Richness of gall morphospecies along a secondary successional gradient of Atlantic Forest in northeastern Brazil

Abstract

Galling insects have been recommended as an excellent tool to evaluate environmental changes and habitat quality. In this study, we assessed the richness of gall morphospecies, as well as host-plant richness and abundance, to detect environmental changes in six patches of secondary Atlantic Forest in Northeast Brazil. The patches of forest varied in age (between 25 and 42 yrs) and size. In each patch, the plants between 1 and 3 meters tall were evaluated for a period of one hour, totaling six hours. A total of 50 gall morphospecies were found on 37 host-plant species (88 plant individuals). We identified 27 (72%) host-plant species belonging to 19 plant families. Richness of gall morphospecies and host-plant richness and abundance were not significantly affected by the age and size of the patch. However, the richness of gall morphospecies increased significantly as the host-plant percentage of shade-tolerant trees increased. Considering that the differences observed in this study, between younger and older patches, developed in a relatively short time period of forest recovery (c. 18 yrs), and that some host-plant species occurred exclusively in older patches, this study showed that gall-inducing insects are a good tool for evaluating changes in a secondary successional gradient. The use of gall-inducing insects as bioindicators in restoration and conservation programs is not only a good opportunity to advance this type of study but is also a useful application, at local and regional scales, to monitor the successional progress of forests.