scholarly journals Riparian Vegetation Density Mapping of an Extremely Densely Vegetated Confined Floodplain

Hydrology ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 176
Author(s):  
István Fehérváry ◽  
Tímea Kiss
Keyword(s):  
Riparian Vegetation ◽  
Woody Species ◽  
Submerged Vegetation ◽  
Vegetation Types ◽  
Vegetation Density ◽  
Vegetation Zone ◽  
Density Mapping ◽  
Vegetation Zones ◽  
Branch Density ◽  
Vegetation Patches

The most crucial function of lowland-confined floodplains with low slopes is to support flood conveyance and fasten floods; however, obstacles can hinder it. The management of riparian vegetation is often neglected, though woody species increase the vegetation roughness of floodplains and increase flood levels. The aims are (1) to determine the branch density of various riparian vegetation types in the flood conveyance zone up to the level of artificial levees (up to 5 m), and (2) to assess the spatial distribution of densely vegetated patches. Applying a decision tree and machine learning, six vegetation types were identified with an accuracy of 83%. The vegetation density was determined within each type by applying the normalized relative point density (NRD) method. Besides, vegetation density was calculated in each submerged vegetation zone (1–2 m, 2–3 m, etc.). Thus, the obstacles for floods with various frequencies were mapped. In the study area, young poplar plantations offer the most favorable flood conveyance conditions, whereas invasive Amorpha thickets and the dense stands of native willow forests provide the worst conditions for flood conveyance. Dense and very dense vegetation patches are common in all submerged vegetation zones; thus, vegetation could heavily influence floods.

scholarly journals Numerical modeling of the hydraulic impact of riparian vegetation

2018 ◽  
Vol 44 ◽  
pp. 00194
Author(s):  
Krzysztof Wolski ◽  
Tomasz Tymiński ◽  
Grzegorz Chrobak
Keyword(s):  
Numerical Modeling ◽  
Riparian Vegetation ◽  
Water Surface ◽  
Numerical Models ◽  
Three Dimensional ◽  
Careful Examination ◽  
Impact Structure ◽  
Hydraulic Impact ◽  
Vegetation Zones ◽  
Maximal Shear Stress

This paper presents results of numerical modelling of riverbed segment with riparian vegetation performed with use of CCHE2 software. Vegetation zones are places where dynamic of water flow increases. Therefore, there is a need of careful examination of hydraulic impact structure of such zones. Accurate research is necessary and should be performed with use of physical or numerical models, two or three dimensional. Paper presents distribution of velocity and area of water surface for two variants of vegetation deposition acquired in CCHE2D software and modelled for riverbed with distinctive riparian vegetation. Results point to significant (30–40%) increase of maximal velocities in riverbed with riparian vegetation, while directly near the vegetation there were zones with very low velocities. Local damming occurs before vegetal zone. Maximal shear stress in zones with increased velocity is significantly augmented compared to conditions with no vegetation, which can cause more intensive erosion in those zones

Molecular identification of diazotroph microbial consortia in mountain soil

2010 ◽  
Vol 5 (5) ◽  
pp. 664-673 ◽  
Author(s):  
Rahela Carpa ◽  
Anca Butiuc-Keul ◽  
Cristina Dobrotă ◽  
Vasile Muntean
Keyword(s):  
Gene Diversity ◽  
Nifh Gene ◽  
Flood Plain ◽  
Soil Samples ◽  
Microbial Consortia ◽  
Nitrogen Fixing ◽  
Vegetation Zone ◽  
Vegetation Zones ◽  
Primer Sets ◽  
Nifh Genes

AbstractNitrogen fixing microbial consortia from soil samples taken from five altitudinal vegetation zones (alpine, subalpine, coniferous, beech, Maleia flood plain) of Parâng Massif, Romania, were isolated and identified. Molecular characterisation of nitrogen fixing consortia was carried out by PCR and nested PCR with 7 primer sets specific to nifH genes. All nifH genes are specific to nitrogen fixation and are found within phylogenetically related organisms which have the nitrogenase enzyme complex. These molecular studies allowed the assessment of nifH gene diversity within these nitrogen fixing microbial consortia from different type of soils. At high altitude, a consortium of nitrogen fixing bacteria dominated by Azotobacter chroococcum and Azospirillum brasilense was found. Clostridium, Rhizobiales, Herbaspirillum, Frankia species were also found in different rations depending on the altitudinal vegetation zone.

A Study on Complexity of Major Vegetation Types in China

2013 ◽  
Vol 864-867 ◽  
pp. 2459-2462
Author(s):  
Zong Han Li ◽  
Hua Yong Zhang ◽  
Fei Li ◽  
Xiang Xu
Keyword(s):  
Fractal Dimension ◽  
Vegetation Type ◽  
Alpine Vegetation ◽  
Vegetation Types ◽  
Forest Types ◽  
Vegetation Map ◽  
Tropical Mountains ◽  
The Relationship ◽  
Vegetation Patches ◽  
Dimension Index

In this study, fractal dimension index is applied to describe the complexity of 11 vegetation groups and 5 needle-leaf forest vegetation types in China. Basing on the Vegetation Map of China, we calculate the perimeter and area of vegetation patches with the software ArcGis. The relationship between perimeter and area is established for each vegetation group and vegetation type, and the corresponding fractal dimension index is estimated. The results show that, among the 11 vegetation groups, the Alpine vegetation is the most complex vegetation. In the 5 needle-leaf forest types, the subtropical and tropical mountains needle-leaf forest is the most complex vegetation. It seems that the complexity of vegetation is associated with altitude. The topography may be responsible for the complexity at different scales.

Effects of social behaviour on patch utilization by sheep in a complex vegetation mosaic

2005 ◽  
Vol 2005 ◽  
pp. 63-63
Author(s):  
A. M. Sibbald ◽  
S. P. Oom ◽  
R. J. Hooper ◽  
R. Anderson
Keyword(s):  
Social Interactions ◽  
Small Groups ◽  
Patch Size ◽  
Calluna Vulgaris ◽  
Heterogeneous Environments ◽  
Vegetation Types ◽  
The Relationship ◽  
Vegetation Mosaics ◽  
Vegetation Patches ◽  
Vegetation Mosaic

In heterogeneous environments, such as complex vegetation mosaics, there is likely to be a dynamic interaction between the spatial pattern of the vegetation and the distribution of the animals grazing there. Preferences for particular vegetation types will influence where animals choose to feed and, in turn, changes to the vegetation caused by damage from grazing and trampling will affect the dynamics of the mosaic. Social interactions, amongst highly social grazers such as sheep, can also affect the distribution of the animals, depending on the relationship between the dimensions of vegetation patches and the characteristic spacing of the animals. The aim of this study was to investigate the relationship between patch utilization and patch size for small groups of Scottish Blackface sheep foraging in a natural heather (Calluna vulgaris ) and grass mosaic.

Sensitivity of Modeled Channel Hydraulic Variables to Invasive and Native Riparian Vegetation

2017 ◽  
Vol 8 (4) ◽  
pp. 47-61 ◽  
Author(s):  
Adriana E. Martinez
Keyword(s):  
Invasive Species ◽  
Riparian Vegetation ◽  
Native Species ◽  
Plant Density ◽  
Dominant Role ◽  
Individual Species ◽  
Stream Velocity ◽  
Plant Characteristics ◽  
Vegetation Patches ◽  
Hydraulic Variables

Quantifying the roughness of riparian vegetation is important where it plays a dominant role by reducing water velocity. Vegetation roughness was calculated based on the plant characteristics of three dominant herbaceous plants, including one invasive, along the Sprague River, Oregon. E. palustris and invasive P. arundinacea exhibit higher and similar roughness values whereas C. vesicaria is lower. To determine differences, hydraulic channel conditions were modeled within NAYS 2DH. First, current conditions were modeled by populating the channel banks with roughness, plant density, and height of vegetation patches. Next, along the same reach, monocultures were modeled assuming dominance of individual species. In comparing the two native species to the invasive species, monoculture conditions show that plant density and roughness causes the native E. palustris to have the highest ability to decrease stream velocity. In areas where the invasive species is outcompeting E. palustris, such changes could cause increases in velocity and less stable bank surfaces.

Application and limitations of the Artemisia/Chenopodiaceae pollen ratio in arid and semi-arid China

The Holocene ◽  
2012 ◽  
Vol 22 (12) ◽  
pp. 1385-1392 ◽  
Author(s):  
Yan Zhao ◽  
Hongyan Liu ◽  
Furong Li ◽  
Xiaozhong Huang ◽  
Jinghui Sun ◽  
...  
Keyword(s):  
Arid Regions ◽  
Positive Relationship ◽  
Vegetation Types ◽  
Pollen Data ◽  
Data Synthesis ◽  
Modern Pollen ◽  
Vegetation Zones ◽  
Desert Areas ◽  
Vegetation And Climate ◽  
Semi Arid

The Artemisia/Chenopodiaceae (A/C) ratio is assumed to be a useful index for reconstructing moisture changes in arid and semi-arid regions. Thorough modern pollen studies are still lacking to understand the reliability and limitation of A/C ratio as a moisture indicator, however. Here we review how well this ratio can be applied in arid and semi-arid China on the basis of new surface pollen data, previous data synthesis and other publications. Results indicate that variance in the A/C ratio can permit identification of modern vegetation types and that the A/C ratio generally has a positive relationship with annual precipitation. However, soil salinity, vegetation community composition, human activity and sample provenance (e.g. soil and lake sediments) will affect the values of the A/C ratio in different vegetation zones and therefore the A/C ratio is not comparable in different regions. We argue that the A/C ratio can only be used to reconstruct vegetation types and climate change in regions with precipitation <450–500 mm, and in steppe, steppe desert and desert areas. Careful studies should be undertaken to understand the modern pollen–vegetation–climate relationships in various regions before using the A/C ratio to interpret vegetation and climate.

Cost-effectiveness of two monitoring strategies for the great crested newt (Triturus cristatus)

2010 ◽  
Vol 31 (3) ◽  
pp. 403-410 ◽  
Author(s):  
Jérôme Pellet ◽  
Madeleine Kröpfli ◽  
Patrick Heer
Keyword(s):  
Large Scale ◽  
Cost Effective ◽  
Amphibian Conservation ◽  
Submerged Vegetation ◽  
Vegetation Density ◽  
Triturus Cristatus ◽  
Monitoring Strategies ◽  
Cost Effective Method ◽  
Crested Newt ◽  
Monitoring Protocols

AbstractDesigning cost-effective monitoring protocols is a fundamental prerequisite for amphibian conservation. Here, we report a comparison of flashlight survey and trapping (with and without light sticks as trap baits) in order to determine flashlight detectability and trap detectability of great crested newts (Triturus cristatus). Twelve ponds were surveyed in Switzerland where T. cristatus had been known to occur. We measured covariates affecting both flashlight detectability and trap detectability. Newt flashlight detectability using 20 min long flashlight surveys was on average ± SE = 39% ± 10%). Flashlight detectability was mostly influenced by surface and submerged vegetation density, as well as by water temperature. Newt trap detectability during one night using six funnel traps per pond was on average±SE = 41%±10%. Trap detectability was mainly affected by trap position in the pond, with traps lying on the pond floor being more likely to attract newts. The use of light sticks did not enhance the trap detectability. Estimates of flashlight detectability and trap detectability were used to define how many times the sites have to be visited to be 95% certain of not missing T. cristatus in ponds where they are present. In both cases multiple visits (7 flashlight surveys or 6 trapping sessions) have to be performed. Flashlight surveys are the most easily applied and most cost-effective method to use in large scale programs.

Conservation of Natural Vegetation in Nigeria

1977 ◽  
Vol 4 (3) ◽  
pp. 217-223 ◽  
Author(s):  
Bunyamin A. Ola-Adams ◽  
Dominic E. Iyamabo
Keyword(s):  
Natural Vegetation ◽  
Vegetation Types ◽  
Optimum Size ◽  
Conservation Areas ◽  
Forest Reserves ◽  
Vegetation Zones ◽  
Comprehensive Survey ◽  
Ecological Type ◽  
Representative Samples

The need to conserve representative samples of natural vegetation was recognized in Nigeria over thirty years ago. Before 1950 only two conservation areas had been laid down but at present there are seven in operation. Most of them are between 60 ha (ca 1/4 sq. mile) and 350 ha (ca 12/5 sq. miles) in area, and together they include at least one example of each major ecological type occurring in the country.There are difficulties in constituting and safeguarding conservation areas, particularly outside State Forest Reserves. While it is to be hoped that legislation will soon be introduced to facilitate protection, a comprehensive survey has recently been carried out with a view to substantially increasing the number of conservation areas in Nigeria, and to make them more fully representative of the different vegetation zones of Nigeria.Work is also proceeding towards determining the optimum size for each area within the different vegetation types. It is hoped to be able to establish up to 40 conservation areas within the next 2 years, and ultimately as many as 110 may be designated.

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