地形因子对FAST周边喀斯特植物多样性及空间分布的影响

Influence of topographic factors on plant diversity and spatial distribution of karst around FAST

关键词:  喀斯特峰丛洼地, 地形因子, 物种多样性, 空间分布, FAST

Key words:  karst peak-cluster depression, topographical factor, species diversity, spatial distribution, FAST

摘要:

为探究地形因子对500米口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)周边植物物种多样性及空间分布的影响,该文选取FAST周边喀斯特峰丛洼地3种典型植物群落(乔木层、灌木层、藤本层)作为研究对象,采用方差分析及典范对应分析(CCA)研究不同地形因子(海拔、坡度、坡向、坡位)梯度下植物群落物种多样性及空间分布特征。结果表明:(1)FAST周边植物群落α多样性指数呈现灌木层>乔木层>藤本层的趋势,乔木层、藤本层植物α多样性指数随海拔升高而增加(P<0.05),地形因子对灌木层植物α多样性无显著性影响。(2)FAST周边植物群落物种的空间分布受海拔的影响最大,其次为坡度(P<0.05)。(3)FAST周边3种植物群落的Jaccard相似性指数随海拔的升高呈现增加的趋势,沿坡度的增加呈现先升高后降低的趋势。综上所述,物种对生境的选择具有差异性,海拔和坡度是影响FAST周边喀斯特峰丛洼地植物群落空间分布的关键因子。

Abstract:

To explore the influence of topographic factors on the diversity and spatial distribution of plant species around FAST(Five-hundred-meter Aperture Spherical radio Telescope), three typical plant communities(tree layer, shrub layer, vine layer)in the karst peak-cluster depression around FAST were selected as the study objects, and ANOVA and canonical correspondence analysis(CCA)were used to investigate the species diversity and spatial distribution of plant communities under different topographic factors(altitude, slope, aspect, and gradient). The results were as follows:(1)The α-diversity index of plant communities around FAST showed a trend of shrub layer > tree layer > vine layer, and the α-diversity index of plants in the tree layer and vine layer increased with the increase of altitude(P<0.05), while the topographic factor had no significant effect on the α-diversity of plants in shrub layer.(2)The spatial distribution of plant community species around FAST was most influenced by the altitude, followed by the slope(P<0.05).(3)The Jaccard similarity index above 70% was extremely dissimilar and moderately dissimilar at altitude and slope gradients. The Jaccard similarity index of the three plant communities tended to increase with the increase of altitude and then decrease along the increase of the slope around FAST. In summary, species differed in their habitat selection, and altitude and slope are key factors affecting the spatial distribution of plant communities in the karst depressions around FAST. Species diversity can better reflect the differences in plant communities in terms of species composition. Species diversity is not only influenced by topographic factors, but also related to biotic and abiotic factors, such as temperature, precipitation, human activities, and functional plant traits. Therefore, corresponding environmental factors need to be added in future studies to further investigate the intrinsic mechanisms of plant species diversity and species spatial distribution at the regional scale and to strengthen the ecological protection of the surrounding area, improve the forest composition, and provide a good natural environment around FAST and in the karst peak-cluster depression.