Published online by Cambridge University Press: 15 October 2009
There is very little information on effects of particulate pollution from cement factories in the Middle East and northeastern Africa. Variations of natural vegetation, germinable soil seed bank and species diversity were therefore investigated amongst four study sites situated at different distances from the Suez Cement Company factory, south of Suez, Egypt. The composition of plant life-forms was similar in both vegetation and seed-bank communities, with only site-dependent differences in their proportional values. For the standing vegetation, chamaephytes attained the highest relative density and cover, while hemicryptophytes and geophytes exhibited the lowest values. Germinable soil seed bank of all life-forms tended to increase with distance from the cement-dust pollution source. Vegetation, seed rain and seed banks of hemicryptophytes and geophytes were the most affected by cement-kiln dust accumulation in the area. The ratios of seed-bank/seed-rain in all life-forms were less than unity, with a narrow range of variation amongst sites and species. The germinable seed bank was more affected by cement-kiln dust accumulation than the seed rain in all species and life-forms. The species diversity of perennial plants was greater than that of annuals, with values increasing as distance increased from the cement-dust pollution source. Diversity in the standing vegetation Was higher than that of the germinable seed bank. Differences in the standing vegetation and seed-bank reserves were observed in the different study sites. According to their response to cement-dust accumulation, the plant species (listed in text) in the study area were separated into four major groups: (1) tolerant species; (2) non-tolerant species; (3) species having intermediate tolerance; and (4) indifferent species. Management considerations for the conservation of vegetation in cement quarrying sites and around cement factories were put forward to optimize recovery and restoration of vegetation in sites polluted by cement dust.