A checklist of the land Mollusca (Gastropoda) of the islands of São Tomé and Príncipe, with new records and description of new taxa

The first comprehensive checklists since the works of Germain in 1916 are presented for the terrestrial mollusca of São Tomé and Príncipe. The fauna currently known comprises 59 species for São Tomé, 45 for Príncipe, and a total of 86 species in the country as a whole. Seven species of terrestrial Gastropoda are newly described from the island of São Tomé and six more from the island of Príncipe. The genera involved are Cyathopoma (Cyclophoridae), Maizania and Thomeomaizania (Maizaniidae), Pseudoveronicella (Veronicellidae), Nothapalus (Achatinidae), Gulella and Streptostele (Streptaxidae), Truncatellina (Truncatellinidae), Afroconulus (Euconulidae), Principicochlea n. gen., Principotrochoidea n. gen., Thomithapsia n. gen. and Thomitrochoidea n. gen. (Urocyclidae). Most of these are from natural forest habitats and are likely to be singleisland endemics. Aporachis n. gen. (Achatinidae s.l.) and Apothapsia n. gen. (Helicarionidae) are also described to accommodate previously known species. Rachis burnayi (Dohrn) and R. eminula (Morelet) are placed in the genus Gittenedouardia. Additional new island records are of ten species on São Tomé, one on Príncipe and two more on both islands. These include six species of “microgastropods” with wider ranges in tropical Africa that are likely to be hitherto overlooked parts of the indigenous fauna and six anthropogenic introductions. Pseudopeas crossei previously known only from Príncipe and Bioko is newly recorded on São Tomé. More detailed taxonomic notes are provided on identification and delimitation of species and genera in Cyclophoridae/ Maizaniidae, Veronicellidae, Achatinidae, Cerastidae, Helicarionidae, and on the forgotten but apparently valid Pseudoveronicella thomensis (Veronicellidae).info:eu-repo/semantics/publishedVersio

An endemic‐rich island through the eyes of children: Wildlife identification and conservation preferences in São Tomé (Gulf of Guinea)

Species that the public knows and is willing to protect often do not align with international conservation priorities. Assessing perceptions on wildlife is thus essential to guide conservation initiatives, especially in island developing states where native and introduced species often have contrasting values for biodiversity. We used a game to assess the ability of third class students in São Tomé Island (São Tomé and Príncipe, central Africa) to identify wildlife and their conservation preferences. Students correctly identified 28% of the animals shown. Children who were poorer, male or from rural schools were more likely to correctly identify species. Urban children were less successful identifying species endemic to São Tomé and Príncipe than rural children. Conservation preferences were not associated with species identification and instead were justified by subjective species-specific traits, such as attractiveness or profitability. Despite the low identification rates for endemic (10% correct identifications) and threatened birds (2%), children were keen on preserving endemic species, indicating that these might become effective flagships for the unique biodiversity of the island. These results illustrate the need to consider separately the attributes that affect knowledge and willingness to protect, and how both can be used to guide conservation strategies.info:eu-repo/semantics/publishedVersio

A tale of two species: the importance of native ecosystems for long-term conservation on Príncipe Island, Gulf of Guinea

Since it was first described in 1901, the Príncipe thrush Turdus xanthorhynchus has been rare and restricted to the native forest in the south of Príncipe Island. The Obô giant land snail Archachatina bicarinata, however, was widespread across the island and at least locally abundant until the 1990s. Since then its population has collapsed, and now, like the thrush, it is also restricted to the native forest in the south of the island. Using species distribution modelling, we show that both species are currently strongly associated with rugged and remote areas of native forest at high altitudes. We argue that their current distribution might be negatively affected by anthropogenic pressures, as both are harvested, and also because invasive alien species are expected to have deleterious effects on these species, although further studies are needed to clarify interactions between these native and introduced species. The diachronic stories of these species highlight an overlooked value of native ecosystems: their role in the conservation of widespread species that might be unable to use anthropogenic landscapes in the future. They also reinforce the need for protected areas that strive to exclude most human activities in the context of particularly sensitive biodiversity, as is often the case on oceanic islands.info:eu-repo/semantics/publishedVersio

Biological invasion and the conservation of endemic island species: São Tomé Archachatina giant snails (Pulmonata: Achatinidade)

Tese de mestrado em Biologia da Conservação, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2017A perda global de biodiversidade é uma das maiores consequências das atividades humanas. As ilhas são hotspots mundiais de biodiversidade, com elevado grau de espécies endémicas, mas os seus ecossistemas são também dos mais suscetíveis às alterações antrópicas. A introdução de espécies exóticas é a principal causa de extinções em ilhas, agravada quando em sinergia com outros fatores, como a alteração do tipo de uso do solo. Os moluscos são um dos grupos animais com mais extinções, e os caracóis terrestres, em particular, sofreram o maior número de extinções devido às atividades humanas. Estes organismos são excelentes bioindicadores da qualidade do habitat, exatamente porque são muito vulneráveis às alterações ambientais. Por outro lado, também existem diversas espécies de caracóis terrestres com grande capacidade invasora, e que se adaptam muito bem a habitats humanizados. A introdução de várias espécies de caracóis gigantes africanos (géneros Achatina e Archachatina) fora do continente resultou em danos na agricultura, problemas sanitários e ameaças para os ecossistemas nativos. Estes animais têm hábitos noturnos, são polífagos e hermafroditas, produzindo grandes quantidades de ovos, sendo muito procurados para fins medicinais, ornamentais, como animais de estimação e, por fim, pelo considerável valor, sobretudo no território africano, como recurso alimentar. A ilha de São Tomé está situada a 255 km da costa Oeste africana, no Golfo da Guiné, e tem uma área de 857 km2. É caraterizada por uma elevada humidade e precipitações que podem chegar até aos 7000 mm anuais no Sudoeste. As temperaturas médias anuais variam entre os 22 e os 30°C, com mínimas de 10°C em elevada altitude. Originalmente dominada por floresta, intensas modificações da paisagem ocorreram desde a sua descoberta e colonização, no final do século XV. Podemos atualmente identificar um gradiente de degradação ambiental ao longo da ilha: áreas não florestadas sobretudo junto à costa, seguidas por plantações de sombra, onde se cultiva o cacau e o café, a floresta secundária, que resulta em grande parte do abandono de antigas plantações e onde plantas nativas e exóticas coexistem e, por fim, a floresta nativa, nas zonas mais inacessíveis do interior da ilha, que permanece quase intocada pelas atividades humanas e alberga uma elevada taxa de espécies endémicas. Apesar da sua reduzida extensão territorial, a ilha é reconhecida internacionalmente pelo elevado número de endemismos em diversos grupos taxonómicos, tais como aves, anfíbios, plantas superiores, morcegos, répteis, borboletas e moluscos. Destes últimos, São Tomé conta com 40 espécies de moluscos, 31 dos quais são endémicos. O caracol gigante do Golfo da Guiné Archachatina bicarinata (Bruguière, 1792), ou búzio-d’Obô, é uma espécie endémica das ilhas de São Tomé e Príncipe e tem sofrido um declínio acentuado em ambas as ilhas nas últimas décadas. A introdução do caracol gigante do Oeste africano Archachatina marginata (Swainson, 1821), ou búzio-vermelho, está entre as prováveis causas desse declínio. No primeiro capítulo desta tese avaliamos quais os fatores que explicam a distribuição do caracol gigante introduzido em São Tomé. O amplo gradiente de degradação ambiental que existe na ilha providencia condições excelentes para se compreender as ligações entre a distribuição desta espécie e a humanização da paisagem. Verificámos que este caracol existe em quase toda a ilha, preferindo plantações e florestas secundárias de baixa altitude, e evitando as zonas de floresta nativa. A sua presença está associada a plantas introduzidas, típicas de ecossistemas degradados, e a sua população encontra-se em expansão, com elevada proporção de indivíduos juvenis, em especial nas zonas mais degradadas. Este estudo é uma contribuição essencial para o planeamento de medidas de conservação que visem limitar a ação da espécie invasora nos ecossistemas mais suscetíveis da ilha e serve também como um alerta para a necessidade de proteger a sua floresta nativa e as espécies que nela habitam. No segundo capítulo avaliamos as possíveis interações entre o caracol gigante nativo e o invasor. Recolhemos diversos relatos que associam 31o desaparecimento do endémico à expansão do invasor ao longo do tempo. Documentamos uma forte segregação entre as duas espécies em termos espaciais, sendo que o endémico se encontra restrito às florestas nativas mais remotas, enquanto que o invasor se encontra maioritariamente em áreas mais degradadas, ocupando uma proporção muito mais significativa da ilha. As duas espécies estão associadas a vegetações totalmente diferentes, estando a endémica associa13da a flora endémica, e a introduzida a flora exótica, por sua vez igualmente associada a habitats antrópicos. A população atual do búzio-vermelho é composta por uma elevada proporção de juvenis, em contraste com a do endémico, em que claramente predominam os adultos. Finalmente, registámos diferenças nos padrões de atividade diária de ambas as espécies, com o endémico a ser principalmente diurno e o invasor a preferir estar ativo durante a noite. Os nossos resultados sugerem que o declínio acentuado do búzio-d’Obô pode estar relacionado com a introdução do búzio-vermelho, representando o primeiro estudo dedicado à ecologia e distribuição destas espécies em São Tomé. Este estudo sugere que o grau de ameaça do búzio-d’Obô deve ser aumentado, bem como a necessidade urgente de implementar medidas de ação de conservação que assegurem a sua sobrevivência.The global loss of biodiversity is a major consequence of human activities. Habitat destruction and the introduction of non-native species are among the principal drivers of this loss. Knowing the ecology of invasive species, namely their habitat preferences, distribution and potential interactions with local biodiversity, is thus fundamental for ecosystem management and for minimizing negative impacts. São Tomé Island holds an endemic-rich land snail fauna, including the Vulnerable Gulf of Guinea Giant Land Snail Archachatina bicarinata (Bruguière, 1792). This species was relatively widespread and abundant in the island, but its population has suffered a steep decline since mid-twentieth century. The introduction of the West African Giant Land Snail A. marginata (Swainson, 1821) has been implied in this decline, but very little is known about its dispersal or about its effects on native species. This thesis aims to assess the links between the dispersal of the introduced giant snail and human-modified ecosystems, and if this species is displacing the endemic giant snail. We found that the introduced giant snail is widely distributed throughout most of the island, preferring lowland plantations and other modified ecosystems rich in introduced plants. There was a strong spatial segregation between the two species, the endemic being restricted to the most remote patches of native forest. The invasive appeared to be expanding, having a large proportion of juveniles in its population, while the endemic showed the opposite trend. We also observed a temporal displacement between the occurrence of the two species: the endemic being active mostly during the day and the invasive principally around dusk and dawn. This was the first study on the ecological interaction between these two species. The small overlapping area in their distributions and the perceptions of local inhabitants suggest that the introduced snail is displacing the endemic. Gain01ing a better understanding of the mechanisms underlying this invasion process is essential to prevent its spread into the native forest. Immediate conservation actions aimed to preserve the endemic snail are necessary to halt its dramatic population collapse, which may warrant an uplisting of its conservation status

Snails, forest and people : ecology and conservation of terrestrial molluscs in the Gulf of Guinea oceanic islands, central Africa

Anthropogenic activities are increasingly shaping ecosystems worldwide, threatening the functioning of global ecological processes that maintain life on Earth. Endemic-rich areas, such as oceanic islands, hold unique biotas and socio-ecological systems, which are particularly susceptible to habitat degradation and biological invasions. Terrestrial molluscs comprise a highly diverse taxonomic group which support critical ecosystem functions but have suffered some of the highest extinction rates. The oceanic islands of the Gulf of Guinea host a high proportion of single-island endemic terrestrial mollusc species that remain little studied. This thesis explores the links between terrestrial molluscs, their habitats, and the people living in the Gulf of Guinea oceanic islands, using a combination of techniques from social and ecological sciences. The islands hold 96 species of terrestrial mollusc, 65% of which are endemic. On the largest island, São Tomé, land-use intensification decreased native species richness and abundance, while it promoted introduced species, such as the invasive Archachatina marginata. This species was an important source of food and income, especially for vulnerable people in rural areas, where it was also widely preferred and recognized by children. Wildlife conservation preferences were mainly justified by species attractiveness or profitability, and male, poorer children from rural areas were more likely to correctly identify animal species. The endemic A. bicarinata is the only terrestrial mollusc from the islands that has been listed as threatened, and most of its genetic diversity was found on Príncipe Island. This thesis showed that habitat loss and introduced species are important threats to this malacofauna, and that maintaining the integrity of forest ecosystems is critical to preventing invasions, but also that management for conservation will have to consider the relevance of introduced species for people. Urgent in and ex situ efforts are needed to protect the valuable forests where most endemic molluscs persist

Land‐use intensification promotes non‐native species in a tropical island bird assemblage

Habitat loss and non-native species are two key drivers of biodiversity decline. The importance of their interactions is widely recognized, but remains poorly understood. We used the endemic-rich bird assemblage of São Tomé Island to study this type of interactions. We built species-specific binomial generalized linear models for 33 terrestrial bird species, based on presence–absence data from 2398 sampling points. Meta-analysis techniques revealed that land use was more important in explaining distribution than topographic variables, rainfall, or distance to coast for the studied bird species. Native species were more likely to occur in remote rainy forests at higher altitudes, whereas non-native species were more likely to occur in non-forested ecosystems, being associated with humanized lowland areas in the drier flat regions of São Tomé. The susceptibility of anthropogenic ecosystems to the establishment of non-native birds suggests that disturbance favours these species. An analysis of species feeding guilds further suggests that these habitat associations might be linked to resource availability, as a large proportion of non-native species rely on seeds, which are clearly more available outside the best-preserved forests. Contrarily, very few native birds seem to be using this resource, and instead rely on more complex ecological interaction, such as carnivory and frugivory. This difference may reduce the chance of negative interactions between native and non-native species (e.g. competition), but this should not be misunderstood for a lack of negative effects of the latter. Our results indicate that land-use intensification is the key driver of biodiversity changes on São Tomé, potentially facilitating the expansion of non-native species and demoting ecological complexity. Therefore, protecting the best-preserved forests is the single most important measure to ensure the conservation of native species.info:eu-repo/semantics/publishedVersio