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升金湖洲滩植物群落沿高程变化特征及影响因素

Characteristics and influencing factors of plant community changes along elevational gradients in the marshland of Shengjin Lake

  • 摘要: 为了揭示升金湖洲滩植物随高程变化而变化的规律,以样线和样方相结合的方法,于2023年2月16—17日和4月15—16日,对升金湖洲滩沿高程梯度分布的植物群落进行了调查研究。研究结果表明,在升金湖洲滩共记录到26种草本植物,隶属于15科24属,菊科(Asteraceae)、禾本科(Poaceae)为优势科,陌上菅(Carex thunbergii)为优势种,一年生和二年生草本植物占比较高,达69.2%;高程区与中程区群落外貌相似,二者与低程区相差较大,陌上菅在2个时期3个区均是群落优势种,主要伴生种在不同区区别较大,不同时期也有差别;植物种类从适应长期淹水环境的植物逐渐过渡到适应短期淹水的植物,3个区共有的物种较少(2月、4月共有的物种分别为4种、2种),由2月至4月,低程区水淹的环境加重了对植物的生存考验,洲滩环境的异质性也加大,低程区和中程区共有的物种由10种降为6种;对于物种多样性,随着高程的升高,各区物种总数整体降低,且2月低程区与另2个区样方物种平均数差异显著(p<0.01),受环境异质性影响,多样性指数未与物种丰富度呈现完全一致的变化趋势,由2月至4月,低程区样方物种平均数、Shannon-Wiener多样性指数显著降低(p<0.05),而高程区变化不显著。水位变动是影响洲滩植物群落分布异质性和多样性格局的主导因素。

     

    Abstract: To reveal the distribution patterns of wetland plant communities across elevational gradients, a combined approach utilizing sampling lines and plots was employed to investigate the plant communities along these gradients in the Shengjin Lake marshland at different seasons. The results showed that the flora of the Shengjin Lake marshland comprised a total of 26 herbaceous plant species, belonging to 15 families and 24 genera, Asteraceae and Poaceae were the dominant families, with Carex thunbergia as the dominant species. Annual and biennial plants accounted for a relatively high proportion of 69.2%. The community structure in the high and middle elevations exhibited similarities, with a notable difference from the low elevation area. Carex thunbergii was the dominant species in all three elevations during both seasons. However, the main associated species differed significantly among the elevations, and there were also some differences across different seasons. Plant species gradually changed from species adapted to long-term flooding to species adapted to short-term flooding, there were few common species among the three areas, with only 4 common species in February and 2 in April. From February to April, the increased flooding in the low elevation area posed greater challenges for plant survival. Additionally, the heterogeneity of the intertidal environment intensified, resulting in the number of common species in the low and middle elevation areas, from 10 to 6. For species diversity, as the elevation gradient increased, the total species count in each area exhibited a general decreasing trend. Specifically, in February, there was a significant difference (p<0.01) in the average number of species between the low elevation area and the other two areas. Due to environmental heterogeneity, the other diversity indices did not consistently reflect a trend corresponding to changes in species richness. From February to April, the average number of species and Shannon index in the low elevation area sample plots decreased significantly (p<0.05), whereas the changes in the high elevation area were not significant. Based on the results, the factors influencing the characteristics of plant communities were analyzed and discussed, with water level fluctuations identified as the primary factor affecting the distribution heterogeneity and diversity of plant communities in the Shengjin Lake marshland.

     

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