北方滨海人工湿地水生生物群落快速重建目标及适宜物种清单确定——以天津临港二期湿地为例

Determination of biological community reconstruction targets and suitable species list for constructed wetland in north China coastal area: a case study of Tianjin Lingang Constructed Wetland (Phase Ⅱ)

由于滨海湿地的萎缩和退化对全球鸟类迁徙构成了严重威胁,开展自然湿地或人工构建湿地生态恢复已经成为滨海湿地保护与研究的重要内容。以天津临港二期湿地为例,研究北方滨海人工湿地生物群落快速重建目标及适宜物种清单的确定方法。临港二期湿地2019年共检出浮游植物110种、浮游动物28种,而大型底栖动物仅1种,鱼类未检出,水体生物种类结构单一,难以为迁徙侯鸟提供充足食源。选择与临港二期湿地相同(近)区域、同盐度水平的北大港湿地自然保护区以及临港一期湿地作为备选参照湿地(参考湿地)进行同步生物多样性调查分析,结果表明,北大港水库东区、北大港水库西区、临港一期湿地具有较好的浮游动植物、底栖动物多样性及鱼类资源,可以作为临港二期湿地修复的参照湿地。与参照湿地相比,临港二期湿地具有较好的浮游植物生物多样性,应重点恢复底栖动物与鱼类群落,考虑到后期鱼类恢复后的食物需求,可同步进行浮游动物的增殖放流。以参照湿地生物多样性调查结果与文献资料数据为依据,确定临港二期湿地底栖动物生态恢复目标为:Shannon-Wiener生物多样性指数远期(10年)达到3.00,近期(5年)达到1.58;生物密度远期(10年)恢复至600个/m^(2),近期(5年)恢复至300个/m^(2);同时确定了临港湿地生物群落快速重建的底栖动物清单(15种)与鱼类清单(14种),并提出了临港二期湿地生态系统恢复的食物网构建路线图。研究结果表明,选择同区域、类似的天然湿地作为参考湿地,通过生物调查与生物多样性比选,确定具体参照湿地,并依据参照湿地生态特征确定待修复湿地的生物群落快速重建目标与适宜物种清单,是合理可行的。

As the shrinkage and degradation of coastal wetlands pose a serious threat to global bird migration, restoration of the degraded or constructed wetlands has become an important content for the coastal wetland protection. Tianjin Lingang Constructed Wetland(Phase Ⅱ), a typical coastal constructed wetland in north China, was taken as a case study for the restoration strategy of constructed wetlands, with respect to methods for determining biological community rapid reconstruction targets and suitable community species list. The other adjacent Beidagang Wetland Nature Reserve and Lingang Constructed Wetland(Phase Ⅰ), with similar salinity as Lingang Constructed Wetland(Phase Ⅱ), were selected as alternative reference wetlands. The results of field investigation in 2019 showed that there were 110 species of phytoplankton and 28 species of zooplankton with only one species of macro-zoobenthos, while no fish were found in Lingang Constructed Wetland(Phase Ⅱ). It was indicated that aquatic organism species structure was too simple to afford adequate food supply for migratory birds. The investigation results also showed that East District of Beidagang Reservoir, West District of Beidagang Reservoir, and Lingang Constructed wetland(Phase Ⅰ) had a higher biodiversity of phytoplankton, zoobenthos and fish than those in Lingang Constructed Wetland(Phase Ⅱ), and they could serve as the reference wetland. Since Lingang Constructed Wetland(Phase Ⅱ) has a not bad diversity of phytoplankton, only zoobenthos and fish resource need to be restored. Taking into account the food needs of the fish after recovery, the zooplankton can be released simultaneously. Based on the investigation & literature data of the reference wetland, zoobenthos restoration targets were determined as follows. Shannon-Wiener index will reach 1.58 in the coming 5 years and 3.00 in 10 years. The biological density will be increased to 300 ind./m2 in the coming 5 years and 600 ind./m2 in 10 years. Meanwhile, restoration species list for biological community rapid reconstruction, including 15 species of zoobenthos and 14 species of fish, was recommended and the roadmap for food chain reconstruction was also put forward. Our results suggest that, in terms of restoration of a degraded or constructed wetland in coastal area, natural wetlands with similar characteristics in the same or adjacent area can be selected as alternative reference wetlands, and biological survey & biodiversity comparison are helpful for the determination of reference wetland. Once the reference wetland was determined, the targets, and the suitable species for rapid reconstruction of the biological community could be proposed with the comparison between the reference wetlands and target wetlands.