Variation in the rates of biomass removal by soil macro-fauna in different land uses at Rashad, South Kordofan, Sudan

Travaux du Muséum National d’Histoire Naturelle “Grigore Antipa” 65 (2): 173–197 (2022) doi: 10.3897/travaux.65.e95270 RESEARCH ARTICLE Variation in the rates of biomass removal by soil macro-fauna in different land uses at Rashad, South Kordofan, Sudan Khalid A.E. Eisawi1, 2, Indra Prasad Subedi3, Emad H.E. Yasin4, 5, Christine Dakele Yode6, Hong He1 1 College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China 2 College of Forestry and Rangeland, University of East Kordofan, Rashad, Sudan 3 Central Department of Zoology, Tribhuvan University, Kathmandu, Nepal 4 Faculty of Forestry, University of Khartoum, Khartoum North, 13314, Sudan 5 Faculty of Forestry, University of Sopron, Bajcsy-Zsilinszky ut. 4, Sopron, 9400, Hungary 6 Felix Houphouët Boigny University (UFR Biosciences), Natural Environment and Biodiversity Conservation Laboratory, Abidjan, Côte d’Ivoire Corresponding author: Hong He () Received 23 September 2022 | Accepted 11 November 2022 | Published 31 December 2022 Citation: Eisawi KAE, Subedi IP, Yasin EHE, Yode CD, He H (2022) Variation in the rates of biomass removal by soil macro-fauna in different land uses at Rashad, South Kordofan, Sudan. Travaux du Muséum National d’Histoire Naturelle “Grigore Antipa” 65(2): 173–197. https://doi.org/10.3897/travaux.63.e95270 Abstract One of the main implications of reducing biodiversity is the loss or decline of ecosystem function. We have previously seen in the Rashad location that agricultural practices have a lower effect on ant biodiversity. However, how they affect the environmental services, they provide is unclear. The main objective of this study was to evaluate whether the conversion of native areas into agricultural systems affects the removal of biomass carried out by ants, an important ecosystem function linked to decomposition and predation. We sampled three transects from (the Rashad district). Each sampling plot consisted of a grid of 12 pitfall traps filled with sardine baits (simulating animal organisms) and bananas (as attractive vegetable resources). In addition, grass seeds (Sorghum bicolor) were applied in both natural (Campo, Kubos, and forest) and agricultural settings (soy monoculture, pastures, and organic agriculture). The Results showed that ant’s removal was highest in sardine with an average of 87.3g (σ ± 23.8), followed by banana (average of 70.5g, σ ± 31.5) and lowest in the seed (mean of 7.8g, σ ± 7.3) (highest p = 0.017). Only the soy monoculture regions showed the lowest levels of sardine removed, indicating an effect associated with the kind of land use. Because little biomass is eliminated in both natural and agricultural settings, no effect of the seeds bait has been observed. As for the banana bait, the Copyright Eisawi, Subedi, Yasin, Yode & He. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 174 Eisawi, Subedi, Yasin, Yode & He data suggested a redundancy effect with another group of macro-fauna). Our results suggest that there is a redundancy effect with another group of macrofauna. However, macrofauna biomass (excluding ants) does not explain this biomass removal. In addition, it detected no impact of ant species composition on removed biomass. The reduction of sardine and banana biomass was correlated with ant richness, indicating that the effects on ecosystem function depend on the particularities of each evaluated role (such as resource type), the type of land use, and the ant richness in the study area. Keywords Biodiversity; Biomass; soil macro-fauna; land uses types; Rashad; Sudan. Introduction Expansion of agricultural systems affects local and global biodiversity (Lanz et al. 2018), with the extent of these impacts varying based on local characteristics, taxon, and type of agricultural system implanted (Kassa et al. 2017; Ortiz et al. 2021). However, the influence on biodiversity is just as crucial as determining what influence the growth of agricultural systems has on ecosystem function. Biodiversity-ecosystem function hypothesis, a theory debated in the early 1990s, states that a reduction in biodiversity (number of species, genetic variability, etc.) results in the decline of ecosystem processes (DeLaplante and Picasso 2011). However, this is not a universal effect (Scherer-Lorenzen et al. 2005); Reviews and meta-analyses on this subject have all come to the same conclusion that the reduction in ecological functionality is depends on the local characteristics, the assessed ecosystem’s function, and the type of disturbance (Spurgeonet al. 2013; Duru et al. 2015; Boltovskoy et al. 2021). This large number of divergent results, found in studies on ecosystem services due to the effect of anthropization, makes the predictability of these impacts complex and is depends on studies that focus on different environments, processes, and types of disturbance (Pinter-Wollman et al. 2013). However, most previous studies have focused on plant or aquatic communities’ ecology (Finke and Snyder 2010; Gaertner et al. 2014; Arias-Real et al. 2021) with focusing limitedly on the ecological processes that rely on terrestrial fauna. Among these ecological processes, we highlight the predation and decomposition exerted by terrestrial fauna, which is of fundamental importance to the ecosystem’s functioning and regulation (Nichols et al. 2008). Predation allows for the control of the wide range of populations in a particular ecosystem. Few studies have examined how agricultural expansion affects biodiversity and how this manifest in the ecological processes of the Rashad, which has one of the highest, levels of endemism and degradation in the world (Underwood et al. 2009; Wilson et al. 2017). The expansion of the agricultural frontier in the Rashad is a reality with densely occupied areas mainly in the south of this biome (UNDP 2003). The effects of this occupation have been assessed using a variety of taxa, with ants being one of the most studied (reviewed by Blüthgen et al. 2003; Camarota et al. 2020), as it is one of the most abundant taxa Different land uses at Rashad, South Kordofan, Sudan 175 with the highest biomass in tropical habitats (Adams et al. 2013) and interesting behaviors. In Rashad, it is estimated that ants can consume about 13 to 17% of the leaf biomass of woody plants annually (Eisawi et al. 2021). Ants can also act as predators, controlling the population of agricultural pests (Harvey and Eubanks 2004; Frizzi et al. 2020) or as seed dispersers (Aranda-Rickert and Fracchia 2012) particularly these contain some attractive seed appendage (Munguía-Rosas et al. 2009). Another important ecological service is the removal of organic biomass from the surface to the subsoil, which improves the nutritional qualities of the soil (Chen et al. 2013). A (...truncated)