新疆东部天山蝶类多样性及其垂直分布

2006-2008年研究了新疆东部天山蝶类多样性和垂直分布.结果表明:研究区域内共记录蝴蝶7科43属63种,占新疆已记录蝶类种数的24.80％,区系组成主要是古北种,占73％；其次是广布种,占27％,没有发现东洋种.其中蛱蝶科的物种数最多,为11属19种,蚬蝶科的物种数最少,只有1属1种.按海拔将生境分为5个垂直自然带,包括低山灌木草原带、山地森林草原带、亚高山草甸带、高山草甸带、垫状植被带.蝶类物种数和个体数排序为亚高山草甸带＞山地森林草原带＞低山灌木草原带＞高山草甸带＞垫状植被带.采用Shannon-Wiener指数和G-F指数对蝶类物种和科、属的多样性进行了分析评价,结果显示亚高山草甸带的蝶类多样性最为丰富,其次是山地森林草原带和低山灌木草原带,而高山草甸带和垫状植被带的蝶类多样性相对较低,物种和科、属多样性分析结果均一致.蝶类垂直分布明显,物种数和个体数随海拔变化的趋势类似,均为先增加后下降.蝶类区系成分随着海拔升高发生改变,广布种的比例逐渐降低,高山草甸带和垫状植被带只有古北种分布.研究结果显示,生境改变对蝴蝶群落影响明显,保护生境是保护蝴蝶生存的最主要措施.

Butterfly diversity and vertical distribution in eastern Tianshan Mountain in Xinjiang

The Tianshan Mountain area is a large system of mountain ranges that spans China and a number of other Central Asian countries, with a length of more than 1700 km within the Xinjiang Uyghur Autonomous Region, northwest China. It has a typical temperate continental climate, has abundant forest and grassland resources, and is one of the most important water sources in the arid region of Central Asia. The Tianshan Mountains are also considered a biodiversity hotspot that plays a key role in the function of regional ecosystems, providing various habitats for plants and animals, including butterflies, which are considered environmentally sensitive and thus have potential to be used as ecological indicators. Surveys in the Xinjiang eastern Tianshan Mountains from 2006 to 2008 recorded 63 species of butterflies, which belonged to seven families and 43 genera, accounting for 24.80% of the total butterfly species recorded in Xinjiang. Palearctic species were dominant (73%), while widely distributed species made up the rest of the species (27%). No oriental species were recorded because of the geographical isolation. The Nymphalidae were the most diverse group with 19 species and 11 genera, while only 1 species of Riodinidae was recorded. The butterfly habitats in the Xinjiang eastern Tianshan Mountain area were divided into 5 altitudinal zones, including low mountain shrub grassland, mountain forest steppe, subalpine meadow, alpine meadow, and the cushion vegetation zone. In terms of butterfly species richness and total butterfly abundance these habitat zones were ranked from highest to lowest as follows: subalpine meadow > mountain forest steppe > low mountain shrub grassland > alpine meadow > cushion vegetation zone. The diversity of butterfly species, genera, and families were comprehensively evaluated using the Shannon-Wiener index and the G-F index. The results indicated that subalpine meadow habitats had the highest species diversity, followed by mountain forest steppe, low mountain shrub grassland, alpine meadow habitats, and finally the cushion vegetation zone. The Shannon and G-F indices showed similar patterns, demonstrating high species evenness among habitats and similar distribution patterns of butterfly families, genera, and species diversity in the study area. Changes in the number of species and butterfly abundance were related to changes in altitude, initially increasing with altitude and then declining. The fauna composition also changed along the altitudinal gradient. The proportion of widely distributed species gradually declined, and there was no distribution especially in meadow and cushion vegetation zone. However, Palearctic species showed an opposite trend, rising with increasing altitude. Our results indicate that butterfly communities in the eastern Tianshan Mountain area were different from those at Altai Mountain and two other parts of the Tianshan Mountain area. Both diversity and fauna composition were strongly affected by different types of habitats. Attention should be paid to the potential consequences of habitat loss on butterflies that are only distributed in the cushion vegetation and alpine meadow zones. These species and habitats are particularly vulnerable as temperatures are expected to rise by a greater amount at higher altitudes in the future, which could cause the snowline to rise. To avoid the irreversible loss of biodiversity, habitat protection should be considered fundamental for the conservation of butterflies, and particularly the preservation of higher altitude habitats.