نتایج جستجو برای: lack of vegetation

تعداد نتایج: 21169415  

Knowledge of rangeland vegetation characteristics as well as factors affecting it in environmental planning, land management and sustainable development is very important. However, regional and up-to-date maps of pasture vegetation cover are not always available. In this study, in order to plot the vegetation cover percentage of the rangelands and monitor its changes in drought and wet periods,...

Journal: :international journal of environmental research 2012
j.o. odindi p. mhangara

given the critical role played by urban green spaces and the emergence of remote sensing as avaluable natural resource management tool, this study sought to identify trends in green spaces within thecontext of south africa’s transition period (1990 - 2000). using the city of port elizabeth as a case study, threesets of landsat - 5 thematic mapper images (1990, 1995 and 2000) were geo-processed,...

Journal: :journal of rangeland science 2014
seyyed morteza abtahi amr ali shahmoradi ehsan zandi esfahan

abstract. the purpose of this study was to investigate vegetation dynamics and range conditions considering the climatic conditions and soil properties in haftooman, khoor and biabanak deserts, iran. for this purpose, after determining vegetation types and the associated species, the type of rangeland utilization, grazing season, the livestock type, the other relevant information, vegetation da...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2011
Juan Carlos Laso Bayas Carsten Marohn Gerd Dercon Sonya Dewi Hans Peter Piepho Laxman Joshi Meine van Noordwijk Georg Cadisch

In a tsunami event human casualties and infrastructure damage are determined predominantly by seaquake intensity and offshore properties. On land, wave energy is attenuated by gravitation (elevation) and friction (land cover). Tree belts have been promoted as "bioshields" against wave impact. However, given the lack of quantitative evidence of their performance in such extreme events, tree belt...

Journal: :Remote Sensing 2017
Xuelian Meng Nan Shang Xukai Zhang Chunyan Li Kaiguang Zhao Xiaomin Qiu Eddie Weeks

Photogrammetric UAV sees a surge in use for high-resolution mapping, but its use to map terrain under dense vegetation cover remains challenging due to a lack of exposed ground surfaces. This paper presents a novel object-oriented classification ensemble algorithm to leverage height, texture and contextual information of UAV data to improve landscape classification and terrain estimation. Its i...

Journal: :Ecological applications : a publication of the Ecological Society of America 2015
Michael D Craig Vicki L Stokes Joseph B Fontaine Giles E StJ Hardy Andrew H Grigg Richard J Hobbs

State-and-transition models are increasingly used as a tool to inform management of post-disturbance succession and effective conservation of biodiversity in production landscapes. However, if they are to do this effectively, they need to represent faunal, as well as vegetation, succession. We assessed the congruence between vegetation and avian succession by sampling avian communities in each ...

2013
Fredrik Huthoff Menno W. Straatsma Denie C. M. Augustijn Suzanne J. M. H. Hulscher

A simple idealized model to describe the hydraulic resistance caused by vegetation is compared to results from flow experiments conducted in natural waterways. Two field case studies are considered: fixed-point flow measurements in a Green River (case 1) and vessel-borne flow measurements along a cross-section with floodplains in the river Rhine (case 2). Analysis of the two cases shows that th...

2016
Carmelo Alonso Ana M. Tarquis Ignacio Zúñiga Rosa M. Benito

Although the authors’ similarity report found some similarity with other papers by the authors, my main concern was a lack of similarity with one of them! Indeed, the authors completely failed to cite the first and still the most comprehensive multifractal analysis of satellite derived vegetation indices. Without this, their own paper is without adequate context, their results are simply isolat...

2015
Uyen Nguyen Edward P. Glenn Pamela L. Nagler Russell L. Scott

The Upper San Pedro River is one of the few remaining undammed rivers that maintain a vibrant riparian ecosystem in the southwest United States. However, its riparian forest is threatened by diminishing groundwater and surface water inputs, due to either changes in watershed characteristics such as changes in riparian and upland vegetation, or human activities such as regional groundwater pumpi...

Journal: :international journal of agricultural management and development 2015
ali mohammadi torkashvand shahryar sobhe zahedi

an important factor in sustainable agriculture and economic management is to calculate areas under different crops that the inputs of agriculture connect to this topic. planning of agricultural mechanization, fertilizer and pesticide requirements, pests and diseases control, estimates of agricultural production, income and tax and financial planning, all linked to the cultivated areas and estim...

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