The role of secondary forests in conserving dung beetle biodiversity in karst ecosystems in Vietnam

Abstract

Although secondary forests comprise half of the world’s
remaining tropical forests, their role in biodiversity
conservation remains poorly known. This study aimed to
evaluate the role of secondary forests in conserving dung
beetle biodiversity in karst ecosystems of Vietnam. In
total, 60 baited-pitfall traps were deployed to investigate
dung-beetle communities in the old secondary forests
(>40 years) and primary forests across two study areas:
Pia Oac National Park (Cao Bang Province) and Pu
Luong Nature Reserve (Thanh Hoa Province). In total,
38 dung-beetle species of 1,266 individuals were sampled
and identified from the trapping sites in the two study
areas. The generalizsed linear models (GLMs) showed
no significant difference in species richness, abundance
and biomass of dung beetles between the old secondary
forests and the primary forests, and this result was
consistent throughout both the study areas. This finding
seemed to give hope for the recovery of dung beetle
communities during forest succession. In contrast, the
community structure still differed significantly between
the primary forests and the old secondary forests
according to the permutational multivariate analysis of
variance (PERMANOVA) (Pia Oac: F=8.92, p<0.001; Pu
Luong: F=6.78, p<0.001). Particularly, a decline in the
number of large-bodied tunnellers in the old secondary
forests might negatively affect the dung removal rate
of the dung beetle communities, being an important
ecosystem function in tropical forests.