نتایج جستجو برای: vegetation density

تعداد نتایج: 453936  

2016
Michael A Irvine James C Bull Matthew J Keeling

Ecological dynamics can produce a variety of striking patterns. On ecological time scales, pattern formation has been hypothesized to be due to the interaction between a species and its local environment. On longer time scales, evolutionary factors must be taken into account. To examine the evolutionary robustness of spatial pattern formation, we construct a spatially explicit model of vegetati...

2017
Ning Wang Juying Jiao Yanfeng Jia Dongli Wang

The Chinese Loess Plateau region has long been suffering from serious soil erosion. Thus, large-scale afforestation has continued during the past decades in order to control soil erosion. Afforestation can dramatically alter nutrient cycles, affect soil-carbon storage, and change hydrology. However, it is unknown how afforestation influences species diversity of the soil seed bank and understor...

Journal: :Remote Sensing 2016
Manuela Domínguez-Beisiegel Carmen Castañeda Bernard Mougenot Juan Herrero

Inland saline wetlands are complex systems undergoing continuous changes in moisture and salinity and are especially vulnerable to human pressures. Remote sensing is helpful to identify vegetation change in semi-arid wetlands and to assess wetland degradation. Remote sensing-based monitoring requires identification of the spectral characteristics of soils and vegetation and their correspondence...

2010
L. Bounoua F. G. Hall P. J. Sellers A. Kumar G. J. Collatz C. J. Tucker M. L. Imhoff

[1] Several climate models indicate that in a 2 × CO2 environment, temperature and precipitation would increase and runoff would increase faster than precipitation. These models, however, did not allow the vegetation to increase its leaf density as a response to the physiological effects of increased CO2 and consequent changes in climate. Other assessments included these interactions but did no...

2013
Yan-Ting Liau Billie Turner Soe Myint Janet Franklin Sergio Rey

i ABSTRACT Two critical limitations for hyperspatial imagery are higher imagery variances and large data sizes. Although object-based analyses with a multi-scale framework for diverse object sizes are the solution, more data sources and large amounts of testing at high costs are required. In this study, I used tree density segmentation as the key element of a three-level hierarchical vegetation...

2014
ERIKA M. DITTMAR

If differences in ecological requirements result in juvenile birds using different habitats from breeding birds, then habitat management to protect those birds must protect both breeding and postbreeding habitats. We examined habitat selection by juvenile black-capped vireos (Vireo atricapilla) following their independence from parental care, in 2010–2013 on Fort Hood Military Reservation in ce...

2004
DRIES BONTE

1. Mobility and emigration were investigated for the wolf spider Pardosa monticola in grey dune fragments from two high-density and one low-density population, where population density was related to patch quality. Pitfall trapping was applied in combination with absolute density estimates by means of quadrat sampling. Orientation behaviour was additionally observed in the highand low-density p...

Journal: :journal of agricultural science and technology 2011
o. esmailzadeh s. m. hosseini m. tabari

we assessed the size and composition of the soil seed bank and above-ground vegetation in 52 relevés representing a range of habitats within an old- growth, temperate deciduous forest at hyrcanian region, northern iran. we identified 63 taxa in the seed bank, with an average density of 4202 seeds/spores per m2 by seedling emergence method. hypericum androsaemum, cardamine impatiens, and rub...

Journal: :مرتع و آبخیزداری 0
شفق رستگار استادیار دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری حسین بارانی دانشیار دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان علی دریجانی استادیار دانشکده اقتصاد کشاورزی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان واحدبردی شیخ دانشیار دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان جمشید قربانی دانشیار دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری محمد قربانی استاد دانشکده اقتصاد کشاورزی، دانشگاه فردوسی مشهد

vegetation cover as the main factor affecting the water erosion plays an important role in preventingsoil loss. to this end, for better understanding the impact of vegetation cover on soil erosion andsediment yield over the major existing geological formations in the summer rangelands of balade inthe mazandaran province, rainfall simulation studies have been carried out using a portable rainfal...

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