[Assessment of the current invasive situation of alien plants in semi-arid area of Northeast China].

Alien invasive plants have been found in the semi-arid region of Northeast China for a long time, but the overall invasion situation is rarely reported. In this study, we established a database of alien invasive plants in the semi-arid area of Northeast China through field investigation, specimen collection, research of specimen online information platform and literature. The results showed that there were 34 species of alien invasive plants belonging to 26 genera and 10 families in the semi-arid area of Northeast China, among which the Composite family had the largest number of richness, with 9 genera (34.

Belowground bud banks and land use change: roles of vegetation and soil properties in mediating the composition of bud banks in different ecosystems.

Introduction: Belowground bud banks play integral roles in vegetation regeneration and ecological succession of plant communities; however, human-caused changes in land use severely threaten their resilience and regrowth. Although vegetation attributes and soil properties mediate such anthropogenic effects, their influence on bud bank size and composition and its regulatory mechanisms under land use change have not been explored.

Methods: We conducted a field investigation to examine impacts of land use change on bud bank size and composition, vegetation attributes, and soil properties in wetlands (WL), farmlands (FL), and alpine meadow (AM) ecosystems in Zhejiang Province, China.

Grassland coverage change and its humanity effect factors quantitative assessment in Zhejiang province, China, 1980-2018.

This study aims to make clear of grassland coverage change and quantitative assessment its effect factors. We collected the data from the National Bureau of Statistics ( http://www.stats.

Plant canopy may promote seed dispersal by wind.

Seed dispersal has received much research attention. The plant canopy can intercept diaspores, but the effect of the plant canopy (the aboveground portion of a plant consisting of branches and leaves) on dispersal distance has not been explored empirically. To determine the effect of plant canopy on seed dispersal distance, a comparison of diaspores falling through open air and through plant canopy was made in a wind tunnel using three wind speeds and diaspores with various traits.

Effects of climatic and social factors on dispersal strategies of alien species across China.

Determination of dispersal strategies of alien species and its relationship with social and climatic factors are essential to understand the mechanisms of species invasion and adaption. Based on morphological trait, dispersal mode, and dispersal agent of diaspore of 562 alien species across China, we determined: (i) the proportions of five dispersal strategies (i.e.

Wing loading, not terminal velocity, is the best parameter to predict capacity of diaspores for secondary wind dispersal.

Lift-off velocity may be the most useful surrogate to measure the secondary dispersal capacity of diaspores. However, the most important diaspore attribute determining diaspore lift-off velocity is unclear. Furthermore, it is not known whether terminal velocity used to characterize the primary dispersal capacity of diaspores can also be used to predict their secondary wind dispersal capacity.

Geographical distribution and determining factors of different invasive ranks of alien species across China.

Determination of the geographical distribution and life-form spectra of alien species with different invasive abilities are essential to understand the process of invasion and to develop measures to manage alien species. Based on six classifications of Chinese alien species, environmental and social data, we determined species density, life-form spectrum of alien species, and the relationship between species density of alien species and climatic or social factors. The species density of alien species increased from the northwest to the southeast regions of China for all the six ranks.

Relationship between seed morphological traits and wind dispersal trajectory.

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.

Phosphorus vertical migration in aquic brown soil and light chernozem under different phosphorous application rate: a soil column leaching experiment.

A soil column leaching experiment was conducted to study the vertical migration of phosphorus in aquic brown soil and light chernozem under different phosphorus fertilization rates. The results showed that total dissolved phosphorus concentration in the leachates from the two soils was nearly the same, but dissolved inorganic phosphorus concentration was obviously different. In all fertilization treatments, aquic brown soil had a higher content of phosphorus in calcium chloride extracts compared with light chernozem.

[Effects of P application on P concentrations in paddy soil and its surface water: a simulation test].

An anaerobic incubation test was conducted to study the effects of different P application rate on the P concentrations in paddy soil and its surface water. The results showed that soil available P (Olsen-P) decreased rapidly at the beginning, but approached to stable after 60 days of P application. Both Olsen-P and residual P increased with increasing P application rate, and Olsen-P had a positive correlation with P application rate, suggesting that the test soil had a strong P adsorption capacity.