نتایج جستجو برای: vegetation

تعداد نتایج: 47633  

2015
Gabriella Balacco Benedetto Figorito Eufemia Tarantino Andrea Gioia Vito Iacobellis

The vegetation space-time variability during 1999-2010 in the North of the Apulian region (Southern Italy) was analysed using SPOT VEGETATION (VGT) sensor data. Three bands of VEGETATION (RED, NIR and SWIR) were used to implement the vegetation index named reduced simple ratio (RSR) to derive leaf area index (LAI). The monthly average LAI is an indicator of biomass and canopy cover, while the d...

Journal: :Demographic research 2012
Raphael J Nawrotzki Lori M Hunter Thomas W Dickinson

BACKGROUND Although natural resources play a central role in rural livelihoods across the globe, little research has explored the relationship between migration and natural capital use, particularly in combination with other livelihood capitals (i.e., human, social, financial and physical). OBJECTIVE Grounded in the rural livelihood framework, this paper explores the association between the l...

Journal: :Remote Sensing 2016
Hasan Jackson Stephen D. Prince

Land degradation in drylands is the process in which undesirable conditions emerge due to human and natural causes. Despite the particularly deleterious effects of degradation, and it’s potentially irreversible nature, regional assessments have provided conflicting extents, rates, and severities of degradation, both globally and regionally. Current monitoring of degradation relies upon the dete...

2016
Borja Jiménez‐Alfaro Milan Chytrý Ladislav Mucina James B. Grace Marcel Rejmánek

Broad-scale animal diversity patterns have been traditionally explained by hypotheses focused on climate-energy and habitat heterogeneity, without considering the direct influence of vegetation structure and composition. However, integrating these factors when considering plant-animal correlates still poses a major challenge because plant communities are controlled by abiotic factors that may, ...

Journal: :Journal of nematology 1995
S P Huang J H Cares

Communities of plant-parasitic nematodes collected from five different vegetation types (canopy woodland, savannah, gallery forest, cultivated perennial, and annual plants) and soils (yellowish red latosols, dark red latosols, arenosols, acrisols, and gleysols) were studied. Ninety percent of the soil samples collected from savannah contained at least four genera of plant-parasitic nematodes. T...

2003
E. Jeppesen

The turbidity of lakes is generally considered to be a smooth function of their nutrient status. However, recent results suggest that over a range of nutrient concentrations, shallow l&es can have two alternative equilibria: a clear state dominated by nquatic vegetation, and a turbid state characterized by high algal biomass. This bi-stability has important implications for the possibilities of...

2000
Christopher D. Clegg Karl Ritz Bryan S. Griffiths

Total DNA was directly extracted from microbial populations in grassland soils taken from three geographically distinct upland sites at Garrigill, Aber and Sourhope, UK. Within each site, grasslands were categorised using the National Vegetation Classification into distinct vegetation sequences, namely unimproved, semi-improved and improved. Microbial community DNA was extracted from the differ...

Journal: :Global change biology 2015
John Harte Scott R Saleska Charlotte Levy

Ecosystem responses to climate change can exert positive or negative feedbacks on climate, mediated in part by slow-moving factors such as shifts in vegetation community composition. Long-term experimental manipulations can be used to examine such ecosystem responses, but they also present another opportunity: inferring the extent to which contemporary climate change is responsible for slow cha...

2014
Chun-Huo Chiu Anne Chao

In this Appendix, we summarize some basic properties of the three classes of functional diversity measures: (1) functional Hill number ) (Q D q which quantifies the effective number of equally abundant and equally distinct species in an assemblage with a constant species pairwise distance Q, where Q denotes Rao’s quadratic entropy; (2) mean functional diversity MD(Q) = Q Q D q × )] ( [ which qu...

2013
Laia Núñez-Casillas José Rafael García Lázaro José Andrés Moreno-Ruiz Manuel Arbelo

The turn of the new millennium was accompanied by a particularly diverse group of burned area datasets from different sensors in the Canadian boreal forests, brought together in a year of low global fire activity. This paper provides an assessment of spatial and temporal accuracy, by means of a fire-by-fire comparison of the following: two burned area datasets obtained from SPOT-VEGETATION (VGT...

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