【作者】 贾亦飞；

【导师】 雷光春；

【作者基本信息】 北京林业大学 ， 自然保护区学， 2013， 博士

【摘要】 水文过程及其对湿地功能影响的研究一直是湿地生态学研究的核心内容之一,对于理解湿地生态过程、生态系统组分和生态系统服务具有重要意义。鄱阳湖是我国最重要的迁徙水鸟越冬地,至少有14种濒危越冬水鸟在此越冬,并有27种以上的越冬水鸟超过其全球种群的1%,其中极危物种白鹤在此越冬的数量达到其全球种群数量的98%以上。三峡大坝的运行对下游河道及通江湖泊湿地生态系统产生了重大影响,引起了国内外各界的高度重视。关注的核心问题是水位变化对候鸟栖息地的影响。因此,正确认识水位变化对湿地及越冬候鸟的影响,以及越冬候鸟对环境变化的响应是鄱阳湖湿地保护迫切需要解决的关键科学问题。本文通过收集和整理1998-2013年鄱阳湖环湖鸟类调查数据,选择鄱阳湖栖息地、植被和水鸟特征等参数,建立了鄱阳湖水位-栖息地-越冬水鸟关系的耦合模型；并通过2010-2013年间对越冬候鸟的野外观察、对其食物资源的样方调查与样品分析、运用模型模拟分析等手段,揭示白鹤及其他越冬水鸟对鄱阳湖水位波动的响应,得到了以下主要结果：(1)不同的水位波动范围,对不同的越冬水鸟栖息地及其食物资源有不同的影响。维持鄱阳湖水鸟栖息地的冬季水位下限为8.2-8.8m(吴淞高程,下同),夏季的最高水位不能高于17.4m。鄱阳湖越冬水鸟五个不同取食集团(取食茎块组、取食草组、取食种子组、取食无脊椎动物组和取食鱼类组)的最优冬季水位下限分别为：>8.5m;>8.3m;7.2-8.4m;<8.8m;<8.4m,夏季最高水位分别为：-；-；<17.6m；<17.4m；<17.4m,其中最高水位对第一和第二集团没有影响。鄱阳湖的旗舰物种白鹤的最优水位在冬季为8.7-10.2m之间,夏季水位不能高于19.5m。影响五个取食集团水位的不同的原因并不一致。(2)以1983-2012年鄱阳湖国家级保护区白鹤越冬种群数据以及相对应的环境数据,建立了鄱阳湖白鹤的空间状态(SSM)模型,得出了全球白鹤东部种群近30年的种群增长率为4.08%,从1983-1984越冬季的840只到2011-2012年越冬季4315只,平均为2134±827(平均值±标准差)只。(3)不利的水位会显著降低白鹤食物资源苦草茎块密度。2011年1月调查到蚌湖和大湖池苦草冬芽密度分别为1.24个/m2和0.17个/m2。2011年5月和2012年5月调查苦草幼苗和芽的平均密度分别为18.2±13.6个和38.6±38.8个,两年密度显著不同(p<0.001)(4)本文首次报道了2010-2011年越冬季白鹤大规模上草洲觅食的现象。白鹤在鄱阳湖通常在浅水湖泊和泥滩中以苦草冬芽为主要食物。2010年冬,苦草冬芽资源短缺,白鹤从浅水湖泊和泥滩地转移至浅水湖泊间的苔草草洲取食下江委陵菜的直根,白鹤越冬行为与其在浅水湖泊中呈差异显著(p=0.008),其中觅食时间较在浅水湖泊里显著缩短(p<0.001),但是警戒行为显著增加(p<0.001)。而水位正常的2011年,并且没有大规模上草洲觅食的现象。白鹤主要食物苦草冬芽、老鸦瓣和下江委陵菜。对这三种食物资源各种营养成分分析表明,三者营养成分差异显著(p<0.001),但是营养物质的多少并不是白鹤取食的首要原因。白鹤在正常年份会选择最优栖息地栖息并取食苦草茎块,仅仅在苦草资源短缺情况下,才会改变其栖息地和食性来度过难关。本研究建议的高水位时期和低水位时期的最优水位是对白鹤及鄱阳湖水鸟群落的保护具有重要意义。广义加性模型的结果显示无论是低水位时期还是高水位时期,高的水位都可能对种群产生消极影响。长江水位和鄱阳湖支流水位之间的动态平衡是影响鄱阳湖水位波动的主要驱动力,尤其是在三峡大坝运行后江湖关系的变化,会对鄱阳湖越冬水鸟生存产生潜在的威胁。本研究的发现对拟修建的鄱阳湖水利枢纽工程,以及整个流域尺度上的大坝水位调度具有重要的参考价值。同时,还揭示了白鹤在不利环境下具有主动适应的能力,但是适应新的栖息地对于白鹤并非最佳选择,一旦条件改善白鹤会选择其最优栖息地进行觅食。本文的创新点为首次应用定量化数据来分析鄱阳湖水鸟与水位波动的关系,并且分别得出鄱阳湖不同取食集团和旗舰物种白鹤在夏季和冬季的水位需求,同时验证得到白鹤栖息地选择是符合最优觅食理论的。更多还原

【Abstract】 Hydrologic process and its impact on wetland has always been one of the hot issues in ecological studies, which is crucial for understanding the relationship between ecological processes, ecological components and ecosystem services. Poyang Lake is one of the most important wintering grounds for migrating waterbirds in China. Over14endangered waterbird species wintering there. In addition, wintering population of27waterbird species exceeds1%of their global populations, amongst which, more than98%of the Critically Endangered Siberian cranes’(Grus leucogeranus) global population wintering here. Since the operation of the Three Gorges Dam, downstream rivers and lakes have been significantly affected, which become a great concern from conservation societies. The key issue concerned is the impact of water level on migrating birds and their habitats. Thus, assessing the impacts of water level on wintering birds and their adaptability to environmental changes are the most urgent task for Poyang Lake wetland protection. This dissertation collected and reviewed bird census data in the Poyang Lake area from1998to2013,identified key ecological characters of the Poyang Lake wetlands, vegetation and waterbirds, and established a coupling model that can project the relationship between water level, habitat and wintering waterbirds. Further studies focus on impact of water level fluctuation on food resources of the birds, and the responses of the birds to the environmental change, in particular, the Siberian cranes. The study revealed following findings:1. Water level fluctuation scale defines differentiated impacts on various habitats and food resources. For all water bird groups, the lowest accept water level range for waterbirds is between8.2and8.8m above sea level in winter, whereas the highest accept water level in summer17.4m above sea level. The lower limit water levels for the five foraging bird groups (Tuber feeders, Sedge foragers, Seed eaters, Invertebrate eaters and Fish eaters) in winter are>8.5m;>8.3m;7.2-8.4m;<8.8m;<8.4m respectively, and in summer are-;-;<17.6m;<17.4m; and<17.4m, respectively. The highest water level does not affect the first and the second diet group. For Siberian cranes, the optimal water level is between8.7-10.2m in winter and no higher than19.5m in summer.2. Based on the1983-2012population data of the wintering Siberian cranes in the Poyang Lake National Nature Reserve and related environmental data, this study builds a GAM model for Siberian cranes and revealed that the population growth rate for Siberian cranes has been4.08%per year over the past30years, with the total population grows from840in the1983-1984winter, to4315in the2011-2012winter.3. Adverse water level may significantly reduce the tuber density of V. spiralis that Siberian cranes mainly forage on. The tuber density of V. spiralis at Benghu Lake and Dahuchi Lake was1.24per m2and0.17per m2in Jan.,2011. The numbers of V. spiralis seedlings and sprouts was18.2±13.6and38.6±38.8, May2011and May2012, which was significantly difference in the two years (p<0.001). The nutrition contained in the tuber of V. spiralis, main root of P. limprichtii and Amana edulis that Siberian cranes foraged on varies considerably, but nutrition had no significant impact on the food choice for Siberian cranes.4. In2010, due to extreme low density of V. spiralis tubers, Siberian cranes shifted their habitat from shallow water area to grassland, and were found to feed the roots of P. limprichtii instead of V. spiralis tubers. Observation shown their overwintering behaviors changed significantly (p=0.008), compared to their behaviors in shallow water, where they normally forage. Their foraging time is shorter (p=0.00), while the alerting time is significantly increased (p=0.00). In2011, when water level fluctuate within the normal range, almost all Siberian cranes foraged at their normal habitat (shallow water and mudflats) spend more time foraging and less alerting on mudflats. This indicates that Siberian cranes choose the optimal habitats in normal years and survive bad conditions by changing their habits, which conforms to the Optimal Foraging theory.The upper and lower water level limits for the waterbirds suggested in this dissertation are important for the protection of Siberian cranes and other waterbird species. The GAM Model result shows that extreme high water level has significant negative impact on populations. The water levels of Yangtze River and Poyang Lake Inflow Rivers controls water level of the Poyang Lake. The operation of the Three Gorges Dam forges a potential threat to the wintering birds in this area. This study provided a reference for the proposed Poyang Lake Dam and its operation. The study also demonstrates that Siberian cranes prefer optimal habitats though they are able to adapt themselves to a new environment.In conclusion, this dissertation developed a model that builds on the long-term bird census data to analyze the relationship between water birds and water level in Poyang Lake, and revealed acceptable water levels for five different foraging groups and Siberian cranes in winter and summer, and verifies the optimal foraging theory of Siberian crane’s habitat selection, which advanced our knowledge in the field.更多还原