Search Results (19)

This study evaluated soil–atmosphere greenhouse gas (GHG) fluxes—including carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O)—in cacao agroecosystems on São Tomé Island, Central Africa. The field campaign was conducted between April and May 2025, coinciding with the transition from the short rainy season to the onset of the dry period. The sampling design comprised two system types (biodiverse and conventional), two crop development stages (growing and productive), and two climatic zones (wet and dry). Gas fluxes were measured using the static chamber method and analyzed in relation to climatic, topographic, and edaphic variables. CO₂ fluxes were the dominant contributor to total emissions, accounting for approximately 97.4% of the global warming potential (GWP), while CH₄ and N₂O together contributed less than 3%. The highest CO₂ emissions occurred in conventional systems during the growing stage in the wet zone (125.5 ± 11.41 mg C m⁻² h⁻¹). CH₄ generally acted as a sink, particularly in conventional systems in the dry zone (−12.58 ± 2.35 μg C m⁻² h⁻¹), although net emissions were detected in biodiverse systems in the wet zone (5.08 ± 1.50 μg C m⁻² h⁻¹). The highest N₂O fluxes were observed in conventional growing systems (32.28 ± 5.76 μg N m⁻² h⁻¹). GHG dynamics were mainly regulated by climatic factors—such as air temperature, relative humidity, and precipitation—and by key edaphic properties, including soil pH, soil organic carbon, soil temperature, and clay content. Projected GWP values ranged from 9.05 ± 2.77 to 40.9 ± 6.23 Mg CO₂-eq ha⁻¹ year⁻¹, with the highest values recorded in conventional systems in the growing stage. Overall, our findings underscore the potential of biodiversity-based agroforestry as a climate-smart practice to mitigate net GHG emissions in tropical cacao landscapes. Full article

The Príncipe Island is in the Gulf of Guinea, along the Cameroon Volcanic Line (West Africa). It is known worldwide for its biodiversity for whose conservation there is strong national and international consensus. But its geodiversity has played and continues to play a very important role in creating this unique habitat in sub-Saharan Africa, and represents an important asset in promoting local tourism, with a focus on the geological history of this remote island. The purpose of this study is to provide a comprehensive synthesis that is both up-to-date and inclusive, incorporating all the fundamental information and references on the geodiversity and the geological heritage of the Príncipe Island. The geological heritage of Príncipe Island is represented by ten geological heritage sites of different types (volcanological, geomorphological, sedimentological, and stratigraphical), and five viewpoints, whose geoheritage contents make it possible to support a narrative about the geological history of the Cameroon Volcanic Line that is of major relevance for the development of geoeducational resources and potentially appealing to fostering regional geotourism. Príncipe geological heritage sites were inventoried and assessed using the same qualitative methodology previously applied to the geological heritage of São Tomé Island, therefore making it possible to complete the country’s national inventory of geological sites, as well as to enrich the representation of African geoheritage among the world’s list of geological heritage sites. Full article

While archipelagos have a demonstrated role in the stepping-stone process of the global dissemination of Aedes-borne viruses, they are often neglected in epidemiological and modelling studies. Over the past 20 years, some Atlantic archipelagos have witnessed a series of Aedes-borne viral outbreaks, prompting inquiries into the local historical suitability for transmission. In this study, the climate-based suitability for transmission of Aedes-borne viruses between 1980 and 2019 across Madeira, the Canaries, Cape Verde, and São Tomé e Príncipe archipelagos was estimated. For each island, we characterized the seasonality of climate-based suitability, mapped the spatial landscape of suitability, and quantified the historical effects of climate change. Results show that both island-level suitability and the historical impact of climate change decrease with distance from the equator, while significant seasonality patterns are observed only in subtropical climates. This study provides a unique historical perspective on the role of climate in shaping Aedes-borne virus transmission potential in Atlantic archipelagos. The findings herein described can inform local public health initiatives, including human-based prevention, targeted viral surveillance, and mosquito control programs. Full article

Background: Dengue has emerged as a significant public health concern in Sao Tome and Principe, with the first documented outbreak occurring between 2022 and 2024. This study examined the epidemiological patterns, environmental determinants, and demographic characteristics of dengue transmission during this period. Methods: We conducted a comprehensive retrospective analysis of laboratory-confirmed dengue cases using national surveillance data, clinical records, and environmental monitoring data. Statistical analyses included demographic profiling, temporal trend assessment, and environmental correlation studies using multiple regression modeling. Results: Among 1264 laboratory-confirmed cases, we observed distinct age-specific vulnerability patterns, with the highest incidence rate in the 70–79 age group (829.6 per 100,000) despite most cases occurring in younger adults. Rainfall emerged as the strongest predictor of dengue transmission (r = 0.96, p < 0.001), explaining 92% of case variance in the regression model. Case distribution showed marked temporal variation, with 91.9% of cases reported in 2022, coinciding with exceptional rainfall (3205 mm). The overall case fatality rate was 0.71% (95% CI: 0.33–1.35), with significant quarterly variations. Geographical analysis revealed concentration in the Água Grande district (68.2% of cases). Conclusions: This first comprehensive analysis of dengue in Sao Tome and Principe demonstrates the crucial role of rainfall in disease transmission and reveals important age-specific vulnerability patterns. These findings provide an evidence base for developing targeted interventions, particularly during high-rainfall periods, and suggest the need for age-stratified clinical protocols in similar island settings. Full article

Aedes albopictus (Skuse, 1894), a mosquito originating in Asia, has been introduced to Africa since the 2000s. The mosquito is not only a nuisance but is capable of transmitting various arboviruses. The current study summarized our entomological surveys in the Democratic Republic of Sao Tome and Principe during 2000 to 2016. Adult mosquitoes were collected by sweep nets, human landing catches, and Centers for Disease Control (CDC) light traps, and the immatures were collected from water-filled habitats at 15 sentinel sites and reared to adulthood. Species identification was performed based on morphologic characteristics. Fragments of the cytochrome C oxidase subunit I (COI) and the Wolbachia surface protein (wsp) genes were amplified for mosquitoes collected in Principe. New records of four mosquito species were reported. Aedes albopictus was identified in 2015. The larvae were found distributed over the nation and were predominately in artificial water-holding containers (488/2698, 18.1%). The highest positive rate was observed in used tires in Príncipe (114/250, 45.6%). Mitochondrial DNA analysis revealed low genetic diversity among the invasive populations, but all tested specimens were superinfected by Wolbachia. The ability of Ae. albopictus to adapt to new environments and its involvement in disease transmission make the surveillance and control of this species particularly important. Full article

Like many other Small Island Developing States, São Tomé and Príncipe’s economy faces major weaknesses and constraints. These challenges are especially marked on the island of Príncipe, owing to its small size and double insularity. In recent decades, tourism, driven by international investment, has become a strategic sector for territorial development. This study assesses the suitability of this exogenous model and explores the feasibility of adopting a progressive change to a more community-centered tourism development model. Extensive fieldwork and multi-stakeholder collaboration have highlighted the need for a holistic, multi-dimensional strategy to secure this change. Such a strategy would prioritize local skills enhancement, infrastructure improvement, better governance and the diversification of tourism products and experiences. The gradual shift to a more endogenous approach in tourism development aims to strengthen sustainability across its multiple dimensions, ensuring more substantial and direct benefits for the local community and adding value to tourist services and experiences. Full article

This study characterizes the submerged geomorphology around Annobón, São Tomé, and Príncipe Islands, and the De Santarém–Escobar seamount in the Cameroon Volcanic Line or CVL (Gulf of Guinea, West Africa) through analyses of topographic relief and coastal bathymetry, and data from fieldwork and historical fossil collections. The clear relation between each submerged island and the seamount morphology of the CVL and the various stages of coral reef development according to Darwin’s subsidence hypothesis meets the concept of intangible geoheritage. This type of geoheritage is related to phenomena rather than to a thing, and it is usually highly evaluated by scientific communities. Academics tend to use science-based discourse to explain this theory, but it is rarely understood by non-specialist audiences. This work proposes a virtual geo-itinerary along the submerged geomorphology of the CVL islands and seamounts, which aims at telling the geohistory of the coral reefs’ origin and evolution according to Darwin’s theory, and disclosing its geoheritage contents for further sustainable uses. The resulting narrative can be used to support geotourism initiatives and to support the United Nations’ objectives for Small Island Developing States. Full article

This study presents for the first time an analysis of the content and chemical composition of the cuticular waxes and cutin in the leaves of the widespread and important tropical species Terminalia catappa. The leaves were collected in the equatorial Atlantic islands of São Tomé and Príncipe, in the Gulf of Guinea. The epicuticular and intracuticular waxes were determined via dichloromethane extraction and their chemical composition via GC-MS analysis, and the content and monomeric composition of cutin were determined after depolymerization via methanolysis. The leaves contained an epidermal cuticular coverage of 52.8 μg cm⁻² of the cuticular waxes (1.4% of mass) and 63.3 μg cm⁻² (1.5% of mass) of cutin. Cuticular waxes include mainly n-alkanols and fatty acids, with a substantial proportion of terpenes in the more easily solubilized fraction, and sterols in the more embedded waxes. Cutin is mostly constituted by C16 fatty acids and dihydroxyacids, also including aromatic monomers, suggesting a largely linear macromolecular arrangement. The high proportion of triacontanol, α-amyrin, β-amyrin, germanicol, and lupeol in the easily solubilized cuticular fraction may explain the bioactive properties attributed to the T. catappa leaves via the popular medicine, which allows us to consider them as a potential source for the extraction of these compounds. Full article

Background: Malaria is a parasitic infection transmitted by mosquito vectors, commonly found in tropical regions, and characterized by high morbidity and mortality. It causes a heavy disease burden in Sao Tome and Principe (STP), an island country in West Africa which at one time had a high incidence of malaria. Objective: This study aims to analyze the trend of disease burden of malaria in STP. Methods: The crude and age-standardized incidence, mortality, and disability-adjusted life years (DALYs) rate data of malaria were extracted from GBD 2019. Joinpoint 4.9 software was used to calculate the annual percentage change (APC) and the average annual percentage change (AAPC), which were also used to indicate the change in disease burden by different stages. Results: In general, the age-standardized incidence rate (ASIR), age-standardized mortality rate (ASMR), and age-standardized DALYs rate (ASDR) of malaria presented a decreasing trend between 1990 and 2019, with an average annual decrease of 5.6%, 6.2%, and 10.7%, respectively, in STP. Specifically, all indicators first presented an increasing trend from 1990 to about 2000, followed by a decreasing trend until 2019, although the incidence rebounded slightly after 2015. Overall, the ASIR, ASMR, and ASDR of malaria reduced by 77.08%, 87.84%, and 82.21%, respectively, in 2019 as compared to 1990. No significant differences in disease burden were found between males and females between 2005 and 2019. Children who were under 5 years old showed a relatively small decrease in the rate of DALYs as compared to other age groups, but remained the group with the highest disease burden of malaria in the country. Conclusions: The disease burden of malaria in STP showed a significant decrease between 1990 and 2019, but it will still be challenging to achieve the goal of eliminating malaria by 2025. The government and relevant authorities should aim to strengthen the prevention and surveillance of malaria and tailor population-specific interventions in order to reduce the disease burden of malaria in STP. Full article

Mangroves are critical to maintaining human well-being and global biodiversity. Eastern and western African shores present major environmental contrasts that reflect on mangrove forests’ structure and the ecosystem services they provide to human communities. This study compares the mangrove forest structure and condition, ecosystem services, and uses of resources in Maputo Bay (Mozambique in eastern Africa) and Príncipe Island (São Tomé and Príncipe in western Africa). Five mangrove species were identified in Maputo Bay, Avicennia marina, Bruguiera gymnorhiza, Ceriops tagal, Rhizophora mucronata, and Xylocarpus granatum, and the importance value index was higher for A. marina. Mangroves in Príncipe were exclusively dominated by Rhizophora harrisonii. In Maputo Bay, a weak regeneration characterized by a low quantity of seedlings was observed, although in Príncipe the sites were characterized by a low regeneration rate but well-established forests. The comparison of the mangrove structure between Maputo Bay and Príncipe Island presented statistically significant differences for mean DBH and height, whereas the trees in Príncipe presented higher values for both parameters. Strong human disturbance (through cutting) was identified in almost all sites in Maputo Bay but was rarely observed on Príncipe Island. In Maputo Bay, more than 90% of the coastal human community is involved in activities related to the surrounding mangroves, with a diversified exploitation of forest resources. On Príncipe Island, the exploitation of mangroves targets only tannin from the mangrove bark to dye fishing nets and small boats. The economic value of mangroves in Maputo Bay has subsistence and commercial importance, in contrast to Príncipe, which revealed no major economic value to the community. Full article

Biological invasions are considered one of the main extinction drivers of native species worldwide. Invasive species have detrimental effects on local ecosystems by means of competition, predation, habitat modification and nutrient cycling, as well as disease spreading. Along with ecological impacts, there are socio-economic consequences to human populations dependent on the services provided by these ecosystems. One of the most fundamental steps towards understanding the influence of invasive species is to determine their role on the local food web. The Mozambique tilapia (Oreochromis mossambicus) is an extremely aggressive opportunistic feeder that has a high biological and ecological plasticity, including flexible reproductive strategies (including mouthbrooding) and tolerance to a wide range of temperature, salinity and dissolved oxygen conditions. Its biological traits coupled with being used in aquaculture have made it a successful invader, widely distributed outside its native range. Yet, its populations have rarely been studied in the wild; hence, its potential impacts remain largely unknown. In this study, we investigate the diet of the invasive Mozambique tilapia in two mangroves of the oceanic island of São Tomé. We applied metabarcoding to simultaneously identify multiple taxa in tilapia gut content samples, using high-throughput sequencing. To achieve a greater taxonomic coverage, we combined the use of two barcodes, the 18S ribosomal RNA and the cytochrome C oxidase subunit I genes, to target phytoplankton and animal species, respectively. We found a total of 251 amplicon sequence variants belonging to 96 taxa. The results revealed diet differences between specimens from the two mangrove locations, not only regarding the level of biodiversity, but also in the frequencies of the occurrence of certain functional groups. Some taxa, such as diatoms, green algae and rotifers were found in the gut contents at both mangroves, whereas others, such as arthropods and mollusks, were almost exclusive to one of them. These findings provide useful insights into the ecological implications of the biological invasion of vulnerable island ecosystems, offering some specific guidance on how to minimize the impact of tilapia on the mangroves of the São Tomé Island. Full article

Mangroves have been recognized worldwide as crucial nursery areas for fish larvae and juveniles. Although they are critical for managing coastal fish stocks, information about larval fish communities in African island mangroves is scarce and these potential nursery areas in São Tomé Island have remained understudied. Fish larvae were collected over four weeks from October to November 2020 using light traps, passive plankton tows and seine nets in a multi-habitat approach. To overcome species identification constraints, both morphology and molecular analysis were considered. A total of 4 010 larvae were caught across all methods belonging to 16 families or 26 species. A few species dominated the ichthyoplankton community and the most abundant families were Cichlidae—especially the invasive Oreochromis mossambicus (47%)—and Gobiidae (43%), constituted by 7 taxa. The remaining 14 families only accounted for about 10% of total larvae captured. Three new species were recorded for the first time in the island mangroves and another three species were documented for the first time in the São Tomé Island. Taxa composition and richness varied considerably between sampling techniques. The highest taxa richness and diversity were recorded in the Malanza mangrove (25 species) while Praia das Conchas (9 species) was not able to sustain similar levels of biodiversity. Differences on fish larvae composition were found within the studied mangroves, depicting a strong influence of habitat type and a relative position within each system. These community composition patterns were marginally influenced by local environmental conditions such as temperature and dissolved oxygen. Overall, a total of eleven taxa have commercial interest and their presence as juveniles and larvae in São Tomé mangroves reinforces the need for conservation of these ecosystems and shows direct implications for the sustainability of the local fisheries. Full article

The forced migration of millions of Africans during the Atlantic Slave Trade led to the emergence of new genetic and linguistic identities, thereby providing a unique opportunity to study the mechanisms giving rise to human biological and cultural variation. Here we focus on the archipelago of São Tomé and Príncipe in the Gulf of Guinea, which hosted one of the earliest plantation societies relying exclusively on slave labor. We analyze the genetic variation in 25 individuals from three communities who speak distinct creole languages (Forros, Principenses and Angolares), using genomic data from expanded exomes in combination with a contextual dataset from Europe and Africa, including newly generated data from 28 Bantu speakers from Angola. Our findings show that while all islanders display mixed contributions from the Gulf of Guinea and Angola, the Angolares are characterized by extreme genetic differentiation and inbreeding, consistent with an admixed maroon isolate. In line with a more prominent Bantu contribution to their creole language, we additionally found that a previously reported high-frequency Y-chromosome haplotype in the Angolares has a likely Angolan origin, suggesting that their genetic, linguistic and social characteristics were influenced by a small group of dominant men who achieved disproportionate reproductive success. Full article

The rivers of São Tomé Island are colonized by Sicydium bustamantei (Greeff 1882), an amphidromous fish that spawns in those areas. After hatching, larvae drift to the ocean with the river flow. In the marine realm, the planktonic larvae develop and migrate to freshwater as post-larvae. The migrations of post-larvae support important local fisheries at the mouth of rivers in tropical volcanic islands. Amphidromous post-larvae rely on plankton as their main source of organic matter. However, the biology and ecology of S. bustamantei in the West African islands are understudied, despite its importance for local fisheries. Thus, this study aimed to start bridging this gap by studying its feeding ecology. Our objectives were to identify the main prey of S. bustamantei post-larvae, combining gut content with stable isotope analyses. The gut contents included zooplankton (Chaetognatha, Ostracoda, and unidentified crustaceans), debris from plant and/or macroalgae-derived material, and microplastics (including microfibers). The stable isotopes analysis indicated that zooplankton and macroalgae detritus were the main sources of organic matter assimilated by this species. We also demonstrated that S. bustamantei post-larvae are omnivorous and secondary consumers. These data provide pioneering information that can be used in management plans that still need to be developed. Full article

This article discusses the loss of the creole languages on São Tomé Island and the societal move from multilingualism to monolingualism in Portuguese. It argues that recognizing the ideologies attached to these languages is key in understanding the language shift, but also the processes leading toward monolingualism. This qualitative study is based on three main theories: Language as social practice, language ideology, and monoglot standardization. Data comes from ethnographic fieldwork and sociolinguistic interviews with 56 speakers from the capital of São Tomé and Príncipe. I argue that the existence of multilingualism on São Tomé Island is not valued at a societal level because of the pejorative ideologies that have been held about the creole languages since colonial times. Also, the use of the creole languages stood as a problem for the creation of a unified Santomean nation, as the different racial groups on the islands had their own creole. Results show how ideologies about the Portuguese language and its association with national unity, modernity, and European-ness favored its expansion on São Tomé Island and a move toward monolingualism. Full article