Arthropod traits as proxies for abundance trends in the Azorean Islands

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 abundan..., We carried out this study in the Azores Archipelago, which encompasses nine volcanic islands and several islets and seamounts. The archipelago is located in the northern Atlantic Ocean, approximately between 37° and 40° N latitude and 24° and 31° W longitude, spread along a distance of approximately 615 km from East to West. The archipelago is divided into three distinct island groups: western (Corvo and Flores), central (Faial, Pico, São Jorge, Graciosa, and Terceira), and eastern (São Miguel and Santa Maria). On all islands, the climate is characterized as temperate oceanic with high levels of relative atmospheric humidity, which can reach 95% in the elevated native semi-tropical evergreen laurel forest (Elias et al. 2016, Borges et al. 2022a, b, c). Human presence on these islands, dating back to the 15th century, has significantly altered the landscape (Norder et al. 2020). The once-pristine native forests have given way to exotic tree plantations, agricultural and pastoral fields, ..., , # Azorean arthropod abundance trends and species traits and Bayesian model script

[https://doi.org/10.5061/dryad.qv9s4mwpf](https://doi.org/10.5061/dryad.qv9s4mwpf)

## Description of the data and file structure

The data used for the Bayesian analysis of Azorean arthropod species and their traits. The species data were derived from samplings on the Azorean Islands for the past 25 years. However, this compilation and methods used to evaluate species is novel. Each line is an independent species.

* Order: Indicate the arthropod order.
* Morpho: Indicate the species or morpho-species number.
* Origin: Indicate if the species is endemic, native non-endemic, or exotic in Azores.
* Body size: Indicate the body size of the species. Values were standardized by each arthropod order.
* Diet: Indicates what is the species' trophic level, indicating if it is a carnivore, herbivore, or omnivore.
* Dispersal ability: Indicate how is the main source of dispersal for this species, if it flies, ballo...