Abstract Land degradation deteriorates biological
productivity and affects environmental, social, and
economic sustainability, particularly so in the semiarid
region of Northeast Brazil. Although some studies
exist reporting gross measures of soil microbial
parameters and processes, limited information is
available on how land degradation and restoration
strategies influence the diversity and composition of
soil microbial communities. In this study we compare
the structure and diversity of bacterial communities in
degraded and restored lands in Northeast Brazil and
determine the soil biological and chemical properties
influencing bacterial communities. We found that land
degradation decreased the diversity of soil bacteria as
indicated by both reduced operational taxonomic unit
(OTU) richness and Shannon index. Soils under native
vegetation and restoration had significantly higher
bacterial richness and diversity than degraded soils.
Redundancy analysis revealed that low soil bacterial
diversity correlated with a high respiratory quotient,
indicating stressed microbial communities. By contrast,
soil bacterial communities in restored land
positively correlated with high soil P levels. Importantly,
however, we found significant differences in
the soil bacterial community composition under native
vegetation and in restored land, which may indicate
differences in their functioning despite equal levels of
bacterial diversity.
Keywords T-RFLP Microbial ecology Land
degradation Molecular profiling
Introduction