مطالعه غنای گونه‌ای و تشابه پوشش سطحی و بانک بذر خاک در مناطق خشک آتریپلکسکاری شده شهریار

Plant cover may be the most important factor in conserving the soil from water and wind erosion. Wise management of plant cover needs accurate and sufficient information from vegetation and soil seed bank capacity. Evaluation of changes in vegetation and soil seed bank after a restoration operation can show the role of land management. The relation between these two, indicates the necessity of study the areas after restoration operation. To determine the species richness and similarity of plants and soil seed bank, sampling was done in ungrazed 18 year old Atriplex cultivated area and natural exclosure non-cultivated area. In the fall of 2010 randomized-systematic sampling of seed bank was conducted along four 200 m transects in each region. Five one-square-meter plots with 50 meter intervals along each transect (total of 20 plots in each region) were deployed. Soil samples from the depth of 0-5 and 5-10 cm were collected using auger and transferred to the greenhouse for planting in the proper beds. Plant cover was also estimated and recorded in the fall and spring of 2011 in each plot. Sorenson’s quantitative index was used to measure the similarity between soil seed bank and vegetation cover in each plot. To compare the characteristics of soil seed bank, containing seed bank similarity to vegetation, seed bank richness, palatability classes and life forms, between two regions, unpaired t-test, and between two depths of each region paired t-test were applied. One-way ANOVA and Duncan’s test were used separately to compare the palatability classes and life forms in each region. The results showed that, similarity of plant cover and soil seed bank, also soil seed bank richness in the depths of 0-5 and 5-10 cm had significant difference between planted and non-planted areas. The results also showed that similarity of soil seed bank and plant cover in the planted area is 60% for the first depth and 24% for the second depth. It’s 84% in the first and 40% in the second depth of non-planted area. All palatability classes showed significant difference between two regions. All kinds of life forms except Hemicryptophytes had significant difference between two areas.