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431.
Journal of Geographical Sciences - The spatiotemporal landscape heterogeneity implies multiple biodiversity mechanisms across scales, and the cross-disciplinary studies between landscape ecology... 相似文献
432.
An online spatial biodiversity model (SBM) for optimized and automated spatial modelling and analysis of geospatial data is proposed, which is based on web processing service (WPS) and web service orchestration (WSO) in parallel computing environment. The developed model integrates distributed geospatial data in geoscientific processing workflow to compute the algorithms of spatial landscape indices over the web using free and open source software. A case study for Uttarakhand state of India demonstrates the model outputs such as spatial biodiversity disturbance index (SBDI) and spatial biological richness index (SBRI). In order to optimize and automate, an interactive web interface is developed using participatory GIS approaches for implementing fuzzy AHP. In addition, sensitivity analysis and geosimulation experiments are also performed under distributed GIS environment. Results suggest that parallel algorithms in SBM execute faster than sequential algorithms and validation of SBRI with biological diversity shows significant correlation by indicating high R2 values. 相似文献
433.
在大气圈、水圈、岩石圈和生物圈等多圈层相互作用下,全球范围内海洋生物多样性中心的地理位置、物种组成结构和优势度都呈动态变化.迄今,海洋生物多样性中心的形成与演变机制在生态、遗传和分子等层面正逐步得到解析.在生态层面,学界涌现出了物种形成中心、物种汇聚中心、物种重叠中心和物种保存中心等重要科学假说,解析了生物多样性分布格... 相似文献
434.
There are 3048 species offish occurring in the China Seas (CS), of which at least 2321 species are found in the South China Sea (SCS), belonging to 35 orders, 236 families and 822 genera. The fish species diversity is analyzed in this paper based on biogeography, biostatisties, fishing methods, etc. It is found that the regional environment, especially biological factors, plays an important role in the distribution of faunas, and there are two fish faunas in the SCS, one in the north and another in the center and south. This regional division is of value for sustainable fishery production and efficient management of fishery resources. 相似文献
435.
Evaluating sustainability of community endeavours in an Indian floodplain wetland using multi‐criteria decision analysis 下载免费PDF全文
The floodplain wetlands of Ganga‐Ichamati interfluves in India have become severely degraded due to incessant, unsustainable utilization practices and lack of community awareness. In spite of the wetlands being the prime source of livelihood for millions, no comprehensive management strategy to accommodate the diverse aspirations and priorities of different users has been implemented for the wetlands to date. In this paper, the authors applied a framework of criteria and indicators to evaluate the status of sustainability achieved by community endeavours in one such wetland. The priorities, consumption patterns and contributions towards wetland conservation of major user groups functioning in that area were assessed by the framework developed through participatory multi‐criteria decision analysis. Results show the deteriorating status of the wetland at present regarding biodiversity conservation and livelihood generation. Fishing activities were identified as the dominant utilization option here followed by agriculture. The paper further explored the preferred alternative utilization strategies for achieving sustainability. Effectiveness of the developed framework in evaluating the extent of sustainability achieved in community endeavours was also highlighted in this context. 相似文献
436.
About 52% of the world's population now lives in urban areas, and 41% of urban land in developed countries is used for residential areas. The amount and quality of residential green space, an important element in urban residential infrastructure, is closely correlated to city dwellers' quality of life. The quality of green spaces is not only closely correlated to the ecosystem services they provide, but also to their disservices. In order to (i) examine how plant diversity and plant traits vary in different residential areas, (ii) determine the main socio-economic factors driving plant trait variations across different residential areas, and (iii) provide an overview on selected ecosystem services and disservices related to plant diversity, we investigated the flora and socio-economic properties of 83 residential areas in Beijing, China. We found a total of 369 plant species belonging to 99 families and 150 genera. With respect to plant traits, there were 90 annual species, 174 alien species, 169 pollen allergenic species, and 133 species with edible or pharmaceutical value. The number of perennial, alien, ornamental and edible plant species was largest in residential areas completed in the 1990s. The number of allergenic species was highest in residential areas completed prior to 1980. The Simpson, Shannon and Pielou indices for trees and shrubs were highest in areas completed in the 1990s, while those same indices for herbs were highest in residential areas completed prior to 1980. General Linear Model analyses revealed that richness increased with increasing housing price across all groups of species. Principal Component Analysis indicated that housing price and floor-area ratio are the variables that positively correlate with species richness for all groups of species. 相似文献
437.
以云龙天池湖泊为研究对象,通过分析不同深度表层硅藻样品的生物多样性以及100年来硅藻生物多样性的变化特征,探讨硅藻生物多样性与水深变化之间的关系.虽然硅藻组合随水深发生了明显的变化,浅水区底栖硅藻占优势,深水区浮游硅藻占优势,但是不同深度表层样品中硅藻的属种数(简单分异度)基本相同,硅藻种群的生物多样性也没有发生显著的趋势性变化.这主要是由于硅藻各属种在不同深度的权重互补,导致云龙天池硅藻的多样性在湖泊的不同深度变化不大.近百年来的湖泊沉积速率显示,自1960年前后,湖泊水位在波动中逐步升高,但是硅藻种群的生物多样性并没有发生相应的变化.以上研究结果说明,云龙天池硅藻种群的生物多样性,不管是在时间上,还是空间上,与水深变化均无明显相关性. 相似文献
438.
This is the first record of live (stained) deep-sea benthic foraminifera in the 850 m deep silled Hardangerfjord, the second deepest fjord in Western Norway. Estimates of organic carbon flux (∼2.5 g Cm−2 y−1) show that the fjord-values are comparable to similar depths on the continental slope. Accordingly, although these first samples only provide relative abundance data, the low proportion of live to dead individuals in the top cm of the sediment suggests a low foraminifera biomass. Another similarity with the deep sea is that the abiotic environment of the deep basins is stable even though the deepest basins are isolated from the open deep sea by the continental shelf and sills in the outer parts of the fjord suggesting that the deep-sea species are introduced as propagules during deep-water renewals. There is evidence of an increase in dissolution of fragile calcareous tests (e.g., Nonionella iridea) especially in the innermost part of Hardangerfjord since the 1960s and this has led to a relative increase in dead agglutinated assemblages. The presence of larger forms with tests >1 mm provides substrata for the attachment of smaller forms and therefore an increase in species diversity. Indeed, the diversity is comparable both to that of the open deep sea and that of reported macrofauna from the same sites, reflecting similar ecological status. Holtedahl (1965) suggested that there may be some down-slope transport of sediment into the deep basins with the deposition of turbidites. Despite some evidence of transport, no major recent disturbance due to turbidite deposition seems to have occurred and hence Hardangerfjord presents a unique environment with elements of deep-sea faunas in a land-locked setting. 相似文献
439.
全球变化对陆地生态系统的影响研究 总被引:3,自引:0,他引:3
在对前人研究成果分析总结的基础上,介绍了大气温室气体含量增加、气候变暖、海平面上升等全球变化的事实,认为全球变化很大程度上取决于自然的变异,但人为活动也是不可忽视的主要原因.从水热平衡失调、气候异常、海平面上升、快速荒漠化和生物多样性减少等方面探讨了全球变化对农业生态系统中粮食种植、畜牧业生产、农业自然灾害的影响,森林生态系统、水生态系统和生物多样性的变化,以及全球变化对陆地生态系统影响的地域差异,不同生态系统对于全球变化响应的变化.最后探讨了今后研究面临的形势和任务. 相似文献
440.
Large igneous provinces (LIPs) are considered a relevant cause for mass extinctions of marine life throughout Earth’s history. Their flood basalts and associated intrusions can cause significant release of SO4 and CO2 and consequently, cause major environmental disruptions. Here, we reconstruct the long-term periodic pattern of LIP emplacement and its impact on ocean chemistry and biodiversity from δ34Ssulfate of the last 520 Ma under particular consideration of the preservation limits of LIP records. A combination of cross-wavelet and other time-series analysis methods has been applied to quantify a potential chain of linkage between LIP emplacement periodicity, geochemical changes and the Phanerozoic marine genera record. We suggest a mantle plume cyclicity represented by LIP volumes (V) of V = ?(350–770) × 103 km3 sin(2πt/170 Ma) + (300–650) × 103 km3 sin(2πt/64.5 Ma + 2.3) for t = time in Ma. A shift from the 64.5 Ma to a weaker ~28–35 Ma LIP cyclicity during the Jurassic contributes together with probably independent changes in the marine sulfur cycle to less ocean anoxia, and a general stabilization of ocean chemistry and increasing marine biodiversity throughout the last ~135 Ma. The LIP cycle pattern is coherent with marine biodiversity fluctuations corresponding to a reduction of marine biodiversity of ~120 genera/Ma at ~600 × 103 km3 LIP eruption volume. The 62–65 Ma LIP cycle pattern as well as excursion in δ34Ssulfate and marine genera reduction suggest a not-yet identified found LIP event at ~440–450 Ma. 相似文献