Entre nuvens e plantas: galhas nas florestas nebulares

Abstract

Galls are characterized as alterations that occur in plant tissues, generating cellular hypertrophy and tissue hyperplasia. The formation, richness, and diversity of galls are directly linked to the diversity of the local flora, due to the species-specific relationship between the gall-inducing insect and the host plant, which is determinant for the existence of specific morphotypes. The objective of this study was to inventory the diversity of galls in a cloud forest, analyzing how variations in altitude, temperature, and soil influence this diversity along an altitudinal gradient (elevations of 1700, 1900, 2100, 2300, and 2500 meters). The work sought to answer the following questions: 1- Does altitude, as an ecological filter, influence the diversity (richness and uniformity) of galls present in the cloud forest environment, and does it differ from other domains? Are galls good bioindicators of ecosystem quality in relation to altitude variation? Is there a pattern in the morphotypes observed at different altitudes compared to other domains? The study area is located in the Itatiaia National Park, encompassing the municipalities of Alagoa, Bocaina de Minas, and Itamonte, in the Serra da Mantiqueira mountain range, Minas Gerais, Brazil. The region is characterized as a Cloud Forest of the Atlantic domain, with mountainous terrain and altitudes reaching 2791 meters. Collections were carried out monthly over 12 months at five altitudinal levels, using nine permanent plots of 400 m² each. Sixty-one host plant species and 86 distinct gall morphotypes were identified. The results revealed that the diversity of host plants and gall morphotypes decreases as altitude increases, varying from 26 morphotypes at 1700 m to only 8 morphotypes at 2500 m. Some species exhibit more than one gall morphotype, especially at intermediate altitudes. The morphotypes studied presented tissue neoformations, processes of hyperplasia and cellular hypertrophy, in addition to the disorganization of the original chlorophyll tissue of the host. The study concludes that altitude, along with edaphic and climatic characteristics, plays a fundamental role in the distribution of galls, acting as a modulating factor in the environment. Thus, galls are confirmed as excellent bioindicators of ecosystem quality and environmental variations in cloud forests, due to the appearance of gall morphotypes in indicator species of montane forests, and their conservation is essential for maintaining the biodiversity of the Atlantic Forest.