نتایج جستجو برای: transects

تعداد نتایج: 2740  

Journal: Desert 2009
M. Ekhtesasi N. Mashhadi

Wind, in the duration of its erosional process, affects considerable changes in a grain's morphologyfrom its removal (detachment) step to sedimentation. In other word, a grain undergoes its gradualevolution during the transit process. In this project, the maturation of Aeolian sand grains had beenstudied upon as based on texture maturity indicator which includes: sorting, mean size grain, round...

2012
Andrew R. Gates Daniel O. B. Jones

Recovery from disturbance in deep water is poorly understood, but as anthropogenic impacts increase in deeper water it is important to quantify the process. Exploratory hydrocarbon drilling causes physical disturbance, smothering the seabed near the well. Video transects obtained by remotely operated vehicles were used to assess the change in invertebrate megafaunal density and diversity caused...

2015
Paul L. Jokiel Kuʻulei S. Rodgers Eric K. Brown Jean C. Kenyon Greta Aeby William R. Smith Fred Farrell

Nine coral survey methods were compared at ten sites in various reef habitats with different levels of coral cover in Kāne'ohe Bay, O'ahu, Hawai'i. Mean estimated coverage at the different sites ranged from less than 10% cover to greater than 90% cover. The methods evaluated include line transects, various visual and photographic belt transects, video transects and visual estimates. At each sit...

2016
José M. V. Fragoso Taal Levi Luiz F. B. Oliveira Jeffrey B. Luzar Han Overman Jane M. Read Kirsten M. Silvius

Conservation of Neotropical game species must take into account the livelihood and food security needs of local human populations. Hunting management decisions should therefore rely on abundance and distribution data that are as representative as possible of true population sizes and dynamics. We simultaneously applied a commonly used encounter-based method and an infrequently used sign-based m...

2015
Juliano Sarmento Cabral Gunnar Petter Glenda Mendieta-Leiva Katrin Wagner Gerhard Zotz Holger Kreft Ben Bond-Lamberty

Local variation in the abundance and richness of vascular epiphytes is often attributed to environmental characteristics such as substrate and microclimate. Less is known, however, about the impacts of tree and branch turnover on epiphyte communities. To address this issue, we surveyed branches and epiphytes found on the forest floor in 96 transects in two forests (Atlantic rainforest in Brazil...

2006
J. S. Linneman M. W. Palmer

We established transects under twenty Juniperus virginiana trees that invaded an unburned central Oklahoma grassland within the last 20 years to determine their effects on plant species composition. Species richness and stem density increased as distance from the trunk increased. Stem density was also higher towards the south side of trees. Graminoid, forb and total cover were related to distan...

2005
M. J. Lindstrom T. E. Schumacher D. E. Lobb D. D. Malo

Soil carbon (C) losses and soil translocation from tillage operations have been identified as causes of soil degradation and soil erosion. The objective of this work was to quantify the variability in tillage-induced carbon dioxide (CO2) loss by moldboard (MP) and chisel (CP) plowing across an eroded landscape and relate the C loss to soil properties. The study site was a 4 ha wheat (Triticum a...

2015
Ernesto Medina Marta Francisco Leonel Sternberg William T. Anderson

The Sr, C, and N isotopic signatures of organic matter in sediments from the continental shelf facing the Orinoco Delta were measured to determine the contribution of sediments transported from the Amazon River by the coastal Guayana current and the sediments transported by the Orinoco River. Box core samples between 60 and 300 m water depth collected along 4 transects located eastwards to the ...

2008
M.J.C. Crabbe

In this study I investigated the hypothesis that alterations in macroalgal cover significantly influenced the growth rates of coral colonies on the fringing reefs of Discovery Bay, Jamaica. For colonies of Montastrea annularis, Porites astreoides, and Sidastrea siderea, radial growth rates were significantly (p<0.02) higher at Dairy Bull (where Diadema antillarum had removed macroalgal cover) t...

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