海涂围滩养鱼生态系统中藻类种群和生物量的研究

研究了滩涂养鱼生态系统中藻类的种群结构等,结果表明共有7门127种,年平均143.92×106个/L、平均生物量105.60mg/L;藻类种群结构、数量、生物量等存在动态变化;结构上以蓝、绿、硅藻门为主,裸、隐、黄、甲藻门为次要门类,绿藻门的种数最多并且占绝对优势;春季绿、硅藻门的数量和生物量大于蓝藻门,夏季蓝藻门藻数远多于其他藻类,秋季蓝、绿、硅藻门生物量接近;藻类组成与异龙湖接近、生物量较其小,但远超过洞庭湖区高产塘的生物量上限。     

Impact of Great Crested Grebes (Podiceps cristatus L.) on fish ponds

Because Great Crested Grebes (Podiceps cristatus L.) mainly feed on fish, fish-farmers sometimes claim that economic losses are caused by grebes (EIFAC, 1988). Such claims were not based on scientific research.Therefore, a study was carried out to measure the impact of Great Crested Grebes on a fish-farm, managed by the Organization for the Improvement of Inland Fisheries (O.V.B.) in Valkenswaard (The Netherlands) during the period 1986–1988. The O.V.B. provided fish data for each pond including fish density and fresh fish weight for each fish species. The number of grebes was counted at least once a week. Activity patterns, including nocturnal activity, were determined both for the period with and without young. No nocturnal foraging activity was observed. Furthermore, fish biomass consumed per 1000 s foraging time by adult birds and chicks was calculated.In some fish-ponds grebes ate coarse fish, and chicks especially were fed these fish. The average daily fish consumption was 222 g for adults and 108 g for juveniles.Based on available fish data, it can be concluded that grebes consumed fewer fish than the number expected to die, and only marginally influenced the fish populations in the aquaculture ponds studied.     

粤港澳大湾区基塘多功能性尺度效应及生态修复策略

基塘具有生产、生态、社会等多种功能,对保障粤港澳大湾区生态安全和可持续发展具有重要意义,当前学界对基塘多功能性的尺度效应关注尚不足。应用土地利用变化分析、田野调查、半结构访谈等方法,构建了基塘多功能性的尺度分析框架。研究表明：（1）以桑（蔗）基鱼塘为主的基塘发展阶段,基塘生产、生态、社会功能发展均衡,塘基之间,基塘与村落、区域生产生活形成良性循环,孕育了与村落、区域聚落、产业、社会相融合的基塘文化;（2）以单一化养殖为主的基塘发展阶段,村集体和农户作为基塘生产功能的直接受益者,片面追求经济效益最大化导致基塘生态功能的弱化;（3）基塘多功能性的协调发展有赖于不同制度层级的联动协作,通过创新基塘的土地经营模式,协调各个制度层级与以农户为主的基塘经营主体的利益关系,是实现基塘多功能化发展的关键。研究结果对制定分级农业生态系统管理措施、粤港澳大湾区国土空间管制与生态修复均具有启示意义。