During a LIFE project dedicated to the implementation of the conservation of the habitats and restoration of coastal wet areas of Praia da Vitória (Terceira, Azores, Portugal), there was the opportunity to study several groups of arthropods in three wet areas: Paul da Praia da Vitória (PPV), Paul do Belo Jardim (PBJ) and Paul da Pedreira do Cabo da Praia (PPCP). The objective of the study was to perform a rapid biodiversity assessment, comparing the three sites in two different years, before and after the implantation of several conservation measures. This project contributed also to improve the knowledge of Azorean arthropod diversity at both local and regional scales also including new taxa for Terceira island and new records for Azores. Taking into consideration those aims, a set of standardised sampling methods were performed inspired by the COBRA protocol originally developed for spiders. A total of 15,810 specimens belonging to 216 arthropod species and subspecies were collected. Beetles (Insecta, Coleoptera) and spiders (Araneae) dominate, with 81 and 51 taxa respectively. Two beetle families dominate, Staphylinidae and Curculionidae with respectively 22 and 17 species and subspecies. Exotic species also dominate with 131 species and subspecies, the Azorean endemic taxa being restricted to only eight taxa. The remaining 77 species and subspecies are native non-endemic. A total of six species are novel for the Azores (five exotic and one possibly native) and an additional 15 taxa are novel for Terceira island (9 exotic and 6 native).

The data presented here comes from samples collected as part of two recent research projects (ISLANDBIODIV and MACDIV), which aimed to understand the drivers of community assembly in Macaronesian islands. We applied the sampling protocol COBRA (Conservation Oriented Biodiversity Rapid Assessment, Cardoso 2009) in ten 50 m x 50 m native forest plots in the Azorean Islands of Pico (6 plots) and Terceira (10 plots) to assess the diversity of spiders species. Through this publication we contribute to the knowledge of the arachnofauna of the Azores, and more specifically, to that of the islands of Pico and Terceira. This dataset presents data generated from spider samples collected in 16 forest plots on the Azorean islands of Pico and Terceira. Of the 40 species collected, 16 were introduced, 13 endemic, seven native (five of them Macaronesian endemics) and four undescribed species. Although most of the species had been previously recorded on both islands, two of the introduced species were recorded in Pico for the first time.

The data we present are part of the long-term project SLAM (Long Term Ecological Study of the Impacts of Climate Change in the natural forest of Azores) that aims to understand the impact of biodiversity erosion drivers on Azorean native forests. Passive flight interception SLAM traps (Sea, Land and Air Malaise trap) were used to sample forest plots in both islands, with one trap being setup at each plot. A total of twenty 50m x 50m plots were sampled in two of the islands from the archipelago, 13 in Terceira and 7 in Pico. This publication contributes not only to a better knowledge of the arachnofauna present in native forests of Terceira and Pico, but also contributes to understand the patterns of abundance and diversity both seasonally and between years.