ABSTRACT
The identification of ecological sources and corridors plays an important role in the construction of ecological security pattern. However, previous studies mainly concentrated on the optimal path selection of species migration and diffusion rather than the random path selection of the species, which makes most conclusions fail to objectively reveal the process of species migration and diffusion. Taking the downtown area of Hengyang City as an example, we selected the ecological sources and ecological corridors with the habitat quality analysis module of InVEST and Circuitscape 4.0 and evaluated the importance and connectivity of relevant ecological elements with the Linkage Mapper, with the aim to construct the ecological security pattern and delimitate the regions prior to ecological restoration. The results showed that there were 85 ecological sources dominated by woodland and grassland, together with a small number of ponds and beaches, which mainly distributed in the southwest of Zhengxiang District, the west of Yanfeng District, the northeast and south central of Zhuhui District, with a total area of 11.8 km2. There were 60 ecological sources with centrality greater than 100, accounting for 70.6% of the total. There were 217 ecological corridors and five potential ecological corridors mainly composed of forest land, among which the proportion of shrubbery and sparse forest land was higher. The corridors with higher importance were mainly distributed in the west of the studied area. After removing the barriers, the regional connectivity had been significantly improved, with the highest extent of 54.9%. The priority areas of ecological restoration were classified into three levels according to the value of cumulative current, namely, the high-grade area, the middle-grade area and the low-grade area. The high-grade area covered 4.3 km2 of barriers, mainly distributed in the southwest of Zhengxiang District, northeast and south central of Zhuhui District. The middle-grade area was dominated by pinch area and ecological source area with centrality less than 100, covering an area of about 12.9 km2, mainly distributed in the central part of Zhengxiang District, northeast and south central of Zhuhui District. The low-level area was mainly distributed in south central of Zhuhui District, with 51.8 km2 of residual ecological sources. By coupling InVEST habitat quality analysis module and circuit theory, the ecological security pattern for biological protection was constructed, which provides scientific reference for biological protection.
Subject(s)
Conservation of Natural Resources , Ecosystem , China , Cities , Ecology , ForestsABSTRACT
Green space ecological network is important for improving the fragmentation of regional ecological space, biodiversity loss, imbalance of supply and demand in ecosystem services, and ensuring regional ecology. With Dongting Lake region as an example, the ecological sources were evaluated and identified, and basic ecological resistance of grid element was calculated from the perspectives of comprehensive ecosystem service function evaluation, potential biodiversity comprehensive index evaluation and morphological spatial pattern analysis with the support of 3S technology. We corrected the basic ecological resistance by night light index, used the minimum cumulative resistance model to identify ecological corridors, and constructed a weighted evaluation model, eva-luated the degree of aggregation and dispersion of the sources, as well as the contribution of ecological connection of the corridors. Furthermore, we compared and evaluated the structural characteristic index of the integrated networks, the potential "source sink" networks and the planning networks. The results showed that the spatial distribution of the sources was uneven, with forest land, shrubland and wetland acounting for 95.9% of the total area. The Dongting Lake wetland located in the middle of the region was at high ecological risk. The closer the source was to the center of the ecological network system and the smaller the average minimum cumulative resistance was to other sources, the stronger the advantages of aggregation and dispersion. The denser the distribution of medium and high ecological quality sources was around the high ecological quality sources, the higher the aggregation and dispersion. The closer the corridor was to the high ecological quality sources, the greater contribution of ecological connection. Forest land, shrubland, especially river played an important role in connecting natural ecosystem and human social system. The "source-sink" planning greenways formed a supplement to the "source-sink" potential ecological corridors. Compared with the "source-sink" potential network, the α, ß, γ and ρ index of the integrated network was increased by 123.1%, 25.8%, 26.2% and 74.6% respectively. Compared with the "source-sink" planning network, the α, ß, γ and ρ index was increased by 190.0%, 31.1%, 32.5% and 114.6% respectively. The results could provide reference for the construction of green space ecological network and planning of land use in Dongting Lake region.
Subject(s)
Conservation of Natural Resources , Ecosystem , Biodiversity , China , Ecology , Humans , Lakes , Parks, RecreationalABSTRACT
With the technology of geographic information system (GIS), the ecosystem service va-lue (ESV) coefficient of different types of land use in Dongting Lake area was estimated in this paper by interpreting the remote-sensing image for years and combining its economic development statistics. Meanwhile, the temporal-spatial evolvement characteristics of the ESV were investigated by employing the methods of spatial statistics analysis such as spatial autocorrelation, highland clustering analysis and hotspot analysis. The results showed that the ESV of Dongting Lake area increased slightly during 2000-2013, from 3868.39 billion yuan to 3886.62 billion yuan due to the increase of wetland in the area. The areas with high ESV and low ESV were infiltrated into each other, while the areas with second high ESV embraced those areas with high and low ESV. The characteristics of ESV and its dynamic evolvement in Dongting Lake area were obviously of spatial autocorrelation and high and low value clustering, but the trend was weakened. The focus of ESV hotspot of Dongting Lake area moved to northwest slightly with a "S" track in a obviously phased manner of "quick-slow-quick".
