台湾泥岩地区不同刺竹林景观下之土壤与植被变异

台湾西南部泥岩恶地,由于其特殊之土壤,地力流失消耗与区域微气候型态之间的因果循环,在水土保持与景观上形成不易植生绿化的地区及特殊之世界地形。泥岩地区之不同刺林林相之土壤,其林相皆伐后复层植被区土壤性质变异高于其它位置,而其它区之土壤理化性质在时间及空间上之变异不大,可明显区分林相不同之显著差异。不同林相对泥岩地浅层土壤(0~20cm)理化性质的差异,以植物营养元素与植生覆盖因子可充分说明(约占变异范围之62%)。泥岩试区区中移动性物质(交换性钙、钠与镁)明显较少出现在复层林相处区,而易出现于淋洗、冲蚀量较大之刺林相保留区与隔丛择伐区。长效性植物营养元素因子(pH值与有效性磷),因长时间之林相不同,使其较明显趋于复层林相区堆积,并影响地表植生之种类、分布与覆盖情形。0～20cm土壤性质的分布和离子间的移动特性有关,移动性高的钠、镁离子会在冲蚀量高之区域出现,20～40cm土壤性质的分布则和土壤中之母质与植生有关并与因素分析结果相似,其次为可移动性离子的影响,且应用地理统计印证土壤性质在空间之变化,其分布确实与不同林相位置有关,即植生营养元素(pH值、有效性磷)大都朝向复层植被区之趋势。典型相关分析结果,地表覆盖度与入侵植物数量两变量主要系透过第一个典型因素与第二个典型因素而影响到复层植被区之pH值、有机质等土壤理化性质。     

基于放射源理论的区域生态系统评价方法

研究区域生态系统定量评价方法对区域生态系统的建设与保护具有十分重要的意义。从放射源理论出发,首次将生态影响距离、生态源及生态影响效应的概念引入分析评价中,提出了区域生态系统的定量评价方法,并建立了基于景观空间格局的区域生态系统生态影响的定量计算公式。甘垛镇新庄片和横泾镇沿荡片的应用实例表明,该方法原理简明、结果直观,为区域生态系统的科学评价提供了定量评价方法。     

Mating system and individual reproductive success of sympatric anadromous and resident brook charr, <Emphasis Type="Italic">Salvelinus fontinalis</Emphasis>, under natural conditions

Salmonids are known for the occurrence in sympatry of two life-history forms, one that undergoes migration to sea before returning to freshwater to reproduce (anadromous) and one that inhabits freshwater without a migration phase (resident). Whereas one breeding population is often suggested by population genetic studies, mating patterns have rarely been directly assessed, especially when both sexes are found within each life-history form. By using highly polymorphic microsatellite loci and parentage analysis in a natural population of sympatric anadromous and resident brook charr (Salvelinus fontinalis), we found that gene flow occurred between the two forms and was mediated by resident males mating with both resident and anadromous females. Determinants of reproductive success, estimated by the number of surviving juveniles (ages 1 and 2 years), differed between the sexes. No strong evidence of the influence of size on individual reproductive success was found for males, whereas larger females (and hence most likely to be anadromous) were more successful. The higher individual reproductive success of anadromous fish compared to residents was mainly explained by this higher reproductive success of anadromous females. We suggest that resident males adopt a “sneaking” reproductive tactic as a way of increasing their reproductive success by mating with females of all sizes in all habitats. The persistence of the resident tactic among females may be linked to their advantage in accessing spatially constrained spawning areas in small tributary streams unavailable to larger females.     

Shifts in the spatio-temporal growth dynamics of shortleaf pine

Previous studies focusing on the growth history of Pinus echinata at the edge of its geographical range have suggested that changes in growth correspond to climatic and non-climatic (e.g., anthropogenic) factors. We employ a regime-dependent state-space model that allows us to detect and characterize the changes in tree growth dynamics over space and time using readily available dendrochronological and climatic data in the presence of various sources of uncertainty. We utilize methods common in atmospheric sciences but relatively unknown in ecology and forestry to develop a hierarchical model for tree growth and describe the growth dynamics. The utility of such methods for addressing ecological problems will grow as more high dimensional spatio-temporal processes are considered and datasets become more readily available.     

Roads and Landscape Pattern in Northern Wisconsin Based on a Comparison of Four Road Data Sources

Abstract:  Roads are important components of landscapes; they fragment habitat, facilitate invasive species spread, alter hydrology, and influence patterns of land use. Previous research on the ecological impacts of roads may have underestimated their effect because currently available sources of road data do not include the full road network. We compared differences in road density and landscape pattern among U.S. Census Bureau TIGER line files, U.S. Geological Survey 1:100,000-scale digital line graphs, and U.S. Geological Survey 1:24,000-scale digital raster graphics in northern Wisconsin to road data derived from 1:40,000-scale digital orthophotos. Road density measured from digital orthophotos (2.82 km/km²) was significantly greater than that of digital raster graphics (1.62 km/km²) and more than double that of digital line graphs (1.21 km/km²) and TIGER (1.27 km/km²) data. The increased road densities in raster graphics and orthophoto data were mainly due to the addition of minor roads. When all roads were used to define patch boundaries, landscape metrics produced with orthophoto data showed significantly greater levels of fragmentation than those based on line or raster graphics. For example, maximum patch size was 1074 ha and total edge was 109 km for line graphs, compared with 686 ha and 211 km for orthophoto data. Roads are missing in commonly used data, primarily because mapping standards systematically exclude minor roads. These standards are not ecologically based and may result in false assumptions about the ecological effects of roads. We recommend that future studies take special consideration of the completeness of road data and consider whether all ecologically relevant roads are included.     

苏北里下河地区湿地资源可持续利用的思考

以里下河地区湿地资源利用为例 ,剖析湿地资源开发过程中带来的相关环境问题 ,包括 :湿地面积缩小 ,自然灾害濒发 ;区内环境状况日趋恶化 ,生产与生活性污染严重 ;湿地功能日益衰退 ;湿地农业生产效益下降 ,农民的生产投入明显不足。此外 ,还探讨湿地生态系统可持续利用对策 ,具体有 :建立湿地可持续利用新的评价指标与标准 ,建立预警分析系统 ,以现代湿地生态工程技术为指导 ,全面提高湿地利用的社会、经济、环境综合效益     

土壤渗滤法治理湿地水环境污染

根据扎龙自然保护区独特的地理、地质条件，研究采用土壤渗滤法处理排入湿地的造纸废水，并从技术和实践分析的角度对该地浅表部亚粘土渗滤的稳定性及可行性进行了探讨。结果表明：保护区地表层的亚粘土对造纸废水中各项污染物均有较好的去除效果，其CODCr、BOD5、Cr^6 、NH4^ -N及TP的去除率分别达到了70％、84％、90％、78％及80％以上，在该处利用缓坡土地渗滤处理系统是稳定可行的。     

山东赤松种群的空间分布型及强度

利用分布类型和聚集强度指数对山东主产区赤松种群的空间分布型及强度进行了初步研究,结果表明：鲁东丘陵区的赤松种群生林一般表现为负二项分布和奈曼分布,鲁中南山地丘陵区的人工林则呈现均匀分布;在赤松种群不同发育阶段,出现了由幼苗→幼树→大中树扩散态势的一般规律,但鲁东丘陵区次生林由于受人为、虫害等因素的影响,其分布类型和聚散态势呈明显的多样化,鲁中南山地丘陵区人工林则表现为聚集→扩散的独特态势。     

秋色叶树种在园林造景中的应用

秋色叶树种是园林造景中重要的观赏树种之一，我国秋色叶树木资源十分丰富，开发利用秋色叶树木资源对我国园林建设具有重要意义．作者分析了秋色叶树种内涵，主要树种的性状、特征、观赏价值及在我国自然秋色景观中的应用等，初步探讨了它们在城市园林造景中应用方式、应用前景，提出了秋色叶树种选择应用的原则及应注意的问题．