wei Xu ◽  
Jian-Jun Li ◽  
Li-Ji Wu ◽  
Xiao-Ming Lu ◽  
Wen Xing ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Plant Diversity ◽  
Primary Productivity ◽  
Management Practices ◽  
Light Exposure ◽  
Community Stability ◽  
Water Addition ◽  
Biomass Removal

Abstract Aims Long-term heavy grazing reduces plant diversity and ecosystem function by intensifying nitrogen (N) and water limitation. In contrast, the absence of biomass removal can cause species loss by elevating light competition and weakening community stability, which is exacerbated by N and water enrichment. Hence, how to maintain species diversity and community stability is still a huge challenge for sustainable management of worldwide grasslands. Methods We conducted a 4-year manipulated experiment in six long-term grazing blocks to explore combination of resource additions and biomass removal (increased water, N and light availability) on species richness and community stability in semiarid grasslands of Inner Mongolia, China. Important Findings In all blocks treated with the combination of resource additions and biomass removal, primary productivity increased and species richness and community stability were maintained over 4 years of experiment. At both species and plant functional group (PFG) levels, the aboveground biomass of treated plants remained temporally stable in treatments with the combination of N and/or water addition and biomass removal. The maintenance of species richness was primarily caused by the biomass removal, which could increase the amount of light exposure for grasses under resource enrichment. Both species asynchrony and stability of PFGs contributed to the high temporal stability observed in these communities. Our results indicate that management practices of combined resource enrichment with biomass removal, such as grazing or mowing, could not only enhance primary productivity but also maintain plant species diversity, species asynchrony and community stability. Furthermore, as overgrazing-induced degradation and resource enrichment-induced biodiversity loss continue to be major problems worldwide, our findings have important implications for adaptive management in semiarid grasslands and beyond.

scholarly journals Species traits and species diversity affect community stability in a multiple stressor framework

2012 ◽  
Vol 17 (3) ◽  
pp. 197-209 ◽  
Author(s):  
S Flöder ◽  
H Hillebrand
Keyword(s):  
Species Diversity ◽  
Species Traits ◽  
Community Stability ◽  
Multiple Stressor

scholarly journals Community Structure and Soil Mineral Concentration in Relation to Plant Invasion in a Subtropical Urban and Rural Ecotone

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 185
Author(s):  
Peiyun Xie ◽  
Ting Liu ◽  
Hongyu Chen ◽  
Zhiyao Su
Keyword(s):  
Community Structure ◽  
Species Diversity ◽  
Alien Species ◽  
Plant Management ◽  
Mineral Element ◽  
Community Stability ◽  
Soil Mineral ◽  
Species Invasion ◽  
Element Concentrations ◽  
Alien Species Invasion

Alien species invasion affects local community biodiversity and stability considerably, and ecosystem services and functions will accordingly be dramatically changed. Many studies have reported a correlation between invasibility and the chemical nature of soil, but the influences of understory plant community structure and soil trace element concentrations on invasibility have not been fully explored. Landscape heterogeneity in the urban and rural ecotone may alter the invasion process, and assessing the invasibility of different types of native forests may lead to a better understanding of the mechanisms by which native species resist invasion. We compared the composition, structure, diversity and stability of the understory community in abandoned fallows, severely invaded by Mikania micrantha and Borreria latifolia, and adjacent natural and planted forests in the urban and rural ecotone of Eastern Guangzhou, China. Additionally, we quantified mineral element concentrations in the topsoil (0–25 cm) most influenced by the root system of understory communities in the forest stand types. Abandoned fallows had the highest concentrations of available ferrum (Fe) and available boron (B) and the lowest concentration of total mercury (Hg) Hg among the three stand types. In contrast to various species diversity indices, the understory structure of the three stands better explained differences in community invasibility. Average understory cover significantly differed among the three stand types, and those types with the greatest number of stems in height and cover classes 1 and 2 differed the most, indicating that seedling establishment may deter invasion to a certain extent. CCA (canonical correspondence analysis) results better reflected the distribution range of each stand type and its relationship with environmental factors, and available Fe, available B, exchangeable calcium (Ca), exchangeable magnesium (Mg), cover, available copper (Cu) and total Hg , were strongly related the distribution of native and exotic understory species. Invasion weakened community stability. The stability index changed consistently with the species diversity index, and abandoned fallows understory community stability was lower than the other stand types. According to our results, both soil mineral element concentrations and community structure are related to alien species invasion. Against the backdrop of urbanization and industrialization, this information will provide forest management and planning departments with certain reference points for forest protection and invasive plant management.

Improving the productive efficiency of electric resistance weld tube mills

1960 ◽  
Vol 39 (6) ◽  
pp. 357
Author(s):  
E.J. Swinn
Keyword(s):  
Productive Efficiency ◽  
Electric Resistance ◽  
Resistance Weld

Species diversity, abundance, biomass, size and trophic structure of fish on coral reefs in relation to shark abundance

2017 ◽  
Vol 565 ◽  
pp. 163-179 ◽  
Author(s):  
SC Barley ◽  
MG Meekan ◽  
JJ Meeuwig
Keyword(s):  
Species Diversity ◽  
Coral Reefs ◽  
Trophic Structure

Diatoms in the Early Valdai (Weichselian) sediments in Lake Ladoga basin

2019 ◽  
pp. 225-228
Author(s):  
Anna V. Ludikova
Keyword(s):  
Species Diversity ◽  
High Energy ◽  
Lake Ladoga ◽  
Diatom Assemblages ◽  
Marine Diatoms ◽  
Selective Preservation

The pioneer diatom study of the Early Weichselian (Valdai) sediments in Lake Ladoga basin was performed. The specifics of the diatom assemblages (co-occurrence of ecologically incompatible taxa, poor species diversity, low diatom concentration and selective preservation) suggest that during the Early Weichselian time intense erosion of previously deposited marine Eemian (Mikulino) sediments prevailed, which resulted in re-deposition of marine diatoms. The sedimentation took place in high-energy environments unfavorable for diatom accumulation and preservation.

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