Impacts of long-term nitrogen addition, watering and mowing on ammonia oxidizers, denitrifiers and plant communities in a temperate steppe

2018 ◽  
Vol 130 ◽  
pp. 241-250 ◽  
Author(s):  
Cui-Jing Zhang ◽  
Zhong-Ling Yang ◽  
Ju-Pei Shen ◽  
Yi-Fei Sun ◽  
Jun-Tao Wang ◽  
...  
2012 ◽  
pp. 66-77 ◽  
Author(s):  
I. A. Lavrinenko ◽  
O. V. Lavrinenko ◽  
D. V. Dobrynin

The satellite images show that the area of marshes in the Kolokolkova bay was notstable during the period from 1973 up to 2011. Until 2010 it varied from 357 to 636 ha. After a severe storm happened on July 24–25, 2010 the total area of marshes was reduced up to 43–50 ha. The mean value of NDVI for studied marshes, reflecting the green biomass, varied from 0.13 to 0.32 before the storm in 2010, after the storm the NDVI decreased to 0.10, in 2011 — 0.03. A comparative analysis of species composition and structure of plant communities described in 2002 and 2011, allowed to evaluate the vegetation changes of marshes of the different topographic levels. They are fol­lowing: a total destruction of plant communities of the ass. Puccinellietum phryganodis and ass. Caricetum subspathaceae on low and middle marches; increasing role of halophytic species in plant communities of the ass. Caricetum glareosae vic. Calamagrostis deschampsioides subass. typicum on middle marches; some changes in species composition and structure of plant communities of the ass. Caricetum glareosae vic. Calamagrostis deschampsioides subass. festucetosum rubrae on high marches and ass. Parnassio palustris–Salicetum reptantis in transition zone between marches and tundra without changes of their syntaxonomy; a death of moss cover in plant communities of the ass. Caricetum mackenziei var. Warnstorfia exannulata on brackish coastal bogs. The possible reasons of dramatic vegetation dynamics are discussed. The dating of the storm makes it possible to observe the directions and rates of the succession of marches vegetation.


2015 ◽  
Vol 27 (3) ◽  
pp. 621-629 ◽  
Author(s):  
Junqiang Jia ◽  
Yunshe Dong ◽  
Yuchun Qi ◽  
Qin Peng ◽  
Xinchao Liu ◽  
...  

Koedoe ◽  
2008 ◽  
Vol 50 (1) ◽  
Author(s):  
Robert F. Brand ◽  
Pieter J. Du Preez ◽  
Leslie R. Brown

Within the Platberg area and the wider Drakensberg region, the shrinking natural resources and the threat posed to biodiversity are of concern to conservation management and require an understanding of long-term ecological processes. The vegetation of Platberg was investigated as part of an ecological survey to establish Afromontane floristic links to the Drakensberg as well as for the management of natural resources. From a TWINSPAN classification, refined by the Braun-Blanquet method, four main plant communities were identified, which were subdivided into fynbos, wetland, a woody/shrub community and grassland. A classification and description of the fynbos are presented in this article.The analysis showed the fynbos divided into two communities comprising four sub-communities and seven variants. The fynbos community had an average of 28.34 species per relevé, ranging from 14 to 54 species per sample plot. Twenty-four endemic or near-endemic Drakensberg Alpine Centre (DAC) species and 22 exotic (alien-invasive) species were recorded. Numerous floristic links with the DAC, Cape flora fynbos and grassland bioregions to the north and west were also found. The description of the fynbos plant communities can serve as a basis for the formulation of management plans for the area.


2014 ◽  
Vol 94 (1) ◽  
pp. 33-39 ◽  
Author(s):  
D. J. Thompson ◽  
W. D. Willms

Thompson, D. J. and Willms, W. D. 2014. Effects of long-term protection from grazing on phenotypic expression in geographically separated mountain rough fescue populations. Can. J. Plant Sci. 94: 33–39. Whether or not long-term grazing or protection from grazing alters the genetic makeup of grass populations has been debated. Mountain rough fescue [(Festuca campestris (Rydb.)], which is highly sensitive to summer grazing, and becomes dominant in plant communities with long-term protection, was chosen to address this question. Plants from three geographic sites (Stavely in AB, Milroy in the Kootenay trench, BC and Goose Lake on the BC interior plateau) with divergent grazing histories were vegetatively propagated from tillers. Daughter plants were planted into two field nurseries (at Kamloops, BC, and Stavely, AB) and morphological measurements were taken in two field seasons post-establishment. Plants from all three populations were taller, flowered earlier, and were more productive at the Kamloops nursery site. Of the three geographic sources, plants from the Goose Lake site were most distinct with narrower leaves, later flowering, and greater yield. Plants with a long history of grazing had slightly shorter fertile tillers and leaves than plants with a history of long-term protection.


Koedoe ◽  
2004 ◽  
Vol 47 (2) ◽  
Author(s):  
G. Cleaver ◽  
L.R. Brown ◽  
G.J. Bredenkamp

The Kammanassie Mountain is a declared mountain catchment area and a Cape mountain zebra Equus zebra zebra population is preserved on the mountain. The high number of springs on the mountain not only provides water for the animal species but also contributes to overall ecosystem functioning. Long-term conservation of viable ecosystems requires a broader understanding of the ecological processes involved. It was therefore decided that a classification, description and mapping of the spring vegetation of the Kammanassie Mountain be undertaken. A TWINSPAN classification, refined by Braun-Blanquet procedures, revealed 11 major plant communities that could be related to geological origin. Habitat factors associated with differences in vegetation include topography, soil type and grazing. Descriptions of the plant communities include diagnostic species as well as prominent and less conspicuous species of the tree, shrub and herbaceous layers. The results also indicate a high species richness compared to similar regions and the difference between plant communities of wet and dry springs. This data is important for long-term monitoring of the spring ecosystems as well as for the compilation of management plans.


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