Open AccessGrazing weakens temporal stabilizing effects of diversity in the Eurasian steppe
Author(s) -
Ren Haiyan,
Taube Friedhelm,
Stein Claudia,
Zhang Yingjun,
Bai Yongfei,
Hu Shuijin
Publication year - 2018
Publication title -
ecology and evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.17
H-Index - 63
ISSN - 2045-7758
DOI - 10.1002/ece3.3669
Subject(s) - grazing , ecosystem , steppe , conservation grazing , biomass (ecology) , species richness , ecology , ecological stability , environmental science , agronomy , productivity , biology , abundance (ecology) , economics , macroeconomics
Many biodiversity experiments have demonstrated that plant diversity can stabilize productivity in experimental grasslands. However, less is known about how diversity–stability relationships are mediated by grazing. Grazing is known for causing species losses, but its effects on plant functional groups ( PFG s) composition and species asynchrony, which are closely correlated with ecosystem stability, remain unclear. We conducted a six‐year grazing experiment in a semi‐arid steppe, using seven levels of grazing intensity (0, 1.5, 3.0, 4.5, 6.0, 7.5, and 9.0 sheep per hectare) and two grazing systems (i.e., a traditional, continuous grazing system during the growing period ( TGS ), and a mixed one rotating grazing and mowing annually ( MGS )), to examine the effects of grazing system and grazing intensity on the abundance and composition of PFG s and diversity–stability relationships. Ecosystem stability was similar between mixed and continuous grazing treatments. However, within the two grazing systems, stability was maintained through different pathways, that is, along with grazing intensity, persistence biomass variations in MGS , and compensatory interactions of PFG s in their biomass variations in TGS . Ecosystem temporal stability was not decreased by species loss but rather remain unchanged by the strong compensatory effects between PFG s, or a higher grazing‐induced decrease in species asynchrony at higher diversity, and a higher grazing‐induced increase in the temporal variation of productivity in diverse communities. Ecosystem stability of aboveground net primary production was not related to species richness in both grazing systems. High grazing intensity weakened the temporal stabilizing effects of diversity in this semi‐arid grassland. Our results demonstrate that the productivity of dominant PFG s is more important than species richness for maximizing stability in this system. This study distinguishes grazing intensity and grazing system from diversity effects on the temporal stability, highlighting the need to better understand how grazing regulates ecosystem stability, plant diversity, and their synergic relationships.