نتایج جستجو برای: steppe rangelands

تعداد نتایج: 6506  

2011
SAMUEL D. FUHLENDORF DAVID M. ENGLE

Rangelands are the most common form of terrain WE PROPOSE A PARADIGM THAT in both the United States (where it accounts for 61% of all land surface) and the world (70% of all land surface). ENHANCES HETEROGENEITY Rangelands consist primarily of native plant communities managed, typically, for livestock production (Holechek et al. INSTEAD OF HOMOGENEITY TO PROMOTE 1998). Because they can embrace ...

2012
S. A. Zimov N. S. Zimov A. N. Tikhonov F. S. Chapin

At the last deglaciation Earth’s largest biome, mammoth-steppe, vanished. Without knowledge of the productivity of this ecosystem, the evolution of man and the glacialeinterglacial dynamics of carbon storage in Earth’s main carbon reservoirs cannot be fully understood. Analyzes of fossils 14C dates and reconstruction of mammoth steppe climatic envelope indicated that changing climate wasn’t a r...

2012
S. Aghainajafi Zadeh M. R. Hemami F. Heydari

Knowledge of food resource of the houbara which an endangered species would be a important step toward the preservation of this bird. Adequate study has not been done in this field and therefore the food sources of the houbara during the brooding season was studied in the central steppe of Iran. In order to determine the density of insect in plant communities the pitfall trap was used , positio...

2012
Ping Zhang Shiping Chen Wenli Zhang Haixia Miao Jiquan Chen Xingguo Han Guanghui Lin

Aims Ecosystem carbon models often require accurate net ecosystem exchange of CO2 (NEE) light-response parameters, which can be derived from the Michaelis–Menten equation. These parameters include maximum net ecosystem exchange (NEEmax), apparent quantum use efficiency (a) and daytime ecosystem respiration rate (Re). However, little is known about the effects of land conversion between steppe a...

Journal: :مرتع و آبخیزداری 0
قادر کریمی استادیار پژوهشی، بخش تحقیقات مرتع، مؤسسه تحقیقات جنگل ها و مراتع کشور، ایران حسن یگانه استادیار، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران حسن براتی کارشناس ارشد مرتعداری، دانشکده منابع طبیعی، دانشگاه تهران، ایران

rangelands have been composed of different plant species that emergence of phenological stages in every one of them will be influenced by environmental and genetic factors. in order to exploit the time and achieve acceptable performance in each plant species, it is necessary that the emergence of biological phenomena are recorded and studied. the objective of the present study is to survey the ...

Journal: :African Journal of Range & Forage Science 2021

(2021). Montane rangelands in a changing world. African Journal of Range & Forage Science: Vol. 38, Rangelands Changing World, pp. iii-vi.

2013
Matt Lavin Tyler J Brummer Ryan Quire Bruce D Maxwell Lisa J Rew

Fire is thought to profoundly change the ecology of the sagebrush steppe. The Idaho National Laboratory provides an ideal setting to compare the effects of fire and physical disturbance on plant diversity in high-native-cover sagebrush steppe. Seventy-eight 1-hectare transects were established along paved, green-striped, gravel, and two-track roads, in overgrazed rangeland, and within sagebrush...

2016
Anne Kemmling Birgit Pfeiffer Rolf Daniel Michael Hoppert A. Kemmling M. Hoppert

Biological Soil Crusts (BSCs), consisting of prokaryotes, microalgae, lichens, mosses and eventually small vascular plants, cover wide areas in arid and semi-arid environments. In the present study, the microbial diversity of these crusts was explored at extrazonal mountain steppe sites in the western Khentej (Northern Mongolia). At the study site the Siberian taiga borders on the Mongolian-Dau...

2007
Marilyn D. Walker Donald A. Walker Kaye R. Everett Susan K. Short MARILYN D. WALKER

The hypothesized presence of large regions of grass and forb-dominated "steppe tundra" across Alaska and Siberia during the Pleistocene glacial epochs has led to a search for modern analogs. Evidence is presented for the presence of steppe vegetation on south-facing slopes and summits of pingos within the central Arctic Coastal Plain of Alaska. Vegetation, floristics, soils, and climatic factor...

2010
Grant D. Zazula Glen MacKay Thomas D. Andrews Beth Shapiro Brandon Letts Fiona Brock

A partial steppe bison (Bison priscus) carcass was recovered at Tsiigehtchic, near the confluence of the Arctic Red and Mackenzie Rivers, Northwest Territories, Canada in September of 2007. The carcass includes a complete craniumwith horn cores and sheaths, several complete post-cranial elements (many of which have some mummified soft tissue), intestines and a large piece of hide. A piece of me...

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