26 resultados para Spatial Ecology
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
本文从物种和景观两个组织水平上研究了气候、土壤、地形等自然环境因子和人类活动因子对生物空间分布格局的影响。基于锡林河流域地理信息系统各环境因子的专题数据,利用空间异质性分析方法研究了锡林河流域环境因子的空间分布格局;基于锡林河流域野外调查数据,运用空间异质性分析方法研究了重要物种的空间分布格局,并采用典范对应分析(Canomc Correspondence Analvsis,CCA)方法分析了物种分布与环境因子的关系:基于锡林河流域地理信息系统各环境因子的专题数据,研究了锡林河流域植被斑块的空间格局特征及其与环境因子的关系,并采用典范对应分析方法分析了植被类型组成与环境因子的关系:基于内蒙古草原生态系统定位研究站放牧样地的样方调查数据.采用空间异质性分析方法,研究了放牧压力对物种空间分布格局的影响:基于多年的卫星遥感数据,采用建模和对比等方法,研究了定居放牧方式下植被状况空间变化规律及植被状况时空变化与人类活动、社会经济发展的关系。通过上述分析,得到的主要结论如下: 1、锡林河流域各个环境因子都具有自己的空间特征尺度,共同形成多尺度等级体系,按特征尺度的大小可以分为如下3个组: ·小尺度组(15km左右):有机暖、全N的较小的特征尺度 ·中尺度组(30~50km):T1,碳酸钙含量.PER、全N和海拔高度的较小的特征尺度 ·大尺度组(100km左右):ANNR,PER、全N和海拔高度的较大的特征尺度多尺度等级的生态学意义是它反映生态变量异质斑块的镶嵌和包含特征,环境因子多尺度等级体系反映共性,具有普遍性:反映生态关系,具有生态学意义。 2、对物种空间异质性的Mantel检验和半方差分析得到了一致的结果产即羊草、糙隐子草和星毛萎菱菜在锡林河流域的空间分布呈现随机特征,而大针茅和冷蒿则表现为十分显著的格局特征。按分布格局的显著程度从大到小排列为冷蒿>大针茅>星毛萎菱菜>糙隐子草>羊草。理论半方差图显示大针茅和冷蒿的空间自相关域分别为30.447公里和30公里。物种空间分布格局是受自然条件、人类活动以及它们自身的生理生态特征综合决定的,物种自身的生理生态特征决定了它们对外界环境变化的适应性反应机制,而自然与人类活动这两种因素在空间的交错配置决定了物种适应性反应的方向和程度,从而综合导致物种空间分布格局的形成。 3、对锡林河流域物种分布与环境因子关系的CCA分析和交叉半方差方法分析显示:1)气候因子(11个指标)、土壤性状因子(3个指标)和地形因子(3个指标)对物种分布的贡献率分别为11.2%、9.5%和11%,三者总和为31.7%。2)各个环境因子对物种分布空间作用方向具有一致性,物种分布与环境因子几乎都在135。和157.5。两个方向上具有相对明显的相关性,从锡林河流域来看,这两个方向反映了气候、土壤以及地形从东南往西北的变化梯度方向。 4、对锡林河流域14个植被景观指数进行的PCA分析表明,锡林河流域植被斑块空间分布的物理特征主要表现在斑块的数目和大小方面,其次是在斑块的多样性方面,并可将它们分为4个组,分别反映锡林河流域植被斑块的不同特征: ·第一组:NP、PRD、LPI、MPS、PSSD和TE,主要反映景观斑块在数量和大小方面的特征; ·第二组:SHDI、SIDI、SHEI和SIEI,主要反映景观斑块的多样性特征; ·第三组:PSCV和[J].主要反映景观斑块之间的相互邻接程度; ·第四组:MSI和AWMSI,主要反映景观斑块的形状特征。 MPS和PSSD两个指数与环境因子无论是在相关系数的性质还是显著程度上都保持了很好的一致性,它们与纬度(LAT)及可能蒸散率(PER)呈极显著的正相关关系,而与经度(LNG)、海拔高度(ALT)、年平均降水量(ANNR)及土壤有机质含量(0RG)呈极显著的负相关关系:平均形状指数(MSI)只与LAT呈显著的正相关关系;多样性指数和扩散毗连指数与任何一个环境因子都没有表现出显著的相关性。 5、锡林河流域植被分布与环境因子的关系CCA排序方法分析表明,气候因子(11个指标)、土壤性状因子(3个指标)和地形因子(3个指标)对植被分布的贡献率分别为19.8%、11.1%和14.5%,三者总和为45.4%。环境因子在植被和物种两个水平上的贡献率表现了相似的特点,自然环境因子不能完全解释植被的空间分布,人类活动的影响应该受到重视。 6、放牧压力对物种空间分布格局的研究表明: ·牧压对温带典型草原物种的空间分布格局有明显的影响。随着牧云的增大,属于原生群落物种的羊草与大针茅空间分布的随机性减小,空间自相关尺度逐渐增大;而对于退化过程中的入侵物种冷蒿和星毛萎菱菜,其空间分布的随机性逐渐增大.空间自相关尺度也呈增大趋势。在牧压胁迫超过一定水平时,冷蒿空间分布的自相关尺度开始下降,而星毛萎菱菜的空间分布格局则表现出强烈的随机性。 ·物种空间格局的变化是反映群落演替过程较为稳定的特征,适用于不同放牧条件下 群落之间的比较。 7、利用遥感数据对人类活动对植被影响的研究表明: ·定居放牧方式下,NDVI随定居点距离的变化格局经历了3个阶段。第一阶段,草场处于原生阶段,NDVI不随距离变化;第二阶段,定居点附近开始局部退化,NDVI随距离增加而增大:第三阶段,退化区域扩大,NDVI不随距离变化。 ·在草场局部退化阶段,NDVI随距离的变化呈对数函数规律,定居点的放牧区具有放牧半径、原生NDVI值、NDVI变化率等特征。根据这些特征、NDVI对数规律以及NDVI与地上生物量的关系可以推测定居点的总载畜量。 ·锡林河流域从87年到85年NDVI值降低最大的区域为流域的中部和南部,这与这一区域人类活动强度以及社会经济发展具有密切关系。
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P> Widespread hunting throughout Amazonia threatens the persistence of large primates and other vertebrates. Most studies have used models of limited validity and restricted spatial and temporal scales to assess the sustainability. We use human-demographi
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黑颈鹤中部越冬种群是三个越冬种群中最为濒危的一个。由于栖息地退化和 丧失等因素的影响,其分布区逐渐萎缩,在大多数分布区(大理、鹤庆、丽江、 祥云),黑颈鹤已经消失或偶见。目前稳定的越冬区仅见于香格里拉县境内的纳 帕海和碧塔海,其中90%以上的个体在纳帕海越冬。纳帕海已经成为中部种群最 重要的越冬地。 本论文主要报道了2007 年~2010 年有关种群数量、空间利用模式、栖息地 偏好以及迁徙生态等工作成果。 1) 纳帕海黑颈鹤种群呈增长态势,数量由2004 年的281 只增长到2007 年的325 只。但2007 年的幼体新增率仅为8.1%,大大低于2004 年的16.3%。 这也说明黑颈鹤繁殖的成功率在不同的年份波动比较大。 2) 黑颈鹤在纳帕海的总利用区域(100%等值线)面积为990.9ha,而核心 利用面积(50%等值线)仅为42.3ha,分别占总研究区域的28.2%和1.2%。每个 月的平均90%利用区域面积为217.5 ±40.8ha (值域= 108.0~317.4ha, N = 5 个 月) ,月平均核心利用区域为25.5 ±5.1ha (值域=10.4~38.6ha, N = 5 个月)。 涝季和旱季相比,黑颈鹤的总利用区域和核心利用区的面积没有显著差异(t-检 验,P 均>0.05)。在不同的月份黑颈鹤会利用不同的区域,任意两月的总活动面 积重叠率为39.1 ±3.8% (值域= 21.3~57.2%),而核心活动面积重叠率仅为9.9 ±3.0%(值域= 0~28.5%)。栖息地的改变对黑颈鹤的空间利用造成较大的影响, 随着明水面由南向北退却,黑颈鹤的活动区域也随之移动。 3) 黑颈鹤对各栖息地具有选择性。使用欧几里德距离法分析表明黑颈鹤偏 好浅水沼泽和湿草甸,而回避耕地和干草地。这种偏好性不随季节而改变。 4)通过卫星跟踪发现:黑颈鹤具有相似的春季和秋季迁徙路线,但花费的 时间差异较大,春季时仅需1~2 天,而秋季时则花费了1~20 天。在迁徙过程 中,黑颈鹤通过山区时,沿河流飞行,在高原面上则顺低谷迁徙,迁徙中回避海 拔较高的高山,而多沿海拔较低的山谷飞行,在翻越高山时也选择较低的山隘口 通过。 根据研究的结果,提出如下保护建议:将黑颈鹤的核心利用区划为保护区的 核心区;重点保护浅水沼泽栖息地,在越冬期应该稳定保持一定面积的沼泽;规 范旅游管理,减少游客对黑颈鹤造成的干扰;开展家猪对湿地影响的研究,确立 合适的散养数量。
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This study consisted of sampling benthic algae at 32 sites in the Gangqu River, an important upstream tributary of the Yangtze River. Our aims were to characterize the benthic algae communities and relationships with environmental variables. Among the 162 taxa observed, Achnanthes linearis and Achnanthes lanceolata var. elliptica were the dominant species (17.10% and 14.30% of the total relative abundance, respectively). Major gradients and principal patterns of variation within the environmental variables were detected by principal component analysis (PCA). Then non-metric multidimensional scaling (NMS) divided all the sites into three groups, which were validated by multi-response permutation procedures (MRPP). Canonical correspondence analysis (CCA) indicated that three environmental variables (TN, TDS, and TP) significantly affected the distribution of benthic algae. Weighted averaging regression and cross-calibration produced strong models for predicting TN and TDS concentration, which enabled selection of algae taxa as potentially sensitive indicators of certain TN and TDS levels: for TN, Achnanthes lanceolata, Achnanthes lanceolata var. elliptica, and Cymbella ventricosa var. semicircularis; for TDS, Cocconeis placentula, Cymbella alpina var. minuta, and Fragilaria virescens. The present study represents an early step in establishing baseline conditions. Further monitoring is suggested to gain a better understanding of this region.
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Gymnocypris przewalskii (Kessler 1876) is an endangered and state-protected rare fish species in Qinghai Lake, China. To further understand the life history and distribution of this fish, five surveys were carried out in Qinghai Lake between 2002-2006. Results of these surveys indicate that fishes were predominantly distributed about 2 m under the surface. In July, significant differences in fish density were found between surface and bottom layers (P = 0.001), and/or between middle and bottom layers (P = 0.025). Fish density was the greatest in the surface layer. In August and October, no significant differences were found between the different layers, but the bottom layer had a greater fish density. Furthermore, there were very large differences among different zones in fish distribution density. Differences in horizontal distribution were not significantly correlated to factors such as water depth and inshore distance, possibly because of very low and uniform fish density. Feeding, changes in water temperature, over-wintering and spawning appeared to influence fish distribution. Hydroacoustic estimates of G. przewalskii biomass in Qinghai Lake increased significantly between 2002 and 2006. We attribute this increase to the management measures put in place to protect this species.
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Investigations of protozoa were carried out during four surveys of East Dongting Lake, China. A total of 160 protozoan species belonging to 71 genera was identified, of which 53 were flagellates, 37 sarcodines, and 70 ciliates. Among them, Peritrichida (32.6% of frequency), Arcellinida (16.2%), Volvocales (13.61/6), Peridiniales (13.1%), and Chrysomonadales (9.1%) were the main groups and contributed to 84.5% of the overall species. Ciliates were mainly composed of sessile species and small species. The total protozoan abundance varied from 2,400 cells L-1 to 20,250 cells L-1. The highest protozoan abundance occurred in spring; the lowest number was in autumn. The highest abundance of ciliates occurred in spring and winter, whereas flagellates developed the highest abundance in,summer and autumn. Pearson correlation analysis and linear regressions indicated that chlorophyll a and water velocity were the main factors affecting ternporal and spatial variations of the protozoan abundance.
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The spatial distribution and morphological diversity of virioplankton were determined in Lake Donghu which contains three trophic regions: hypertrophic, eutrophic and mesotrophic region. Virioplankton abundance measured by transmission electron microscope (TEM) ranged from 7.7 x 10(8) to 3.0 x 109 ml(-1), being among the highest observed in any natural aquatic system examined so far. The spatial distribution of virioplankton was correlated significantly with chlorophyll a concentration (r = 0.847; P < 0.01) at the sampling sites in Lake Donghu. 76 morphotypes were observed. Most morphotypes have tails, belonging to Siphoviridae, Myoviridae and Podoviridae. The majority of tailed phages in the lake were Myoviridae. Morphotypes which were rarely reported, such as prolate-headed virus-like particles, lemon-shaped virus-like particle, and viruses resembling Tectiviridae and Corticoviridae were all observed in the lake. It is concluded that the high viral abundance might be associated with high density of phytoplankton including algae and cyanobacteria. There was high viral diversity in this eutrophic shallow lake. In addition, cyanophage represented an important fraction of the virioplankton community in Lake Donghu. (c) 2006 Elsevier SAS. All rights reserved.
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The spatial pattern of the small fish community was studied seasonally in 1996 in the Biandantang Lake. Based on plant cover, the lake was divided into five habitats, arranged in the order by plant structure complexity from complex to simple: Vallisneria spiralis habitat (V habitat), Vallisneria spiralis-Myriophyllum spicatum habitat (V-M habitat), Myriophyllum spicatum habitat (M habitat), Nelunbo nucefera habitat (N habitat), and no vegetation habitat (NV habitat). A modified popnet was used for quantitative sampling of small fishes. A total of 16 fish species were collected; Hypseleotris swinhonis, Ctenogobius giurinus, Pseudorasbora parva, Carassius auratus and Paracheilognathus imberis were the five numerically dominant species. In both summer and autumn, the total density of small fishes was about 10 ind m(-2). Generally, Ctenogobius giurinus, a sedatory, benthic fish, was distributed more or less evenly among the five habitats, while the other four species had lower densities in the N habitat and NV habitat, which had the simplest structures. The distribution of the small fish species showed seasonal variations. In winter, most species concentrated in the V habitat, which had the most complex structure. In spring, the fish had low densities in the N and NV habitat, and were more or less evenly distributed in the other habitats. In summer, the fish had a low density in the NV habitat, and were evenly distributed in the other habitats. In autumn, the fish had higher densities in the V-M and M habitats than in the others. Generally, spatial overlaps between the dominant species were higher in winter than in the other seasons. It was suggested that the variations in the importance of predation risk and resource competition in habitat choice determined the seasonal changes of spatial patterns in the small fishes in the Biandantang Lake.
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Science & Technology Basic Work Program of China: Scientific Survey of the Middle-lower Reaches of Lantsang River and the Great Shangri-La Region [2008FY110300]; National Basic Research Program of China (973 Program): Ecosystem Services and Ecological Safety of the Major Terrestrial Ecosystems of China [2009CB421106]; National Natural Science Foundation of China [30670374]; EU ; European Commission, DG Research [003874]
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The relationships between ecological diversity and ecosystem functions such as stability and productivity have long been debated and have no final conclusion until now. It is ignored that the debate should be firstly based on the same diversity index, which should be theoretically complete, and on same observation scale. For the issue on the scale of ecotope observation, ecosystems should be distinguished according to intensity of human disturbance. For the issue on the scale of species observation, either number diversity or biomass diversity should be identified. This paper takes grassland ecosystems located within the Bayin Xile grassland of Xilin Gol League of Inner Mongolia Autonomous Region as an example to analyze effects of different diversity indices and spatial scales on the conclusions of ecological diversity and its relationships with ecosystem functions. The analysis results both on the scale of ecotope observation and on the scale of species observation show that different diversity indices might give different conclusions and spatial resolution has a great effect on the relative conclusions. (c) 2005 Elsevier B.V. All rights reserved.
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We obtained four phases of land cover spatial data sets by interpreting MSS images of middle and late 1970s and three phases of TM images of late 1980s, 2004 and 2008 based on field investigation in Three Rivers' Source Region. We analyzed the temporal and spatial characteristics of land cover and macro ecological changes in Three Rivers' Source Region in Qinghai-Tibet plateau since middle and late 1970s. Indicated by land cover condition index change rate and land cover change index, land cover and macroscopical ecological condition degenerated (7090 period Zc -0.63, LCCI -0.58)-obviously degenerated (9004 period, Zc -0.94, LCCI -1.76)-slightly meliorated (0408 period, Zc 0.06, LCCI 0.33). This course was jointly driven by climate change, grassland stocking pressure and implement of ecological construction project.
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The abundance of anchovy Engraulis japonicus larvae, >20 mum ciliates, copepod eggs and nauplii, and microzooplankton herbivorous activity were studied in the Yellow Sea in June 2000. Anchovy juveniles and larvae were found in only 6 of the 19 stations sampled. The ciliate communities were dominated by 2 species: Laboea strobila and Strombidium compressum. In the surface waters, the abundance of L. strobila ranged between 0 and 560 ind. l(-1). S. compressum only appeared at Stns 15 to 18 (20 to 3300 ind. l(-1)). L. strobila was found mainly in the top 20 m. The abundance of L. strobila was less than 50 ind, l(-1) in waters deeper than 25 m. S, compressum showed subsurface abundance peaks at the salinity abnormality. Tintinnids occurred occasionally with abundance lower than 100 ind. l(-1), The total ciliate abundance fell in the range of 40 to 3420 ind. l(-1). The ciliate biomass in the surface water and the water column ranged between 0,15 and 6.76 mug C l(-1) and 0.4 and 134.4 mg C m(-2), respectively, In the surface waters, the abundance of copepod eggs and nauplii ranged from 0,3 to 3.1 and 1,1 to 15.6 ind, l(-1), respectively. The average abundance of copepod eggs and nauplii in 4 depth (0, 5, 10 and 20 m) fell in the range of 0.2 to 2.8 and 1.0 to 29.4 ind. l(-1), respectively. As a food item of the E. japonicus post-larvae, the abundance of copepod nauplii and eggs appeared to be low. The abundance peaks of ciliate and E, japonicus post-larvae coincided. Although not found in the gut of E, japonicus post-larvae, aloricate ciliates might be ingested by first-feeding anchovy larvae, preventing initial starvation and prolonging the time to irreversible starvation. On the basis of dilution experiments with positive microzooplankton grazing rates, microzooplankton grazed at rates of 0 to 0.61 d(-1). Grazing pressure of microzooplankton on chlorophyll a standing stock (P-i) and potential chlorophyll a primary production (P-p) were 17 to 46% and 35 to 109% d(-1), respectively.