نتایج جستجو برای: plant canopy cover

تعداد نتایج: 506160  

Journal: :Ambio 2011
Isla H Myers-Smith David S Hik Catherine Kennedy Dorothy Cooley Jill F Johnstone Alice J Kenney Charles J Krebs

Canopy-forming shrubs are reported to be increasing at sites around the circumpolar Arctic. Our results indicate expansion in canopy cover and height of willows on Herschel Island located at 70 degrees north on the western Arctic coast of the Yukon Territory. We examined historic photographs, repeated vegetation surveys, and conducted monitoring of long-term plots and found evidence of increase...

2011
G.vanN. du Toit H. A. Snyman

________________________________________________________________________________ Abstract Grazing levels and rotational schemes need to be tailored to each individual farm or pasture, and more studies are needed on the resilience of rangelands and on separating the effects of grazing and climate. The direct short-term impact of three rates of stocking (4, 8 and 16 Small Stock Units-SSU/ha) was ...

2013
Gbadamassi G. O. Dossa Ekananda Paudel Junichi Fujinuma Haiying Yu Wanlop Chutipong Yuan Zhang Sherryl Paz Rhett D. Harrison

Tropical volcanoes are an important but understudied ecosystem, and the relationships between plant species diversity and compositional change and elevation may differ from mountains created by uplift, because of their younger and more homogeneous soils. We sampled vegetation over an altitudinal gradient on Mt. Rinjani, Lombok, Indonesia. We modeled alpha- (plot) and beta- (among plot) diversit...

ژورنال: علوم آب و خاک 2001
بنی هاشمی, ضیاءالدین, حمزه زرقانی, حبیب ‌الله,

A field survey was carried out in Firoozabad Beneh (Pistacia mutica) Forest Station covering about 12000 hectares. Data were collected using combined random and systematic sampling methods to study the effect of altitude, dominant slope direction, sex and age of the host and plant canopy on rust severity caused by Pileolaria terebinthi. The rust severity decreased with plant age and elevation...

Journal: :Remote Sensing 2013
Hans D. Roelofsen Peter M. van Bodegom Lammert Kooistra Jan-Philip M. Witte

Estimating plant traits in herbaceous plant assemblages from spectral reflectance data requires aggregation of small scale trait variations to a canopy mean value that is ecologically meaningful and corresponds to the trait content that affects the canopy spectral signal. We investigated estimation capacities of plant traits in a herbaceous setting and how different trait-aggregation methods in...

2013
Philipp R Semenchuk Bo Elberling Elisabeth J Cooper

The High Arctic winter is expected to be altered through ongoing and future climate change. Winter precipitation and snow depth are projected to increase and melt out dates change accordingly. Also, snow cover and depth will play an important role in protecting plant canopy from increasingly more frequent extreme winter warming events. Flower production of many Arctic plants is dependent on mel...

2016
Luke Wallace Arko Lucieer Darren Turner Juha Hyyppä Xinlian Liang

This study investigates the potential of unmanned aerial vehicles (UAVs) to measure and monitor structural properties of forests. Two remote sensing techniques, airborne laser scanning (ALS) and structure from motion (SfM) were tested to capture three-dimensional structural information from a small multi-rotor UAV platform. A case study is presented through the analysis of data collected from a...

Journal: :Journal of Agricultural Meteorology 1972

Journal: :Annals of botany 2010
Ian R Johnson John H M Thornley Jonathan M Frantz Bruce Bugbee

BACKGROUND AND AIMS The distribution of photosynthetic enzymes, or nitrogen, through the canopy affects canopy photosynthesis, as well as plant quality and nitrogen demand. Most canopy photosynthesis models assume an exponential distribution of nitrogen, or protein, through the canopy, although this is rarely consistent with experimental observation. Previous optimization schemes to derive the ...

Journal: :international journal of aquatic biology 0
arunkumar shetty department of p.g. studies and research in applied zoology, kuvempu university, shankaraghatta, 577 451 karnataka. mididodi venkateshwarlu department of p.g. studies and research in applied zoology, kuvempu university, shankaraghatta, 577 451. karnataka. murugan muralidharan sri paramakalyani centre for environmental scieces, manonmaniam sundaranar university, alwarkurichi, 627 412. tamilnadu

the fish assemblage and diversity in relation to water quality of three coastal rivers sita, swarna and varahi of udupi district, karnataka, india was studied. 71 species representing 7 orders, 20 families and 41 genera were recorded from 21 sites along the three rivers. species composition varied longitudinally in relation to the environmental factors of the habitat. the downstream change in t...

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