Study of the Drosophilidae (Diptera) communities on Atlantic Forest islands of Santa Catarina State, Brazil

Abstract

A study of the community dynamics of Drosophilidae was carried out in six insular communities and two others on the mainland. Seasonal collections were carried out throughout two years in Santa Catarina State, southern of Brazil. The diversity index calculations show high values when compared with temperate climate communities. The sites on the mainland (Serra do Tabuleiro) presented the highest diversity, which was measured by the Diversity Index (H'). These sites are covered by primary Atlantic Forest and theoretically should have a higher variation of ecological niches. A dendogram showing the similarity between the communities, calculated by Morisita Index, points to a level of similarity equal to 60% for all communities. In this diagram, we can see two clades: one on the mainland and the other on the islands. The six island sites are grouped into one clade and separated into two subclades, one including the sites on Santa Catarina Island and the other consisting of the islands adjacent to this last and very much larger one. These groupings show the very important role of the spatial component on the prediction of the structure of the communities. This fact raises the discussion about the high complexity of the Atlantic Forest ecosystem and consequently the unpredictability of its fauna, highlighting the need of its conservation.

Comparison of Drosophilidae (Diptera) assemblages from two highland Araucaria Forest fragments, with and without environmental conservation policies

“…Thus, significant seasonal correlations between years and areas of collection of drosophilids with climatic data were considered only for species that had N ≥ 30 in at least one area Therefore, changes in the drosophilid assemblages, in general, cannot be related to the climatic alterations detected between years. However, is noteworthy to point out some consistent changes for a couple of species, such as: D. polymorpha was collected with higher abundance in the warmer seasons (summer and spring), in agreement with the correlation analysis above; the exotic species D. kikkawai and D. simulans were also more abundant in warmer seasons; D. mediopunctata was more abundant in 2008 autumn and winter in both areas; and the subgroup willistoni was more representative in summer and autumn in PMA and in summer in FBL (Table 1-SM -supplementary material), in agreement with several authors (Patterson, 1943;Dobzhansky and Pavan, 1950;Franck and Valente, 1985;Toni et al, 2007).…”

“…Among the Neotropical indigenous species, the subgroup willistoni showed differences of more than 70% between areas (Table 3) Regarding the ecological indexes, PMA in 2006 (H' = 2.601) and the autumn in 2006 in both areas (PMA: H' = 2.941; FBL: H' = 2.626) had higher diversity than already detected, but in general, the diversity indexes (H') were mostly similar (but sometimes higher than) to those found in other works (Silva et al, 2005a;Tidon, 2006;Toni et al, 2007;Gottschalk et al, 2007;Bizzo et al, 2010;Schmitz et al, 2010;Poppe et al, 2012). No seasonal pattern was detected in both areas.…”

Assemblages of drosophilids (Diptera, Drosophilidae) in mangrove forests: community ecology and species diversity

“…Even in the willistoni group, the most common species in the mangroves were D. willistoni and D. paulistorum (willistoni subgroup), which, in spite of being more abundant in the forests (SAAVEDRA et al, 1995;TIDON, 2006), are still the most abundant of the group also in other environments (SILVA et al, 2005;TIDON, 2006). In addition, D. nebulosa, the only species of bocainensis subgroup that prefers open environments (VAL et al, 1981), was more abundant than other species of the subgroup, an inverse situation found by DE TONI et al (2007) in the Atlantic Forest. Despite being a forest, probably the mangrove forests should be more appropriately interpreted as xeric environments.…”

“…Together, the exotic specimens accounted for 83% of all specimens captured, and were dominant not only for a mangrove situated within an urban zone, but also for one located in a conservation area with native vegetation. These species also dominate in the urban environments (FERREIRA & TIDON, 2005;SILVA et al, 2005;GOTTSCHALK et al, 2007), as compared to those from the Atlantic Forest, where they are replaced by native species, especially those of the willistoni group (SAAVEDRA et al, 1995;DE TONI et al, 2007). The urban zones may be characterised as open, well-lit and xeric environments.…”

“…The Brazilian drosophilid fauna is highly diverse (SENE et al, 1980;VAL et al, 1981), and has been researched in different types of environments. The heterogeneous nature of Santa Catarina Island, in southern Brazil, has been surveyed as an opportunity to compare drosophilid assemblages in different environments of the same region, especially the Atlantic rainforest and the urban environment (DE TONI & HOFMANN, 1995;DE TONI et al, 2007;GOTTSCHALK et al, 2007). In this context, in a previous study (SCHMITZ et al, 2007), we conducted a taxonomic survey of the Drosophilidae fauna present in the mangrove forests of Santa Catarina Island, an environment not surveyed before anywhere.…”