贺兰山地表甲虫多样性分布格局及环境解释

Helan Mountain is the core region of the Alashan Ordos area，which is one of biodiversity centres in China. Study on biodiversity distribution patterns in Helan Mountain and formation mechanism is important significance of conservation biology. Species composition and individual fluctuation of ground-dwelling beetles can be as an important indicator of environment and biodiversity changes, Which is extremely sensitive to habitats changes. In this project, we try to elucidate the spatial distribution of diversity of ground-dwelling beetles and the affect of environmental factors on it based on the detailed field investigation, combined with high spatial resolution remote sensing data (RS) and a digital elevation model (DEM). First, various ecological factors under different topographical conditions with vegetation vertical belt were extracted and terrain differentiation distribution rules map were expressed and analysed using GIS techniques. Second, based on GIS model and distribution patterns ground-dwelling beetles diversity,we will carry out some studies as fallows:（1）Ground-dwelling beetles diversity distribution pattern with elevation and their origin；（2）Affect of aspect and slope and their interactions on ground-dwelling beetles diversity ;（3）Coupling relationship between beetles diversity and topographical and edaphic factors. On the basis of former research, we will predict and validate of the spatial distribution of diversity of ground-dwelling beetles on a greater scale in Helan Mountain in order to interpretate affect of azonality environmental factors on ground-dwelling beetles diversity distribution pattern.

贺兰山是我国重要生物多样性中心之一——阿拉善-鄂尔多斯中心的核心区域，研究该地区生物多样性分布格局及其形成机制具有重要的保护生物学意义。地表甲虫对生境的变化极为敏感，具有广谱的生物地理学和生物学探针的功能，其物种的组成及数量变化可作为环境变化和生物多样性变化的重要指标。项目以系统野外调查为基础，结合遥感影像（RS）和数字高程模型（DEM），利用GIS划分垂直植被带、提取不同地形条件下垂直带与生态因子特征、对垂直带的地形分异规律进行图谱表达与分析，研究地表甲虫多样性海拔梯度格局及其成因，分析坡度、坡向及二者交互作用对地表甲虫丰富度和多样性的影响，探索在小尺度下地形对地表甲虫多样性的作用机制，阐明地表甲虫多样性与土壤、地形因子的耦合关系，预测地表甲虫多样性空间分布并进行验证，以期对贺兰山地表甲虫多样性分布格局及非地带性环境因子的作用机制做出科学解答。

本项目揭示了贺兰山地表甲虫区域尺度水平空间分布和山地垂直带分布格局的特点，及其与环境因子的相关性，分析了冲积扇荒漠景观地表甲虫多样性小尺度空间分布格局及优势类群种间关系。(1)地表甲虫(31科252属469种)物种丰富度水平空间分布以贺兰山中段最高，南段比北段高，西坡比东坡高，可分为北段强旱生景观甲虫地理群，中西段半湿生景观甲虫地理群，中东段及南段半旱生景观甲虫地理群3个地理群。年均温和年均降水量是影响最显著的因子。水分和能量因子是甲虫水平空间分布格局的主导因子，生境异质性有助于提高甲虫物种丰富度。气候因素与生境异质性对不同优势科物种丰富度的相对影响并不一致。在贺兰山的南段和北段，生境异质性和水分因子对甲虫物种丰富度影响作用明显。(2)甲虫物种丰富度随海拔梯度呈现不对称的单峰格局，在接近海拔中段范围(1800-2200m)具有较高的物种丰富度。最冷月平均气温是甲虫垂直分布的最显著因子，即能量因子决定甲虫物种丰富度垂直分布格局。拟步甲科和象甲科昆虫物种丰富度格局随海拔梯度略呈现单调递减格局，步甲科、金龟科、天牛科和瓢虫科昆虫物种丰富度格局随海拔梯度略呈现不对称的单峰格局。贺兰山垂直植被带的灰榆疏林带地表甲虫群落科丰富度和活动密度最高，旱生落叶灌丛带Shannon-Wiener多样性指数和Margalef丰富度指数最高，典型草原带Simpson优势度指数最高。海拔、土壤含水量和枯落物盖度明显影响地表甲虫群落多样性；在较小空间尺度，地形因子对地表甲虫分布相对重要。(3)贺兰山冲积扇荒漠景观小尺度地表甲虫优势种空间自相关性和群落空间异质性具有明显的季节波动性，夏季群落空间格局比较简单；优势种物种间大多表现为正空间关联性，且主要受结构性因素单一调控；地表甲虫群落在所有月份均处于不稳定状态，但群落组成随季节演替时序分明，表现了较强的恢复力。项目成果为理解环境因子对贺兰山山地地表甲虫生物多样性形成及山地生态系统稳定性的维持机制具有重要意义。