Chin J Plant Ecol ›› 2013, Vol. 37 ›› Issue (7): 620-630.DOI: 10.3724/SP.J.1258.2013.00064

• Research Articles • Previous Articles     Next Articles

Relationship of ecosystem primary productivity to species diversity and functional group diversity: evidence from Stipa breviflora grassland in Nei Mongol

MA Wen-Jing1,ZHANG Qing1,2,*(),NIU Jian-Ming1,2,KANG Sarula1,LIU Peng-Tao3,HE Xin1,YANG Yan1,ZHANG Yan-Nan1,WU Jian-Guo2,4   

  1. 1College of Life Sciences, Inner Mongolia University, Hohhot 010021, China
    2Sino-US Center for Conservation, Energy and Sustainability Science in Inner Mongolia, Hohhot 010021, China
    3Inner Mongolia Meteorology Bureau, Hohhot 010051, China
  • Received:2013-01-04 Accepted:2013-05-03 Online:2013-07-01 Published:2013-07-05
  • Contact: ZHANG Qing

Abstract:

Aims The relationship between biodiversity and ecosystem functioning has been a central issue in ecology. However, this relationship is poorly understood for the Stipa breviflora grassland, which is a major community type of desert steppe in Nei Mongol. With unpredictably fluctuating climate conditions, these desert steppe ecosystems are fragile and provide a unique opportunity to test our current understanding of the relationship between biodiversity and ecosystem functioning. This study has two objectives: (1) to examine if species diversity and functional group diversity affect ecosystem primary productivity in the desert steppe of Nei Mongol and (2) to explore how resource supply levels affect the relationship between diversity and productivity.
Methods Based on life forms, species were classified into five functional groups: shrub and semishrub, perennial bunchgrass, perennial rhizome grass, perennial forb, and annual and biennial. Species richness and functional group richness were used to represent species diversity and functional group diversity, respectively. Based on the dryness coefficient, 202 sites across the S. breviflora grassland in Nei Mongol were sampled, and divided into two resource supply levels: arid and semiarid zones. In order to tease out the effect of precipitation, partial regression analysis and partial correlation analysis were used for exploring the relationship of ecosystem primary productivity to species richness and functional group richness, respectively. According to the determination coefficient of regression analysis, the effect of resource supply levels on the diversity-productivity relationship was evaluated.
Important findings Species richness and ecosystem primary productivity were both positively and linearly correlated with precipitation, but no significant correlation was found between functional group richness and precipitation. Ecosystem primary productivity increased significantly with species richness, but not with functional group richness. Resource supply levels could affect the diversity-productivity relationship in that plant species diversity generally had a weaker effect on ecosystem primary productivity at the lower resource supply level and a stronger effect at the higher resource supply level.

Key words: functional group richness, productivity, resource supply, species richness