Diversity of Odonata (Insecta) in Seasonal Deciduous Forest fragments in southern Brazil (state of Rio Grande do Sul), with a new record for the state and comments on the seasonal distribution of the species

Abstract

We present an Odonata (Insecta) check list of species occurring in a fragment of the Seasonal Deciduous Forest (Atlantic Forest biome) from the central region of the state of Rio Grande do Sul (RS), southern Brazil, along with a list of the odonate species recorded in this phytoecological region for the state. In addition, we provide comments on the seasonal distribution of the species occurring in the study area. Two streams and seven farm ponds located in the middle course of the Jacuí River basin were surveyed between December 2007 and February 2009. Overall, we recorded 49 species from 21 genera and six families. Argia serva Hagen in Selys, 1865 (Coenagrionidade) had its first occurrence record mentioned for the state, elevating to 183 the total number of Odonata species occurring in Rio Grande do Sul. The number of species recorded in the study area corresponds to ~26% of the known Odonata diversity in RS. Libellulidae was the most species-rich family (22 species, ~45% of the total), followed by Coenagrionidae (18 species, 37% of the total). The checklist for the Seasonal Deciduous Forest in RS indicated the occurrence of 83 species of Odonata in this phytoecological region (~45% of the known odonate species in the state). This elevated diversity could be related to the density of the vegetation structure. In the study area, 20 species were found in streams, and 45 in farm ponds. Species occurrence showed marked seasonal patterns in the study area, with 88% of the species recorded from summer to autumn, and no species detected in streams in the winter. Moreover, 70% of the species were recorded in either one or two seasons in farm ponds, while 65% occurred solely in one season in streams. This result indicates that the life cycle of Odonata in southern Brazil is strongly influenced by seasonal patterns in temperature.

Environmental drivers and composition of assemblages of immature odonates (Insecta) in a subtropical island in southern Brazil

“…Most odonate taxa were associated with warmer periods of the year, while few taxa (Calopterygidae) occurred in winter periods. This result agrees with previous studies describing seasonal patterns in the assemblage structure of odonates in subtropical Brazil (Pires et al, 2014(Pires et al, , 2019 and reinforces the importance of climate in structuring the occurrence of Odonata in stream ecosystems. Temperature is a strong driver of the life cycle of aquatic insects (Corbet et al, 2006), and is particularly important for odonates because it has an important role in larval development (Corbet, Acta Limnologica Brasiliensia, 2020, vol.…”

“…32, e2 2004). Although very few studies have assessed the life cycles of immature Odonata in subtropical regions of Brazil, a recent study showed that the occurrence of species of Odonata inhabiting streams in southernmost Brazil was highly constrained in colder periods of the year, (Pires et al, 2019), thus explaining the positive association with the occurrence of most genera. Calopterygidae was the solely taxa that occurred in winter.…”

Dragonflies (Insecta: Odonata) from Mananciais da Serra, a Tropical-Araucaria Forest ecotonal remnant in the southern Atlantic Forest, state of Paraná, Brazil

“…All families were more abundant in TF except Libellulidae. Despite being the richest family, its representatives occurred at a low frequency in TF, possibly due to the low availability of the characteristically lentic system and its preference; similar results were found by Pires et al (2019).…”

“…Efforts to understand the diversity of odonates in southern Brazil have dramatically increased in the last decade, at least for Pampean and Atlantic Forest formations in the state of Rio Grande do Sul (e.g. Renner et al 2016, 2017, Dalzochio et al 2018, Pires et al 2019. However, knowledge about Odonata of Paraná is still meager.…”

Influence of different riparian vegetation widths and substrate types on the communities of larval Odonata (Insecta) in southern Brazilian streams

“…Because of the seasonal sampling design of the study (winter and summer samplings) and prior evidence of seasonal dynamics in odonate communities in southern Brazil (Pires et al, 2014(Pires et al, , 2019(Pires et al, , 2020, we first assessed whether Odonata community composition changed between seasons before proceeding to the main analyses. For this purpose, we carried out a non-parametric multivariate analysis of variance (PERMANOVA; 9999 permutations) with the raw dataset (N = 72; three tributaries x four reaches x three substrate x two seasons).…”