Browsing by Author "Rebelo, Rui"
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- Can heat waves change the trophic role of the world's most invasive crayfish ? Diet shifts in Procambarus clarkiiPublication . Carreira, Bruno M.; Segurado, Pedro; Laurila, Anssi; Rebelo, RuiIn the Mediterranean basin, the globally increasing temperatures are expected to be accompanied by longer heat waves. Commonly assumed to benefit cold-limited invasive alien species, these climatic changes may also change their feeding preferences, especially in the case of omnivorous ectotherms. We investigated heat wave effects on diet choice, growth and energy reserves in the invasive red swamp crayfish, Procambarus clarkii. In laboratory experiments, we fed juvenile and adult crayfish on animal, plant or mixed diets and exposed them to a short or a long heat wave. We then measured crayfish survival, growth, body reserves and Fulton's condition index. Diet choices of the crayfish maintained on the mixed diet were estimated using stable isotopes (13C and 15N). The results suggest a decreased efficiency of carnivorous diets at higher temperatures, as juveniles fed on the animal diet were unable to maintain high growth rates in the long heat wave; and a decreased efficiency of herbivorous diets at lower temperatures, as juveniles in the cold accumulated less body reserves when fed on the plant diet. Heat wave treatments increased the assimilation of plant material, especially in juveniles, allowing them to sustain high growth rates in the long heat wave. Contrary to our expectations, crayfish performance decreased in the long heat wave, suggesting that Mediterranean summer heat waves may have negative effects on P. clarkii and that they are unlikely to boost its populations in this region. Although uncertain, it is possible that the greater assimilation of the plant diet resulted from changes in crayfish feeding preferences, raising the hypotheses that i) heat waves may change the predominant impacts of this keystone species and ii) that by altering species' trophic niches, climate change may alter the main impacts of invasive alien species
- Distribution of alien tetrapods in the Iberian PeninsulaPublication . Ascensão, Fernando; D'Amico, Marcello; Martins, Ricardo C.; Rebelo, Rui; Barbosa, A. Márcia; Bencatel, Joana; Barrientos, Rafael; Abellán, Pedro; Tella, José L.; Cardador, Laura; Anadón, José D.; Carrete, Martina; Murgui, Enrique; Fernandes, Pedro; Santos, Sara M.; Mira, António; da Luz Mathias, Maria; Tiago, Patrícia; Casabella, Eduardo; Reino, Luís; Paulo, Octávio S.; Pereira, Henrique M.; Capinha, CésarWe present a dataset that assembles occurrence records of alien tetrapods (amphibians, reptiles, birds and mammals) in the Iberian Peninsula, a coherent biogeographically unit where introductions of alien species have occurred for millennia. These data have important potential applications for ecological research and management, including the assessment of invasion risks, formulation of preventive and management plans, and research at the biological community level on alien species. This dataset summarizes inventories and data sources on the taxonomy and distribution of alien tetrapods in the Iberia Peninsula, comprising known locations from published literature, expert knowledge and citizen science platforms. An expertbased assessment process allowed the identification of unreliable records (misclassification or natural dispersion from native range), and the classification of species according to their status of reproduction in the wild. Distributional data was harmonized into a common area unit, the 10 × 10 km Universal Transverse Mercator (UTM) system (n = 6,152 cells). The year of observation and/or year of publication were also assigned to the records. In total, we assembled 35,940 unique distribution records (UTM × species × Year) for 253 species (6 amphibians, 16 reptiles, 218 birds and 13 mammals), spanning between 1912 and 2020. The species with highest number of distribution records were the Mediterranean painted frog Discoglossus pictus (n = 59 UTM), the pond slider Trachemys scripta (n = 471), the common waxbill Estrilda astrild (n = 1,275) and the house mouse Mus musculus (n = 4,043), for amphibians, reptiles, birds and mammals, respectively. Most alien species recorded are native to Africa (33%), followed by South America (21%), Asia (19%), North America (12%) and Oceania (10%). Thirty-six species are classified by IUCN as threatened in their native range, namely 2 Critically Endangered (CR), 6 Endangered (EN), 8 Vulnerable (VU), and 20 species Near Threatened (NT). Species maps are provided in DataSet1, as well R code and GIS layers to update them as new records are obtained.
- Reproduction of the blue jack mackerel, Trachurus picturatus, in western Portugal: microscopic gonad analysis reveals indeterminate fecundity and skipped spawning patternsPublication . Neves A.; Sequeira V.; Vieira A.R.; Silva E.; Silva F., Duarte A.M.; Mendes S.; Ganhão R.; Assis C.; Rebelo, Rui; Magalhães M.F.; Gil M.M.; Gordo L.S.Blue jack mackerel, Trachurus picturatus, is the fifth most landed fish species in mainland Portugal, but information on its reproductive biology is scarce. From September 2018 to August 2019, 626 specimens were collected from commercial vessels to clarify the reproductive strategy of the T. picturatus population off the west coast of Portugal. The proportion and length range of males and females were similar. Only three of the specimens collected were categorized as immature, indicating that the fish caught in the fishery are primarily mature. The spawning season lasted from late January until the end of March, with gonadosomatic indices being similar for males and females. Fecundity was indeterminate, and estimated batch fecundity ranged between 6,798 (at 25.4 cm TL) and 302,358 oocytes (at 33.8 cm TL). The low number of females showing direct evidence of imminent or recent spawning suggests a low number of spawning events. In addition, 12.7% of females were considered non-reproductive due to ovary abnormalities including parasitic infection by Kudoa species, atretic structures and skipped spawning events. This study highlights the importance of accounting for skipped spawning events and ovary abnormalities in the management of species fisheries.
- Spatial distribution of inter-nesting green turtles from the largest Eastern Atlantic rookery and overlap with a marine protected areaPublication . Raposo, C; Mestre, J; Rebelo, Rui; Regalla, A; Davies, A; Barbosa, C; Patrício, ARUnderstanding the spatial distribution of wildlife is fundamental to establish effective conservation measures. Tracking has been key to assess movement patterns and connectivity of sea turtles, yet some regions of great significance are largely understudied. We tracked 44 green turtles from the largest rookery in the Eastern Atlantic, on Poilão Island, Guinea-Bissau, during 2018 through 2020, to assess their inter-nesting movements, connectivity with nearby islands and fidelity to inter-nesting sites. Additionally, we investigated individual and environmental factors that may guide inter-nesting distribution and assessed the adequacy of a marine protected area to support this population during the breeding period. Green turtles had an overall home range of 124.45 km2, mostly occupying a restricted area around Poilão Island, with 52% of this home range falling within the no-take zone of the João Vieira-Poilão Marine National Park. Turtles exhibited strong fidelity to inter-nesting sites, likely as a strategy to save energy. Only 2 turtles performed significant excursions out of the park, and connectivity between Poilão and nearby islands within the park was limited. Larger turtles and turtles tagged later in the nesting season tended to have smaller core areas and home ranges; thus, experienced breeders may be moving less and potentially benefit from energy saving. This study highlights the importance of a marine protected area for the conservation of one of the largest green turtle breeding populations globally, and provides suggestions for further increasing its effectiveness.
- The relevance of Evolutionary Significant Units for the conservation of island-restricted reptiles: Tarentola boettgeri bischoffi as a case studyPublication . Rato, Catarina; Oliveira, Paulo; Menezes, Dília; Funk, Stephan M.; Rebelo, Rui; Nogales, Manuel; Rocha, RicardoWithin vertebrates, reptiles are good island colonisers, often leading to considerable levels of intraspecific diversity among populations inhabiting different islands/archipelagos. This study explores the mitochondrial phylogeographic structure of Tarentola boettgeri, a gecko species endemic to the Macaronesian archipelagos of Selvagens and the Canary Islands. Our research introduces a novel monophyletic group, comprising the populations from the islands of Selvagem Pequena and Ilhéu de Fora. Furthermore, we confirm the previously identified genetic clusters associated with Selvagem Grande, Gran Canaria and El Hierro. We estimate that the origin of T. boettgeri dates to the upper Miocene (ca. 6.4 Mya), and that the separation of T. boettgeri bischoffi on Selvagem Grande, Selvagem Pequena, and Ilhéu de Fora, occurred ca. 0.5 Mya. The absence of genetic differences between Selvagem Pequena and Ilhéu de Fora suggests recent gene flow or founder events, possibly facilitated by land connections during major glaciations. Conversely, the geographic barriers between Selvagem Grande and Selvagem Pequena likely persisted, preventing genetic admixing. The significant genetic distances observed among all populations underscore the necessity of an integrative taxonomic revision for T. boettgeri. In light of our findings, and with particular consideration of the small population sizes of T. boettgeri bischoffi on Selvagem Pequena and Ilhéu de Fora, we propose that the identified monophyletic groups should be managed as Evolutionarily Significant Units (ESUs). Accordingly, our study highlights the importance of recognizing ESUs in island-restricted reptile populations for targeted conservation efforts, especially given their unique intraspecific diversity and the vulnerability of their habitats.
- Using and Creating Microclimates for Cork Oak Adaptation to Climate ChangePublication . Vizinho, André; Príncipe, Adriana; Vasconcelos, Ana Cátia; Rebelo, Rui; Branquinho, Cristina; Penha-Lopes, GilIn Mediterranean climate regions, climate change is increasing aridity and contributing to the mortality rate of Quercus suber, reducing the success of reforestation efforts. Using and creating microclimates is a recommended climate adaptation strategy that needs research. Our hypothesis is that planting Q. suber in north-facing slopes and water lines results in a higher survival rate than those that are planted in ridges and south-facing slopes. Secondly, our hypothesis is that existing shrubs (in this case, Cistus ladanifer) can be used to create microclimatic sheltering and increase the survival of Q. suber plantations. In experiment 1, we tested the survival of Q. suber plantations in four different topographic conditions. For that, 80 Q. suber plants were planted over four different topographic conditions, where soil probes were installed to monitor soil moisture and temperature. Two years after, the results show an increased survival rate in the north-facing slope and water line when compared to the ridge area (p = 0.032). In experiment 2, we tested if planting in the shade of rows of C. ladanifer increases the survival rate of Q. suber plantations. For that, 1200 Q. suber plants were planted; 600 in a Montado open area with no shade and 600 under the shade of rows of C. ladanifer shrubs. A total of 17 months after plantation, there was a significantly higher survival rate of the shaded plants (p = 0.027). We conclude that microclimates created by topography and shrubs can have a significant impact on the survival of Q. suber plantations and discuss the situations in which these can apply.