Draa oases are declared as a part of the biosphere reserve of Moroccan oases. These oases are agro-ecosystem dominated by the palm and fed by Draa Wadi, the longest in Morocco. Outside the oasis, the acacia trees and many pre-Saharan herbaceous species expand along the flooded areas and at the edges of temporary waterways. This desert vegetation creates a microclimate that favors the proliferation of a vast invertebrate diversity including Coleopteran species (beetles) that support the soil and flora-fauna ecosystem services. These insects play a very important role in the health of this environment. Indeed, they can perform the functions of ecosystems such as pollination, purification, biological control, and soil fertilization. In this chapter, the authors provide new information and update the list of the Coleopteran species in the Draa Valley. Thirty-one species and 15 families were observed through several entomological trips.
TopIntroduction
In terms of number and diversity, Coleoptera is the most important group of insects representing about a fourth of all living organisms with significant ecological interactions (Peris, 2020). This order is very abundant in the forest ecosystem representing about 40% of insects and 400,000 species exist worldwide (Hong et al., 2017). Several coleopteran species provide valuable ecosystem services including forage fouling, nitrogen volatilization (break down dung to usable form of nitrogen), pest control (decompose dung may reduce parasites) (Losey & Vaughan, 2006), and soil fertilization, which support many ecological functions. For example, subfamily Scarabaeinae (Coleoptera: Scarabaeidae), through manipulating feces assures the bioturbation, parasite suppression, the seed dispersal, nutrient cycling, and plant growth enhancement (Nichols et al., 2008). For example, Carabids are frequently used as indicators (Parisi et al., 2005; Rainio et al., 2003) to monitor the influence of different types of control (Porhajašová & Babošová, 2022; Legrand et al., 2011). In fact, they are used as indicators in habitat alteration (Rainio et al., 2003). In managed area, carabids are less rich and of smaller body size (Blake et al., 1996) and decrease in isolated and fragmented zones (de Vries, 1994). They are affected by the elements like soil, water, and elevation (Eyre & Luff, 1990), are sensitive (decreased) to forest cutting (Niemela et al., 1993), and to growing urbanization (Do & Choi, 2022). The importance of the coleopteran species resides in one of the phases of development whether it is the adult or larval form or in both forms. For example, several groups of coleopteran like scarabeids and carabides live the larval stage in the litter while in the adult stage use soil as a food source (Jeffery et al., 2010). Globally, the coleopteran species are found in several ecosystems and climatic zones including the arid areas such as the Middle Draa Valley (MDV) (Southeastern of Morocco). In this area, the knowledge on coleopteran species is not updated. These valleys belong to the biosphere reserve of Moroccan oases declared by UNESCO in 2000. The main ecosystems are oases dominated by the palm and fed by Draa Wadi and surrounded by steppe environments. These ecosystems create microclimate that favors the proliferation of various families of beetles. In this chapter, several field trips were carried out between 2010 and 2020 to identify the coleopteran species in this region.