Recently, developments in coastal areas severely destroyed mangrove forests and resulted in biodiversity decrease in coastal wetlands. Therefore, great importance was attached to mangrove restoration to protect biodiversity in coastal wetlands. Biodiversity restoration should become an important goal of mangrove replanting. In this paper, in terms of biodiversity restoration of mangrove frola and benthic fauna, main problems in mangrove restoration in China were analyzed and some basic research strategies were brought forward.
For mangrove plant diversity restoration, most viviparous species were used in mangrove restoration because their propagules germinate before they leave mother trees and they can be directly used in afforestation in coastal beaches. However, few non-viviparous species were used in mangrove restoration because their mature propagules germinate after they leave mother trees and it is difficult in direct plantation in coastal beaches. In China, although non-viviparous species make up 60 percent of the total mangrove plant species, mangrove restoration was focused on viviparous species. To improve mangrove plant diversity, some researches should be enhanced as follows. Firstly, germination traits of non-viviparous mangrove species should be studied. Only after types, processes and ecological conditions of seed dormancy are correctly realized, high successfulness can be insured in nursery of non-viviparous species and enough seedlings can be provided for mangrove restoration. Secondly, eco-physiological researches should be also enhanced to provide important basis on mangrove biodiversity restoration. Thirdly, more researches on allelopathy between mangrove species should be carried out to give theoretic basis on better mangrove restoration performance.
Mangrove restoration was settled only on vegetation restoration and much attention was paid to nursery techniques and area selection for afforestation. However, restoration of ecosystem functions was not considered as a goal in mangrove restoration, especially the function of mangrove vegetation to maintain other subsystems such as benthic fauna. In terms of faunal diversity, it is still “non-directional” for mangrove restoration. Therefore, it is necessary to study the effects of vegetation restoration methods on benthic faunal diversity, in order not to make other subsystems’ reconstruction blind and uncertain after vegetation restoration. Effects of mangrove plant species on benthic faunal diversity restoration should be thoroughly studied. Through field controlled trials and laboratory simulated experiments, differences in benthic animal species and quantities under mangroves with different dominant species should be studied to explore the differences in feeding preferences of main benthic animals to mangrove leaves including food selectivity and animal-plant nutritive relation, from which the relationships between remediation of benthic faunal subsystems and mangrove planting species can be realized. Differences in benthic animal species and quantities under mangroves with different planting densities should be also studied to obtain the relationships between remediation of benthic faunal subsystems and mangrove planting density. Meanwhile, through analyses of sediment, mangrove biomass and litter falls, reconstruction of mangrove vegetation to sediments should be studied to explore the relationships between ecological remediation of benthic faunal subsystems and changes in sedimental physical-chemical characteristics during mangrove restoration processes.