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11.
关于生态用水研究的讨论 总被引:25,自引:2,他引:25
十几年生态用水研究进展,其概念从自然地理平衡说法到生态系统稳定说法,至今未明确统一。按生态用水概念的内涵,将生态、环境、生态环境与用水、需水、耗水6个词的多样组合归纳为生态需水和生态用水两个词。地带性植被生态用水是生态用水研究的基础,可为生态保护和植被建设提供依据和目标。建议生态用水概念定义为:维持各类生态系统正常发育与相对稳定所必需消耗和现存的水称为生态用水。 相似文献
12.
黄河三角洲自然保护区的酶活性季节特征一定程度影响了该地植被分布类型,为研究黄河三角洲自然保护区不同植被土壤酶活性的季节特征,分别选取碱蓬(Suaeda salsa)、柽柳(Tamarix chinensis)、芦苇(Phragmites communis)、刺槐(Black Locust)和高粱(Sorghum)5种典型植被作为研究对象,分别在4个季节采集不同深度土壤,测定土壤脲酶、过氧化氢酶、碱性磷酸酶、脱氢酶、蔗糖酶活性。结果表明,土壤脱氢酶活性规律表现为碱蓬>柽柳>刺槐>高粱>芦苇,其他酶活性总体变化规律表现为刺槐>柽柳>高粱>芦苇>碱蓬;在同一季节中,不同植被间酶活性存在显著性差异,柽柳和刺槐林土壤脲酶、碱性磷酸酶和蔗糖酶活性普遍高于其他群落,碱蓬最低;土壤酶活性与土壤基础理化指标有着密切关系,土壤过氧化氢酶活性、脲酶活性和蔗糖酶活性之间存在极显著性正相关(P<0.01),过氧化氢酶,脲酶和蔗糖酶与有机质、碱解氮呈显著性正相关(P<0.01),脱氢酶与速效磷呈显著性正相关与pH之间呈负相关(P<0.01);在0—... 相似文献
13.
植被作为反映陆地生态系统和气候的重要指标,对研究全球或区域生态环境变化具有重要作用。以地处黄土高原生态脆弱区的榆林市为研究区,基于地理探测器模型,选取坡向、坡度、气温、降水和土壤类型5类自然因子,土地利用类型、人口密度和GDP 3类人文因子,分析榆林地区植被空间分异特征及其驱动力,并揭示了促进植被生长影响因子的最适宜特征。结果表明,(1)研究区2000—2018年植被覆盖趋向改善,NDVI呈现增加趋势,增速为0.11/10a,2008年以后植被增长较为明显;NDVI在2018年中高等级(0.6—0.8)面积比2000年中高等级面积明显增加;中高等级集中于榆林市东部黄土丘陵区,中低等级(0.2—0.4)集中于榆林市西北部的风沙区,植被覆盖呈现东部高西北低的空间分布特征。(2)人口密度和气温因子较好地解释植被NDVI空间分异性,是影响NDVI空间分异性的主要因子,GDP、土地利用类型和坡度是次级影响因子,其他因子对NDVI空间分异存在间接影响;坡向、降水和土壤类型因子与其他自然、人文因素对植被空间分布影响存在显著性差异。(3)自然、人文因子对榆林市NDVI的影响存在交互作用,因子之间的交互... 相似文献
14.
SUMMARY Rainfall-surface water runoff relationships have been examined for 912 rainfall events during the 1992 and 1993 monsoon seasons on 15 erosion plots on a variety of non-cultivated land uses in the Middle Hills, Nepal. Vegetation cover and type examined ranged from grassland and relatively undisturbed mixed broadleaf forest to subtropical Sal forest, in various states of degradation, and bare ground. Runoff was frequently generated on most plots and often by relatively small rainfall amounts (less than 5 mm) and low rainfall intensities (3 mm/h). Ground cover and canopy cover were significant factors in determining amounts of runoff. Runoff coefficients ranged from 1–2% under grassland and mixed broadleaf forest to 57–64% on the bare sites. Coefficients for Sal forest were between these two extremes; specific values depended on the level of degradation induced by human activity. The most degraded forest sites experienced runoff coefficients of 33%. Ground cover beneath the trees, especially leaf litter, was more effective in reducing runoff than the amount of canopy cover. Canopy cover was more effective during the less intense storms but was ineffective when the rainfall intensity was high. The results suggest that a minimum ground cover of 60% will keep runoff to within 10% of total rainfall amounts for most normal monsoons in the Middle Hills. This will also reduce the risk of gullying and surface soil erosion. It is the nature of the forest that is important and not its total area. In the study area, although the total area under forest had not changed, some of the forest had become more degraded with a corresponding increase in mean runoff rates. Increased runoff can occur even if the area under forest increases. Estimates of levels of degradation based solely on changing forest areas are likely to be inaccurate. 相似文献
15.
Hye Kyung Lee 《国际发展与全球生态学杂志》2018,25(4):371-381
As green infrastructure gets its attention in hazard mitigation, it is necessary to improve general understanding on what makes green infrastructure important for hazard and resiliency research. To better understand how green infrastructure fits with more traditional notions of structural and nonstructural mitigation, this study examines the relationship between green infrastructure and ‘structural and nonstructural’ mitigation approaches for hazard mitigation. Also, this study discusses a new measurement of locational aspects and spatial patterns of green infrastructure by utilizing high-resolution data in urban areas, and its potential implementation in hazard mitigation. Compared to previous research using land-use land-cover datasets, the normalized difference vegetation index (NDVI) utilizing National Agriculture Imagery Program dataset provides an ability to capture green infrastructure in greater detail. A visual comparison suggests that the NDVI data are able to capture and identify more types of ‘green’ land uses in Harris County. The total green infrastructure percentages for Harris County, Texas, based on 1-m high resolution were found to be 61.5% of the area, compared to the 51.5% based on the National Land Cover Database. This study provides support for utilizing high-resolution data to establish guidelines for green infrastructure’s spatial characteristics and sustainable hazard mitigation. The outcomes of this study will be helpful in the strategic planning and implementation of green infrastructure in urban areas with hazard issues. 相似文献
16.
The effect of nitrogen on biomass production, shoot elongation and relative density of the mosses Pleurozium schreberi, Hylocomium splendens and Dicranum polysetum was studied in a chamber experiment. Monocultures were exposed to 10 N levels ranging from 0.02 to 7.35 g N m−2 during a 90-day period. All the growth responses were unimodal, but the species showed differences in the shape parameters of the curves. Hylocomium and Pleurozium achieved optimum biomass production at a lower N level than Dicranum. Pleurozium had the highest biomass production per tissue N concentration. Tolerance to N was the widest in Dicranum, whereas Hylocomium had the narrowest tolerance. Dicranum retained N less efficiently from precipitation than the other two species, which explained its deviating response. All species translocated some N from parent to new shoots. The results emphasize that the individual responses of bryophytes to N should be known when species are used as bioindicators. 相似文献
17.
地表水环境遥感监测关键技术与系统 总被引:1,自引:0,他引:1
介绍了地表水环境遥感监测的关键技术与系统及其典型应用,其代表性机理模型和应用示范成果主要来自于中国科学院遥感与数字地球研究所的高光谱遥感团队在最近几年中取得的一些研究进展,主要包括建立了基于改进双峰法的水体分布自动化遥感提取方法,实现了简单、高效和高精度的水体提取;提出了大型湖泊长时序水量估算方法,并以青藏高原湖区为例,重建了典型湖泊面积、水位和水量序列;发展了基于“软分类”的典型内陆水体叶绿素a浓度反演方法,构建了基于生物光学模型的高度浑浊水体悬浮物浓度遥感反演半解析方法,提高了反演方法的区域和季节适用性;构建了基于水色指数的大范围湖库营养状态和透明度遥感监测方法,实现了全球大型湖库营养状态遥感监测,以及全国大型湖库透明度遥感监测;在此基础上,开发了地表水环境遥感监测系统,提高了水环境遥感监测效率,促进了卫星遥感在水环境监测中的高精度业务化应用。 相似文献
18.
安太堡露天矿南排土场滑体植被治理技术 总被引:1,自引:0,他引:1
论述了安太堡矿南排土场滑体整治模式,通过植被减少滑体侵蚀及水土流失,改善了滑体的生态景观,对滑体安全起到了良好作用。 相似文献
19.
干旱与半干旱地区土地生产潜力的测定──以新疆阜康县为例 总被引:1,自引:0,他引:1
本文探讨了一个通过土壤有效水分含量来确定土地等级和土地生产力的方法。这个方法采用倍增参量形式来确定土壤有效水分。其变量包括潜水位、土层厚度、土壤质地、坡度和盐分。此项研究证明用这种方法获得的土地初级生产力与实测值比较一致。因此,我们可以在类似环境下用这种方法估测土地生产潜力。 相似文献
20.