The Bostrychietum community of pneumatophores in Araçá Bay: an analysis of the diversity of macrofauna

Abstract

A mangrove forest can harbour several macroalgal assemblages growing on pneumatophores, roots, stems and other hard substrates. These algae belong to various genera, most typically Bostrychia, and form a community called the Bostrychietum. This study describes the fauna associated with the Bostrychietum and the effect of emersion time on the community. Seasonal samples were collected from pneumatophores on an island in Araçá Bay in 2012, in two areas, one on the border of the island and one inland. Each pneumatophore was considered a sample. The border samples, with a shorter emersion time, contained a richer algal flora associated with pneumatophores, and fauna with species of varied dietary habits. The inland samples, with a longer emersion time, contained only two algal genera and fauna species comprised mostly of omnivorous amphipods and desiccation-resistant detritivorous species. Macrofauna diversity and richness varied over time and were lower in spring. Therefore, the emersion time of the Bostrychietum and the period of the year affect the community structure, for both the macroalgae and the associated fauna.

Co-occurring morphologically distinct algae support a diverse associated fauna in the intertidal zone of Araçá Bay, Brazil

“…Mites (Acari), for example, use Bostrychietum as habitat and source of food and their spatial distribution on rocky shores is closely related to the host position (Pfingstl 2013). As previously observed for Bostrychietum covering mangrove pneumatophores in the same area (García et al 2016), the rocky shore Bostrychietum in our study showed the presence of more resistant organisms like bivalves, acaris, and typically terrestrial animals, such as insects. The occurrence of these organisms in the lower limit of Bostrychietum bed in the midlittoral zone may reflect a close algal-fauna association and, in turn, a side-effect of insects using the algae as a proxy of the height in the shore.…”

“…(Montagne 1842) and that normally occurs on the upper portions of the intertidal zone (García et al 2016); algal turf -dominated by the red filamentous algae Gracilaria sp. (Greville 1830) that mostly occurs in the intertidal fringe.…”

The highly diverse gastropod assemblages associated with Sargassum spp. (Phaeophyceae: Fucales) habitats

“…Even though gastropod densities presented some variation throughout the four sampling sites, the dominance of B. varium in all sites of Flamengo Bay was remarkable. Although this species often occurs in association with macrophytes, such high dominance levels are unusual, both in studies with other macrophyte species (Leite et al ., 2009; Creed & Kinupp, 2011; Barros & Rocha-Barreira, 2013; Zamprogno et al ., 2013; Queiroz & Dias, 2014; Duarte et al ., 2015; García et al ., 2015) and in studies with Sargassum sp. beds elsewhere on the Brazilian coast (Almeida, 2007; Jacobucci et al ., 2006; Longo et al ., 2014).…”

Effects of ocean warming, eutrophication and salinity variations on the growth of habitat-forming macroalgae in estuarine environments

“…These macroalgae, along with microalgae, represent a major source of primary productivity in mangrove ecosystems (Karsten et al 1994a), as they produce organic matter and participate in nutrient cycling (McClusky & Elliot 2004). Furthermore, they act as microhabitats for several organisms, mainly protists and invertebrates (García et al 2016;Borburema 2017;Vieira et al 2018) and can be indicators of environmental quality (Melville & Pulkownik 2006;Fontes et al 2007;Melville & Pulkownik 2007) and food resource for consumers (Campos et al 2015).…”