Structuring functional groups of aquatic insects along the resistance/resilience axis when facing water flow changes

Abstract

Understanding how differences in intensity and frequency of hydrological disturbances affect the resistance and resilience of aquatic organisms is key to manage aquatic systems in a fast‐changing world. Some aquatic insects have strategies that improve the permanence (resistance), while others use strategies that favor recolonization (resilience). Therefore, we carried out a manipulative experiment to understand the influence of functional characteristics of aquatic insects in their permanence and recolonization against hydrological disturbances in streams in the biodiversity hotspot of the Cerrado of Brazil. We placed 200 artificial substrates in five streams and submitted them to changing water flow regimes that differed both in frequency and intensity, and we observed the response of the aquatic community for 39 days. We used a hierarchical Bayesian approach to estimate the probabilities of permanence and recolonization of each life strategy group (nine groups). We observed that the most intense changes in the water flow tended to affect the permanence of almost all groups, but the intensity of this effect reduced over time. On the other hand, less frequent disturbances, regardless of intensity, tended to reduce the permanence of most groups of aquatic insects over time. The different effects of disturbance intensity may have been related to a greater recolonization capacity of some groups. The results we present are worrisome in a scenario of reduced riparian vegetation around streams and with the expectation of precipitation becoming more concentrated in shorter periods of time due to climate change in the Cerrado hotspot, reducing the occurrence of many groups of aquatic insects in their habitat, particularly those with traits associated with resistance against hydrological disturbance.

The drift effect on nestedness of ephemeroptera, trichoptera and plecoptera orders in the Xingu River

“…The EPT orders have a wide global distribution and there are many studies with this group about its ecology and bionomics characteristics (Marques et al 1999, Baumgartner et al 2004, Galdean et al 2001 Gualdoni & Oberto 2012, Godoy, Valente-Neto, et al 2022. We can better understand the dynamics of dispersion and drift when we observe the characteristics of each order separately.…”

“…The active dispersal movement occurs more intensely during the night period, where the lack of luminosity provides a protection against the predators, guaranteeing a greater success during the displacement in the water column (Bishop 1969, Koetsier 2005. There are many studies with the orders Ephemeroptera, Plecoptera and Trichoptera (EPT) about their distribution and life cycle (Godoy, Valente-Neto, et al 2022, Merritt et al 2008, Sarremejane et al 2020. In addition, they are orders with high environmental sensitivity, wide distribution within the lotic environments, high abundance and each order presents high richness and complexity (Godoy et al 2019), which allows its use as model organisms for studies of the drift process.…”

Local factors and bionomic characteristics determining the occurrence of semiaquatic bugs in streams of Central Amazonia

“…This result is interesting because it indicates that although R. evidis belongs to the same taxonomic group and phylogenetic clade as R. amazonensis , the responses of the species were different. Studies on functional and numerical responses in aquatic insects have shown such a pattern, in which the measurement of a single community response can mask individual species responses, be the species phylogenetically close (Godoy et al, 2018) or functionally similar (Godoy, Valente‐Neto, et al, 2022). Thus, even if the use of taxonomic groups (and different taxonomic resolutions) in applied studies (e.g., biomonitoring) presents satisfactory results for such objectives (da Giehl et al, 2014; Godoy et al, 2019), species distribution, and population and community dynamics studies should consider species idiosyncrasies to better understand co‐occurrence mechanisms (Guterres et al, 2020).…”

“…The study of diversity turnover among sites becomes incomplete when information regarding the idiosyncratic responses of the species is not considered (Godoy, Queiroz, et al, 2022; Godoy, Valente‐Neto, et al, 2022). Such information would explain how species respond to environmental conditions, enabling a better understanding of the mechanisms that cause shifts among communities (Opedal et al, 2020; Ovaskainen et al, 2017).…”

“…Despite this well‐known dependence between occurrence and environment type, few studies have been conducted to analyse habitat preference at the semiaquatic bugs (Hemiptera, Gerromorpha) species level, making it difficult to develop refined hypotheses for species' occurrence. More species‐oriented hypotheses enable a better understanding of the observed patterns, especially with respect to changes in biological communities (Godoy, Valente‐Neto, et al, 2022; Verberk et al, 2013). In addition, it also allows us to discern whether a trait being studied is the result of ecological processes or the product of phylogenetic inertia when comparing responses between near groups (Godoy et al, 2018; Webb et al, 2002; Westoby et al, 1995).…”