نتایج جستجو برای: arid zone

تعداد نتایج: 128248  

2005
Justin F. Costelloe Rodger B. Grayson Thomas A. McMahon

Australian arid zone ephemeral rivers are typically unregulated and maintain a high level of biodiversity and ecological health. Understanding the ecosystem functions of these rivers requires an understanding of their hydrology. These rivers are typified by highly variable hydrological regimes and a paucity, often a complete absence, of hydrological data to describe these flow regimes. A daily ...

2013
Mitzy Pepper Paul Doughty Matthew K. Fujita Craig Moritz J. Scott Keogh

The isolated uplands of the Australian arid zone are known to provide mesic refuges in an otherwise xeric landscape, and divergent lineages of largely arid zone taxa have persisted in these regions following the onset of Miocene aridification. Geckos of the genus Heteronotia are one such group, and have been the subject of many genetic studies, including H. spelea, a strongly banded form that o...

Journal: :Systematic biology 2012
Christoph Heibl Susanne S Renner

Among the World's most challenging environments for plant life is the Atacama Desert, an arid zone extending over 1300 km and from sea level to 2000/3000 m altitude along the southwestern Andean foothills. Plants there and in the adjacent Mediterranean zone exhibit striking adaptations, and we here address the question whether in a species-rich clade such adaptations arose in parallel, at diffe...

2017
David G Roberts Cairo N Forrest Andrew J Denham David J Ayre

Long-lived, widespread plant species are expected to be genetically diverse, reflecting the interaction between large population sizes, overlapping generations, and gene flow. Such species are thought to be resilient to disturbance, but may carry an extinction debt due to reproductive failure. Genetic studies of Australian arid zone plant species suggest an unusually high frequency of asexualit...

Journal: :Environmental Health Perspectives 1997
Jared L. Strasburg Michael Kearney Craig Moritz Alan R. Templeton

Phylogenetic and geographic evidence suggest that many parthenogenetic organisms have evolved recently and have spread rapidly. These patterns play a critical role in our understanding of the relative merits of sexual versus asexual reproductive modes, yet their interpretation is often hampered by a lack of detail. Here we present a detailed phylogeographic study of a vertebrate parthenogen, th...

Journal: :PLoS ONE 2007
Jared L. Strasburg Michael Kearney Craig Moritz Alan R. Templeton

Phylogenetic and geographic evidence suggest that many parthenogenetic organisms have evolved recently and have spread rapidly. These patterns play a critical role in our understanding of the relative merits of sexual versus asexual reproductive modes, yet their interpretation is often hampered by a lack of detail. Here we present a detailed phylogeographic study of a vertebrate parthenogen, th...

2008
J. Thomas A. H. Alfarhan A. G. Miller L. Othman

A brief analysis on the distribution range of some of the species dominating in the arid and extra arid regions of North Africa and Arabian Peninsula is presented. These species are belonging to three phytogeographical categories namely: Saharo-Sindian, Sudano-Deccanian and Tropical African-Indian elements. Species included for this study are either disjunct or they have a wider distribution, s...

2010
S. C. Jain B. Pancholi R. Singh R. Jain

Sequential extracts of some medicinally important arid zone plants of Rajasthan, viz. Lepidagathis trinervis Nees., Polycarpea corymbosa Lam. and Sericostoma pauciflorum Stocks. ex Wight. were tested against six bacterial (Gram +ve and Gram -ve) and five fungal strains using agar well diffusion method. Ethyl acetate extract of L. trinervis showed maximum activity against Bacillus subtilis, Ente...

2008
R. Warren Flint

Water resources management is one of the most important challenges to today's society. Functionally intact and biologically complex freshwater ecosystems provide many economically valuable commodities and services to society (ecosystem services), beyond simply direct water supply. Besides being an integral part of the ecosystem, water is also a social and economic good. It is therefore critical...

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...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید