Effects Of Warming On Litter Decomposition And Bacteria Community In An Artemisia Ordosica Shrub Ecosystem In The Mu Us Desert

Climate warming profoundly affects the structure and function of terrestrial ecosystems.Litter decomposition is a key process of the matter cycle of the ecosystem,which regulate the release of CO2 at ecosystem level,the formation of organic matters,and the enrichment of nutrients.In addition,soil microorganisms play a crucial role in this matter cycle of ecosystem.Understanding the litter decomposition and soil microbial community composition in response to warming in arid and semi-arid regions is essential for accurately predicting the carbon cycle in this region under climate change,due to these areas act as regulatory role in carbon cycle at regional and global scale.In this study,we performed experiments in the Mu Us Desert,to explore the effect of climate warming on litter decomposition of two species,Leymus secalinus and Artemisia ordosica,and microbial community of litter.We choose the leaf and twig of A.ordosica(AL and AT hereafter),and leaf of L.secalinus(LS hereafter)as decomposed matters.Open top chamber(OTC)was used to increase surface soil temperature.We found that,1)The rate of mass remaining for AL,AT,and LS were 48.63%?81.53%?64.88%respectively in natural conditions,and 58.67%,88.23%and 74.77%respectively in warming treatment,suggesting that climate warming slowed the rate of mass loss of litter(P<0.01).2)The litter mass loss rate was significantly affected by decomposition duration,the type of litter,and warming(all P<0.01).Moreover,different type of litter decomposition responded differently to climate warming(significant warming x litter type effect,P<0.01),For one type of litter,the inhibited effect of warming changed with time(significant warming x time effect,P<0.01).Additionally,in the same environmental conditions,the mass loss rate of different litter types changed differently with duration(significant time × litter type effect,P<0.01)3)Warming significantly decreased the diversity of bacterial community of AL(Shannon index:P<0.05,ACE index:P<0.01).However,diversity of bacterial community of AT(Shannon index:P=0.99,ACE index:P=0.38)and LS(Shannon index:P=0.12,ACE index:P=0.24)were not affect by warming.Moreover,climate warming alerted the relative abundance of dominant bacteria at phylum and genus level.Our results showed that climate warming could inhibit the decomposition rate of litter of A.ordosica community in Mu Us Desert,and slow the turnover rate of carbon and nutrient elements in this ecosystem.Warming had no effect on the bacterial diversity of the litter(except the A.ordosica leaf litter),but changed the relative abundance of dominant bacteria.Moreover,our study revealed the litter decomposition pattern of A.ordosica community in the temperature-increasing condition and the response mechanism of microbial community composition of the litter.Additionally,these findings can explain the litter decomposition in response to climate warming from the view of microbial community composition.