Life Zone Ecology of the Bhutan Himaraya III

研究了不丹生命带在海拔1000-3500ma.s.l范围内的临床地貌、地貌和生态特征的海拔格局。1999-2001年间。数据记录器记录了1999年9月至2001年8月沿曾珠一带的温度和湿度状况，并获得了完整的全年数据。在0.57-0.62C/100m的范围内，温度递减率随测量地点的地形情况而变化。旱季(4月)的递减率较大，季风雨季的递减率较小，反映了相对湿度。群众运动在不丹喜马拉雅非常活跃。滑坡是通过在变质岩下的地区的层面上剪切而发生的。随之而来的是，河道沿层面倾角方向移动，发育了不对称的山谷。研究了沿高山系列的植被分带，包括Gasa系列、Lobesa系列和Seagor-Lingmetang系列。GASA系列主要集中在每个生命带内的地形变化，LOBESA系列从干燥的谷底到潮湿的山脊云雾林具有明显的地带性。从温暖/干燥的刺松林、中纬度的灰皮栎林/Q.Lanata林、白栎林/半果叶栎林，以及海拔2700米以上的水杉林和冷杉林。不丹三分之一的农田被维持轮作耕作，这些地点因其在休闲期的次生演替而引人注目。不丹有两种轮耕方式，即5年休耕的草地休耕(庞兴)和12年休耕的森林休耕(Tseri)。对于前者，我们在Bumthang做到了，而对于后者，我们在Shemang，这两个地方都是两种轮作的主要区域。在这两个地点，我们分析了植被演替和土壤发育，并找到了系统可持续管理的关键条件。

Altitudinal patterns in clhimatologjcal, geomorphological, and ecological features of the Bhutanese life-zones were studied in a range of c. 1000-3500 m a.s.l. during 1999-2001. Temperature and moisture conditions were recorded in data loggers and obtained complete year round data from September 1999 to August 2001 along Tsang Chu. Temperature lapse rate was varied by the topographical situation of the measuring sites in a range of 0.57-0.62 C/100m. The lapse rate is larger in dry season (April) and smaller in monsoon rain season reflecting relative humidity. Mass movement is extremely active in the Bhutan Himalaya. Land slides took place by shearing on a bedding plane in the area underlain by metamorphic rocks. As the consequences river channels shift in the dip direction of the bedding plane and asymmetric valleys have developed. Vegetation zonation along altihidinal series were studied along Gasa series, Lobesa series, and Seagor-Lingmethang series. Gasa series mainly focused on topographical diversification within each life zone, Lobesa series had clear zonation from dry valley bottom to humid mountain cloud forests on ridges. From warm/dry Pinus roxburghii forests, mid-altitudinal Quercus griffithii/Q. lanata forests, Quercus glauca /Q. semecarpifolia forests, and Isuga dumosa forests and Abies densa forests above 2700 m. One third of the Bhutanese agricultural fields are maintained as shifting cultivation, and the sites are interesting for their secondary succession during fallow periods. There are two types of shifting cultivation in Bhutan, grass fallow (pangshing) of five year fallow and forest fallow (tseri) of 12 year fallow periods. For the former, we did in Bumthang, and for the latter in Shemgang, both place are the major area for both each types of shifting cultivation. In both sites we analyzed vegetation succession and soil developments, and found critical conditions for the sustainable managements for the system.