نتایج جستجو برای: arid zones

تعداد نتایج: 63858  

2017
Idrissa Kaboré O. Moog A. Ouéda J. Sendzimir R. Ouédraogo W. Guenda A. H. Melcher

Awareness of sustainable management of water and its biological resources is rising in West Africa, but application of effective tools for biomonitoring and detecting habitats at risk in aquatic ecosystems is limited. In this study, we provide key environmental descriptors to characterize reference sites by applying the following "a priori criteria" (physical and chemical, hydro-morphological, ...

2014
Xiaopeng Jia Haibing Wang

The interaction of wind and water in semiarid and arid areas usually leads to low-frequency flash flood events in desert rivers, which have adverse effects on river systems and ecology. In arid zones, many aeolian dune-fields terminate in stream channels and deliver aeolian sand to the channels. Although aeolian processes are common to many desert rivers, whether the aeolian processes contribut...

Journal: :Mycologia 2008
D Wrigley de Basanta C Lado A Estrada-Torres

A new species of myxomycete, Didymium umbilicatum, isolated from the bark of Agavaceae, is described from arid zones of Mexico. This species was obtained from moist chamber cultures of Yucca spp. bark, collected in four different years from two states (Puebla and Querétaro) in central Mexico and found in the field from Hidalgo, Oaxaca and Puebla on the dead remains of Agave sp. The new species ...

2000
Sheng Gong Li Yoshinobu Harazono Takehisa Oikawa Ha Lin Zhao Zong Ying He Xue Li Chang

Overgrazing is one of the most primary causes of desertification in semi-arid zones of China. From 1992 to 1994 we conducted a grazing experiment in Naiman (lat. 42◦58′N, long. 120◦43′E, 345 m asl), Inner Mongolia, China to elucidate desertification mechanisms. Our experimental field, which was covered with some short grasses, legumes and forbs, included four plots where grazing sheep numbers d...

Journal: :Remote Sensing 2014
Sanaz Salati Frank van Ruitenbeek Freek D. van der Meer Babak Naimi

Hydrocarbon seeps cause chemical and mineralogical changes at the surface, which can be detected by remote sensing. This paper aims at the detection of mineral alteration induced by gas seeps in a marly limestone formation, SW Iran. For this purpose, the multispectral Advance Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the high spatial resolution WorldView-2 (WV-2) data we...

Journal: :Remote Sensing 2016
Romeo Mendez-Estrella Jose Raul Romo-Leon Alejandro E. Castellanos Fabiola J. Gandarilla-Aizpuro Kyle A. Hartfield

Riparian Zones are considered biodiversity and ecosystem services hotspots. In arid environments, these ecosystems represent key habitats, since water availability makes them unique in terms of fauna, flora and ecological processes. Simple yet powerful remote sensing techniques were used to assess how spatial and temporal land cover dynamics, and water depth reflect distribution of key land cov...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2016
Mark Andrew Adams Tarryn L Turnbull Janet I Sprent Nina Buchmann

Using robust, pairwise comparisons and a global dataset, we show that nitrogen concentration per unit leaf mass for nitrogen-fixing plants (N2FP; mainly legumes plus some actinorhizal species) in nonagricultural ecosystems is universally greater (43-100%) than that for other plants (OP). This difference is maintained across Koppen climate zones and growth forms and strongest in the wet tropics ...

2013
S. M. Kori A. L. Qureshi B. K. Lashari N. A. Memon

In general Pakistan is an agricultural country, most of its area including lower Indus basin (LIB) lies in arid and semi-arid zones, where irrigation by canal water and groundwater is only option. Due to continuous seepage from canal irrigation network and infiltration from irrigated lands; without adequate provision of natural and artificial drainage and its appropriate outlet, water-logging a...

Journal: :ISPRS Int. J. Geo-Information 2014
Faith Justus Danlin Yu

Greenhouse commercial horticulture in Kenya started more than two decades ago and has evolved to be a significant sector to the national economy. So far no studies have explored the spatial patterns and dynamics of the area under greenhouse cultivation. Google Earth archives alongside data from various portals provided an opportunity to study those farms’ spatial distribution. The roles of sele...

2012
D Ramesh

This study examines the marketing system of small ruminants in three different agro-climatic zones of Karnataka in India. Multistage random sampling technique was used to select 60 small ruminant farmers from three viz. Bijapur (Arid zone), Gulbarga (Semi-arid zone) and Udupi (Coastal zone) district of Karnataka state. A structured questionnaire which had earlier been subject to face validity a...

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