Author(s):
Santos, Joana Isabel ; Silva, Carlos ; Gonçalves, Fernando J. M. ; Pereira, Joana Luísa ; Castro, Bruno B.
Date: 2024
Persistent ID: https://hdl.handle.net/1822/91126
Origin: RepositóriUM - Universidade do Minho
Project/scholarship:
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDP%2F50017%2F2020/PT;
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDB%2F50017%2F2020/PT;
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UID%2FBIA%2F04050%2F2019/PT;
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDB%2F04050%2F2020/PT;
info:eu-repo/grantAgreement/FCT/FARH/SFRH%2FBD%2F121341%2F2016/PT;
info:eu-repo/grantAgreement/FCT/POR_CENTRO/SFRH%2FBD%2F138389%2F2018/PT;
Subject(s): Drought; Ecological status; Environmental gradient; Macroinvertebrate communities; Mediterranean streams; Water availability
Description
Published: 29 December 2023
Climate change has been increasing the frequency and severity of drought periods. There is a need to understand how this water scarcity affects aquatic communities. The main aim of this work was to compare the macroinvertebrate communities and their bioindicator value (ecological status sensu the Water Framework Directive) in three Regions [northeast (N), central (C) and south (S)] of Portugal along a water availability and climate gradient, in two consecutive years that reflect hydrologically distinct scenarios (2018 versus 2019). The period prior to sampling (summer and autumn 2017) was extremely dry and hot, whereas climatic fluctuations in 2018–2019 (when the sampling occurred) were closer to the norm. A total of 28 sampling sites were surveyed in streams of Regions where water scarcity is differentially constitutive. The results showed a consistent environmental and ecological gradient in both years, despite the background differences. A coinciding mineralization, temperature, riparian cover and water availability gradient clearly separated Regions C (wettest) and S (driest), with Region N occupying an intermediate position. Region C had overall higher ecological quality (prevalence of sensitive organisms) in both years. Despite our a priori expectations that 2018 would represent a much more stressful condition, with larger differences across Regions (because of their constitutive background), the data suggest that macroinvertebrate communities may be resilient or adapted, to some degree, to hydrological fluctuations. Signs of more favourable conditions in 2019 were also observed (general improvement in ecological status). Studies across hydrological and climatic gradients (in time and space) are particularly important where water availability is becoming more challenging.
This work was supported by national funds (through Fundação para a Ciência e Tecnologia, Portugal) by means of the institutional programmes UIDP/50017/2020, UIDB/50017/2020 and LA/P/0094/2020 (CESAM), as well as UID/BIA/04050/2019 and UIDB/04050/2020 (CBMA, https://doi.org/10.54499/UIDB/04050/2020). Joana Isabel Santos and Carlos Silva were supported by individual doctoral grants (SFRH/BD/121341/2016 and SFRH/ BD/138389/2018) by FCT. Funding institutions played no role in study design, data collection and interpretation, nor in manuscript preparation and submission. The authors acknowledge the assistance of Sandra Nogueira, who produced Fig. 1 using GIS software (location of sites and regions).
