采取得力措施 促进江西水保工作全面提高     

孙用和 《中国水土保持》1997,(11):1-5

<正> 1 10年来我省水土保持工作的成绩1.1 水土流失综合防治速度加快,生态环境明显改善我省坚持把水土流失治理作为发展经济和帮助群众脱贫致富的一件大事来抓,科学规划,精心组织,强化领导,明确职责,全省水土流失防治工作蓬勃开展,为改善生态环境发挥了重要作用.据不完全统计,10年来,全省共治理水土流失面积140多万hm~2,完成高标准重点治理面积22.67万hm~2.其中修建水平梯田10多万hm~2,建设水土保持林110多万hm~2,种草1.86万hm~2,发展经济果木林12万hm~2.“六五”期间每年完成6.2万hm~2水土流失治理任务,“七五”期间每年完成13.3万hm~2,“八五”期间每年完成20万hm~2,治理速度显著加快.兴国县自1983年列入国家重点治理县以来,经过10多年的治理,年土壤流失量由1160万t减少到460万t,山地土壤有机质提高2倍以上,全氮含量提高1倍以上;强度流失区治理后夏季地表最高温度平均下降8℃,冬季上升3.6℃,空气湿度提高6倍;山地植被覆盖度由28.7%上升到72.2%;全县几条主要河流河床平均下降0.26m,蓄水量每年增加2.3亿m~3,作物有效灌溉面积扩大1800hm~2,复种指数由145%提高到245%.  相似文献   

水库消落带应算作破坏水土保持设施面积   总被引：1，自引：0，他引：1       下载免费PDF全文

吴良喜  曾红娟 《水土保持通报》2007,27(4):141-143

水库蓄水长时间淹没和浸泡,致使水库消落带的植被几乎全部死亡,坡面土壤流失贻尽,岩石滑塌甚至造成山体不稳,引发滑坡等侵蚀。水库消落带不仅仅应算做水库建设的扰动面积,而且应算做破坏水土保持设施的面积,尤其在我国植被生长良好的南方地区。水库消落带破坏水土保持设施面积应该是正常蓄水位以下水库面积与未建水库前水面面积之差,面积大小可以采用面积量算法和简单估算法得到。  相似文献   

Bats in a fragmented landscape: Species composition, diversity and habitat interactions in savannas of Santarém, Central Amazonia, Brazil     

Enrico Bernard 《Biological conservation》2007,134(3):332-343

Species response to forest fragmentation may strongly vary according to ecological requirements, shape, spatial configuration and connectivity of fragments, and the structure of the surrounding matrix. Bats are natural candidates for studies on forest fragmentation. However, the conclusions of such studies are often contradictory. We present the results of a study on the effects of forest fragmentation on bat communities in Alter do Chão, Santarém area, in Central Amazonia, Brazil, an area composed by forests and fragments surrounded by savanna-like vegetation. We compared the species composition between habitats, tested the effect of size, shape and density of trees of forested areas on the presence species and their relative frequency of captures, and investigated the savannas as an ecological barrier for the dispersion of bats. With an effort of 5678 mistnet-hours, we captured 3740 bats (64 species). Multidimensional Scaling indicated no strong separation between the habitats sampled, however, savanna sites were grouped distinctly of fragments and forest sites. Multiple linear regressions indicated no significant correlation between the number of bat species recorded and the size, shape or tree density in forest sites and fragments. There was a significant correlation between the number of captures and the variables tested, explained by the shape of the sites, but not by size or tree density. In general, sites with bigger shape indices had fewer captures. Ten of the 20 most captured species showed no significant difference between the three habitats. The bat communities in Alter do Chão were not strongly affected by forest fragmentation, and the savannas did not appear to act as an ecological barrier to bats.  相似文献   

Molecular characterization of emmer (Triticum dicoccon Schrank) Italian landraces     

G. Barcaccia  L. Molinari  O. Porfiri  F. Veronesi 《Genetic Resources and Crop Evolution》2002,49(4):417-428

Emmer (Triticum dicoccon Schrank,2n = 4x = 28) is a hulled wheatspecies [more] widely spread in the Mediterranean basin. In Italy it survives as acrop in a few marginal areas and peculiar ecological niches in different regionsof central and southern Italy. A renewed interest has occurred during the lastdecade toward local varieties belonging to this species. As a matter of fact,local varieties have the highest genetic variation and adaptation to the naturaland anthropological environment from where they originated. Results on thegenetic diversity within and relationships among 11 Italian local varieties ofemmer as assessed with 17 RAPD marker loci are here reported. The proportion ofthe among-local variety genetic diversity was as high as 48% (G_ST =0.479). Thus, about 52% of the total variation was within population. Localvarieties of emmer proved to be formed by a variable number of lines geneticallydistinguishable from each other, and the vast majority of individuals overpopulations proved to be different multilocus genotypes. Landraces of emmer fromcentral and southern Italy showed distinctive molecular traits. In particular,local varieties classified as «Central Italy» types were characterized by a common set of RAPD marker alleles and proved to bedistinguishable from both the «Southern Italy» and the«Garfagnana» accessions. The overall results confirm the highvariability that can be found within landrace populations, underlining thevalues of landraces as an irreplaceable bank of genetically diversified andhighly co-adapted genotypes. Information for an appropriate insitu conservation and management of this valuable source of emmergermplasm is discussed.  相似文献   

Beyond the wetland border: Estimating the impact of roads for two species of water snakes     

John H. Roe  Joanna Gibson 《Biological conservation》2006,130(2):161-168

We used models integrating road maps, traffic volume, and snake movements to examine the potential for roads to contribute to mortality in two species of water snakes that differ in their vagility, use of terrestrial habitats, and conservation status. Road networks and traffic volumes typical of three regions in Indiana, USA, may account for mortality of 14-21% of the population per year in the more vagile, terrestrial, and imperiled copperbelly water snake (Nerodia erythrogaster neglecta) but only 3-5% mortality in the more sedentary, aquatic, and common northern water snake (Nerodia sipedon). The majority (>91%) of road crossings and associated mortality are predicted to occur during overland migrations to other wetlands, suggesting roads bisecting travel routes between wetlands may function as mortality sinks. Our models highlight the proportionately greater risk of mortality for the more vagile and imperiled species, N. e. neglecta, and suggest current wetland conservation strategies that focus on the wetland alone are unlikely to adequately protect wetland biodiversity from certain types of anthropogenic habitat modification. What is needed is a landscape approach to wetland conservation that considers not only the quality of wetlands and nearby terrestrial habitats, but also ensures that terrestrial corridors between wetlands remain permeable and offer safe passage for wildlife.  相似文献   

The occurrence of primary burrowing crayfish in terrestrial habitat     

Shane M. Welch  Arnold G. Eversole 《Biological conservation》2006,130(3):458-464

A researcher’s perception of a target species’ landscape strongly influences the design of habitat studies conducted at broad spatial scales. Consequently, researcher-dependent perceptions may misguide conservation efforts. Although the life histories of some crayfish (i.e., primary burrowers) are centered on a fossorial existence independent of surface water, all North American crayfish are viewed in an aquatic context. This paradigm restricts the range of habitats that are typically sampled and managed for crayfish conservation. This study used presence/absence of the primary burrower Distocambarus crockeri at 137 locations within the Long Cane Ranger District of the Sumter National Forest, South Carolina, USA, to model the habitat association of the species across a GIS-based landscape. Logistic regression indicated that D. crockeri presence was most strongly associated with a terrestrial habitat defined by a set of morphologically similar soils located along ridge tops. Furthermore, the species was negatively associated with aquatic habitats such as streams and floodplains. The results indicate that D. crockeri is a terrestrial habitat specialist and should be modeled and managed at the landscape as a terrestrial organism. When viewed as a subset of the total United States cambarid fauna, primary burrowers are disproportionately imperiled. Primary burrowers comprise only 15% of the total crayfish fauna, while they account for 32% of those crayfish ranked critically imperiled. Habitat loss and an aquatic bias that restricted sampling to aquatic and semi-aquatic habitats might explain the group’s disproportionate imperilment.  相似文献   

Segetal and ruderal relatives of cultivated plants and the problems of their conservation and use: a Russian perspective     

T. N. Ul'janova 《Genetic Resources and Crop Evolution》1997,44(1):5-8

The paper presents a survey of the situation existing now in nature with wild relatives of crop species from the group of segetal and ruderal plants, found within the territories of Russia and of other CIS countries. The majority of non-specialized annual and perennial weeds have been shown still to occur in the territory of the former USSR. For the past 50 years they have not seriously vanished from agriculture. Some of them even have a tendency to expand their areas and to become more abundant. Hence they need not be conserved in gene banks. It is only for a relatively small group of species of specialized contaminants that care should be taken to preserve them and to store their seeds in gene banks.  相似文献   

基于分布式水文模型的水土保持水文水资源效应研究   总被引：1，自引：4，他引：1       下载免费PDF全文

王浩  杨爱民  周祖昊  严登华 《中国水土保持科学》2005,3(4):6-10

 以往水土保持水文水资源效应研究所采取的方法均为水文法和水保法。由于这2种方法都不能系统地揭示水土保持对水循环影响的物理机制,并且采用的水资源评价口径只是单一的狭义水资源,使得研究成果不能真实反映水土保持的水文水资源效应。以狭义水资源和广义水资源为评价口径的基于物理机制的分布式水文模型则能克服水文法和水保法的严重弊端。评述分布式水文模型的研究进展;应用基于物理机制的分布式水文模型(WEP-L模型),以黄河流域的重点水土流失治理区——河口镇至龙门区间为例,对水土保持的水文水资源效应进行定量研究。结果表明:水土保持使广义水资源量增加72．6亿m3,增幅27．1％;使狭义水资源量减少9．0亿m3,减幅14．4％;使狭义水资源的构成发生了变化,即地表水资源量减小、不重复量和地下水资源量增加。  相似文献   

平托花生在红壤果园的水土保持作用与综合利用研究   总被引：7，自引：0，他引：7  

黄毅斌郑仲登  黄秀声陈恩应朝阳  唐龙飞 《水土保持学报》2004,18(6):30-33

果园套种平托花生具有良好的水土保持作用,连续4年定位测定表明,套种平托花生的果园发生地表径流38次,径流总量61t/hm2,无泥沙流失;而对照处理发生地表径流178次,径流总量2482 4t/hm2,流失泥沙42 26t/hm2。平托花生还有改善土壤理化性状的作用,果园套种平托花生3年后,0～20cm的土壤容重为0 98g/cm3,土壤空隙度25 73%,土壤含水量22 5%;而对照分别为1 06g/cm3,18 6%,21 5%。套种平托花生3年后土壤pH值从5 12提高到6 25,酸性改善;有机质从15 26g/kg提高为19 30g/kg;全氮从0 79g/kg提高到1 04g/kg;全磷从0 25g/kg提高为0 30g/kg;但全钾从23 23g/kg下降到19 64g/kg。平托花生营养丰富、适口性好。以平托花生喂养肉兔,平均日增重为21 67g,高于饲喂野生杂草(10 73g)。平托花生以扦插繁殖为主,采用10cm×10cm的扦插距离,在山地(有机质5g/kg)30天后覆盖度达到49%,45天达到87%,60天达到91%;而园地(有机质15g/kg)30天就可以达到80%。采用20cm×20cm的扦插距离,山地需75天达到80%的覆盖,园地75天达到89%。  相似文献   

水土保持林体系研究的回顾   总被引：2，自引：0，他引：2       下载免费PDF全文

郭浩  范志平 《中国水土保持科学》2004,2(1):97-101

 水土保持林体系是防护林体系中重要的组成部分之一,在改善生态环境、防治水土流失中具有重要作用。回顾国内外水土保持林体系研究的发展历程,并就其主要成就和存在问题进行简要评述。奥地利、前苏联、中国,在水土保持林体系科研方面成绩突出,起到了带头作用。奥地利建立的森林工程措施综合治理体系,已被许多国家采纳和推广。前苏联在土壤侵蚀及水土保持林作用机制方面的研究,已成为各国水土保持林体系研究和营造的理论依据。我国提出的生态林业和生态经济型水土保持林理论,是对世界水土保持林体系发展的一大贡献。目前存在的主要问题是研究尺度小、林分稳定性差、无合适理论依据和空间配置不合理等。正确解决这些问题,应是未来水土保持林体系研究的方向。  相似文献