Wang Yan-Feng, Xiao Bo, Wang Wan-Fu, Yu Xing-Xing, Zhang Xue
Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Ying Yong Sheng Tai Xue Bao. 2022 Jul;33(7):1729-1737. doi: 10.13287/j.1001-9332.202207.004.
Microhabitat factors play an important role in regulating bryophyte species distribution and the development of bryophyte-dominated biological soil crusts (hereafter bryophyte crusts). We investigated the distribution and development of bryophytes in eight microhabitats in the water-wind erosion crisscross region of the Loess Pla-teau. We used the line intercept transects to explore and quantify the influencing pathways of microhabitat factors on bryophyte diversity and analyzed the influencing pathways of plant cover, slope aspect, and slope gradient by using structural equation model to quantify influencing coefficients. Our results showed that: 1) The Patrick, Shannon, Pielou, and Simpson indcies of bryophytes under plant canopy were 63.4%, 66.6%, 91.0%, and 68.3% lower than that without plant canopy, respectively, while the thickness, biomass, and chlorophyll content of bryophyte crusts were 0.5, 0.2, and 1.3 times higher than that without plant canopy, respectively. 2) The Patrick, Shannon, Pielou, and Simpson indexes of bryophytes on the north slope were 0.6, 0.9, 5.6, and 0.9 times higher than those on the south slope, while the thickness, biomass, and chlorophyll content of bryophyte crusts were 0.3, 0.3, and 0.6 times higher than those on the south slope, respectively. 3) As the slope increasing from 14° to 34°, the Patrick, Shannon, Pielou, and Simpson indexes of bryophyte were decreased by 59.8%, 84.1%, 57.3% and 68.0%, and the thickness, biomass, and chlorophyll content of bryophyte crusts were decreased by 15.2%, 25.0%, and 16.5%, respectively. 4) The importance of the three microhabitat factors on bryophyte diversity and the development of bryophyte crusts followed an order of plant canopy cover > slope aspect > slope gradient. The primary influencing pathway varied among the microhabitat factors. In conclusion, plant cover, slope aspect, and slope gradient significantly affected the distribution of bryophytes species and developmental level of bryophyte crusts through direct and indirect pathways. Therefore, full consideration should be given to microhabitat conditions when using bryophyte crusts to control desertification.
微生境因素在调节苔藓植物物种分布以及苔藓植物主导的生物土壤结皮（以下简称苔藓结皮）的发育过程中发挥着重要作用。我们对黄土高原水蚀风蚀交错区8种微生境中苔藓植物的分布与发育情况进行了调查。我们采用样线截距法来探究并量化微生境因素对苔藓植物多样性的影响途径，并运用结构方程模型对植被盖度、坡向和坡度的影响途径进行分析，以量化影响系数。我们的研究结果表明：1）有植被覆盖下苔藓植物的帕特里克指数、香农指数、皮洛指数和辛普森指数分别比无植被覆盖下低63.4%、66.6%、91.0%和68.3%，而苔藓结皮的厚度、生物量和叶绿素含量分别比无植被覆盖下高0.5倍、0.2倍和1.3倍。2）北坡苔藓植物的帕特里克指数、香农指数、皮洛指数和辛普森指数分别比南坡高0.6倍、0.9倍、5.6倍和0.9倍，而苔藓结皮的厚度、生物量和叶绿素含量分别比南坡高0.3倍、0.3倍和0.6倍。3）随着坡度从14°增加到34°，苔藓植物的帕特里克指数、香农指数、皮洛指数和辛普森指数分别下降了59.8%、84.1%、57.3%和68.0%，苔藓结皮的厚度、生物量和叶绿素含量分别下降了15.2%、25.0%和16.5%。4）这三种微生境因素对苔藓植物多样性和苔藓结皮发育的重要性排序为：植被盖度＞坡向＞坡度。主要影响途径因微生境因素而异。总之，植被盖度、坡向和坡度通过直接和间接途径显著影响了苔藓植物物种的分布以及苔藓结皮的发育水平。因此，在利用苔藓结皮治理荒漠化时，应充分考虑微生境条件。
