Assessment and Monitoring Damage by Coraebus florentinus (Coleoptera: Buprestidae) in Mediterranean Oak Forests

The environmental degradation of the Mediterranean forests is an increasingly considered question when designing the management measures dealing with biodiversity or climate change.

Coraebus florentinus is a xylophagous jewel beetle (Coleoptera: Buprestidae), which bores the branches of different species of Quercus. Because of its affinity by holm (Quercus ilex, Linné 1753) and cork oaks (Q. suber, Linné 1753), this insect is mainly distributed in the Mediterranean forests where these tree species predominate. And the damage is mainly due to the feeding activity of the larvae which cuts the sap flow into the branch where it develops, drying it. In the last decades, the geographical range and the damage records of this species have expanded northwardly as a result of the climate global change since warmer conditions favor higher reproduction and quicker development of this species.

In this paper, historical series of data after ten years evaluating damages by C. florentinus in Hornachuelos Natural Park (Southern Spain) were analyzed under the perspective of the environmental temperature increase linked to the global climate change. The assessment was done between 2007 and 2017, in two sampling plots of Mediterranean mixed-oak forests where holm and cork oaks are the predominant tree species. The foreseeable rising of damages of C. florentinus was also discussed, at greater scale, under the perspective of future scenery of environmental warming and oaks decaying by losing fitness due to higher soil aridity.

Results showed that the infestation levels of this species at the beginning of the assessment period were higher than those described previously in the nineties and that they increased progressively during the monitoring time. The results also agreed with the expansion of its distribution areas noticed in other areas of Europe. In conclusion, based on the current results and those of prior research, it can be stated that there has been a local thermal increase that has affected the populations of C. florentinus in the southern Iberian Peninsula, extending their damage but not intensifying them significantly. Besides, the foreseeable spreading of the insect on the future climate scenarios makes necessary the implementation of effective control activities, as selective pruning, in the management of Mediterranean oak forests, as a preventive measure to avoid the demographic explosion of this pest.

Article by Ana M. Cárdenas and Patricia Gallardo, from University of Córdoba, Córdoba, Spain.

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Image by Alain C., from Flickr-cc.