Germination performance of the invader Leucaena leucocephala (Lam.) de Wit. compared to Caesalpinia ferrea Mart. ex Tul. and C. pulcherrima (L.) Sw. (Fabaceae)

(Germination performance of the invader Leucaena leucocephala (Lam.) de Wit. compared to Caesalpinia ferrea Mart. ex Tul. and C. pulcherrima (L.) Sw. (Fabaceae)). Success in establishing and colonizing new areas is directly related to germination behaviour of seeds under local environmental conditions. This work aimed to compare germination performance of the exotic invader Leucaena leucocephala to two legumes (Caesalpinia ferrea, native, and C. pulcherrima, exotic) which are not considered invasive. Non-scarified seeds were exposed to constant temperatures of 15, 20, 25, 30,35 and 40 degrees C, within a photoperiod of 12 hours, for 100 days. Both final germination percentage and germination speed showed significant differences among the three species. C. ferrea had low germination percentage, with optimal germination temperature at 25 degrees C, reaching germination percentage of 59% and germination speed of 0.68 seeds d(-1). In contrast, C. pulcherrima had high germination percentages at all temperatures tested, with highest germinability from 20 to 40 degrees C. Seeds of L. leucocephala had the lowest germination percentage and optimal germination temperature was 35 degrees C. The germination performance of this exotic is not outstanding, and factors such as propagule pressure, natural scarification and good performance in other life stages must contribute to its invasiveness.