SPATIAL BIODIVERSITY OF EPIGEAN ARTHROPODS IN AN OLIVE GROVE IN SOUTHERN IBERIA

Abstract

This study aims to observe the spatial distribution of the arthropods biodiversity inhabiting the soil surface of olive groves. For this purpose, a sampling campaign has been carried out in a 15.1 ha plot of this crop. This plot is located in the south of the Iberian Peninsula. The study comprised a total of 65 sampling stations for epigean arthropods. Each station consisted of two drop traps, one located under the canopy of the olive tree and the other in the middle of the strip. With the arthropod catch data from each sampling station, the Shannon biodiversity index per sampling unit was calculated. The average of the 65 stations amounts to a biodiversity value of 1.66 for this index. It can therefore be considered to have a relatively low diversity. This is a normal result in cultivated systems. A study of this biodiversity index has also been carried out for the three most important orders of soil-dwelling arthropods: Coleoptera, Hymenoptera and Araneae. In these orders, very low biodiversity values were found, as the number of species counted was reduced. Respectively, the results were 0.49, 0.68 and 0.61. Subsequently, a kriging study was carried out to study the distribution patterns of the results obtained at the sampling stations. The patterns show a general enrichment in biodiversity from the highest and steepest enclaves to areas of lower altitude and lower slope. With respect to biodiversity within the three orders studied, the patterns have not been as evident. Particularly in the case of Araneae.