【目的】对香山公园典型植被生态环境效应相关影响因子分析评价,以期为游客选择香山公园最佳游览时间及公园绿地管理和景观设置提供理论依据。【方法】夏季连续10天在北京香山公园5处不同植物类型的游憩点进行测定,选择园外广场为对照,分析6处监测点微气候、PM_(10)和PM_(2.5)浓度、人体舒适度、空气负离子浓度及噪音情况,研究各因子日变化规律,并统计比较不同游憩点间差异和各生态因子间的相关性。【结果】香山公园日空气温度和空气相对湿度呈单峰型变化,平均降低空气温度1.7℃,增加空气相对湿度6%;人体舒适度达到Ⅱ级标准的时间最长可达8.5 h;PM_(10)和PM_(2.5)浓度均呈早晚高、午后低的双峰型变化特征,各游憩点对PM_(2.5)日均净化率达27.6%,对PM_(10)日均净化率达25.9%,2种颗粒物浓度间呈极显著正相关(P<0.01),2种颗粒物浓度与温度、湿度分别呈显著负相关(P<0.05)和极显著正相关(P<0.01);负离子浓度呈波峰波谷交替变化,早、中、晚出现3个高峰,园内日均值为795个·cm^(-3),为园外的2.43倍,与PM_(10)和PM_(2.5)浓度极显著负相关(P<0.01),与温度显著负相关(P<0.05)、与湿度极显著正相关(P<0.01),通过空气离子评价指数得出各游憩点均在6:00前后和20:00—21:00达到了轻度或中度污染;噪音呈现出早晚2个高峰,园内噪音平均值为40.3 d B,平均降噪率达21.8%,与植物郁闭度显著负相关(P<0.05);植物郁闭度与负离子浓度极显著正相关(P<0.01),与PM_(10)和PM_(2.5)质量浓度极显著负相关(P<0.01)。【结论】香山公园绿地内不同植被类型间增湿、降温、抗污染、降噪等能力存在差别,黄栌混交林的生态效应最高,草坪最低;香山公园夏季合理的游憩时段为7:00—11:00和17:00—20:00。
Eight Juglans populations (4 populations of J. sigillata and 4 of J. regia), which are distributed in Yunnan, Sichuan, Henan, and Shanxi Province, were selected to investigate their genetic structure and diversity usi...
详细信息
Eight Juglans populations (4 populations of J. sigillata and 4 of J. regia), which are distributed in Yunnan, Sichuan, Henan, and Shanxi Province, were selected to investigate their genetic structure and diversity using 8 microsatellite loci. A moderate level of genetic diversity was observed at population level by the total 71 of alleles. The mean expected heterozygosity (H_e) of all populations was 0.618. The proportion of genetic differentiation among populations accounted for 19.6% of the whole diversity, and the gene flow between populations (N_m) was 1.02. The result of UPGMA clustering indicated that the populations were congregated according to their geographic distances instead of tree species.
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