Effect of different shrub species on their sub‐canopy soil and vegetation properties in semiarid regions

Abstract

Shrubs are one of the most dominant plant types in semiarid ecosystems all over the world. What remains to be investigated is how soil and vegetation characteristics vary under canopy of different species of shrubs in these regions. Thus, this study aimed to compare the effect of three shrub species (Amygdalus scoparia, Ebenus stellata, and Daphne mezereum) on soil and vegetation characteristics under their canopies in semiarid rangelands in Iran for restoration purposes of degraded areas. Fifteen sites were selected in such three shrub species, which were found close to each other in each site. Soil and vegetation characteristics were measured under the shrubs, comparing with outside the shrub canopies (control). One‐way ANOVA and nonmetric dimensional scaling were used to clarify the differences of the effects of different shrub species on sub‐canopy soil and plants. The results indicated that the effect of different species of shrubs on soil properties was not equal, more pronounced by A. scoparia. Similarly, the highest value of Shannon‐Wiener diversity was recorded under A. scoparia (2.07) as compared with D. mezerum (1.76), E. stellata (1.41) (F = 32.25, p < 0.01). The highest and lowest values of Menhinick richness index were observed under A. scoparia (3.43) and E. stellata (1.46), respectively (1.41) (F = 13.30, p < 0.01). Compared with two other shrubs, a taller canopy in A. scoparia (3.50 m vs. 2.60 m and 1.83 m) probably led to greater litter input by the shrub. Different effects of different species of shrubs on sub‐canopy soil and vegetation should be considered in the restoration projects of degraded semiarid rangelands.

Effects of shrub encroachment on grassland community and soil nutrients among three typical shrubby grasslands in the alpine subhumid region of the Qinghai-Tibet Plateau, China

“…Vegetation types differ in nutrient requirements and utilization ability (Yang et al, 2010). The height, canopy surface, and distance from the canopy to the ground of the three studied shrubs have different effects on the soil and plant communities (Erfanzadeh et al, 2021). Many studies have found that shrubs increase soil N, P, and K (Turpin-Jelfs et al, 2019), and SA and LT shrubs also significantly increase soil TN, TP, and TK in the upper soil layer.…”

“…Studies in the northern grasslands of China have shown that shrub encroachment reduces the herbaceous abundance and aboveground biomass and that shrub type and climate are dominant factors (Zhou et al, 2019). Erfanzadeh also found that shrub type was an essential factor affecting shrub understory herbaceous communities' productivity and species diversity in semiarid regions (Erfanzadeh et al, 2021). Shrub height and leaf characteristics significantly influence the vegetation characteristics and soil properties of the shrub understory .…”

“…Shrub expansion has been shown to destroy the original grassland vegetation, decrease species diversity, and reduce the primary productivity of grassland while increasing soil infiltration (Howard et al, 2012;Hu et al, 2022), changing soil nutrient patterns, and reducing soil nutrient pools (da Silva et al, 2016). However, it has also been shown that shrub invasion of grasslands increases grassland biomass, plant diversity, and richness (Erfanzadeh et al, 2021), promotes nitrogen mineralization (Maestre et al, 2009), and improves soil fertility (Ratajczak et al, 2012). Shrub species and the degree of shrub encroachment may explain these inconsistencies (Eldridge and Ding, 2020).…”

Herbaceous vegetation changes along a bush encroachment intensity gradient in a montane area

“…Bushes have been reported to often facilitate annual forbs (Rodríguez‐Echeverría & Pérez‐Fernández, 2003). According to Erfanzadeh et al (2021), bushes increase the diversity of forbs, possibly due to shading effects on reducing evapotranspiration and enhancing soil moisture for drought‐sensitive species in semiarid areas. Forbs do not usually contribute much to biomass production in grasslands, although they make a significant contribution to the overall plant species diversity (Van Oudtshoorn, 2015).…”

“…Herbaceous species, such as C. dieterlenii, C. lyrata, B. humilis , P. sphacelatum and P. luteo‐album , grew well in areas under bush canopy but with a low density of bushes. This suggests that these species are shade‐loving and their growth is enhanced when the canopy of the bushes is wide (Erfanzadeh et al, 2021), although they may be outcompeted when the bushes are at a high density.…”