Dispersal restrictions may explain differences in colonization by an invasive tree in Southern Brazil

DECHOUM, MICHELE; REJMÁNEK, M.; CASTELLANI, TANIA; ZALBA, SERGIO M.

Antalya

Congreso; 8th International Conference on Biological Invasions; 2014

Çanakkale Onsekiz Mart University on behalf of NEOBIOTA ? The European Group on Biological Invasions, and in cooperation with other organisations

Short-distance dispersal by frugivorous birds can establish patterns of expansión from existing patches of invasive species. Different management strategies may be required to prevent the arrival of propagules in uncolonized sites. Houvenia dulcis, an invasive tree in forests in South America, native to East Asia, has infrutescenses composed by dark and dry, globose capsuled fruits attached to a brown peduncle which grows thick and fleshy when mature. Birds can carry infrutescenses of H. dulcis to perches in other trees, to peck the fleshy peduncles, facilitating epizoochorous dispersal. In this study, we aimed to evaluate the arrival of H. dulcis propagules at uncolonized sites from patches of invasion at a local spatial scale. The arrival of seeds carried by birds was compared between sites covered in open and closed vegetation in heterogeneous habitats at different distances from patches of the invasive species. Managed areas where the species was cleared were compared with control areas where no action was taken. There is a seed dispersal limitation for H. dulcis at a local scale in the study area associated with the rate and intensity of visitation by frugivorous birds in patches located in the neighborhood of uncolonizad sites. In an attempt to contain the invasion process by H. dulcis in the study area, the main management strategy indicated is the removal of trees with larger basal area located on patch edges. Conflicts of interest generated from control initiatives should be considered in management strategies developed in the region.