Browsing by Author "Xin, Zhiming"

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    Mesophytic and less-disturbed mountainous habitats are important for in situ conservation of rare and endangered plants
    (Elsevier, 2023-08) Zhou, Quanlai; Li, Xuefeng; Wang, Yongcui; Xin, Zhiming; Musa, Ala; Wang, Lixin; Earth and Environmental Sciences, School of Science
    Protecting rare and endangered plants is important for maintaining ecosystem structure and function, conserving biodiversity, and even sustaining national economic growth. However, the effects of habitat characteristics, geographical distribution, and climatic factors on the distribution of rare and endangered plants in China, home to 19.4 % of the world’s endangered species, remain unclear. To address this important knowledge gap, we collected information on climate, altitude, habitat, and distribution of rare and endangered plants in China to determine their habitat characteristics, geographical distribution, and the relationships between environmental factors and species density. We found that rare and endangered plants tend to occur in warm, humid, and forested habitats. Mountains, rather than plains, hills, eolian landforms, tablelands, lakes, and glaciers, can provide mesophytic and less-disturbed refuges for rare and endangered plants. In particular, medium and medium high-altitude mountains located in monsoon dominated regions with high precipitation, temperature, and humidity provide habitats for species of rare and endangered plants with high density. Our findings highlight the importance for a more explicit consideration of these mountains for in situ conservation of rare and endangered plants.
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    Relationship between seed morphological traits and wind dispersal trajectory
    (CSIRO, 2019) Zhou, Quanlai; Liu, Zhimin; Xin, Zhiming; Daryanto, Stefani; Wang, Lixin; Qian, Jianqiang; Wang, Yongcui; Liang, Wei; Qin, Xuanping; Zhao, Yingming; Li, Xinle; Cui, Xue; Liu, Minghu; Earth Sciences, School of Science
    The structure and dynamics of plant populations and communities are largely influenced by seed dispersal. How the wind dispersal trajectory of seeds shifts with differences in seed morphology remains unknown. We used a wind tunnel and video camera to track the dispersal trajectory of seven species of Calligonum whose seeds have different kinds of appendages and other morphological traits, using variable wind speeds and release heights to determine the relationship between seed morphological traits and wind dispersal trajectory. Concave-, straight-line-, horizontal-projectile- and projectile-shaped trajectories were found. Dispersal trajectories such as the horizontal projectile (HP) and projectile (P) tended to have a long dispersal distance. Straight line (SL) and concave curve (CC) trajectories tended to have a short dispersal distance. Seeds with bristles and large mass tended to have SL and CC trajectories, those with wings or balloon and small mass tended to have HP and P trajectories. Wind speed tended to have a stronger influence on the dispersal trajectory of light and low-wing-loading seeds, and release height tended to have a stronger influence on the dispersal trajectory of heavy and high-wing-loading seeds. Thus, seed wind dispersal trajectory is not only determined by seed morphological characteristics but also by environmental factors such as wind speed and release height.
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    Responses of secondary wind dispersal to environmental characteristics and diaspore morphology of seven Calligonum species
    (Wiley, 2019) Zhou, Quanlai; Liu, Zhimin; Xin, Zhiming; Daryanto, Stefani; Wang, Lixin; Xuehua, Li; Wang, Yongcui; Liang, Wei; Qin, Xuanping; Zhao, Yingming; Li, Xinle; Cui, Xue; Liu, Minghu; Earth Sciences, School of Science
    Secondary diaspore dispersal by wind, that is, wind‐driven movement along the ground surface (GS), is important for the structure and dynamics of plant populations and communities. However, how wind velocity (WV), GS, and diaspore morphology influence diaspore secondary dispersal by wind are unclear. We used a wind tunnel and video camera to measure the threshold of WV (TWV) and diaspore velocities (DV) of secondary diaspore dispersal. Diaspores of seven Calligonum species with different appendages (wings, bristles, membranous balloon, and wings + thorns) were used to determine the TWV and DV under variable wind speed (4, 6, 8, and 10 m s‐1) and four GSs (cement, sand, loam, and gravel). GS and diaspore morphological traits explained 37.1 and 18% of diaspore TWV, respectively. Meanwhile, WV, GS, and diaspore morphological traits explained 62.4, 13.6, and 3.2% of DV, respectively. An increasing trend was shown for TWV, and a decreasing trend was shown for DV in the order of cement, sand, loam, and gravel surfaces. Spherical and light diaspores had low TWV and high DV, whereas winged and heavy diaspores had high TWV and low DV. Our results indicated that adaptive features of diaspore appendages might be the result of selection for primary dispersal or secondary dispersal. The mechanism of diaspore secondary dispersal is important for understanding the recovery of degraded sand dunes and providing theoretical support for restoration practices.
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    Scale effect of climate factors on soil organic carbon stock in natural grasslands of northern China
    (Elsevier, 2023-02) Liu, Zhimin; Zhou, Quanlai; Ma, Qun; Kuang, Wennong; Daryanto, Stefani; Wang, Lixin; Wu, Jing; Liu, Bo; Zhu, Jinlei; Cao, Chengyou; Li, Xuehua; Kou, Zhenwu; Shou, Wenkai; Qian, Jianqiang; Liu, Minghu; Xin, Zhiming; Cui, Xue; Liang, Wei; Earth and Environmental Sciences, School of Science
    Changes in grassland soil organic carbon stock (SOCS) may significantly affect the regional climate and carbon cycle of terrestrial ecosystems. However, how the impact of climate factors on SOCS and the dominant climate factors are regulated by the area scale of grasslands remains unclear. To understand the scale effects of climate on SOCS and how to accurately estimate SOCS at different scales, three area scales were defined by extending grassland types on the basis of meadow, typical and desert grasslands (Scale I (average area 37.22 × 104 km2) included each of these three types of grasslands, Scale II (average area 74.45 × 104 km2) was achieved by a pairwise combination of these three types of grasslands. Scale III (area 111.67 × 104 km2) was an aggregate of these three types of grasslands), the relationship between climate factors (i.e., mean annual precipitation, mean annual temperature, annual maximum temperature, annual minimum temperature, mean annual ground temperature, mean annual humidity, annual sunshine duration, annual maximum depth of accumulated snow, and the number of snow-covered days) and SOCS at the three scales were explored in the grasslands of northern China. Our results indicated that the total SOCS in grasslands at the three scales was ordered as desert grassland < meadow grassland < typical grassland. Of the nine climate factors, mean annual precipitation, positively correlated with SOCS, was the most significant climatic factor for all three scales. The dominant climatic factors of the SOCS differed across grassland area scales (i.e., MAP and MAH for meadow grassland, AMAT, MAP, NSD, and MAH for typical grassland, MAP, NSD, MAH, AMAT, and ASD for meadow-typical grassland scale, MAP, MAT, and MAGT for typical-desert grassland scale, MAP and MAT for meadow-typical-desert grassland scale). The impact of climate factors on the SOCS decreased as the scale increased. It is essential to screen appropriate climate predictors according to a given area scale when assessing regional SOCS. Multiple climate factors are better predictors for accessing SOCS at a small scale. At a large scale, however, dominant climatic factors are predictors that are more efficient.
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    Soil phosphorus budget in global grasslands and implications for management
    (Elsevier, 2017-09) Zhou, Quanlai; Daryanto, Stefani; Xin, Zhiming; Liu, Zhimin; Liu, Minghu; Cui, Xue; Wang, Lixin; Earth Science, School of Science
    Grasslands, accounting for one third of the world terrestrial land surface, are important in determining phosphorus (P) cycle at a global scale. Understanding the impacts of management on P inputs and outputs in grassland ecosystem is crucial for environmental management since a large amount of P is transported through rivers and groundwater and detained by the sea reservoir every year. To better understand P cycle in global grasslands, we mapped the distribution of different grassland types around the world and calculated the corresponding P inputs and outputs for each grassland type using data from literature. The distribution map of P input and output revealed a non-equilibrium condition in many grassland ecosystems, with: (i) a greater extent of input than output in most managed grasslands, but (ii) a more balanced amount between input and output in the majority of natural grasslands. Based on the mass balance between P input and output, we developed a framework to achieve sustainable P management in grasslands and discussed the measures targeting a more balanced P budget. Greater challenge is usually found in heavily-managed than natural grasslands to establish the optimum amount of P for grass and livestock production while minimizing the adverse impacts on surface waters. This study provided a comprehensive assessment of P budget in global grasslands and such information will be critical in determining the appropriate P management measures for various grassland types across the globe.
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    The Adaptive Capacity of Alien and Rare Species in China
    (MDPI, 2022-11-27) Zhou, Quanlai; Xin, Zhiming; Wang, Yongcui; Miao, Renhui; Liu, Zhimin; Zong, Lu; Li, Xuehua; Ma, Qun; Liang, Wei; Yu, Haibin; Wang, Lixin; Earth and Environmental Sciences, School of Science
    Alien and rare plants tend to adapt to contrasting biotic and abiotic conditions. However, adaptability assessments of alien and rare plants using biological and habitat characteristics in stressful and disturbed environments are limited. We collected and demonstrated the biological and habitat characteristics and assessed the adaptive capacity of alien and rare plants in China using the analytic hierarchy process. Biological characteristics, such as dispersal strategy, sexual and asexual reproduction modes, life form, and habitat characteristics (e.g., habitat type and distribution spatial extent), are important indicators of the adaptability of alien and rare plants to stressful and disturbed environments. Alien plants have a higher adaptive capacity to disturbed environments than rare plants, while rare plants have a higher adaptive capacity to stressful environments than alien plants. Stressful and disturbed environments constrain the adaptive capacity of alien and rare plants, respectively. However, the constraint on alien plants from stressful environments is weaker than that on rare plants from disturbed environments. Understanding the adaptive capacity of alien and rare plants will help researchers and policymakers develop strategies for preventing the invasion of alien plants as well as protecting rare and endangered plants.