کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4393036 1618256 2014 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Spatial patterns provide support for the stress-gradient hypothesis over a range-wide aridity gradient
ترجمه فارسی عنوان
الگوهای فضایی پشتیبانی از فرضیه استرس-گرادیان را بر روی یک شیب گرانشی در محدوده وسیع فراهم می کند
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
چکیده انگلیسی
We examined variations in the relative importance of facilitation vs. competition, in light of the Stress-Gradient Hypothesis (SGH) by assessing plant interactions along an aridity gradient over biogeographic scales. We surveyed the relationship between a shrub species (Artemisia tridentata) and pine seedlings (Pinus monophylla) across the Great Basin and the Mojave Desert, USA, encompassing the entire range of P. monophylla. Using 69 sites we evaluated the spatial association between P. monophylla seedlings and A. tridentata shrubs, quantified with an electivity index, and implemented multiple regression analysis on the effects of macro- and micro-environmental factors: precipitation, temperature, monsoonality index, topography, substrate and litter cover. We identified annual precipitation as a main factor, which was negatively related to shrub-seedling association. Additionally, shrub-seedling association was stronger in the hot- than in the cold-desert, and was negatively related to litter cover. Effects of monsoonality, summer temperature, and bedrock type were not significant. We also considered nonlinear functional forms of a precipitation-electivity relationship, but the negative linear model proved most predictive. Our observations match SGH predictions. Studying the role of interspecific interactions in shaping species range shifts may lead to improved predictions of distribution ranges and changes in dryland vegetation under global change scenarios.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Arid Environments - Volume 102, March 2014, Pages 27-33
نویسندگان
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