| Karat is one of the world’s typical ecologically fragile zones,and southern China’s karst is a distinct area of a concentrated and continuous distribution of karst in the world.The high population density of the region’s rural areas,the huge population pressure and high-intensity agricultural activities have led to serious environmental problems of rocky karst desertification,which seriously restrict the region’s sustainable development.Under the funding of the National 12 th Five-Year Plan Key Science and Technology Support Programme and the13 th Five-Year Plan National Key Research and Development Programme,the research unit of the project selected the potential-light rocky desertification type area of the Salaxi Karst Plateau Mountains in Bijie,Guizhou,for a comprehensive management demonstration,in which planting with walnut,Rosa roxbunghii,Trifolium repens and their combinations is an important model for vegetation restoration,and part of the untreated area is used as a natural restoration area.To evaluate the ecological restoration effect of rock desertification management in karst areas,soil mites were collected in July,October and December 2021,using the soil mite community diversity index,richness index,evenness index,similarity index,ecological group of predatory gamasid mites（Mesostigmata: Gamasina）and an ecological group of oribatid mites（Acari: Oribatid）to compare and analyze the differences in soil mite community structure in different levels of rock desertification environments under natural and anthropogenic restoration method.The relationship between soil mite community structure and soil physicochemical factors in different environments was analyzed by redundancy analysis,two-factor interaction analysis and correlation analysis.The following main findings were obtained.（1）A total of 5889 soil mites were captured in the study area,belonging to 107 genera in 60 families of 3 orders,with an average density of 2604.83 heads/m2.The number of families,genera,individuals and average density of soil mites captured in the natural restoration method was greater than in the anthropogenic restoration method.Specifically,2846 heads were captured in the anthropogenic restoration method,belonging to 86 genera in 48 families of 3 orders,with an average density of The average density of 2,517.69 mites/m2 was2517.69,while the average density of 2,691.97 mites/m2 was 3,043 mites belonging to 3 orders and 53 families,and 89 genera were captured under the natural restoration method.（2）The dominant genera in the two restoration methods were not completely consistent across the rocky desertification class habitats.The dominant genera in each habitat were Perxylobates,Tectocepheus,Parholaspulus,Geolaelaps,Scheloribates and Trichogalumna.Scheloribates,and Trichogalumna,Parholaspulus occurs only under anthropogenic recovery,and Trichogalumna occurs only under natural recovery.（3）The diversity index,richness index,and evenness index of the two restoration methods under the same stone desertification grade were not significantly different（p > 0.05）.The diversity index and evenness index were only significantly different（p < 0.05）between moderate and intense rocky desertification habitats under the same restoration method,and the richness index was only significantly different（p < 0.05）between light and intense rocky desertification habitats under the anthropogenic restoration method.The communities showed moderate similarity or moderate dissimilarity among the habitats under both restoration approaches.（4）The predatory gamasid mites were more abundant in the natural restoration approach（13 families,29 genera）than in the anthropogenic restoration approach（11 families,26 genera）.The MI values ranged from0.14 to 0.39 under the natural restoration approach and 0.13 to 0.46 under the anthropogenic restoration approach.The ecological taxa of predatory gamasid mites were r-selective in both approaches,indicating that both restoration environments were in the process of ecological recovery.（5）There were differences in the composition of oribatid mites（29families and 48 genera）under the natural restoration method and those under the anthropogenic restoration method（28 families and 49 genera）.Both MGP-Ⅰ and MGP-Ⅱ analyses showed that the anthropogenic restoration method had more diverse mite ecological taxa than the natural restoration method,and the mite community types in each habitat in the study area were mainly O-or P-type.The ecological environment was still under restoration.（6）Soil water content,soil capacitance,and soil porosity under two restoration methods of the same rocky desertification class were significantly different only in moderate rocky desertification habitats（p<0.05）,and chemical factors under two restoration methods of the same rocky desertification class,p H was significantly different only in potential rocky desertification habitats（p<0.05）,fast-acting phosphorus was significantly different in potential and moderate rocky desertification habitats（p<0.05）,fast-acting potassium was significantly different only in intensity rock-deserted habitats（p<0.05）,and total potassium and total phosphorus were significantly different only in moderate rock-deserted habitats（p<0.05）.（7）Under the anthropogenic restoration method,fast-acting phosphorus,fast-acting potassium,total potassium,soil salinity and soil capacity were the main environmental factors affecting the distribution of soil mites,with Perxylobates being the most positively correlated with fast-acting potassium,Scheloribates being the most positively correlated with soil salinity,Geolaelaps being the most positively correlated with fast-acting phosphorus,and Parholaspulus being the most negatively correlated with fast-acting phosphorus.Under the natural recovery method,p H,fast-acting N,fast-acting P,fast-acting K,and soil salinity were the main environmental factors affecting the distribution of soil mites,with Scheloribates and Parholaspulus being the most positively correlated with p H and the most negatively correlated with soil salinity.Tectocepheus and Scheloribates were most positively correlated with p H,and Parholaspulus was most positively correlated with soil salinity.（8）Macropylina is often found in less disturbed environments and is more abundant under natural than anthropogenic restoration methods,reflecting soil mites’ recovery speed.Tectocepheus is often found in natural or anthropogenically disturbed,and early successional habitats and is an indicator taxon in the early stages of recovery of rock-desert ecosystems,appearing as the dominant genus under both restoration methods,indicating that the ecosystems in the study area are still recovering.In summary,there were differences in the community composition and distribution of soil mites under the two restoration methods.In terms of composition,natural restoration was more favourable for recovering soil mites,especially predatory gamasid mites.The soil ecological environment in the study area is still in recovery,as indicated by the distribution of predatory gamasid mites ecological taxa and oribatid mites under the restored environment.Continuous follow-up monitoring using multiple methods is needed to reveal better the changes of soil mites in the study area and their correlation with habitat changes. |
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