The Relationship Between Plant Diversity And Climate Factors In Different Grassland Types Of Xinjiang

Xinjiang mountain grassland not only provides high quality forage for traditional animal husbandry, but also maintains the stability of fragile ecological environment in the whole region. So, it is important to study the distribution characteristics of plant diversity, and its relationship with biological(productivity) and abiotic factors(climate) for deeply understanding of the distribution pattern and role of Xinjiang mainly grassland. Our research based on seven grassland types, investigated plant diversity, aboveground net primary production and collected climate factors in 364 field sites, focus on solving the following three issues:(1) The distribution characteristics of plant in different grassland types and region;(2) The relationship of productivity to species Richness in the Xinjiang temperate grassland;(3) The response of species richness to climate factors in different grassland types of Xinjiang. The main results were shown as follows:Firstly, herb plant add up 132 genuses of 38 familie, shrub plant add up 41 genuses of 15 familie in Xinjiang grassland; Low plain meadow add up 19 genuses of 9 familie, shrub add up 16 genuses of 9 familie; Alpine steppe add up 26 genuses of 17 familie, Temperate meadow steppe add up 43 genuses of 20 familie, shrub add up 3 genuses of 3 familie; Temperate steppe desert add up 39 genuses of 15 familie, shrub add up 17 genuses of 8 familie; Temperate steppe add up 75 genuses of 28 familie, shrub add up 7 genuses of 6 familie; Temperate desert steppe add up 59 genuses of 21 familie, shrub add up 17 genuses of 9 familie; Temperate desert add up 60 genuses of 20 familie, shrub add up 34 genuses of 12 familie.Secondly, Gramineae is the biggest dominant family and Stipa is the biggest dominant genus in herb plant of Xinjiang grassland. Then, Compositae is the second dominant family and Seriphidium is the second dominant genus. In the shrub, Chenopodiaceae is the biggest dominant family and Caragana is the biggest dominant genus, Leguminosae is the second dominant family and Reaumuria is the second dominant genus. The species richness changes cross different grassland types(from high to low), temperate meadow steppe(7.73), temperate steppe(5.04), alpine steppe(4.36), temperate desert steppe(3.99), temperate steppe desert(3.02), temperate desert(2.08), low plain meadow(1.43).Thirdly, the species composition of grassland in different regions is very different, the dominant plant is Gramineae Stipa, Compositae Seriphidium and Chenopodiaceae Krascheninnikovia in Altay region. In the Tacheng region, dominant plant is Gramineae Festuca and Stipa, Leguminosae Caragana. And the dominant plant is Cyperaceae Carex and Compositae Seriphidium in Yili region. In the north of Tianshan, dominant plant is Gramineae Stipa, Compositae Seriphidium and Tamaricaceae Reaumuria. And In the south of Tianshan, the dominant plant is Gramineae Stipa and Agropyron, Leguminosae Caragana. The dominant plant is Gramineae Stipa, Compositae Seriphidium, Tamaricaceae Tamarix and Reaumuria in Kunlun Mountains.Fourthly, a positive linear relationship was detected between ? diversity and ANPP for MS and DS, while a unimodal alpha diversity-ANPP relationship was found for TS. No significant relationship was found between alpha diversity and coefficient variation ANPP. Within each vegetation type, no significant relationship was found between beta diversity and ANPP, however, beta diversity exhibited a positive linear or quadratic relationship with the coefficient of variation of ANPP. Our results demonstrated that in Xinjiang temperate grasslands, ANPP was mainly controlled by ? diversity while the coefficient of variation of ANPP was most explained by ? diversity.Fifthly, in Xinjiang grassland, temperate steppe, SR was positively and linearly related with MAP, but unimodal related with MAT and altitude. In alpine steppe and low plain meadow, SR was positively and linearly related with MAP and negatively related with MAT, but SR decreased at the beginning and then increased with altitude. In temperate desert steppe, SR was significantly positive related with MAP; In alpine steppe and low plain meadow SR was positively and linearly related with MAP and negatively related with MAT, but unimodal related with altitude. Therefore, the water thermal factor is the main determinant of the formation of the Xinjiang grasslands.