نتایج جستجو برای: vegetation dynamic

تعداد نتایج: 451846  

2017
Kelly Elschot Anke Vermeulen Wouter Vandenbruwaene Jan P. Bakker Tjeerd J. Bouma Julia Stahl Henk Castelijns Stijn Temmerman

The relative impact of top-down control by herbivores and bottom-up control by environmental conditions on vegetation is a subject of debate in ecology. In this study, we hypothesize that top-down control by goose foraging and bottom-up control by sediment accretion on vegetation composition within an ecosystem can co-occur but operate at different spatial and temporal scales. We used a highly ...

Journal: :Philosophical transactions of the Royal Society of London. Series B, Biological sciences 2016
Kevin T Uno Pratigya J Polissar Emma Kahle Craig Feibel Sonia Harmand Hélène Roche Peter B deMenocal

Reconstructing vegetation at hominin fossil sites provides us critical information about hominin palaeoenvironments and the potential role of climate in their evolution. Here we reconstruct vegetation from carbon isotopes of plant wax biomarkers in sediments of the Nachukui Formation in the Turkana Basin. Plant wax biomarkers were extracted from samples from a wide range of lithologies that inc...

G. A. Heshmati V. R. Squires

Rangeland ecosystems shift across dynamic thresholds between differentecological states in response to natural or human-induced factors. These differentecological states are the result of interactions among climate, soils, grazing history,and management practices. The notion of a single ‘‘pristine’’ final state is onlyconceptual in nature, and because of this, dynamic thresholds and the effects...

Journal: :Natural Hazards and Earth System Sciences 2022

Abstract. Agricultural drought, which occurs due to a significant reduction in the moisture required for vegetation growth, is most complex amongst all drought categories. The onset of agriculture slow and can occur over vast areas with varying spatial effects, differing particular land cover or specific agro-ecological sub-regions. These variations imply that monitoring forecasting agricultura...

2003
Dominique Bachelet Ronald P. Neilson Thomas Hickler Raymond J. Drapek James M. Lenihan Martin T. Sykes Benjamin Smith Stephen Sitch Kirsten Thonicke

[1] Simulations of potential vegetation distribution, natural fire frequency, carbon pools, and fluxes are presented for two DGVMs (Dynamic Global Vegetation Models) from the second phase of the Vegetation/Ecosystem Modeling and Analysis Project. Results link vegetation dynamics to biogeochemical cycling for the conterminous United States. Two climate change scenarios were used: a moderately wa...

2016
Marike Trytsman Robert H. Westfall Philippus J. J. Breytenbach Frikkie J. Calitz Abraham E. van Wyk

The principal aim of this study was to establish biogeographical patterns in the legume flora of southern Africa so as to facilitate the selection of species with agricultural potential. Plant collection data from the National Herbarium, South Africa, were analysed to establish the diversity and areas covered by legumes (Leguminosae/Fabaceae) indigenous to South Africa, Lesotho and Swaziland. A...

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...

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