Monitoring arthropods under the scope of LIFE-BEETLES project – Baseline Data

Study Extent

A total of 45 sites were sampled in Flores, Pico and Terceira Islands. The sampling area consist on mixed-forests of endemic, native and exotic plant species and native forests. The main native and endemic species found in the area are Juniperus brevifolia, Ilex azorica, Laurus azorica, Erica azorica and Vaccinium cylindraceum. The exotic species found in the area are Pittosporum undulatum, Hedychium gardnerianum, and Eucalyptus globulus plantations

Sampling

Passive flight interception SLAM traps (Sea, Land and Air Malaise trap) were used to sample 31 selected sites between September 2020 and June 2023. This trap consists in a structure of 110x110x110 cm, where the trapped arthropods crawl up the mesh and then fall inside the sampling recipient (Borges et al. 2017). Each one is filled with propylene glycol (pure 1,2-PROPANODIOL) to kill the captured arthropods and conserve the sample between collections. Although this protocol was developed to sample flying arthropods, by working as an extension of the tree, non-flying species such as spiders can also crawl into the trap (Borges et al. 2017, Lhoumeau et al. 2022), enhancing the range of groups that can be sampled by this technique. Because of this, previous studies have used these traps to analyse diversity and abundance changes in the arthropod communities in Azores pristine forest sites (Matthews et al. 2019, Borges et al. 2020, Lhoumeau and Borges 2023). The samples were collected every 90 consecutive days in native forest plot and every 180 consecutive days in mixed forest between September 2020 and March of 2023. Additionally, we collected epigean arthropods using pitfall traps for a minimum of two weeks during the summers of 2020, 2021, 2022, and 2023. These traps have been shown to effectively sample the epigean arthropod fauna (Borges et al. 2005). The pitfall traps were plastic cups with a top diameter of 42 mm and a depth of 78 mm, placed in the ground so that the lip of the cup was level with the surface. Each transect was equipped with 15 traps spaced 5 m apart. Approximately 60 ml of a non-attractive solution (anti-freeze liquid) with a small proportion of ethylene glycol and a few drops of liquid detergent filled the traps. The traps were shielded from rain by a white plastic plate fixed to the ground with two pieces of wire, positioned about 5 cm above the surface. The arthropod samples were then taken to the laboratory and transferred to 96% ethanol.

Quality Control

All sorted specimens were identified by a taxonomical expert in laboratory.

Method steps

1. Each sample was meticulously labeled and stored, with archive samples remaining accessible for additional data verification and analysis.

Classes: Arachnida, Chilopoda, Diplopoda, Insecta Orders: Araneae, Blattodea, Julida, Coleoptera, Lithobiomorpha, Hemiptera, Lepidoptera, Pseudoscorpiones, Opiliones, Psocodea, Hymenoptera, Thysanoptera, Geophilomorpha, Archaeognatha, Polydesmida, Dermaptera, Orthoptera, Scolopendromorpha, Neuroptera, Trichoptera, Scutigeromorpha, Polyxenida, Chordeumatida, Phasmida

1. Arthropoda
   common name: Arthropods rank: phylum

Flores, Pico and Terceira Islands, Azores, (Portugal)