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1.
Mangrove forests provide vital ecosystem services for millions of people living in coastal communities. The expansion of aquaculture production and urbanization have been identified as major causes of mangrove clearance in South-East Asia. The Ca Mau peninsula in Vietnam is leading the country in shrimp aquaculture and at the same time, the region is home to the largest remaining mangrove forests. This study aims to assess the spatial and temporal mangrove forest dynamics in Ngoc Hien district in Ca Mau. Land cover change and fragmentation are quantified using remote sensing imagery consisting of a series of SPOT5 scenes from 2004, 2009 and 2013. The results indicate a high turnover of land cover change, with close to half of the mangrove forests being affected by land cover changes between 2004 and 2014. Net changes in mangrove forest are found to average −0.34% annually, characterized by deforestation between 2004 and 2009 and afforestation of between 2009 and 2013. Fragmentation remains a plausible threat; approximately 35.4% of the mangrove forests in Ngoc Hien are part of interior ‘core’ forests. Forest zones with different regulation regimes play a significant role in shaping the geographic distribution of mangrove forest changes. The insights into recent mangrove forest dynamics facilitate the informed discussion on improving future protection of the mangrove forests abiding anthropogenic pressures. 相似文献
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Thi Thuy Hanh Nguyen 《Singapore journal of tropical geography》2019,40(3):452-475
This study identified spatial patterns of forest change in Hoa Binh, Vietnam, from 2005 to 2017 by integrating Landsat data and Geographic Information System (GIS) data. A Multiple Logistic Regression (MLR) model was adapted to analyse drivers of three types of forest change, including (i) deforestation and forest degradation, (ii) forest regrowth and (iii) plantation expansion. The results reveal that accessibility and local economic development were determinants of forest cover dynamics during the integration and globalization period and that increased population pressure and poverty were no longer the main factors in forest cover transition. Several key policies in this time period positively affected forest cover change, triggering private sector participation in developing the forest economy by including households and small and medium enterprises in particular. The findings of this study can provide learning points for the implementation of sustainable forest management policies in other Vietnamese provinces or in neighbouring countries. This research has provided an effective tool for visualizing human‐forest ecosystem interaction, and this tool can be applied to subsequent studies to determine causes of forest cover change at the provincial level in Vietnam. 相似文献
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Ian G. Baird William Noseworthy Nghiem Phuong Tuyen Le Thu Ha Jefferson Fox 《Singapore journal of tropical geography》2019,40(1):50-70
Since the early 2000s the Lao government has dramatically increased the number of large‐scale land concessions issued for agribusinesses. While studies have documented the social and environmental impacts of land dispossession, the role of Vietnamese labour on these Vietnamese‐owned rubber plantations has not previously been investigated. Taking a political ecology approach, we situate this study at the intersection between ‘land grabbing’ studies and work on ‘labour geographies’. Most of the remittances generated from Vietnamese working in Laos are used for non‐agricultural purposes, with people purposely choosing to not invest in agriculture in Vietnam. Vietnamese labour on Lao plantations still has significant spatial implications, both in Laos and in Vietnam, including through the norms, formal rules and practices introduced at rubber plantations by Vietnamese workers and management, but also through labour regime changes in Vietnam. In Laos, one of the most significant results has been to make certain spaces less welcoming to Lao labour. This study particularly points to the importance of geopolitics, as the close political relationship between Laos and Vietnam, and the fact that Vietnamese companies and managers are involved, is crucial for understanding the particular nature of the labour geographies associated with Vietnamese rubber plantations in Laos. 相似文献
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AbstractEnvironmental challenges in the Vietnamese Mekong Delta characterized by adverse impacts of climate change, upstream hydropower development and localized dyke expansion present imperatives for rural farmers to “learn to adapt.” However, little is known about how learning contributes to improving their capacity in adapting to these “wicked” problems. This study investigates potential effects of farmers’ learning on their adaptive capacity, utilizing nine focus group discussions, 33 interviews, and a structured survey of 300 farmers. The exploratory factor analysis produced two factors for social learning: (1) learning through social interactions and (2) self-reflection, and one factor for adaptive capacity. The regression results show that the social learning factors have significantly positive effects on adaptive capacity. Farmers with a higher level of social learning are likely to demonstrate higher adaptive capacity. The findings call for policy considerations to promote learning in a broader context of the delta to enhance local capacity. 相似文献
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生态城市建设背景下湛江红树林的保护与利用 总被引：3，自引：1，他引：2
以中国最大的红树林生长基地———湛江市为例,经过实地调研和多方论证,分析了当前湛江红树林的生存现状和存在的问题。究其原因在于:对红树林在区域生态安全格局中的战略意义认识不足、当地社会经济发展带来的巨大冲击,以及红树林资源开发的滞后等。针对这些问题,首先从海陆一体化、海岸带等方面,明确了红树林湿地在维护区域生态安全格局中的战略地位。在此基础上,厘清了红树林湿地在湛江生态城市建设中的意义和作用,提出了今后湛江红树林湿地的总体建设方向:(1)以红树林湿地为核心,重构湛江市的区域生态安全格局;(2)加强湛江市红树林生态系统的重构;(3)开展沿海红树林的生态恢复;(4)推进生态旅游产业的开发。 相似文献
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Mangroves are woody plant communities in the intertidal zone of tropical and subtropical coasts that play an important role in these zones. The infrared wave band is one of the key bands in the remote sensing identification of mangrove forest, and ALI (advanced land imagery) has a large number of infrared bands. Two angle indices were proposed based on liquid water absorption at band 5p and band 5 of EO-1 ALI, denoted as β1.25 and β1.65 respectively. A decision tree method was adopted to identify mangrove forest using remote sensing techniques for β1.25-β1.65 and NDVI (normalized difference vegetation index) for EO-1 ALI imagery acquired at Shenzhen Bay. The results showed that the reflectance of mangrove forests at band 5p and band 5 was significantly lower than that of terrestrial vegetation due to the characteristics of coastal wetlands of mangrove forests. This resulted in a greater β1.25-β1.65 value for mangrove forest than terrestrial vegetation. The decision tree method using β1.25-β1.65 and NDVI effectively identifies mangrove forest from other land cover categories. The misclassification and leakage rates were 4.29% and 5.11% respectively. ALI sensors with many infrared bands could play an important role in discriminating mangrove forest. 相似文献
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以广东沿海红树林为研究对象,结合谷歌地球引擎（GEE）云计算平台,以1986—2018年32期3 359景Landsat系列卫星遥感影像为数据源,采用随机森林（RF）方法提取1986—2018年广东省红树林面积,比较全省沿海城市红树林年际时空变化特征,并从景观斑块角度分析广东省红树林斑块演变特征。结果表明：1）1986—2018年红树林遥感分类总体精度均高于90%,广东省沿岸红树林面积总体呈先减少后增加的趋势,且其在2014年后变化幅度逐渐减小。2）从各沿海城市来看,红树林共分布在14个市内,其中湛江和阳江是红树林面积分布最大的2个城市;各市红树林面积变化可分为先减后增、波动增加和无明显变化3类。3）1986—2018年广东省红树林斑块数量总体呈减少趋势,但斑块平均面积（MPS）呈上升趋势,红树林破碎化程度减轻。获取年际红树林面积分布信息和空间结构变化趋势,可为红树林合理开发与保护提供数据和参考,服务于红树林生态恢复和精细化管理。 相似文献
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深圳红树林湿地的现状及生态旅游开发对策 总被引：8，自引：1，他引：8
红树林是生长在热带和亚热带沿海潮间带的木本植物群落,有其独特的生态系统。它具有极其重要的生态、社会和经济效益,同时也是一种新兴的生态旅游资源。介绍了深圳红树林湿地的现状、面临的主要威胁,并结合实际情况对开发红树林生态旅游提出了建议。 相似文献
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红树林是一种高效率的滨海蓝碳生态系统,准确估算红树林地上生物量对研究碳循环和气候变化十分重要,获取中国红树林地上生物量将具有现实意义和应用价值。遥感技术便捷高效、观测范围广,能够服务于大尺度的生态系统监测。文章使用基于GEDI星载激光雷达反演的森林冠层高度数据和基于异速生长原理构建的红树林“树高-生物量”异速生长方程,估算2019年中国红树林地上生物量,进而分析其数量、空间分布特征及主要影响因素。结果显示,2019年中国红树林地上生物量总量和均值分别约为1 974 827 t和73.0 t/hm2;红树林分布的各省份(地区)的地上生物量均值在53.3～92.1 t/hm2,其中海南省的红树林地上生物量均值最高,达到92.1 t/hm2;中国红树林地上生物量的累积和分布受纬度和人为因素的影响。研究结果能够为后续红树林生态系统碳储量的核算提供数据基础和技术参考,也将有助于中国沿海红树林生态恢复和保护措施的制定,以及控制碳排政策的出台实施。 相似文献
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Noparat Bamroongrugsa Chorthip Purintavarakul 《湿地科学》2006,4(2):91-95
1 INTRODUCTIONThe rapid increase in the production of culturalmarine shrimp in many countries has caused largescale conversion of mangrove to shrimp ponds.Manyof these endeavors have proven non-sustainable,largely due to inappropriate construction methods… 相似文献
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Leigh Miller 《The Australian geographer》1995,26(2):104-111
The core questions pertaining to contract farming or ‘vertical co‐ordination’ relate to the ownership of decision‐making. Where decision‐making is partly removed from farmers there arise issues of sustainability which are inadequately addressed by current practice. A mail questionnaire conducted in North‐west Tasmania in 1990–91 obtained responses from 310 farmers, a 68 per cent return rate from the 456 valid cases initially identified. At the time of the survey, 119 respondents were involved in contract cropping, and a majority of these responses indicated a need for greater co‐ordination in farm planning. This co‐ordination requires a re‐think of the roles of both agribusiness firms and farmer organisations, as well as acceptance by farmers that long‐term planning for crop rotation and soil management has associated self‐benefit. Responsibility for soil erosion is seen to lie partly at the feet of processing firms which relegate production tasks to farmers under contract, but frequently appear to ignore the impact of short‐term planning horizons upon farmer capacity to manage soils for erosion minimisation. With few exceptions, such as the processor firm specialising in the perennial crop pyrethrum and one onion processor that encourages soil conservation, in North‐west Tasmania processing firms generally play no part in planning for sustainable land use. 相似文献
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福建宁德市红树林资源现状与保护 总被引：1，自引：0，他引：1
2005年8-10月,我们对宁德市滨海湿地及红树林资源进行了全面系统的调查。调查表明:宁德市滨海湿地及红树林资源较为丰富,现有秋茄林面积为93.2hm2,是福建省红树林资源的重要分布区;但同时亦存在红树林面积逐年下降,天然林比重下降、人工林比重上升,林分质量,郁闭度等级、树高等级、集约度、树龄等都有所下降的现象,红树林仅为上世纪70年代末的13%左右。为此,制定湿地及红树林保护法规,拟订和实施红树林保护恢复与发展规划,提高造林和管护成效,实施抢救性保护已是当务之急。 相似文献
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为揭示东南亚红树林的时空变化特征及其变化驱动因素,基于Google Earth Engine (GEE)云计算平台,利用Landsat系列卫星数据及红树林分布数据集,采用趋势分析法分析了1990—2020年东南亚红树林的时空变化趋势,并利用地理探测器分析其时空变化的驱动因子。结果表明：1) 1990—2020年东南亚红树林面积整体呈下降趋势,面积减少1 467 883.1 hm2,年平均流失速率达1.1%;2)红树林面积增加的区域主要分布在菲律宾、印度尼西亚西部和东部以及越南北部等区域;3) 1990—2020年东南亚红树林退化的区域远远多于改善的区域,退化的区域占红树林总分布面积的79.25%,改善的区域占20.32%,仅0.43%的区域稳定不变;4)红树林变化受驱动因素的影响程度排序主要为养殖池面积>人口>红树林距道路的最短距离>年均温>年均降雨>地形,且各因子之间呈现交互增强作用,增强效果较为明显的主要有：养殖池面积-人口、养殖池面积-红树林距道路最短距离、人口-红树林距道路最短距离。 相似文献
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越南是中国重要的海陆邻国,开展其人口分布的研究对揭示越南人口发展规律和服务“一带一路”建设具有重要意义。基于越南2000—2019年人口统计数据,采用GIS空间分析方法揭示了越南21世纪以来人口时空分布特征,并依据人口密度和人口增长速度进一步划分其人口演变类型,最后从地形起伏度,人均GDP和外商投资总额3个因素分析了越南人口时空分异的影响机制。结果表明：①越南人口总量即将突破1亿大关,但人口增长率不断下降,近年来逐渐稳定在1.10%左右。②“南北多中间少,东部沿海多,西部内陆少”是越南人口空间分布总体特征,这与其国土形状与地形特征紧密吻合。近20年越南人口高密度地区基本稳定,全国人口空间分布格局变化较小。③越南人口分布演变类型以中高密度慢速增长为主（61.91%）,而人口快速增长地区可以分为社会经济发达地区的中高密度快速增长与西北部边境和西原地区的低密度快速增长两种类型。④以地形起伏度为代表的自然地理要素决定了越南人口分布的基本格局,以人均GDP和外商投资总额为代表的经济发展水平是人口集疏过程的根本动力,但越南边境地区的人口快速增长则明显受到政府宽松的生育政策和对主体民族京族移民实边政策的影响。 相似文献
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Women in the US have farmed for centuries, but have infrequently had the farmer title. Rural sociologists have explored women’s on-farm roles, as well as rural conceptualizations of gender that influence who can be a farmer. As the proportion of women claiming the farmer title increases, it is important to explore women farmers’ experiences. This article focuses on sixteen farmers in Colorado across the conventional-alternative spectrum. Through engagement with feminist and rural sociological theory, and based on analysis of semi-structured interviews, we contend that women in this study expand what it means to be a farmer by performing femininity through carework within their farming practice. This study demonstrates how some women farmers adapt a variety of predominantly feminine-coded work—such as education, customer support, and feeding work—to make agriculture a space of carework, and farming a role expanded beyond a masculine ideal. 相似文献
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We report a study of the Holocene coastal sediments of the Hai Phong area of the Bac Bo Plain (also known as the Red River Delta) in northern Vietnam. This is the first attempt to interpret the region's coastal depositional environments in the light of a geological model of Holocene environmental change recognising the interacting roles of Holocene sea-level change, alluvial responses to sea-level fluctuation, and tidal environment sedimentation. The coastal sediments overlie a Pleistocene land surface, and represent the Holocene marine transgression and regression. Prior to c .6000 bp , the sea rose to around or above its present elevation, converting the Pleistocene terrestrial landscape to a Holocene tidal landscape of tidal flat, channel and mangrove environments. Sea-level lowering by c .4000 bp triggered a switch in dominant sedimentary processes, allowing floodplain sediments to be deposited increasingly seawards. 相似文献
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John Kleinen 《Singapore journal of tropical geography》2005,26(3):339-358
This article discusses the relevance of the work of Pierre Gourou for Vietnamese and non‐Vietnamese scholarship on colonial and postcolonial rural society in Vietnam. The term “tropicality” is used to situate Gourou's work within the framework of both French and Vietnamese regimes of truth. It is argued that Gourou was aware of the complex human geographies of the tropics and monsoon Asia and the challenges this posed to both Western and “tropical” peoples. Gourou and the issue of tropicality is used to show that Vietnamese scholars did not completely reject French colonial systems of knowledge, and that decolonisation did not herald a complete shift in knowledge about rural Vietnam. Rather, since the 1940s there has been antagonism and accommodation between colonial and postcolonial, French and Vietnamese modes of knowledge production. While Gourou underscored the otherness of the tropics, and there are colonial overtones in his work, he had an immense influence on indigenous ethnography and geography in Vietnam and elsewhere in the formerly colonised world. The article traces this important influence and how it has been both questioned and affirmed since independence in the Vietnamese context. It is suggested that the humanistic approach that Gourou pioneered in his 1936 study of the Red River Delta of northern Vietnam has outlived and been able to overcome the setbacks and drawbacks of both colonial and revolutionary/Vietnamese politico‐intellectual projects. 相似文献
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The urban transition almost always involves wrenching social adjustment as small agricultural communities are forced to adjust rapidly to industrial ways of life. Large-scale in-migration of young people, usually from poor regions, creates enormous demand and expectations for community and social services. One immediate problem planners face in approaching this challenge is how to define, differentiate, and map what is rural, urban, and transitional (i.e., peri-urban). This project established an urban classification for Vietnam by using national census and remote sensing data to identify and map the smallest administrative units for which data are collected as rural, peri-urban, urban, or urban core. We used both natural and human factors in the quantitative model: income from agriculture, land under agriculture and forests, houses with modern sanitation, and the Normalized Difference Vegetation Index. Model results suggest that in 2006, 71% of Vietnam's 10,891 communes were rural, 18% peri-urban, 3% urban, and 4% urban core. Of the communes our model classified as peri-urban, 61% were classified by the Vietnamese government as rural. More than 7% of Vietnam's land area can be classified as peri-urban and approximately 13% of its population (more than 11 million people) lives in peri-urban areas. We identified and mapped three types of peri-urban places: communes in the periphery of large towns and cities; communes along highways; and communes associated with provincial administration or home to industrial, energy, or natural resources projects (e.g., mining). We validated this classification based on ground observations, analyses of multi-temporal night-time lights data, and an examination of road networks. The model provides a method for rapidly assessing the rural–urban nature of places to assist planners in identifying rural areas undergoing rapid change with accompanying needs for investments in building, sanitation, road infrastructure, and government institutions. 相似文献