小兴安岭阔叶红松林地表甲虫Metacommunity格局

Metacommunity理论框架为理解生物群落的时空格局及其构建机制提供了一个强有力的方法。然而,少有研究揭示土壤动物metacommunity的格局及其构建机制,小尺度空间的研究更是少见。于2015年分别在凉水和丰林小兴安岭典型阔叶红松林长期动态监测样地内,通过空间直观定位调查监测的方法获得地表甲虫群落,揭示小尺度空间(300 m)地表甲虫metacommunity的格局,并进一步分析地形、土壤因子与这种metacommunity格局的相关性。结果表明:镶嵌型(nestedness)和随机型(random)是小尺度空间地表甲虫metacommunity的常见格局。地表甲虫的metacommunity格局具有类群依赖性,步行虫科和葬甲科多形成镶嵌型格局,而隐翅虫科则仅形成随机型格局。地表甲虫metacommunity格局具有季节波动性,在相对温暖的季节易形成显著的镶嵌型格局,而在相对寒冷的季节多为随机型格局。凉水和丰林地表甲虫的metacommunity格局没有明显差异。地形和土壤因子对地表甲虫metacommunity格局有重要的影响,该影响过程相对复杂,依类群和时间而异。本实验表明镶嵌型和随机型是小尺度空间小兴安岭典型阔叶红松林地表甲虫的常见格局,地形、土壤因子对这些格局的形成有重要的影响。

Metacommunity patterns of ground-beetle assemblages in two mixed broad-leaved Korean pine (Pinus koraiensis) forests in the Xiao Xing'an Mountains

A metacommunity is defined as a set of local communities that are linked by the dispersal of multiple potentially interacting species. Metacommunity theory framework provides a powerful method for the understanding of spatio-temporal patterns and explaining the underlying processes of a community structuring. Metacommunity framework has been used in various organism communities (including plant, bat, arbuscular mycorrhizal fungi, bird, and invertebrate communities). However, few studies have been used to recognize the metacommunity patterns and their underlying processes for soil animal communities at multiple scales, especially at small scales. In 2015, an experiment was conducted in two permanent dynamic monitoring plots in two typical mixed broad-leaved Korean pine (Pinus koraiensis) forests in the Liangshui (LS) and Fenglin (FL) National Nature Reserves. Each plot consisted of a 9-hm² area with 300 m×300 m and was equally divided into 225 squares by 20 m. Based on a spatially explicitly investigating method, ground beetles were collected by pitfall traps in July, August, and October in the LS plot and in August and October in the FL plot. The topographic variables, that is elevation, slope convexity, slope steepness and slope aspect, were measured for each square both in LS and FL plots. The soil variables, including bulk density, soil organic carbon content, total nitrogen, available phosphorus, total phosphorus, pH, available potassium, hydrolyzable nitrogen and soil moisture, were measured for each square in LS plot. The metacommunity patterns of ground beetles were determined by elements of metacommunity structure (EMS). We evaluated if the Clementsian pattern is common for ground beetle metacommunities at such small scales. Then we explained the association between the site scores along the first axis of the reciprocal averaging and geographic and/or soil variables by Spearman rank correlation. Results of the EMS showed that nestedness and random patterns were common for ground beetle metacommunities at small scales, such as in the two studied typical mixed broad-leaved Korean pine forests. The Clementsian pattern was not detected for any ground beetle metacommunity. Moreover, metacommunity patterns of ground beetles were group-dependent. Metacommunity patterns were nestedness for Carabid and Silphidae beetles, while metacommunity patterns were random for Staphylinidae beetles. At the same time, metacommunity patterns of ground beetles were seasonal dynamic. The nestedness patterns were formed in warm seasons (i.e. July and August), and the random patterns were formed in a relatively cool season (October). Metacommunity patterns between the LS and FL plots were not significantly different. The site scores along the first axis of the reciprocal averaging were correlated with topographic and/or soil variables for Carabid, Silphidae, and total beetle communities. Important factors included mean elevation, aspect, slope, total nitrogen, pH, and soil organic matter content. These variables were suggested influences on ground beetle metacommunity patterns. However, the influences were relatively complicated and were group-dependent and season-dependent. This study suggests that nestedness and random patterns are common for ground beetle metacommunities at small scales in the typical mixed broad-leaved Korean pine forests in the Xiao Xing''an Mountains. Additionally, topographic and soil variables may be important factors for formatting these metacommunity patterns.