Study On Construction Of Ecological Rehabilitation System In Aquatic-terrestrial Ecotone, Lijiang River

The ecological and environmental problems of the degradation in Lijiang river had significantly increased with the rapid development of industry, agriculture and tourism in the past few years. For example, increases of seasonal flooding and dry events, decreases of runoff and water quality and then importment decline in scenic beauty degree and tourist capacity. According to current situation of aquatic-terrestrial ecotone in the Lijiang river, this paper carried out the ecological problem diagnosis and the ecosystem health evaluation of Lijiang river aquatic-terrestrial ecotone, furtherly constructed ecological rehabilitation system, raised the key technology and ecological management strategies. The results of our study could provide important insight into the practices of ecological function restoration and the sustainable development of high quality of tourism landscape. The main findings of this research are as follows:(1) We used the method of landscape ecology and the theory of geomorphology, ecology, system science to determine the landscape pattern and human disturbance level of Lijiang river aquatic-terrestrial ecotone. The result indicate that Lijiang river amphibious staggered over 70%in mild degradation degree above with ecological system. The reverse succession caused by human interference account for this degradation in the aquatic-terrestrial ecotone of Lijiang river. The influence of tourism disturbance on vegetation coverage is also obvious, and furtherly impact on the ecological system of water and land. Through the genetic analysis of interference, grade division standard and the extent of degradation analysis, the assessments of ecological service function and ecological health. We found that the dominant ecological function was biodiversity aquatic-terrestrial ecotone of Lijiang river, it has generally in a state of sub health.(2) Based on the analysis of characteristics of typical flood land micro structure of landscape space, we used the methods of ecology and modern mathematical statistics to assess the interference effects on plant research. The results show that flood land vegetation spatial present typical zonal distribution. It was significantly characterized of the transitional pattern from gravel beaches to bringing to opening the amphibious, strong human disturbance cause regional vegetation degradation.(3) On the basis of the combination of the field investigations and the laboratory simulation experiments, we found that water logging stress affect plant growth, Half submerged of Iris pseudacorus L, Cynodondactylon (Linn.)Pers., Polygonum hydropiper, Humulus scandens (Lour.) Merr, Artemisia argyi, Conyza canadensis, Phragmites australis (Cav.) Trin. ex Steud, Alternanthera philoxeroides Griseb. grow the most favourable, which can be used as grass of the aquatic-terrestrial ecotone of Lijiang river. Based on plant selection experiments, Substrate screening test shows that Artemisia argyi, Aster tataricus L.f., Humulus scandens (Lour.) Merr, Alternanthera philoxeroides Griseb., Geum aleppicum Jacq., Pterocarya stenoptera are best for large particle matrix resistance, ratio of gravel and soil according to the mass ratio of 1:9 can achieve good recovery effect. In this case peat and other animal manure could help plant germination and growth, and animal manure is better than peat, while aggregate agent has no significant effect on plant growth. Ecological remediation experiments show that Flueggea suffruticosa (pall.) Baill and Alternanthera philoxeroides Griseb. have high ecological recovery in gravel beaches.(4) We divided the aquatic-terrestrial ecotone of Lijiang river into four type groups including slope, terrace, beaches, central bar and 21 site types. The main factors were slope, rock ratio, vegetation, soil organic matter. This paper totally proposed 6 staggered system (24 patterns) for ecosystem rehabilitation in aquatic-terrestrial ecotone of Lijiang river including slope protection system, terrace door system, gravel flood protection system, riverbank protection system, ten gallery door system, town area protection system. According to the degradation degree and health status, the strategies of the ecological restoration in this aquatic-terrestrial ecotone can be divided into construction, repair, gather and protected types. The corresponding ecological rehabilitation technology include species breeding, plant mosaic technology, ecosystem regulation technology, matrix repair technology, engineering, green technology, the fast greening technology, management technology amount to 7 categories of 26 kinds. Finally, We established model of rehabilitation technology of the typical flood land ecosystem.(5) On the basis of ecological degradation mechanism diagnosis and the ecosystem health evaluation, we discussed the environmental characteristics, tourism development requirements, restoration of the ecological function of the aquatic-terrestrial ecotone of Lijiang river and proposed some human intervention based ecological management measures in aquatic-terrestrial ecotone ecological system, which include ecological protection and restoration measures, ecological planning, development and management, tourism pattern, ecological protection consciousness. We should take integrated ecosystem management measure to restore ecosystem in DAXU.