J Plant Ecol ›› 2020, Vol. 13 ›› Issue (5): 611-620.DOI: 10.1093/jpe/rtaa046

• Research Articles • Previous Articles     Next Articles

Resource enrichment combined with biomass removal maintains plant diversity and community stability in a long-term grazed grassland

Feng-Wei Xu1, *, Jian-Jun Li2 , Li-Ji Wu3 , Xiao-Ming Lu1 , Wen Xing4 , Di-Ma Chen5, , Biao Zhu6 , Shao-Peng Wang6 , Lin Jiang7 and Yong-Fei Bai1,8, *   

  1. 1 State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China, 2 Collaborative Innovation Center of Jiangxi Typical Trees Cultivation and Utilization, College of Forestry, Jiangxi Agricultural University, Nanchang 330045, China, 3 College of Ecology and Environmental Science, Inner Mongolia Agricultural University, Hohhot 010011, China, 4 Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China, 5 College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang 443002, China, 6 Department of Ecology, College of Urban and Environmental Science, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China, 7 School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA, 8 College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China

    *Corresponding author. E-mail: xufengwei@ibcas.ac.cn (F.-W.X.); yfbai@ibcas.ac.cn (Y.-F.B.)
  • Received:2020-06-16 Revised:2020-06-28 Accepted:2020-07-16 Online:2020-07-21 Published:2020-10-01

Abstract:

Aims

Long-term heavy grazing reduces plant diversity and ecosystem function by intensifying nitrogen (N) and water limitation. In contrast, the absence of biomass removal can cause species loss by elevating light competition and weakening community stability, which is exacerbated by N and water enrichment. Hence, how to maintain species diversity and community stability is still a huge challenge for sustainable management of worldwide grasslands.

Methods

We conducted a 4-year manipulated experiment in six long-term grazing blocks to explore combination of resource additions and biomass removal (increased water, N and light availability) on species richness and community stability in semiarid grasslands of Inner Mongolia, China.

Important Findings

In all blocks treated with the combination of resource additions and biomass removal, primary productivity increased and species richness and community stability were maintained over 4 years of experiment. At both species and plant functional group (PFG) levels, the aboveground biomass of treated plants remained temporally stable in treatments with the combination of N and/or water addition and biomass removal. The maintenance of species richness was primarily caused by the biomass removal, which could increase the amount of light exposure for grasses under resource enrichment. Both species asynchrony and stability of PFGs contributed to the high temporal stability observed in these communities. Our results indicate that management practices of combined resource enrichment with biomass removal, such as grazing or mowing, could not only enhance primary productivity but also maintain plant species diversity, species asynchrony and community stability. Furthermore, as overgrazing-induced degradation and resource enrichment-induced biodiversity loss continue to be major problems worldwide, our findings have important implications for adaptive management in semiarid grasslands and beyond.

Key words: biomass removal, resource addition, species richness, community stability, plant functional groups (PFGs), species asynchrony

摘要:
长期重度放牧通过加剧水氮限制减少植物多样性与生态系统功能。相反,缺乏放牧干扰(生物量移除)会通过增加光竞争减少物种多样性,从而弱化生态系统稳定性,而这一过程会由于资源富集而加剧。因此,如何维持物种多样性和群落稳定性仍然是世界草原可持续管理的一大挑战。在本研究中,我们在中国内蒙古3个放牧强度的长期实验样地设置了为期4年的控制实验,来探究结合资源添加与生物量移除(同时增加水、氮和光的有效性)对物种丰富度与群落稳定性的影响。研究结果表明,在4年资源添加结合生物量移除处理下,群落初级 生产力增加,同时物种丰富度与群落稳定性能够维持。在物种与功能群水平上,地上生产力能够保持时间稳定性。物种丰富度维持的主要 原因是:在资源富集的情况下,生物量移除能够增加光的有效性。物种异步性与功能群稳定性有助于群落稳定性维持。我们的研究结果表 明,资源添加与生物量移除结合的管理方式,不仅能够增加草地初级生产力,而且能维持其物种多样性、异步性与群落稳定性。在世界范 围内,长期放牧导致的草原退化与资源富集引起的其生物多样性丧失仍将是人类面临的主要生态问题,我们的研究结果对于半干旱草原以 及其它草原的适应性管理具有重要的意义。

关键词: 生物量移除, 资源添加, 物种丰富度, 群落稳定性, 植物功能群, 物种异步性