长江平原区乡村景观的结构、管理及其对土壤氮磷的影响

通过实地研究主要位于宜兴市域的区域乡村景观代表性样方,评价并阐明了人口密集的长江平原区乡村景观的结构、管理与土壤全氮、全磷密度和储量的关系.景观绘图是基于1m分辨率的IKONOS影像并采用生态立地分类及绘图标准,通过直接解译和实地检验对均质景观缀块进行分类和绘图;依据区域权重分层取样方法,在生态立地缀块中随机设定取样点进行土壤或底泥取样;通过自助法对12个样方重取样,用区域多变量最优化方法计算样方的区域权重,并结合不确定性分析模型评价区域土地利用/覆被、土壤全氮和全磷储量.结果表明:在85.24×103km2的长江平原区乡村景观面积范围内,0～30cm土壤全氮、全磷储量分别为29.87Tg N和 19.79Tg P.最大的5种土地利用/覆被的类型为水田、水产养殖、非渗漏性建筑用地、旱地1年生作物和闲置水域,占区域总面积的82.9%;其土壤全氮、全磷储量分别占区域总量的82.6%和80.8%.其中平原稻田面积为38.93×103km2,占总面积的45.5%;其0～30cm土壤全氮、全磷储量分别高达15.26Tg N和9.13Tg P,分别占总储量的51%和45%.揭示了人口密集的乡村景观中土地利用/覆被方式对区域土壤全氮、全磷的影响模式.这种在小尺度下对土地管理调查,土壤全氮、全磷及其它生态特征研究方法的精确度明显优于传统的基于30～1000m分辨率遥感影像的土地覆被研究.     

论边坡的生态恢复

对裸露边坡采用植被防护的方式日益引起全球重视,但边坡植被恢复是一项比较复杂的工程,本文阐述了边坡植被的功能,生态恢复的原理,植物品种的筛选,边坡生态恢复的方法及应用,边坡生态恢复的发展方向。     

酸枣根系结构可塑性对自然梯度干旱生境的适应机制

根系是植物吸收水分和养分的主要器官,是直接接触土壤最先感受土壤逆境胁迫的部位。在干旱环境中,植物根系的结构特征必定发生改变以维持正常的生物机能而生存。目前,关于根系解剖结构的研究大多集中于根系的某一特定结构对单一逆境因子的响应。以生长在烟台-石家庄-银川-吐鲁番不同地域气候条件形成的自然梯度干旱环境中的酸枣为试验材料,应用植物显微技术研究酸根系结构的可塑性对不同自然梯度干旱环境的适应机制,结果表明:酸枣根的初生结构包括表皮、皮层和维管柱,表皮位于幼根的最外层,由单层体积较小、紧密排列的表皮细胞组成。皮层占根初生结构的大部分比例,由体积较大的多层薄壁细胞组成,薄壁细胞近似圆球形,数目众多,呈环形分布。维管柱位于最内层,细胞小而密集,由中柱鞘、初生木质部、初生韧皮部及薄壁细胞组成。随生境干旱加剧,酸枣根初生结构表皮细胞的厚度和宽度逐渐增加,皮层薄壁细胞的厚度和宽度、皮层薄壁细胞层数和皮层厚度均以宁夏银川样地的最大。酸枣根的次生结构包括周皮(木栓层、木栓形成层、栓内层)和次生维管组织(次生韧皮部、维管形成层和次生木质部)。从烟台至新疆吐鲁番随生境干旱加剧,酸枣植株根系周皮逐渐加厚、致密度提高。次生木质部中,导管的数量增加,管径增大。干旱环境中,酸枣植株根系结构上的变化一方面提高了吸水能力和输水效率,另一方面增强了保水能力,减少水分散失,这可能是其适应干旱逆境的机制之一。     

Ecotope mapping for landscape ecological assessment of habitat and ecosystem

An ecotope (spatial eco-space) map that considers topography and bio-organism-relevant variables emerges as an important basic framework when landscape-scale characteristics for ecosystem management and wildlife conservation are needed. A spatio-geoecological framework based on geographic information systems (GIS) and a vegetation survey were developed for wildlife habitat evaluation of national parks and applied to a representative rugged valley area of Mt. Sorak National Park in Korea. An ecotope map was classified into hundreds of types and dozens of groups by combining biological and geophysical variables. Variables included: forest vegetation type, topographic solar radiation, normalized difference vegetation index (NDVI), elevation, and anthropogenic factors, such as, streams and roads. Layers of GIS variables were produced by field surveys, modeling, satellite images, or digitalization. Vegetation surveys were carried out to identify finer-scale distribution of vegetation types in the rugged valley area. Digital forest vegetation maps from the Forestry Administrator were then modified using the field-surveyed vegetation maps. Topographic solar radiation was predicted with a daily topographic radiation model. The NDVI was calculated from the satellite imagery of a Landsat Thematic Mapper. A digital elevation model (DEM) was used and the other layers were digitized using topographical maps with a scale of 1:25000. The aim of this study is to determine the geoecological factors relating to the spatial pattern of plant community. It was cleared by the spatial pattern of environmental variables and vegetation characteristics by detrended correspondence analysis using plant species and the environmental variables of each plot. The ordination component value of the first axis shows significant regression to some environmental variables. A case study of habitat evaluation was carried out using the resultant ecotope map. The spatial distribution of potential goral habitat and vegetation characteristics were predicted and the impact of human trails on the neighboring vegetation was also examined for restoration planning. The GIS-based framework developed for wildlife habitat evaluation is useful for natural resource management and human activity control in national parks in Korea.     

间种蔬菜对甘蔗地生态环境和甘蔗生长的影响

甘蔗 (ＳａｃｃｈａｒｕｍｏｆｆｉｃｉｎａｒｕｍＬ .)是广西重要的经济作物 ,种植面积达 4 5 33× 10 6ｈａ[1] ,甘蔗的前期生长比较缓慢 ,行间有比较大的可利用空间 ,到6月下旬～ 7月上旬才进入迅速生长期并逐渐封行。有研究表明 ,在甘蔗园间种玉米对甘蔗的生长发育和产量有一定的影响[5] ,而合理间种豆科作物 (黄豆和花生 )不仅不影响甘蔗的正常生长发育 ,还可以增加甘蔗的产量[4 ,6] 。但间种作物对甘蔗园生态环境的影响未见报道 ,我们于 1997- 1999年在桂西北开展了甘蔗园间种经济效益比较高的蔬菜作物的试验 ,并对间种甘蔗园生态环…     

我国仓贮昆虫病原芽孢杆菌的研究

对９５１个样品分离鉴定,有７４７个样品含芽孢杆菌,有菌率为７８．５５％．共分离得到芽孢杆菌１１３８株,其中苏云金杆菌（Ｂａｃｉｌｌｕｓｔｈｕｒｉｎｇｉｅｎｓｉｓ,简称Ｂ．ｔ）１４３株,占１２．５％;球形芽孢杆菌（Ｂａｃｉｌｌｕｓｓｐｈａｅｒｉｃｕｓ,简称Ｂ．ｓ）１１株,占０．９７％;其他芽孢杆菌９８４株,占８６．４０％．从芽孢杆菌中选出产生晶体、苏云金素或磷酸酯酶Ｃ（ＰｈｏｓｐｈａｌｉｐａｓｅＣ,简称ＰＬＣ）的毒素菌株１６８株,其中Ｂ．ｔ占１４３株,Ｂ．ｓ有５株,其他芽孢杆菌１０株．在产毒素菌株中,经测定有１２０株菌对供试昆虫毒性达标．占７７．９２％．不同菌株的杀虫毒素、杀虫范围和毒力各异,认为这种差异取决于毒素和虫种两方面的特异性．     

中国典型丘陵区人口密集乡村景观的土壤碳氮磷分布特征

基于IKONOS高分辨率(1 m)卫星遥感图,根据生态立地分层分类规则,评价了四川盆地、江南山地和华南山地等典型丘陵区人口密集的乡村景观结构对0～30 cm土壤有机碳(SOC)、全氮(TN)和全磷(TP)密度及储量的影响.结果表明：SOC密度的面积加权平均值为江南山地丘陵(2.72±0.76 kg·m^-2) > 华南山地丘陵(2.65±0.73 kg·m^-2)>四川盆地丘陵(2.15±0.57 kg·m^-2);TN密度的面积加权平均值为江南山地丘陵(0.28±0.06 kg·m^-2) >四川盆地丘陵(0.27±0.06 kg·m^-2) >华南山地丘陵(0.21±0.06 kg·m^-2);TP密度的面积加权平均值为四川盆地丘陵(0.19±0.04 kg·m^-2) >江南山地丘陵(0.11±0.03 kg·m^-2)>华南山地丘陵(0.08±0.04 kg·m^-2).四川盆地、江南山地和华南山地丘陵SOC、TN和TP储量最高的生态立地类型分别为小规模1年生旱地作物、两季水田和斜坡次生阔叶疏林.SOC和TN密度均以水田或林地最高,而以低覆盖度的挖掘地和山顶旱地最低,TP密度的分布较为复杂.细微尺度的生态立地水平分析可以较好地反映出丘陵区人口密集乡村景观地区的生态结构和SOC、TN、TP的分布情况.     

长江下游平原区乡村景观的结构、管理和土壤有机碳研究

通过实地研究主要位于宜兴市域的区域乡村景观代表性样方,评价并阐明了人口密集的长江下游平原区乡村景观的结构,土地管理与土壤有机碳储量的关系。景观绘图是基于1m分辨率的IKONOS影像并采用生态立地分类及绘图标准,通过直接解译和实地检验对边界清晰的均质景观缀块进行分类和绘图;依据区域权重分层取样设计方法,在生态立地斑块中随机设定取样点进行土壤和淤泥取样;利用区域权重系数进行区域土地利用/覆被和土壤有机碳储量评价计算。结果表明:在2.13×106hm2的长江下游平原区乡村景观面积范围内,0~30cm土壤有机碳储量为76.97Tg。该区域土地利用/覆被的主要类型为水田,水产养殖,非渗漏性建筑用地,旱地1年生作物和水浇地多年生作物,这5种类型的面积百分数和土壤有机碳储量百分数分别为83%和85%。其中平原稻田面积为0.89×106hm2,占总面积的42%;其0~30cm土壤有机碳储量高达36.60Tg,占总储量的48%。通过区域分层取样和小尺度景观斑块的区域权重推绎分析,揭示了人口密集的乡村景观中土地利用/覆被方式对当地和区域土壤有机碳的影响模式。这种在小尺度下对土地管理调查,土壤有机碳和其它生态特征研究的方法明显优于传统的基于30~1000m分辨率遥感影像的土地覆被研究和基于土壤类型的区域土壤有机碳储量评价方法。     

Succession and Rejuvenation in Floodplains along the River Allier (France)

The spatio-temporal heterogeneity of a meandering part of the Allier river was studied by analysing ecotope composition and dynamics using a series of aerial images covering a period of 46 years (1954–2000). The ecotope dynamics was exemplified by two time series showing rejuvenating hydro-geomorphological processes, i.e., meander progression, meander cut-off and channel shift. The mean rejuvenation rate was 33.8 ha per 5 years for the 5.5 km long study area. The ecotope transition rates varied from 18% surface area change per 5 years to 58.7% surface area change per 5 years for pioneer vegetation. The combination of hydro-geomorphological processes and ecological succession resulted in a temporal diversity of the riparian area. In the year 2000 half of the total riparian landscape was 14 years or younger and 23% was not rejuvenated in 46 years. Eighty percent of the pioneer vegetation was found on young soils (<14 years) while more than 50% of the surface area of low dynamic ecotopes like bush and side channels was located on parts, which were stable for more than 46 years. Examining the relation between river stretch size and ecotope diversity showed that the ecotope diversity remained stable above a stretch size of 1.5 meander lengths for the years 1978, 1985 and 2000. The spatial and temporal analysis of the study area showed evidence supporting the steady state or meta-climax hypotheses, but influences of long-term processes on landscape composition were also found. Some implications for floodplain management are discussed.     

麦套春棉对棉花生态环境及生长影响的研究

对麦套春棉环境和棉株生长发育进行研究,结果表明：热、光、水资源的竞争是造成棉花苗弱、迟发的主要原因,其中热量尤为主要。因此,麦套春棉应采用地膜覆盖,增另有效地积温,以补偿作物层和耕层土壤热量亏缺。麦人生期,套种棉行生态环境和棉株生长发育显著受到小麦的遮荫和蔼和遮荫时间的影响。此种遮荫程度,随着小麦株高的增加而加重,随着麦棉间距的加大而减轻。遮荫时间也随着小麦成熟期的推迟而延长。因此,麦套春棉棉间距