Traits of shrubs in forests and bushes reveal different life strategies

Aims Shrubs play important roles in both forest and bushland ecosystems. This study aims to identify the adaptative strategies of shrubs in different habitats by analyzing the differences in functional traits of shrubs grown in understory of forest communities and in two bushlands.Methods Nine functional traits for leaves and twigs were measured on samples collected from the dominant shrub species in 24 plots distributed in three contrasting habitats: forest understory, low mountain bushes, and bushes on the mountaintop, in Beishan Mountain of Jinhua, Zhejiang Province. The overall differences among habitats, inter- and intra-specific variations, and differences between life forms in the functional traits of shrubs were tested by statistical analysis.Important findings The nine plant traits differed for shrubs grown in the three habitats. The shrubs in forest understory had higher leaf area (LA) and specific leaf area (SLA), lower leaf dry-matter content (LDMC), leaf tissue density (LTD) and twig tissue density (TTD), while those in low mountain bushes had greater leaf thickness (LT) and LTD, smaller SLA and twig dry-matter content (TDMC), compared with shrubs from bushes on the mountaintop. The inter- and intra-specific variation coefficients of SLA, twig diameter (TD), TTD, and TDMC were greatest in shrubs of the forest understory, whereas the inter- and intra-specific variation coefficients of SLA, LDMC, TDMC, and TTD were smallest in ??shrubs of low mountain bushes. Among different life forms, the understory evergreen shrubs had significantly higher LT, LTD, and LDMC, and lower SLA, than that of deciduous shrubs. The differences in LT and SLA between evergreen and deciduous shrubs of the mountaintop bushes were the same as the understory shrubs, but the differences in LTD and LDMC were reversed. Species and its interaction with habitat are the major factors affecting the shrub traits. In short, compared to the shrubs from bushes, the understory shrubs in forest communities form a series of trait combinations with greater LA and SLA, and smaller LTD, TTD and LDMC for faster growth in order to adapt to the understory environment with less light and stronger competition; this is a quick investment-return (resource acquisitive) strategy. Shrubs from low mountain bushes and the mountaintop bushes are associated with a series trait combinations with greater LT, LTD, LDMC and TTD, and smaller LA, SLA for storing more nutrients and growing slower; this is a slow investment-return (resource conservative) strategy. Different combinations of shrub functional traits and their various life strategies can provide guidance to the ecological restoration of degraded vegetation in the subtropical region of China.