Habitat characteristics and spatial arrangement affecting the diversity of fish and decapod assemblages of seagrass (Zostera marina) beds around the coast of Jersey (English Channel)     

Emma L. Jackson  Martin J. Attrill  Malcolm B. Jones 《Estuarine, Coastal and Shelf Science》2006,68(3-4):421

Recent research and management plans for seagrass habitats have called for landscape level approaches. The present study examines the spatial utilisation of subtidal seagrass beds by fish and decapods around the coast of Jersey (49°N 02° W). A hierarchical scale of landscape configuration and the plant characteristics of eight seagrass beds were measured and the contributions of these variables as predictors of the properties of the fish and decapod assemblages were evaluated using multiple linear regression models. The results indicated that total diversity had a negative relationship with transect heterogeneity and total species number had a weak negative association with increasing fragmentation. Both total diversity and total species number showed a positive relationship with depth. In fact, in all models of species number and densities, values were higher in deeper seagrass beds. Total decapod density increased with aggregation of seagrass patches within a landscape. In addition to landscape configuration, smaller-scale structural changes in both canopy height and epiphyte load appeared to influence densities of decapod crustaceans. At night, fewer patterns could be explained by the independent variables in the model.  相似文献   

云贵高原晚新生代孢粉植物群与环境变迁   总被引：8，自引：5，他引：8  

童国榜  羊向东 《海洋地质与第四纪地质》1994,14(3):91-104

本文依据２０多个剖面（钻孔）近７００个样品的孢粉资料及古地磁极性年表建立了云贵高原４Ｍａ以来的孢粉时间序列，并划分了四个区域孢粉组合带，１７个孢粉组合亚带。依据孢粉混杂堆积的出现，认为云贵高原的上升始于２．８ＭａＢ．Ｐ．，加剧于０．８ＭａＢ．Ｐ．前后。前期地形相对高度＜１０００ｍ，后期相对高度达１５００ｍ；地貌经历了开阔盆地－低洼盆地－山地湖盆－高山湖盆的演化。气候经历了古季风、现代季风的发展过程  相似文献   

Seagrass landscape-scale changes in response to disturbance created by the dynamics of barrier-islands: A case study from Ria Formosa (Southern Portugal)     

A.H. Cunha  R.P. Santos  A.P. Gaspar  M.F. Bairros 《Estuarine, Coastal and Shelf Science》2005,64(4):636-644

This study documents long-term changes of a Zostera noltii landscape induced by a natural cyclic event in a coastal lagoon. The barrier-islands forming this system are very dynamic with drifting movements controlling ecological patterns and processes occurring in this area. Changes in the areal extent of the Z. noltii meadows were assessed using historical aerial photographs from 1940, 1980, 1989, 1996 and 1998. Landscape indices such as total patch area (TA), mean patch size (MPS), number of patches (NP), mean shape coefficient of variation (CV) and landscape fractal dimension (D) were calculated for each year and related to an index of disturbance intensity. The spatial distribution of the Z. noltii meadows varied greatly during the studied period and changes observed were related to the disturbance created by the barrier-islands' spatial dynamics. After an artificial inlet relocation the Z. noltii area, number of patches, patch mean size and coefficient of variation decreased. The fractal dimension of the Z. noltii landscape increased by 50% showing that besides a decrease in total area, number of patches, and patch mean area, patch fragmentation was an important consequence of this anthropogenic disturbance.Seagrass natural distribution patterns changed in response to natural and human-induced activities. This study emphasizes the importance of the landscape approach and the historical perspective when studying seagrass changes and the importance of taking into consideration long-term changes in seagrass landscapes to avoid confusion between man-induced effects with natural cyclic events.  相似文献   

Experimental activities that intentionally perturb the marine environment: Implications for the marine environmental protection and marine scientific research provisions of the 1982 United Nations Convention on the Law of the Sea     

Philomène A. Verlaan 《Marine Policy》2007

The global community's ability to assess the environmental effects of marine scientific research (MSR) as required by the 1982 United Nations Convention on the Law of the Sea's (UNCLOS) marine environment provisions (MEP) is limited, as shown by experimental activities that intentionally manipulate the marine environment. Such work enhances knowledge of the ocean, but it may also have significant environmental effects. This growing use of the ocean as a laboratory has global scientific, environmental, legal and policy implications. Examined here is the relationship between the MSR and the MEP provisions of UNCLOS. International, science-driven guidelines are proposed.  相似文献   

刍论大连湾底质地化环境   总被引：6，自引：0，他引：6  

鲍永恩  马嘉蕊 《海洋科学》1990,(4)

本文根据1987年的调查资料,总结阐述了大连湾底质地化环境诸要素的分布规律及其特征,运用相关分析法,通过多元回归计算求得了诸要素之间的关系。经过综合因素分析,得出了大连湾氧化还原环境分区、还原环境的成因及发展趋势。  相似文献   

长岛养殖扇贝丰,欠原因的初步探讨   总被引：1，自引：0，他引：1  

王从敏  牛世奎 《海洋湖沼通报》1993,(3):94-100

通过对长岛扇贝养殖环境两年(1989、1990)监测及历史资料的初步分析研究,得出了影响长岛养殖扇贝丰欠的主要因子有:1)长岛地区的降水量;2)海水中浮游植物含量;3)海水盐度。建立了适合长岛水域的模糊综合评判关系式用以综合评判长岛的扇贝养殖环境及其与养殖扇贝丰、欠之间的关系。  相似文献   

对应分析方法在粤西水东湾动力沉积环境分析的应用     

陈子燊 《热带海洋学报》1991,(1)

本文以粤西水东湾表层沉积物样品的粒度分布为基本数据,使用对应分析方法并结合地形与波流特征,分析了海湾动力沉积环境。分析结果表明,海湾现代沉积环境可划分为4个动力沉积区。  相似文献   

水成沉积与风成沉积及古土壤的磁组构特征   总被引：14，自引：2，他引：14  

张家强  李从先  丛友滋 《海洋地质与第四纪地质》1999,19(2):85-94

晚第四纪水成沉积、风成沉积、古土壤等的磁组构研究表明,不同成因的沉积物具有明显不同的磁组构特征。一般地,水成沉积的体积磁化率Ｋ受物源和水动力因素控制,Ｐ和Ｆ均＞１．０２,ｑ＜０．５;风成沉积的Ｋ受物源控制,内陆黄土的Ｋ明显高于沿海黄土及海岸风沙Ｋ,Ｐ和Ｆ均＜１．０２,ｑ的平均值＞０．５５;古土壤的Ｋ受母质沉积类型和成土环境的氧化还原条件控制,内陆古土壤的Ｋ偏高,沿海古土壤的Ｋ偏低,内陆古土壤的Ｋ远高于沿海古土壤的Ｋ,Ｐ和Ｆ均＜１．０２,ｑ的平均值在０．５左右。运用典型沉积的磁组构特征对比分析未知沉积物,可以得到未知沉积物的物源、沉积过程和环境信息。  相似文献   

从山羊寨哺乳动物化石看柳江盆地洞穴堆积的时代与环境   总被引：3，自引：0，他引：3  

牛平山  张燕君  法蕾 《海洋地质与第四纪地质》2003,23(2):117-122

山羊寨洞穴堆积是河北省秦皇岛“柳江盆地地质遗迹自然保护区”众多溶洞的洞穴堆积之一，其中含有大量的哺乳动物化石。经发掘整理与鉴定，采用生物地层学和哺乳动物生活习性对比分析方法，确定其时代为Qp^2.3，晚于辽宁营口“金牛山下组动物群”，早于河北“迁安爪村动物群”和内蒙古“萨拉乌苏动物群”，其特征反映了中国华北与东北过渡地带中更新世晚期至晚更新世早期的哺乳动物面貌，并反映出当时区内森林、森林草原、草原和水域条件等生态环境的多次时空变化。如此众多哺乳动物化石的发现增加了保护区遗迹资源的多样性和保护价值；为该区洞穴堆积的时代与沉积环境研究提供了依据；改变了区内洞穴堆积仅为中更新世地层的认识。  相似文献   

福清湾北部及其以东近岸海域沉积环境和沉积特征     

郑承忠 《台湾海峡》1997,16(4):386-392

本文对福清湾北部及其以东近岸海域的地质地貌，潮流和波浪等沉积环境因素，以及对沉积物和悬浮泥沙的粒度，矿物特征进行研究，认为福清湾为溺谷型的半封闭潮汐汊道海湾存在着较大的潮差和潮流流速，沉积物沿潮流方向呈东粗西细和岸边细、向海变粗的潮流分异特征，潮流控制着沉积物的布局，而属于潮控的浅海沉积环境。  相似文献