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A expansão antropogénica nas zonas costeiras, aliada às alterações climáticas e à ocorrência pontual de fenómenos naturais destrutivos, representa uma ameaça significativa para várias espécies endémicas insulares, que possuem áreas de distribuição muito reduzidas e limitada capacidade de evasão. Azorina vidalii (H.C. Watson) Feer (Campanulaceae) e Lotus azoricus P.W. Ball (Fabaceae) são duas espécies costeiras endémicas dos Açores atualmente ameaçadas, recentemente incluídas em projetos de conservação, como o LIFE VIDALIA, que contemplaram ações de reforço populacional. No entanto, subsistem lacunas consideráveis no conhecimento sobre estas espécies, com estudos existentes focados apenas em aspetos isolados da sua biologia. Este trabalho propõe uma abordagem holística que integra ecologia, genética populacional e biologia reprodutiva, com o objetivo de apoiar a conservação das espécies e avaliar os impactos genéticos dos reforços populacionais recentemente realizados. Azorina vidalii ocorre em todas as ilhas do arquipélago, enquanto L. azoricus tem uma distribuição mais restrita, ocorrendo apenas nas ilhas de Santa Maria, Pico e São Jorge. Foram amostradas populações de ambas as espécies nas nove ilhas, com recolha de dados morfológicos e moleculares, inventário florístico, e levantamento de variáveis ambientais, climáticas e de ameaças locais. Foram utilizados métodos diretos e indiretos para avaliar as estratégias reprodutivas de A. vidalii, incluindo o tipo de sistema de autoincompatibilidade e o sucesso reprodutivo. Para a análise genética de L. azoricus, empregaram-se técnicas clássicas de extração e amplificação de DNA, utilizando retrotransposões, um tipo de marcador molecular dominante. Os resultados indicam que a vegetação costeira onde ocorrem estas espécies é limitada pelo mar e por atividades humanas, como infraestruturas costeiras, agricultura, pastoreio, turismo, presença de espécies invasoras, herbivoria, erosão costeira e submersão marítima. A. vidalii apresenta um nicho ecológico mais amplo, enquanto L. azoricus prefere habitats elevados, com clima quente e seco — condições que ocorrem quase exclusivamente em Santa Maria, justificando a sua maior raridade. Foi detetada alguma mistura genética em L. azoricus, incluindo um efeito fundador artificial numa população reforçada pelo projeto LIFE VIDALIA. A diferenciação genética entre populações foi baixa, com exceção da população de São Lourenço (Santa Maria), onde foi mais acentuada. O fluxo genético foi elevado entre populações do grupo central, possivelmente devido a mecanismos naturais ou assistidos de dispersão. Verificou-se um aumento da diversidade genética nas populações reforçadas; no entanto, no caso da população da Calheta de Nesquim, onde se observou regeneração natural após remoção de invasoras, o reforço populacional revelou-se desnecessário. Foram identificadas populações com elevada riqueza alélica, que devem ser priorizadas em futuras ações de conservação. Azorina vidalii revelou variação morfológica floral associada à geografia insular, e a ocorrência das diferentes fases fenológicas mostrou-se dependente do clima. As flores apresentaram plasticidade na duração das fases sexuais, resultando numa dicogamia incompleta. Polinizações experimentais realizadas na população natural dos Mosteiros (ilha de São Miguel) revelaram uma estratégia reprodutiva mista, com ausência de autopolinização espontânea, fecundação dependente de polinizadores, autoincompatibilidade parcial e ocorrência de endogamia. Ambas as espécies foram classificadas como “ameaçadas” segundo os critérios da União Internacional para a Conservação da Natureza (IUCN). Conclui-se que a abordagem holística adotada constitui uma ferramenta metodológica valiosa, permitindo a formulação de recomendações concretas para uma conservação mais eficaz e informada destas duas espécies endémicas costeiras dos Açores.
ABSTRACT: Anthropogenic expansion in coastal areas, combined with climate change and the occasional occurrence of destructive natural phenomena, poses a significant threat to several endemic island species, which have very small distribution areas and limited evasion capacity. Azorina vidalii (H.C. Watson) Feer (Campanulaceae) and Lotus azoricus P.W. Ball (Fabaceae) are two endangered coastal species, endemic to the Azores. They have recently been included in conservation projects, such as LIFE VIDALIA, which have performed population reinforcement actions. However, considerable gaps remain in knowledge about these species, with existing studies focusing only on isolated aspects of their biology. This work proposes a holistic approach that integrates ecology, population genetics, and reproductive biology, with the aim of supporting species conservation and assessing the genetic impacts of recent population reinforcements. Azorina vidalii occurs on all islands of the archipelago, while L. azoricus has a more restricted distribution, occurring only on the islands of Santa Maria, Pico, and São Jorge. Populations of both species were sampled on the nine islands, with the collection of morphological and molecular data, a floristic inventory, and a survey of environmental, climatic, and local threat variables. Direct and indirect methods were used to assess the reproductive strategies of A. vidalii, including the type of self-incompatibility system and reproductive success. For the genetic analysis of L. azoricus, classical DNA extraction and amplification techniques were employed, using retrotransposons, a dominant molecular marker. The results indicate that the coastal vegetation where these species occur is limited by the sea and human activities, such as coastal infrastructure, agriculture, grazing, tourism, the presence of invasive species, herbivory, coastal erosion, and sea submersion. A. vidalii has a broader ecological niche, while L. azoricus prefers highland habitats with a hot, dry climate—conditions that occur almost exclusively in Santa Maria, explaining its greater rarity. Some genetic admixture was detected in L. azoricus, including an artificial founder effect in a population reinforced by the LIFE VIDALIA project. Genetic differentiation between populations was low, with the exception of the São Lourenço (Santa Maria) population, where it was more pronounced. Gene flow was high between populations in the central subarchipelago, possibly due to natural or assisted dispersal mechanisms. Increased genetic diversity was observed in the reinforced populations; however, in the Calheta de Nesquim population, where natural regeneration was observed after invasive species removal, population reinforcement proved unnecessary. Populations with high allelic richness were identified and should be prioritized in future conservation efforts. Azorina vidalii revealed floral morphological variation associated with island geography, and the occurrence of different phenological phases was shown to be climate-dependent. The flowers exhibited plasticity in the duration of the sexual phases, resulting in incomplete dichogamy. Experimental pollinations conducted in the natural population of Mosteiros (São Miguel Island) revealed a mixed reproductive strategy, with no spontaneous self-pollination, pollinator-dependent fertilization, partial self-incompatibility, and the occurrence of inbreeding. Both species were classified as "threatened" according to the criteria of the International Union for Conservation of Nature (IUCN). In conclusion, the holistic approach used here constitutes a valuable methodological tool, enabling the formulation of concrete recommendations for more effective and informed conservation of these two coastal endemic species of the Azores.
ABSTRACT: Anthropogenic expansion in coastal areas, combined with climate change and the occasional occurrence of destructive natural phenomena, poses a significant threat to several endemic island species, which have very small distribution areas and limited evasion capacity. Azorina vidalii (H.C. Watson) Feer (Campanulaceae) and Lotus azoricus P.W. Ball (Fabaceae) are two endangered coastal species, endemic to the Azores. They have recently been included in conservation projects, such as LIFE VIDALIA, which have performed population reinforcement actions. However, considerable gaps remain in knowledge about these species, with existing studies focusing only on isolated aspects of their biology. This work proposes a holistic approach that integrates ecology, population genetics, and reproductive biology, with the aim of supporting species conservation and assessing the genetic impacts of recent population reinforcements. Azorina vidalii occurs on all islands of the archipelago, while L. azoricus has a more restricted distribution, occurring only on the islands of Santa Maria, Pico, and São Jorge. Populations of both species were sampled on the nine islands, with the collection of morphological and molecular data, a floristic inventory, and a survey of environmental, climatic, and local threat variables. Direct and indirect methods were used to assess the reproductive strategies of A. vidalii, including the type of self-incompatibility system and reproductive success. For the genetic analysis of L. azoricus, classical DNA extraction and amplification techniques were employed, using retrotransposons, a dominant molecular marker. The results indicate that the coastal vegetation where these species occur is limited by the sea and human activities, such as coastal infrastructure, agriculture, grazing, tourism, the presence of invasive species, herbivory, coastal erosion, and sea submersion. A. vidalii has a broader ecological niche, while L. azoricus prefers highland habitats with a hot, dry climate—conditions that occur almost exclusively in Santa Maria, explaining its greater rarity. Some genetic admixture was detected in L. azoricus, including an artificial founder effect in a population reinforced by the LIFE VIDALIA project. Genetic differentiation between populations was low, with the exception of the São Lourenço (Santa Maria) population, where it was more pronounced. Gene flow was high between populations in the central subarchipelago, possibly due to natural or assisted dispersal mechanisms. Increased genetic diversity was observed in the reinforced populations; however, in the Calheta de Nesquim population, where natural regeneration was observed after invasive species removal, population reinforcement proved unnecessary. Populations with high allelic richness were identified and should be prioritized in future conservation efforts. Azorina vidalii revealed floral morphological variation associated with island geography, and the occurrence of different phenological phases was shown to be climate-dependent. The flowers exhibited plasticity in the duration of the sexual phases, resulting in incomplete dichogamy. Experimental pollinations conducted in the natural population of Mosteiros (São Miguel Island) revealed a mixed reproductive strategy, with no spontaneous self-pollination, pollinator-dependent fertilization, partial self-incompatibility, and the occurrence of inbreeding. Both species were classified as "threatened" according to the criteria of the International Union for Conservation of Nature (IUCN). In conclusion, the holistic approach used here constitutes a valuable methodological tool, enabling the formulation of concrete recommendations for more effective and informed conservation of these two coastal endemic species of the Azores.
Descrição
Tese de Doutoramento, Biologia, 13 de abril de 2026, Universidade dos Açores.
Palavras-chave
Reproductive biology Population genetics Ecology Azorina vidalii Lotus azoricus Conservation
Contexto Educativo
Citação
REGO, Rúben Miguel Correia. (2026). A holistic approach to the conservation of the coastal Azorean endemic taxa Lotus azoricus and Azorina vidalii: Reproductive biology, population genetics and ecology. Ponta Delgada: Universidade dos Açores, 2026. 311 p. Tese de Doutoramento em Biologia. Disponível em http://hdl.handle.net/10400.3/8971