How much importance is given to native plants in cities’ treescape? A case study in Fortaleza, Brazil

Abstract

Even though Brazil is a mega-diverse country, many Brazilian cities prioritize exotic plants in their treescapes. Aiming to evaluate how much the treescape in Fortaleza (the fifth largest city in Brazil) is aligned with the policy of valorization of native biodiversity, we sampled street and backyard trees surrounding one of the few vegetation fragments of the city, which is an area considered a priority for conservation. We used the vegetation fragment's flora as reference to compare the potential number of local native species with the actual number of native species in the treescape of the site. To account how much of the native flora was present in the surrounding treescape, we made an inventory of the trees in streets, squares and backyards around the vegetation and compared with the native flora of the vegetation fragment. We then compared the ratio of native to exotic species and checked how many native species of the fragment were also in the surrounding treescape. Exotics were prevalent in both number of species and number of individuals, comprising 70% of the species and 86% of the individuals of public spaces, and 79% of the species and 78% of the individuals of private spaces. Only 14% of the native species of the vegetation were also represented in the treescape, and, in general, they comprehended only a few individuals. We argue that the city's treescape should be re-evaluated in order to value native plants more. Native plants in the treescape could be used as an environmental education tool to publicize native biodiversity to citizens.