高原鼠兔和高原鼢鼠种群暴发区干扰斑块空间分布格局与演替规律

高原鼠兔(Ochotona curzoniae)和高原鼢鼠(Myospalax baileyi)是两种在高寒草甸广泛分布的小型哺乳动物，其暴发活动可能造成高寒草甸的严重退化。使用无人机分别拍摄典型的高原鼠兔和高原鼢鼠种群暴发区图像，解译高原鼠兔洞口、高原鼢鼠土丘和它们的干扰斑块，获得干扰斑块的周长和面积信息，计算干扰斑块形状指标，确定高原鼠兔与高原鼢鼠暴发活动对高寒草甸的影响。研究表明：(1)高原鼠兔与高原鼢鼠暴发活动形成的干扰斑块周长与面积比(PARA)、形状指数(SHAPE)和分形维数(FRAC)差异显著(P<0.05),其中高原鼢鼠斑块的FRAC是1.0124±0.0091,属于普通的规则几何圆形分布格局，高原鼠兔斑块的FRAC是1.1203±0.0546,属于分形几何不规则的分布格局。(2)高原鼠兔洞口数量与其斑块面积没有线性相关关系(P=0.9677),高原鼢鼠土丘数量与其斑块面积呈显著正相关(P<0.05)。(3)高原鼢鼠斑块面积统计学上呈长尾分布，不符合正态分布(P<0.01)。根据高原鼠兔斑块面积分布格局可将斑块演替分为三个阶段：土丘形成阶段、斑块连通...

Spatial distribution pattern and succession of disturbance patches formed by plateau pika and plateau zokor in their population outbreak areas in alpine meadow

Plateau pika (Ochotona curzoniae) and plateau zokor (Myospalax baileyi) are two species of small mammal widely distributed in alpine meadow. The main difference between the two animals is that plateau zokor mainly lives underground and plateau pika mainly lives on the surface of grassland. Their outbreak activities may cause serious degradation of alpine meadow. The disturbance patches formed by the two animals have different effects on the alpine meadow. Which kind of animal outbreak can lead to the cross-scale succession of disturbance patches is a scientific problem that needs to be solved. The patch shape and pattern metric in the field of landscape ecology can be used to compare the patch distribution patterns, thereby understanding the differences in the formation process of various patches. In this study, Unmanned aerial vehicle (UAVs) were used to capture typical images of plateau pika and plateau zokor population outbreak areas. Plateau pika holes, plateau zokor mounds and their disturbance patches were interpreted. The perimeter and area information of the disturbance patch was obtained. The shape and pattern metrics of disturbance patch were calculated and analyzed. The effects of outbreak activities of plateau pika and plateau zokor on the degradation of alpine meadow were determined. The results indicated that (1) there were significant differences in perimeter-area ratio (PARA), shape index (SHAPE) and fractal dimension index (FRAC) between plateau pika and plateau zokor disturbance patches formed by their outbreak activities (P<0.05). The FRAC of plateau zokor patches was 1.0132±0.0103, which belongs to ordinary regular geometry (circle), and the FRAC of plateau pika patches was 1.1007±0.0576, which belongs to fractal geometry. (2) There was no correlation between the number of plateau pika holes and the patch area of plateau pika (P=0.9677). There was a significantly positive correlation between the number of mounds and the patch area of plateau zokor (P<0.05). (3) The area of plateau zokor patch showed a long tail distribution at statistics, which did not accord with the normal distribution (P<0.01). According to the patch distribution pattern of plateau pika, the succession of patches could be divided into three stages:mound stage, fusion stage and broad-scale stage. The shape and distribution pattern of patches at the mound stage were similar to those of plateau zokor patches. At the fusion stage, the patch distribution was exponential, and the shape and pattern belonged to fractal geometry (FRAC=1.1161). At the broad-scale stage, the patch pattern was large and the shape was complex (SHAPE=4.4202). The patches at the broad-scale stage were formed by the connection between the surrounding fusion stage patches and the core area of black soil degraded patches, which destroyed the dynamic balance between disturbance and restoration of alpine meadow. There were significant differences among PARA, SHAPE and FRAC at the three stages (P<0.05). The foraging activities of plateau pika in the degradation of alpine meadow promoted the formation of patches and formed fractal geometric patches at the fusion stage. The main cross-scale interaction resulting in the degradation of alpine meadow was caused by the outbreak of plateau pika, not plateau zokor. Therefore, it is more important to control the number of plateau pika and restore the disturbance patches of plateau pika than those of plateau zokor.