| The stability of the Forest system plays a significant role in its healthy and sus-tainable development.But how to evaluate it has been a long-term research difficult point,especially for the research of large forest.A unified and systematic method has not been found by now.The West Dongting Lake region as the research object,from the level of forest landscape and based on the theory of complicated system,this research mainly evalu-ated and analyzed the stability of weighted forest landscape patches coupling network using the method of structural entropy,and also puts forward some measures to optimize the stability of the weighted forest landscape patch coupling network structure,which provides a new idea for the healthy,stable and sustainable management of forest.Fol-lowing are the main research contents and results:(1)This research,regarding the location of the nodes in the weighted forest land-scape patches coupling network,combined with its own unique properties,built the importance assessment method which is based on the number of points and the intensity of the nodes.Besides,based on this,the structural entropy based on the importance of nodes to achieve the fast and accurate assessment of the stability of the weighted forest landscape patches coupling network is constructed.In order to study the influence of the network size and the degree distribution of the forest landscape patches on the stability of the forest network structure,40 networks were selected and divided into A and B groups(20 networks).According to the follow-up study,It is found that the importance of some nodes in all the networks shows a negative value,and it is also reflecting the irrationality of the structure of the forest landscape patch coupling network in the natural state which needs timely adjustment.(2)The influence of the number of nodes on the stability of group A is studied.According to the entropy of the network structure of group A,the order of the structure entropy is from 3.4884、3.8622、4.1303、4.5779、4.7668、4.9646、4.9844、5.1061、5.5131、5.6805、5.7354、5.7754、5.9142、6.0345、6.1036、6.4261、6.5478、6.6261、6.5844、6.7513.The results show that the structural entropy increases with the increase of the network size.Through the regression analysis of the number of nodes and the structure entropy.The results show that with the increase of the number of nodes,the growth rate of network structure entropy is gradually slowed down.(3)Group B is selected to study the influence of the distribution of the research degree on the forest network stability.In order to avoid the influence of the number of nodes on the stability of the network,the structural entropy of the original network is standardized.Through regression analysis of degree distribution and standard structure entropy.The results show that the entropy of the standard structure is positively corre-lated with the degree distribution,and the growth rate of the standard structure entropy decreases with the increase of the degree distribution.(4)According to the influence of network size and degree distribution on the sta-bility of weighted forest landscape patches coupling network,there kinds of methods are used to simulate and optimize three kinds of weighted forest landscape patches cou-pling network.They are respectively to increase the number of edge nodes,to re-divide the large patches within the coupling body and to reduce the "bridge" nodes:Through comparative analysis.The first method makes the entropy of the network structure in-crease from 1.9465 to 2.1353,which is 9.70%higher.The second method increases the structure entropy of the network structure from 0.7876 to 0.7918,and improves the structure entropy of the network structure by 0.53%;the third way makes the network structure entropy increase from 0.4528 to 0.7598,an increase of 67.82%.The results show that three methods both can effectively improve the stability of the weighted for-est landscape patch coupling network. |
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