Evaluation of ecological security and ecological maintenance based on pressure-state-response (PSR) model, case study: Fuzhou city, China

Figures & data

Figure 1. Geographical location of Fuzhou City (a is the provincial administrative division of China, b is the location of Fuzhou city in Fujian province, and c is the elevation of the district and county administrative divisions of Fuzhou City.).

Table 1. Research data and sources.

Data	Spatial resolution/Type	Data source
Remote sensing image	30m	Geospatial data cloud (http://www.gscloud.cn/)
DEM	30m	Geospatial data cloud (http://www.gscloud.cn/)
Land use type data	30m	Globeland30(http://globeland30.org/)
Statistical yearbook	Numerical Data	Fuzhou Statistics Bureau (http://tjj.Fuzhou.gov.cn/)
Basic geographic data (Administrative division data and highway network data)	Vector	Resources and environmental science and data center, Chinese Academy of Sciences (https://www.resdc.cn/Default.aspx)

Figure 2. Flow chart of this study.

Figure 3. Ecological security analysis framework based on PSR model.

Table 2. Calculation method of PSR model index factors in Fuzhou.

Index	Calculation method	Method statement
Highway density	Grid method	Create grids and assign values in ArcGIS software.
Population density
Per capita cultivated area
Per capita output of grain
Water coverage
GDP per capita
Regional development degree
Elevation	DEM	DEM is elevation, Slope and Topographic relief height are generated in ArcGIS software.
Slope
Topographic relief height
Vegetation coverage	$\mathit{FVC}=\frac{\mathit{NDVI}-{\mathit{NDVI}}_{\mathit{soil}}}{{\mathit{NDVI}}_{\mathit{veg}}-{\mathit{NDVI}}_{\mathit{soil}}}$ $\mathit{NDVI}=\frac{{\rho }_{\mathit{nir}}-{\rho }_{\mathit{red}}}{{\rho }_{\mathit{nir}}+{\rho }_{\mathit{red}}}$	$\mathit{FVC}$ is the regional vegetation coverage, ${\mathit{NDVI}}_{\mathit{soil}}$ is the naked soil pixel without vegetation coverage, and ${\mathit{NDVI}}_{\mathit{veg}}$ is the pure vegetation coverage pixel. $\mathit{NDVI}$ is the normalized vegetation index, ${\rho }_{\mathit{nir}}$ and ${\rho }_{\mathit{red}}$ are the near infrared band and red band of each Landsat sensor respectively.
Ecological elasticity	$\mathrm{ }{\mathit{ECO}}_{\mathit{res}}={\sum }_{i=1}^n(S_i\times P_i)\mathrm{ }$	${\mathit{ECO}}_{\mathit{res}}$ is ecological elasticity, $S_i$ is the percentage of the area of category $i$ landscape type; $P_i$ is the ecological elasticity score of category $i$ landscape type.
Surface temperature	$B\left(TS\right)=\frac{\left[L\lambda －L\uparrow －\tau \left(1－\epsilon \right)L\downarrow \right]}{\tau \epsilon }\mathrm{ }$ $\mathrm{ }TS=\frac{K2}{\ln [K1/B(TS)+1]}\mathrm{ }$	$B\left(TS\right)$ is the radiation brightness value of the black body whose temperature is $TS$ in the thermal infrared band; $L\lambda$ is the calibration value of atmospheric radiation in thermal infrared band; ε is the surface emissivity value; The transmittance of τ atmosphere in infrared band; $L\uparrow$ and $L\downarrow$ are the brightness of upward and downward atmospheric radiation respectively; TS is the real surface temperature, $K1$ and $K2$ are the preset constants of the sensor before satellite launch.
Intensity of human interference	$\mathrm{ }\mathit{HAI}={\sum }_{i=1}^n\left(S_i\frac{P_i}{TA}\right)\mathrm{ }$	$\mathit{HAI}$ represents the human disturbance index, $S_i$ represents the total area of type $i$ landscape, $n$ represents the total number of landscape types, $P_i$ represents the parameter of human influence intensity of type $i$ landscape, and $TA$ represents the total area of landscape.
Landscape diversity	$\mathit{SHDI}=-{\sum }_{i=1}^n(p_i\times \ln p_i)\mathrm{ }$	$\mathit{SHDI}$ is the landscape diversity index, $n$ represents the total number of landscape types in each grid, and $p_i$ represents the area proportion of type $i$ landscape in each grid.

Table 3. Evaluation index system of land ecological security in Fuzhou.

Target layer	Rule layer	Index layer	Index trend	Data source	Weight
Ecological security evaluation system of Fuzhou	Pressure layer	Highway density	Negative	Basic geographic data	0.0245
		Population density	Negative	Statistical yearbook	0.1107
		Per capita cultivated area	Negative	Statistical yearbook	0.0586
		Per capita output of grain	Negative	Statistical yearbook	0.0373
	State layer	Elevation	Negative	DEM	0.0402
		Slope	Negative	DEM	0.1332
		Topographic relief	Negative	DEM	0.1068
		Vegetation coverage	Positive	Remote sensing image	0.1098
		Water coverage	Positive	Land use data	0.0137
		Ecological elasticity	Positive	Land use data	0.0271
		Surface temperature	Negative	Land use data	0.0903
		Intensity of human interference	Negative	Land use data	0.0527
		Landscape diversity	Positive	Land use data	0.0913
	Response layer	GDP per capita	Positive	Statistical yearbook	0.0865
		Regional development degree	Negative	Land use data	0.0173

Figure 4. Factor weight and trend of ecological security index in Fuzhou.

Figure 5. Spatial distribution of land use types in Fuzhou.

Table 4. Transfer matrix of land use type change in Fuzhou (km²).

Period	Land use type	Grass Land	Cultivated Land	Artificial Surfaces	Forest	Bare Land	Wetland	Water Body
2000—2010	Grass Land	745.52	0.03	4.52	0.61	0.00	0.00	1.58
	Cultivated Land	0.54	3011.39	50.83	85.95	0.00	0.00	4.29
	Artificial Surfaces	0.13	0.44	458.37	1.00	0.00	0.00	0.11
	Forest	0.07	0.18	27.30	6679.27	0.00	0.00	8.71
	Bare Land	0.00	0.05	5.15	0.17	58.98	0.00	0.15
	Wetland	0.00	0.00	0.39	0.00	0.00	128.37	0.02
	Water Body	0.05	0.00	0.00	0.02	0.00	0.00	455.49
2010—2020	Grass Land	440.72	40.04	21.21	229.54	7.71	0.40	6.28
	Cultivated Land	43.72	2459.99	272.55	163.01	3.36	4.86	63.55
	Artificial Surfaces	2.03	30.96	504.29	4.11	0.66	0.33	4.09
	Forest	235.60	143.55	53.33	6292.32	13.77	1.70	24.49
	Bare Land	6.78	2.08	4.97	20.23	20.29	0.20	4.36
	Wetland	1.79	2.29	16.76	5.47	0.16	72.99	28.46
	Water Body	4.19	15.88	63.64	19.82	1.54	40.65	322.31
2000—2020	Grass Land	440.97	40.06	25.34	230.94	7.72	0.40	6.40
	Cultivated Land	44.61	2466.51	320.63	244.22	3.40	5.56	67.12
	Artificial Surfaces	1.77	26.50	423.75	3.48	0.56	0.29	3.62
	Forest	235.00	141.81	76.91	6219.34	13.78	1.60	24.86
	Bare Land	6.79	2.08	9.85	20.46	20.35	0.20	4.68
	Wetland	1.79	2.29	17.14	5.48	0.16	72.99	28.48
	Water Body	3.92	15.54	63.13	10.77	1.53	40.09	318.39

Figure 6. Dynamic attitude of land use in Fuzhou from 2000 to 2020.

Table 5. Parameters of human interference intensity in Fuzhou.

Land use type	Cultivate Land	Forest	Grass Land	Wetland	Water Body	Artificial Surfaces	Bare Land
Parameter	0.55	0.1	0.23	0.105	0.115	0.95	0.075

Table 6. Ecological elasticity score of Fuzhou city.

Land-use type	Elasticity score	Specify
Cultivate Land	37	It has certain significance to maintain the elasticity of the regional ecosystem and must be carefully used.
Forest	95	It is of decisive significance to maintain and regulate the elasticity of the regional ecosystem.
Grass Land	67	Grassland maintenance and management can increase the resilience limit of the area.
Wetland	61	It is of great significance to maintaining the elasticity of the regional ecosystem and must be strengthened in management and maintenance.
Water Body	59	It is of great significance to maintaining the elasticity of the regional ecosystem and must be strengthened in management and maintenance.
Artificial Surfaces	21	It has little effect on maintaining the elasticity of the regional ecosystem.
Bare Land	8	The effect on maintaining the elasticity of the regional ecosystem is very small, and even the degradation is very serious.

Figure 7. Spatial distribution of ecological security index of Fuzhou.

Figure 8. Spatial distribution of ecological maintenance in Fuzhou.

Figure 9. Area statistics of ecological maintenance degree in Fuzhou. (The three time periods are, from left to right: 2000 to 2010, 2010 to 2020 and 2000 to 2020.).

Table 7. Spatial correlation test results of ecological security index in Fuzhou.

Year	Moran index	Standard deviation	Z	P
2000	0.4502	0.0014	315.8332	0.001
2010	0.4582	0.0014	332.0072	0.001
2020	0.5147	0.0014	366.9501	0.001

Figure 10. Moran Scatter plot of Fuzhou.

Figure 11. Spatial aggregation of ecological security index in Fuzhou.

Figure 12. Obstacle degree of ecological security evaluation index in Fuzhou.