卧龙自然保护区落叶松林不同恢复阶段地表甲虫的多样性

Diversity of Ground-Dwelling Beetles (Coleoptera) in Larch Plantation with Different Stages of Reforestation in Wolong Natural Reserve, Southwestern China

在四川卧龙国家自然保护区,以落叶松种植林邻近的天然落叶阔叶林(100年生,5块样地)为对照,分别选择刚种植(5年生)、幼年期(15年生)和成熟期(45年生)的3种落叶松林各4块样地,每个样地4个重复,研究森林不同恢复阶段地表甲虫的多样性。通过巴氏罐诱法取样,采集甲虫标本共7444号。步甲科、隐翅虫科和拟步甲科分别占总数的40·2%、38·3%和6·4%,共同构成本研究地区的优势类群。甲虫的科丰富度、多样性和均匀度在3种落叶松林内显著高于天然林,且在3种落叶松林中,刚种植的最高,幼年期的最低;个体数量正相反,天然林显著高于落叶松林,而且3种落叶松林内,幼年期最高,刚种植的最低。主坐标分析排序和聚类分析表明,不同树龄的落叶松林和天然阔叶林间的地表甲虫群落组成存在显著差异,成熟期落叶松林与幼年期落叶松林和天然阔叶林有较高的相似性。甲虫个体数量的季节变化在3种落叶松林内相似性很高,与天然阔叶林差异显著,而科丰富度、多样性和均匀度的季节变化在3种落叶松林以及天然阔叶林间相似性都很低。多元回归分析表明,林冠层、草本层及枯落物的高(厚)度和覆盖率是决定科丰富度、个体数量、多样性和均匀度的决定因素。以上结果表明,在科级水平上,地表甲虫群落组成在不同树龄的落叶松林以及天然落叶阔叶林内存在显著差异,虽然成熟期的落叶松林已经具有了部分天然阔叶林的甲虫群落特点,但仍无法完全恢复到天然林的群落水平。因此,在鼓励森林恢复的同时,保留大面积的天然落叶阔叶林免受破坏和干扰仍然是保护地表甲虫群落的必要措施。

This paper studied the influences of forest regeneration on the diversity of ground-dwelling beetles （Coleoptera）, in taxonomic level of families, in Wolong Natural Reserve （30°45′ - 31°25°N, 102°52′ - 103°24′E）, Southwestern China. Comparisons were conducted among larch plantations of different forest ages, namely, recently planted （5 years old）, young （15 years old）, mature plantation （45 years old）, and natural deciduous broad-leaved forests （ca. 100 years old）. Larch plantations were dominated by non-native Larix kaempferi but interspersed with a few native L. mastersian. Pitfall traps were used in the field collections. During the field research, a total of 7444 beetles were collected, of which, Carabidae accounted for 40.2%, Staphylinidae 38.3%, and Tenebrionidae 6.4%, and these three families were considered as dominant groups. Family richness, diversity and evenness of beetles were significantly higher in three larch plantations than in natural broad-leaved forest ; among the three plantations, the highest values were observed in the recently planted whereas the lowest in the young plantation. Contrary to the above three indices, family abundance was higher in natural broad-leaved forest than in three larch plantations; within the three plantations, the lowest value were showed in the recently planted whereas the highest value in the young plantation. Based on the family composition and abundance, ground-dwelling beetles of three larch plantations and the adjacent natural broad-leaved forest could be separated by ordinations of principal coordinate analysis （PCO） and cluster analysis, but beetle assemblages in the mature plantation was similar to both natural forest assemblages and young plantation assembalges. Seasonal dynamics of family abundance were similar among the three plantations, but significantly different from that of the natural broad-leaved forest. However, family richness, diversity and evenness did not show the similar trends. Multiple linear regression analyses showed that the coverage and height （or depth） of canopy layer, herbaceous layer and leaf litter layer were the most important factors in determining the family richness, abundance, diversity ; and evenness. Although some similar characteristics in beetle composition were displayed in the mature plantation as well as in the natural broad-leaved forest, our results showed that the composition of ground-dwelling beetles in larch plantations differed obviously from those in the natural deciduous broadleaved forest at the family level. Finally we concluded that, in an attempt at reforestation by the establishment of plantations, it is necessary to preserve the undisturbed deciduous broad-leaved forest for the purpose of protecting the diversity of ground-dwelling beetles in Wolong Natural Reserve.