Universal rule and regional variation of vegetation height assembly of typical grasslands in China

Abstract

Measuring plant heights one by one is an important way to explore the height structure of grassland plant communities, and can be used to analyze the universal rules and regional variations of vegetation growth under environmental change. We chose grasslands in three plateaus, namely Tibetan Plateau (TP), Mongolian Plateau (MP) and Loess Plateau (LP), and set up three grassland transects along the precipitation gradients from meadow, steppe to desert. The mean height of grassland vegetation is 30.38 ± 22.44 cm, and the mean height from TP, MP to LP increases significantly. The aggregation of grassland vegetation presents a positive skew distribution (0.91, 3.60), and the community aggregation from TP, MP to LP tends to a normal distribution (0, 3). However, for TP, there is an exponential distribution in community aggregation of meadows, and a uniform distribution in that of desert. The explanatory effect of climate and soil nutrients on the variation of mean height in each region is more than 70%, while the explanatory effect on the community aggregation is the highest at TP, only 29%. From TP, MP to LP, response intensity of mean height to environmental changes increased significantly, and the influence of temperature and precipitation gradually increased, the influence of radiation, wind speed, and nutrients gradually weakened, and the synergy among environmental factors strengthened. Our study shows that normal distribution is a universal rule of grassland height construction, and the synergy of environmental factors varies from region to region.

Latitudinal differentiation and patterns of temperate and subtropical plants in the Qinling-Daba Mountains

“…Subsequent researchers used more stable climate indicators such as the number of days with an average daily temperature ≥ 10℃ (Zheng et al, 2008), the warm index (Hong and Li, 1981;Fang, 1991;2001), the cold index (Hong and Li, 1981), mountain altitudinal belt spectrum, vegetation type, and floral community, to determine the boundary between warm temperate and northern subtropical zones. Several dividing lines have been proposed, including the northern slope of the Qinling Mountains (Huang, 1959;Kuang et al, 1961;Hou, 1963;1964), the main ridge line (Zhu, 1958;Wu and Hou, 1980;Liu, 1981), the southern slope of the Qinling Mountains (Qian et al, 1956;Zhang and Cui, 1963;Zhou, 1965;Zhang and Zhang, 1979;Zhang, 1981;Lei, 1999;Kang and Zhu, 2007;Wang et al, 2010), the Daba Mountains (Fang, 1991;Zhao et al, 2020), and the Yangtze River (EBAGS, 1959;Ying et al, 1990;Song, 1999;Fang, 2001). Most vegetation and climate data used in these studies were obtained before the 1980s or 1990s and were fragmented.…”