Macrofauna insectil epiedafica en sabanas y forestaciones con Acacia mangium Willd., en un núcleo forestal de la Orinoquia

Abstract

The afforestation of savannas in areas of the Colombian Orinoquia implies a drastic change in the structure of the vegetation that can be reflected in the modification of the biodiversity of soil arthropods. In this study, epiadphic insect assemblages were compared in Acacia mangium Willd forest plantations. of three ages (1, 3 and 5 years), gallery forests and Savannahs (previous use of the soil) in a nucleus of commercial forest plantations located in Puerto Gaitán, Meta. Sampling was done with pitfall traps in the wet season and in the dry season of 2015 and then the effective diversity of families of order q0, q1 and q2 was estimated and compared. Beta diversity was estimated with the Bray & Curtis method to compare the similarity of families between the coverages compared. Likewise, to explain the diversity of families based on some soil and dasometric dasometric variables, a redundancy analysis (RDA) was carried out. 12,461 insects belonging to the macrofauna of the soil were collected, grouped into 57 families. The most abundant order was Hymenoptera, followed by Coleoptera, Hemiptera, Diptera, Ortoptera and Blattodea. The greatest wealth of families was found in La Sabana (32), followed by the plantations of A. mangium of 5 years (32), Gallery Forest (29), A. mangium of 1 year (27) and finally A. 3 years old mangium (23). It was also observed that the dry season severely affects the abundance of the ephemeral insects at the study site. The RDA analysis showed an important relationship between the Myrmicinae family and the nitrogen content in the soil. The similarity of the communities clearly showed the difference between the savannas and the arboreal ecosystems, however with families that were in both coverages. The results of this work are considered important inputs for the planning of sustainable forest management in relation to the associated diversity in the plantations.