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三峡库区山区传统农业生态系统转型 总被引：12，自引：1，他引：11
三峡库区是集农村、山区、移民区为一体的典型生态脆弱区,研究其传统农业生态系统的变化对于库区的农村发展与乡村振兴具有重要意义。通过“理论分析—实证研究—趋势预测”的研究框架,以草堂溪流域为例,利用2012-2017年的Quick Bird高分遥感影像结合自然资源要素与农户行为从空间尺度上人地关系变化角度出发对三峡库区山区传统农业生态系统的转型及趋势进行解析。研究发现：① 利用100 m间隔范围的缓冲环将三峡库区的农业生态系统模式分为高低低、高低高、低高低与低低高4种类型,不同模式分别代表三峡库区不同的农业发展阶段,揭示了库区传统农业生态系统由传统耕作方式向现代农业转型的趋势。② 库区的农业生态系统正逐步由传统的耕作区域内粗放利用的纯农生计方式,通过坡耕地撂荒、经果林种植等生态恢复方式,向聚落周边300 m范围内种植结构合理化、物种多样化的集约利用方式转型。③ 以农户与坡耕地等系统要素为代表的三峡库区传统农业生态系统正在发生转型。其中坡耕地多由生产功能主导向生态与经济功能并重转变,农户生计方式趋于多样化,聚落系统生态活力逐渐增强,且农业生态系统转型的变化范围基本由高海拔山地区域向河谷平坝区迁移。此外,尽管在数据时限方面存在不足,但研究结果对于库区乡村土地利用、山区水土流失治理及农村人居环境改善均有启示意义。 相似文献
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Al-Shami S A Che Salmah M R Siti Azizah M N Abu Hassan A Azmi M 《湿地科学》2006,4(4):241-246
1 INTRODUCTIONRice field is a unique man -made wetland envi-ronment where many varieties of aquatic insects oc-curred ( Ali, Ahmad, 1988; Yamazaki,et al,2001a; Che Salmah, Abu Hassan, 2002). Duringrice cultivation in Malaysia, herbicides are used in-tensi… 相似文献
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The Three Gorges Reservoir Area(TGRA)is typical of an ecologically vulnerable area,comprised of rural and mountainous areas,and with high immigration.Because of its economic and ecologic importance,studying the traditional agroecosystem changes in the TGRA is key to rural development and revitalization.In this study,we apply a framework of theoretical analysis,empirical study,and trend prediction to the Caotangxi River watershed within the TGRA.Using QuickBird high-resolution remote sensing images from 2012 to 2017 to evaluate natural resources and farmers’behavior,we analyze the transition and trends in the traditional agroecosystem in mountainous areas of the TGRA at spatial scale of the man-land relationship.We find that the agroecosystem in the TGRA can be divided into four modes using 100 m interval buffer rings:high-low-low,high-low-high,low-high-low and low-low-high mode where the different modes represent the agricultural development stages in the TGRA.Furthermore,the traditional agroecosystem in TGRA,represented by system elements such as farmers and sloping farmland,is transforming to accommodate the diversification of farmer livelihoods.For example,sloping farmland,which was dominated by a production function,now has equal emphasis on ecological and economic functions.Spatially,the range of the agroecosystem transition has migrated beyond high mountain areas to flat valley areas.Generally,this study provides an overview of land use in rural areas,controls on soil and water loss in mountainous areas,and better rural living environments in the TGRA. 相似文献
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This study explored the impacts of sustained heavy grazing in six vegetation types across an altitudinal and rainfall gradient in the Kamiesberg mountain range in Namaqualand. The study was carried out across the fence separating the Leliefontein communal area and surrounding privately owned farms. The communal area has been stocked over decades at approximately twice the government recommended stocking rate, while adjacent privately owned farms have generally adhered to recommended rates. Plant community data were collected from 66, 0.1 ha modified Whittaker plots and analysed for diversity and compositional changes. Consideration of community-wide responses through NMDS ordination showed that heavy grazing did not result in the dominance of a few wide-spread, weedy species in communal areas. Species richness at the 0.1 ha scale was also not affected by different land use practices. However, there was a significant compositional shift away from large woody and succulent shrubs, and an associated increase in dwarf shrubs and herbaceous perennial plants on the communal areas. This shift was only evident on the sandy lowland habitats, while a reduction in perennial grass was recorded in the rocky upland habitats on the communal areas. Compositional shifts towards smaller and more ephemeral species in the communal area are indicative of a system more closely dependent on rainfall. This has implications for people's livelihoods in the region, particularly in light of predicted climate change. 相似文献
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西藏乌柳群落特征 总被引：2，自引：0，他引：2
以一江两河流域为研究区,通过对西藏乌柳群落的典型地块设置11个标准地进行调查,分别从主要优势树种表现、物种组成、物种多样性、林分生长、地径结构、树高结构和树高-地径曲线等方面,分析了西藏乌柳群落的主要群落学和测树学特征。研究结构表明,1.西藏乌柳群落物种组成较为单一,群落中的物种数一般为1～4种,优势树种在群落中所占的比例较大,均大于85%;2.地径主要分布于5.0 cm以下,树高分布于1.0～5.0 m间,树高-地径服从二次曲线分布;3.由于群落物种组成较为单一,香农物种多样性指数均<1,SW和S、E的变化趋势大致相同,且与ED变化趋势相反。 相似文献
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以泉州湾河口湿地为研究对象,开展海陆一体化修复工程,包括滩涂红树植物种植和互花米草控制、鱼塘改造和退养还湿、海陆交错带植被修复等手段。通过评估植被和生境恢复情况,对比修复前后鹭科鸟类的群落组成变化,探讨滨海湿地修复对鸟类的生态作用和修复的有效性。结果表明:修复工程开展后,滩涂和鱼塘生境得到了改善;海陆交错带植被覆盖率和植被指数NDVI呈上升趋势;研究区内共记录到鹭科鸟类11种18164只次;与修复前相比,修复后第2年鹭类种类和数量均呈现一定程度的下降;修复后第4年鹭类数量显著增加。泉州湾河口湿地修复工程为鹭类提供了更多适宜的栖息环境,对鹭类多样性保护具有重要意义。 相似文献
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CheSalmahM.R WahizatulAfzanA. 《湿地科学》2004,2(3):184-191
Odonata larvae and adults were collected from fourteen sites of various habitats including rivers, rice fields, mountain streams, freshwater and peat swamps, oil palm, sugarcane and rubber plantations and lake. Out of 51 species recorded, Libellulidae made up the most dominant of 10 families followed by Gomphidae and Coenagrionidae. Other families were less common. Riverine and stream ecosystems were the most diverse, both with six families and 19 and 13 species respectively. In the rice fields, Libellulidae and Coenagrionidae were represented by 17 and seven species respectively. The poorest fauna of Odonata was recorded from a lake system. A few of libellulids were found to be pollution tolerant and widespread in distribution. Many odonate species were restricted to preferred habitats or water parameter gradients that could be used as bioindicators of respective habitats or parameters. 相似文献
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Ecological surveys were carried out to investigate the distribution and characterization of riparian corridor plants along the Perai River,Penang,Malaysia from July 2007 to March 2008.Surveys were design to represent horizon-tal sections of the river starting from the river mouth towards the upper reaches for 20 km.A total of 84 species of plants from 30 families were recorded.They consisted of 28 species of standing plants(plants with height of more than 1 m)and 56 species of weedy plants(plants with heigh... 相似文献
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Air-borne radio-echo soundings of sub-polar glaciers in Svalbard have previously been carried out by Soviet scientists using high frequency radar units of 620 and 440 MHz. Later a British/Norwegian group made soundings with 60 MHz equipment. The high frequency radar units seemed to underestimate the ice thicknesses. The 60 MHz radar unit seemed to give more accurate results when compared to areas with gravity surveyed bed. However, both the Soviet and the British equipment seldom recorded bed-echoes in accumulation areas where firn soaking during summer and thus zero temperatures are likely to occur. A low-frequency impulse radar unit of 8 MHz, however, recorded bed echoes in these areas too. In the accumulation area of Kongsvegen depths down to 440 m were recorded. The glacier bed is thus close to sea level at approximately 12 km from the calving front. Soundings were carried out on Brøggerbreen. Lovenbreen and Kongsvegen. Subglacial maps were generated from the data. Internal reflections that were probably caused by englacial drainage channels could be observed. Frequent internal reflections close to the bed could be interpreted as an indication of temperate ice. However, we could not find any distinct upper level of these reflections. 相似文献
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及时掌握水稻的时空分布信息,对调整和优化农业生产结构至关重要。论文利用综合考虑植被物候和地表水变化的水稻自动制图方法,结合海拔、地表水体因素开展2001—2017年东北地区水稻分布的时空演变研究。通过889个地面调研点位对水稻分类结果验证,总体精度达90.66%,Kappa系数为0.8128。研究表明:① 21世纪初,东北地区水稻种植面积呈先略减后持续增加的趋势,2017年水稻种植面积达2001年的2.13倍。其中,水稻扩张面积的60%分布在三江平原,30%分布在松嫩平原,下辽河平原仅占不足5%。水稻扩张的海拔优势区间在200 m范围内,随着海拔的上升水稻扩张与地表水关系越来越密切。② 三江平原内,水稻扩张幅度在海拔30~70 m范围内逐渐增加,使优势区间从相对高度70 m缩减至40 m内,也使得分布优势逐渐趋向于距地表水体较远的区域。而松嫩平原和下辽河平原水稻种植分布的海拔优势区间始终分别保持在相对高度100 m、40 m内。③ 三江平原水稻的集中分布和急剧扩张,使水稻分布优势逐渐趋向于距地表水体远的区域,这将对地下水带来更大的压力;而松嫩平原水稻分布受地表水体影响较大,分布优势随着距地表水体距离的增加而减小。研究可为农业部门评估水资源承载力、保障农业可持续发展提供数据支撑及理论参考。 相似文献
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中世纪暖期和小冰期是近2 000年气候变化中重要的气候事件,厘清其在低纬度地区干湿变化特征及其对古代农业发展及人口增长的影响,具有重要的意义。通过对广西柳州岩溶洞穴中一60 cm岩芯进行孢粉、炭屑分析发现,研究区的气候、稻作农业从唐末以来先后经历了6个阶段演化：1）875―940 a A.D.,C/P值及花粉记录指示：研究区气候整体偏干,水稻种植减少;2）940―1 050 a A.D.,C/P值及花粉记录指示：夏季风增强,水稻种植稍增长,人口增加;3）1 050―1 140 a A.D.,C/P值及花粉记录指示：夏季风减弱,稻作农业及人口较前期有所增长;4）1 140―1370 a A.D.,C/P值及莎草科花粉含量指示：研究区当时气候处于“中世纪暖期”温暖湿润期,稻作农业面积扩大,人口增加;5）1 370―1 900 a A.D.,C/P值及莎草科花粉含量指示：“小冰期”气候变干,水稻种植及人口逐渐减少;6）1 900―2 009 a A.D.气候变暖湿,水稻种植扩大,人口迅速增长。进一步对研究区气候事件与稻作农业及人口关系研究发现：历史时期气候事件与水稻种植、人口具有耦合关系,即中世纪暖期,气候暖湿,水稻种植扩大,人口增殖;小冰期,气候冷干,水稻种植萎缩,人口锐减。在非原地沉积时,莎草科和C/P 对水分反映敏感,可以用来指示气候干湿变化。 相似文献
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近20年气候变暖对黑龙江省水稻增产的贡献 总被引：35，自引：1，他引：34
研究过去的气候变暖对作物产量的影响是认识变暖对农业影响的有效途径,但如何定量区分出气候变化和技术发展对粮食作物的影响程度是目前研究的难点。本文提出的算法在一定程度上可以克服传统算法缺陷,用此方法估算过去20年气候变暖对黑龙江省水稻单产增加的贡献率,结果表明：20世纪80年代相对于70年代水稻单产增加了30.6%,其中由气候变暖带来的增产量占实际增产量的12.8%~16.1%,相当于使70年代的单产增加3.9%~4.9%。20世纪90年代水稻单产较80年代增产42.7%,其中,气候变暖对单产增加的贡献率约为23.2%~28.8%,相当于在20世纪80年代的单产水平上增产9.9%~12.3%。 相似文献
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不同作物下的土壤水盐运动分析 总被引：9，自引：0，他引：9
通过１９９５，１９９６年在阿克苏水平衡试验站对不同种植作物的土壤水分，盐分取样分析，显示不同情况下盐分运动规律差异很大，呈现出干旱区土壤盐分含量高，活动强烈的特征。 相似文献
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Arid Australia exhibits a rich and ecologically diverse snake fauna that has largely been overlooked by researchers. Here, I report on the results of an intensive road-cruise study carried out in the MacDonnell Ranges bioregion. I examined the effectiveness of the technique for sampling snakes, the influence of weather variables on snake activity, and the magnitude of road-kill in the region. Over 12 months and 11 858 km of sampling I encountered 375 individual snakes, including all 15 species previously known from the study area, establishing the effectiveness of this technique in the region. Although snake activity was constrained by cooler weather over the winter months (particularly June–July), rainfall was a stronger determinant of activity over most of the year, with increased precipitation resulting in increased snake activity. Future inventory-type surveys should be carried out over the summer months (December–February) when most species are active and substantial rainfall events (>40 mm) are more likely to occur. Road-kill snakes comprised only 9% of all snakes encountered, suggesting that road-mortality is not currently inflicting substantial damage on the regional snake fauna. 相似文献
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生物土壤结皮对荒漠昆虫多样性的影响 总被引：10，自引：6，他引：4
生物土壤结皮广泛分布在干旱半干旱地区与寒区荒漠,是荒漠生态系统的主要组成和景观特征之一,其重要性已被大量的研究报道所证实。然而,关于生物土壤结皮与昆虫种类多样性之间关系的研究却很少。本文以腾格里沙漠东南缘的沙坡头地区半固定沙丘柠条－油蒿群落和固定沙丘柠条－油蒿群落为观测样地,选择具有不同类型生物土壤结皮分布的植被群落为观测样方。昆虫的调查采用100 m×100 m的样方,利用样筐和网捕法收集昆虫,记录昆虫数量,采集标本在室内进行鉴定。结果表明:与无结皮覆盖的植被区相比,生物土壤结皮在地表的覆盖显著地增加了昆虫的多样性和种的丰富度,其中以苔藓和地衣为主的结皮覆盖的植被样方中昆虫种的多样性和丰富度显著地高于以蓝藻和藻类为主的结皮样方。生物土壤结皮对荒漠昆虫多样性的贡献可能是由于稳定了土表、改善了植被系统中的土壤环境,为昆虫,特别是幼虫阶段提供相对适宜的土壤生境或部分食物来源。 相似文献
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新疆阿克苏地区盐化潮土盐分组成为硫酸钙类型。具有面积大，连片分布的特点。虽然盐分具有一定的表聚性，但表聚程度较弱。从盐化潮土在阿克苏地区的分布，盐分在土壤剖面的分以及塔里木河流域水资源合理利用的角度而言当地通过种稻洗盐改良盐化潮土的作法是不合理的。 相似文献
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基于水位控制的黄河三角洲退化滨海湿地恢复及其短期效应 总被引：1，自引：1，他引：0
针对黄河三角洲滨海湿地严重退化盐碱化问题,于2015年5月设计实施了微地形改造营造和水位控制相结合的生态恢复方案,并评估了恢复工程的初步效果。结果表明:生态工程实施3个月后,恢复区植被、水域和裸地面积发生显著变化,植被比例从18.8%上升到30.5%,水域比例从7.4%上升到53.2%,裸地面积从73.8%降低到16.3%,湿地的改善为鸟类提供了多样化的生境。底栖动物从无到有开始拓殖,至2015年9月已发现大型底栖动物14种。自2015年9月至2016年3月,共有35种鸟类,包括13种重点保护鸟类在该区域栖息觅食。相对于简单围封补充淡水的传统恢复方式,本研究设计的生态恢复方案效果更为显著,在该区的生态恢复和重建中具有一定的推广价值。 相似文献
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通过调查厦门市下潭尾滨海湿地红树林生态修复区的鹭科鸟类物种和数量,对比海水不同潮位鹭科鸟类数量、生境分布以及红树林不同修复阶段白鹭种群数量变化,探讨红树林生态修复对鹭科鸟类种群动态的影响。2018—2019年在修复区共调查记录到8种鹭科鸟类,秋冬季鹭鸟种类较多,5—6月鹭鸟数量最多,其中白鹭为优势种;与修复初期相比,修复区在修复完成后的白鹭种群数量明显增加;修复区鹭科鸟类在海水低潮位时主要觅食于潮间带滩涂,在高潮位时大多数停歇于未被海水淹没的红树林,观察发现一些鹭鸟在繁殖季节营巢于高大的红树林。结果表明,滨海湿地红树林生态修复能够改善鹭科鸟类栖息环境,增加修复区的鹭科鸟类数量。 相似文献