Biodiversity changes in the lakes of the Central Yangtze

分析了1983-2011年鄱阳湖国家级自然保护区越冬白鹤种群数量的年际变化趋势，检验了白鹤种群动态与繁殖地和越冬地气候变化的相关性，气候变量包括月平均气温、月平均最高气温、月平均最低气温和月降水量。研究结果表明，鄱阳湖国家级自然保护区内的白鹤年最大数量平均为（2 130±153）只，呈显著地线性增长趋势（<em>R</em>²=0.454，<em>F</em>=22.441，d<em>f</em>=28，<em>P</em>=0.000），但年际波动较大。在越冬地，越冬当年10月、11月、12月的气候变量与白鹤种群数量没有显著的相关性，但越冬初期10月份和越冬后期翌年3月份的气温变量与第4年、第5年、第6年及第7年的白鹤种群数量存在显著的正相关，表明越冬地气候对白鹤种群大小的影响存在时滞效应。越冬初期和末期可能是白鹤补充能量的关键阶段，而且越冬初期的气候可能也与冬季食物的数量或质量相关，因此这两个阶段的适宜气温可能有利于个体尤其是幼鹤的存活，使更多的个体参加繁殖，由于白鹤的性成熟年龄在3-5a，因此其对白鹤种群增长的有利影响会在3a以后表现出来。白鹤种群数量变化与繁殖地繁殖期的降水量没有显著的相关性，而与7月份的气温变量存在显著的正相关。多元线性回归分析结果表明，6a前的10月份平均最低温度、2a前的10月最高温度及5a前的10月平均气温是白鹤种群数量变化的显著预测因子，共同解释了鄱阳湖国家级自然保护区白鹤种群数量变化的74.8%（<em>F</em>=23.807，d<em>f</em>=27，<em>P</em>=0.000）。;Siberian crane (<em>Grus leucogeranus</em>) is a critically endangered species and has been a bird species under second class protection. In recent years, almost the entire population winters at or very near Poyang Lake, China. Based on the annual maximum population size of Siberian crane wintering in the Poyang Lake National Nature Reserve during 1983 and 2011, we tested the correlation between population size and the climate variables of its wintering and breeding areas. The climate variables included monthly average air temperature, monthly average maximum air temperature, monthly average minimum air temperature and monthly precipitation. The results showed that the annual maximum population size of Siberian crane in the Poyang Lake National Nature Reserve was 2130±153, with a significant linear increase (<em>R</em>²=0.454, <em>F</em>=22.441, d<em>f</em>=28, <em>P</em>=0.000) and drastic annual fluctuation. The Pearson correlation analysis results indicated that there were no significant correlations between the population size and the climate variables in the same year. However, the air temperature variables of October and March of the following year during a wintering period showed a significant positive correlation with the population size of the Siberian crane after 3, 4, 5 and 6 years, which indicated that the influence of the wintering area climate on the Siberian crane population size has a time-lag effect. October and March were the early and late periods of winter when the Siberian crane finishes and starts its long-distance migration, respectively. We speculated that early and late winter may be key stages for the crane to replenish energy. The climate in these two months may be correlated with the quantity or quality of winter food, therefore, presumably a suitable temperature in these periods could improve individuals, especially encouraging young crane's survival, allowing more individuals to participate in breeding. Furthermore, the age of sexual maturity of the Siberian crane is usually 3-5 years, therefore, the increase in population numbers caused by the suitable temperature during wintering periods becomes obvious after 3-5 years. As for the climate in breeding areas, there was no significant correlation between Siberian crane population size and precipitation during the breeding period. However, the population size of Siberian crane in the Poyang Lake National Nature Reserve was significantly positively correlated with the air temperature variables in July in its breeding area during the same year. The air temperature in July in breeding areas may be correlated with the food availability for Siberian crane, which is especially important for bringing up young cranes. The stepwise linear regression result showed that the average minimum air temperature in October before the 6th year, the average maximum air temperature in October before the 2nd year, and the average air temperature in October before the 5th year were significant predictive factors for the population size fluctuation of the Siberian crane and accounted for 74.8% of the total population size change (<em>R</em>²=0.748, <em>F</em>=23.807, d<em>f</em>=27, <em>P</em>=0.000). The climate-related prediction model for the Siberian crane population size was <em>Y</em>=-18 101+53.150<em>X</em>₁+29.610<em>X</em>₂+22.363<em>X</em>₃, where <em>Y</em> was the annual maximum population size of the Siberian crane in the Poyang Lake National Nature Reserve, <em>X</em>₁ was the average minimum air temperature in October before the 6th year, <em>X</em>₂ was the average maximum air temperature in October before the 2nd year, and <em>X</em>₃ was the average air temperature in October before the 5th year. Only considering the climate factor, the model predicted that the population size of Siberian crane will show an obvious decrease in 2016.

PDF HTML阅读 XML下载 导出引用 引用提醒 鄱阳湖4种鹤类集群特征与成幼组成的时空变化 DOI: 10.5846/stxb201508191733 作者: 作者单位: 江西师范大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金资助项目（31260517） Temporal and spatial variations in the group characteristics and adult-juvenile composition of four crane species in Poyang Lake, China Author: Affiliation: Jiangxi Normal University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:2014年10月-2015年4月，采用样点法对鄱阳湖45个样点的白鹤（Grus leucogeranus）、白头鹤（G. monacha）、白枕鹤（G. vipio）和灰鹤（G. grus）的集群大小、集群类型和成幼组成进行调查。结果显示，白鹤的平均集群大小（23.86±10.26）只（集群数N=104），白头鹤（6.42±1.63）只（N=98），白枕鹤（6.09±2.55）只（N=105），灰鹤（5.55±1.26）只（N=246）。仅白头鹤中期集群大小显著小于后期，其余鹤类各时期及灰鹤各地区的集群大小差异不显著。鄱阳湖鹤类的集群大小并不符合警戒行为对集群大小的预测，生境质量差异可能是影响鄱阳湖鹤类集群大小的主要原因之一。4种鹤类均在1-5只个体的小集群中出现频度最高。白鹤在>35只个体集群中的个体比例最高，而白头鹤、白枕鹤和灰鹤在1-5只个体集群和>35只个体集群均有较高的个体比例。白鹤、白头鹤、白枕鹤和灰鹤均以家庭群为主，其家庭群所占比例分别为（64.29%，总集群数N=98）、（71.91%，N=89）、（70.77%，N=65）和（63.11%，N=206）。鄱阳湖鹤类以家庭群为主表明，保证充足的食物供应可能比花费更多的觅食时间更为重要。白鹤家庭群以2成1幼为主（65.08%），白头鹤（51.56%）、白枕鹤（52.17%）和灰鹤（47.69%）以2成为主。白鹤、白头鹤、白枕鹤和灰鹤群体的幼鸟比例分别为12.27%（个体数N=1695）、14.42%（N=416）、16.59%（N=229）和20.46%（N=655）。2成2幼集群比例极低表明，白鹤家庭同时抚养2个幼鸟成活的难度较其它3种鹤类大。4种鹤类在各时期的幼鸟比例差异不显著。在灰鹤个体数较多的3个地区中，都昌候鸟省级自然保护区（25.25%）和东鄱阳湖国家级湿地公园（25.14%）的幼鸟比例分别显著和极显著地高于鄱阳湖国家级自然保护区（14.24%）。鄱阳湖白鹤的幼鸟比例多年来均处于较低水平，白头鹤的幼鸟比例较2012-2013年冬季明显下降，灰鹤和白枕鹤种群可能处于稳定或增长状态。 Abstract:Poyang Lake is the largest freshwater lake in China, and many waterbirds, including four endangered crane species, overwinter at this lake each year. Feeding and resting are the behaviors primarily exhibited by the wintering waterbirds, that Poyang Lake provides good food and rest resources for them. However, no comprehensive data about the wintering ecology of these crane species exists. From October 2014 to April 2015, we investigated the group sizes and adult-juvenile compositions of the Siberian crane (Grus leucogeranus), hooded crane (G. monacha), white-naped crane (G. vipio), and common crane (G. grus) at 45 survey sites on Poyang Lake using the point count method. The results showed that the mean group sizes of the four crane species were (23.86±10.26) for the Siberian crane (group number N=104), (6.09±2.55) for the hooded crane (N=98), (6.09±2.55) for the white-naped crane (N=105), and (5.55±1.26) for the common crane (N=246). Crane group size in Poyang Lake did not conform to predictions based on their vigilance behavior. However, habitat quality may explain this discrepancy. The group size of hooded cranes at the mid-winter stage was significantly smaller than during the late winter stage, whereas other cranes showed no significant differences between the three wintering stages. The common crane group size also showed no significant differences between regions. The four species of cranes most frequently appeared in groups of 1-5 individuals. Most Siberian crane individuals appeared in groups of 35 individuals or more, whereas other cranes were in groups of 1-5, or more than 35 individuals. The Siberian crane (64.29%, total group number N=98), hooded crane (71.91%, N=89), white-naped crane (70.77%, N=65), and common crane (63.11%, N=206) appeared mainly in family groups, suggesting that ensuring an adequate supply of food was more important than increasing foraging time. The highest percentage of Siberian crane family group types was two adults with one offspring (65.08%), whilst two adults predominated in the hooded crane (51.56%), white-naped crane (52.17%), and common crane (47.69%) populations. The lower percentage of family types with two adults and two offspring indicated that Siberian crane families found it more difficult than the families of the other three cranes to raise two offspring at the same time. The percentage of juvenile Siberian cranes was 12.27% (individual number N=1695), 14.42% (N=416) for the hooded crane, 16.59% (N=229) for the white-naped crane, and 20.46% (N=655) for the common crane. There was no significant difference in the percentage of juveniles over the three wintering stages for any of the crane species. Duchang Provincial Migratory Birds Nature Reserve and East Poyang Lake National Wetland Park were found to contain significantly and extremely significantly (χ2=6.495, P=0.011 and χ2=9.012, P=0.003, respectively) more common cranes (25.25% and 25.14%, respectively) than Poyang Lake National Nature Reserve (14.24%). The percentage of juvenile Siberian cranes remained low in Poyang Lake, whereas that of the hooded cranes significantly decreased between 2014 and 2015 from the corresponding percentage of the population in 2012-13. The population of common cranes and white-naped cranes remained stable or increased, which suggested that Poyang Lake is able to maintain and develop healthy populations of these cranes. 参考文献 相似文献 引证文献

1998-2011年，采用地面同步调查法开展了鄱阳湖越冬灰鹤种群监测，并整合1984-2011年鄱阳湖国家级自然保护区历年的越冬灰鹤最大种群数量，分析了鄱阳湖灰鹤越冬种群动态以及影响其数量变化与空间分布的环境因素。结果表明，近13年来鄱阳湖区越冬灰鹤种群平均数量为（2 335±651）只，种群数量呈增长趋势，2011年冬季记录到最大种群数量7 640只。灰鹤越冬种群数量与10月平均最低气温以及10月平均气温存在显著正相关，与10月平均最大风速存在显著负相关，与各月的平均水位没有显著的相关性。每年冬季灰鹤在鄱阳湖呈聚集型分布。大湖池、大莲子湖、三湖、汉池湖、企湖、珠湖、南湖（共青）、大汊湖等8个湖泊是灰鹤的重点活动区，（74.9±5.6）%的越冬灰鹤分布在保护区之外。灰鹤的空间分布与滩地面积存在显著的正相关，与农田面积、人口密度、村庄数量、8月份初级生产力、11月份初级生产力等环境因子存在显著负相关。滩地面积是影响灰鹤空间分布的重要因子，对灰鹤利用频次空间变化的解释率为15.0%，与11月份初级生产力共同解释了灰鹤年平均群体数量空间变化的24.6%。如竞争、小生境结构、干扰等局地尺度的环境要素对灰鹤空间分布的影响研究将有助于更全面地认识鄱阳湖越冬灰鹤种群动态的影响机制。;Poyang Lake has been an important wintering site for Common Cranes. In this paper we monitored the dynamics of population size and spatial distribution of Common Cranes wintering in Poyang Lake during 1998-2011 and analyzed the potential determinants of its population dynamics. This was combined with the monitoring record of the annual maximum number of Common Cranes wintering in the Poyang Lake National Nature Reserve during 1984-2011. We illustrated the changing trend of this Common Crane population over a long time scale, and analyzed the impact of climate variation and water level change on the population size dynamics.<br>The results showed that the Common Crane population wintering in Poyang Lake significantly increased from 1998 to 2011, with an average population size of 2335±651 and a maximum of 7640 in the winter of 2011. The exponential curve fit well with the population growth trend (<em>R</em>²=0.808, <em>F</em>=46.234, d<em>f</em>=12, <em>P</em>=0.000). The wintering Common Cranes clustered in the Poyang lakes, with the lakes of Dahuchi, Dalianzihu, Sanhu, Hanchihu, Qihu, Zhuhu, Nanhu (gongqing), and Dachahu being the hotspots used by them. On average, (74.9±5.6)% of Common Cranes wintered outside nature reserves.<br>The spatial distribution of the common crane was significantly positively correlated with the areas of mudflat habitat, and was negatively correlated with areas of agricultural land, human density, village areas, and areas of net primary productivity (NPP) in August and November. The mudflat area was an important factor determining the spatial distribution of Common Cranes, which accounted for 15% of the spatial change in occurrence frequency, and when combined with the NPP factor in November, accounted for 24.6% of the spatial change in the average number of Common Cranes. The results mean that there are still factors which may affect the spatial distribution of Common Crane in Poyang lakes which were not assessed, such as competition, the structure of the microhabitat, and human interference, which maybe contribute to a more comprehensive understanding of the impact mechanisms of crane population dynamics wintering in the Poyang Lake.<br>In the Poyang Lake National Nature Reserve, the average annual maximum number of Common Cranes was 276±51 (<em>n</em>=28), which showed a significant linear increase (<em>R</em>²=0.176, <em>F</em>=5.537, d<em>f</em>=27, <em>P</em>=0.026), but there was a drastic annual fluctuation. The results of Pearson correlation analysis indicated that the annual maximum population number of Common Cranes wintering in the Poyang Lake National Nature Reserve was significantly positively correlated with the average air temperature in October (<em>r</em>=0.480, <em>P</em>=0.010, <em>n</em>=28) and the average minimum air temperature in October (<em>r</em>=0.480, <em>P</em>=0.010, <em>n</em>=28), and significantly negatively correlated with the average maximum wind speed in October (<em>r</em>=-0.450, <em>P</em>=0.016, <em>n</em>=28).<br>As for the water level of Poyang Lake, no significant correlation was found between the annual maximum population size of Common Cranes in the Poyang Lake National Nature Reserve and the annual minimum water level (<em>r</em>=-0.259, <em>P</em>=0.192, <em>n</em>=27), or the annual maximum water level (<em>r</em>=-0.373, <em>P</em>=0.051, <em>n</em>=28). There was also no significant correlation between the population size and the monthly average water level in the wintering period. Although the water level of Poyang Lake in winter was tested and found to significantly change the structural landscape of Poyang Lake wetland, influencing the availability of habitat and food, the water level of those lakes in the nature reserve was largely determined by the artificial aquaculture discharge time and velocity of the lake, which eliminated the influence of water level in Poyang Lake.

Study on habitat suitability and ecological network of rare cranes in Poyang Lake National Nature Reserve

Population survey showing hope for population recovery of the critically endangered Yangtze finless porpoise

“十三五”时期，长江流域水环境质量改善明显，但湖泊水质和富营养化状况改善滞后. 长江中游作为我国淡水湖泊集中分布区域之一，部分湖泊存在水环境质量恶化和富营养化加重问题. 本文以长江中游区域国家开展监测的洪湖、斧头湖、梁子湖、大通湖、洞庭湖和鄱阳湖这6个典型湖泊为研究对象，科学评价其2016—2020年水质和富营养化时空变化特征及关键驱动因素，探讨其成因及治理对策. 结果表明，“十三五”时期长江中游湖泊水质和富营养化程度存在较大差异，与2016年相比，2020年大通湖水质改善最为明显，梁子湖水质变差，总磷是影响长江中游湖泊水质类别的主要因子; 洪湖富营养程度恶化最为严重，斧头湖次之，TLI(SD)对长江中游湖泊富营养化评价贡献最大. 目前长江中游湖泊呈有机污染加重和叶绿素a浓度升高现象，洪湖、斧头湖和梁子湖主要与氮、磷营养盐浓度升高有关，而大通湖、洞庭湖和鄱阳湖受水文过程、流域纳污量和湖泊管理等非营养盐因素影响较大. 总氮和总磷仍然是影响“十三五”时期长江中游湖泊水质和富营养化的最主要驱动力，且各湖泊总氮和总磷浓度变化均具有较强正相关性，建议开展河湖氮、磷标准衔接工作，提出河湖氮、磷标准限值或考核目标，以完善河湖水环境质量标准和生态健康影响评价技术规范. 同时，建议长江中游湖泊在开展截污控源、内源控制和生态修复的同时，进一步深化流域管理，特别是对洞庭湖、鄱阳湖、梁子湖和斧头湖等跨行政区湖泊，以提高湖泊治理与修复的系统性和整体性.;During the 13th Five-Year Plan period, the water ecological environment quality of the Yangtze River Basin has improved significantly, but the improvement of lake water quality and eutrophication has lagged behind. As one of the concentrated distribution regions of freshwater lakes in China, the middle reaches of the Yangtze River have the problems of deterioration of water quality and aggravation of eutrophication. This article chosed six typical lakes monitored by national agencies, including Lake Honghu, Lake Futou, Lake Liangzi, Lake Datong, Lake Dongting and Lake Poyang, to scientifically evaluate their spatiotemporal changes, key drivers of water quality and eutrophication from 2016 to 2020, and to discuss the degradation causes and governance countermeasures. The results revealed significant spatiotemporal changes in water quality and eutrophication of those lakes. From 2016 to 2020, the water quality of Datong Lake improved mostly, while Lake Liangzi became worse. TP is the main factor affecting the lake water quality and TLI(SD) is most important in the lake eutrophication evaluation. The eutrophication in Lake Honghu is the most serious, followed by Lake Futou. The lakes in the middle reaches of the Yangtze River widely experienced increasing organic pollution and chlorophyll-a concentration. Such degradation in Lake Honghu, Lake Futou and Lake Liangzi is mainly related to the increase of nitrogen and phosphorus nutrients, while Lake Datong, Lake Dongting and Lake Poyang are greatly affected by non-nutrient factors such as hydrological processes, pollution holding capacity and Lake management. TN and TP are still the main drivers on the water quality and eutrophication of these lakes during the 13th Five-Year Plan period, and change synergistically in each lake. We propose to put forward the standard limits or assessment targets of nitrogen and phosphorus in rivers and lakes, to improve their environmental quality standards of rivers and lakes and the technical specifications for ecological health impact assessment. At the same time, it is recommended that the lakes in the middle reaches of the Yangtze River should carry out pollution control, endogenous control and ecological restoration. It is important to strengthen watershed management, especially the lakes across administrative regions such as Lake Dongting, Lake Poyang, Lake Liangzi, and Lake Futou to improve the system and integrity of lake governance and restoration.

Poyang Lake, Dongting Lake, and Taihu Lake are the largest freshwater lakes in the middle and lower reaches of the Yangtze River, China. In recent years, the eutrophication level of lakes has increased with the development of the social economy and caused many environmental and social problems. The concentrations of total nitrogen (TN) and total phosphorus (TP) are the key indicators of the degree of eutrophication, but the traditional ground monitoring methods are not capable of capturing such parameters in whole lakes with high spatial-temporal resolution. In this paper, empirical models are established and evaluated between the TN and TP and remote sensing spectral factors in the three lakes using Landsat 8 Operational Land Imager (OLI) satellite data and in-situ data. The results show that the inversion accuracy is higher than 75%. The TN and TP concentrations in the three lakes are inversed based on the Google Earth Engine (GEE) platform from 2014 to 2020 and their spatial-temporal variations are analyzed. The results show that the concentrations of TN and TP in Poyang Lake were decreased by 5.99% and 7.13% over 7 years, respectively, and the TN in Dongting Lake was decreased by 5.25% while the TP remained stable. The temporal changes in TN and TP concentrations displayed seasonal variations. A low concentration was observed in summer and high concentrations were in spring and winter. The average concentrations of TN and TP in Taihu Lake were higher than that of the other two lakes. The TP concentration was increased by 17.3% over 7 years, while the TN concentration remained almost stable. The variation in TN in Taihu Lake was the same as the growth cycle of algae, with higher value in spring and winter and lower value in summer, while the concentration of TP was lower in spring and winter and higher in summer. The spatial distribution of TN and TP concentrations in the three major lakes was significantly affected by human activities, and the concentrations of TN and TP were higher in areas near cities and agricultural activities.

Poyang and Dongting Lakes are two important river-connecting lakes with a complicated water system pattern in the middle reaches of the Yangtze River, China. Recently, extreme drought events occurred frequently in the two lakes. This study analyzed the characteristics and differences of hydrological droughts in Poyang and Dongting Lakes during the period of 1964–2016 and explored the correlation between drought and large-scale climate indices. The results showed that the hydrological droughts of Poyang and Dongting Lakes became increasingly serious. Especially after 2003, both lakes entered the dry season earlier and the intensity of drought was increased. The hydrological drought of Poyang Lake was more serious than that of Dongting Lake in spring (16.40%) and winter (14.26%), while the autumn drought in Dongting Lake (32.46%) was severer than that in Poyang Lake (27.65%). The spring droughts in the two lakes were significantly associated with droughts in their local catchments with the joint probabilities of 10.84 and 9.52%, while the autumn droughts were consistent with the hydrological droughts of the Yangtze River with large joint probabilities (26.39 and 27.76%). The changes in large-scale climate indices more significantly affected the drought in Poyang Lake than that in Dongting Lake, especially in autumn and winter.

Almost 95% of the world population of Siberian crane (Grus leucogeranus) winter in Poyang Lake, China. Here they forage on the tubers of the submerged aquatic macrophyte Vallisneria spiralis L. The growth and production of V. spiralis are regulated by the local hydrology, which might also be influenced by the changed hydrology of the Yangtze River induced by engineering projects. This thesis investigated the impact of dredging activities in the northern Poyang Lake and the Three Gorges Dam in the Yangtze River on the water turbidity and water level of Poyang Lake, analyzed how these hydrological changes influenced the underwater light climate of V. spiralis, and discussed their potential impacts on the growth and productivity of V. spiralis and further on the food habitat of Siberian crane in Poyang Lake. The principal results obtained can be summarized as follows: (1) Moderate resolution imaging spectroradiometer (MODIS) and Landsat thematic mapper (TM) images were compared for mapping the tempo-spatial dynamics of water clarity. Two multiple regression models including the blue and red bands of Landsat TM and MODIS respectively explained 83% and 88% of the variation of the natural logarithm of Secchi disk depth. On the basis of the comparison of water clarity predicted from Landsat TM and MODIS data as well as the advantages and contras of both sensors, it is concluded that MODIS offers the possibility to monitor the dynamics of water clarity more regularly and cheaply in relatively big and frequently cloud covered lakes like Poyang Lake. (2) The performance of the various Landsat TM bands for detecting dredging ships was explored in the turbid water of the northern Poyang Lake. The result revealed that the TM bands 1 to 4 had limitation especially in turbid water, while bands 5 and 7 better discriminated vessels from surrounding waters. Therefore, it is recommended using the mid-infrared bands of Landsat TM for operational ship monitoring in turbid water. (3) The possibility to strengthen inference of dredging impact while simultaneously monitoring vessels and water turbidity with remote sensing techniques was investigated in the northern Poyang Lake. Time-series MODIS images revealed a significant increase in water turbidity from 2001 onwards, while Landsat TM image analysis indicated a simultaneous increase in the number of vessels. Regression analysis further showed a highly significant positive relation (R2 = 0.92) between water turbidity and vessel number. On the basis of discussion of ship-related resuspension, final destinations of vessels and coincidence of vessel clusters with irregular dented patterns and turbid plume development, it is confirmed that dredging caused the increase in water turbidity. Therefore, it is concluded that simultaneously monitoring water turbidity and vessels enhanced the strength of evidence in remotely sensed dredging impact assessments. (4) Three extrapolation and interpolation methods were compared for predicting daily photosynthetically active radiation reaching the earth surface over the Poyang Lake national nature reserve. The result revealed that the triangulated irregular network (TIN) and inverse distance weighted (IDW)-based interpolation method produced more reliable result than the extrapolation methods. (5) The photosynthetically active radiation reaching the top of V. spiralis (PARlc) in Lake Dahuchi from 1998 to 2006 was modelled. The results revealed significant between year differences in PARtc, which were determined primarily by fluctuation in water level. Six years of Secchi disk depth records revealed seasonal switching of the lake from turbid at low water level in autumn, winter and spring to clear at high water level in summer. The highest PARtc occurred at intermediate water levels, which were reached when the Yangtze River forces Lake Dahuchi out of its turbid state in spring. The operation of the Three Gorges Dam, which will increase water level of Yangtze River from May to June may force Lake Dahuchi out of its turbid state earlier and increase the light intensity reaching the canopy and the production of V spiralis. It is concluded that the operation of the Three Gorges Dam might at the short term increase the light regime and productivity of V. spiralis and possibly affect the food habitat of Siberian crane in Poyang Lake. (6) A conceptual framework to integrate a simulation model of plant biomass for V. spiralis with remote sensing and a geographical information system was introduced. It is expected that the system, once implemented, could contribute to evaluate the impact of possible hydrological changes on the growth and productivity of V. spiralis, and assess whether tuber feeding bird populations are constrained by the regional availability of food resources in Lake Poyang. It is anticipated that these results provide a basis for the future research and necessary information for decision-making that need to be made by the responsible authorities to decide how to rationally manage this unique lake ecosystem.

The detrimental effect of oxygen depletion on fish is well known. Here a quantitative measure of anoxia is compared with the number of fish species in 52 south-central Ontario lakes. The anoxic factor (AF, days per year or per season) estimates the number of days that a sediment area equal to the lake surface area is overlain by anoxic water. It can be expressed separately as summer or winter AE Stepwise multiple-regression models were constructed with AF and common physical and chemical variables to predict fish species richness. Because some of the parametric regression assumptions were violated, the traditional statistics were evaluated with randomization tests to confirm significance. The best regression models included summer AF or lake surface area, or winter AF and mean depth, for subsets of acidic and circumneutral lakes; these models explained up to 75% of the variation in fish species richness. One of the models can be used to estimate the likelihood of winterkill. Anoxic factor was also correlated with the number of coldwater fish species present. The concept of AF can be used to model the distribution and number of fish species in stratified lakes and should be useful in the management of oxygen-dependent aquatic animals (e.g., finfish and shrimp) in freshwater and marine habitats.

Poyang Lake and Dongting Lake are the two largest freshwater lakes in China. They play a critical ecological role in regional sustainable development, which is closely related to water occurrence (WO). This study aimed to characterize the spatiotemporal changes, ecological impacts, and influencing factors of WO in the two lakes. First, this study utilized the Google Earth Engine (GEE) platform and all available Landsat images to retrieve the time series of WO in Poyang Lake and Dongting Lake on a two-year scale from 1989 to 2020. Then, the study explored the landscape variation intensity, landscape structure, and their ecological impacts on net primary production (NPP) and total nitrogen (TN) based on the landscape transfer rate (LTR), landscape indices, and geostatistical connectivity analysis. Finally, the study investigated the natural and human factors that influence the changes in WO. The major conclusions include the following: (1) the mean WO showed a significantly decreasing trend in the two lakes from 1989 to 2020. According to the LTR, the landscape variation in Dongting Lake was more intense before 2002, while after 2002, the landscape variation in Poyang Lake was more intense. (2) The landscape structure of WO gradually fragmented and diversified, along with decreasing hydrological connectivity in the two lakes. (3) The increase in NPP in Poyang Lake and the increase in TN in Dongting Lake were closely correlated with the changes in WO. (4) The upstream runoff showed a significantly positive correlation with the mean WO in Poyang Lake and the annual precipitation showed a significantly positive correlation with the mean WO in Dongting Lake; the influences of natural factors on WO changes became weaker. This study reinforces the understanding of long-term changes in the water body in Poyang Lake and Dongting Lake.

Poyang Lake provides wintering sites for several hundred thousands water birds every year. There are historical records of 310 species of birds in Poyang Lake National Nature Reserve (Abbr. in PYNNR), belonging to 17 orders, 63 families, and 158 genus, and including 125 water birds species belonging to 6 orders, 19 families, and 60 genus. The most amount of waterbirds in Poyang Lake are geese and swans, the second most are shorebirds. Dominant species of bird communities are whistling swan, swan goose and white-fronted goose. There are 19 species listed as threatened by IUCN. The Siberian crane is the most well-known wintering species in Poyang Lake. The number of Siberian cranes stablized in recent years. There are 18 species whose numbers are more than 1% of the total number of their global or migrant route's populations according to three separate of surveys. PYNNR is the most concentrated area for rare waterbird and precious species; at the same time, Nanhu and other adjacent areas to PYNNR such as the middle and south branch of the Gan River are also important habitats for rare waterbirds, and need more attention and conservation actions.

PDF HTML阅读 XML下载 导出引用 引用提醒 年龄、集群、生境及天气对鄱阳湖白鹤越冬期日间行为模式的影响 DOI: 10.5846/stxb201307291975 作者: 作者单位: 江西师范大学生命科学学院,江西师范大学生命科学学院,国际鹤类基金会,美国威斯康辛州,江西师范大学生命科学学院,江西师范大学生命科学学院,江西师范大学生命科学学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国际鹤类基金会资助（鄱阳湖水鸟以及栖息环境科学研究项目）；国家自然基金项目（31000196）；国家级自然保护区生态环境十年变化调查与评估（环保重大专项，STSN-7）；鄱阳湖科学考察之鸟类资源及其生境动态变化考察（20114ABG01100-1-03） The influence of age, flock size, habitat, and weather on the time budget and the daily rhythm of wintering Siberian Cranes in Poyang Lake Author: Affiliation: College of Life Science,Jiangxi Normal University,College of Life Science,Jiangxi Normal University,International Crane Fundation,Wisconsin ,USA,College of Life Science,Jiangxi Normal University,College of Life Science,Jiangxi Normal University,College of Life Science,Jiangxi Normal University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:于2012年1-3月和2012年12-2013年3月，采用瞬时扫描法研究了鄱阳湖国家级自然保护区越冬白鹤（Grusleucogeranus）的昼间时间分配模式和日活动节律，分析了年龄、集群大小、生境类型和天气对白鹤越冬行为的影响。结果表明，白鹤越冬期的主要行为有觅食、警戒、理羽、游走、休息和争斗。其中，觅食是鄱阳湖越冬白鹤主要行为，占其昼间活动时间的82.94%；警戒占11.94%，理羽占3.52%，游走占1.88%，休息占0.15%，争斗占0.02%。白鹤在越冬期间的觅食、游走、休息和争斗行为存在明显的昼间节律性，其中游走、觅食和争斗行为在每天的上午和下午各存在1个高峰，休息行为在中午出现一个高峰；警戒和理羽行为则没有显著的昼间节律变化。年龄、集群大小、天气和生境对白鹤的越冬行为具有显著的影响：幼鹤取食的时间显著多于成鹤，而警戒时间则显著的小于成鹤；与家庭群中的个体相比，集体群中的个体取食和争斗时间显著增加，警戒时间显著减少；在天气晴朗时，白鹤的警戒时间显著大于阴天的警戒时间，取食时间则显著少于阴天时白鹤的取食时间；白鹤在大风天气显著增加理羽行为；在有雾的天气会显著增加取食时间，减少警戒时间。在草洲和浅水两种生境中，白鹤的游走和理羽行为存在显著差异，而觅食和警戒行为没有显著的差异，这可能源于草洲和浅水生境相互毗邻，并且具有相同程度的人为干扰。GLM分析结果表明，年龄和集群大小、年龄和生境、集群大小和天气、集群大小和生境、天气和生境对白鹤昼间时间分配模式的影响存在显著交互效应。 Abstract:Siberian Cranes are the most highly specialized members of the crane family in terms of habitat requirements, morphology, vocalizations, and behavior. This critically endangered species is now found in only two populations: eastern and western. A central population of Siberian Cranes once nested in western Siberia and wintered in India, but there is a high probability that this population has been recently extirpated. It has beenestimated that about 4000 SiberianCranes haveoverwinteredin Poyang Lake in recent years. This lake has been an important wintering site for the cranes.From January to March, 2012, and from December 2012 to March 2013, we used instantaneous scanning sampling method to observe the wintering behavior of SiberianCraneswintering in the Poyang Lake National Nature Reserve, and we analyzed the effects of age, flock size, habitat, and weather on their wintering behavior. The results showed that the main behavioralhabits of the wintering cranes included feeding, vigilance, locomotion, grooming, resting, and hting. The cranes spent 81.1% of their daily time feeding, 13.1% being vigilant, 3.8% grooming, 1.7% in locomotion, 0.2% resting, and 0.1% fighting.The cranes showed a distinctive daily rhythm with feeding, locomotion, resting, and fighting, but no significant rhythm with vigilance and grooming behaviors. Feeding, locomotion, and fighting behaviors peakeddaily in the morning and afternoon, while resting behavior peaked in the middle of the day.The proportion of time engaged in different behaviorsinthe wintering cranes was significantly influenced by age, flock size, weather, and habitat:the juveniles spent significantly more time feeding and less time being vigilant than the adults; flocks of cranes spent significantly more time feeding, significantly less time being vigilant, and significantly more time fighting than the individuals in a family; on sunny days, the cranes spent significantly more time being vigilant and less time feeding than on cloudy days; on windy days the cranes spentsignificantly more time grooming; and on foggy days the cranes spent significantly more time feeding and less time being vigilant. In grassland and shoal habitats,there was no significant difference between the timespent feeding and being vigilant, which may be correlated with the fact that both of these habitats were neighboring and the craneswere confronted with the same degree of human disturbance in both habitats. However, in grassland and shoal habitats there were significant differences in the time spent grooming and in locomotion. The results of a general linear model analysis revealed that, in terms of time spent engaged in different behaviors, there was a significant relationship between age and flock size, age and habitat, flock size and weather, flock size and habitat, and weather and habitat inSiberianCranes. 参考文献 相似文献 引证文献

The sediment load in the Yangtze River downstream of the Three Gorges Dam (TGD) has substantially declined in recent decades. The decrease is more profound below the TGD, e.g., a 97% decrease at Yichang, compared with that at the delta apex, 1200 km downstream, e.g., a 75% decrease, implying along-river sediment recovery. Two large river-connected lakes, i.e., Dongting and Poyang Lakes, may play a role in the re-establishment of the river’s morphodynamic equilibrium, but a quantitative data-based understanding of this interaction is not yet available. In this work, we collected a series of field data to quantify the sediment gain and loss in the river-lake system in the middle-lower Yangtze River, and evaluate the lake’s response to the reduction in riverine sediment supply. We find that Dongting Lake and Poyang Lake shifted from net sedimentation to erosion in 2006 and 2000, and back to a sedimentation regime again after 2017 and 2018, respectively. Natural morphodynamic adaptation and sand mining play an important role in the regime changes in the Dongting Lake whereas sand mining dominates the abrupt changes in the Poyang Lake. The Dongting and Poyang Lake contributed maximum by 38% (2015) and 17% (2006) (respectively) to the sediment recovery in the erosion regime, whereas the riverbed erosion dominates the main sediment source. These changes in the relative contribution of sediment sources also indicates a response time of ~ 20 years in the lakes towards a new equilibrium state. It is noteworthy that the lakes’ buffer effects may be overestimated as the supplied sediment from the lakes is rather small compared to the significant dam trapping in the upstream basin and sediment source from downstream degradation. The results imply that river management and restoration should take into account of the river-lake interactions and feedback impact at decadal time scales.

SummaryFollowing an abnormal flood in 2010 at China’s Poyang Lake, we observed wintering Siberian CranesLeucogeranus leucogeranusswitch from foraging in the shallow-water wetlands they typically use to grassland habitats. These previously undocumented habitat selection patterns raised questions whether differences in crane behaviour such as foraging success existed between the two habitats and how those differences might affect this critically endangered species. Over two winters, we used the density of customary food items (tubers ofVallisneriaspp.) obtained from long-term monitoring efforts, Siberian Cranes flock behaviours, individual foraging success and estimated total flock foraging effort across both habitats. Novel foraging patterns by Siberian Cranes were associated with low densities ofVallisneriatubers across multiple sub-lakes within Poyang Lake National Nature Reserve (PLNR). Foraging success was higher in grasslands than in wetlands in winter 2010–2011, but higher in wetlands following a recovery ofVallisneriain 2011–2012. Subsequent to upland foraging during the winter of 2010–2011, we observed lower juvenile to adult ratio of Siberian Cranes at a fall migratory stopover location in north-eastern China despite indications of average environmental conditions in the nesting areas from 2010 to 2012. While grasslands adjacent to shallow-water habitats may be important refugia for wintering Siberian Cranes whenVallisneriais absent or inaccessible, and should be included in protected areas, multi-year dependence on grasslands for foraging could negatively impact population levels. Eliminating crab farming in protected areas and extending protection to shallow water areas sheltered from flooding by dykes could also help secure high quality foraging habitat under a variety of hydrological regimes. Novel foraging patterns by wintering Siberian Cranes represent a new challenge to the conservation efforts for this species that focus on shallow-water wetlands, and may be indicative of broader changes within Poyang’s ecosystem.