Grassland habitat mapping by intra-annual time series analysis – Comparison of RapidEye and TerraSAR-X satellite data

Remote sensing concepts are needed to monitor open landscape habitats for environmental change and biodiversity loss. However, existing operational approaches are limited to the monitoring of European dry heaths only. They need to be extended to further habitats. Thus far, reported studies lack the exploitation of intra-annual time series of high spatial resolution data to take advantage of the vegetations’ phenological differences. In this study, we investigated the usefulness of such data to classify grassland habitats in a nature reserve area in northeastern Germany. Intra-annual time series of 21 observations were used, acquired by a multi-spectral (RapidEye) and a synthetic aperture radar (TerraSAR-X) satellite system, to differentiate seven grassland classes using a Support Vector Machine classifier. The classification accuracy was evaluated and compared with respect to the sensor type – multi-spectral or radar – and the number of acquisitions needed. Our results showed that very dense time series allowed for very high accuracy classifications (>90%) of small scale vegetation types. The classification for TerraSAR-X obtained similar accuracy as compared to RapidEye although distinctly more acquisitions were needed. This study introduces a new approach to enable the monitoring of small-scale grassland habitats and gives an estimate of the amount of data required for operational surveys.     

洞庭湖区"冬陆夏水"区域变化研究

利用遥感与地理信息系统技术,提取1987,1998,2003和2008年4个时段洞庭湖"冬陆夏水"区域.运用改进归一化差异水体指数(MNDWI)的方法,提取丰水期和枯水期遥感图像的水体并相减,获得"冬陆夏水"区域,并对20年的"冬陆夏水"变化的面积进行监督分类.分析发现,研究区的"冬陆夏水"面积,从1987年到2008...     

Adaptive management,international co-operation and planning for marine conservation hotspots in a changing climate

The aim of this study is to predict changes in the distribution and extent of habitat forming species defined as “Priority Marine Habitats” (PMHs) in the North-East (NE) Atlantic under future scenarios of climate-induced environmental change. A Species Distribution Modelling method was used for each PMH to map the potential distribution of “most suitable” habitat. The area and percentage cover was calculated within each country׳s Exclusive Economic Zone for the baseline (2009) and the projected (2100) years. In addition, a conservation management score was calculated based on the number of PMHs that co-occur in assessment units. Overall, this study reveals the potential for movement and/or change in the extent of some PMHs across the NE Atlantic under an increased ocean temperature scenario (4 °C) by 2100. There are regional differences in the predicted changes and some countries will experience greater/different changes than others. The movement of biodiversity hotspots (where one or more PMHs occur in the same broad area) provides both opportunities and risks for conservation management that are discussed. Co-operation between neighbouring countries and marine regions will require substantial enhancement in order to provide a robust adaptive management strategy going forward.     

The possibility analysis of habitats, origin and reappearance of bloom green alga （Enteromorpha prolifera） on inshore of western Yellow Sea

Combining some information from field investigation of algae along the coastal areas in China and a few pictures materialized from the western Yellow Sea in 2008,authors analyze the necessary conditions and possible water area in China producing a large biomass,some reasons for firestorm,and the possibility of the reappearance of marine bloom green alga Enteromorpha prolifera.The change of habitats and the increase of nutritional levels related to the water area could be considered as direct reasons.It was ...     

A preliminary study of habitat and resource partitioning among co-occurring tropical dolphins around Mayotte, southwest Indian Ocean

Mayotte in the southwest Indian Ocean is characterized by high dolphin diversity. They may coexist within a fairly small area around the island because they exploit neither the same preferential habitats nor the same resources. This preliminary study aimed to investigate ecological niche segregation among these delphinid communities: the Indo-Pacific bottlenose dolphin, Tursiops aduncus, the pantropical spotted dolphin, Stenella attenuata, the spinner dolphin, Stenella longirostris, and the melon-headed whale, Peponocephala electra. Two approaches were used. Habitat preferences were investigated by analysing dolphin sighting data and associated physiographical characteristics. Resource partitioning was explored by analysing C and N stable isotopes in skin and blubber biopsies. Only T. aduncus, which showed clear association with coastal habitats in the lagoon, differed from the others in terms of habitat preferences, characterised by shallow depth and slope, and proximity to the coast. All other species shared similar oceanic habitats immediately outside the lagoon, these being of higher depth and slope, greater distance from the coast and were not discernable by discriminant analysis. The two Stenella species and the melon-headed whale displayed very high overlap in habitat physiographic variables. The analysis of stable isotopes confirmed the ecological isolation of T. aduncus and revealed a clear segregation of P. electra compared to the two Stenella that was not apparent in the habitat analysis. This may reflect ecological differences that were not observable from diurnal surface observations.     

The Socio-Economic Costs and Benefits of Coastal Habitat Rehabilitation and Creation

This paper provides a comprehensive overview of the merits and limitations of using an economics based approach to assess and implement initiatives for coastal habitat rehabilitation and creation. A review of the literature indicates that habitat rehabilitation/creation costs vary widely between and within ecosystems. For coral reefs, costs range from US$ 10,000 to 6.5 million/hectare (ha);¹ for mangroves US$ 3000–510,000/ha; for seagrasses US$ 9000–680,000/ha and for saltmarshes US$ 2000–160,000/ha. A review of the economic benefits derived from various coastal habitats based on a ‘Total Economic Value’ approach (i.e. accounting for direct and indirect uses, and ‘non-uses’) reveals that many thousands of US$ per hectare could ultimately accrue from their rehabilitation/creation. The paper concludes that despite its limitations, the ‘benefit-cost analysis’ framework can play an important role both in assessing the justification of coastal habitat rehabilitation/creation initiatives, and by helping to improve the overall effectiveness of such initiatives.     

荒漠绿洲边缘凝结水量及其影响因子

以2004年7~10月在临泽内陆河流域综合研究站凝结水试验观测数据为基础,讨论了荒漠绿洲边缘凝结水凝结过程、不同下垫面凝结量及其影响因子.结果表明:荒漠绿洲边缘凝结水以吸湿凝结为主,北京时间16:00~18:00开始,至次日7:00~8:00结束.凝结开始的时间受控于沙地含水量,凝结量则主要受近地表相对湿度、近地表气温以及气温日较差三方面因素的影响.人工草地、平坦无植被沙地、沙丘顶部、丘间低地和人工林地在7~10月的平均月凝结量分别为:5.1 mm、4.0 mm、3.1mm、1.8 mm和1.0 mm.     

干旱、半干旱区几种典型生境蛴螬群落特征比较研究

1998- 1999年,对我国北方干旱、半干旱区几种典型生境(腾格里沙漠生态系统、内蒙古典型草原、科尔沁沙地)的蛴螬群落作了比较研究,结果表明:东方绢金龟(Serica orientalis Motschulsky)在3个采样区的优势度均为最高,3个采样区蛴螬群落的次优势种相互间有差别,内蒙古典型草原多为黑皱鳃金龟(Trematodes tenebrioides(Pallas))和弓斑常丽金龟(Cyriopertha arcuata(Gebler)),科尔沁沙地为黄褐异丽金龟(Anomala exoleta Faldermann)和灰胸突鳃金龟(Hoplosternus incanus Otschulsky),腾格里沙漠生态系统为黄褐异丽金龟(Anomala exoleta Faldermann)。腾格里沙漠生态系统蛴螬群落组成单调、密度极低是不言而喻的,科尔沁沙地蛴螬群落密度不如内蒙古典型草原高,多样性指数是最高的。就3个样区蛴螬群落的相似性而言,科尔沁沙地与内蒙古典型草原的相似性要低于与腾格里沙漠生态系统的相似性。     

Fish persistence and fluvial geomorphology in central Australia

The purposes of this paper are to document the composition and distribution of fishes in the Alice Springs region of Australia, and discuss constraints on fish persistence in this arid region. Nine native and six exotic species were recorded; most exotics no longer exist. Except in Finke River, only one or no native species were found. Fish survival in the area is ameliorated by the exceptionally broad environmental tolerances and migratory abilities of many species, but ultimately depends upon the effects of geology, geomorphology, and the vagaries in pattern of sediment transport on water persistence.