Introduction
Wind erosion, the movement of course and fine particles by wind, is among natural process that mostly occurs under dry conditions and high wind velocity (Mirhasani et al., 2019; Jarrah et al., 2020), and degrade more than one-third of the ’Earth’s land surface (Fattahi et al., 2020). The wind erosion may be accelerated by anthropogenic pressures such as overgrazing rangelands, excessive clearances of native vegetation, deforestation, abandoning farmland, monoculture systems, over-harvesting vegetation, or leaving cultivated lands fallow for a long time (He et al., 2006; Chen et al., 2013), resulting in an increase in the rates of soil loss. Wind erosion decreases water quality and negatively impacts biodiversity and climate changes (Lal, 1994; Fattahi et al., 2020). In addition, the negative effects of wind erosion on soil nutrients have been reported; wind erosion may negatively affect nutrients such as nitrogen by blowing off the most fertile topsoil (Lei et al., 2019). Wind erosion may also damage young plant tissues (Zheng et al., 2020) and accelerate shrub expansion, resulting in alteration of plant community composition (Alvarez et al., 2012). Therefore, wind erosion is categorized as one of the most critical global environmental issues in recent decades.
Mulching is a common method among several methods and materials that have been evaluated to find suitable stabilizers for controlling wind erosion (Tibke, 1988; Manorama et al., 2021). Mulches are natural or artificial materials and are used to protect the soil from the damage of various factors such as wind and rain (Refahi, 2009). Oil (petroleum) mulch (hereafter oil-mulch) is one of the high-cost chemical mulches which can be sprayed over sand dunes to assist with re-vegetation (Amiraslani and Dragovich, 2011) and referes to oil products which are made of hydrocarbon mixtures and are used to cement sand particles (more details in Shojaei et al., 2020). Application or spraying of oil-mulches on the degraded and exposed soil to erosion reduces water evaporation (Chen et al., 2007), resulting in soil moisture manitenance and preventing sudden temperature changes (Ramakrishna et al., 2006). Also, oil-mulches facilitate plant establishment and growth conditions and, therefore, increase fertilization and soil productivity (Shojaei et al., 2020). For example, Jafarian (2006) reported that in the oil-mulched area in the central part of Iran in Kermen province, the germination ofHaloxylon persicum was nearly three times greater than that found in untreated surfaces. Also, further effects of oil-mulch treatments in stabilizing sand and encouraging seed germination have been reported (Farahpour et al., 2005). In this regard, the positive effects of oil-mulches application have been reported in terms of soil organic matter, soil water holding capacity, and soil organisms’ amount and activity (Pouyafar and Asgari Moghadam, 2006). However, the relative contributions of the oil-mulch treatment to vegetation diversity and condition have not received a great deal of attention, especially in arid regions.
Although the oil-mulche effects reduce by time, their application’s main goals are to increase soil stability and provide an opportunity for the establishment of other biological activities such as planting and seeding (Refahi, 2009). Generally, the Iranian Ministry of oil provides the oil-mulches at no cost for the purpose of sand stabilization. The first attempt to stabilizing shifting sand dunes and combating desertification was conducted using oil-mulch on 40 ha of dunes at Hamidieh, Albaravayeh, and Albaji in Khuzestan Province in September 1959 (Amiraslani and Dragovich, 2011). Following this project’s successful results, nearly 190,000 hectares of sand dunes were stabilized using oil-mulch over the 30 years, and this combat with desertification continues.
Satellite imagery and remote sensing (RS) techniques are among the popular methods to investigate vegetation cover and dynamic across extent areas such as mulched areas (i.e., Hashemimanesh and Matinfar, 2012). however, few studies have been done using RS to evaluate the effectiveness of oil-mulches treatment, especially in Iran’s arid regions. Ilam province in western Iran approximately contains 2000 ha dunes area; known as the Abougovair region; 40% of this region speared using oil-mulch in 2018. While, to continue this process, there is no information about the results of oil-mulch treatment on vegetation diversity and condition yet. Therefore, the current study tried to answer these following equations:
(1): Does short-term (one-year) oil-mulch treatment increase plant diversity (richness, evenness, and diversity) and vegetation components (percent of vegetation cover, litter, and bare soil)?
(2): Does short-term (one-year) oil-mulch treatment significantly increase vegetation conditions and RCS?
(3): Do RS tools (i.e., vegetation indices) have the potential for revealing vegetation change pre- and post-oil-mulch treatments?