IMIS

All mainland Portuguese provinces and all districts but one (Évora) were investigated. A total of 761 dolichopodid samples were collected in 278 sampling sites distributed over 87 municipalities and 182 localities, with nearly ¾ of the samples gathered by sweepnet. In terms of generic representation, the Portuguese dolichopodid fauna occupies an intermediate position between those of northwestern European and other Mediterranean countries. Despite the large amount of data gathered, the dolichopodid fauna of Portugal remains insufficiently known and a considerable number of additional known and new species can be expected with continued sampling. A more exhaustive description of the dataset and the results of the surveys can be found in Pollet et al. (2019).
The following sampling strategy was applied by Rui Andrade and Ana Gonçalves (together they gathered about 88% of the samples): the focus of collecting during fieldwork was on various dipteran families with Dolichopodidae as one of the target taxa. Both researchers aimed at collecting all over Portugal to fill gaps in the known distribution of species. For practical reasons, a large number of sites were visited near Porto, and some of them were investigated on multiple occasions and/or during longer periods of time. For more distant collecting trips, mostly protected areas were selected on the assumption that good habitat types for Diptera were present. Rui Andrade steadily sampled Diptera in humid sites; e.g., along banks of streams and rivers, but also visited drier places in order to get a reliable idea of the extant Diptera richness. Collecting was carried out throughout the year with samples taken during every month. Most samples were collected in June, May and September (in decreasing numbers), whereas the first two and last two months of the year each produced 10 or fewer samples. About 72% of the samples and more than 86% (including those collected by Marc Pollet and Anja De Braekeleer) of the specimens were collected by sweep net which was used to gather flies from all kinds of surfaces; e.g., rocks, muddy and sandy soil, but also from tree trunks. Yellow pan traps and hand collecting accounted for 12% and 11% of the samples respectively, and produced about 6% and 7% of the specimens respectively. The other collecting methods (light trap, Malaise trap, observation, pan trap of unknown colour, pooter, rearing) together contributed about 2% (= 17) of the samples and only 0.7% (n = 47) of the specimens.
Samples were retrieved from all 11 Portuguese provinces, and all districts except for Évora. In terms of number of municipalities, localities and locations, the districts of Bragança, Guarda and Faro were best covered. Next to Bragança and Guarda, the largest number of sampling sites was situated in the Porto and Coimbra districts. Over 1/3 of all samples were gathered in the Porto district, whereas more than 5% originated from (in decreasing order) Braga, Bragança, Coimbra, Guarda, Aveiro and Faro. More than 30% of the sampling sites were situated between 501 and 1,000 m a.s.l., with about 15% of them in or near the littoral zone (0–10m), and between 201 and 500 m a.s.l. The surveys in mainland Portugal were mainly conducted by Portuguese researchers between 2009 and 2016. Belgian researchers contributed to a far smaller extent: Marc Pollet (Belgium) and Anja De Braekeleer (Belgium) visited Portugal in May 2014, and Jonas Mortelmans (Belgium) added a few samples from 2018. The general aim of this project was to get a first comprehensive account of the dolichopodid fauna of mainland Portugal (thus far only 34 species had been recorded from the country). A total of 789 samples were ultimately investigated, 761 of which contained Dolichopodidae. Not taking the 53 samples collected by Marc Pollet & Anja De Braekeleer into account, between 2009 and 2016 on average 88 samples were collected per year, with peaks of 150 and 146 in 2011 and 2013 respectively, and a minimum of 46 in 2012.
There was little need for any quality control during the sampling phase of this project. Collecting was mainly executed in promising sites for Diptera. A subsample of representative Diptera species (incl. Dolichopodidae) was systematically retrieved from the sweepnet by Rui Andrade and Ana Conçalves (principal collectors), whereas all Dolichopodidae were retained by Marc Pollet and Anja De Braekeleer. All samples were stored in 75% alcohol solution in cool and dark conditions.