RESUMO
A comparative study on forests and grasslands in three ecoregions (Humid Chaco, Espinal, and Paranaense) was conducted in two protected areas in northeastern Argentina: Iberá National Park and Mburucuyá National Park. The effects of habitat heterogeneity (vegetation cover) on terrestrial ant (Formicidae) assemblages were analyzed and compared. The habitat heterogeneity hypothesis-which predicts that when environmental structural complexity increases, the species richness will also increase-was tested. Two sites were selected in each ecoregion. A forest and a grassland were surveyed in each site, using unbaited pitfall traps from October 2013 to February 2014. Overall, 5,465 ants belonging to 37 species were collected, 32 of which were present in forests and 26 in grasslands. Solenopsis invicta Buren (Hymenoptera: Formicidae) and Pheidole radoszkowskii Mayr (Hymenoptera: Formicidae) were the most abundant species. Formicidae assemblages were compared in terms of abundance, species richness, and diversity between habitats and ecoregions. The results of this study support the habitat heterogeneity hypothesis, since we found a higher diversity of ants in more structured habitats (i.e., forest) in the three ecoregions analyzed. Also, the ant assemblages differed both between habitats and between ecoregions. Our findings provide the first assessment of terrestrial ant assemblages in natural habitats of the three ecoregions in Corrientes Province, Argentina.
Assuntos
Formigas , Animais , Argentina , Ecossistema , Florestas , PradariaRESUMO
Sarcophagidae (Diptera) are of great interest from a veterinary, medical, and forensic viewpoint, and are potential bioindicators for environmental impact assessments. In this study, we evaluated changes in abundance, species richness, and diversity of flesh flies in different habitat types in the Humid Chaco ecoregion of South America: 1) anthropized habitats: urban, cattle farm, and alfalfa crop, and 2) natural habitats: savanna and forest. We hypothesized that sarcophagid fly community parameters are affected by the anthropization and that spatial turnover will contribute more to the overall beta diversity than nestedness between habitats. In each habitat, samplings were conducted monthly from March 2015 to February 2016 in 25 sites, 5 per habitat, totaling 300 independent samples at the end of the study. We collected 5,790 Sarcophagidae (55 species). Community parameters of Sarcophagidae were evaluated and compared. The ecological effects of anthropization and habitat type were observed in the present study. As expected, our results showed the highest abundance, species richness, and diversity in the savanna and forest habitats (natural), whereas the lowest values were registered in the urban and alfalfa crop habitats, supporting the hypotheses of anthropization as the main driver of diversity loss. In addition, sarcophagid assemblages differed between all habitats and the overall dissimilarity was structured by spatial turnover. The main conclusion of this research is that flesh fly community structure is greatly affected by anthropization and habitat type, and this would be related to canopy cover and microclimate conditions of each environment.
Assuntos
Biodiversidade , Ecossistema , Sarcofagídeos/fisiologia , Animais , Argentina , Cidades , Fazendas , Florestas , Pradaria , MasculinoRESUMO
The third instar and pupa of Neocorvicoana reticulata (Kirby, 1819) (Coleoptera: Scarabaeidae: Cetoniinae: Gymnetini) from Argentina, are described and illustrated. This is the first description of immatures in this genus. A key to the known third-stage larvae of New World Gymnetini species is provided, which now includes 19 species in 10 genera.