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- Arthropod traits as proxies for abundance trends in the Azorean IslandsPublication . Oyarzabal, Guilherme; Cardoso, Pedro; Rigal, François; Boieiro, Mário; Santos, Ana M. C.; Amorim do Rosário, Isabel; Malumbres-Olarte, Jagoba; Costa, Ricardo; Lhoumeau, Sebastian; Pozsgai, Gabor; Gabriel, Rosalina; Borges, Paulo A. V.Human activities drive ecological transformation, impacting island ecosystems from species diversity to ecological traits, mainly through habitat degradation and invasive species. Using two unique long-term datasets we aim to evaluate whether species traits (body size, trophic level, dispersal capacity and habitat occupancy) can predict temporal variations in the abundance of endemic, indigenous (endemic and native non-endemic) and exotic arthropods in the Azores Islands. We found that body size is crucial to predict arthropod abundance trends. Small-bodied herbivorous arthropods showed a decrease in abundance, while large-bodied indigenous arthropods increased in abundance, mainly in well-preserved areas. Also, large-bodied exotic arthropods increased in abundance across the entire archipelago. Moreover, endemic canopy dwellers increased in abundance, while endemic ground-dwellers decreased in abundance. Simultaneously, exotic arthropods showed the opposite result, increasing in abundance in the ground while decreasing in abundance in the canopy. Finally, habitat influenced both endemic and exotic spider abundance trends. Endemic spiders that occupy solely natural habitats experienced a decline in abundance, while exotic spiders in the same habitats increased in abundance. Our study underscores the significance of arthropod species traits in predicting abundance changes in island ecosystems over time, as well as the importance of monitoring species communities. Conservation efforts must extend beyond endangered species to protect non-threatened ones, given the increased extinction risk faced by even common species on islands. Monitoring and restoration programs are essential for preserving island ecosystems and safeguarding endemic arthropod populations.
- The drivers of plant turnover change across spatial scales in the AzoresPublication . Leo, María; Rigal, François; Ronquillo, Cristina; Borges, Paulo A. V.; Azevedo, Eduardo Brito; Santos, Ana M. C.Beta diversity patterns are essential for understanding how biological communities are structured. Geographical and environmental factors, as well as species dispersal ability, are important drivers of beta diversity, but their relative importance may vary across spatial scales. In this study, we evaluate whether beta diversity changes across geographical scales and analyse how different drivers affect turnover patterns of native seed plants in an oceanic archipelago, the Azores (Portugal). Using a 500 × 500 m resolution grid, we selected cells that are covered by one of the following habitats: native forest, naturalized vegetation and seminatural pastures. We calculated species turnover at three spatial scales: 1) between islands, 2) between cells within each island, and finally 3) between cells of each of the habitats of interest in each island. We then calculated the contribution of dispersal syndromes (endozoochory, epizoochory, hydrochory and anemochory) to turnover at each of the scales. Lastly, we assessed the relationship between geographical and climatic distances and habitat type with turnover. Turnover was higher at the smallest spatial scale, particularly in seminatural pastures, and decreased with increasing spatial scales, a pattern potentially associated with the historical fragmentation and current patchy distribution of native forest and seminatural habitats in the Azores. Dispersal syndromes and habitat type had a negligible effect on turnover at all scales. Geographical distance had a positive effect on turnover at all scales, increasing its importance with scale. The relationship between turnover and climatic distance was only significant at the intermediate and small scales in specific islands and habitats. Therefore, scale plays an important role at determining the effect of the drivers of turnover, in particular geographical and climatic distance. These results highlight the need to carefully select the scale of analysis when studying turnover patterns, as well as identifying the potential drivers associated with each spatial scale.
- The BALA project: A pioneering monitoring of Azorean forest invertebrates over two decades (1999–2022)Publication . Pozsgai, Gabor; Lhoumeau, Sébastien; Rosário, Isabel Amorim Do; Boieiro, Mário; Cardoso, Pedro; Costa, Ricardo; Ferreira, Maria Teresa; Leite, Abrão; Malumbres-Olarte, Jagoba; Oyarzabal, Guilherme; Rigal, François; Ros Prieto, Alejandra; Santos, Ana M. C.; Gabriel, Rosalina; Borges, Paulo A. V.Globally, there is a concerning decline in many insect populations, and this trend likely extends to all arthropods, potentially impacting unique island biota. Native non-endemic and endemic species on islands are under threat due to habitat destruction, with the introduction of exotic, and potentially invasive, species, further contributing to this decline. While long-term studies of plants and vertebrate fauna are available, long-term arthropod datasets are limited, hindering comparisons with better-studied taxa. The Biodiversity of Arthropods of the Laurisilva of the Azores (BALA) project has allowed gathering comprehensive data since 1997 in the Azorean Islands (Portugal), using standardised sampling methods across islands. The dataset includes arthropod counts from epigean (pitfall traps) and canopy-dwelling (beating samples) communities, enriched with species information, biogeographic origins, and IUCN categories. Metadata associated with the sample protocol and events, like sample identifier, archive number, sampled tree species, and trap type are also recorded. The database is available in multiple formats, including Darwin Core, which facilitates the ecological analysis of pressing environmental concerns, such as arthropod population declines and biological invasions.
- Dung beetles of Azorean cattle-grazed pasturelands - data of the DUNGPOOL projectPublication . Duenas-Rojas, Almudena; Cuesta, Eva; Parmentier, Laurine Marie; Leite, Abrão; Borges, P.A.V.; Coelho dos Santos, Ana Margarida; Soares, AntónioABSTRACT: The data we present are part of the project DUNGPOOL, which aims to evaluate the effects of the species pool, community assembly processes and increasing temperatures on the local diversity and ecosystem functions performed by dung beetles in island and mainland cattle-grazed pasturelands. By combining replicated field experiments on the Iberian Peninsula with parallel work on three mid-Atlantic islands (Pico, Faial and Terceira, Azores), the project exploits the natural contrast between a species-rich mainland pool and the species-poor, largely exotic island pools, to test explicit biodiversity–ecosystem-function (BEF) hypotheses across spatial scales. From June to July 2024, dung beetles were sampled in 84 locations of the three islands of the Azores Archipelago (Portugal), using 306 pitfall traps baited with fresh cow dung.
- Species traits may predict extinction risk of Azorean endemic arthropodsPublication . Oyarzabal da Silva, Guilherme; Cardoso, Pedro; Rigal, François; Canelas Boieiro, Mário Rui; Coelho dos Santos, Ana Margarida; Amorim do Rosário, Isabel; Malumbres-Olarte, Jagoba; Costa, Ricardo; Lhoumeau, Sébastien Georges André; Pozsgai, Gabor; Gabriel, Rosalina; Borges, Paulo; Littlewood, Nick; Bahlai, ChristieABSTRACT: Oceanic islands, recognised for their isolation, high endemic species richness and unique evolutionary paths compared with their continental counterparts, are extremely susceptible to anthropogenic activities. The fragmentation of island habitats and disruption of native ecosystems has increased the risk of extinction for many endemic species, including arthropods. Extinction is not random, and some species traits may increase the probability of species entering an extinction trajectory. Studying species traits alongside International Union for Conservation of Nature (IUCN) threat levels may offer valuable insights into their vulnerability and inform targeted conservation strategies. Here, we aim to test the predictability of IUCN threat categories and conservation status based on endemic Azorean arthropods' functional traits: body size, trophic group and vertical strata occupancy. We demonstrate that species with limited vertical occupancy, particularly those restricted to ground level, are more vulnerable to extinction than those that inhabit the forest canopy. Contrary to our expectations, body size and trophic group did not appear to be direct predictors of the threat level. Overall, our findings underscore previous and ongoing effects of human activities in island ecosystems. Hence, we emphasise the need to look at species traits as predictors of future extinctions in endemic island arthropods.
- Threats and conservation status of the endemic terrestrial arthropods of the AzoresPublication . Oyarzabal da Silva, Guilherme; Pozsgai, Gabor; Tsafack, Noelline; Cardoso, Pedro; Rigal, François; Canelas Boieiro, Mário Rui; Coelho dos Santos, Ana Margarida; Amorim do Rosário, Isabel; Malumbres-Olarte, Jagoba; Costa, Ricardo; Lhoumeau, Sébastien Georges André; Gabriel, Rosalina; Borges, P.A.V.ABSTRACT: Insular ecosystems are disproportionately threatened by human activities, leading to an unprecedented decline in species diversity, particularly on remote archipelagos like the Azores. However, the impacts of humans on arthropods, which typically represent a big proportion of island biotas, remain poorly documented. We present an assessment of threats affecting different groups of species, examining the relationship between species occupancy, IUCN threat categories and trophic interactions for arthropods in the Azores (Macaronesia). We compiled data on endemic arthropods from published lists and IUCN assessments, including extinction risk, direct threats, and geographical ranges, to identify key pressures on species. Using network analyses, we examined the association between extinction risk and number of species, also estimating the IUCN Red List Index (RLI) for each island conservation status. We found that some of the Azorean endemic arthropod species have already gone extinct and more than half are classified as threatened by the IUCN Red List. Of these, predatory beetles (Coleoptera) and spiders (Araneae) have the highest numbers of threatened species, mainly due to habitat degradation, the spread of invasive plant species, and climate change. The RLI differs greatly among islands, being the lowest in Santa Maria, which concentrates a large number of critically endangered (CR) single-island endemic species, and higher in islands with larger and better-preserved native forest fragments, such as Terceira. A comprehensive approach integrating habitat protection, invasive species management and conservation measures is essential to ensure the long-term survival of Azorean arthropod endemic species in particular and island biota in general.