نتایج جستجو برای: range establishment

تعداد نتایج: 728328  

ژورنال: مرتع 2022

Background and objectives: Problems of germination and establishment of plants in drought and dehydration conditions is one of the common problems in arid and semi-arid regions of the country which affects the growth and production of plant communities. Improvement of seed germination and establishment of plants under drought stress is one of the most important issues in success of rehabilitati...

Journal: :The American naturalist 2012
Emily I Jones Richard Gomulkiewicz

The biotic environment can pose a challenge to introduced species; however, it is not known how rapid evolution in introduced and resident species influences the probability that the introduced species will become established. Here, we analyze the establishment phase of invasion with eco-evolutionary models of introduced species involved in predator-prey, mutualistic, or competitive interaction...

Ali Ayoubian, Ehsan Teymourzadeh Gholam Hossein Alishiri Mohammadkarim Bahadori Seyed Mojtaba Hosseini

Background: It is important to set up hospitals, since they play a key role in providing health care services based on the budget allocated to the health sector. Objective:  This study evaluated factors militating against the establishment of hospitals in Iran. It also emphasized the importance of health care services. Methods: This...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده ادبیات و علوم انسانی 1391

peace and national security protection and ironic solving of international conflicts become the preliminary foundation of the united nations charter and had been considered as the main responsibilities of the security council, after world war ii and the establishment of united nations organization. therefore, the security council enables to analyze every kind of conflicts and challenges which ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان فارس - دانشکده علوم پایه 1390

سازند آب تلخ یکی از مهمترین واحدهای کرتاسه بالایی در شرق حوضه کپه داغ (شمال شرق ایران) است. سازند آب تلخ در برش مورد مطالعه 833 متر ضخامت دارد و لیتولوژی آن شامل شیل، مارن، سنگ آهک ماسه ای، ماسه سنگ آهکی و شیل می باشد. مرز زیرین سازند آب تلخ با سازند آبدراز پیوسته است اما مرز بالایی آن با سازند نیزار بصورت ناپیوستگی فرسایشی است که با یک افق 3 تا 5 سانتی متری از خاک قدیمه همراه می باشد. 113 نمون...

2017
John L. Campbell Douglas J. Shinneman

Introduction: Climate change is expected to impose significant tension on the geographic distribution of tree species. Yet, tree species range shifts may be delayed by their long life spans, capacity to withstand long periods of physiological stress, and dispersal limitations. Wildfire could theoretically break this biological inertia by killing forest canopies and facilitating species redistri...

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