Diversity and seasonal changes in carabid assemblages of a mature, secondary and plantation forest mosaic in the Zhangguangcai Mountains in northeastern China

While China is promoting the re-establishment of forests across the country on a globally unprecedented scale, the biodiversity harboured by the resulting secondary and plantation forests remains poorly understood. Here, we assess the carabid diversity at Zhangguangcai Mountains in northeastern China that comprise a unique mosaic of mature forest remnants, secondary forests and forest plantations. We located pitfall traps in five distinct forest types: mature conifer and mature mixed forest, secondary mixed forest, secondary broadleaved forest dominated by birch (Betula platyphylla) and poplar (Populus davidiana), and in larch plantations. We recorded 9073 carabid beetles representing 42 species, with richness, abundance and diversity of ground beetles all peaking in secondary broadleaved forests. Assemblages sampled in larch plantations were least species rich, but species extrapolation curves indicate a potentially high overall species richness. Carabid communities were clearly differentiated according to forest type, with larch plantations and secondary broadleaved forests containing beetle assemblages distinct from the other three forest types, while the mixed secondary and mature forest types harboured similar assemblages. Carabid communities also showed a clear seasonality in all forest types, with the plantation forest communities remaining distinctly different from the clustered communities of the mature and mixed secondary forest types throughout the year. Broadleaved secondary forest assemblages occupy an intermediate position throughout the sampling season.