Empty forests? A study of land snails from two newly forested areas in the city of Rio de Janeiro (southeastern Brazil)

The concept of ‘empty forests’ is related to places where animal diversity is much reduced if compared with undisturbed sites, mostly caused by hunting/overexploitation and modification of habitat; if this concept is considered in a broad sense, we may include places where major deforestation was followed by reforesting via human hands. We studied the taxonomic composition of land snails from two recently forested areas in the city of Rio de Janeiro (southeastern Brazil), both belonging to conservation units. Beyond the identification based on shell features, DNA sequences were also used to refine the taxonomy of species, in addition to provide important data of comparison for future studies. After fieldwork, 17 species (10 synanthropic, seven non-synanthropic) from 10 families of terrestrial gastropods were found, with 13 species in each conservation unit and Achatinidae as the most diverse family (five species). Low numbers of native and non-synanthropic species indicate that these are depauperate ecosystems, and reintroduction programmes could be applied to enhance ecological processes and restore a typical mollusc fauna. Among the most relevant findings of the genetic investigation, Dysopeas muibum, Helicina inaequistriata and Simpulopsis sulculosa show higher-than-expected genetic diversities, and their taxonomy requires further investigation.