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首页> 外文学位 >The influence of urbanization on structure and function of riparian forest fragments in New Haven County, Connecticut.
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The influence of urbanization on structure and function of riparian forest fragments in New Haven County, Connecticut.

机译：城市化对康涅狄格州纽黑文县河岸森林碎片的结构和功能的影响。

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Buffer zones (200m on either side) along 18 low-order streams in New Haven County, Connecticut were surveyed in order to detect influences of urbanization on ecosystems. Plant species abundances were recorded and soil samples evaluated for bulk density and percent carbon and nitrogen. Anthropogenic disturbance was quantified by percent impervious surface (IS) coverage within five specified radii of each site and by distance to the nearest road. At each site, impervious surface coverage within a 100m radius was very highly correlated with %IS within 500m, and fairly well correlated with 50m and 75m radii. Distance to nearest road and %IS were uncorrelated. Plant species were observed to occur within ranges of environmental factors commensurate with their known successional status and degree of invasiveness or, conversely, sensitivity. Sensitive, forest-interior species were found at sites with %IS 8, distance to road >80m, soil bulk density 0.6 g/cm3, % non-native species 10, and % soil carbon and nitrogen > 6. Ruderal and invasive species were mostly found at sites with % IS > 14, distance to road 60m, soil bulk density > 0.7 gm/cm3, % non-native species > 20, and % soil carbon and nitrogen 3. Generalists were found at intermediate values. In soils, percent carbon, percent nitrogen, and bulk density were highly correlated. Elevation, distance to nearest road, soil carbon, soil nitrogen, bulk density, litter depth, and total tree basal area were correlated with the upper limit of proportion of non-native species, following the ceiling-factor distribution model; e.g., low proportions of non-native species were observed at all elevations but high proportions of non-native species were observed only at relatively high elevations. The consequence of this finding is that while a high proportion of non-native species serves as an indicator of other types of ecosystem degradation, a low proportion of non-native species does not in itself indicate, or 'guarantee' ecosystem integrity as defined by various other characteristics. Results also quantified the distinctions among forested patches classified into different cover types by remote sensing.
机译：为了检测城市化对生态系统的影响，对康涅狄格州纽黑文县沿18条低序河流的缓冲区（两侧各200m）进行了调查。记录植物物种的丰度，并评估土壤样品的堆积密度以及碳和氮百分比。人为干扰通过每个站点的五个指定半径内的不透水表面（IS）覆盖率百分比以及与最近道路的距离来量化。在每个站点，半径为100m的不透水表面覆盖率与500m内的％IS高度相关，并且与半径为50m和75m的高度相关。到最近道路的距离与％IS不相关。观察到植物物种在与其已知演替状态和入侵程度或相反的敏感性相称的环境因素范围内发生。在％IS <8，距道路的距离> 80m，土壤容重<0.6 g / cm3，非本地物种的百分比<10和土壤碳和氮的百分比> 6的地点发现了敏感的森林内部物种。入侵物种多见于以下地区：％IS> 14，距道路的距离<60m，土壤容重> 0.7 gm / cm3，％非本地物种> 20，％土壤碳和氮<3。价值观。在土壤中，碳百分比，氮百分比和堆积密度高度相关。根据最高限度因子分布模型，海拔，到最近道路的距离，土壤碳，土壤氮，容重，枯枝落叶深度和总树基面积与非本地物种比例的上限相关。例如，在所有海拔高度都观察到低比例的非本地物种，但仅在相对较高的海拔高度才观察到高比例的非本地物种。这一发现的结果是，虽然高比例的非本地物种可以作为其他类型的生态系统退化的指标，但低比例的非本地物种本身并不能表明或“保证”了生态系统的完整性各种其他特征。结果还量化了通过遥感分类为不同覆盖类型的森林斑块之间的区别。

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