In 1995, the "landscape security pattern theory" was put forward. He believes that every point, line and surface in the landscape plays a different role in the landscape process, and there are some key points (or strategic points) and some specific patterns, which play a potentially decisive role in the landscape process, thus forming a safe pattern to control the landscape [160].
The construction principle of land use security pattern in mining area is to follow the idea of natural evolution, pay attention to maintaining and restoring the continuity and integrity of landscape ecological process and pattern, and combine the reclamation and construction of abandoned land in mining area with complete pattern, extended natural interface, biological channel connection, limited landscape interference and reduced ecological footprint to plan and construct a healthy land use security pattern coordinated inside and outside the mining area.
The security model of land use in mining area applies the principle of landscape ecology, considers the comprehensive ecological characteristics and specific target requirements of mining area, and constructs a mining area ecosystem with harmonious spatial structure, ecological stability and ideal social and economic benefits. Among the landscape ecological models of land use in mining areas, there are typical models of combination of agglomeration and dispersion and ecological network construction.
4. 1.2. 1 mode of combination of agglomeration and dispersed phase
It is the main theoretical basis for optimizing the spatial pattern of land use. The landscape ecological planning model proposed by American landscape ecologist Forman [16 1] based on the ecological space theory is considered as the best landscape pattern in ecology. This pattern includes the following landscape ecological attributes: ① using large areas of natural vegetation patches to conserve water and maintain the survival of key species; (2) Granularity, including large patches and small patches, meets the diversity of the whole landscape and local points; ③ Small natural vegetation patches are used as temporary habitats or shelters; (4) Corridor is used for species diffusion and material energy flow. This model emphasizes the centralized use of land, maintains the integrity of large natural vegetation patches and gives full play to their ecological functions; Guide and design natural patches to spread to areas controlled by human activities or agricultural areas in the form of corridors or small patches; At the same time, some small artificial patches are designed along natural vegetation patches and corridors in human activity areas. Through the adjustment of landscape spatial structure, various patches are concentrated and dispersed, the heterogeneity of landscape is established, and ecological protection is realized, thus maintaining biodiversity and expanding visual diversity.
4. 1.2.2 ecological network model
The fragmentation of natural habitat has formed many natural habitat patches, and the increase of fragmentation and isolation between these isolated natural patches has led to the extinction of some animal and plant populations. The concept of ecological network was put forward when people studied the fragmentation and isolation of natural habitats. Ecological network connects various separated ecosystems and is the most common structure in landscape. Species move along the ecological network, which affects the surrounding landscape matrix and patch community.
In the ecological network model, connectivity, stepping stones, core areas and heterogeneous populations are all important factors [162]. Generally speaking, an ecological network is often composed of core area, ecological buffer area and connecting area. The core area is an area with high ecological value and belongs to the absolute protected area; Ecological buffer zone is a buffer zone for protecting the core area and for the purpose of resource protection or landscape restoration Connecting zone is an area to maintain and promote the migration of some species within and between core areas.