نتایج جستجو برای: habitat destruction
تعداد نتایج: 89758 فیلتر نتایج به سال:
Studies suggest that populations of different species do not decline equally after habitat loss. However, empirical tests have been confined to fine spatiotemporal scales and have rarely included plants. Using data from 89,365 forest survey plots covering peninsular Spain, we explored, for each of 34 common tree species, the relationship between probability of occurrence and the local cover of ...
Decalepis hamiltonii. Wight and Arn. (Asclepiadaceae) has been extensively used in traditional systems of medicine for a wide range of ailments. Phytochemical studies have shown the presence of many valuable compounds such as saponins, tannins, flavonoids, phenolics, triterpenes, ketones, aldelydes, resinol, sterols, inositol, fatty acids, volatile flavour compounds, cardiac glycosides, volatil...
The Atlantic Forest has a high destruction rate and there is little information available on some aspects of the neotropical bird biology. Changes in environment are important factors that affect the resources available to birds. We compared the species sensitivity level of understorey birds in two areas in distinct successional stages (primary and secondary sections). Two 100 ha plots of lowla...
Sandy coastal and inland beaches provide important habitat for shorebirds during the breeding, migration, and over-wintering seasons (Brown et al. 2000). These same beaches often are attractive to humans for recreation (Maguire et al. 2011), residential or commercial activity (Brown et al. 2010) and, in many areas, human use is intensive (De Ruyck et al. 1997). Human use of beaches can result i...
The cotton-top tamarin (Saguinus oedipus) is a critically endangered primate, endemic to the tropical forests of Colombia. Population monitoring is essential to evaluate the success of conservation efforts, yet standard survey methods are ineffective because animals flee silently before they are seen. We developed a novel technique that combines the use of playbacks of territorial vocalizations...
a spring-stream called “ghadamgah” in fars province, southern iran, which holds more than 60 aquatic vertebrate and plant species belonging to 46 genera and 33 families is almost the biologically richest water body of fars province. the diversity is especially in its endemic fishes which are under threats nowadays. one of the factors, if not the one, which has kept this system more or less in i...
Destruction and fragmentation of (semi-) natural habitats are considered the main causes of biodiversity loss worldwide. Plant species may exhibit a slow response to fragmentation, resulting in the development of an extinction debt in fragmented plant communities. The detection of extinction debt is of primary importance in habitat conservation strategies. We applied two different approaches pr...
Sitting in our offices early in the morning of September 11, 2001, we, like many across the world, watched with incredulity the twin terrorist strikes on the World Trade Centre. Riveted to the television screen, we witnessed the beginnings of a nightmare whose images will likely remain with us for a long time. September 11, and the events that followed, changed our assumptions of world terroris...
Since the late 1970s, Libyan leader Colonel Muammar Qadhafi has sought to obtain weapons of mass destruction (WMD), particularly chemical and biological weapons (CBW). By the late 1980s, Libya had developed a rudimentary capability to produce such weapons. Western experts view the pursuit of CBW as a means of bolstering Libya’s military capability, since the country lacks effective conventional...
Uncertainty about behavior: Uncertainty about behavior refers to uncertainty regarding the actions taken by others. Sometimes it is hard to know what other states are doing – in particular, if they are cooperating or defecting. Consider weapons of mass destruction. Whatever a state may say publicly, it is very difficult for others to ascertain whether it is pursuing technologies associated with...
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