Analysis of the ground Coleoptera communities of agro-ecosystems within the Oriented Natural Reserve Pino d Aleppo (Ragusa, Sicily) and their use for assessing the environmental quality

Abstract

Recent studies showed that increasing or maintaining a high level of biodiversity in agriculture depend not so much on the reduction of conventional farming practices but rather on other factors, where the most significantly appears to be the patchy structure of landscape. In the Mediterranean area, human activity has dramatically reversed the relationship between open spaces and forests, reducing the latter to fragments inserted in a matrix profoundly changed: in flatland and hilly areas the extension of the forest has been drastically reduced and they are now comparable to islands more or less large. The Pino d Aleppo Natural Reserve, where the present research was conducted, shows a typical situation: a mosaic of natural and semi-natural habitats fragmented and isolated at various degree, within an environmental matrix strongly modified by human actions, first of all the intensive use of land for agricultural activities. This research concerned the study of ground Coleoptera communities of three different agro-ecosystems: Arable land with Carob trees (AC), Olive grove (Ol) and Citrus grove (Ci) and of a residual patch of Mediterranean maquis (Tk) investigated by pit-fall traps. Therefore, the study focused on Coleoptera, for which has been developed the examination of Families, with particular reference to species of Carabidae, Tenebrionidae and Staphylinidae (excluding Aleocharinae). Inside each station five pit-fall traps have been installed filled with a solution of water, vinegar and table salt in saturation; the gatherings of the pit-fall traps took a year from June 2009 to July 2010. The results obtained have been compared with the data of a previous research conducted from July to December 2007 using the same method within the same area in different habitat typology: 3 natural Pinus halepensis woods, 1 maquis, 2 garrigues, 1 meadow, 1 artificial Pine reforestation (BOCCHIERI 2009). With regard to the single family of Coleoptera Carabidae, it was developed the index for fauna value (INV) (in BRANDMAYR et alii, 2005) for each of the 12 patches studied, transferring than the value of this index on computerized cartographic support (GIS platform) to process of thematic maps elaboration. The study has underline that: 1) Three species are new for Sicilian fauna: Microlestes fissuralis (Reitter 1901), Pterostichus (Platysma) niger niger (Schaller 1783) e Micropeplus porcatus Paykull 1789. 2) The biodiversity of ground fauna occurs with different aspects depending on the stations and groups considered. 3) Biodiversity is distributed in different temporal domains. 4) The biodiversity of ground fauna observed within the investigated agro-ecosystems is not as high on average, both for Families and for the species complex of Carabidae, Tenebrionidae and Staphylinidae, than that found in natural habitats within the same area. 5) The stations differ significantly in community structure at any level they are investigated. 6) The contribution of this biodiversity, and the stability of agro-ecosystems remains to be defined. 7) In prospect of a correct land management, considering that the land investigated is a protected area, the patches should be protected to maintain significant levels of biodiversity.