Functional patterns of tree communities in natural Araucaria forests and old monoculture conifer plantations

A functional perspective of tree communities is helpful for understanding forest dynamics, especially vegetation recovery after other land uses. Knowledge about ecological filters and survival strategies of trees are also important for the restoration of degraded areas. This study aimed to evaluate the functional composition and structure of adult and regenerative components of natural Araucaria forests, Araucaria plantations and plantations of exotic Pinus in subtropical southern Brazil. Differences in functional diversity and functional richness, and in community weighted mean trait values, including leaf traits and reproductive traits, were analyzed. RLQ analysis was used to assess the association between community structure, plant traits and environmental variables. Clear differences were found for most traits and for functional richness for the regenerative component, while the adult component was more similar among forest types. A clear separation in RLQ ordination associated with trait variation, for the adult component but not for regenerative trees, also indicates that communities are becoming functionally more similar with time. Plantations were shown to function as environmental filters by directly influencing species recruitment, richness and functional diversity. We conclude that passive restoration may be the best strategy for restoration of Araucaria forests.