新疆天山南坡中段种子植物区系垂直分布格局分析

对植物多样性垂直分布格局及其维持机制的研究可以有效揭示植物物种多样性分布特征及其环境影响因子。本文通过野外调查、查阅标本并结合相关文献资料,对天山南坡中段种子植物区系沿海拔梯度的分布格局进行了系统研究。结果显示,在大区域尺度上,科属种的物种丰富度随海拔升高均呈先增加后减少的趋势,且最高值出现在中低海拔1900~2000 m处;不同生活型植物沿海拔梯度的变化格局有所不同,其中,乔木、一年生草本、藤本及寄生植物表现出随海拔升高物种丰富度逐渐降低的趋势,灌木、多年生草本及二年生草本植物物种丰富度则呈先增加后减少的变化趋势;从植物区系地理成分来看,世界分布所占的比重沿海拔梯度升高呈先增加后减少的趋势;温带地理成分所占的比重沿海拔梯度升高呈缓慢上升趋势;古地中海地理成分所占的比重沿海拔梯度升高呈先增加后减少然后再增加的变化趋势;热带地理成分所占的比重沿海拔升高呈逐渐下降的趋势;东亚地理成分所占的比重沿海拔梯度升高呈先增加后减少然后再增加的变化趋势。对该分布格局与当地干旱的气候条件及海拔梯度上热量和水分条件的变化相适应。

Vertical distribution patterns of the seed plant flora in the middle section on the southern slopes of the Tianshan Mountains in Xinjiang,China

Studies on the vertical distribution pattern of plant diversity and its maintenance mechanism can effectively reveal the distribution characteristics of plant species diversity and its environmental impact factors. Furthermore, such studies can provide a theoretical basis for the sustainable development and utilization of species resource protection areas. Based on field investigations, reference plant specimens, and related literature data, the floristic characteristics of wild seed plants along altitudinal gradients and the environmental impact factors in the middle section of the southern slopes of the Tianshan Mountains in Xinjiang (China) were systematically analyzed. Results showed that species richness at the family, genus, and species levels first increased and then decreased at the regional scale. Specifically, species richness showed a unimodal distribution, with the peak observed at mid to low elevations ranging from 1900 to 2000 m. Different plants life-forms demonstrated different change patterns along the altitudinal gradient. Plant diversity, including that of trees, annual herbs, vines, and parasitic plants, decreased with the increase in altitude. The richness of shrubs, perennial herbs, and biennial herbs showed unimodal change patterns. From the perspective of the geographical composition of flora, the cosmopolitan geographical components showed a slow unimodal trend along the elevational gradient; the temperate geographical components increased slowly along the elevational gradient; the ancient Mediterranea geographical components (T_dzh) showed a double-peak change pattern along the altitudinal gradient; the tropical geographical components (T_rd) showed a gradual decreasing trend with the increase in elevation; and the overall distribution trend of the East Asian geographical components (T_dy) demonstrated a double-peak distribution pattern with the increase in altitudinal gradient. These distribution patterns are compatible with the local climatic conditions as well as the changes in heat and moisture along the elevational gradient.