雷州半岛风水林中无患子的空间分布格局与空间关联性

Spatial Distribution Pattern and Association of Sapindus saponaria in Fengshui Forest, Leizhou Peninsula

为探讨无患子(Sapindus saponaria)在生态修复和城市园林中的应用,在广东湛江雷州市龙门镇足荣村无患子风水林设置1 hm;样地,调查群落的物种组成,并采用点格局分析法,结合完全随机零模型和异质泊松零模型,分析无患子的空间分布格局与关联性。结果表明,样地中胸径≥1 cm的乔木共计28科60属73种3 585株,其中单属科、单种科、单种属的比例最高,其次为寡属科、寡种科、寡种属。无患子总体在0~25 m研究尺度上呈聚集分布、随机分布和均匀分布交替出现的现象;在小尺度上,幼树呈聚集分布,成年树呈均匀分布,但随着尺度增大,3个龄级个体主要呈随机分布;幼树与中龄树呈微弱的空间正关联,而幼树与成年树呈空间无显著关联;中龄树与成年树呈周期性变化,由空间无显著关联(0~4.5m)到空间正关联(4.5~10.0 m)再到空间无关联(10.0~25.0 m)。无患子在空间分布格局上从小尺度上的聚集分布过渡为大尺度上的随机分布,可能存在一定程度的邻体竞争和密度制约;幼树和中龄树共存比例高;幼树和成年树则相对独立;中龄树和成年树在局部尺度共存比例也较高。因此,在雷州半岛生态修复和城市园林建设过程中,无患子可小范围聚集栽培,大面积分散栽培。

To explore the application of Sapindus saponaria in ecological restoration and urban garden, a 1 hm;plot was set up in S. saponaria Fengshui Forest in Zorong Village, Longmen Town, Leizhou City, Guangdong Province, the species composition of community was analyzed, and its spatial distribution pattern and intraspecific correlation were also analyzed using a point pattern analysis with complete spatial randomness and heterogeneous poisson. The results showed that there were 3 585 individuals of 73 species, belonging to 60 genera and 28 families with diameter at the breast height(DBH)≥1 cm. The proportion of the monogeneric family, singlespecies family and monotypic genus were obviously higher than other types, followed by the oligogenera families,oligospecies families and oligotypic genera. The spatial distribution patterns of S. saponaria showed an alternating phenomenon of aggregation, random distribution and uniform distribution at 0-25 m scales. At a small scale, the distribution of saplings was aggregated, and that of adults was uniform. With the increment of spatial scale, trees in three age classes were mainly randomly distributed. The saplings and middle-aged trees had a weak positive association at 0-25 m scales, while it was negatively associated between saplings and adult trees. The association between middle-aged and adult trees showed periodic changes, from no significant association(0-4.5 m scale) to positive association(4.5-10.0 m scale) to no association(10.0-25.0 m scale). As a consequence of neighbor competition and density dependence, the spatial distribution pattern of S. saponaria changed from aggregated distribution at small scale to random distribution at large scale. The coexisting proportion of saplings and middle aged trees was high, and that of middle-aged and adult trees at small scales also high, while saplings and adult trees are relatively independent. Therefore, S. saponaria could be cultivated in small aggregations and scattered in large scales for the ecological restoration and urban garden construction in Leizhou Peninsula.