Subjects: Geosciences >> Geography submitted time 2024-06-12 Cooperative journals: 《干旱区研究》
LEI Feiya
LI Xiaoshuang
TAO Ye
YIN Benfeng
RONG Xiaoying
ZHANG Jing
LU Yongxing
GUO Xing
ZHOU Xiaobing
ZHANG Yuanming。
Abstract： Biological soil crusts (BSCs) are the main active groundcover community in arid regions. BSCs can significantly affect the material cycle and energy exchange, improve the physical, chemical, and biological properties of surface soil, and influence the soil multifunctionality (SMF). Moss crust is an important type of BSCs. This study investigates the SMF variability of moss crust-covered and bare sand in the deserts of northwestern arid regions, and explored the main drivers of the variability. We analyzed eight crucial ecosystem function indicators. SMF was calculated by applying the mean method and factor analysis approach. We used the ordinary least square and structural equation modeling to explore the drivers of SMF changes. The results show that: (1) soil monofunctionality and SMF under moss crust cover were higher than those in bare sand (P<0.05). (2) The drivers of the SMF change in bare sand and under moss crust cover were very different. The main drivers of SMF in bare sand were aridity and soil water content, whereas the driver of SMF under moss crust cover was soil sand content(Sand). (3) The mean annual temperature had the largest indirect effect on changes in SMF for both soil in bare sand and under moss crust cover. Therefore, the development of moss crust significantly increased SMF and, in addition, modulated the relevant drivers of SMF. Our results are important for a deep understanding of the differences and drivers of SMF in desert soil with bare sand and under moss crust cover
Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： Xylem structure traits are the basis for plant adaptation to different water conditions and are core planttraits in response to changes in environmental conditions. The typical shrubs Reaumuria soongarica andCalligonum mongolicum in the northwest desert region were selected as the subjects for comparison betweenstem xylem structure and functional traits to understand the differences or similarities of different species in thesame habitat and the xylem structure plasticity of the same species under different environmental conditions. Theresults showed that (1) Xylem structure traits of R. soongarica and C. mongolicum were significantly different.The mean vessel diameter and vulnerability index of C. mongolicum were significantly higher than those of R.soongarica, whereas the opposite was true for vessel density and vessel grouping index. (2) The patterns ofxylem structure traits in response to climate change differed between R. soongarica and C. mongolicum. Themean vessel diameter and vessel thickness-to-span ratio of C. mongolicum significantly reduced with increasingmean annual precipitation and aridity index, whereas that of R. soongarica were unrelated, and only thetheoretical hydraulic conductivity had a significant positive correlation with the mean annual precipitation andaridity index. (3) There was a trade-off between efficiency and safety in the xylem hydraulic conductivity systemof R. soongarica, whereas none was observed in C. mongolicum. (4) The trait network analysis results indicatedthat the central traits of both R. soongarica and C. mongolicum were mean vessel diameters. Changes in meanvessel diameter mediate changes in the trait network. Xylem structure traits between R. soongarica and C.mongolicum were significantly different, with R. soongarica having a more conservative water use strategy thanC. mongolicum.
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