Landscape Pattern and landscape index

Landscape Pattern and landscape index

Landscape pattern usually refers to the spatial structure characteristics of the landscape. It refers to the natural or man-made structure. A series of different sizes and shapes arrange different landscapes in the landscape space, it is the specific manifestation of landscape heterogeneity and the result of various ecological processes, including interference, on different scales. Spatial plaque is the most common form of landscape pattern, which is manifested on different scales. Landscape Pattern and Its changes are a comprehensive reflection of the regional ecological environment system generated by the interaction of natural and man-made factors, the type, shape, size, quantity, and space combination of landscape patches are not only the result of the interaction of various interference factors, but also affect the ecological process and Edge Effect of the region. Different landscape types play a different role in maintaining biodiversity, protecting species, improving the overall structure and function, and promoting the natural evolution of landscape structures. At the same time, different landscape types have different resistance to external interference. Therefore, the study of Landscape Spatial Pattern in a region is an effective means to reveal the ecological condition and spatial variation characteristics of the region. Different Ecological Structures in the study area can be divided into landscape unit patches. through quantitative analysis of the characteristics index of the landscape spatial pattern, the regional ecological environment conditions can be given from a macro perspective.

The basic elements of landscape structure include matrix, patches, corridors, and spatial configuration of elements. In terms of structure, the landscape pattern can be divided into point pattern, line pattern, and grid pattern. Point pattern refers to a landscape type in which the plaque size of a specific landscape type is much less than the distance between them. Line Pattern refers to the spatial distribution of landscape elements in a long band; grid Bureau is a combination of point pattern and line pattern. The spatial distribution of landscape elements can also be divided into a uniform distribution pattern, a clustered distribution pattern, and a specific combination pattern.

The landscape pattern index includes the following indicators:

(1) Landscape fragmentation

Fragmentation represents the fragmentation degree of the landscape, reflecting the complexity of the landscape space structure, and to some extent reflecting the degree of human interference to the landscape. It is a process in which the landscape tends to be complex, heterogeneous, and non-consecutive patches embedded by a single, homogeneous, and continuous whole due to natural or man-made interference, landscape fragmentation is one of the important reasons for the loss of biodiversity, which is closely related to the protection of natural resources. The formula is as follows:

Ci = Ni/AI

CI is the fragmentation of landscape I, Ni is the number of patches of landscape I, and AI is the total area of landscape I.

(2) Landscape Separation

The degree of separation of individual distributions of different patches in a landscape type.

Vi = dij/AIJ

In formula, VI is the separation degree of landscape type I, dij is the distance index of landscape type I, and AIJ is the area index of landscape type I.

(3) interference intensity and naturalness

Interference intensity indicates human interference, and the smaller the interference intensity, the more beneficial it is to biological survival. Therefore, the greater ecological significance it has for receptor.

Wi = Li/Si; ni = 1/wi

Wi indicates the interference intensity. Li refers to the total length of corridors (roads, railways, dams, ditches) in the I-type ecosystem, and Si refers to the total area of the I-type ecosystem, ni is the nature of the I-type ecosystem.

(4) Landscape Diversity Index

The diversity index refers to the diversity of landscape elements or ecosystems in terms of structure, function, and changes over time. It reflects the richness and complexity of landscape types. The calculation formula is as follows:

In formula, H is the diversity index, Pi is the proportion of area of landscape type I, and m is the number of landscape types. The greater the H value, the greater the landscape diversity.

(5) superiority

D is the dominant position of the landscape, which is inversely proportional to the diversity index. For different landscapes with the same number of landscape types, the larger the diversity index, the smaller the dominant position.

(6) Uniformity

E = (H/hmax) ×100%

Uniformity is the same as dominance, and it also describes the degree to which the landscape is controlled by a few major landscape types. The two indexes can be mutually verified.

(7) dimension

D = 2Ln (P/4)/ln ()

In formula, D indicates the segmentation dimension, P indicates the perimeter of the patches, and a indicates the area of the patches. The larger the D value, the more complex the plaque shape. The theoretical range of D value is 1.0 ~ 2.0 and 1.0 represent the simplest square patches, and 2.0 represent the most complex patches around the same area.

(8) clustering index

Rc = 1-C/Cmax

In formula, RC is the relative clustering index, and the value range is 0 ~ 1; C is the complexity index, and Cmax is the maximum possible value of C. The formula for calculating C and Cmax is:

P (I, j) is the probability that the ecosystem I is adjacent to the ecosystem J, and m is the total number of ecosystem types in the landscape. In actual calculation, P (I, j) can be estimated by the following formula: P (I, j) = E (I, j)/Nb, in the formula E (I, j, j) is the boundary length between adjacent ecosystems I and j, and Nb is the total boundary length between different ecosystems in landscape. The larger the value of RC, the landscape is composed of a few large patches. The smaller the value of RC, the landscape is composed of many small patches.

Calculating the landscape index of a region can help you understand and evaluate the region's landscape and land use patterns (see figure 4 ), the Calculation of landscape indexes in different time periods can also analyze the landscape pattern changes and the trend of land use evolution in the region, and analyze the driving factors and development trends of these changes, it provides reference for later planning. In short, the analysis of landscape pattern helps increase the degree of understanding of the landscape in the Planning area, and then adjust or build a new landscape structure by combining or introducing new landscape elements, to increase landscape heterogeneity and stability, this is an important part of landscape planning and design.