First data on soil collembola in super-high density and traditional olive orchard management systems

Abstract

The Collembola community plays an important role in soil ecosystem services. The aim of this study is to provide the first data on the soil Collembola communities occurring in three different olive orchards located in Sicily (Italy), one traditional and two super-high density systems. While the same fertilization management and phytosanitary measures were applied, soil management in the two super-high density systems consisted of green manure, and conventional tillage was adopted in the traditionally managed olive orchard. Nine soil samples per orchard were collected in the first week of October 2019, and the arthropod fauna was extracted using a modified Berlese-Tullgren funnel. Collembola were counted and identified at morpho-species level, and at least one specimen for each morpho-species was slide mounted for species identification. Soil Collembola communities were evaluated using the abundances of identified species and eco-morphological life forms. Besides, soil biological quality was investigated using the QBS-ar index. Overall, 22 species belonging to nine families were identified. The mean number of springtails per soil sample was lowest in the two super-high density orchards, while the total number of species does not show a noticeable variation among the three olive orchards. An average similarity at the species level of 59.95 % was found between the two super high intensive orchards, that showed a lower average similarity with the traditional olive orchard (44.39 % and 50.23 %). Regarding the eco-morphological life form groups of Collembola, the Atmobionts were present only in the traditional olive orchard, Hemiedaphic and Epedaphic life forms were most abundant in the traditional olive orchard, while Euedaphobionts were the most represented in all olive orchards. Moreover, the exclusive Collembola species in the two super high intensive orchards were Euedaphic and Epedaphic life forms, while the exclusive species recorded in the traditional olive orchard belonged to all life forms, with a prevalence of Euedaphic springtail species. The sharing of the only Epedaphic and Euedaphic life forms between the two SHD olive orchards confirms that the intensive management system negatively affects the Collembola of the Atmobiotic life forms. Hemiedaphic life forms were affected to a lesser extent, since they are influenced mainly by microhabitat diversity in the upper soil layer. Furthermore, the negative effects of the more intensive management system influenced the QBS-ar index values, indicating that intensive management influences mainly soil surface taxa, like the predators Chilopoda and Pseudoscorpiones. However, our preliminary study suggests that conservative and sustainable soil management can maintain or improve the arthropods and Collembola community’s soil functionality, although further studies are needed to assess the role of the other agroecological factors.