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从辽宁省东部山区泥石流暴发的特点看，暴雨只是泥石流发生的一个激发因素。泥石流活动区分布于地壳快速上升，地震活动频繁的地带，泥石流活动的高潮与该区地震活动期基本一致，由此说明辽宁东部山区泥石流其孕育、发展和活动主要受内力地质作用所控制． 相似文献
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采用资料分析、现场踏勘、重点详查与座谈访问相结合的方法,依据国家标准GB/T 18972-2003《旅游资源分类、调查与评价》,对海南自然旅游资源进行调查、分类与评价研究。结果表明:海南自然旅游资源有4个主类、16个亚类和61个基本类型,涵盖了全国的绝大部分种类;自然旅游资源单体335个,特品级旅游资源单体47个,占总数的14.0%,优良级旅游资源单体178个,占53.1%,普通级旅游资源单体48个,占14.3%,未获等级旅游资源单体62个,占18.5%,形成一海(中国南海)、两极(海口市和三亚市)、三区(海南岛东部海岸、中部山区、西部海岸)的空间分布格局;中部山区、东部海岸和三亚市的自然旅游资源相对集中,组合搭配和特色性突出。海南自然旅游资源优势为拥有世界一流的热带海岛气候资源和热带海岸带资源,我国垄断的冬季避寒资源,我国面积最大的海域和最丰富的热带森林资源,热带温泉资源丰富,自然旅游资源珍稀性明显,而最具优势和竞争力的旅游资源是拥有中国和世界一流的优美生态环境。劣势是品牌旅游资源少,开发利用程度低,基础设施差,资源分布不均衡且有所重复,局部热带森林资源和滨海岸线生态系统遭到破坏。 相似文献
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３０年来我所在山区开发研究方面承担过国家级、院省部级重大科研任务３０余项，发表论著２００多种．研究领域有：山区综合开发，山区农业发展布局，山区资源条件评价及开发潜力，山区城镇和工业发展布局，山区人口的就业、移民和人口容量等．前两者是主要的． 相似文献
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吉林省东部山区耕地动态变化研究--以延边朝鲜族自治州为例 总被引：5，自引：1，他引：5
分析吉林省东部山区1978～1998年耕地数量的动态变化趋势和20世纪80年代中期(1986年为例)至90年代中期(以1996年为例)的土地利用类型转化，使用相关分析和层次分析法(AHP)对引起东部山区耕地数量和质量变化的自然方面、社会方面以及经济方面各因素进行分析，指出东部山区耕地变化的主要驱动力因子是人口因素、农业投入水平、市场导向和居民消费水平；新的发展形势下，耕地的压力仍然存在。该区应在保障粮食供给的情况下调整农业内部结构，发挥森林资源和野生动植物资源的优势，大力发展森林种植和养殖，同时积极发展森林旅游，缓解耕地压力，促进社会经济的持续发展。 相似文献
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东北山区湿地的保育与合理利用对策 总被引：10，自引：5，他引：10
大、小兴安岭和长白山区是东北湿地的主要分布区之一。山区湿地面积452．31万hm^2，以沼泽湿地为主，占山区湿地总面积的76．71％，分布着特有的中营养和贫营养沼泽。山区大面积的森林和湿地是保护东北平原农牧业生产及生态环境的重要天然屏障。在分析湿地主要生态功能及保护利用现状的同时，提出增设湿地自然保护区、加强保护区的有效管理和能力建设、实施对湿地开发项目的生态环境影响评价、建立湿地生态监测试验站、加强湿地科学研究、可持续利用湿地资源及增强湿地保护的经济活力等建议。 相似文献
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我国长江流域分布着约１００种槭属植物，占世界槭属植物种类的二分之一．长江流域槭树的地理分布，横断山区有１７种，峨眉山有２６种，庐山有１３种等。同时对庐山、黄山、南京、苏州、杭州、上海等地，作为城乡绿化美化的风景树种，槭树的栽培和置景概况作了介绍．最后，提出槭树资源的开发利用４条建议． 相似文献
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选取贡嘎山区３５种主要植物群落，对它们的垂直分布与水分、温度条件进行了分析。结果表明，贡嘎山区水分条件较好，温度条件是植物群落垂直分布的限制因子，亚高山针叶林，针叶阔叶混交林，常绿阔叶林的分布上限，其温暖指数，生物学温度分别为８－１２１，４０，６０－６８（℃·月）和３．０－３．５，６．５－７．０，９．０－１０．０（℃）。 相似文献
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调查的基础L，统计了太岳山种子植物有97科、316属、575种（含变种），分析了该区系的主要特征，即植物区系地理成分复杂，温带成分占优势；植物资源种类丰富，区系起源古老；植物区系具明显的过渡性；植被类型复杂，具明显的垂直分布．对该区野生经济植物进行了分类统计，为植物资源合理利用与生物多样性保护提供了基础资料穹科学依据． 相似文献
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在分析胶东半岛东部饮用天然矿泉水资源形成的地质背景的基础上，对矿泉水资源的基本特征，形成机制与分布规律进行了探讨，胶东半岛东部饮用天然矿泉水资源丰富，水质优良，具有优越的开发环境条件，矿泉水开发已产生较好的社会，经济效益，今后应面向国际市场，多渠道综合开发矿泉水资源，同时要加强矿泉水资源的管理与水源地环境保护。 相似文献
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M.A. Munguía-Rosas M.E. Jácome-Flores V.J. Sosa L.M. Quiroz-Cerón 《Journal of Arid Environments》2009,73(4-5):578-581
Myrmecochory sensu stricto is uncommon in Neotropical forests. In these ecosystems the role of ants as secondary dispersers of non-myrmecochorous seeds is well known, however, the primary dispersal of this type of seed by ants has been poorly documented. Only a few anecdotal observations scattered throughout the literature report the removal of these seeds from fruit on the plant by ants. We show experimentally that ants are able to remove more pulp and seeds from fruit on the branches than do flying vertebrates in Pilosocereus leucocephalus, a columnar cactus bearing typically ornithochorous fruit. In addition, experiments emulating seed cleaning revealed that cleaned seeds germinate earlier. These results suggest a possible role of ants as primary cactus dispersers; one that requires more extensive research on seed fate and seedling establishment success. 相似文献
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In desert ecosystems, selective foraging by seed consumers affects distribution and composition of soil seed banks, influencing plant population dynamics. However, the roles of consumers in burned habitats where direct seeding is used during ecological restoration to replenish depleted seed banks have not been well established. We evaluated seed removal for nine seed species over 12 months in burned and unburned shrublands in the Mojave Desert, USA. Percentage of total seed removed was highest during spring (16% of offered seed) and summer (21%). Rodents removed much of the large-seeded Coleogyne ramosissima in both burned and unburned habitats, while seed removal of this species by ants was low in burned and moderate in unburned habitats. Ants removed the greatest amount of small-seeded species (Penstemon bicolor, Encelia farinosa, and Sphaeralcea ambigua) in unburned habitat, indicating that ants can exploit different seed masses. Seed removal imposes limitations on seed availability, particularly for large-seeded species, as both rodents and ants selected seeds of C. ramosissima. Successful restoration seeding projects in arid lands may require protecting seed from granivore pressure, and seed species selection and season of seeding warrant consideration to reduce seed loss. 相似文献
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The diet of a species can help us to understand its natural history, ecological requirements, and strategies involved in searching for food. Liolaemus pseudoanomalus is a rare desert lizard where previous studies showed no seasonal, ontogenetic or sexual differences observed in microhabitat use; however the sexual dimorphism is evident in the number of precloacal pores and in the snout-vent length. In this work, we investigate if there are differences in the diet composition between sexes and age groups. Herein we describe the diet of L. pseudoanomalus, of the Central West Monte desert of Argentina, based on the analysis of 63 stomach contents. We found that ants are the most important food item and some characteristics of foraging behavior suggest similarities with other ant-eating lizards. 相似文献
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Studies of assemblages of insects that have largely agonistic relationships with plants are rare compared to those that study mutualistic relationships between plants and animals. Flowers have evolved multiple defense mechanisms to protect against nectar-thieving ants, which may decrease plant reproductive success. We evaluated season-specific patterns of biodiversity as well as trophic and temporal niche overlap for flower-visiting ants in the Brazilian Caatingas (dry scrub, tropical vegetation). Ant richness and evenness did not vary with season; however, Shannon diversity and Berger–Parker dominance were greater and lower, respectively, during the green season compared to the dry season. Trophic overlap was greater during the dry season than the green season. In contrast, temporal overlap was greater during the green season than the dry season. The most common flower-visiting ant (Camponotus blandus) exhibited season specific trophic and temporal niches. Flower-visiting ants exhibited seasonal complementarity, but within seasons species exhibited both trophic and temporal overlap, suggesting that competition for floral resources is not a strong structuring force in this guild. 相似文献
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岷江卵石推移质泥沙与数量特性 总被引：2，自引：0，他引：2
根据区域地质与地貌及其对卵石岩类组成的影响，将岷江下游卵石来源分为三个补给区及汇合区，用各补给区与汇合区的卵石岩类鉴定资料建立计算模式，计算出来自大渡河补给区的卵石占４０．６％，来自岷江上中游补给区占３６．１％，来自青衣江补给区占２３．３％。大渡河补给区卵石汇入百分数为已知，其龚咀水库的卵石数量为６．７７×１０５ｔ／ａ，据此计算出岷江干流卵石数量为１．６６８×１０６ｔ／ａ。该计算数同用卵石磨损方法求出的数值相近。验证表明，计算值与验证值两者只相差１．９％。 相似文献
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Ants of the speciesMessor arenariusandM. ebeninusare known as common granivores in the deserts of the Middle East and North Africa. The relationship between the spatial distribution of nests of these ant species and the distribution of vegetation was examined in the Negev highlands. Using the method of nearest neighbour analysis, it was found that nests ofM. arenariusare evenly dispersed while the dispersion of nests ofM. ebeninusdoes not differ from a random distribution. It is suggested that in desert surroundings there is a connection between the distribution pattern of nests of harvester ants and their foraging type. It seems that nests of individually foraging ants are usually evenly dispersed while nests of trunk-trail foraging ants are usually distributed in a random or aggregated dispersion. 相似文献
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C.S. Brehme W.I. Boarman S.A. Hathaway A. Herring L. Lyren M. Mendelsohn K. Pease M. Rahn C. Rochester D. Stokes G. Turschak R.N. Fisher 《Journal of Arid Environments》2009,73(9):811-820
We documented changes in the abundance and composition of terrestrial flora and fauna with respect to distance from the sea edge and timing of large allochthonous inputs from the Salton Sea, California. We found significant effects that were most pronounced within 300 m of the shore, but extended 3 km inland via coyote scat deposition. The zone within 300 m of the sea had a higher density of vegetation with a distinctly different plant composition. The denser vegetation supported higher abundances of birds and reptiles. Coyotes exhibited spatial and temporal responses to marine subsidies of fish, while birds were likely subsidized by aquatic aerial insects. Top-down control, as well as dietary and habitat preferences, may have resulted in reduced number of ants, beetles, and small mammals near the sea. Species responses to the habitat edge appeared to be associated with life history, as the near shore habitat favored habitat generalists and shore specialists, while inland desert habitat favored many sand and open desert specialists. Ecosystem responses support current theories of allochthonous spatial subsidies and consumer-resource dynamics but were limited in scope, magnitude, and distance. 相似文献
