Ecosystem Health Assessment Of Jiulong River Estuary

Estuary is a partially closed coastwise bay where seawater and freshwater mix. Two types of ecosystem pool at the estuary. Estuary is influenced by both nature and human. As the world population and economy greatly increase, the relationship between estuary and human is more and more closely. The estuary ecosystem has important value, as it provides abundant products and services to human. At the same time, estuary is easily destroyed by human activities. Some problems such as pollution, siltation, eutrophication, resources exhaustion, et al become increasingly seriously. As a result, the study on estuary has attracted more and more attention.At present, the research on ecosystem health is not mature yet. There are no integraty ecosystem health assessment indicator systems or assessment methods, especially on estuary ecosystem health assessment. This paper took Jiulong River Estuary in Fujian as an example, established a framework of indicators based on PSR Model, and attempted to assess Jiulong River Estuary Ecosystem Health. Then several proposals were offered according in order to the result to improve the status of the estuary.This paper was devided two parts: theoretical research and case study, principally as follows:(1) Theoretical research part included 1^st and 2^nd chapter. In this part, the concept of ecosystem health, its research progress, estuary ecosystem health and the methods of its assessment were introduced. As outlined in Charpter 1, Estuary Ecosystem Health could be defined that: a healthy estuary ecosystem should be balanced and sustainable. Facing natural and human disturbance, on one hand, it can maintain its own ability and state of sustainment, and maintain the balance of matter and energy stream. On the other hand, it can fill the reasonable need of human and the need of sustainable development (port, fishery, entertainment, et al), and doesn't threaten other ecosystems around (sea ecosystem, land ecosystem, valley ecosystem, et al). In this part, Pressure-State-Response (PSR) Model and its application research were introduced. Then the objectives, contents and approach were described. The indicator system of Estuary Ecosystem Health Assessment based on PSR Model was established, including the methods of pressure, state and response.(2) The case study part took Jiulong River Estuary as an example, and included 3^rd to 6^th charpter. In this part, the general situation of Jiulong River Estuary Ecosystem was introduced firstly. The natural environment, social economic features and utilization of the resources were described then. Based on the indicator system established in the theoretical part, Jiulong River Ecosystem Health Assessment 3-class indicator system was built. The qualitative and quantitative analysis approaches were carried out based on the indicator system above. And the current data contrasted with the history data of 1980s clearly. The result indicated that, the major pressures of Jiulong River Estuary were typhoon, soil erosion, biological invasion, red dide, sea-level rise, the increase of population and influent contamination, economic development, and resource exploitation and utilization. The result of quantitative analysis indicated that, the index of abiological environgment state of Jiulong River Ecosystem was 0.38, presenting unhealthy; the index of biological environment state was 0.58, presenting subhealthy; and the final result of Jiulong River Estuary Ecosystem state was 0.48, presenting subhealthy. The response part mainly included laws and policies, essential establishments, and ecological protection and construction. It indicated that, the deterioration trend of Jiulong River Estuary has not been controlled yet. According to this, countermeasures of Jiulong River Estuary Ecosystem restoration were proposed.(3) The integrated index of Jiulong River Ecosystem health state 0.48 had 0.12 effort space to comparably healthy, but had 0.08 to drop to unhealthy. So the alarm bell was ringing: protecting Jiulong River should not be hesitated. From the point of view of optimism, disadvantages in biological and abiological were relatively concentrative. Thus the departments related could offer proposals pertinently. Otherwise, there was only 0.02 space of the abiological environment to subhealthy state, and 0.02 of biological environment to comparably healthy state. This indicated that as long as right methods were adopted and all people acted without indolence, ecological protection of Jiulong River would make great progress. And the healthy state of Jiulong River Ecosystem would be greatly improved.(4) The innovations of this paper was that, giving the concept of Estuary Ecosystem Health according to the study of ecosystem health and the features of estuary ecosystem; establishing a typical indicator system of Estuary Ecosystem Health Assessment based on PSR Model and applying it to Jiulong River Estuary, the result showing that it had practicability; assessing Jiulong River Ecosystem Health for the first time, giving a reference of decision-making to the departments related and having application values.