Microbial Ecology

, Volume 63, Issue 3, pp 694–700

The Effect of Resource Islands on Abundance and Diversity of Bacteria in Arid Soils

Soil Microbiology


Bacteria and nutrients were determined in upper soil samples collected underneath and between canopies of the dominant perennial in each of three sites along a steep precipitation gradient ranging from the Negev desert in the south of Israel to a Mediterranean forest in the north. Bacterial abundance, monitored by phospholipid fatty acid analysis, was significantly higher under the shrub canopy (compared to barren soils) in the arid and semi-arid sites but not in the Mediterranean soils. Bacterial community composition, determined using terminal restriction fragment length polymorphism and clone libraries, differed according to the sample’s origin. Closer examination revealed that in the arid and semi-arid sites, α-Proteobacteria are more abundant under the shrub canopy, while barren soils are characterized by a higher abundance of Actinobacteria. The bacterial communities in the Mediterranean soils were similar in both patch types. These results correspond to the hypothesis of “resource islands”, suggesting that shrub canopies provide a resource haven in low-resource landscapes. Yet, a survey of the physicochemical parameters of inter- and under-shrub soils could not attribute the changes in bacterial diversity to soil moisture, organic matter, or essential macronutrients. We suggest that in the nutrient-poor soils of the arid and semi-arid sites, bacteria occupying the soil under the shrub canopy may have longer growth periods under favorable conditions, resulting in their increased biomass and altered community composition.

Supplementary material

248_2011_9957_MOESM1_ESM.doc (31 kb)
Supplementary Table 1Main characteristics of the three LTER sites sampled in this study (DOC 31 kb)
248_2011_9957_MOESM2_ESM.doc (84 kb)
Supplementary Figure 1Rarefaction curves calculated for observed OTUs with ≥85% sequence similarity. The clone libraries were amplified from inter-shrub (IS) patches and under shrub canopy (US), in arid, semi-arid and Mediterranean sites (DOC 83.5 kb)

Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  1. 1.Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert ResearchBen-Gurion University of the NegevBeershebaIsrael

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