The Norwegian Nature Index – state and trends of biodiversity in Norway     

《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(5):241-249

The aim of the Norwegian Nature Index (NI) is to provide an overview of the state of biodiversity within and across major ecosystems. The index is composed of a series of indicators, each representing individual species or diversity measures. The indicators are standardized and scaled in relation to a reference state, and combined for ecosystems or geographical regions, to give a number between 1 (reference state) and 0 (seriously degraded biodiversity). In 2010, the state of biodiversity was highest in mountains, ocean, coastal waters, and freshwater (NI=0.69–0.80), intermediate for mires and wetlands (NI=0.55), and lowest for open lowlands and forests (NI=0.43–0.44). The NI increased 8–10% in freshwater and the ocean (bottom and pelagic) from 1990–2010, but decreased by>10% in open lowlands during the same period. Since its launch in September 2010, the Nature Index has been approved by the Ministry of Finance as an indicator for biodiversity in the set of sustainable development indicators and approved by the Ministry of Environment as an indicator of the state of major ecosystems.  相似文献   

Further planktonic algae of Auckland sewage treatment ponds and other waters     

A. Haughey 《新西兰海洋与淡水研究杂志》2013,47(2):245-261

Seventeen species of algae, newly recorded between 1965 and 1968 from sewage treatment ponds around Auckland City, are described together with another 11 species found in eutrophic waters of the area. These latter natural waters are often of a transient nature and usually heavily polluted in some way.

The genera recorded, with number of species (in brackets), are: Flagellata: Euglena (5); Lepocinclis (1); Phacus (3); Trachelomonas (1). Chlorophyceae (Volvocales): Chlamydomonas (1); Pteromonas (1); Pyrobotrys (1); Chloro‐gonium (1) (Chlorocoecales): Coelastrum (1); Tetrallantos (1); Closteriopsis (1) Scenedesmus (5). (Conjugates) : Closterium (3). Myxophyceae: Anabaena (1); Arthrospira (1); Oscillatoria (1).  相似文献   

The nature and engineering behavior of carbonate soils at Bombay High,India     

Manoj Datta  G. Venkatappa Rao  Shashi K. Gulhati 《Marine Georesources & Geotechnology》2013,31(4):307-341

Abstract

This paper presents the results of a laboratory investigation undertaken to study the nature of two submarine carbonate soils from Bombay High off the west coast of India, as well as to study the shear and plasticity behavior of their sand and silt‐clay fractions, respectively. Scanning electron micrographs reveal that the carbonate content in both soils is comprised primarily of nonskeletal particles of various types. X‐ray diffraction and infrared absorption analyses indicate that in one soil the carbonate fraction consists of calcite and aragonite minerals, whereas in the other soil dolomite is also present. The non‐carbonate fraction of both soils is comprised primarily of quartz and feldspar, and also some clay minerals. The nature of the carbonate fraction of the two soils indicates that they were formed by different depositional processes.

During drained triaxial shear the nonskeletal sand grains of both soils exhibit a lower degree of crushing when compared with that of the skeletal carbonate sands, and thus appear to be stronger foundation material.

Although the carbonate contents of the silt‐clay fractions of the two soils are similar, they exhibit markedly different plasticity characteristics . This is probably because of the microlevel cementation produced by carbonate material in one soil.

This study leads one to the conclusion that carbonate content alone should not be treated as a parameter which controls the engineering behavior of submarine soils; the nature and form of carbonate material must also be identified.  相似文献   

BIODIVERSITY AND LAND‐USE CHANGE IN THE AMERICAN MOUNTAIN WEST     

JEREMY D. MAESTAS  RICHARD L. KNIGHT  WENDELL C. GILGERT 《Geographical review》2001,91(3):509-524

ABSTRACT. Rural private lands in the Mountain West of the United States are undergoing a profound land‐use conversion, from agriculture to low‐density residential or exurban development, though little scientific study documents the ecological consequences of this change. Nongovernmental conservation organizations are working with ranchers to keep rangeland out of development and in ranching, ostensibly because these organizations believe that biodiversity is better protected on ranches than on exurban developments. We compared plant and wildlife communities across the principal rural land uses in the Mountain West: protection, livestock ranching, and exurban development. Native plant and faunal biodiversity was better maintained on ranches and protected areas than on exurban developments. Exurban developments favored species that were nonnative or adapted to human‐altered environments. The continued conversion of ranches to exurban development suggests a long‐term alteration of the region's natural heritage.  相似文献   

Contrasting patterns in the abundance of fish communities targeted by fishers on two coral reefs in southern Mozambique     

T Sancelme  J Goetze  S Jaquemet  MG Meekan  A Flam  AM Watts 《African Journal of Marine Science》2020,42(1):95-107

Coastal populations of maritime countries in eastern Africa rely on fish as a primary source of protein, but baseline information on the abundance of fish communities on these coastlines is often lacking. We used baited remote underwater video stations to compare the abundance and diversity of reef fishes targeted by fishing at two sites in southern Mozambique, one at Lighthouse Reef within the Bazaruto Archipelago National Park and the other to the south at San Sebastian Reef on the San Sebastian Peninsula. Fish that are known targets of fisheries (mostly small-scale and artisanal) had an abundance that was almost three-times greater at San Sebastian Reef (80.22 ind. h^–1 [SE 18.00]) than at Lighthouse Reef (29.70 ind. h^–1 [SE 8.91]). Similarly, there was greater mean species richness at San Sebastian Reef (38.74 species h^–1 [SE 2.79]) than at Lighthouse Reef (25.37 species h^–1 [SE 3.66]). The main drivers of targeted fish abundance were habitat and depth, with shallow (<15 m) and mixed reef areas having the greatest abundance and richness. More sampling was done over sand habitat at Lighthouse Reef, which likely led to the lower abundance and species richness observed at this site; however, that finding could also be attributable to the fact that protection is provided to only a section of available coral reef habitat in a small area. Nevertheless, fish community structure was comparable between the sites, with similar proportions of carnivores (78–81%), herbivores (12–14%) and omnivores (7–8%). Our findings highlight the variation in species abundance and assemblages of coral-reef fish targeted by fishing in Mozambique and emphasise the importance of localised environmental variables as a driver of these patterns. To ensure maximum protection of Lighthouse Reef fish communities, we recommend an extension of the no-take zone to include the entire reef complex.  相似文献   

Effects of epibionts on Sabellaria alveolata (L.) biogenic reefs and their associated fauna in the Bay of Mont Saint-Michel     

Stanislas Dubois  John A. Commito  Frdric Olivier  Christian Retire 《Estuarine, Coastal and Shelf Science》2006,68(3-4):635

Biogenic structures built by ecosystem engineers such as corals, bivalves, polychaetes, and sea grasses provide habitat for benthic vertebrates and invertebrates. The polychaete Sabellaria alveolata is an important foundation species whose reef structure adds topographic complexity and high levels of biodiversity to the otherwise low-relief, low diversity, soft-bottom environments in the Bay of Mont Saint-Michel, France, where the largest such reef formations in Europe are found. In this bay, reefs are being increasingly colonised by oysters (Crassostrea gigas) from local aquaculture operations and by green algae (Ulva sp.) due to the increasing inputs of nitrates from terrestrial origin. The purpose of this study was to investigate the possible impacts of epibiotic oysters and green algae on the S. alveolata population and reef community structure in the Bay of Mont Saint-Michel, France. Univariate and multivariate comparisons of macrofauna were conducted for five reef types: controls (no epibionts), low oyster density, high oyster density, green algae, and oyster and green algae. Results showed that all the three reef types with oysters had significantly higher species richness and diversity values than control and algae-only reef types. Pairwise ANOSIM and SIMPER comparisons of controls versus the four reef types with epibionts revealed that all three of the reef types with oysters were significantly different from controls, but there was no significant difference between controls and algae-only reef types. A striking feature of the reef comparisons is that no single species in this species-rich system contributed more than 8.86% to the dissimilarity between the reef types. Thus, k-dominance curves for species abundances were not effective in revealing differences among the reef types. Our results demonstrate that recent anthropogenic inputs of oysters affect the reef species assemblage more strongly than algal epibionts. In addition, epibionts, especially green algae, alter S. alveolata population structure, causing a reduction in new recruits that over the long run may cause significant damage to the reef structure itself. These results are a first step towards understanding anthropogenic threats to S. alveolata reefs and may be useful in the development of strategies for their protection and management.  相似文献   

The influence of offshore windpower on demersal fish   总被引：1，自引：0，他引：1  

Wilhelmsson  Dan; Malm  Torleif; Ohman  Marcus C. 《ICES Journal of Marine Science》2006,63(5):775-784

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大鹏澳浮游植物现存量和初级生产力及N∶P值对其生长的影响     

宋星宇  黄良民  张建林  尹健强  张俊彬  黄小平 《热带海洋学报》2004,(5)

2001年7月测定大鹏澳表层叶绿素a含量为2.61—19.87mg·m-3,初级生产力为404.08—1097.25mgC·(m2·d)-1,N∶P值远高于Redfield比值16。回归分析表明,该水域浮游植物的现存量或生长量并不受某个单一因子调控。在营养盐加富试验中,加入含有P系列的浮游植物增殖速度最快,揭示P是此时大鹏澳浮游植物的潜在限制因子。将大鹏澳浮游植物水样置于不同的N∶P值环境中进行实验,结果表明,浮游植物在N∶P值为30的梯度组中生物量最高,浮游植物生物多样性程度也最高,其次是N∶P值为16和8的梯度组。N∶P值为30的梯度组的浮游植物优势种的时间变化最稳定。  相似文献   

云南石林喀斯特小生境木本植物多样性特征   总被引：2，自引：0，他引：2  

俞筱押  李玉辉  马遵平 《山地学报》2007,25(4):438-447

喀斯特生境与生物多样性的关系及对人为干扰的响应是喀斯特生态恢复的重要内容。以石林世界地质公园为例对此进行研究。从喀斯特溶痕与植物生长发育关系角度看,石林的小生境可分出节理溶沟、裂隙溶沟、楔状槽沟、深溶蚀坑、溶蚀石堆、浅溶蚀盘、溶蚀穿洞、溶蚀井或圆形溶槽和溶蚀廊道等9种。这些小生境的长度在31~340 cm,宽度在10~261 cm。在原生林、次生林、灌丛和灌丛草地等四个群落中调查了各个小生境的木本植物,共记录40科92种,个体数11420株,其中以溶蚀廊道的木本植物总数最多,溶蚀穿洞最少。物种和数量保持最稳定的小生境是溶蚀石堆和裂隙溶沟。各小生境群落间的物种相似性指数很低。裂隙溶沟、深溶蚀坑、楔状槽沟、溶蚀石堆等小生境在人为强烈干扰后,仍保留有部分乡土植物繁殖体,其他小生境缺乏,这些繁殖体对生态严重退化区的喀斯特植被恢复具有重要意义。喀斯特生境的尺度影响森林植被的自然恢复。保护喀斯特地质遗迹可以促进生物多样性恢复和保护,石林世界地质公园提供了例证。  相似文献   

Diversity of Epiphytic Lichens and Hg Contents of Xanthoria parietina Thalli as Monitors of Geothermal Air Pollution in the Mt. Amiata Area (Central Italy)     

Stefano Loppi  Luca Paoli  Carlo Gaggi 《Journal of Atmospheric Chemistry》2006,53(2):93-105

The diversity of epiphytic lichens and mercury concentrations in lichen samples were measured to monitor the release of airborne pollutants from the industrial exploitation of geothermal resources in the Mt. Amiata area (Italy). The lichen biodiversity showed a general condition of moderate environmental alteration around the geothermal power plants, contrasting with the low environmental alteration of the remaining sites investigated. According to the accumulated Hg in lichen thalli, it was possible to estimate mean Hg and H₂S concentrations in the air, which resulted in very good agreement with values measured instrumentally. Based on these data and the correlation between lichen diversity values and Hg concentrations in lichens, it was possible to calculate the threshold of 8 μg/m³ H₂S as responsible for the worsening from low to moderate environmental alteration according to the biodiversity of epiphytic lichens, and to infer that around geothermal power plants, although not toxic to humans, H₂S concentrations are such to alter the nasal quality of the air. Based on the growth rate of X. parietina, it was possible to convert Hg concentrations into estimates of average Hg deposition rates, which showed fluxes of the order of 65–100 mg/ha/y, indicating a dispersions factor of about 10⁴ for the Hg emitted from the geothermal power plants.  相似文献