scholarly journals Identification of the Optimal Season and Spectral Regions for Shrub Cover Estimation in Grasslands

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3098
Author(s):  
Irini Soubry ◽  
Xulin Guo
Keyword(s):  
Remote Sensing ◽  
Ecosystem Health ◽  
Woody Species ◽  
Shrub Encroachment ◽  
Shrub Cover ◽  
Grassland Ecosystem ◽  
Good Separation ◽  
Spectral Separability ◽  
Late Stages ◽  
Trees And Shrubs

Woody plant encroachment (WPE), the expansion of native and non-native trees and shrubs into grasslands, is a less studied factor that leads to declines in grassland ecosystem health. With the increasing application of remote sensing in grassland monitoring and measuring, it is still difficult to detect WPE at its early stages when its spectral signals are not strong enough. Even at late stages, woody species have strong vegetation characteristics that are commonly categorized as healthy ecosystems. We focus on how shrub encroachment can be detected through remote sensing by looking at the biophysical and spectral properties of the WPE grassland ecosystem, investigating the appropriate season and wavelengths that identify shrub cover, testing the spectral separability of different shrub cover groups and by revealing the lowest shrub cover that can be detected by remote sensing. Biophysical results indicate spring as the best season to distinguish shrubs in our study area. The earliest shrub encroachment can be identified most likely only when the cover reaches between 10% and 25%. A correlation between wavelength spectra and shrub cover indicated four regions that are statistically significant, which differ by season. Furthermore, spectral separability of shrubs increases with their cover; however, good separation is only possible for pure shrub pixels. From the five separability metrics used, Transformed divergence and Jeffries-Matusita distance have better interpretations. The spectral regions for pure shrub pixel separation are slightly different from those derived by correlation and can be explained by the influences from land cover mixtures along our study transect.

scholarly journals Seasonal Spectral Separation of Western Snowberry and Wolfwillow in Grasslands with Field Spectroradiometer and Simulated Multispectral Bands

Environments ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 60
Author(s):  
Irini Soubry ◽  
Xulin Guo
Keyword(s):  
Cross Validation ◽  
Woody Plant ◽  
Woody Species ◽  
Woody Plant Encroachment ◽  
Canadian Prairies ◽  
Fall Season ◽  
Spectral Separation ◽  
Significant Difference ◽  
Spectral Separability ◽  
Trees And Shrubs

Woody plant encroachment (WPE), the expansion of native and non-native trees and shrubs into grasslands, has led to degradation worldwide. In the Canadian prairies, western snowberry and wolfwillow shrubs are common encroachers, whose cover is currently unknown. As the use of remote sensing in grassland monitoring increases, opportunities to detect and map these woody species are enhanced. Therefore, the purpose of this study is to identify the optimal season for detection of the two shrubs, to determine the sensitive wavelengths and bands that allow for their separation, and to investigate differences in separability potential between a hyperspectral and broadband multispectral approach. We do this by using spring, summer, and fall field-based spectra of both shrubs for the calculation of spectral separability metrics and for the simulation of broadband spectra. Our results show that the summer offers higher discrimination between the two species, especially when using the red and blue spectral regions and to a lesser extent the green region. The fall season fails to provide significant spectral separation along the wavelength spectrum. Moreover, there is no significant difference in the results from the hyperspectral or broadband approach. Nevertheless, cross-validation with satellite imagery is needed to confirm the current results.

Shrub encroachment is not always land degradation: Insights from ground-dwelling beetle species niches along a shrub cover gradient in a semi-arid Namibian savanna

2018 ◽  
Vol 30 (1) ◽  
pp. 14-24 ◽  
Author(s):  
Robert Hering ◽  
Morgan Hauptfleisch ◽  
Katja Geißler ◽  
Arnim Marquart ◽  
Maria Schoenen ◽  
...  
Keyword(s):  
Land Degradation ◽  
Shrub Encroachment ◽  
Beetle Species ◽  
Shrub Cover ◽  
Semi Arid

scholarly journals Use of waste material in cultivation substrates

2004 ◽  
Vol 52 (2) ◽  
pp. 43-52
Author(s):  
Petr Salaš
Keyword(s):  
Large Scale ◽  
Woody Species ◽  
Practical Experience ◽  
Biological Properties ◽  
Waste Material ◽  
Research Activities ◽  
Cultivation Technology ◽  
Mutual Relations ◽  
Trees And Shrubs ◽  
Special Soil

Gardeners' practical experience and experimental work prove the affirmation that the used substrate is a very important base for the production of quality nursery products. It is important to emphasis the complexity and synergy of all factors influencing the ecosystem and there mutual relations. Physical, chemical and biological properties do not separately affect the growth and development of plants. In addition, the relations are not statical but differ in relation with other factors changes. This article is dealing with the possibility to use waste material from timber processing in cultivation substrates. The large scale use of such substrates would enable people to reach a relative independence from peat substrates, of which the global reserve is gradually decreasing.Our research activities focus on the use of bark. The basic problems of a bark substrate are easy dehydration and unbalanced nutrition of trees and shrubs. The suggested and experimented cultivation technology solves these problems. It is based on the cultivation of woody species in bark substrates, using modern irrigation systems, slow release fertilisers (Silvamix Forte) and special soil conditioners (TerraCottem). This technology was tested on the following species of trees and shrubs:MalusandBuxus.

scholarly journals Ecosystem Health Assessment of World Natural Heritage Sites Based on Remote Sensing and Field Sampling Verification: Bayanbulak as Case Study

2020 ◽  
Vol 12 (7) ◽  
pp. 2610
Author(s):  
Zhi Wang ◽  
Zhaoping Yang ◽  
Hui Shi ◽  
Fang Han ◽  
Qin Liu ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Ecosystem Health ◽  
Buffer Zone ◽  
Ecological Monitoring ◽  
Scientific Basis ◽  
Field Sampling ◽  
Natural Heritage ◽  
Heritage Sites ◽  
World Natural Heritage ◽  
Over Time

Monitoring the ecosystem health for world natural heritage sites is essential for protecting them and benefits the formulation of more targeted protection policies. This study used Bayanbulak world natural heritage site as a case, established a framework for assessing the ecosystem health through remote sensing based on the parameters of ecosystem vigour, organization, resilience, and services. Then, we verified the obtained results through field sampling. The results show that the ecosystem health in the overall study area had declined over time, however, the health within the property zone remained at high levels and stable. The area proportion of low health was low and primarily distributed in the buffer zone. Thus, in general, the ecosystem in the study area was healthy. Besides, the ecosystem health exhibited distinct spatial agglomeration characteristics, and the degree of agglomeration enhanced over time. In addition, the field vegetation samplings were consistent with the changes in the ecosystem health levels, therefore, the result of RS monitoring of ecosystem health were credible. Thus, this study provides a scientific basis for heritage managers to formulate suitable ecological protection policies and should aid further research on the ecological monitoring of heritage sites.

scholarly journals Agroforestry for ruminants: a review of trees and shrubs as fodder in silvopastoral temperate and tropical production systems

2018 ◽  
Vol 58 (5) ◽  
pp. 767 ◽  
Author(s):  
Sophie Vandermeulen ◽  
Carlos Alberto Ramírez-Restrepo ◽  
Yves Beckers ◽  
Hugues Claessens ◽  
Jérôme Bindelle
Keyword(s):  
Production Systems ◽  
Woody Species ◽  
Agroforestry Systems ◽  
Past Century ◽  
Environment Friendly ◽  
Airborne Pollutants ◽  
Positive Effects ◽  
Trees And Shrubs ◽  
Salix Spp ◽  
Feeding Systems

Among the oldest agroforestry systems, silvopastoralism uses shrubs and trees to feed ruminants. The practice is common in extensive livestock production systems, whereas the intensification of grass-based systems in the past century has led to the removal of woody species from agricultural temperate landscapes. In Europe however, woody species are promoted again on grasslands through environment-friendly policies due to the ecosystem services they provide such as carbon sequestration, control of soil erosion, limitation of airborne pollutants and biodiversity conservation. Positive effects of browse on rumen digestion and parasite control have also been documented across different plant species and regions. Under optimal conditions, feeding ruminants from woody fodder sustains animal production. Nonetheless, limitations can restrict the use of woody forage into animal diets, such as the presence of anti-nutritive and toxic compounds. The incorporation of this resource in ruminant feeding systems raises the question of the management of the interface between the plant and the animal. Various management systems are practiced. Temperate species such as Salix spp. and Populus spp. are fed to sheep and cattle in fodder blocks or by pruning trees in New Zealand, and Fraxinus spp. or Corylus avellana in hedgerows supply forage to livestock in Belgium, whereas Leucaena leucocepahala and Desmanthus spp. browsing is common in Australia. Nowadays, ensiling and pelleting techniques are being developed as a way to store browse forage. As the renewed interest in using shrubs and trees to feed ruminants is recent, especially in temperate regions, additional research about the optimal introduction of this resource within systems is needed.

Sign in / Sign up

Export Citation Format

Share Document