Canvis en la comunitat de coleòpters de vegetació a causa d'un incendi forestal al Parc Natural de Sant Llorenç del Munt i l'Obac

In the Mediterranean Basin, fires have played a
key role in the landscape structure and in the
composition of organism communities. In the
future, it is expected that this disturbance
increases in terms of extension and frequency,
thus affecting the maintenance of biodiversity in
the Mediterranean natural reserves. In this work,
we have analyzed the response of vegetation
beetles after a wildfire occurred on August 2003 in
the Parc Natural de Sant Llorenç del Munt i
l'Obac. In the spring of 2007, a sampling program
with sweep net was conducted in a total of 24
sampling stations, which included a control area
(not burnt) and four areas with different post-fire
management practices. Alpha (Margalef index,
uniformity and Simpson) and gamma diversity
measures (total number of species in the study
area), and multivariate analysis (Principal
Component Analysis) were calculated using the
abundance of species of beetles at sampling
stations. A total of 876 specimens of beetles
belonging to 75 species were collected. The
results showed a general increase in abundance
and species richness in the burned areas compared
to the unburned forest, as well as an increase of
gamma diversity. The commonest species in control
forested sites became scarce or extinct in
burned sites. Furthermore, we observed many
exclusive species from a single area (33). The
increase in the total number of species (gamma
diversity) and the high number of exclusive
species could be caused by habitat heterogeneity
(forest versus open-areas) and also by differences
among burned sites due to the application of
several post-fire management. Our study supports
the general idea that landscape heterogeneity may
cause high levels of biodiversity in Mediterranean
ecosystems.