The Animal Community Structure And Diversity In Forest-steppe Ecotone

Ecotone is the transitional zone between the adjacent ecosystems, which ecological structure and function change rapidly in the time scale and spatial scale, and which is a special area to have high biodiversity, sensitive to global changes and edge effects. But, the specific ecotone only can be monitored in a specific time and space scales, so ecotone is the core issues to proceed early ecological warning and ecological management.Forest-steppe ecotone is an important type of land ecotone. At present, the study on China's forest-steppe ecotone is focused on the botany, but the animal communities is lack of the information to be reported.The forest-steppe ecotone of Inner Mongolia plateau southeast edge locates in the border between the Weichang County of Hebei Province and Chifeng City of Inner Mongolia (116°32'-117°33'E, 42°10'-43°18'N). The area belong to the intersection area of the southeast edge of Inner Mongolia plateau, DaXing'an Mountains and the northern Hebei mountain, which is a typical large-scale forest t-steppe ecotone in China, and the forest and grassland is inlaid with in the area. The animal community structure and diversity of Arthropods, soil animals and Vertebrates were studied from April 2004 to October 2007 by the method of strip transect sampling. The results showed that:The composition of animal community was rich in the forest-steppe ecotone of Inner Mongolia plateau southeast edge. Total of 2 classes 15 orders 77 families 326 species of Arthropods, 6 Phylum 11 classes 27 orders (groups) of soil animals and 4 classes 23 orders 54 families 126 genus 195 species of Vertebrates were found. Ominant groups of Arthropods were Araneida, Diptera, Homoptera and Hymenoptera. Ominant groups of large-sized soil animal included Microdrile oligochaetes, Coleoptera and Stylommatophora, ominant groups of middle-small-sized soil animal included Acarina and Collembola, ominant group of wetlands soil animal was Rhabditidia. Ominant species of Vertebrates were Eremias argus, Parus palustris hellmayri, Phylloscopus inornatus inornatus, Emberiza coides weigololi, Phoenicurus auroreus auroreus, Pica pica cenicea, Lanius cristatus lucionensis, Lepus capensis, Citellus dauricus and Eutamias sibiricus.Animal community structure and diversity showed a marked gradient changes with the level environmental gradients. In all the animal groups, there were the maximum individual number, species (groups) number and species (groups) diversity, which were higher or significantly higher than that of either side of the forest zone and steppe zone, and the result showed that the large-scale forest-steppe ecotone had a significant edge effects. The species replacement rate of Vertebrates (birds) changed significantly with vegetation zones in step by step, the relation between replacement rate of species and the environment gradient "steepness" was closely. The animal communities between different types of vegetation were different significantly, and different animal groups changed in different way. The individual number, species number and species diversity of Arthropods were the maximum in belt between forests, the species diversity in most of coniferous forest were higher than it in broad-leaved forest. The individual number and group number in most of broad-leaved forest were higher than it in coniferous forest. The individual number and species number in coniferous forest were higher than it in broad-leaved forest.Animal community structure and diversity showed a marked gradient changes with the vertical environmental gradients. Arthropods communities were extremely significant difference among the tree layer, shrub layer, herbaceous layer and leaf litter layer, the individual number, species number, species diversity and evenness index of Arthropods were the maximum in herbaceous layer. The soil animal communities were different among the leaf litter layer, 0～5cm layer,5～10cm layer and 10～15 layer, the largest number of the individual number and groups number were in the leaf litter layer. The most notable changes happened from leaf litter layer to 0～5cm layer, and there were on notable changes from 5～10cm layer to 10～15 layer, but the groups number of Pinus tabulaeformis forest showed the opposite phenomenon. Bird communities showed different vertical changes in different vegetation zones. In habitat height (five layers of Ground, 0～5m,5～10m,10～15m and >15m), the species diversity were the maximum in 5～10m layer of forest zone and forest-meadow, and the maximum in 0～5m layer of meadow-steppe. In habitat position (three layers of branch, trunck and ground) , all of the species diversity were the maximum in trunck.Animal community structure and diversity showed the marked seasonal changes., The maximum of Arthropod's individual number, species number and species diversity were in late July - early August. The groups number of soil animals was the maximum in summer, and the individual number was the maximum in autumn. The species number of birds; was the maximum in spring, the main species of bird community were migratory birds (summer migratory birds) in spring and summer, and the main species of bird community were resident birds in autumn and winter. Animal community structure and diversity are closely related with environmental factors. There was a significant correlation between the species diversity, evenness index of Arthropods and forest patch number, forest coverage rate, and a significant correlation between the individual number, species number and forest patch number, average patch size, forest coverage rate. There was a significant positive correlation between the individual number, groups number of soil animals and PH value, humidity of soil. The species diversity had a positive correlation with PH value of soil and a a negative correlation with humidity of soil. There was a significant positive correlation between the bird's individual number, species number, species diversity and forest patch number. There was a significant correlation between the Arthropods, Vertebrates (birds) and large-scale space environmental factors, the main factors to affect their community structure and diversity were forest patch number, average patch size or forest coverage rate. The main factors to affect soil animals community were PH value and humidity of soil.The artificial coniferous forest plantations restoration had the evident effect to the species diversity and feeding guilds of bird communities in degraded forest ecosystem. The artificial coniferous forest had provided 58.97 percent of local bird species after restoration for 40 years. Compared with the natural recovery, artificial coniferous forest not only increased the number of species of bird community, but also significantly increased the density of birds, especially to significantly increase the density of Parus palustris hellmayri and Phylloscopus inornatus inornatus. In four birds feeding guilds, the density of insectivore had significantly increased in artificial coniferous forest after restoration for 40 years.