نتایج جستجو برای: destruction of natural habitats

تعداد نتایج: 21201521  

   Background and aims: Mosquitoes (Diptera: Culicidae) are still a focus of research because of their role in the transmission of diseases and annoying biting behavior. Source reduction is an effective measure to control mosquito populations, which is based on good knowledge of larval habitats. This study was conducted to obtain that basic knowledge in Chaharmahal and Bakhtiari province....

Journal: :Developmental and comparative immunology 1999
C Carey N Cohen L Rollins-Smith

Many, but not all, amphibian populations have been declining on all six continents on which they live. Although habitat destruction, direct application of toxicants, and introduction of predators/competitors are obvious causes of amphibian declines, many amphibians are dying of infectious diseases in relatively pristine habitats on several continents. In this paper, we review the patterns of th...

2002
David Simpson R. David Simpson

The destruction of natural habitats has prompted concerns about the loss of biological diversity. Regrettably, however, there is no consensus among either biologists or economists on the most meaningful measures of biodiversity. Fundamentally different definitions are useful in asking fundamentally different questions. Considerable attention has been given to the value of diversity in search mo...

Journal: Journal of Herbal Drugs 2013
Abdollah Ghasemi Pirbalouti, Gholamreza Bajhian Leyla Mehravar Mojtaba Jafarnia

Background & Aim: Myrtle (Myrtus communis L.), is an important medicinal plant that is used for pharmacological uses and conservation of environments (for example preventing the soil erosion) regards to its specific condition habitat. Experimental: In this research, phytochemical variations of the essential oils from different populations of myrtle collected from Fars (Saydan, Cheshme-Ali, and ...

2001
Tom Arbuckle Volker Steinhage Dieter Wittmann

Bees, as the main pollinators of food crops, represent a critical natural resource which needs to be carefully exploited and managed. In recent years, however, destruction of bee's native habitats, infestations, and displacements of native bees by alien bee species have reduced and disturbed bee populations and this is already having considerable impact on global agriculture. A further concurre...

Journal: :Trends in ecology & evolution 2004
Jonathan Silvertown

Sustainable exploitation is widely advocated as a strategy for reconciling economic pressures upon natural habitats with nature conservation. Two recent papers examine different aspects of the sustainability of the nut harvest on wild populations of Brazil nut trees Bertholletia excelsa in Amazonia. Peres et al. find that many populations of the Brazil nut tree lack juvenile trees and are not r...

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