Temporal and spatial dynamics of vesicular-arbuscular mycorrhizal fungi under the canopy of Zygophyllum dumosum Boiss. in the Negev Desert

The temporal and spatial dynamics of vesicular-arbuscular mycorrhizal (VAM) fungi were investigated in a desert ecosystem. Soil samples under the canopy of Zygophyllum dumosum were collected monthly between November 1999 and October 2000 from 0-10 and 10-20 cm depths. VAM fungal colonization and spore density were used to compare the responses of VAM fungi to soil conditions. The mean percent colonization and spore density of VAM fungi reached maximal values in November 1999 and September 2000. Soil moisture was positively correlated with colonization of VAM structure groups. Vesicular and arbuscular colonization were positively correlated with soil organic. matter and total soluble N. Spore density was also positively correlated with total soluble N. Our results suggest that spore density and the extent of vesicular and arbuscular colonization are useful indicators for evaluating changes in desert soil ecosystems. (C) 2002 Published by Elsevier Science Ltd.