Mid‐Holocene Development of Mangrove Communities Featuring Rhizophoraceae and Geomorphic Change in the Richmond River Estuary,New South Wales,Australia

This paper describes the hitherto unreported occurrence of mid‐Holocene mangrove deposits in the Richmond River estuary, southeastern Australia, thereby providing evidence for changes in the distribution and composition of mangrove communities within a subtropical estuarine system during the Holocene. Stratigraphic, radiocarbon and palynological evidence indicates that widespread development of mangrove communities took place in the upstream reaches of the Richmond River estuary during the period 7000 to 6000 years BP. These communities maintained their habitat through substrate aggradation under the conditions of a moderate sea‐level rise, in contrast to other estuaries within the region, which generally experienced the submergence of intertidal substrates. Mangrove species belonging to the family Rhizophoraceae, most likely Bruguiera gymnorrhiza and Rhizophora stylosa, dominated these communities, in strong contrast to contemporary communities, which are dominated by Avicennia marina. Moreover, these mid‐Holocene communities were located a considerable distance upstream of the contemporary occurrences of Rhizophoraceae species within the estuary. The changes in the spatial distribution and composition of mangrove communities parallel the large‐scale evolution of the estuary driven by sea‐level variation. Shallow, buried Pleistocene terraces probably contributed to the regionally unique aggradational response of the mangrove communities and their substrates to a sea‐level rise during mid‐Holocene times.     

Historical Perspectives on Pre-Colonial Irrigation in Southern Africa

Abstract

One of the basic areas of interaction between water as natural resource and human societies as agents of cultural transformation is the technology of irrigation. In Africa at least 66 per cent of the available water is used for purposes of irrigation. For more than 4 000 years irrigation has secured food supplies for humans on a continent that is noted for its relative shortage of sufficient natural water supplies.

There is a remarkable hidden power of water in the history of southern Africa. This is particularly the case when we consider the development of early irrigation technologies of Iron Age farmers. The small irrigation furrow of the subsistence farmer was just as important to an insular community of Bantu-speaking people in pre-colonial times, as is the sophisticated irrigation technology in present-day South Africa. Currently there is a paucity of information about pre-colonial indigenous irrigation technology. This can be ascribed to a number of factors of which the invasion of modern Western traditions in the nineteenth century is perhaps the most important. A number of other factors for the apparent blind-spot is also presented in this study.

In southern Africa there are traces of indigenous pre-colonial irrigation works at sites such as Nyanga in Zimbabwe; the Limpopo River Valley; Mpumalanga; and South Africa's eastern Highveld. Reference is also made in this article to specific strategies of irrigation used by Iron Age communities, prior to the advent of a colonial presence. Finally, attention is also drawn to pre-colonial land tenure and state formation against the backdrop of Wittfogel's theories on hydraulic society.     

江苏盐城海滨湿地社区参与生态旅游开发模式研究

社区参与是生态旅游的本质需求,社区参与生态旅游开发对实现盐城海滨湿地生态旅游可持续发展具有重要意义。本文分析了盐城海滨湿地生态旅游开发和社区参与的现状,对湿地社区居民参与旅游开发的态度和行为进行了调查,在此基础上提出了社区居民参与生态旅游的决策规划模式、经营管理模式、产品开发模式以及利益分配模式,并提出了居民参与旅游开发的保障机制。     

洞庭湖湿地景观特征与农业产业化模式研究

洞庭湖湿地是我国最大的淡水湖泊湿地景观生态系统之一,湿地农业资源丰富,农业开发历史悠久,生产化水平较高,是我国重要的农业商品基地。由于过去长期受传统耕作方式的影响,农业产业化程度较低,农业经济发展缓慢;本文根据洞庭湖湿地景观特征,对洞庭湖湿地农业资源和湿地农业开发现状进行了评价和分析,指出了湿地农业开发中存在的问题,提出了洞庭湖湿地农业产业化开发利用模式,以实现洞庭湖湿地农业经济的飞速发展。     

湿地公园建设与湿地旅游资源保护的协调机制研究——以江苏、上海沿海湿地自然保护区为例

本文从湿地公园的概念与研究动态入手,以江苏、上海沿海湿地自然保护区为例,提出了湿地公园建设与湿地旅游资源保护的协调机制,从理念、目标、规划与政策、技术和管理、决策调控五个层面提出协调机制实施的基本模式。通过研究,希望能丰富湿地旅游资源保护的方法和途径,对湿地生态功能结构的维护和资源开发提供新的思路。     

Wetland assessment and impact mitigation decision support framework for linear development projects: The Louis Riel Trail,Highway 11 North project,Saskatchewan, Canada

Next to agriculture, road development is one of the most significant sources of stress to wetlands in Prairie Canada. However, there currently exists limited guidance for incorporating direct, indirect, and induced effects to wetlands in impact assessment and mitigation planning for small and often routine developments, including access roads or highway improvement initiatives. Based on the Louis Riel Trail, Highway 11 North twinning project in Saskatchewan, Canada, this article demonstrates a methodological approach and decision support framework for assessing and managing direct, indirect, and induced effects to wetlands from linear developments. No regulatory‐based environmental assessment was required for the highway project; effects were deemed to be insignificant under current wetland mitigation practices. However, our results show that 1115 ha of potentially affected wetlands are located within a 500 m impact zone on either side of the proposed highway. More than 50 percent of these wetlands are seasonal, less than 1 ha in size, and typically not included in mitigation planning. An expert‐based multi‐criteria evaluation of impact and mitigation options for wetlands in the study area indicated “no net loss” as a planning priority, and a preference for a spatially ambitious mitigation plan focused on direct, indirect, and potentially induced impacts. In practice, however, mitigation is often restrictive, focused on mitigating only direct impacts within the project's right‐of‐way, in this case less than 50 ha of wetlands, resulting in the potential for significant net loss of wetland habitat and function. If the risk to wetlands is to be given due consideration in project planning and development for roads and road improvement initiatives, then structured assessment methods and decision support frameworks should be sensitive to the time and resource constraints of small projects and screening‐type assessments. This requires also that wetland mitigation policies are developed and implementation plans formulated as part of project planning and assessment initiatives for linear developments.     

湿地公园游步道设计的探讨——以杭州西溪国家湿地公园为例

随着湿地公园旅游热的兴起,更为生态化的公园设计显得尤为重要,而游步道作为游客游览的主要通道,正越来越受到关注。本文以杭州西溪国家湿地公园为例,阐述了游步道设计在湿地公园保护中的重要地位和作用,提炼出湿地公园游步道设计的遵循原则,并针对设计中的各个要素进行详细地分析和研究,提出湿地公园游步道的设计应充分体现旅游行为与生态保护的融合。     

洞庭湖区湿地生态旅游资源开发模式研究

洞庭湖区湿地是我国最大的淡水湖泊湿地生态系统之一,湿地资源特别丰富,开展湿地生态旅游资源条件十分优越;本文根据洞庭湖区湿地呈同心环带状分布的特征,对洞庭湖区湿地资源进行了景观分类:即洞庭湖湖泊河汊区、洞庭湖湿地平原区、洞庭湖环湖低丘岗地区;分析了洞庭湖区湿地旅游资源的特征和开发利用现状,按照洞庭湖湿地各环带生态旅游资源的特点,提出了洞庭湖湿地生态旅游资源开发模式:即洞庭湖湖泊河汊区生态旅游资源开发模式,洞庭湖湿地平原区生态旅游资源开发模式,洞庭湖环湖低丘岗地区生态旅游资源开发模式;并就湿地生态旅游资源开发中应注意的问题作了说明,以期达到保护湿地生态环境,合理开发湿地生态旅游资源,实现洞庭湖区湿地旅游资源可持续发展的目的。     

Tools for Predicting Damage to Archaeological Sites Caused by One-Dimensional Loading

Tools are developed to predict damage to archaeological remains caused by the construction of line infrastructure on soft soil. They are based on numerical modelling and laboratory testing supported by X-ray microcomputed tomographic observations, and micromorphological analyses of thin sections. They have been validated for one-dimensional (1D) loading at two sites in the Netherlands where soil has been placed on top of organic layers rich in ecofacts and overlaying Pleistocene sands.

Numerical prediction of the deformation of soft layers underneath an embankment remains a challenge for geo-technical engineers. Errors on surface settlement prediction reach ±15% of the measured total settlement.

Laboratory observations show that vulnerable artefacts can get crushed when packed loosely in pure assemblies under 1D loading equivalent to less than 5 m of sand. Fragmentation is assimilated to loss of archaeological value as it compromises recovery during sieving. Embedment in a sandy or a very compressible organic matrix has a beneficial effect on the resistance of ecofacts. Embedded ecofacts can resist a load of more than 12 m of sand. Flattening and re-orientation of soft plant remains occur during 1D loading without microscopic damage of tissues.     

黑河中游湿地社区管理评价的居民感知研究——以甘肃省酒泉市六分湿地为例

以黑河中游酒泉市六分湿地社区管理为例,从居民感知视角,采用因子分析、非参数检验等方法评价了湿地社区管理绩效。结果表明:整体居民感知均值为3.71,社区管理模式符合当地社会经济及环境的发展需求;不同性别的居民感知差异不显著(P>0.05),与男女性格差异吻合;各年龄段的居民感知存在差异(P<0.05),感知规律曲线大致呈倒"U"形;不同文化程度的居民感知差异显著(P<0.05);不同收入的居民感知差异却不显著(P>0.05)。不同利益群体对社区管理的关注视角不同,居民感知存在差异。资源管理居民感知研究,尊重利益相关者的价值判断,注重地域性文化及居民综合需求的影响,实现了资源管理的集成定量评价。