Dataset of butterfly monitoring in Sierra Nevada (Spain)

Study Extent

The network of transects in Sierra Nevada is distributed from 700 to 3,100 m a.s.l. in nine types of ecosystems, broadly characterized as: aquatic systems (occupying less than 1% of the transects), grasslands, rocky high mountains ecosystems (27%), high mountain wet pastures (4%), high mountain scrub dominated by high mountain scrublands (35%), holm oak woods (2%), medium mountain pastures (9%), medium mountain scrub (8%), coniferous plantations (less than 1%), pyrenean oak forests (11%) and Pinus sylvestris autochthonous pine forests (2%).

Sampling

Sampling method consists of a walk transect based on the method proposed by Pollar and Yates (1994) that is the most widely used method in this type of studies. This method consists in counting every butterfly along the transect within a 5 meters band at each side of the observer and also 5 meters above and ahead. Transects average length were 1,900 meters (300 to 3,270 m). The butterflies were mainly visually identified, but a butterfly net has been used in the cases when the visual identification was not possible. Every captured butterfly was released at the same place where it had been catched once it was identified. All the identifications were made at the species levels except for some individuals that only could be identified at Genus level.

Quality Control

A) Digitalization and storage: all data is stored in a normalized database in the Information System of Sierra Nevada Global-Change Observatory, whose data entry form includes several validation rules. B) Taxonomic validation: Lepidoptera scientific names were checked with the updated checklist of the European Butterflies (Wiemers et al., 2018), available in GBIF (Maes et al., 2020). C) Standardisation: the standardisation to Darwin Core was done according to the practices recommended by the TDWG guidelines (https://dwc.tdwg.org/terms/).

Method steps

1. The original database is stored in the Information System of Sierra Nevada Global-Change Observatory.
2. The dataset was standardised to the Darwin Core structure (Wieczorek et al., 2012) as sampling event data. It contains, specifically: 10,369 records of events (1,725 parent events and 8,644 child events), 34,137 records of occurrences, and 4,852 records of associated measurements (wind, cloud cover, air temperature). The parent events refer to the transect sampling whereas the child events correspond to each section sampling (transects are divided into sections, and butterflies are counted separately in each section). The Darwin Core elements included in the Event Core are: eventID, parentEventID, modified, language, institutionCode, ownerInstitutionCode, datasetName, license, continent, country, countryCode, verbatimLocality, eventDate, year, month, day, eventTime, samplingProtocol, sampleSizeValue, sampleSizeUnit, minimumElevationInMeters, maximumElevationInMeters, habitat, decimalLatitude, decimalLongitude, geodeticDatum, georeferenceRemarks, footprintWKT. For the Occurrence Extension are: occurrenceID, catalogNumber, collectionCode, eventID, eventDate, recordedBy, organismQuantity, organismQuantityType, lifeStage, basisOfRecord, scientificName, taxonRank, kingdom, phylum, class, order, family, genus, specificEpithet, infraSpecificEpithet, scientificNameAuthorship. For the Measurement or Fact Extension table, the Darwin Core elements included are: measurementID, eventID, measurementType, measurementValue, measurementUnit, measurementMethod.
3. The resulting dataset was published through the Integrated Publishing Toolkit of the Spanish node of the Global Biodiversity Information Facility (GBIF) (http://ipt.gbif.es).

This dataset includes a total of 34,137 occurrence records of the order Lepidoptera, which compile the butterfly counts by species and section. In total, 101,424 individuals of butterflies were recorded since 2008, belonging to 102 species and 1 subspecies. There are 64 genera and 5 families represented in this dataset.

1. Pieridae
   rank: family
2. Lycaenidae
   rank: family
3. Hesperiidae
   rank: family
4. Papilionidae
   rank: family
5. Nymphalidae
   rank: family

Sierra Nevada (SE Spain) is one of the southernmost highest mountain ranges of Europe. It comprises an elevation range from 270 to 3,492 m a.s.l. and it extends along 100 km from west to east in parallel to the Mediterranean coast line, with a notable increase of aridity towards the eastern sector. Sierra Nevada presents a notable environmental heterogeneity, not only in its elevational gradient, but also in its different orientations and in the west-east gradient. The five Mediterranean bioclimatic belts are represented here: thermo, meso, supra, oro and crioro-Mediterranean. A forest belt occupies good part at the middle and lower elevations and presents an uneven state of transformation, while certain extensions of holm oaks still persist (on siliceous environments and also on carbonate soils), relictic Pyrenean oak forests and some native pine forests of Pinus sylvestris and Pinus pinaster, the presence of more than 30,000 ha of reforestation pine forests is also noteworthy. Above the tree line there are 30,000 ha of typical mediterranean mountain scrubland mainly compounded by species of the genus Genista, Juniperus, Berberis and Hormatophila among others. On the upper belts, rocky landscapes defined by recent glacial events alternates with high mountain grasslands and 74 glacial lakes distributed in an elevation range situated between 2,600 and 3,100 m a.s.l. The high mountain area comprises more than 30 summits that reach an elevation above 3,000 m a.s.l. During more than the half of the year, these areas remain under a snow cover and this fact conditions a good part of the ecological processes there. The high mountain ecosystem of Sierra Nevada holds a huge number of plant and animal endemism, representing a hotspot within the mediterranean hotspot. Sierra Nevada hold some of the higher protections figures for a natural area in Spain and in Europe, so it was declared as a Natural Park since 1989 and as a National Park since 1999, is also designated as a UNESCO Biosphere Reserve (since 1986), as a Natura 2000 network site (since 2006) and holds the distinctive Green List awarded by the IUCN in recognition of good management practices.