Pine processionary caterpillar is a pest that does not survive very low temperatures and that is spreading through our country and the Mediterranean. In an article published in the journal Biodiversity and Conservation by José Antonio Hódar Correa and Regino Zamora Rodríguez, teachers of the Department of Animal Biology and Ecology of the University of Granada, the predictable consequences of climate warming in the Scots pine of Sierra Nevada are analysed. Such species is beginning to be a habitual food for processionary caterpillar.
Scots pine is a northern species, and the southernest place it lives in is precisely Sierra Nevada. As regards processionary caterpillar, it is a moth larva which develops in winter. Although it attacks many pine species, in Sierra Nevada it usually stands on Austrian pines (Pinus nigra), a Mediterranean and mountain species. This tree usually grows between 800 and 1,600 metres high, where temperatures are appropriate for procesionnary caterpillar. More to the north, where Scots pine grows, temperatures would be too low for it to survive.
In this sense, UGR researchers have observed that the climate change is producing an increase in the presence of processionary caterpillar in Sierra Nevada, with negative consequences for pines. “So far, there were places where it was almost impossible for larvae to develop. Now, it is getting possible because winter temperatures are higher”. We have started to see moth bag shelters (a mechanism of processionary moths to remain warm) in Scots pines 2,000 metres high.
Forest policy
The pest will settle in this areas if there are pine species liable to suffer from processionary caterpillar. But, given the wide diversity of tree species that have traditionally grown in the sierra of Granada, which should not be the case. It is due above all to the existence of big homogeneous pine reafforestations fruit of the forest policy, “which has not always been appropriate and to an inadequate forest mass management”, according to Hódar.
Thus, appart from fighting against global warming, the UGR researcher points out that we must rethink “the current structure of many pine reafforestations”. And he concludes: “In Sierra Nevada some pine woods are being thinned out to promote olm oaks”. A difficult task with long-term effects.
Reference:
Prof. José Antonio Hódar Correa.
Phone number: 958 243242.
E-mail: jhodar@ugr.es
