Study On Quantitative Dynamics Of Insect Along Successional Gradient In Broad-leaved And Korean Pine Mixed Forests In The Changbai Mountain, China

The original broad-leaved Korean pine forest is the zonal climax vegetation type in the western of Changbai Mountain. Since the 20th century, the resource of original broad-leaved Korean pine forest has been seriously destroyed in Changbai Mountain, which resulting in a large area of secondary forest community. It was noted that insect community was a powerful indicator of forest discover and succession. We examined the changes in species diversity and faunal composition of insect along a successional gradient of conifer and broad-leaved mixed forests in Changbai Mountain by using sweeping nets, light traps and pitfall traps. According to different taxa of insect biology, ecology, taxonomic characteristics, moth, butterfly and ground beetle were selected to study their diversity and community structure, and to find the relationship between diversity and environment factors. The brief results are as follows:1. Insect community along a successional gradient in Broad-leaved and Korean pine mixed forests in the Changbai MountainsInsect community of three habitats, secondary birch forest (SBF), secondary conifer and broad-leaved mixed forest (SCBF), original broad-leaved Korean pine forest (OBPF), from the early successional stage to mature forest understory were investigated. The results showed that a total of 8 183 individuals, consisting of 699 species in 362 orders, were recorded. The dominant species were Lepidoptera and Coleoptera. SCBF had the largest number of individuals and OBPF had the largest number of species, but the number of species and individuals along the successional habitats did not differ significantly. The Fisher'αindex of SCBF and OBPF was significantly greater than that of SBF, and the diversity on the family level was not significantly difference in three habitats.Insect diversity increased following the herb diversity along the successional habitats. Because of difference feeding habits and habitat preference the diversity of Lepidoptera increased along the successional habitats, while that of Coleoptera decreased, which was similar to those found in previous studies.2. Diversity and composition of moths along a successional gradient in Broad-leaved and Korean pine mixed forests in the Changbai MountainsSpecies composition and diversity of moths was studied in different recovery stage mixed forests in Changbaishan in this paper, and the associations between composition of families of moths and forest types were also analyzed. The results showed that,6520 individuals, which classified into 23 families and 410 species, were recoded in 2006 and 2007. Species richness, Fisher'a and eH' were the highest in mature forest, Species-abundance curve of moths can be modeled by logarithm distribution in all 4 studied forests, and this accords with the niche-preemtion hypothesis. AVONA analysis indicated that, the number of moths in Lithosiidae, Noctuidae, Pyralidae, Arctiidae and Tortricidae related significantly with forest recovery degree. But contrary conclusions were found in Geometridae, Limacodidae, Sphingidae and Notodontidae.3. Diversity and community structure of ground-dwelling beetle (Coleoptera) along a succession gradient in Broad-leaved and Korean pine mixed forests in the Changbai MountainsStudies of ground-dwelling beetle on three habitats along a succession gradient were carried out from June to August 2007 in broad-leaved Korean pine forest zone of Changbai Mountain using pitfall trapping. A total of 511 individuals and 23 species were identified. The dominant species was Carabidae and Silphidae assemblage. The number of species and individuals in the secondary birch forest was greater than in the secondary conifer and broad-leaved mixed forest and original broadleaved Korean pine forest. From this study, it appears that the composition and diversity of ground-dwelling beetle was determined by succession stages. The earlier succession stage, secondary birch forest, had higher diversity than climax forest community. There was significant difference about species and individuals in July. Species accumulation curves did not reach an asymptote, the actual species richness values of the secondary conifer and broad-leaved mixed forest and original broadleaved Korean pine forest were within the 95% confidence intervals, but that of the secondary birch forest was lower than the minimum estimated value. The species-abundance distributions for the three habitats fit the log series distributions. The result of DCA showed that the dominance species of all sites was similar; the difference of habitats was made by occasional species. According to analysis of RDA, the area of breast height and soil moisture was mainly environment factors affected ground-dwelling beetle distribution.4 Diversity and community structure of butterfly along a succession gradient in Broad-leaved and Korean pine mixed forests in the Changbai MountainsWe sampled a total of 72 species and 537 individuals, representing 7 families, from all three habitats. The number of species was not even distributed over the study sites. Focus on 13 dominate species, only 2 species were distributed all habitats, Nymphalidae is the most in number of species and individuals of all families.Crown density and human disturbance are important factors for butterfly in difference habitats.5. Effects of temperature and rainfall on composition and diversity of butterflies in Broad-leaved and Korean Pine Mixed Forest in Changbai MountainThe butterflies in broad-leaved and Korean pine mixed forest of the Changbai Mountain were investigated by the line transect method to analyze the relationship between butterflies diversity and weather variables from 2005 to 2007. The study was focused on the effects of temperature and rainfall on species composition and diversity of butterflies. A total of 768 individuals were captured and identified, belonging to 69 species in 7 families. The results of stepwise regression analyses showed that the mean temperature affected the species richness, but rainfall had a negative relation with the species abundance of butterflies. The study also revealed that each family was impacted by a set of different weather factors due to different life-history stages, and rainfall (R) and accumulative temperature of previous three months (T-3) are important factors for Pieridae, Nymphalidae and Satyridae. The relationship between dominant species and weather factors was significantly different. The effect of other weather factors on the diversity of butterfly species needs to be further studied.