A metagenomic survey of soil microbial communities in old fields dominated by exotic plant species and native remnant grasslands in the Inland Pampa, Argentina

XIMENA LÓPEZ ZIEHER; VIVANCO LUCIA; LAURA YAHDJIAN

Baltimore

Congreso; 100th Annual Meeting of the Ecological Society of America; 2015

Ecological Society of America

Background/Question/MethodsThe reassembly of plant communities in old fields with strong cultivation legacy frequently leads to theestablishment of exotic plant species. Such systems show little recovery towards native grasslands and mayrepresent novel ecosystems. We hypothesize that exotic plant invasions produce shifts in soil microbialcomposition which might facilitate the persistence of a degraded vegetation state. Also, we expect bacterialcommunities from old fields to be homogenous owing to the fact that plant communities in successionalgrasslands are highly dominated by one or few species. By contrast, soil bacterial communities from naturalremnants would show higher differences among sites. We used 454 pyrosequencing of the 16s rRNA gene tocharacterise and compare soil microbial communities of 5 exoticdominatedold fields and 5 native grasslandremnants of the Inland Pampa, Argentina.Results/ConclusionsWe found that Acidobacteria and Planctomycetes were the most abundant bacterial phyla in these grasslands,accounting for 50% of sequences. The relative abundance of certain bacterial groups differed between old fieldsand native grasslands (Plactomycetes, Verrucomicrobia, and Chloroflexi were more abundant in old fields,whereas Nitrospirae was more abundant in remnants, p