Abstract
Agricultural intensification has simplified agricultural landscapes through the expansion of agricultural land, enlargement of field size, and removal of non-crop habitats. Rural vegetation is a key component of agricultural landscapes as it produces food, fiber and fuel, and performs ecosystem services, such as recycling of nutrients, regulation of microclimate, and local hydrological processes. Vegetation classification is the basis for surveying, monitoring, and managing rural vegetation. However, to date, green space vegetation, a cultivated vegetation type, has not been listed in the vegetation classification system of China, and little is known about its functional role in the production and regulation of rural landscapes. Here, we reviewed the literatures on different vegetation classifications in China and developed a renewal framework for rural vegetation classification systems. The system includes nine classification units. First, rural vegetation is classified into three vegetation categories: natural and semi-natural vegetation, agricultural vegetation, and green space vegetation (level 0, the highest-level unit). Then, each of the highest-level units is classified into three upper level units (levels 1–3, including the vegetation formation group, vegetation formation, and vegetation subformation), three middle level units (levels 4–6, including the alliance group, alliance, and suballiance), and two lower level units (levels 7–8, including the association group and association). We clarified the division basis and nomenclature for each classification level unit with examples and proposed a reference scheme for the classification and nomenclature of rural vegetation. Following the common classification principle of “plant community ecology”, which is widely used in China, we revised the classification principles and nomenclature based on the functions of the three vegetation categories. Natural and semi-natural vegetation focus on comprehensive ecological conditions and community appearance; agricultural vegetation highlights the functional use, cultivation conditions, and farming system of crops; and green space vegetation focuses on landscape appearance and community assembly. Based on this scheme, rural vegetation in China is classified into three vegetation categories, 23 vegetation formation groups, 66 vegetation formations, and 142 vegetation subformations. Natural and semi-natural vegetation includes 6 vegetation formation groups (Forest, Shrubland, Herbaceous Vegetation, Desert, Alpine Tundra and Sparse Vegetation, and Swamp and Aquatic Vegetation), 30 vegetation formations, and 81 vegetation subformations. Agricultural vegetation includes 13 vegetation formation groups (Food Crop, Vegetable Crop, Fruit Crop, Flower Crop, Oilseed Crop, Fiber Crop, Sugar Crop, Medicine Crop, Beverage Crop, Forage Crop, Tobacco Crop, Spice Crop, and Other Crops), 23 vegetation formations, and 40 vegetation subformations. Green space vegetation includes 4 vegetation formation groups (Arbor Green Space, Shrub Green Space, Herb Green Space, and Wetland Green Space), 13 vegetation formations, and 21 vegetation subformations. This study clarified the definition boundaries of different classification units and illustrated the nomenclature of various types of vegetation in current vegetation classification research. Thus, this study modified some shortcomings in the classification and nomenclature of agricultural vegetation and renewed the vegetation classification system of China by including green space vegetation. The results of this study are beneficial for the protection, management, and spatial planning of rural landscapes.
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