The effect of Sarcopoterium spinosum on soil and vegetation characteristics

This study addressed the effect of the dwarf shrub Sarcopoterium spinosum on soil properties, soil moisture and vegetation characteristics (plant density and richness) in a semi-arid ecosystem. Vegetation characteristics and soil sample data were obtained from three areas: 1) beneath the S. spinosum patch, 2) between the patches and 3) from the open area. The results showed that the area beneath S. spinosum had significantly higher soil moisture content, organic matter, available ammonium, nitrate, and phosphorus compared to the areas between shrubs and open areas. The results also showed that the total plant density and richness decreased significantly beneath the shrub canopy compared to the areas between shrubs and open areas. Certain plant species are found only beneath the shrub canopy. Our results indicated that S. spinosum creates habitat heterogeneity by modifying the area beneath its canopy and influencing the community structure. Interactions and the mechanisms of interactions between S. spinosum and other annual plants play an important role in determining community structure and affecting the distribution of plant species beneath and around the shrub canopy. Thus, understanding such interactions and understanding their mechanisms are important issues that should be considered for rangeland management and conservation. (C) 2012 Elsevier B.V. All rights reserved.