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

Abstract

ABSTRACT. Brazilian fauna of drosophilids has been researched in various ecosystems, but those in mangrove forests remain overlooked in Brazil and elsewhere. The present study attempts to characterise the assemblages of drosophilids of this environment, based on 28 collections taken in three mangrove areas in Santa Catarina Island, southern Brazil. The three mangroves surveyed were different in their surroundings, which varied from highly urbanised areas to conservation areas with natural vegetation. Overall, 69 species were collected, and no remarkable difference was detected in species composition and abundances or in the richness, evenness and heterogeneity between sites. The species abundance distribution observed fitted to a theoretical lognormal distribution in the three mangroves. The species richness scored and the performance of the species richness estimators showed an unexpectedly high diversity, considering the very low floristic diversity and the harsh conditions of the environment. Regarding species composition and abundances, the drosophilid mangrove assemblages were shown to be more similar to those found in open environments, with a marked dominance of exotic species. Finally, considering the apparent lack of feeding and breeding sites, we suggest that mangrove forests are acting as sink habitats for the drosophilids populations.KEYWORDS. Biodiversity, diversity measures, Drosophila, Neotropical region, source-sink hypothesis.RESUMO. Assembléias de drosofilídeos (Diptera, Drosophilidae) em manguezais: ecologia de comunidades e diversidade de espécies. A fauna brasileira de drosofilídeos tem sido estudada em vários ecossistemas, mas os manguezais têm sido negligenciados a esse respeito no Brasil e em todo o mundo. O presente estudo traz uma caracterização das assembléias de drosofilídeos neste ambiente, baseando-se em 28 coletas realizadas em três áreas de manguezais na ilha de Santa Catarina, sul do Brasil. Os três manguezais estudados apresentam diferenças marcantes quanto aos ambientes que os cercam, desde regiões altamente urbanizadas até áreas de proteção ambiental com vegetação natural. Ao todo, 69 espécies foram coletadas, e nenhuma diferença marcante foi detectada na composição e abundância das espécies, bem como na riqueza, equitabilidade e heterogeneidade entre os locais. A distribuição de abundância de espécies encontrada ajustou-se a uma distribuição teórica lognormal nos três manguezais. A riqueza de espécies observada e o desempenho de estimadores de riqueza de espécies mostraram uma inesperada alta diversidade, considerando a baixa diversidade florística e as condições hostis do ambiente. A respeito da composição e abundância de espécies, as assembléias de drosofilídeos dos manguezais mostraram-se mais similares àquelas encontradas em ambientes relativamente mais abertos, com grande dominância de espécies exóticas. Finalmente, considerando-se a aparente escassez de sítios de alimentação e oviposição do ambiente, sugere-se que os manguezais estejam agindo como "sink habitats" para a...

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

“…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.…”

Effects of seasonality on drosophilids (Insecta, Diptera) in the northern part of the Atlantic Forest, Brazil

“…Approximately 80% of the richness of the drosophilid assemblage analysed was formed by rare species, which are represented by those whose frequency is below 1%. This pattern is regularly observed for Neotropical arthropods (Novotny & Basset, 2000; Coddington et al ., 2009), and it has been described in studies about drosophilids from the Atlantic Forest (Schmitz et al ., 2010, Cavasini et al ., 2014) and other biomes, such as the Amazon Forest (Acurio et al , 2010), the Cerrado (Roque et al ., 2013) and the Caatinga (Oliveira et al ., 2016). From the ecological and evolutionary standpoints, rare species are those that have become more specialized to a few environments (Dobzhansky & Pavan, 1950).…”

Phenology of Drosophila species across a temperate growing season and implications for behavior

“…[19–22]), the majority of studies of community assemblage have been conducted in the tropics (e.g. [23, 24]). In disturbed areas of the tropics, exotic species dominate and displace native species [17, 23–26], a pattern also seen in temperate zones [27].…”