The Disturbance Mechanism and Potential Ecological Loss of the Barringtonia racemosa Community on the East Coast of Leizhou Peninsula

With the methods of sample square investigation, comparative analysis of remote sensing images and estimation of ecosystem service value, the mechanism of human and natural disturbance of the Barringtonia racemosa community was studied. The effects of different disturbance factors on the two scales, i.e., the spatial pattern of the Barringtonia racemosa community and the individual plants, were described. Based on an estimation of the ecosystem service function and value, the potential ecological loss caused by disturbance of the Barringtonia racemosa community was calculated. The results showed that the Barringtonia racemosa community in the mangrove wetland of Leizhou Peninsula was mainly affected by plant invasion, river diversion and diseases and pests. The invasion of Mikania micrantha was the most serious and the influence caused by Chromolaena odorata was in the second place. Plant invasion showed distinctive vertical differences among the herb, shrub and high forest layers of the Barringtonia racemosa community. The population density of Barringtonia racemosa decreased and landscape pattern of community tended to be broken due to being mechanically scoured by water on concave and convex river banks. As for diseases and pests, it was Pseudaulacaspis cockerelli that mainly inhibited the growth of the lower layer of Barringtonia racemosa. The degree of damage in Barringtonia racemosa community was mainly affected by the spatial level of the plant. These three kinds of disturbance have impacts on the ecological functions, such as water purification, carbon sequestration, oxygen production, climate regulation, pollutant degradation and biodiversity, resulting in the potential ecological loss of Barringtonia racemosa community up to 249 thousand RMB Yuan per year. Some suggestions of ecological protection, such as physical control, community reformation and ecological protection red line setting, are put forward, drawing on the concept of "prevention is more important than treatment", to effectively prevent and control the damage of various types of disturbance of the Barringtonia racemosa community.