Patterns of mistletoe infestation in neotropical urban areas: Fid-Bau Portal

Patterns of mistletoe infestation in neotropical urban areas

de Menezes, Marcelo Oliveira Teles / Moro, Marcelo Freire / de Souza, Marina Oliveira / de Almeida, Jorhan Marinho / de Freitas Braga, Dávila Vitória / de Alencar, Pedro Lucas Rodrigues / de Araújo, Francisca Soares

Abstract

Abstract Mistletoes occur in tropical and temperate ecosystems all over the world. In urban areas mistletoes can become weedy and affect the health of cultivated trees. In this study we sought to detect patterns of infestation at tree, species, and community level, in order to support improvements in urban tree planting policies. Field studies were performed in Fortaleza, CE, Brazil. The trees and their mistletoes were surveyed in four green areas to examine the relationship between the severity of the infestation and tree attributes (trunk diameter, nativeness, and distance to the nearest infested tree). We evaluated the prevalence, the severity, and the preference ratio (PR) of each tree species according to their respective abundance. We also compiled data from other studies carried out in different cities in the Neotropical region, between 20º N (Mexico) and 32º S (Southern Brazil), to evaluate the relationships between prevalence and three urban tree community attributes (tree species richness, % of exotic trees, and tree density). Due to the high number of independent variables analyzed and their non-normal distribution, we used the Generalized Linear Mixed Model approach (GLMM) and the Spearman’s rank correlation coefficient to evaluate the relationship between all mentioned variables and mistletoe indicators. We were able to generate models with significant estimates for prevalence and severity of mistletoe infestation. We evaluated the GLMM through the AIC, the BIC, and the dispersion parameter. We also found significant correlation coefficients between prevalence/severity and all independent variables (except for tree density). We found that bigger trees and those near to previous infestations tend to be more infested. Exotic species showed higher PR, higher prevalence, and higher severity. At the community level we found that a high tree species richness and a low percentage of exotic trees are associated with a low prevalence of mistletoes. Our results bring a new point of view to urban forestry, urban ecology, and management of urban green areas. We propose that tree planting in urban areas should aim for high diversity with a low percentage of exotics.