Publications

Lozanovska, I. (2020). Functional diversity as indicator of ecosystem functioning in Mediterranean riparian forests. Ph.D. thesis, Instituto Superior de Agronomia, Universidade de Lisboa, Portugal   Abstract: Riparian forests are ecosystems of high biodiversity and complexity driven by diverse environmental factors and increasingly threaten by anthropogenic pressures. Understanding and predicting vegetation responses to these factors have become one of the most challenging tasks in riparian ecology. This thesis aims to analyze the functional diversity responses of the Mediterranean riparian forests affected by multiple stressors to give insights into ecosystem functioning. The specific objectives were: (i) to assess the worldwide application of functional trait-based approaches in riparian forests; (ii) to determine the key habitat and regional environmental factors that influence the functional diversity of different forests; (iii) to assess the functional diversity patterns of aquatic plants and riparian woody vegetation to streamflow regulation. The results showed that the functional diversity concept has a long history of evolution. Its application to riparian forests has been increasing in the last two decades, with guild approaches becoming more popular than functional diversity indices. Functional richness is the most applied index in riparian plant studies. Amongst the environmental key-factors, precipitation plays a determinant role on the functional diversity of Mediterranean riparian forests, though especially pronounced for Mediterranean shrublands due to their low functional redundancy. Streamflow regulation can foster diverse stress-related functional strategies in contrasting biomes (boreal and Mediterranean), resulting in diverse functional diversity patterns. This result is likely related to a long legacy of adaptations to natural hydrological stress and to the magnitude of streamflow regulation. Further, diverse types of streamflow regulation (run-of-river dams and storage reservoirs) impair differently the cover and functional diversity of bryophytes, vascular macrophytes and riparian woody vegetation. The observed patterns of functional diversity can inform on the conservation status of the Mediterranean riparian forests and allow anticipating the vulnerability of the riparian ecosystems to future changes, which can guide mitigation, conservation or restoration plans.

Rivaes, R., Couto, J.S., Schmidt, L., Delicado, A., Aguiar, F.C. (2022). The influence of river regulation on the affinity for nature and perceptions of local populations. Journal of Environmental Management 321: 115992. DOI: 10.1016/j.jenvman.2022.115992 Abstract: Rivers are powerful systems supporting human civilization, but despite the enormous dependence on rivers by humans, this does not stop them to assault rivers in the most varied ways. Such dependency determines the establishment of strong river flow-human relationships, and river degradation the prompting of health and non-tangible complications for humans. This work assesses how river regulation, interacting with sociodemographic characteristics, influences the affinity for nature and the perception of humans regarding its effects on river systems. Increased affinity for nature and clearer perceptions about the effects of river regulation improve emotive connection with nature and promote pro-environmental concerns towards a more sustainable water management. Two case studies were selected with different river regulation types (run-of-river and storage reservoir). In each one, the affinity for nature and social perceptions were assessed via telephone-assisted questionnaire surveys carried out in 2020 using 402 randomly selected numbers of local human communities living in its influence areas. Results showed that despite river regulation, communities remain connected to the river system with well-established flow-human relationships. Nonetheless, these relationships have changed due to socioeconomic and cultural changes over time. Significant differences were found in educational attainment and age regarding the affinity for nature. On the other hand, gender differs significantly regarding both the affinity for nature and how the river regulation affect perception, highlighting a gender gap motivated by social and cultural customs passed throughout generations. The lower education level of women and less frequent use of the river acts as a barrier to their perception of river ecosystems and the regulation effects. The affinity for nature and the perception of ecosystems changes by local populations were also significantly different according to the river regulation type, where residents near the run-of-river dam present less affinity for nature. Notwithstanding, the perceptions of local communities were in general in accordance with the scientific knowledge on rivers’ condition. Finally, this work highlights the necessity for education through schools, local communities, municipalities and families, providing conditions for dedication and time to nature and promoting environmental knowledge through direct experience.

Rivaes, R. P., Feio, M. J., Almeida, S. F. P., Calapez, A. R., Sales, M., Gebler, D., Lozanovska, I., Aguiar, F. C. (2021). River ecosystem endangerment from climate change-driven regulated flow regimes. Science of The Total Environment, 151857. DOI:10.1016/j.scitotenv.2021.151857 Abstract: Major threats of freshwater systems are river damming and habitat degradation, further amplified by climate change, another major driver of biodiversity loss. This study aims to understand the effects of climate change, and its repercussions on hydropower production, on the instream biota of a regulated river. Particularly, it aims to ascertain how mesohabitat availability downstream of hydropower plants changes due to modified flow regimes driven by climate change; how mesohabitat changes will influence the instream biota; and if instream biota changes will be similar within and between biological groups. We used a mesohabitat-level ecohydraulic approach with four biological elements – macrophytes, macroalgae, diatoms and macroinvertebrates – to encompass a holistic ecosystem perspective of the river system. The ecological preferences of the biological groups for specific mesohabitats were established by field survey. The mesohabitat availability in three expected climate change-driven flow regime scenarios was determined by hydrodynamic modeling. The biota abundance/cover was computed for the mesohabitat indicator species of each biological group. Results show that climate-changed flow regimes are characterized by a significant water shortage during summer months already for 2050. Accordingly, the regulated rivers' hydraulics are expected to change towards more homogeneous flow conditions where run habitats should prevail. As a result, the biological elements are expected to face abundance/cover modifications ranging from decreases of 76% up to 67% increase, depending on the biological element and indicator taxa. Diatoms seem to endure the greatest range of modifications while macrophytes the slightest (15% decrease to 38% increase). The greatest modifications would occur on decreasing abundance/cover responses. Such underlies an important risk to fluvial biodiversity in the future, indicting climate change as a significant threat to the fluvial system in regulated rivers.

Calapez, A. R., Serra, S. R. Q., Rivaes R., Aguiar, F. C., Feio, M. J. (2021). Influence of river regulation and instream habitat on invertebrate assemblage’ structure and function. Science of the Total Environment 794: 148696. DOI: 10.1016/j.scitotenv.2021.148696 Abstract: Dams modify geomorphology, water quantity, quality and timing of stream flows affecting ecosystem functioning and aquatic biota. In this study, we addressed the structural and functional macroinvertebrate community alterations in different instream mesohabitats of two Portuguese rivers impaired by dams. We sampled macroinvertebrates in riffles, runs and pools of river sites downstream of the dams (i.e. regulated; n = 24) and in sites without the influence of the dams (i.e. unregulated; n = 7), assessing a total of 64 mesohabitats, following late spring-early summer regular flows. We found a distinct taxonomic structure and trait composition of macroinvertebrate assemblages between regulated and unregulated flow sites, and also between mesohabitats in which the differences were more evident. When analysing each mesohabitat individually, the effect of flow regulation was detected only in run-type mesohabitats for both taxonomic and trait composition, leading us to infer that a selective macroinvertebrate assessment on run mesohabitats would be a valuable contribution to detect regulated flow effects on ecosystems impaired by dams. Additionally, there is evidence that respiration and locomotion traits could be effective tools to identify damming flow alterations. This study supports that the quality assessments of rivers impacted by dams could benefit from a sampling approach focused on run mesohabitats and the detection of some key traits, which would improve assessment accuracy.

Rivaes, R. P., Feio, M. J., Almeida, S. F. P., Vieira, C., Calapez, A. R., Mortágua, A., Gebler, D., Lozanovska, I., Aguiar, F. C. (2020). Multi-biologic group analysis for an ecosystem response to longitudinal river regulation gradients. Science of The Total Environment, 767. DOI: 10.1016/j.scitotenv.2020.144327   Abstract: This work assesses the effects of river regulation on the diversity of different instream and riparian biological communities along a relieve gradient of disturbance in regulated rivers. Two case studies in Portugal were used, with different river regulation typology (downstream of run-of-river and reservoir dams), where regulated and free-flowing river stretches were surveyed for riparian vegetation, macrophytes, bryophytes, macroalgae, diatoms and macroinvertebrates. The assessment of the regulation effects on biological communities was approached by both biological and functional diversity analysis. Results of this investigation endorse river regulation as a major factor differentiating fluvial biological communities through an artificial environmental filtering that governs species assemblages by accentuating species traits related to river regulation tolerance. Communities' response to regulation gradient seem to be similar and insensitive to river regulation typology. Biological communities respond to this regulation gradient with different sensibilities and rates of response, with riparian vegetation and macroinvertebrates being the most responsive to river regulation and its gradient. Richness appears to be the best indicator for general fluvial ecological quality facing river regulation. Nevertheless, there are high correlations between the biological and functional diversity indices of different biological groups, which denotes biological connections indicative of a cascade of effects leading to an indirect influence of river regulation even on non-responsive facets of communities' biological and functional diversities. These results highlight the necessary holistic perspective of the fluvial system when assessing the effects of river regulation and the proposal of restoration measures.