دانلود مقاله انگلیسی رایگان:مدل سازی توده های سالانه تهاجمی چمن در مناطق ساحلی سرد صحرای غربی ایالات متحده غربی - 2020
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  • Modeling Invasive Annual Grass Abundance in the Cold Desert Ecoregions of the Interior Western United States Modeling Invasive Annual Grass Abundance in the Cold Desert Ecoregions of the Interior Western United States
    Modeling Invasive Annual Grass Abundance in the Cold Desert Ecoregions of the Interior Western United States

    سال انتشار:

    2020


    عنوان انگلیسی مقاله:

    Modeling Invasive Annual Grass Abundance in the Cold Desert Ecoregions of the Interior Western United States


    ترجمه فارسی عنوان مقاله:

    مدل سازی توده های سالانه تهاجمی چمن در مناطق ساحلی سرد صحرای غربی ایالات متحده غربی


    منبع:

    Sciencedirect - Elsevier - Rangeland Ecology & Management, 73 (2020) 171-180: doi:10:1016/j:rama:2019:09:003


    نویسنده:

    John C. Hak*, Patrick J. Comer


    چکیده انگلیسی:

    Invasive annual grasses, primarily Bromus tectorum, are a severe risk to native vegetation of the intermountainWest. Once established, annual grasses alter natural fire regimes and outcompete natives until, in some places, they become the overwhelming dominant. We developed a regional spatial model encompassing eight ecoregions to indicate the relative abundance of invasive annual grass at five levels of canopy cover. We used field sample data representing invasive annual grass abundance to build and calibrate the model. Explanatory variables, represented as map inputs, included image indices, climate, landform, soil, and human-induced surface disturbance. As a novel modeling approach, we built multiple models based on classes of invasive annual grass cover abundance were developed individually and then combined into a final 90-m pixel resolution model that indicates locations relative to invasive annual grass abundance into classes of < 5%, 515%, 1625%, 2645%, and > 45% cover. Each component model was validated using held-out sample data, and relative accuracy was 86%, 74%, 62%, 62%, and 60%, respectively, with an overall kappa of 0.773. The Columbia Plateau, Northern Basin and Range, and Snake River Plain ecoregions appear to have the greatest overall proportions (4862%) mapped within at least one of the invasive cover categories. Overlay of the resulting model with major vegetation types indicated > 50 major vegetation types that are affected by current distribution of annual grasses and are at risk of expansion. Among these, Intermountain Basins, Big Sagebrush Steppe, and Columbia Plateau Steppe and Grassland each consistently scored high for invasive risk where they occur. Spatial models of this type should assist with rangeland restoration and for decisions involving placement of infrastructure, vegetation treatments where further surface disturbance could trigger additional cheatgrass expansion. Options exist for extending this model, using climate projections over upcoming decades, to indicate areas of increasing risk for invasion.
    Key Words: ecological condition | ecological integrity | human footprint | human modification | invasive annual grass | weeds


    سطح: متوسط
    تعداد صفحات فایل pdf انگلیسی: 10
    حجم فایل: 2363 کیلوبایت

    قیمت: رایگان


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