Arthropods from Praia da Vitória (Terceira, Azores, Portugal)

Study Extent

This study covers a small coastal area with 5 km extension between PPV and PPCP

Sampling

In each site, arthropods were sampled during summers of 2016 and 2017 using a combination of standardized methods inspired by the COBRA protocol ( Cardoso 2009 ): -Nocturnal active aerial searching (AAS) – Four samples were obtained by four trained collectors (Paulo Borges, Mariana Brito, Rosalina Gabriel, César Pimentel) targeting active arthropods found above knee-level by hand, forceps, pooter or brush, immediately transferring them into vials containing alcohol. All the time spent in searching (one hour per researcher) was accounted for. -Foliage Beating (FB) – During day time ten samples of each main tree or brush were sampled. A 110 cm × 80 cm sheet with a frame was used as a drop-cloth (beating tray) and a wooden pole of at least 1.5 m was used to beat tree branches, as high as possible. The plants selected were: and in PPV and PPCP, and and in PBJ. In 2017, in addition, two samples during night (FSN) were obtained (one hour each sample covering several plants). -Foliage sweeping (FS): – A round sweep net with an opening diameter of 46 cm was used to sweep bushes and tall herbs. All time spent sweeping or searching for dislodged arthropods was accounted for. Two samples during day time (FSD) were obtained (one hour each samples). In 2017, in addition, two samples during night (FSN) were obtained (one hour each sample). -Pitfall (PIT) – Pitfall traps (4.2 cm wide at the top, and approximately 7.2 cm deep) were placed immediately outside the perimeter of each lake, spaced 10 meters. Traps were filled with 3 – 4 cm of 100% propylene glycol and left in the field for seven days. Traps were protected from predation, inundation with rain water, and unwanted vertebrate capture by using plates sitting on stilts 2 cm above the ground surface. In PBJ two transects were performed with 30 traps in the main transect and 15 traps in a secondary transect covering a small stream. In PPV and PPCP single transects of 30 traps each were setup in the margins of water bodies. In PPV half of the traps were in the margins of the largest “island”. In 1017 additional traps were setup in Cerrado São Lazaro (PPV205 Paul da Praia Vitória). For each site a total of four samples of AAS, 20 samples of FB, two samples of FS and 30 main samples of PIT were obtained, totaling 56 samples per site and an overall 168 samples in 2017. Still in 2017, additional pitfall traps in PBJ small stream added 15 more samples totalling 183 samples. The main 56 samples per site included the sampling of two main sub-habitats, the aerial vegetation with 26 samples (20 beatings during the day, two sweeps during the day and four nigh aerial searches) and the ground habitat with 30 pitfall samples. In 2017 the additional samples made during the night added four samples for each site, totalling 60 samples per site.

Quality Control

The correct identification of the sampled taxa is crucial. Taxonomic nomenclature followed the Borges et al. 2010 checklist.

Method steps

1. (1) for arthropod orders for which there was taxonomic expertise, one of us (CP) performed morphospecies sorting using a parataxonomy approach (see Oliver and Beattie 1993) with a reference collection
2. (2) a trained taxonomist (PAVB) corrected all the splitting and lumping errors and identified most of the species
3. 3) the morphospecies for which it was not possible a correct identification were sent to experts for identification

Arthropods including Diplopoda, Chilopoda, Arachnida (Opiliones; Pseudoscorpiones; Araneae) and Hexapoda (Microcoryphia; Zygentoma; Odonata; Orthoptera; Phasmatodea; Dermaptera; Psocoptera; Hemiptera; Thysanoptera; Neuroptera; Coleoptera; Lepidoptera; Hymenoptera -Formicidae)

1. Animalia
   rank: kingdom
2. Arthropoda
   rank: phylum
3. Arachnida
   rank: class
4. Insecta
   rank: class

Terceira Island (area: 400.6 km²; elevation: 1,021.14 m) is one of the nine islands from the Azores archipelago, located in the North Atlantic, roughly at 38°43′49″N 27°19′10″W. The climate in the Azores is temperate oceanic, with regular and abundant rainfall, with high levels of relative humidity and persistent winds, mainly during the winter and autumn seasons. Terceira Island is known for the presence of some very important pristine areas at high elevation (Gaspar et al. 2011). However, few natural areas still remain at lower elevations, notably in Praia da Vitória’s council. Three wet areas, Paul da Praia da Vitória (PPV), Paul do Belo Jardim (PBJ) and Paul da Pedreira do Cabo da Praia (PPCP) were studied in this project. Coastal vegetation dominates, namely Juncus acutus, and still includes some arboreal cover by the native shrub Morella faya. The Erica-Morella coastal woodlands as described in Elias et al. 2016 are not present and the exotic invasive species Arundo donax is very common. The PPV was a large coastal salty marshland with associated dunes, which was largely transformed and reduced for urban development and underwent several dynamic changes in the last 500 years of human occupation. After some major work performed between 2006 and 2010, PPV is currently characterized by a large waterbody with islands of Juncus acutus isolated by channels. PBJ was originally one of the largest dune areas from the Azores, but after the construction of the Paria da Vitória Harbor was reduced to a very small wet area, with a dune covered partially by J. acutus. Of particular relevance is the presence of a small stream adding some diversity of vegetation and arthropods. The case of PPCP is completely different, since this is a recently created wetland, resulting from the removal of large amounts of stones for the construction of the Praia da Vitória harbor, around 1980. As a consequence a new ecosystem was created, the quarry of Cabo da Praia.