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1.
莫莫格自然保护区白鹤秋季迁徙停歇期觅食生境选择   总被引:1,自引:0,他引:1  
2008年秋季(10月8日—20日)及2009年秋季(9月20日—10月16日),通过样方法对觅食生境11个生态因子进行调查,利用卡方检验、资源选择指数和资源选择函数在莫莫格保护区对秋季迁徙停歇期白鹤觅食生境选择进行研究。结果表明,白鹤对距人为干扰源距离、植被密度、盖度、高度、植物性食物密度以及水深均具有选择性,但对宏观尺度干扰因子的选择性较低。其偏好觅食生境的特点为:距一级路>5000m,>二级路1500m以上,>三级路1000m以上,>居民点1000m以上,农田>1000m;植被密度20~50株/m2,盖度<10%,高度<20cm,扁杆藨草密度1~50株/m2,藨草密度1~10株/m2,水深40~60cm。白鹤秋季觅食生境资源选择函数为Logistic(P)=0.663+0.565×与一级道路距离+0.042×与二级道路距离+0.519×与三级道路距离+0.353×与居民点距离+0.169×与农田距离–0.455×植被密度–0.618×植被盖度–0.548×植被高度–0.158×扁杆藨草密度–0.404×藨草密度+0.920×水深,T(x)=eLogistic(p)/[1+eLogistic(p)],模型正确预测率为82.9%。  相似文献   

2.
许宇田  童春富 《生态学报》2018,38(19):7034-7044
海三棱藨草(Scirpus mariqueter)为长江河口盐沼湿地先锋植物。以长江口九段沙湿地为主要研究区域,在江亚南沙、上沙、中下沙等不同区域设置固定站点,进行植被和环境因子的取样调研,分析研究了海三棱藨草的生物量分配特征及其主要影响因子,以期为海三棱藨草的培育与恢复、盐沼湿地生态系统的保护与利用提供科学依据。结果表明:(1)不同站点海三棱藨草的茎基高度、球茎生物量占比、根茎与球茎之比均不存在显著差异(P0.05),而植株密度、植株高度、根茎生物量占比、果实生物量占比、茎叶生物量占比、须根生物量占比、果实与根茎之比、果实与球茎之比在不同站点间存在显著差异(P0.05);(2)不同站点的沉积物电导率、盐度、容积密度(5—10、25—30 cm土层)、总碳含量(10—15、20—25、25—30 cm土层)、总氮含量(5—10 cm土层)存在显著差异(P0.05);(3)海三棱藨草的果实与根茎的生物量之比和沉积物5—10、25—30 cm总碳含量,0—5、5—10 cm总氮含量,0—5 cm容积密度,茎基高度6种因子的组合存在极显著相关(P0.01);而其他生物量分配指标与本文涉及到的环境因子、植物表形参数均不存在显著相关性(P0.05)。海三棱藨草生物量分配特征是其自身生长特征与环境因子综合作用的结果。在今后的研究中需拓展生境因子涵盖范围,深入分析多因子综合作用对海三棱藨草生物量分配特征的影响。  相似文献   

3.
迁徙停歇期鸻鹬类在崇明东滩潮间带的食物分布   总被引:1,自引:0,他引:1  
朱晶  敬凯  干晓静  马志军 《生态学报》2007,27(6):2149-2159
崇明东滩是鸻鹬类在东亚-澳大利西亚迁徙路线上重要的迁徙停歇地,滩涂上的底栖动物为迁徙的候鸟提供了丰富的食物来源。采用圆筒取样法对崇明东滩潮间带的大型底栖动物群落进行了研究。研究表明,该区域的大型底栖动物主要有腹足类、双壳类、甲壳类、多毛类环节动物及昆虫幼虫等类群。其中以腹足类密度最高((2805±360)个/m^2),约占底栖动物总密度的80%。其次为双壳类,密度为(320±31)个/m^2。双壳类的生物量(湿重)为(51.4±7.8)g/m^2,腹足类(38.7±5.1)g/m^2,两者占底栖动物总生物量的90%以上。不同类群的底栖动物在潮间带的空间分布上有显著差异。腹足类主要分布在海三棱藨草带,双壳类在海三棱藨草外带至光滩区域分布较多。从空间分布来看,腹足类在崇明东滩的北部区域分布较多,在南部区域则明显减少。双壳类在南北各条样线上的平均密度没有显著差异。除双壳类在秋季迁徙期的密度高于春季迁徙期外(P〈0.001),其他类群的底栖动物在春季和秋季迁徙期的密度均无显著差异(P〉0.05)。  相似文献   

4.
湿地恢复过程中,时常有外来种或本地杂草入侵。土壤种子库作为未来植被的潜在种源,对湿地恢复效果具有重要的指示意义。在莫莫格国家级自然保护区,以恢复白鹤栖息地(扁秆藨草(Scirpus planiculmis)沼泽)为目的,进行了退化湿地的水文恢复;但退化湿地恢复2a后,一年生杂草长芒稗(Echinochloa caudata)在大部分区域成为建群种。以长芒稗入侵湿地和扁秆藨草自然湿地为研究对象,对比分析了长芒稗和扁秆藨草的土壤种子库及生长结实特征。结果表明,在自然湿地扁秆藨草种子库规模是长芒稗的18.42倍,而在恢复湿地长芒稗种子库大小是扁秆藨草的5.04倍。与自然湿地相比,扁秆藨草种子库密度在入侵湿地明显减少,但仍保留了一定量具有活力的种子(664.32±105.98)粒/m~2,这与研究区扁秆藨草较高的种子生产力(9210.4±1513.4)粒/m~2及种子较强的浮力(FP50=39.7d)有关,说明扁秆藨草具备通过种子库或水传播恢复的潜力。长芒稗土壤种子库密度在入侵湿地高达(3345.9±520.3)粒/m~2,明显高于自然湿地种子库规模(P0.01),说明恢复湿地受长芒稗入侵影响严重,这与长芒稗较高的种子生产力(7621.4±376.25)粒/m~2及较弱的种子浮力(FP0=5d)有关,同时也表明长芒稗通过水传播扩散的能力较弱。另外,研究区长芒稗平均高度超过1m,且盖度较大,不仅阻碍扁秆藨草种子的水播,也降低了到达地表的光照水平,从而抑制扁秆藨草更新。因此,在莫莫格受长芒稗入侵湿地,于开花结实前收获长芒稗地上植物体及凋落物应是限制长芒稗扩展、同时促进扁秆藨草恢复的有效措施。  相似文献   

5.
互花米草与海三棱藨草的生长特征和相对竞争能力   总被引:9,自引:0,他引:9  
外来物种互花米草(Spartinaalterniflora)已对我国特有种海三棱藨草 (Scirpusmariqueter)发生了竞争取代。作者通过在长江口崇明东滩湿地取样和盆栽竞争实验,比较了二者的主要生长特征和种间相对竞争能力。结果表明:无论是先锋种群还是成熟种群,互花米草的高度、盖度、地上生物量、地下生物量和平均每花序种子数都显著大于海三棱藨草;海三棱藨草的密度和单位面积结实枝条数显著大于互花米草。两种植物成熟种群的单位面积种子产量和种子的萌发率没有显著差异。种内竞争和种间竞争显著降低了两种植物的平均每株产生的无性小株数、结实株数、地上生物量和地下球茎数(海三棱藨草产生球茎),互花米草的种间竞争能力 (相对邻里效应指数 )显著大于海三棱藨草。互花米草在生长上的优势可能导致其在种间竞争上的优势,从而使互花米草能够在海三棱藨草群落中成功入侵。  相似文献   

6.
受伤和体弱白鹤的救护及放归是白鹤保护的重要方式之一。2014—2016年间,先后对8只救护白鹤和2只野生白鹤进行环志并安装卫星跟踪器,根据所获得的卫星跟踪数据来分析比较救护白鹤与野生白鹤在秋季迁徙路线和在重要中途停歇地的最大日活动距离、活动区分布和面积、生境类型等方面的异同。结果显示,救护白鹤放归当年与放归次年以及救护白鹤放归当年与野生白鹤的秋季迁徙路线和活动规律之间存在明显差异,但救护白鹤放归次年与野生白鹤之间差异不明显。(1)放归当年,4只救护白鹤在农田和水塘停歇1个月左右,停歇时长明显高于野生白鹤和放归次年的救护白鹤。(2)救护白鹤放归当年在跨海方式、登陆地点、停歇地点以及登陆后的迁徙方向上表现出多样性和不确定性,其中部分个体在迁徙过程中有停顿徘徊、迷失迁徙方向的现象,且跨越渤海和大别山的距离大于放归次年的救护白鹤和野生白鹤。(3)救护白鹤放归后4天内每日最大活动距离小,而后高低分化明显,无明显规律,而救护白鹤放归次年的每日最大活动距离规律变化与野生白鹤较一致。(4)与救护白鹤放归次年以及野生白鹤的活动规律相比,救护白鹤放归当年的栖息地位点变化频繁,具体表现为生境类型选择的多样化,且无明显规律,同时活动区面积较小。探索救护白鹤放归野外后与野生白鹤迁徙路线和活动规律的差异,对救护白鹤的科学放归具有指导意义。  相似文献   

7.
以莫莫格国家级自然保护区常见植物三江藨草(Scirpus nipponicus)为研究对象,设置低(5 cm)、中(35 cm)、高(65 cm) 3个水位和低(4 mmol·L-1)、中(8 mmol·L-1)、高(12mmol·L-1) 3个氮浓度交互的室内控制实验,探究不同水位和氮浓度对湿地植物三江藨草幼苗生长及生物量分配的影响。结果表明:水位对三江藨草幼苗生长、生物量及其分配均产生显著影响(P<0.05),随着水位的升高,三江藨草株高增加,分株数、球茎数及根生物量降低,根茎、球茎、地下、地上和总生物量均呈先增加后降低的趋势;植株地上生物量分配增加,地下(包括根和球茎)生物量分配降低;氮浓度仅对植株株高、球茎数以及地下与地上部分的生物量分配有显著影响(P<0.05),对分株数及生物量的累积均无显著影响(P>0.05);综合三江藨草幼苗的生长特征和生物量累积,认为其生长的最适宜水位为35 cm;且低水位有利于植株对氮的吸收,高水位和高氮浓度限制植株的生长。  相似文献   

8.
崇明东滩南部滩面高程、土壤盐度在空间上呈明显的梯度变化规律。高程整体西高东低、北高南低,盐度东北高、西南低,两者共同限制着盐沼植物在空间上的分布。该文围绕崇明东滩南部主要植被类群及其空间分布,探讨了土壤盐度、潮滩高程两大环境因子与植物种群分布的对应关系。基于2013年夏、秋季植被空间网格采样和空间插值,分析了东滩南部植物的空间分布现状,发现不同植物类群在高程和土壤盐度上存在极显著的差异(p0.01)。高程差异:莎草科类群主要分布于高程区间2.93–4.07 m的低潮滩,禾本科主要集中分布在高程3.13–4.31 m的中、高潮滩;盐度差异:海三棱藨草(Scirpus mariqueter)和互花米草(Spartina alterniflora)优势种群植被覆盖区表层30 cm的平均土壤盐度为(3.2±0.6)g·kg–1,显著高于其他类群植物分布区的平均土壤盐度(2.0±0.3)g·kg–1(p0.01)。崇明东滩湿地生态系统的关键种兼先锋种——海三棱藨草,分布高程介于2.53–3.97 m,而互花米草能适应海三棱藨草80%的高程区间,两者在高程上存在竞争关系。统计数据显示,研究区域中近90%的海三棱藨草分布在研究区东北部,土壤盐度范围为1.6–4.5 g·kg–1,海三棱藨草、互花米草能较好地适应该空间内的盐度胁迫,两种植物在此交替出现。但是在高程和土壤盐度的综合作用下,互花米草的生长状况更好,因此该区的海三棱藨草很可能会被互花米草逐步取代。对各类群植被分布和优势面积的研究发现,海三棱藨草总分布面积为294 hm2,优势群落面积120 hm2,海三棱藨草仅占莎草科植物总优势面积的15.7%,占研究区总面积的6.9%,在6种主要植物(芦苇(Phragmites australis)、白茅(Imperata cylindrica)、互花米草、糙叶薹草(Carex scabrifolia)、藨草(Scirpus triqueter)、海三棱藨草)中比重最小,这给保护区内海三棱藨草种群的恢复和保护带来极大的挑战。  相似文献   

9.
白鹤(Grus leucogeranus)为IUCN红色名录极危物种, 在中转停歇地松嫩平原的停歇生境为湿地, 近年来却出现多数个体迁离湿地转移到玉米(Zea mays)地取食停歇的现象。为探究迁徙白鹤在中转停歇地取食生境利用变化的原因, 我们于2020年9月至2021年11月对该区域白鹤种群数量和取食生境等进行观测, 并对食物资源量进行了分析。结果表明: (1)在农田生境取食的白鹤个体数量占比达72.7%, 是湿地生境的2.66倍。农田已成为迁徙白鹤在中转停歇地的主要取食生境之一。(2)根据不同的收割方式, 农田可提供的总能量是湿地的1.24-2.79倍; 白鹤在农田的日摄入能量约为湿地的1.56倍。(3)在农田白鹤的每日取食时间约占总活动时长的53.5%, 是湿地的1.67倍, 取食成功率是湿地的1.56倍。白鹤取食生境利用变化的主要原因可能是由于水位变化、食物资源变化、取食难易度不同和人为干扰等综合作用导致。为有效保护和管理白鹤生境, 建议合理进行湿地生态补水调控并恢复白鹤主要食源植物, 开展农业用地保护计划并设置自然保护小区。  相似文献   

10.
子午岭辽东栎群落乔木种间联结与取样面积   总被引:7,自引:1,他引:6  
以x2检验、种间联结系数(AC)、Person相关系数(r)、方差比率(馏)和某一取样面积尺度下的样方中未共同出现的物种对数目Na为参数,探讨黄土高原子午岭辽东栎群落主要乔木种间联结特性与取样面积的关系.x2检验和AC分析表明,显著的种问联结关系仅出现在25和50 m22个取样面积中;相关分析表明,显著的种间相关出现在取样面积25~200 m2,但r值的变化在25~100 m2较稳定;VR分析未能有效地区分不同取样面积中多物种关联的特性;Na值在面积为100~200 m2、样方数为40~80时较稳定.从合理的样方面积和适当的样方数量综合考虑,样方面积在100 m2、样方数为45个,能比较客观、稳定地反映辽东栎群落植物种间联结特性.  相似文献   

11.
鄱阳湖是世界重要的候鸟越冬地,承载了全球约98%的白鹤(Leucogeranus leucogeranus)。然而,近年来鄱阳湖沉水植被退化严重,白鹤的传统食物苦草(Vallisneria spp.)冬芽丰富度急剧减少。食物短缺导致白鹤的觅食生境由自然湿地的浅水生境转移至稻田、藕塘等人工生境,稻田在白鹤保护中发挥的作用日益突出。了解鄱阳湖周边稻田对白鹤的承载力可为白鹤的保护和管理提供科学依据。为此,调查了鄱阳湖周边稻田散落稻谷的生物量,测量了稻谷的营养成分,并利用遥感影像对鄱阳湖周边10 km范围内稻田的总面积进行估算,从而得出鄱阳湖周边稻田散落稻谷能提供的总能量。然后,计算稻田中以稻谷为主要食物的6种鸟类的日能量消耗,用以表示日能量摄入。最后,依据稻田能提供的总能量、鸟类的日能量摄入、鸟类的越冬时长、以及各种鸟类的数量占比,计算得出鄱阳湖周边稻田能承载的白鹤数量。结果表明,鄱阳湖周边稻田散落稻谷的生物量为6.494 g/m2,环鄱阳湖周边10 km范围内稻田的总面积为1984.46 km2,这些稻田能承载的鸟类总数量为140860只,其中能承载的白鹤数量为10775只,超过了全球白鹤的总数量(3500-4000只)。因此,鄱阳湖周边稻田能为白鹤等鸟类提供丰富的食物资源。  相似文献   

12.
The study of habitat selection and diet has a long history in ecology. This is often used to assess the functional roles of wetland in biodiversity conservation. Shifting habitat and diet may be one of the survival strategies during extremely adverse conditions. Therefore, sudden changes in habitat selection may indicate the deterioration of the habitat quality, and management interventions are necessary. Siberian crane (Grus leucogeranus) became critically endangered due to loss of habitat, and is currently a global conservation focus. Every winter, more than 95% of the species'' global population congregates at Poyang Lake, and feeds on tubers of Vallisneria spiralis in shallow water and mudflat habitat. In this study, we reported the first sighting of large numbers of Siberian cranes foraging at wet meadows, where they fed on a different plant, Potentilla limprichtii due to extreme scarcity of their preferred tuber. To understand how well the cranes adapted to such unusual habitat, field surveys to assess the distribution of cranes across different habitats, and food availability in each habitat were carried out in the winter of 2011. Field observations on crane behaviors at different habitats were also conducted. Results show that cranes displayed significantly different behavior patterns when using the wet meadow, compared to the crane''s optimal habitat - shallow water and mudflat. Both juveniles and adults spent significantly less time foraging, and more time alerting in meadows than in shallow waters and mudflats. These results indicated that the meadow might be a suboptimal wintering ground for Siberian crane, which helped the cranes survive from extreme unfavorable conditions. To some degree, this finding alleviates the general concern over the fluctuating of its food resources which was caused by hydrological disturbances. However, more studies are needed to assess the consequences of such diet and habitat shift for crane survival.  相似文献   

13.
There is an increased need for high-yield protein production platforms to meet growing demand. Tuber-based production in Solanum tuberosum offers several advantages, including high biomass yield, although protein concentration is typically low. In this work, we investigated the question whether minor interruption of starch biosynthesis can have a positive effect on tuber protein content and/or tuber biomass, as previous work suggested that partial obstruction of starch synthesis had variable effects on tuber yield. To this end, we used a RNAi approach to knock down ATP/ADP transporter and obtained a large number of transgenic lines for screening of lines with improved tuber protein content and/or tuber biomass. The initial screening was based on tuber biomass because of its relative simplicity. We identified a line, riAATP1-10, with minor (less than 15%) reduction in starch, that had a nearly 30% increase in biomass compared to wild-type, producing both more and larger tubers with altered morphological features compared to wild-type. riAATP1-10 tubers have a higher concentration of soluble protein compared to wild-type tubers, with nearly 50% more soluble protein. We assessed the suitability of this line as a new bioreactor by expressing a human scFv, reaching over 0.5% of total soluble protein, a 2-fold increase over the highest accumulating line in a wild-type background. Together with increased biomass and increased levels in total protein content, foreign protein expression in riAATP1-10 line would translate into a nearly 4-fold increase in recombinant protein yield per plant. Our results indicate that riAATP1-10 line provides an improved expression system for production of foreign proteins.  相似文献   

14.
鄱阳湖苔草湿地甲烷释放特征   总被引:2,自引:0,他引:2       下载免费PDF全文
胡启武  朱丽丽  幸瑞新  尧波  胡斌华 《生态学报》2011,31(17):4851-4857
2009年5月-2010年4月在鄱阳湖南矶湿地国家级自然保护区选择以灰化苔草为建群种的洲滩,设置土壤-植物系统(TC)、剪除植物地上部分 (TJ)2个试验处理,利用密闭箱-气相色谱法测定了鄱阳湖典型苔草湿地的甲烷(CH4)释放通量。结果表明:1)TC、TJ 2个试验处理CH4释放速率变化范围分别为-0.094-17.75 mg · m-2 · h-1、-0.122-19.16 mg · m-2 · h-1,均表现出明显的季节变化规律;2)地表未淹水期间,剪草处理CH4释放显著高于非剪草处理(t=2.69, P<0.05);地表淹水达到15 cm后,剪草处理CH4释放明显低于非剪草处理。3)土壤5 cm温度、土壤水分与2处理非淹水期间CH4释放速率均呈显著正相关,是非淹水期间CH4通量变化的主要控制因子,2因子能够共同解释非淹水期苔草湿地65%-74%的CH4通量变异;4)试验期间,苔草湿地CH4释放量约为12.77 gC/m2,相当于同期土壤有机质分解碳排放量的4%,甲烷释放的碳消耗不足苔草湿地年NPP的1%。  相似文献   

15.
Meloidogyne incognita-infected and noninfected tubers of yellow nutsedge (Cyperus esculentus) and purple nutsedge (Cyperus rotundus) were treated with 56 L/ha 1,3-dichloropropene (1,3-D) in microplots and subsequently examined for tuber and nematode viability in the greenhouse using a chile pepper (Capsicum annuum) bioassay system. The study was conducted three times. Nutsedge tuber viability and M. incognita harbored in both yellow and purple nutsedge tubers were unaffected by 1,3-D treatment. Nematode reproduction on nutsedges and associated chile pepper plants varied among years, possibly due to differing levels of tuber infection or soil temperature, but was not affected by fumigation. The presence of M. incognita resulted in greater yellow nutsedge tuber germination and reproduction. The efficacy of 1,3-D for management of M. incognita in chile pepper production is likely to be reduced when nutsedges are present in high numbers, reinforcing the importance of managing these weeds and nematodes simultaneously.  相似文献   

16.
The objective of this study was to examine the impact of crowding (stocking density) on food consumption and growth of juvenile Sepia officinalis reared at 17 and 25 °C. Two groups of 75 cuttlefish each were reared in closed seawater systems with water temperatures of 17 and 25 °C. Each group was subdivided into two treatments (three replicates per treatment): low-density (equivalent to 100 Sepia m−2) and high-density (equivalent to 400 Sepia m−2). Food consumption was measured daily and live wet body weight (g) was measured weekly over a 5-week study. The 25 °C treatment resulted in significantly higher growth rates and food consumption compared to the 17 °C treatment. Stocking density had no statistically significant effect on food consumption, gross growth efficiency (GGE), or weight at either temperature. However, the high-density treatments had slightly lower GGE values overall and growth in weight at 25 °C was slightly but consistently lower in the high-density treatment suggesting that stocking densities of 400 Sepia m−2 may be approaching levels that impact feeding and growth.  相似文献   

17.
The control of field tuber dormancy in the yam (Dioscorea cayenensisD. rotundata complex) is poorly understood. Although studies have examined single environmental factors and chemical treatments that might prolong tuber dormancy and storage, only a few were focused on further tuber sprouting. The present study concerns microtubers obtained by in vitro culture. When microtubers were harvested (after 9 months of culture) and directly transferred on a new medium without hormones, the tubers rapidly sprouted in in vitro conditions. No dormancy was observed in this case. Harvested microtubers were also stored dry in jars in sterile conditions during 2 to 18 weeks before in vitro sprouting. In this case, microtubers stored during 18 weeks sprouted more rapidly than those stored 8 weeks. A constant “dormancy-like period” (storage duration + sprouting delay) was observed, between 20 and 28 weeks respectively for the more rapid and the slower microtubers. The size of the tubers used for the storage had great influence on further sprouting. The larger they were, the better they sprouted. Light during storage had no effect on the sprouting delay while a temperature of 25 °C permit a quicker sprouting than 18 °C. The medium used to obtain microtubers could also have an effect on sprouting rate.  相似文献   

18.
Oxamyl was applied to both uncut and cut potato tubers in aqueous solutions of 1,000 to 32,000 μg/ml. Emergence in greenhouse pots was delayed for a day or more after soaking cut tuber pieces in 32,000 μg/ml. After 10 weeks plant growth was greater, relative to the control, when Pratylenchus penetrans-infested soil was planted with cut tubers soaked for 20 minutes in 32,000 μg/ml. Soaking for 40 minutes did not increase nematode control nor affect plant growth. Oxamyl applied to tubers at 1,000 μg/ml reduced the numbers of P. penetrans in the soil by 20% and in the roots by 35%; at 32,000 μg/ml, the numbers of P. penetrans in the soil were reduced by 73-86% and in the roots by 86-97%. The numbers of P. penetrans did not increase in the roots of plants developed from cut tubers soaked in 32,000 μg/ml over a period of 10 weeks, but numbers of lesion nematodes had begun to increase in the soil.  相似文献   

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