Social network analysis and network connectedness analysis for industrial symbiotic systems: model development and case study     

Yan ZHANG  Hongmei ZHENG  Bin CHEN  Naijin YANG 《Frontiers of Earth Science》2013,(2)

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基于EOF分析的三江源区植被覆盖变化时空分布特征   总被引：1，自引：0，他引：1  

龚斌  甘小莉  刘伟玲  张林波  陈婷  巢世军 《地学前缘》2013,20(3):234-239

基于遥感图像1999-2010 年SPOT VEGETATION NDVI 数据,利用经验正交函数(EOF)分析方法,研究了近12a来三江源区植被变化的时空分布特征。结果显示近12a来源区植被覆盖呈整体增加趋势：(1)第一特征向量(方差贡献率为45.62%)及对应时间系数表明源区植被覆盖逐渐增加,且增速加快;(2)第二特征向量(方差贡献率为9.77%)及对应时间系数表明东南部和中部植被变化情况以退化为主,而东北部和西南部植被变化情况以增加为主。  相似文献   

农田蒸散双层模型及其在干旱遥感监测中的应用   总被引：60，自引：4，他引：60  

隋洪智  田国良  李付琴 《遥感学报》1997,1(3):220-224

该文建立了在部分植被条件下估算农田蒸散的双层模型，利用此模型和ＮＯＡＡ－ＡＶＨＲＲ数据对黄淮海平原春季旱情进行了评估，并做出了干旱及蒸散分布图。对双层模型和单层模型的估算结果进行了比较，结果表明在部分植被条件下双层模型估算的精度要高。  相似文献   

Submerged vegetation of Lakes Sumner,Marion, Katrine,Taylor, and Sheppard in Canterbury,New Zealand     

Maryd De Wemton  John S. Clayton  Rohan D. S. Wells  Chris C. Tanner  Suzanne T. Miller 《新西兰海洋与淡水研究杂志》2013,47(2):145-151

The submerged vegetation of Lakes Sumner, Marion, Katrine, Taylor, and Sheppard was surveyed in May 1987. These high‐altitude lakes lie at c. 600 m a.s.l., within the largely unmodified upper Hurunui catchment. Submerged vegetation was diverse and included numerous short shallow‐water species, dense swards of Isoetes alpinus, low covers of taller native vascular plants, and charophyte meadows beyond the depth limit of vascular plants to a maximum of 15 m. A sparse deepwater bryophyte community was observed from 11 to 32 m depth in Lake Sumner. Displacement of native vegetation by dense growths of the adventive oxygen weed Elodea canadensis over mid‐depths of 3–6 m was noted in all lakes, except Lake Marion.  相似文献   

新疆山地-绿洲-荒漠系统及其气候特征   总被引：13，自引：3，他引：10  

孙洪波  王让会  张慧芝  黄俊芳  赵振勇 《干旱区地理》2005,28(2):199-204

在位于中国西北内陆干旱区的新疆,发育着大量的山地-绿洲-荒漠系统,山地系统是干旱区水资源的形成区,也是重要的矿质营养库和生物种质资源库,绿洲系统是生产力相对较高的区域和人类赖以生存和发展的中心,而荒漠系统则是干旱区面积广阔和环境相对恶劣的区域。地貌类型与气候特征决定耦合类型的基础和框架,水文特征决定耦合类型的空间格局,植被类型反应耦合类型的外貌。通过对新疆山地、绿洲、荒漠三个子系统结构与功能进行了分析,并结合新疆近40年气候变化的特点和规律,来探讨中亚干旱区山地-绿洲-荒漠系统的特征。  相似文献   

Observations on Chatham Rise currents   总被引：2，自引：2，他引：0  

M. J. Winterbourn  J. S. Rounick  B. Cowie 《新西兰海洋与淡水研究杂志》2013,47(3):321-328

New Zealand stream ecosystems differ from many of their North American counterparts, on which general stream ecosystem models are based, in several ways. In New Zealand, large particle detritivores (shredders) are poorly represented, and the dominant invertebrates are browsers which feed on fine particulate organic matter and stone‐surface organic layers. In contrast with the river continuum concept of Vannote et al. (Canadian Journal of Fisheries and Aquatic Sciences 37: 130–137, 1980), representation of functional feeding groups shows little change downstream and a temporal continuum of synchronous species replacements is not found. Many common benthic invertebrates are ecologically flexible species with poorly synchronised life histories. These differences appear to be associated with the non‐retentive, climatically unpredictable nature of the stream environment. The idea that stream communities are highly structured entities is questioned, as is the generality of the river continuum concept.  相似文献   

Ecology of rocky reef fish of northeastern New Zealand: 50 years on     

GP Jones 《新西兰海洋与淡水研究杂志》2013,47(3):334-359

Abstract

This review examines the history and current understanding of the ecology of rocky reef fishes in northeastern New Zealand, marking the fiftieth anniversary of the Leigh Marine Laboratory. The cumulative number of publications increased steadily to c. 180 by 2012. Most attention has been on the snapper (Pagrus auratus, f. Sparidae), the largest in size and economically most important species, and on triplefins (Tripterygiidae), the smallest in size and most diverse family. A strong quantitative school emerged in the 1980s, a period when there was little research on temperate reef fishes elsewhere. A ‘bottom-up’ view of the effects of habitat structure on fish emerged, identifying the key roles of depth, topography and macroalgae. By 2000, attention shifted to using marine reserves as laboratories for ecological research. A ‘top-down’ view of fish as predators emerged, documenting cascading effects on prey communities and habitats. The two different viewpoints have not yet been integrated. Research gaps, including population connectivity and climate change, represent major challenges for the next 50 years.  相似文献   

Use of particle-size data to predict potential pelagic-fish yields of some southern African areas     

《African Journal of Marine Science》2013,35(1):119-128

A particle-size spectrum model is used to estimate standing stocks of some pelagic fish from measurements of phytoplankton chlorophyll in two exploited regions in southern Africa (southern Benguela and off South West Africa/Namibia) and in two unexploited regions (the Agulhas Bank and off the eastern Cape Province). The model is based on the assumption that equal biomasses occur in logarithmically equal size classes in the pelagic marine environment. Phytoplankton, with an equivalent spherical diameter ranging from 1 to 128 μm, occupy 21 size classes on the logarithmic scale. Two different size ranges are assumed for some commercial, pelagic fish species, equivalent to exploitation with two different purse-seine mesh sizes. A mesh of 12,7 mm would catch 8 size classes of pilchard, horse mackerel and anchovy whereas a mesh of 32 mm would catch only 3,3 size classes of pilchard and horse mackerel. From the model, the potential biomass of these commercial pelagic fish is estimated, after allowing for the presence of other commercial and non-commercial fish and other taxa in the exploited size range. Total pelagic fish production is estimated by assuming constant turnover rates of 1·y^?1 and 1,5·y^?1 when exploited with 32 and 12,7 mm mesh nets respectively. Consideration of the maximum and mean reported catches in the exploited areas indicates that only some 25 per cent of pelagic fish production is exploitable by man. On this basis, the unexploited Agulhas Bank region may yield some 400 000 metric tons (wet) of pelagic fish of the species considered, and the East Coast region some 90 000 tons. Exploitation in these regions cannot be recommended, because the Agulhas Bank is an important spawning ground for many pelagic species, and the fish in both regions probably act as a reserve buffer for the heavily exploited pelagic resource of the Western Cape.  相似文献   

Nutritional condition of fish larvae in South African estuaries: an appraisal of three biochemical methods     

《African Journal of Marine Science》2013,35(3):377-386

Estuaries are exposed to a number of threats and many South African estuarine systems are functionally and structurally altered. The extent to which fish are affected by these alterations is not fully understood. The estuarine round herring Gilchristella aestuaria is an appropriate species to use when examining such effects. The most widely used approaches to evaluating the nutritional condition of fish larvae are based on biochemical methods. In order to identify the most suitable technique for assessing body condition of fish larvae in estuaries, the nutritional condition of post-flexion larvae of G. aestuaria from the Sundays and Kariega estuaries on the south-east coast of South Africa was evaluated using three different biochemical techniques: (i) total lipid content analysis and the triacylglycerol/cholesterol (TAG/CHOL) ratio; (ii) protein content analysis; and (iii) the RNA/DNA ratio. Results from techniques (ii) and (iii) revealed that G. aestuaria larvae from the Kariega Estuary were in better condition than larvae from the Sundays Estuary, probably due to a recent plankton bloom. It is concluded that the individual RNA/DNA ratio can provide a reliable, sensitive and cost-effective method to assess the immediate effects of environmental changes on the nutritional condition of estuarine fish larvae.  相似文献   

Parasites in tarakihi (pisces: Cheilodactylidae) from three areas around New Zealand     

C. M. Vooren  D. Tracey 《新西兰海洋与淡水研究杂志》2013,47(3):499-509

The parasite faunas of tarakihi Cheilodactylus macropterus (Bloch & Schneider) from East Cape, Tasman Bay, and the Chatham Islands were compared. A total of seven parasite species were found of which four were recorded in tarakihi for the first time: Nybelinea sp., Hepatoxylon trichiuri (Holten), Echinorhynchus sp. and Clavellodes sp. The last two of these were new records for New Zealand. The other parasites were: Contracaecum sp., Anisakis sp. and Aethon garricki Hewitt. The nematode Anisakis sp. and the copepods Aethon garricki Hewitt and Clavellodes sp. were the commonest parasites.

Incidence and intensity of Anisakis sp. were high off the Chatham Islands, moderate off East Cape, and low in Tasman Bay. These differences in infestation were truly regional and were only partially caused by differences in age composition of the fish samples. Intensity of infestation with Anisakis sp. was related to age of fish off the Chatham Islands, but not in the other two areas, and this probably reflects regional differences in the diet of the tarakihi.

Incidence of Clavellodes sp. was low in Tasman Bay. This parasite was absent from the other two areas, which either may indicate a true regional difference in the distribution of the parasite or may be caused by differences in the age composition of the samples.

Incidence of Aethon garricki was moderate in Tasman Bay and off East Cape, but this parasite did not occur in the Chatham Islands tarakihi. Thus, tarakihi populations from three widely separated areas differed from each other in the incidence and intensity of at least one of the three commonest parasites.  相似文献