The terrestrial biodiversity continues to decline globally due to the increasing of human impacts (Díaz et al., 2019)The land use intensification is a global issue that affects the delivery of multiple ecosystem services via biodiversity loss (Allan et al., 2015). This is because, the conversion of land use to monoculture plantations leads to the degradation of ecosystem functions and the loss of biodiversity (Fitzherbert et al., 2008). Moreover, numerous studies have shown that the conversion of natural lands to agriculture, together with agricultural intensification that makes the greatest contributions to soil biodiversity loss (Orgiazzi et al., 2016, Sofo et al., 2014). On the other hand, the variation of land use and land coverage has been proven to be an important factor for biodiversity distribution (Zhang et al., 2016, Tao et al., 2016). The SMF is one of the soil organisms that are thought to be influenced by unsustainable human disturbances.
The SMF are animals that inhabit different soil layers, including litter and the soil surface, and are visible to the naked eye (Seeber et al., 2022). The SMF consists of a large number of different organisms that have an average body width greater than 2 mm (Zulu et al., 2022). Taxonomically, they are heterogeneous and mostly belong to the phyla Mollusca, Annelida, and Arthropoda (Seeber et al., 2022), which represent 23% of the richness of living organisms (Rojas-Múnera et al., 2021). The functional role of SMF is strongly supported by its diversity, abundance, and community composition (Wibowo et al., 2021). The effects of SMF on the soil ecosystem are indispensable. Of which, the interacting effect of SMF with microorganisms, contributes to nutrient cycling (Wagg et al., 2014), erosion control through stabilizing soil aggregates (Brussaard et al., 2007), and soil carbon storage (Lubbers et al., 2013). Moreover, the SMF have the greatest potential to modify the soil environment through their activities (Jouquet et al., 2006).
Despite the fact that SMF play an important role in soil fertility maintenance, they are negatively affected by agricultural intensification (Melman et al., 2019), and nature of the land management can exert a strong influence on SMF community (Moreira et al., 2008, Barrios et al., 2005, Barros et al., 2002). Consequently, the SMF distribution, abundance, and diversities vary depending on residue inputs and soil management practices (Mutema et al., 2013, Manhães et al., 2013). The ecosystems that have a well-developed tree component and surface litter cover will host more diverse and abundant communities of SMF (Lavelle et al., 2022). On the other hand, different studies have shown that anthropogenic activities, such as agricultural intensification and land use change, reduce faunal abundance and the overall diversity of soil organisms (De Vries et al., 2013). The variation in depth could affect the distribution of SMF, and the changes in the soil ecology could also alter habitat conditions and resource availability for different groups of SMF (Rousseaua et al., 2013).
Agroforestry (AF) is a sustainable land use practices that has come to the attention of global analysts and policy makers concerned with environmental sustainability (Nair and Garrity, 2012). This is because AF has the potential to conserve biodiversity and ecosystem services without compromising the productivity of land (Torralba et al., 2016). Several studies highlighted the positive impacts of AF on the biodiversity of SMF, for instance, (Barros et al., 2002) stated that AFPs are known to be associated with the presence of continuous soil cover, which appears to be related with abundant and diverse SMF communities. Another study in the western Colombian Amazon also found that the cacao based AFP in degraded pastures demonstrated the capacity of the system to increase macrofauna biodiversity in the soil (Suárez et al., 2021). Moreover, the higher abundance and diversity of SMF under AFP was reported compared to any other type of land use type (Barros et al., 2002), and (Pauli et al., 2011) also found higher SMF abundance and diversity under AFP.
In Ethiopia, different types of AFP have been practiced in the southern region. However studieson AFP types mainly focused on diversity of woody species in traditional AFP (Molla et al., 2023, Abebe, 2005), determinants of crop diversity and composition in enset-coffee homegarden AF (Abebe, 2013). Other researches such as the composition and diversity of avifauna across different types of AFS (Yasin and Tekalign, 2022), the contribution of AFP to --- (Tega and Bojago, 2023, Adane et al., 2019, Sahilu, 2017), the coffee based AF (Jemal et al., 2021), and the indigenous AFS on biodiversity, carbon stocks, and litterfall (Tesemma, 2013), have been conducted. However, the variation of SMF species richness, abundance, and diversity across different AFP types from the land management practices aspect wasn’t conducted. Therefore, the overall aim of the present study was to investigate the SMF abundance and diversity across different AFPs caused by land conversion. To fulfill this aim, the SMF was collected from three depths of the respective soil monolith from AFP to test (i) whether SMF community structure differs between AFP types, (ii) SMF community structure within soil monolith depths, (iii), analyze the relationship between soil properties, SMF abundance, diversity, richness, and evenness and (v) analyze the interaction effect of soil depth and AFP on SMF composition in the drylands of southern Ethiopia. The SMF community structures differ between the different AFP types due to differing plant diversity and land management practices.