Browsing by Author "Sousa, Ronaldo"
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- Assessing the morphological variability of unio delphinus spengler, 1783 (Bivalvia: Unionidae) using geometric morphometryPublication . Morais, Pedro; Rufino, Marta M.; Reis, Joaquim; Dias, Ester; Sousa, RonaldoThe morphological variability of freshwater bivalve species, observed between and within river basins, may hamper their correct identification, even by experienced researchers. Classic morphometric measurements, i.e. shell length, height and thickness, or their ratios, are generally insufficient to distinguish populations and/or species. These issues may be overcome using a geometric morphometric method, which allows analysis of the overall shape of the individual, independently of its size. Thus, we aimed to test the usefulness of two geometric morphometric tools, landmarks and sliding semilandmarks, to evaluate the morphological variability of Unio delphinus Spengler, 1783 in three habitats of the Guadiana Basin (SW Iberian Peninsula, Europe): estuary, river and stream. We used 13 landmarks located on the shell interior (at the teeth, muscle scars and pallial line) and 35 sliding semilandmarks for the shell contour. These morphometric analyses showed that the shell shape of U. delphinus differs significantly among different habitats. Estuarine and stream shells are the most disparate (James index = 649.114, permutation P-value <0.001) and variability is not related to variations in shell size. The main differences in shell morphology are the following: (1) estuarine shells are more elongate, while riverine shells are more subovate; (2) the anterior curvature at the umbo is steeper in estuarine and riverine shells; (3) estuarine shells have an arched curvature at the ventral part of the shell, which is absent in specimens from the other habitats. Our data suggest that the morphology of U. delphinus shells might be influenced by the water flow characteristics of each habitat, since shells exhibited characteristics that are typically observed in freshwater mussels from lotic and lentic habitats.
- A global meta‐analysis of ecological functions and regulating ecosystem services of freshwater bivalvesPublication . Zieritz, Alexandra; Brian, Joshua I.; Sousa, Ronaldo; Aldridge, David C.; Atkinson, Carla L.; Douda, Karel; Vaughn, Caryn; Bespalaya, Yulia; Richmond, Tabitha; Ćmiel, Adam M.; Crisp, Alma; Dobler, Andreas H.; Ercoli, Fabio; Esteves, Eduardo; Ferreira‐Rodríquez, Noé; Geist, Juergen; González, Irene Sánchez; Halabowski, Dariusz; Hoos, Philipp; Hopper, Garrett W.; Hyvärinen, Heini; Ilarri, Martina; Lewin, Iga; Lipińska, Anna M.; Mageroy, Jon H.; Nizzoli, Daniele; Ollard, Isobel; Österling, Martin; Riccardi, Nicoletta; Rock, Sebastian L.; Sjönberg, Tuomo; Taskinen, Jouni; Urbanič, Gorazd; Urbańska, Maria; Yu, Qingqing; Vaz, Ana SofiaFreshwater bivalves are globally distributed, diverse, and common in benthic communities. Many taxa, par-ticularly in the most species-rich order, Unionida, are declining due to anthropogenic stressors, while a small number of non-native species have become increasingly abundant and widespread, commonly replacing nativebivalve assemblages. To understand how these global changes may impact ecosystems and people, we con-ducted a meta-analysis of existing literature quantifying the ecological functions (= supporting or intermediateecosystem services) and regulating ecosystem services of freshwater bivalves (hereafter “ecosystem services”).Random effects meta-analysis modeling across 447 case studies revealed a positive effect on human health,safety, or comfort of freshwater bivalve ecosystem services overall and specifically, via effects on nativemacrofauna, microorganisms, wastes, and pollutants, and the physico-chemical condition or quantity of sedi-ments. Generally, effects of native species and species within the orders Unionida and Venerida were more sig-nificant and positive than those of other freshwater bivalves. No significant overall effect was found forecosystem services related to zooplankton, algae, invasive species, and the physico-chemical condition of ambi-ent water. Moreover, a significant bias toward publication of positive results existed for studies quantifying eco-system services related to algae. These findings illustrate the global importance of the ecosystem services offreshwater bivalves and highlight the need for large-scale conservation and restoration efforts for their speciesand populations globally, including those of common species. Our findings also question common assumptionsof strong and ubiquitous effects of freshwater bivalves on algae and water condition, cautioning against extrapo-lating observations across systems.
- A global synthesis of ecosystem services provided and disrupted by freshwater bivalve molluscsPublication . Zieritz, Alexandra; Sousa, Ronaldo; Aldridge, David C.; Douda, Karel; Esteves, Eduardo; Ferreira-Rodriguez, Noe; Mageroy, Jon H.; Nizzoli, Daniele; Osterling, Martin; Reis, Joaquim; Riccardi, Nicoletta; Daill, Daniel; Gumpinger, Clemens; Vaz, Ana SofiaIdentification of ecosystem services, i.e. the contributions that ecosystems make to human well-being, has proven instrumental in galvanising public and political support for safeguarding biodiversity and its benefits to people. Here we synthesise the global evidence on ecosystem services provided and disrupted by freshwater bivalves, a heterogenous group of >1200 species, including some of the most threatened (in Unionida) and invasive (e.g. Dreissena polymorpha) taxa globally. Our systematic literature review resulted in a data set of 904 records from 69 countries relating to 24 classes of provisioning (N = 189), cultural (N = 491) and regulating (N = 224) services following the Common International Classification of Ecosystem Services (CICES). Prominent ecosystem services included (i) the provisioning of food, materials and medicinal products, (ii) knowledge acquisition (e.g. on water quality, past environments and historical societies), ornamental and other cultural contributions, and (iii) the filtration, sequestration, storage and/or transformation of biological and physico-chemical water properties. About 9% of records provided evidence for the disruption rather than provision of ecosystem services. Synergies and trade-offs of ecosystem services were observed. For instance, water filtration by freshwater bivalves can be beneficial for the cultural service ‘biomonitoring’, while negatively or positively affecting food consumption or human recreation. Our evidence base spanned a total of 91 genera and 191 species, dominated by Unionida (55% of records, 76% of species), Veneroida (21 and 9%, respectively; mainly Corbicula spp.) and Myoida (20 and 4%, respectively; mainly Dreissena spp.). About one third of records, predominantly from Europe and the Americas, related to species that were non-native to the country of study. The majority of records originated from Asia (35%), with available evidence for 23 CICES classes, as well as Europe (29%) and North America (23%), where research was largely focused on ‘biomonitoring’. Whilst the earliest record (from 1949) originated from North America, since 2000, annual output of records has increased rapidly in Asia and Europe. Future research should focus on filling gaps in knowledge in lesser-studied regions, including Africa and South America, and should look to provide a quantitative valuation of the socio-economic costs and benefits of ecosystem services shaped by freshwater bivalves.