A global assessment of the vulnerability of shellfish aquaculture to climate change and ocean acidification

Human‐induced climate change and ocean acidification (CC‐OA) is changing the physical and biological processes occurring within the marine environment, with poorly understood implications for marine life. Within the aquaculture sector, molluskan culture is a relatively benign method of producing a high‐quality, healthy, and sustainable protein source for the expanding human population. We modeled the vulnerability of global bivalve mariculture to impacts of CC‐OA over the period 2020–2100, under RCP8.5. Vulnerability, assessed at the national level, was dependent on CC‐OA‐related exposure, taxon‐specific sensitivity and adaptive capacity in the sector. Exposure risk increased over time from 2020 to 2100, with ten nations predicted to experience very high exposure to CC‐OA in at least one decade during the period 2020–2100. Predicted high sensitivity in developing countries resulted, primarily, from the cultivation of species that have a narrow habitat tolerance, while in some European nations (France, Ireland, Italy, Portugal, and Spain) high sensitivity was attributable to the relatively high economic value of the shellfish production sector. Predicted adaptive capacity was low in developing countries primarily due to governance issues, while in some developed countries (Denmark, Germany, Iceland, Netherlands, Sweden, and the United Kingdom) it was linked to limited species diversity in the sector. Developing and least developed nations (n = 15) were predicted to have the highest overall vulnerability. Across all nations, 2060 was identified as a tipping point where predicted CC‐OA will be associated with the greatest challenge to shellfish production. However, rapid declines in mollusk production are predicted to occur in the next decade for some nations, notably North Korea. Shellfish culture offers human society a low‐impact source of sustainable protein. This research highlights, on a global scale, the likely extent and nature of the CC‐OA‐related threat to shellfish culture and this sector enabling early‐stage adaption and mitigation.     

Assessing the Effects of Invasive Alien Species on Rural Livelihoods: Case Examples and a Framework from South Africa

The detrimental impacts of invasive alien species (IAS) on ecosystem goods and services and local and regional economies are well documented. However, the use of IAS by rural communities is little understood, and rarely factored into IAS control programmes. Understanding the use of IAS by rural communities and factoring these into cost-benefit models is complex, depending upon a range of local-level attributes such as the time since invasion, abundance, and local-level costs and benefits. This paper reports on two case studies examining the role of IAS in rural livelihoods in the Eastern Cape, South Africa. In both cases, rural communities made widespread consumptive use of the IAS and generally would prefer higher densities, except in certain key localities. Several households traded in IAS products to generate supplementary income. We present a conceptual framework to guide interpretation of these and future case studies, considering attributes such as time since invasion, the competitiveness of the species, and the relative costs and benefits.     

The traditional broom trade in Bushbuckridge, South Africa: Helping poor women cope with adversity

The extensive local and regional market for traditional, handcrafted twig and grass brooms in the Bushbuckridge municipality, South Africa, provides an important means of livelihood security for several hundred poor households in the face of increasing economic hardship. Participants in this trade were a vulnerable group of middle-aged to elderly women with poor levels of education and few assets. Over half headed their own house-holds, and several came from households affected by AIDS. Entry into the broom trade was mainly a coping strategy in response to crisis, becoming long-term in the absence of alternatives. Average net annual incomes for producers and traders were modest at ZAR 2,000 and ZAR 1,000 respectively (ZAR=South African Rand), although some were earning considerably more. While unlikely to provide a way out of poverty, the trade was critical in allowing diversification and in providing a safety net, assisting poor households to overcome adversity, meet several basic needs, and educate their children.     

Analysis of the ecological vulnerability of the western Hainan Island based on its landscape pattern and ecosystem sensitivity

The ecological vulnerability of the western Hainan Island of China was assessed using a combined approach of landscape pattern and ecosystem sensitivity. Models were developed using the following five factors: reciprocal of fractal dimension (FD), isolation (FI), fragmentation (FN), sensitivity of land desertification (SD), and sensitivity of soil erosion (SW). The major findings include: (1) the vulnerability of various landscape types was in the following decreasing order: farmland > forestland > water area. This suggests that the ecosystems of farmland and forestland are unstable and sensitive to external disturbances; (2) significantly positive relationships were found between the vulnerability of landscape types (VI) and SD, VI and FN, FN and SD, and FN and EVI (regional eco-environment vulnerability). This suggests that FN and SD have considerable effects on VI and EVI in this case; (3) there is a good agreement between the predicted and the actual distribution of the EVI zones. EVI value tends to decrease with increasing distance from the coastline and increase with increasing altitude; (4) the landscape pattern and the regional ecological vulnerability in this study is predominantly controlled by human activities, although physical factors such as topography and oceanic influences also play roles in the process; and (5) the establishment of relationships between data with respect to landscape and the regional ecological responses could be beneficial in guiding the ecological construction of this region.     

Integrated assessment and changes of ecological environment in the Daning River Watershed

Based on Remote Sensing (RS), Geographical Information Systems (GIS), and the Spatial Principal Component Analysis (SPCA) method, the integrated assessment and changes in the ecological environment of Daning River Watershed are studied in this paper. The watershed is located in the Three Gorge Area in China. The result of the integrated assessment showed that level 9 had the biggest proportion in the year 1990, which was about 40%. In the year 2000, however, there were no levels with a proportion significantly bigger than the others. By comparing the assessment results in 1990 and 2000, it is discovered that the ecological environment in Daning River Watershed in 1990 was better than that in 2000. __________ Translated from Journal of Beijing Normal University (Natural Science), 2006, 42(2): 200–203 [译自: 北京师范大学学报 (自然科学版)]     

基于遥感影像的城市土地利用生态环境效应研究——以城市热环境和植被指数为例

城市化过程中,农村的土壤、水面以及植被等土地覆被类型逐渐减少,取而代之的是由沥青、水泥以及金属等组成的不透水表面,这个过程导致地表水分蒸腾减少、径流加速、显热的存储和传输增加以及水质降低等一系列生态环境效应,其中最明显的两个特征就是土地覆被的植被减少、城市热岛的出现.而城市土地利用类型及其空间结构的生态环境效应同时又是城市生态学中的关键问题,其研究对优化城市功能分区和城市规划管理以及城市可持续发展等都具有重要意义.以上海市为例,采用Landsat7的ETM＋为基本数据源,首先定量反演了每个像元内的陆地表面温度（LST）和植被指数（NDVI）,然后利用GIS中的空间分析功能,将由于城市土地覆被所形成的生态环境效应综合到土地利用的图斑中来,按照这个思路对城市土地利用的生态环境效应进行研究.分析LST、NDVI在不同土地利用类型之间的差异以及二者之间的定量关系,并引入多样性指数（SHDI）,讨论了不同土地利用的空间组合下,LST和NDVI的空间差异及相互关系.研究结果显示：LST和NDVI具有明显的相关性,LST大的区域对应NDVI一般都较小,反之亦然;中心城市LST表现出热岛效应,而NDVI则为低谷效应.通过Tamhance T2 post-hoc多重比较发现,LST以及NDVI在两两土地利用类型之间的差异不同.从土地利用斑块和类型两种尺度水平上建立了LST和NDVI的定量关系,二者具有明显负相关的线性关系,但在不同土地利用类型上二者关系并不同.其中工业仓储、交通用地与公园绿地、农业用地差异最为显著.它们和SHDI之间的关系揭示,LST与土地利用多样性具有正相关关系,而NDVI则与SHDI呈负相关关系,SHDI越大的地区,LST越大,而NDVI越小.由此,可以将LST、NDVI和SHDI作为三个基本指标,来定量评价城市土地利用类型、结构对生态环境的影响,以此作为城市功能分区中生态环境影响评价的参考.也为高性价比的中等分辨率遥感数据与GIS空间分析方法结合在城市规划中的应用提供了一种新的思路.     

Hydraulic properties and freezing-induced cavitation in sympatric evergreen and deciduous oaks with contrasting habitats

We investigated the hydraulic properties in relation to soil moisture, leaf habit, and phylogenetic lineage of 17 species of oaks (Quercus) that occur sympatrically in northern central Florida (USA). Leaf area per shoot increased and Huber values (ratio of sapwood area to leaf area) decreased with increasing soil moisture of species’ habitats. As a result, maximum hydraulic conductance and maximum transpiration were positively correlated with mean soil moisture when calculated on a sapwood area basis, but not when calculated on a leaf area basis. This reveals the important role that changes in allometry among closely related species can play in co‐ordinating water transport capacity with soil water availability. There were significant differences in specific conductivity between species, but these differences were not explained by leaf habit or by evolutionary lineage. However, white oaks had significantly smaller average vessel diameters than red oaks or live oaks. Due to their lower Huber values, maximum leaf specific conductivity (K_L) was higher in evergreen species than in deciduous species and higher in live oaks than in red oaks or white oaks. There were large differences between species and between evolutionary lineages in freeze–thaw‐induced embolism. Deciduous species, on average, showed greater vulnerability to freezing than evergreen species. This result is strongly influenced by evolutionary lineage. Specifically, white oaks, which are all deciduous, had significantly higher vulnerability to freezing than live oaks (all evergreen) and red oaks, which include both evergreen and deciduous species. These results highlight the importance of taking evolutionary lineage into account in comparative physiological studies.     

Intraspecific variation in tolerance of warming in fishes

Intraspecific variation in key traits such as tolerance of warming can have profound effects on ecological and evolutionary processes, notably responses to climate change. The empirical evidence for three primary elements of intraspecific variation in tolerance of warming in fishes is reviewed. The first is purely mechanistic that tolerance varies across life stages and as fishes become mature. The limited evidence indicates strongly that this is the case, possibly because of universal physiological principles. The second is intraspecific variation that is because of phenotypic plasticity, also a mechanistic phenomenon that buffers individuals’ sensitivity to negative impacts of global warming in their lifetime, or to some extent through epigenetic effects over successive generations. Although the evidence for plasticity in tolerance to warming is extensive, more work is required to understand underlying mechanisms and to reveal whether there are general patterns. The third element is intraspecific variation based on heritable genetic differences in tolerance, which underlies local adaptation and may define long-term adaptability of a species in the face of ongoing global change. There is clear evidence of local adaptation and some evidence of heritability of tolerance to warming, but the knowledge base is limited with detailed information for only a few model or emblematic species. There is also strong evidence of structured variation in tolerance of warming within species, which may have ecological and evolutionary significance irrespective of whether it reflects plasticity or adaptation. Although the overwhelming consensus is that having broader intraspecific variation in tolerance should reduce species vulnerability to impacts of global warming, there are no sufficient data on fishes to provide insights into particular mechanisms by which this may occur.     

湖泊生态环境损害基线判定技术综述

近年来,污染事故引发的湖泊生态环境损害问题屡见不鲜,特别是氮磷营养盐富集导致的湖泊富营养化。因此,对湖泊生态环境损害程度进行科学合理评判,制定湖泊生态环境损害判定规范程序,形成湖泊生态环境损害判定技术势在必行。目前,国内外学者一致认为,确定切实合理的生态环境基线是对生态环境损害进行科学有效评估的关键技术环节和重要前提。基于相关国家标准以及文献调研,对湖泊生态环境基线判定的原则、判定程序以及判定方法进行系统梳理与总结。详细介绍了针对湖泊不同受体的模型推算法在生态环境损害基线判定中的应用,包括相应的判定方法、判定过程以及优缺点。此外,还针对国内外典型湖泊生态环境损害基线判定研究实例进行阐述。最后对湖泊生态环境基线判定工作的未来发展方向进行了展望,以期为形成统一、合理、有效且具有高度普适性的湖泊生态环境基线制定方法与流程提供依据。