A 10-year evaluation of the functional basis for regeneration habitat preference of trees in an African evergreen forest

The spatial distribution of tree juveniles in relation to light environments may reflect species differe in growth, survival, and functional traits and will shape the nature of forest regeneration. Long-term experiments are important to evaluate this issue because of the potentially very long juvenile perio trees. Here, we combine a 10-year seedling survival–growth data with the results of commu ordination and multivariate analyses of functional traits to ask how observed juvenile light guilds related to species functional traits and seedling performance. We transplanted seedlings a standardized height of 11 cm into the shaded understory and quantified their growth and surv for 10-year. Using the community-wide stem distribution data, we categorized 33 species including focal 11 species to understory vs. gap/edge guilds. Then, we determined differences between the guilds in seedling survival, growth, as well as seed size, adult height, and a series of leaf traits, inclu toughness and chemical traits (fiber, protein, phenolics, tannins, alkaloids, saponins). Among the 11 n pioneer species whose seedlings were planted into the understory, there was no significant differenc 10-year survival between light guilds, but species in gap/edge guild tended to achieve greater height t species in the understory guild. The leaf chemical traits of 33 species did not differ between the juvenile light guilds, but gap/edge species had smaller seeds, taller adults, and tougher leaves t understory species. We used logistic regression as a complementary approach to assess the exten which plant traits varied between light guilds and the most parsimonious model based on AICc ran included only leaf toughness and had an Akaike weight of 0.52. In addition, across the 11 species plan as seedlings, these traits were not significantly related to survivorship or growth over 10 year Principle Components Analysis illustrated associations among traits. We conclude that light guild terms of juvenile stem distribution could not be explained by long-term field performance of p establishment seedlings alone. Earlier seedling stage or later sapling stage may be more importan differentiation of light guilds. For the species examined difference in growth rates could be linked to s size and adult stature, but not to the adult leaf chemical traits considered. These results suggest importance of examining ontogenetic shifts and relationships among functional traits for a be understanding of regeneration strategies of tropical trees. 2008 Published by Elsevier