INTERSPECIFIC INTERACTIONS OF TREES WITH THE REGENERATION OF Ocotea odorifera (Vell.) Rohwer IN MIXED OMBROPHYLOUS FOREST

Resumo

This paper has the purpose to describe spatial interactions among predominant community tree species and seedlings and juveniles of Ocotea odorifera. The raised hypothesis is that some stablished species might attract or repulse Ocotea odorifera seedlings and juveniles in certain distances due to competition, allelopathy, resources sharing or other forms of mutualism or ecological processes. For acquiring spatial data and for floristic and structural characterization we used three nearby sampling units in the same Mixed Ombrophylous Forest (Araucaria Forest) patch. Each plot has 100 x 100 meters. We used the O-ring function (O₁₂), a null model for heterogeneous data, to the bivariate analysis and a test for the spatial independence hypothesis. All tested species presented a significant pattern, indicating that spatial interactions are frequent amongst mature and juvenile plants. Positive and negative interactions occurred in several scales and species. Although the significances were predominant in intervals up to 10 meters, where the negative interactions (repulsion or inhibition) were more frequent. For Araucaria angustifolia, a species that stood out in the community’s horizontal structure, the negative interaction was present up to three meters. We found positive interactions in intervals from six to ten meters. The results showed strong inhibition of seedlings and juveniles by the same family species, suggesting that influences from negative spatial interaction, mainly from parental and with dominant community’s species, may contribute to the processes and generating mechanisms of Ocotea odorifera spatial distribution in local scale.