نتایج جستجو برای: shrub canopy

تعداد نتایج: 19636  

2017
John E. Hobbie Gaius R. Shaver Edward B. Rastetter Jessica E. Cherry Scott J. Goetz Kevin C. Guay William A. Gould George W. Kling

Long-term measurements of ecological effects of warming are often not statistically significant because of annual variability or signal noise. These are reduced in indicators that filter or reduce the noise around the signal and allow effects of climate warming to emerge. In this way, certain indicators act as medium pass filters integrating the signal over years-to-decades. In the Alaskan Arct...

2016
Curtis M. Chance Nicholas C. Coops Andrew A. Plowright Thoreau R. Tooke Andreas Christen Neal Aven

Proactive management of invasive species in urban areas is critical to restricting their overall distribution. The objective of this work is to determine whether advanced remote sensing technologies can help to detect invasions effectively and efficiently in complex urban ecosystems such as parks. In Surrey, BC, Canada, Himalayan blackberry (Rubus armeniacus) and English ivy (Hedera helix) are ...

Journal: :Remote Sensing 2017
Ning Liu Richard J. Harper Rebecca N. Handcock Bradley Evans Stanley J. Sochacki Bernard Dell Lewis L. Walden Shirong Liu

Dryland salinity is a major land management issue globally, and results in the abandonment of farmland. Revegetation with halophytic shrub species such as Atriplex nummularia for carbon mitigation may be a viable option but to generate carbon credits ongoing monitoring and verification is required. This study investigated the utility of high-resolution airborne images (Digital Multi Spectral Im...

2002
A. Huete K. Didan T. Miura E. P. Rodriguez X. Gao L. G. Ferreira

We evaluated the initial 12 months of vegetation index product availability from the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the Earth Observing System-Terra platform. Two MODIS vegetation indices (VI), the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI), are produced at 1-km and 500-m resolutions and 16-day compositing periods. This pape...

2015
Robert D Hollister Jeremy L May Kelseyann S Kremers Craig E Tweedie Steven F Oberbauer Jennifer A Liebig Timothy F Botting Robert T Barrett Jessica L Gregory

Few studies have clearly linked long-term monitoring with in situ experiments to clarify potential drivers of observed change at a given site. This is especially necessary when findings from a site are applied to a much broader geographic area. Here, we document vegetation change at Barrow and Atqasuk, Alaska, occurring naturally and due to experimental warming over nearly two decades. An exami...

2001
José M. Gómez José A. Hódar Regino Zamora Jorge Castro Daniel García

The spatial structure of plant communities as well as the quality and abundance of neighbours can strongly influence the intensity of herbivory suffered by a plant. In this paper, we study the effect of the association with shrubs on the ungulate herbivory suffered by Scots pine (Pinus sylvestris var. nevadensis Christ., Pinaceae) saplings in two isolated, fragmented populations in southeastern...

2012
M. P. McClaran

Regression equations were developed to estimate above ground biomass and carbon and nitrogen mass of foliage and stem size fractions from plant size dimensions (basal diameter, canopy area, height, canopy volume) for a tall shrub species (Prosopis velutina) that has increased in abundance in arid and semi-arid grasslands in the southwestern United States and northwestern Mexico. Regression equa...

2016
Sandra Knapp Maria S. Vorontsova

The African Non-Spiny (ANS) clade contains 14 species of mostly large canopy lianas or scandent shrubs confined to Madagascar (10) and continental Africa (4, with with one species reaching the southern Arabian peninsula). Members of the clade were previously classified in sections Afrosolanum Bitter, Benderianum Bitter, Lemurisolanum Bitter, Macronesiotes Bitter and Quadrangulare Bitter, and we...

2001
G. Wohlfahrt M. Bahn U. Tappeiner

A model is presented which allows simulation of vegetation–atmosphere CO2 and energy exchange of multi-component, multi-species canopies, explicitly taking into account the structural and functional properties of the various components and species. The model is parameterised for a meadow and an abandoned area at the ECOMONT study area Monte Bondone (1500 m a.s.l., Trento/Italy). A series of sen...

2007
R. A. Zahawi C. K. Augspurger

We compared early plant succession in four abandoned pastures of differing age since abandonment and a nearby secondary forest site in northwestern Ecuador. Two "Open" pastures had no tree canopy covering, and two "Guava" pastures had a well-developed canopy cover of Psidium guajaua. No site had been seeded with pasture grasses. All pastures were compared in a chronological sequence; nvo were m...

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