The construction and optimization of ecological networks based on natural heritage sites in Jiangsu Province

Abstract

Natural heritage sites are important habitats for fauna and flora, and assist in maintaining ecosystem service functions. Often however, human activities and natural threats have damaged the integrity of such sites, and large habitats have become increasingly fragmented. As a result, regional biodiversity conservation has been seriously threatened. To change this situation, ecological networks are being considered as an effective way to re-connect important natural heritage sites. Within a rational ecological network, the flow of material, energy and information among various areas can be ensured and the quality of natural ecosystems can be improved. The effective setting up of ecological corridors and connecting fragmented habitats are crucial actions in the protection of the biodiversity of natural heritage sites, and in the maintenance of regional ecological security. This is especially true in rapidly urbanizing areas: taking natural heritage sites as the core of an ecological network, constructing these networks and undertaking research on ecological values are particularly important actions in this type of developing area. Jiangsu province is located in the coastal area of eastern China where land resources are limited, and has a high population density and a well-developed economy. Human activities have however disturbed the ecological balance seriously, so there is a need to implement regional ecological networks, to integrate natural heritage resources, and to promote the sustainable development of regional ecosystems. For the present study, natural heritage core-areas were firstly selected based on the theory and principles of Landscape Ecology and Conservation Biology, and the different cost values of different landscape types decided with the help of GIS technology. Second, taking Jiangsu Province as an example allowed quantitative simulation of the establishment of natural heritage sites for potential ecological networks using a minimum cumulative resistance model, and the analysis of network connectivity using an integral index of connectivity and probability of connectivity. Third, the main natural heritage corridors in Jiangsu Province were studied, which allowed the determination of suitable optimization measures on the basis of the current corridors. The results show that, in Jiangsu Province, about 78.28% of the forested area, 88.70% of the beach area, and 94.37% of the grassed area together make up the major part of the natural heritage ecological network. These ecological cores have great influence on the establishment of ecological networks. The study also found that the habitats with larger area and greater length have a higher degree of importance in maintaining landscape connectivity. However, the current integral index of connectivity of the study area ranges between 0.001 and 0.003, which indicates poor connectivity. These values would increase to between 0.044 and 0.046, and the possibility of connectivity could go as high as 0.074, if the construction of the proposed ecological networks were achieved. The increment of these values indicates that the construction of natural heritage ecological corridors improves the level of landscape connectivity significantly. Based on the existing ecological network structure, increasing connections between fragmented ecological sites is thus a feasible strategy to optimize the overall ecological network system. Lastly, suggestions on how to achieve optimization of the ecological network are put forward. Overall, the results in this paper provide an important reference point for the sustainable development of natural heritage and biodiversity protection, and also provide useful information for the implementation of natural heritage protection measures.