نتایج جستجو برای: percent vegetation cover

تعداد نتایج: 243442  

2008
O. Durán

In this work we present measurements of vegetation cover over parabolic dunes with different degree of activation along the north-eastern Brazilian coast. We are able to extend the local values of the vegetation cover density to the whole dune by correlating measurements with the gray-scale levels of a high resolution satellite image of the dune field. The empirical vegetation distribution is f...

The study of  vegetation dynamics under grazed and non-grazed rangelands is one of the most important prerequisites for range improvement. In this research, vegetation composition and the vegetation functional groups were compared in an exclosure site (livestock excluded for six years) and grazed area in semi-steppe rangelands in Tehran province. Systematic random sampling technique through the...

Journal: :international journal of advanced biological and biomedical research 2013
sahar delpasand maryam moradnezhadi zahra hossaini yousef askari

the preparation of vegetation cover maps by used the land inventory and a traditional method has a lot of cost and time. but today, remote sensing is one of the main sources of data collection and information production for study and monitoring land resources, and was efficient tools for providing quickly and timely data and information needs for program planning in the natural resource filed. ...

Journal: :Ecology 2008
Ron E VanNimwegen Justin Kretzer Jack F Cully

As ecosystem engineers, prairie dogs (Cynomys spp.) physically alter their environment, but the mechanism by which these alterations affect associated faunal composition is not well known. We examined how rodent and vegetation communities responded to prairie dog colonies and landcover at the Cimarron National Grassland in southwest Kansas, USA. We trapped rodents and measured vegetation struct...

2005
Susumu OKITSU S. OKITSU

Here, I describe the geographical distribution of the savanna types in Namibia and identify the factors controlling the occurrence of each savanna type in relation to the amount of annual precipitation and the various physiographical regions, including the mopane ( Colophospermum mopane) area. The different types of savanna can be distinguished on the basis of the leaf habits of the dominant ve...

2007
HANH M. NGUYEN

Ecological indicators are needed to evaluate natural biodiversity and to estimate environmental change. I used bird community composition as an environmental indicator to evaluate forest disturbance (at the community level) in areas of Western Mexico. Surveyed bird and vegetation composition data at 79 sites within regions of the Sierra Madre del Sur and Transvolcanic Belt Provinces of Central ...

ژورنال: علوم آب و خاک 2018

This research was aimed to simulate and prioritize the effective factors on water erosion using USLE-M in the system dynamic model. In this integrated model, by using the system dynamic simulation software (Vensim), all variables and factors involved in erosion and soil loss were considered according to the USLE-M model. After model implementation, the estimated values and observations were com...

Jamshid Khatir Namany Morteza Akbarzadeh, Seyyed Ali Hosseini

Studies on vegetation changes of rangelands under grazed and non-grazedconditions are of great importance in the range management planning programs. To determinethe change process of vegetation, this study was performed in Inche Shorezar site of Golestanprovince for nine years (1997-2005). The vegetation parameters were measured every year inseveral fixed plots inside and adjacent of exclosures...

1999
Joanna McKenzie

A case-control study of 132 possum capture sites was used to identify habitat factors associated with the probability of capturing TB possums. Two unconditional logistic regression models were produced. Slope of the land and factors associated with the quality of dens were associated with the probability of capturing multiple TB possums. Slope of the land, height of trees, percent cover of vege...

Journal: :Environmental management 2006
Steven S Seefeldt D Terrance Booth

Methods that are more cost-effective and objective are needed to detect important vegetation change within acceptable error rates. The objective of this research was to compare visual estimation to three new methods for determining vegetation cover in the sagebrush steppe. Fourteen management units at the US Sheep Experiment Station were identified for study. In each unit, 20 data collection po...

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