Soil seed bank in different habitats of the Eastern Desert of Egypt

Abstract

The floristic composition and species diversity of the germinable soil seed bank were studied in three different habitats (desert salinized land, desert wadi, and reclaimed land) in the Eastern Desert of Egypt. Moreover, the degree of similarity between the seed bank and the above-ground vegetation was determined. The seed bank was studied in 40 stands representing the three habitats. Ten soil samples (each 25 × 20 cm and 5 cm depth) were randomly taken per stand. The seed bank was investigated by the seedling emergence method. Some 61 species belonging to 21 families and 54 genera were identified in the germinable seed bank. The recorded species include 43 annuals and 18 perennials. Ordination of stands by Detrended Correspondence Analysis (DCA) indicates that the stands of the three habitats are markedly distinguishable and show a clear pattern of segregation on the ordination planes. This indicates variations in the species composition among habitats. The results also demonstrate significant associations between the floristic composition of the seed bank and edaphic factors such as CaCO3, electrical conductivity, organic carbon and soil texture. The reclaimed land has the highest values of species richness, Shannon-index of diversity and the density of the germinable seed bank followed by the habitats of desert wadi and desert salinized land. Motyka's similarity index between the seed bank and the above-ground vegetation is significantly higher in reclaimed land (75.1%) compared to desert wadi (38.4%) and desert salinized land (36.5%).

Soil Seed Bank and Plant Community Development in Passive Restoration of Degraded Sandy Grasslands

“…The IS values in all of our sites are higher than those in previous grassland studies [28,29], possibly because of differences in the ratio of perennials to annual species (IS typically decreases with an increasing ratio of perennial to annual species) [1,42]. Lower IS values in S4 and S7 comparing with S0, partially because the dormancy seed would not regenerate easily without dormancy breaking, indicating that during initial recovery, new species which are not present in the soil seed bank can be added through dispersal from the surrounding area.…”

“…[16,17,41]. Fernández-Lugo (2009) and Gomaa (2012) argued that grazing cessation and microhabitat improvements (mainly increased soil nutrient and water availability) altered the proportions of the dominant species and thus increased plant density, coverage, and height [41,42]. At our sites, the target species (C. microphylla and C. Squarrosa) are still present, essentially priming the sites for restoration.…”

Correlation of soil properties with weed ocurrence in sugarcane areas

“…This result contrasts some studies performed in different management systems and climatic conditions (Shaukat & Siddiqui, 2004;Gomaa, 2012), which has found more species in the phyto-sociological survey than in SSB. However, the result of this study emphasizes the importance of knowledge of SSB in cultivation areas because it represents its management history and it can be used as a database for future infestation potential of the area, which can be expressed according to favorable environmental conditions (Lopes et al, 2004).…”

“…Although climatic factors usually influence the distribution of species on a large scale, soil factors are considered the most influential (Otto et al, 2007), as it can change the growth of certain species and explain their presence and relative abundance in certain locations of the cultivated areas (Walter et al, 2002;& Shaukat Siddiqui, 2004;Udoh et al, 2007;Iwara et al, 2011;Gomaa, 2012). Taking it into consideration, it is necessary to know which factors may be related, directly or indirectly, and determining the occurrence of some weed species, since, with such information, it would be possible to schedule a more appropriate management.…”

Responses of Soil Seed Bank and Vegetation to the Increasing Intensity of Human Disturbance in a Semi-Arid Region of Northern China

“…For example, it was reported that the soil seed bank was sufficient to restore degraded vegetation in the Hunshandak Sandlands in northern China due to enough seeds in the soil [17], while in northeastern Hungary it was not viable to restore degraded vegetation with only the natural soil seed bank due to the lack of native species [18]. It has been proven that many factors could affect the seed density and species composition, such as seed size and shape [19], historical vegetation [20], microhabitat variation [21], human disturbance [22], season variation [23], and climate changes [24]. Many studies have been conducted in recent years that attempt to understand the effects of human disturbance on the soil seed bank [25,26].…”