Soil legacy effects and plant-soil feedback contribution to secondary succession processes

Secondary succession is the process by which a community develops into a climax community over time.However,knowledge on the mechanisms,relating to soil legacy effects(soil chemistry and enzyme activity)and plant-soil feedback(PSF),driving community succession remains limited.In this work,we examined the PSF associated with three succession stage species through a 2-year greenhouse experiment.Setaria viridis,Stipa bungeana,and Bothriochloa ischemum were selected to represent dominant and representative early-,mid-,and late-successional stage species,respectively,of semiarid grasslands on the Loess Plateau.In response to the different soil origin,the shoot biomass of early-,mid-,and late-species were all higher when grown in their own soil than in other species’soils,which indicated that the PSF of three species were positive.Over two growth periods,the early-species experienced a negative PSF,but the mid-and late-species experienced negative,neutral and positive PSF in the soil of early-,mid-and late-species,respectively.Our study demonstrates that soil legacy effects and PSF have a significant impact on community succession processes.

Negative legacy effects of rainfall and nitrogen amendment on leaf lifespan of steppe species

Aims Studying legacy effects(i.e.the indirect effect that persists for a period after casual factors cease)can provide novel insights into the role of ecological drivers.Leaf lifespan is among the key traits with multi-level functions.It is clear about the direct effects of water and nitrogen(N)amendment on leaf lifespan,but it remains unclear about their legacy effects on leaf lifespan and the associated mechanisms.Methods We performed a five-year field experiment with supplemental water and N,and quantified the legacy effects of field water and N addi-tion on the leaf lifespan,length and growth rate of four dominant species,Agropyron cristatum,Cleistogenes squarrosa,Leymus chin-ensis and Stipa grandis in a temperate steppe.Important Findings Across all the species,the legacies of water and N addition increased their leaf length and growth rate directly but decreased their leaf lifespan through direct and indirect pathways.Leaf lifes-pan was positively linked with leaf length but negatively associ-ated to leaf growth rate.the legacy effect of water addition on leaf lifespan was greater than that of N addition.Field N addition induced soil acidification and eutrophication,as well as altered soil microbes,but only eutrophication had negative legacy effects on leaf lifespan.these findings provide substantial evidence that rainfall and N amendment have negative legacy effects on leaf lifespan,and also highlight that multiple mechanisms or pathways determine legacy effects.Additionally,our results suggest that field water and N manipulations may influence the other leaf traits and functions.