نتایج جستجو برای: plant cover

تعداد نتایج: 497813  

Journal: :The American naturalist 2002
Johan van de Koppel Max Rietkerk Frank van Langevelde Lalit Kumar Christopher A Klausmeier John M Fryxell John W Hearne Jelte van Andel Nico de Ridder Andrew Skidmore Leo Stroosnijder Herbert H T Prins

Recent theoretical studies have shown that spatial redistribution of surface water may explain the occurrence of patterns of alternating vegetated and degraded patches in semiarid grasslands. These results implied, however, that spatial redistribution processes cannot explain the collapse of production on coarser scales observed in these systems. We present a spatially explicit vegetation model...

Journal: :journal of rangeland science 2013
naghmeh gholami baghi adel sepehri hossein barani salman abdol-rasoul mahini

plant biomass is an important factor for determining arid and semi-aridrangelands capacity. due to the lack of proper and annual sampling of rangelands, there areno suitable data to determine biomass, range condition and proper range managementoperations. plant biomass is one of the measurable attributes that can be assessed inrangeland studies. since the clip and weight method is destructive a...

ژورنال: علوم زراعی ایران 2022

Inclusion of cover crops in crop rotations has several benefits such as supplying nitrogen for the next crop. To investigate the effect of cover crops and different levels of nitrogen fertilizer on tuber yield, yield components, and different nitrogen efficiency indices of potato, a filed experiment was conducted as split plots arrangements in randomized complete block design with three replica...

2012
Jorge Luis Rentería Mark R. Gardener F. Dane Panetta Rachel Atkinson Mick J. Crawley

Originally from Asia, Rubus niveus has become one of the most widespread invasive plant species in the Galapagos Islands. It has invaded open vegetation, shrubland and forest alike. It forms dense thickets up to 4 m high, appearing to displace native vegetation, and threaten the integrity of several native communities. This study used correlation analysis between a R. niveus cover gradient and ...

2006
J. Julio Camarero Emilia Gutiérrez Marie-Josée Fortin

Aim To forecast the responses of alpine flora to the expected upward shift of treeline ecotones due to climatic warming, we investigated species richness patterns of vascular plants at small spatial scales across elevational transects. Location Richness patterns were assessed at local scales along the elevational gradient in two undisturbed treeline ecotones and one disturbed treeline ecotone i...

Journal: :Ecography 2015
Diego Nieto-Lugilde Jonathan Lenoir Sylvain Abdulhak David Aeschimann Stefan Dullinger Jean-Claude Gégout Antoine Guisan Harald Pauli Julien Renaud Jean-Paul Theurillat Wilfried Thuiller Jérémie Van Es Pascal Vittoz Wolfgang Willner Thomas Wohlgemuth Niklaus E Zimmermann Jens-Christian Svenning

The role of competition for light among plants has long been recognised at local scales, but its importance for plant species distributions at larger spatial scales has generally been ignored. Tree cover modifies the local abiotic conditions below the canopy, notably by reducing light availability, and thus, also the performance of species that are not adapted to low-light conditions. However, ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1391

in this work, a novel and fast method for direct analysis of volatile compounds (davc) of medicinal plants has been developed by holding a filament from different parts of a plant in the gc injection port. the extraction and analysis of volatile components of a small amount of plant were carried out in one-step without any sample preparation. after optimization of temperature, extraction time a...

      One of the most important issue at natural resources management is plant diversity conservation and detecting the different effects of usage methods on the its quality and quantity. This research was done with the goal of investigating the disaster center (village) at evaluation of rangeland damage with the accent of plant cover combination and diversity in Sabalan mountain southeast rang...

سید جمال الدین خواجه الدین, , محمد جعفری, , احسان زندی اصفهان, , حسین آذرنیوند, , حمید رضا کریم زاده, ,

In order to determine the reciprocal relationship between the important characteristics of soil and the growth of Haloxylon ammodendron (C.A. Mey) plant in segsi plain of Isfahan., ordination method was used. The study was performed through the stratified random sampling and the regions were separated according to the plant age and physical physiognomy, then 10 samples of Haloxylon ammodendron ...

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