基于生灭过程的二维毒杂草入侵模型的构建及模拟

为了解我国毒杂草入侵可食牧草的机理,保护农业和畜牧业的持续发展,建立二维生灭过程毒杂草入侵模型。以当地可食牧草系统受到外来毒杂草入侵为背景,建模计算生态系统中的平均生物量和平均续存时间,并通过计算机模拟方法截取时间截面得到当地可食牧草和入侵毒杂草的空间分布数据,再进行空间分布类型的假设检验。结果表明,阻滞作用会限制可食牧草生物量的增长,使其在达到环境容纳量时不再增长。在对可食牧草加入阻滞项后,可食牧草由之前的第8个时间点推后到第12个时间点变为聚集分布,而此时毒杂草从第8个时间点提前到第6个时间点变为聚集分布。在对毒杂草加入入侵项后,可食牧草变为聚集分布的时间由第8个时间点变为第9个时间点,而毒杂草变为聚集分布的时间提前了1个时间点,由第7个时间点变为聚集分布。因此,可食牧草的阻滞增长和毒杂草的入侵作用均会对种群的空间分布产生影响,二者均推迟了可食牧草聚集的时间,同时使得毒杂草变为聚集分布的时间提前。

Two-dimensional poisonous weed invasion model based on birth and death process

In order to understand the mechanism of edible pasture invaded by poisonous weeds in China and protect the sustainable development of agriculture and animal husbandry, a two-dimensional poisonous weed invasion model was established. Based on the invasion of local edible pasture system by exotic weeds, the average biomass and mean survival time of the ecosystem were calculated by modeling. The spatial distribution data of local edible pasture and poisonous weeds were obtained by computer simulation method, and then the hypothesis test of spatial distribution types was carried out. The results showed that the edible pasture with block growth would not grow when the environmental capacity was reached. After adding the block growth to the edible pasture, the aggregate distribution time point of edible pasture was pushed from the 8th time point to the 12th time point, and the aggregate distribution time point of poisonous weeds were advanced from the 8th time point to the 6th time point. After adding the invasive item to the poisonous weeds, the aggregate distribution of edible pasture changed from the 8th time point to the 9th time point and the poisonous weed were advanced by a time point. Therefore, the block growth of edible pasture and the invasion of poisonous weeds could affect the spatial distribution of the population, both of which delay the accumulation of edible pastures, and made the time for the aggregation of poisonous weed to advance.