Insight into the soil seedbank characteristics of the arid rangelands in Libya: A case study in Marmarica Plateau, Cyrenaica (Northeastern part of Libya)

الملخص

The current study was conducted in Daphna area, an arid region in Cyrenaica located at the northeastern part of Libyan Sea Coast at the Libyan-Egyptian Border. The soil was sampled in 40 different sampling sites along five different sectors through scraping the soil from 0-10 cm layer (25´25 cm) in the Platea and from 0-10 cm and 10-30 cm layers in the depressions and valleys. Using the floatation in a salt solution method, the seeds were extracted from the soil, counted and identified. The majority of the extracted seed were tinny (< 5 mm) and mainly belonged to annual species. Seeds density in the plateau ranged between 0 and 25400 seed m-2 with an overall mean of 4110 seed m-2 (±949.30 SE), which is adequate density when compared to similar arid ecosystems. The low-lying lands in depressions (Sakifas) and valleys (Wadis) retained higher seed density than the higher-lying lands on the plateau, and the northern areas retained higher density than the southern areas. The higher top soil layer (0-10 cm) in both Sakifas and behind the Dykes in valleys retained higher mean density than the layer (10-30 cm). The homogeneity of seed characteristics across the plateau and the dominance of annual and short-lived species could be a sign of degradation, and the absence of many perennial species in the soil seedbank may hamper any conservation or rehabilitation effort to improve these rangelands.