Spatial scale drives diversity patterns of benthic macroinvertebrate communities in tropical estuaries

Abstract

Identifying the hierarchical spatial levels that show the greatest dissimilarities between communities and how these patterns are generated is essential to provide insights into the monitoring and protection of biodiversity. In this study, we additively partitioned diversity of macroinvertebrates into alpha, beta, and gamma diversity across multiple scales in typical and semi‐arid tropical estuaries. We also determined which components of the total beta diversity, in terms of species replacement or richness difference (presence‐absence data) and abundance difference (relative abundance data), had the greatest relative importance in structuring the composition of benthic macrofauna. In typical and semi‐arid tropical estuaries, a non‐random spatial pattern was observed in additive partitioning of diversity, with higher values of beta diversity obtained at the largest scales analyzed. When considering the presence‐absence data, in general there was no clear trend which components of beta diversity had greater relative importance in typical estuaries. In the semi‐arid tropical estuaries, the richness difference component showed greater relative importance in the rainy season, whereas the species replacement presented greater proportions in the dry season. When considering abundance data, in general the abundance difference component showed greater relative importance in typical and semi‐arid tropical estuaries in the two seasonal periods. Therefore, approaches based on the presence/absence and on the relative abundance of species provided complementary answers about the distribution patterns of benthic macroinvertebrate communities. We demonstrated that environmental filtering and dispersal limitation may affect the patterns of distribution of benthic macrofauna in estuaries located in regions with different climatic conditions.

Taxonomic richness and its relationship to the functional diversity of polychaetes in tropical estuaries

“…The main input of freshwater to these estuaries is from groundwater and low rainfall (Santiago et al, 2005), and due to climatic characteristics and tidal action, the salinity in these estuaries may exceed that of the sea, leading to the formation of inverse hypersaline estuaries (Dias et al, 2007;Medeiros, Costa, et al, 2016). However, during this study, salinity in the semiarid estuaries varied from 25 ppm (upper estuary) to 41 ppm (lower estuary), which does not classify them as hypersaline (Medeiros, Heino, et al, 2021). These estuaries are approximately 10 km long F I G U R E 1 Hypothesis proposed to demonstrate the relationship between taxonomic richness and functional components: functional richness, functional evenness and functional divergence in typical tropical estuaries (a) and semiarid tropical estuaries (b), and the trait dominance in typical tropical estuaries and semiarid tropical estuaries in north-eastern Brazil (c).…”

“…Therefore, most studies on polychaetes gather information from the genus level (Duarte et al, 2020;Medeiros, Heino, et al, 2021;Medeiros, Paiva, et al, 2021;Van der Linden et al, 2017). It is important to highlight that, depending on the objective of the study, coarser resolutions, that is, family and genus levels, can respond similarly to changes in the assemblage of polychaetes in tropical estuaries (Nóbrega- .…”

“…Bhowmik & Mandal, 2021; Bremner et al., 2003; D'Alessandro et al., 2020; Van der Linden et al., 2012, 2016; Zhong et al., 2020), although an increase in the number of studies carried out in estuaries in tropical regions has been observed in recent times (e.g. Duarte et al., 2020; Lam‐Gordillo et al., 2020; Medeiros, Heino, et al., 2021; Medeiros, Paiva, et al., 2021; Van der Linden et al., 2017; Wouters et al., 2018). In general, these studies aim to understand how environmental characteristics affect benthic community functions in estuaries.…”

Biological invasions alter consumer–stress relationships along an estuarine gradient

“…Temperature was the least variable at Mid (Appendix S1: Figure S1), so patterns of environmental stress might deviate from linear predictions in the ESM, resulting in higher diversity and effects of predators at this site than others. Additionally, seasonal variation could be more important in structuring these patterns than was initially expected (Medeiros et al, 2020). The estuarine salinity gradient in Tomales Bay is weakened during the summer when sessile invertebrates have their highest recruitment (Hearn & Largier, 1997; Stachowicz & Byrnes, 2006), and this pattern is typical among Mediterranean climates.…”

Effects of Spartina alterniflora invasion on the benthic invertebrate community in intertidal wetlands

“…Species turnover suggests that the observed community patterns may have resulted from environmental filtering (Sommer et al, 2014). As the environmental conditions of the intertidal wetlands change from the inland to the sea, the number and identity of species that inhabit each habitat zone vary due to environmental filtering owing to salinity, thereby generating a natural species turnover gradient (Medeiros et al, 2020). The mean salinity values of our study ranged from 8.35 to 31.89, revealing a gradient of low‐salt to high‐salt environments.…”