Habitat Degradation Diagnosis And Preliminary Study On The Relationship Between Ecosystem Structure And Functions Of Bay

In recent years, under the double impacts of natural variations and human activities, significant degradation has appeared in the global marine ecosystem, which is particularly prominent in bays where ecological environment is fragile and significantly affected by human activities. Accurate diagnosis on the degree of habitat degradation is the foundation and prerequisite of ecosystem restoration and reconstruction. Causes of habitat degradation in the enclosed bay are complex and diverse, and mature diagnostic technology systems and methods of habitat degradation need to be addressed.In addition, habitat degradation belongs to the category of the degradation of ecosystem structure; degradation of the entire ecosystem also includes degradation of functions and more complex change in the relationship between structure and functions. Therefore, an accurate understanding of marine ecosystem evolution, involves not only establishment of the appropriate habitat degradation diagnostic system, but also further study on characteristics and mechanisms of variation of the relationship between structure and functions.1 Habitat Degradation Diagnosis of the enclosed bayBased on the concept model -- "DPSIR", an integrated multi-channel diagnostic method is taken to construct a diagnostic model for enclosed bay habitat degradation. Example analysis is carried out in Sansha Bay, Fujian, diagnosing habitat degradation status during two sub-periods (1991-2006 and 2006-2012) and screening the main controlling factors of habitat degradation. The results are as follows:(1)In 1991, Sansha Bay was in a non-degraded state before large-scale development and its habitat quality was in excellent condition. The habitat quality of Sansha Bay decreased to average condition in 2006, two-level lower than in 1991. In 2012, the habitat quality of Sansha Bay retained at average condition. The major controlling factors for causing habitat degradation vary in different periods, i.e., DIN,DIP, and GDP per capita in 1991-2006; and DIN, DIP, and COD in 2006-2012.(2) The habitat degradation experienced significant spatial variations among six sub-bays and the degradation trend in growing scale shows a more significant correlation with the distribution of local leading industries along shorelines. From this perspective, the scale of development of leading industries should be effectively controlled to obtain economic, social and environmental benefits at the same time.(3) Hydrodynamic conditions, sediment characteristics, and aquaculture methods were recognized as the underlying causes of spatial heterogeneity in the distribution of nitrogen and phosphorous pollutants, the two major controlling factors of habitat degradation in the bay area. In order to achieve the goal of balancing nutrient inputs and outputs in Sansha Bay, a feasible and practical zone restoration strategy was developed for reasonable adjustment and arrangement of aquaculture species and production scale in accordance with varying hydrodynamic conditions and sediment characteristics in six sub-bay areas (sub-systems). The proposed zone restoration strategy lays a solid foundation for habitat restoration and management in Sansha Bay.2 Study on the Relationship between Ecosystem Structure and Functions of BayIn this paper, Ecosystem Structure-Function Relationship evaluation model was established, introducing the concept of ecosystem coordination, quantifying interactions of internal systems, to understand long-term variation characteristics of the relationship quantitatively and connection with ecosystem health. Earlier research has been carried out in Jiaozhou Bay, Shandong, accumulating long-term, continuous marine survey data and research results. Based on data of each year from 1997 to 2009, Jiaozhou Bay was treated as an analytic example in this study. The results are as follows:(1) Jiaozhou Bay ecosystem was in the sub-health status from 1997 to 2009, except for the years of 2007 and 2008, during which time the status was unhealthy (health index were 0.34 and 0.30, respectively). Biont and habitat structure, support, provision, regulating and cultural services went through different degrees of degradation, causing the decrease of coordination between structure and services andsynergistically augmenting the deterioration. Index of degradation and coordination was significantly associated.(2) Local climate change influence and human interference on bay ecosystem was considered as the external driving force, quantified with the correlation method. The results showed that before 2000, degree of association between Bay ECI and climatic condition was higher than degree of association between Bay ECI and socio-economic condition; after 2000, socio-economic condition more easily led to ECI change.(3) Contributions of biont structure, habitat structure, support service, provision service, regulating and cultural services to ECI were quantified. As the conclusion, habitat structure and cultural service played promoting roles; regulating service showed no obvious effect; biont structure, support and provision services had been detrimental to the coordination, on which more control and management need to be focused.