oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
The role of foraging (harvester) ants, Messor cephalotes, in land degradation in Meserani area Monduli District, Tanzania
RB Kiunsi
Ethiopian Journal of Environmental Studies and Management , 2010,
Abstract: Meserani is a semi arid area in Monduli District in north east Tanzania that is prone to land degradation in terms of vegetation and soil degradation due to natural and anthropological factors. For a number of years the local community including extension officers had suspected that in certain locations of Meserani area bare lands, apart from grazing and farming activities were also created by grazing insects. The main objective of this paper was firstly, to identify the type of grazing insects that were creating bare lands, hence land degradation. Land degradation in this context is taken to mean the removal of herbaceous vegetation caver. Secondly, to determine the extent in which grazing insects are contributing to land degradation in the area. The harvester ants of species Messor cephalotes, Emmery were identified as the main insects that were foraging herbaceous vegetation cover thus creating bare lands in some of the locations in the study area. Areas with high intensity of human activities in terms of framing and grazing had more bare lands created by ants than the fallow or stony areas. Therefore in the Meserani harvester ants just like grazing or farming activities were contributing to land degradation through the creation of bare lands.
Land Cover Change and its Causes in Yulin Distr ict
陕北榆林地区土地覆被变化分析

LI Zhongfeng,CAI Yunlong,
李忠峰
,蔡运龙

地理科学进展 , 2006,
Abstract: Yulin district is located in the most Northern part of Shaanxi province, between 36°57′and 39°34′N, and 107°28′and 111°15′E. Yulin district is one of the areas of the most serious soil erosion in the world and receives a lot of attention from the Chinese government and international societies. After the establishment of the People's Republic of China, the desertification intensity declined because of rehabilitation measures. However, there is lack of knowledge concerning the dynamics of land cover and the complex role of factors in inducing changes in land cover. In the study, by usage of normalized difference vegetation index(NDVI) as an indicator of vegetation activity, seasonal trends of vegetation activity and their dynamic responses to climate changes in Yulin district were explored based on remotely sensed data (NOAA- AVHRR and VEGETATION) from 1981 to 2004. As a result, spatially averaged seasonal NDVI in Yulin showed a pronounced increase during the last two decades. The average autumn NDVI indicated the most significant increase. By analyzing inter- annual changes in seasonal NDVI, it was found that the advance of growing season was a major way for response of vegetation activity to climate changes and that the way exhibited a large regional heterogeneity. From the southeast to the northwest, change amplitude showed a declining trend.
The Effects of Irrigation on Land Degradation by Land Division  [PDF]
Mesut Akgul,Taskin Oztas,Yusuf Ucar
Journal of Biological Sciences , 2005,
Abstract: This study was carried out to determine the effects of irrigation on the land degradation by land division in cultivated lands of Yenisarbademli district, Isparta-Turkey. In the study, some maps of lands and the database which created in another study were used mostly and data were evaluated using the electronic computing tables and some computer programs. Results indicated that total of 8308.7 da cultivated lands consisted of 7251 parcels of which 58.3% had a size smaller than 1.0 da. An average size of these parcels is 1.15 da. Lands were separated into five irrigation groups based on irrigation case and length of irrigated period. There were significant differences in average parcel sizes among the groups (p<0.01). Although, the average parcel sizes of the lands which have been irrigated over 30 years were in the same group, they were in different groups for the lands which have been irrigated for seven years or not under irrigation at all. It was concluded that the degree of land division increased by increment in irrigated period and affected by soil properties related to irrigation.
Analysis of the land landscape changes and its driving mechanism in vulnerable ecological area: a case study of Yulin city
生态脆弱区土地利用格局变化及其驱动机制分析 ——以陕西榆林市为例

GUO Li-ying,LIU Yan-sui,GUO Li-ying,REN Zhi-yuan,
郭丽英
,刘彦随,郭丽英,任志远

资源科学 , 2005,
Abstract: In this study we quantified land landscape change in the vulnerable ecological area of Yulin city between 1985 and 2000 using remote sensing and GIS in conjunction with landscape modeling. It was found that fallow land decreased by 125,147 hm2 while grassland and woodland increased by 107,975 and 17,157 hm2, respectively. The three most prominent changes were from fallow land to grassland at 129,926 hm2, and degradation of grassland from a higher cover density to a lower one at 16,996 hm2 , and from grassland to woodland at 15,651 hm2. The major factors responsible for these changes are identified as the change in the government policy on preserving the environment, continued growth in mining, and urbanization. It is concluded that as arid Yulin city has a highly vulnerable landscape that is sensitive to fluctuations in the natural environment and to changes in government land use policy. The efforts in restoring the deteriorated ecosystem have reaped certain benefits in reducing the spatial extent of sandy land through replacement by non-irrigated farmland, woodland and grassland. On the other hand, continued growth in mining and urbanization has exerted adverse impacts on the land landscape. At present regional economic development is in direct conflict with the protection of the natural environment. Such a conflict has caused the destruction to the land resources and fragmentation of the landscape accompanied by land desertification, even seriously in some localities.
The Land Use Change and Its Eco-environmental Effects in Transitional Agro-pastoral Region--A Case Study of Yulin City in Northern Shaanxi Province
北方农牧交错带土地利用变化及其生态环境效应--以陕北榆林市为例

YANG Shuhe,YAN Haili,GUO Liying,
杨述河
,闫海利,郭丽英

地理科学进展 , 2004,
Abstract: Based on the data of land use/land cover of Yulin in northern Shaanxi, the process of land use change and its eco-environmental effects were quantified and analyzed, the results indicate: the land use pattern had a large change in the last 15 years. Farmland decreased by 405.98 hm2, and forestland and grassland increased by 17 157.02 hm2 and 107 975.17 hm2. The transitional quantities of no use land to grassland are the largest, and the following is degradation of grassland. The general quality of regional eco-environment has improved in the last 15 years. However, the trends of both improvement and degradation in eco-environment were coexist, and displayed their spatial heterogeneity in county-level. The land use change in Yulin has obvious regional difference, and in north wind-sand area the change is more serious and the process of land use change is more active. The spatial rule of eco-environmental effect caused by land use change presents: wind-sand area in north has a better improvement in eco-environment than that of hilly-donga in south. The main factors causing eco-environment change of improvement and degradation are transition of forest and grassland, and tree planting and forestation have the most distribution to the improvement of eco-environment, with its distribution ratio 74.8%.
Types of Land Degradation in Bhutan
Chencho Norbu et al
Journal of Bhutan Studies , 2003,
Abstract: There is a growing global awareness that land degradation isas much a threat to environmental well–being as moreobvious forms of damage, such as air and water pollution (e.g.Greenland & Szalbocs, 1994; Conacher, 2001). Although thesource of land degradation is usually local, its effects oftenstretch for considerable distances from the source site. It canimpact large areas and many people. Governments, NGO’sand community groups therefore have the right and duty tobe concerned, and to intervene and assist where needed.Because of its topography and altitude, Bhutan hasinherently limited resources of productive land. Moreover,the predominantly steep slopes put these resources atparticular risk from some forms of degradation. Landdegradation is therefore an even more serious threat inBhutan than in most places. This is recognised in policy,vision, and review documents, such as the Biodiversity ActionPlan (MOA, 1998), the National Environment Strategy (NEC,1998), and Bhutan 2020.
The causes of land landscape changes in semi-arid area of Northwest China: a case study of Yulin city

GUO Liying,REN Zhiyuan,LIU Yansui,

地理学报 , 2006,
Abstract: Rapid land landscape change has taken place in many arid and semi-arid regions such as the vulnerable ecological area over the last decade. In this paper, we quantified land landscape change of Yulin in this area between 1985 and 2000 using remote sensing and GIS. It was found that fallow landscape decreased by 125,148 hm2 while grassland and woodland increased by 107,975 hm2 and 17,157 hm2, respectively. The major factors responsible for these changes are identified as the change in the government policy on preserving the environment, continued growth in mining, and urbanization. The efforts in restoring the deteriorated ecosystem have reaped certain benefits in reducing the spatial extent of sandy land through replacement by non-irrigated farmland, woodland and grassland. On the other hand, continued expansion of mining industry and urbanization has exerted adverse impacts on the land landscape. At present regional economic development conflicts directly with the protection of the natural environment. Such a conflict has caused the destruction to the land resources and fragmentation of the landscape accompanied by land desertification, the case is even serious in some localities.
WATER DEGRADATION OF BIRBHUM DISTRICT  [PDF]
GOPAL CHANDRA DEBNATH,PROLAY MONDAL
Golden Research Thoughts , 2013, DOI: 10.9780/22315063
Abstract: Water is the primary medium through which climate change impacts the earth's ecosystem and people. Climate change is the fundamental driver of change in the world's water resources and adds additional stress through its effects on other externalities. The UN suggests that each person needs 20-50 liters of water a day to ensure their basic needs for drinking, cooking and cleaning. The world uses fresh water about 70 percent for irrigation, about 22 percent for industry and about 8 percent for domestic use. Another general perception of water quality is that of a simple property that tells whether water is polluted or not. In fact, water quality is a complex subject, in part because water is a complex medium intrinsically tied to the ecology of the Earth. Industrial and commercial activities (e.g. manufacturing, mining, construction, transport) are a major cause of water pollution as are runoff from agricultural areas, urban runoff and discharge of treated and untreated sewage.The quality of drinking-water is a powerful environmental determinant of health. Assurance of drinking-water safety is a foundation for the prevention and control of waterborne diseases. We have attempt to this study for what are the causes of water degradation and what is its integrated management? Here we found uneven pressure of human beings on Land, the water degradation take place.
The Integrated Assessment of Land Degradation  [cached]
Luca Salvati,Maria Elisa Venezian Scarascia,Marco Zitti,Agostino Ferrara
Italian Journal of Agronomy , 2009, DOI: 10.4081/ija.2009.3.77
Abstract: This paper reviews recent findings on the complex field of land degradation (LD) with focus on the Mediterranean Basin and Italy, in particular. The LD definition and assessment methods are examined in the light of the most important natural and human driving forces of the phenomenon, such as land use and climate changes.Various methodological issues are dealt with from multidisciplinary perspective with the aim of providing the ground for the development of integrated approaches: monitoring needs, assessment of costs, development of mitigation strategies, etc. Factors affecting land vulnerability to degradation are classified into bio-physical and socio-economic drivers with some examples of applications in Italy. The role of determinants such as agricultural development, population growth, and urban sprawl is recognised as important but still ambiguous and thus needs further studies. Based on these findings, policy responses aimed at mitigating LD and thus reducing desertification risk are discussed and methodological proposal are presented.
The Integrated Assessment of Land Degradation  [cached]
Luca Salvati,Maria Elisa Venezian Scarascia,Marco Zitti,Agostino Ferrara
Italian Journal of Agronomy , 2011, DOI: 10.4081/ija.2009.3.77
Abstract: This paper reviews recent findings on the complex field of land degradation (LD) with focus on the Mediterranean Basin and Italy, in particular. The LD definition and assessment methods are examined in the light of the most important natural and human driving forces of the phenomenon, such as land use and climate changes.Various methodological issues are dealt with from multidisciplinary perspective with the aim of providing the ground for the development of integrated approaches: monitoring needs, assessment of costs, development of mitigation strategies, etc. Factors affecting land vulnerability to degradation are classified into bio-physical and socio-economic drivers with some examples of applications in Italy. The role of determinants such as agricultural development, population growth, and urban sprawl is recognised as important but still ambiguous and thus needs further studies. Based on these findings, policy responses aimed at mitigating LD and thus reducing desertification risk are discussed and methodological proposal are presented.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.