内蒙古地区不同景观植被地带蝗总科生态区系的区域性分异

Regional differentiation of the Acridoidea ecofaunas in different vegetational zones (subzones) of Inner Mongolia region

为了阐明内蒙古地区不同景观植被地带蝗总科生态区系(Acridoidea ecofaunas)的生态地理学特征,本文依据长期野外考察和文献积累数据,分别对寒温型明亮针叶林带(F1)、中温型夏绿阔叶林带(F2)、森林草原带(FS)、典型草原带(TS)、荒漠草原带(DS)、暖温型草原化荒漠亚带(SD)和典型荒漠亚带(TD)等7个不同类型植被地带(或亚带)内蝗总科区系结构组成、生态生存条件(植被、气候、土壤等)及其区系形成的生态学机理进行了分析,综合比较了各植被地带(或亚带)的蝗虫物种多样性、区系地理成分的区域性分异及其与地带间不同植被的相关性。结论指出,由于多数蝗种具有以禾本科(Gramineae)和菊科(Compositae)植物为主要食料的食性特征,而典型草原带的植被群落恰以"多年生丛生禾草及根茎禾草"为建群优势层片,其形成的丰富食物资源、多样的栖息场所、充足的日光辐射和较长的生长期以及有利于产卵孵化的土壤条件等,为蝗虫提供了最为多样的时间、空间和营养生态位(niches),故蝗虫长期受自然选择的压力,在适应协同进化的历史过程中,形成了它们在典型草原带内具有最高的物种多样性。相比之下,在具有极端生态生存条件的内蒙古东部针叶林带和西部典型荒漠亚带内,分别因其低温高湿和高温低湿的两类不同极端气候特征的生态作用,形成了蝗虫在这两个植被地带内生存分布的生态阻限,故其拥有的物种多样性水平最低,其区系结构的组成种类也截然不同。

Based on the data of long-term field surveys and various literature records, the ecofaunas of Acridoidea in the following seven vegetational zones （or subzones） of Inner Mongolia region of China were expounded： Bright coniferous forest zone of cold-temperate type （F1）, Deciduous broad-leaf forest zone of mid-temperate type （F2）, Forest steppe zone （FS）, Typical steppe zone （TS）, Desert steppe zone （DS）, Steppe desert subzone of warm-temperate type （SD） and Typical desert subzone of warm-temperate type （TD）. The zonal characteristics of specific compositions of Acridoidea fauna, the ecological conditions （vegetation, climate and soil etc. ） in each zone, and the ecological mechanisms in formation of these different specific compositions were analyzed. The species diversities of acridoids and the zonal diversification of faunal geographic elements in different zones, and their relationships with different vegetation in each zone were also summarized and compared. The results indicated that the TS sustained the highest species diversity of acridoids since it could supply acridoids with sufficient temporal, spatial and trophic niches. In food selection acridoids favor mostly plants of Gramineae and Compositae, and both the ＂perennating rosette grass＂ and ＂root stock grass＂ were just right the dominant components of plant communities in the TS, and then the acridoids in this zone could get the most diverse temporal, spatial and nutritional niches with rich foods, diverse habitats, abundant sunshine and suitable soil for egg laying. In contrast, the two vegetational zones of F1 and TD in Inner Mongolia Region all possessed relatively lower species diversity and quite different compositions of acridoids. And this may be caused by the extreme climatic conditions （lower temperature with high humidity in F1 and high temperature with lower humidity in TD） that restricted the occurrence and distribution of acridoids in both zones. It is inferred that the modem status of the acridoid ecofaunas in Inner Mongolia Region is the combined result of both natural selective stress to acridoids and their adaptive evolution in the long course of natural history.