نتایج جستجو برای: annual forbs
تعداد نتایج: 110865 فیلتر نتایج به سال:
—Pocket gophers have the potential to alter the dynamics of grasslands by creating mounds that bury existing vegetation and locally reset succession. Gopher mounds may provide safe sites for less competitive species, potentially increasing both species diversity and vegetation heterogeneity (spatial variation in species composition). We compared species composition, diversity and heterogeneity ...
This study examined the impact of logs and stumps on the understory composition of 28-yearold aspen-dominated boreal forests. Suitable logs covered more than five times the area of stumps in both harvest and wildfire stands. Logs and stumps were colonized by a significantly different assemblage of vascular plants than the forest floor. Initial colonization patterns on dead wood in both wildfire...
The present study was performed to identify diversity indices of herb layer functional groups and its relation to physiographical factors in central Zagros forest, Lorestan. For this purpose, sampling of herbaceous plants was conducted randomly in plots of 2×2 m (n=50) in site. All plants were classified to functional groups including forbs, graminoids and legumes, also Raunkiaerchr('39')s life...
Snowmelt in alpine ecosystems brings ample water, and together with above-freezing temperatures, initiates plant growth. In this scenario, rapid activation of photosynthesis is essential for a successful life-history strategy. But, strong solar radiation late spring enhances the risk photodamage, particularly before fully functional. We compared photoprotective strategy five forbs: one geophyte...
Sudan is a large country with an area of 1.88 million Km2, and has the second largest animal population in Africa consisting of 52.08 million sheep, 43.44 million goats, 41.76 million cattle and 4.62 million camels (MARF, 2013). The majority of animal wealth is concentrated in western Sudan (40%), followed by central Sudan (23%) (MARF, 2011). Minerals are divided into two groups, macro-minerals...
In most ecosystems, disturbance is an important agent of variation in community structure and composition. Determining the diversity and composition of soil seed bank is essential for designing conservation and restoration programs because it can markedly contribute to future plant communities. Despite the important role of soil seed banks in the composition of different plant communities, and...
تولید خالص اولیه یکی از مهمترین ویژگی کارکرد نظامهای بوم شناختی است که تحت تأثیر عاملهای زیستی و اقلیمی میباشد. هدف پژوهش حاضر تعیین قابیلت مدل CASA برای برآورد توزیع زمانی و مکانی تولید خالص اولیه NPP در مناطق خشک با کمک تصاویر مودیس و لندست در تیپهای گیاهی مختلف است. به این منظور دادههای مورد نیاز تصاویر ماهوارهای و هواشناسی از قبیل: بارش، دما و ساعات آفتابی ماهانه تهیه شد. مقدار تولید...
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