Soil seed bank of caatinga invaded by Cryptostegia madagascariensis Bojer ex Decne.

Abstract

The establishment of invader exotic species such as Cryptostegia madagascariensis Bojer ex Decne. often causes adversative changes for the environment, which may change the vegetation characteristics through the disappearance of native species of different growing habits. The objective of this study was to investigate the influence of the invasion by Cryptostegia madagascariensis on diversity the soil seed bank in a remnant of Caatinga, in Ibaretama municipality, Ceará, Brazil. The ambient was divided in two areas: Not Invaded Area - Ambient I (remaining of Caatinga well conserved relatively); and Invaded Area - Ambient II (characterized by having significant invasion of Cryptostegia madagascariensis). It was collected 50 soil samples, randomly, at each allocated area. We evaluated the floristic composition, diversity and vegetation structure. Germination was recorded thru the study of 5.930 individuals, distributed in a total of 18 families, 46 genres and 71 species. The diversity for Non-invaded and invaded areas was 3.22 and 2.54, respectively. The lowest diversity observed for the Invaded Area shows that the significant presence of Cryptostegia madagascariensis tends to reduce the specific floristic composition of the soil seed bank of invaded area.