Forest succession and distance from preserved patches in the Brazilian semiarid region

Preserved vegetation fragments can serve as islands or germplasm banks that aid in the recuperation of anthropogenically degraded areas. The present study evaluated the effects of the distance to a preserved forest fragment on the recuperation of an abandoned agricultural field that had been naturally regenerating for 15 years in Caruaru, PE, Brazil. Seven 240 m transects were laid out perpendicular to the border between the abandoned field and preserved forest fragment, and each transect was divided into twelve 5 × 20 m contiguous plots, thus forming 12 bands at progressive distances from the preserved site. The height and diameter of all live individuals within each plot with a stem diameter ⩾3 cm at ground level were recorded. At the community level, the number of individuals, their average heights and their maximum diameters did not demonstrate any statistically significant relationship with increasing distance from the preserved vegetation fragment. Only a few species demonstrated any relationship between the distance to the preserved fragment and density, basal area or ecological importance. The anthropogenically altered area had higher numbers of individuals of autochoric species than the numbers of anemochorous and zoochoric species. The relatively long period of abandonment of the area apparently masked part of the role of the preserved forest fragment in restoring the altered area through dispersal because some species could have sprouted from cut stems, while others could have germinated directly from the soil seed bank. The species Croton blanchetianus and Cordia trichotoma were identified as principal colonizers in the initial phases of succession.

► Preserved vegetation fragments can maximize the recuperation of degraded areas.
► Tests on the effects of the distance of a fragment on recuperation of a degraded area.
► Few species were influenced by the distance to the preserved fragment.
► Altered area has higher number of autochorous species.
► Period of abandonment apparently masked the role of the forest.