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21.
Frauke Ecke Pernilla Christensen Per Sandström Birger Hörnfeldt 《Landscape Ecology》2006,21(4):485-497
Several studies indicate a long-term decline in numbers of different species of voles in northern Fennoscandia. In boreal Sweden, the long-term decline is most pronounced in the grey-sided vole (Clethrionomys rufocanus). Altered forest landscape structure has been suggested as a possible cause of the decline. However, habitat responses of grey-sided voles at the landscape scale have never been studied. We analyzed such responses of this species in lowland forests in Västerbotten, northern Sweden. Cumulated spring densities representing 22 local time series from 1980–1999 were obtained by a landscape sampling design and were related to the surrounding landscape structure of 2.5×2.5 km plots centred on each of the 22 1-ha trapping plots. In accordance with general knowledge on local habitat preferences of grey-sided voles, our study supported the importance of habitat variables such as boulder fields and old-growth pine forest at the landscape scale. Densities were negatively related to clear cuts. Habitat associations were primarily those of landscape structure related to habitat fragmentation, distance between habitat patches and patch interspersion rather than habitat patch type quantity. Local densities of the grey-sided vole were positively and exponentially correlated with spatial contiguity (measured with the fragmentation index) of old-growth pine forest, indicating critical forest fragmentation thresholds. Our results indicate that altered land use might be involved in the long-term decline of the grey-sided vole in managed forest areas of Fennoscandia. We propose two further approaches to reveal and test responses of this species to changes in landscape structure. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(3-4):363-375
Abstract The study of plant diversity and its role in ecosystem functioning is becoming a central issue in ecology. The relationships between carbon storage and tree diversity of natural forest at small scale are still unclear. This research investigated these relationships in an old‐growth forest at Changbai Mountain, Northeast China. It was found that at small scale, tree carbon storage generally increases with increasing tree species richness, but for stands with same species richness, tree carbon storage varies dramatically. At the small scale, tree species evenness has a significantly linear relationship with nature logarithm of total tree carbon storage. The stand carbon storage of trees is mainly controlled by stand tree composition. Fraxinus mandshurica, Pinus koraiensis, Quercus mongolica, Tilia amurensis, and Acer mono contribute more than 85% of stand carbon storage of trees. Stands with similar tree composition at small scale have different soil organic carbon storage and nutrient contents. Tree species evenness has great impact on soil N content at the soil horizon less than 30 cm deep, but its impacts on C/N, P, K, and S contents are small. Tree density has a negative linear relationship with soil organic C and C∶N ratio at the soil horizon is less than 30 cm deep. The implication of our findings here for carbon sequestration in the Kyoto Protocol is also discussed. 相似文献
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The soil CO2 evolution rate was measured in a virgin Korean pine forest. The results in June showed that the lowest value of evolution
rate was 220 mg/(m2·h) and appeared at 6:00 a.m. The highest value was 460 mg/(m2·h) at 18:00. The rates of CO2 evolution were related with soil temperature. On the basis of the constructed regression equation and the monthly average
values of temperature, the magnitude of CO2 evolution from Korean pine forest soil was 10.4 t/hm2 during a growing season.
This project was funded by the Opened Research Station of Changbai Mountain Forest Ecosystem, Chinese Academy of Sciences.
Responsible editor: Zhu Hong 相似文献
26.
透光抚育对红松阔叶林群落结构与生产力的影响 总被引:1,自引:0,他引:1
采用样带网格调查方法和群落重要值分析方法,研究透光抚育(全透光、半透光、未透光)对红松阔叶混交林群落(人天混群落)的树种组成结构、径级分布、蓄积量和红松蓄积生产力的影响效果。结果表明:沿由小到大的透光强度,人天混群落中红松重要值依次增大(0.499~1.000),透光有利于人天混群落中红松优势地位增强;红松大径木比例依次增加(0.00%~54.0%),小径木比例依次减少(74.9%~2.7%),透光有利于人天混群落中红松大径木比例提高;群落蓄积量依次增加(60.2475~230.4051m^3/hm^2),红松蓄积生产力依次增加(1.2692~5.3603m^3/hm^2·a),透光有利于人天混群落蓄积量及红松蓄积生产力的提高。 相似文献
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本项研究在总结传统育苗的基础上,应用推广了苗木生长调控新技术,新老技术紧密结合配套使用,取得了松树大田育苗的良好效果。通过选择圃地、控制播种量、精耕细作、科学管理,并在苗木旺盛生长期的8月中旬进行切根、剪顶,有效地促进了苗木生长发育。结果表明,马尾松播种量45kg/hm2,培育苗木169.2万株,Ⅰ、Ⅱ、Ⅲ级合格苗出圊率时%,其中优质苗率达53.5%。苗木茎干粗壮、根系发达、菌根丰富,达到了大田优质苗的质量标准。 相似文献
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精制马尾松花粉的营养和加工储藏技术 总被引:8,自引:0,他引:8
本文对马尾松花粉合理适时采摘,及时在常温35℃以下进行干燥,使含水量迅速下降为10%以下,经紫外线处理1~2小时达到灭菌控菌。经过加工处理的马尾松花粉,使之能储藏1~3年质量不变,与冰箱0~5℃储藏质量一样好。松花粉营养丰富,蛋白质含量较高,Fe、P、Mn、Ca、Zn含量多,Mg更为丰富,多种的营养成分,对人体健康有利,能促使体内元素平衡.马尾松花粉又是民间食疗珍品和传统中药材,因此,对加快开发马尾松花粉是有重大意义的。 相似文献
30.
马尾松净光合速率初步研究 总被引:4,自引:0,他引:4
本文研究了马尾松一年生苗的鳞叶及幼树1、2年生针叶的月龄与净光合速率的变化规律;马尾松天然更新树团的生境,生产结构,净光合速率及净生产力的变化。进一步论述了马尾松的光合生态特性,并据此对马尾松育苗,培育过程中抚育管理措施制订及实施的最佳时段进行了论证。 相似文献