Plant crown can affect the seed dispersal process.Clarifying the influence of plant crown type on seed dispersal kernel is important for predicting species distribution.However,the effects of different plant crown typ...Plant crown can affect the seed dispersal process.Clarifying the influence of plant crown type on seed dispersal kernel is important for predicting species distribution.However,the effects of different plant crown types on seed dispersal have rarely been tested.To address this,we conducted wind tunnel experiments to investigate the average seed dispersal distance,range,kurtosis and skewness of 29 species with varying diaspore traits(e.g.,appendage type,mass,projected area,shape index,wing loading and terminal velocity)under 3 wind speeds(2,4 and 6 m s^(-1)).We examined seeds passing through different crown types,classified based on crown size,branch density,and the presence or absence of leaves.We fitted functions to the seed dispersal distance and found that the Gaussian function provided the best fit.Our results showed that plant crown type had significant effects on dispersal kurtosis and skewness but not on the average dispersal distance or range under low wind speed conditions.Specifically,crown width and branch density influenced dispersal kurtosis,while the presence of leaves affected both kurtosis and skewness.Increasing wind speed reduced the influence of plant crowns on dispersal kurtosis and skewness.Although plant crowns did not significantly affect average seed dispersal distance,they altered the shape of the seed dispersal kernel.Consequently,while the dispersal range of seeds through different crowns remained relatively invariant,the density of dispersal varied significantly.These findings provide valuable insights into plant metapopulation dynamics and highlight the importance of considering crown architecture in seed dispersal studies.展开更多
In order to investigate the diffusion patterns of Eupatorium adenophorum, this study uses a computer to simulate various plant diffusion processes under different environments. The study develops binary cellular autom...In order to investigate the diffusion patterns of Eupatorium adenophorum, this study uses a computer to simulate various plant diffusion processes under different environments. The study develops binary cellular automata as a framework reflecting the growth and semination of plants by the change of cellular state and transition function. This model allocates 16 integers, namely 1 to 16, to indicate a life history of plant starting from seed. In each iteration （a year）, Monte-Carlo simulation is applied to decide whether an individual survives into the next year, the probability of which is estimated from previous literature. If a plant survives youth, mature or senile period, its propagation will also be considered and short-tailed dispersal kernel was employed. Applying this basic model, this study also simulates the diffusion process of E. adenophorum under four typical ecological environments. Examining the age structure of the four populations, we found that, although with significantly different numbers of plants left, most individuals were in the infancy period. Besides, their dispersal velocity showed different periodic law. These observations provided reasonable suggestions on what control strategies to be taken respectively.展开更多
This paper studies an epidemic model with nonlocal dispersals.We focus on the influences of initial data and nonlocal dispersals on its spatial propagation.Here,initial data stand for the spatial concentrations of the...This paper studies an epidemic model with nonlocal dispersals.We focus on the influences of initial data and nonlocal dispersals on its spatial propagation.Here,initial data stand for the spatial concentrations of the infectious agent and the infectious human population when the epidemic breaks out and the nonlocal dispersals mean their diffusion strategies.Two types of initial data decaying to zero exponentially or faster are considered.For the first type,we show that spreading speeds are two constants whose signs change with the number of elements in some set.Moreover,we find an interesting phenomenon:the asymmetry of nonlocal dispersals can influence the propagating directions of the solutions and the stability of steady states.For the second type,we show that the spreading speed is decreasing with respect to the exponentially decaying rate of initial data,and further,its minimum value coincides with the spreading speed for the first type.In addition,we give some results about the nonexistence of traveling wave solutions and the monotone property of the solutions.Finally,some applications are presented to illustrate the theoretical results.展开更多
基金financiallyysupported by the Shandong Provincial Natural Science Foundation(ZR2022QC259)National Natural Science Foundation of China(41571270)China Postdoctoral Science Foundation(2024M753463).
文摘Plant crown can affect the seed dispersal process.Clarifying the influence of plant crown type on seed dispersal kernel is important for predicting species distribution.However,the effects of different plant crown types on seed dispersal have rarely been tested.To address this,we conducted wind tunnel experiments to investigate the average seed dispersal distance,range,kurtosis and skewness of 29 species with varying diaspore traits(e.g.,appendage type,mass,projected area,shape index,wing loading and terminal velocity)under 3 wind speeds(2,4 and 6 m s^(-1)).We examined seeds passing through different crown types,classified based on crown size,branch density,and the presence or absence of leaves.We fitted functions to the seed dispersal distance and found that the Gaussian function provided the best fit.Our results showed that plant crown type had significant effects on dispersal kurtosis and skewness but not on the average dispersal distance or range under low wind speed conditions.Specifically,crown width and branch density influenced dispersal kurtosis,while the presence of leaves affected both kurtosis and skewness.Increasing wind speed reduced the influence of plant crowns on dispersal kurtosis and skewness.Although plant crowns did not significantly affect average seed dispersal distance,they altered the shape of the seed dispersal kernel.Consequently,while the dispersal range of seeds through different crowns remained relatively invariant,the density of dispersal varied significantly.These findings provide valuable insights into plant metapopulation dynamics and highlight the importance of considering crown architecture in seed dispersal studies.
基金supported by the National Natural Science Foundation of China (Grant No.30870231)the National Undergraduate Innovative Experiment Project of China
文摘In order to investigate the diffusion patterns of Eupatorium adenophorum, this study uses a computer to simulate various plant diffusion processes under different environments. The study develops binary cellular automata as a framework reflecting the growth and semination of plants by the change of cellular state and transition function. This model allocates 16 integers, namely 1 to 16, to indicate a life history of plant starting from seed. In each iteration （a year）, Monte-Carlo simulation is applied to decide whether an individual survives into the next year, the probability of which is estimated from previous literature. If a plant survives youth, mature or senile period, its propagation will also be considered and short-tailed dispersal kernel was employed. Applying this basic model, this study also simulates the diffusion process of E. adenophorum under four typical ecological environments. Examining the age structure of the four populations, we found that, although with significantly different numbers of plants left, most individuals were in the infancy period. Besides, their dispersal velocity showed different periodic law. These observations provided reasonable suggestions on what control strategies to be taken respectively.
基金supported by China Postdoctoral Science Foundation(Grant No.2019M660047)supported by National Natural Science Foundation of China(Grant Nos.11731005 and 11671180)supported by National Science Foundation of USA(Grant No.DMS-1853622)。
文摘This paper studies an epidemic model with nonlocal dispersals.We focus on the influences of initial data and nonlocal dispersals on its spatial propagation.Here,initial data stand for the spatial concentrations of the infectious agent and the infectious human population when the epidemic breaks out and the nonlocal dispersals mean their diffusion strategies.Two types of initial data decaying to zero exponentially or faster are considered.For the first type,we show that spreading speeds are two constants whose signs change with the number of elements in some set.Moreover,we find an interesting phenomenon:the asymmetry of nonlocal dispersals can influence the propagating directions of the solutions and the stability of steady states.For the second type,we show that the spreading speed is decreasing with respect to the exponentially decaying rate of initial data,and further,its minimum value coincides with the spreading speed for the first type.In addition,we give some results about the nonexistence of traveling wave solutions and the monotone property of the solutions.Finally,some applications are presented to illustrate the theoretical results.
