Geoderma 363 (2020) 114144 Contents lists available at ScienceDirect Geoderma journal homepage: www.elsevier.com/locate/geoderma A preliminary investigation of the effect of mole cricket (Gryllotalpa unispina T Saussure; Orthoptera: Gryllotalpidae) activity on soil evaporation in semiarid Loess Plateau of northwest China ⁎ Xi Yanga,b, Ming'an Shaoa,b,c,d, Tongchuan Lia,c, , Yuhua Jiae, Xiaoxu Jiac, Laiming Huangc a State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, China b College of Natural Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712100, China c Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China d College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China e College of Water Conservancy, Shenyang Agricultural University, Shenyang 110866, China ARTICLE INFO ABSTRACT Handling Editor: Yvan Capowiez Many insect species, especially soil-inhabiting ones, greatly affect the physical and chemical properties of soil. The Keywords: widespread soil-inhabiting mole cricket on the northern Loess Plateau creates subterranean tunnels, damages Soil-inhabiting insects topsoil structures, and likely alters soil infiltration, erosion, and evaporation. In this study, we assessed the effectof Disturbance adult and immature mole crickets (Gryllotalpa unispina Saussure; Orthoptera: Gryllotalpidae) on soil water eva- Subterranean tunnels poration in loam soil. A series of simulation experiments was conducted in iron buckets (20 cm in diameter and Soil water 20 cm high) filled with disturbed soil at the Shenmu Erosion and Environment Research Station. Thesoilwas saturated and drained until the water content approached the field moisture capacity (25.3%), and then the soil was subjected to evaporation for 58 days. Evaporation was found to occur in two stages. In the first 18 days, daily evaporation in soil with adult and immature mole crickets was significantly (P < 0.05) lower than that in soil without mole cricket. Compared with bare soil treatment, the cumulative evaporation of soil treated with adult and immature mole crickets decreased by 24.6% and 13.9%, respectively. In the second stage, daily evaporation in soil treated with mole cricket was greater than that in bare soil due to the higher soil moisture in treatments with mole cricket in the first stage. Under the condition of continuous drought, mole cricket activity had a lag effectonsoil water evaporation. The effects of mole cricket activity on soil evaporation depended on the soil-surface disturbance area, i.e., a larger disturbance area corresponded to more greatly reduced soil-evaporation function. These results can help elucidate the effects of soil-inhabiting insects on water movement in semiarid areas. 1. Introduction forming macropores with a diameter of 1–14 mm (Bastardie et al., 2003) and accumulating water-stable aggregates on the soil surface, thereby In 1999, the policy of returning farmland to forests and grassland changing soil bulk density (Tucker et al., 2004) and reducing surface was implemented. Since then, the vegetation coverage of the Loess runoff and soil erosion by increasing water infiltration and roughness Plateau in northwest China has increased from 6.5% in the 1970s to (Blanchart et al, 2004; Evans et al., 2011; Jouquet et al., 2012). As around 50% in 2010 (Wang et al., 2012) and reached 60.2% by the end ecosystem engineers, social ants can form continuous macroporous tun- of 2013 (Gao et al., 2017). However, with the improvement of the nels and charms during nesting (Karlen et al., 2003). Ant activities can ecological environment, the massive restoration of vegetation provides form macropores in the soil and agglomerates on the soil surface, thereby a large amount of food and suitable living space for soil animals (Wang increasing rainfall infiltration and reducing soil water evaporation (Li et al., 2010). The diversity and quantity of soil animals in the Loess et al., 2017a), drainage, and runoff (Brevik et al., 2015) around the nest. Plateau are also increasing. Mole crickets have larger body width than ants and earthworms and Soil organisms can seasonally and temporally influence many factors have strong forelegs suitable for digging. A mole cricket spends almost all of soil formation and structure (Brevik et al., 2015). The earthworm its life underground and forms underground tunnels for feeding, pro- consumes soil organic matter when excavating a tunnel (Edwards, 2004), tecting, and mating (Bailey et al., 2015). X-ray CT scans (Bailey et al., ⁎ Corresponding author at: 26 Xinong Road, Yangling, Shaanxi 712100 China. E-mail address: [email protected] (T. Li). https://doi.org/10.1016/j.geoderma.2019.114144 Received 23 June 2019; Received in revised form 22 November 2019; Accepted 15 December 2019 Available online 28 December 2019 0016-7061/ © 2019 Elsevier B.V. All rights reserved. X. Yang, et al. Geoderma 363 (2020) 114144 2015; Villani et al., 2002), fiberglass resin (Brandenburg et al., 2002), In the arid and semi-arid regions of the Loess Plateau, with the and thin slurry of orthodontic plaster (Li et al., 2018) were used to large-scale restoration of vegetation and the massive increase of soil generate the three-dimensional images of mole cricket tunnels. The animals (ants, mole cricket, mice, etc.), the destruction of soil structures tunnels extended in horizontal and vertical directions, and the mean because of soil animals and the changes in soil water movement cannot diameter and depth of adult mole crickets tunnels were significantly be ignored. In recent years, the community of mole cricket in the larger than immature mole cricket tunnels (Li et al., 2018). In the hor- Liudaogou Catchment has gradually increased, especially in the semi- izontal direction, branching structures develop in all directions, and egg naked land, but its effect on the ecological environment has rarely been chambers are built next to horizontal tunnels (Endo, 2007). Mole crickets studied. The structure of the mole cricket tunnel and its influence on are solitary insects. A vertical tunnel usually holds only one mole cricket soil erosion and hydrologic processes were studied in the Liudaogou (Endo, 2007). Regardless of the tawny mole cricket, Scapteriscus vicinus Catchment (Li et al., 2018), but minimal attention was paid to the ef- Scudder, and the southern mole cricket, Scapteriscus borellii Giglio–Tos, fects of mole crickets activities on soil evaporation. their horizontal and vertical tunnels interconnect to form Y-shaped We hypothesized that the disturbance of the soil surface during channels (Villani et al., 2002). The depth of tunnel excavated by a mole long-term drought can reduce soil evaporation and increase water cricket can reach 70 cm (Brandenburg et al., 2002), and the width of the storage in small-scale soils. Therefore, the objectives of this study are to tunnel is 2–3 times of the mole cricket’s body width (Bailey et al., 2015). (1) determine the influence of adult and immature mole cricket on soil Mole crickets (Gryllotalpa unispina Saussure; Orthoptera: Gryllotalpidae) evaporation and (2) investigate the relationship between disturbance feed on the young roots, tender stems, and newly sprouted seeds of area created by burrowing mole crickets on the surface and evapora- various plants, so they dig for food under 2 cm of the surface. Therefore, tion. On the basis of previous studies on soil evaporation, this study has the ground often shows swollen fresh soil, which is the horizontal tunnel carried out a preliminary exploration of the mole cricket surface dis- under the bulge. Endo (2007) reported that the horizontal tunnel ex- turbance as a key factor affecting evaporation. This study combines soil cavated by mole cricket is 5 cm below the surface. The tunnel structures animals and soils to enrich the research content of soil animals and soil, vary with mole cricket type and affected by factors, such as soil moisture and provides new ideas and perspectives for studying the changes of (Hertl and Brandenburg, 2002), bulk density (Brandenburg et al., 2002; soil physical and chemical properties. Villani et al., 2002), environmental conditions, density of other in- dividuals, food resource distribution, and surface cover (Comber et al., 2. Materials and methods 2006). However, numerous horizontal and vertical channels formed during the excavation process affect soil hydraulic properties. Channels 2.1. Experimental site formed by mole crickets in soil are conducive to water flow and reduce surface runoff (Bailey et al., 2015). Horizontal caves on the surface of the The study site is located at the Shenmu Erosion and Environmental soil can intercept rainfall and reduce runoff, thereby increasing water Research Station in the Liudaogou Catchment of Shenmu County, penetration (Li et al., 2018). Agglomerates produced by earthworms Shaanxi Province, China (E110°21′–110°23′ N38°46′–38°51′). Situated have a certain water stability (Jouquet et al., 2012), whereas soil parti- in the hinterland of the Loess Plateau, it is a typical water–wind erosion cles formed by mole crickets’ horizontal excavation on the soil surface crisscross region. The area of the catchment is 6.89 km2, and the alti- are extremely vulnerable to erosion by rainstorm and to surface runoff tude is 1081–1274 m. The annual precipitation is 437 mm, and over (Li et al., 2018). When mole crickets excavate a horizontal channel, the 81% of the precipitation is concentrated in June–October, which be- surface and lower soil layer become separated and form a new soil layer, longs to a semiarid continental climate zone. The aridity index is 1.8, which has high porosity as sand or stone covering layer. The area of this and the mean annual potential evapotranspiration reaches 785 mm. new layer on the soil surface expands with the activities of mole crickets. The main vegetation type in the catchment is drought shrub-clustered This new soil layer may affect soil evaporation in a manner similar to grassland (Caragana korshinskii and Stipa capillata Linn).