Acta Geographica Sinica ›› 2020, Vol. 75 ›› Issue (5): 931-948.doi: 10.11821/dlxb202005004

• Land Cover Change and Ecosystem Services • Previous Articles     Next Articles

Vertical variation of land cover in the Central Himalayas

ZHANG Yili1,2,3, WU Xue1,3, ZHENG Du1   

  1. 1.Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
    2.CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China
    3.University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-10-10 Revised:2020-01-07 Online:2020-05-25 Published:2020-07-25
  • Supported by:
    National Nature Sciences Foundation of China(41761144081);Strategic Priority Research Program of Chinese Academy of Sciences(XDA20040201);The Second Tibetan Plateau Scientific Expedition and Research(2019QZKK0603)

Abstract:

The Qomolangma Mountain region within the Central Himalayas is characterized by obvious altitudinal variation, habitat complexity, and land cover diversity. This region is therefore one of the most sensitive areas to climate change in the world. Besides, because this region has the most complete natural vertical spectrum in the world, it is ideal for studying the vertical structure of alpine land cover. Utilizing land cover data for 2010 (30 m resolution) along with digital elevation model outputs, three division methods were defined that encompass the northern and southern slopes of Qomolangma Mountain. These comprised the ridgeline method, the sample transect method, and the sector method. The study investigated altitudinal distributions, similarities and differences, and changes in the degree of land cover on the northern and southern slopes of the Himalayas area using the software ArcGIS and MATLAB tools and division models. The main results of this analysis are listed as follows:
Firstly, the distribution of land cover in mountainous areas was characterized by an obvious vertical spectrum structure, with the south-six and north-four pattern of vertical spectrum of land cover in the Central Himalayas marked by the influence of human activities. Secondly, zonal distribution was exhibited by forests, grasslands, sparse vegetation, barren land, glaciers, and snow covers from low to high altitudes. It was markedly different in the composition and structure of land cover vertical spectrum between the northern and southern slopes of this mountain area. The vertical spectrum of land cover types on the southern slope was complete and diverse, but it was relatively simple on the northern slope. The study shows that given the same land cover type, the amplitude of elevation distribution on the southern slope was wide, while that on the northern slope was narrow. The distribution of land cover types on the southern slope was low. Thirdly, the results show that the area distribution ratio of each land cover type varied with elevation according to change mode. Vertical distribution patterns of land cover types on the southern and northern slopes were therefore divided into four categories, with glaciers, snow, sparse vegetation, and grasslands conforming to unimodal distribution patterns. The bare land also followed a unimodal distribution pattern on the southern slope, but it followed a bimodal one on the northern slope. Fourthly, all kinds of vertical belt structures and land cover divisions on the southern slope were similar, but they were different from one another on the northern slope due to division methods. In comparison with field survey data, results reported here for the sector method were more in line with the actual situation.

Key words: land cover, altitudinal zonation, Central Himalayas, Mt. Qomolangma, Mt. Makalu, Mt. Cho Oyu