Long-term monitoring of the distribution and abundance of diurnal butterflies (Papilionoidea) in Doñana 2007-2022

Study Extent

The study area is located in southwest Spain in the Guadalquivir Basin and covers Doñana Protected Area (542.51 km2). Climate is Mediterranean sub-humid with Atlantic coast influence deriving in wet mild winters and dry warm summers. The rainy season occurs between October and April, with a peak in December–January (average rainfall is about 550 mm). Several ecosystems are monitored in order to study optimal habitats for butterflies in general, but also some specific places and habitats for determinates species or groups of them are monitored. Briefly, this protocol covers up wooded areas (mainly pine and oaks forests and Juniperus thickets), shrublands (black and white Andalusian brushes) and grasslands (xeric, humid and with amphibious conditions). This monitoring program has carried out in 14 different and permanent transects. The transects are divided in several sections in order to distinguish the differences in microhabitats conditions.

Sampling

The long-term monitoring of diurnal butterflies (Papilionoidea) in Doñana, south-western Spain, was initiated in 2005, but until 2007 the protocol is not well stablished, that is why the temporal range of this dataset start in December of 2007 with one transect. From this first transect, in 2008 the Monitoring Program of Natural Resources and Processes applied the BMS methodology to new zones and transects. The principals aims of this protocol were: to invent all species of diurnal butterflies that inhabits in Doñana, in order to detect the appearance of new species or local extinction of some populations; and know the dynamics and variations of butterflies populations between years and between months, in order to detect declines in these animal populations. The monitoring was based on the survey of different transects: During the first period of the monitoring, between 2007 and 2013, seven transects had been sampled. But in the second period, 2014-2018, the survey had been increased with seven new transects and also five of the “old” transects of the previous sampling period, this is a total of 12 transects surveyed between 2014 and 2018; and 14 transects in all of the long-term monitoring. The transects are divided into sections with a different or equal length, that usually correspond to different habitat areas. These sections are related to the EUNIS habitat classification (version 2012) and to SACRE habitat classification. Along the 46 different transect sections there are a total of 11 different habitats, that covers nearly all habitats of the Doñana’s natural space (END). The distance covered by transects was between 460 and 1175 metres. Along the distance of each transect, according the sections and its habitat all butterflies that appear in an imaginary cube of five metres side had been counted and identified.

Quality Control

The protocol has been supervised by ecological researchers and the data have been validated by the members who performed the transects.

Method steps

1. Following the Butterfly Monitoring Scheme (BMS) and Pollard's transects, the data collection is based in walking transect of a determinate distance where the observer must note, count and identify (and also sex the individuals when it is possible) all butterflies that fly in an imaginary cube of 5 meters of side. In the period 2007-2013, the data was collected with the software CyberTracker and all the individuals have a coordinate associated; but since 2014 the data collection was changed to BMS that is why individuals recorded in this period (2014-2022) did not have a coordinate, and the registers are associated to different sections of the transect. The transect was adapted to optimal period of butterflies' day activity, that is three or four hours before and after noon, always with suitable climatic conditions: no rain and/or fog, minimum temperature between 13 on sunny days and 17ºC on cloudly days, maximum temperature below 30 ºC and wind conditions under 5 in Beaufort's scale. In order to know environmental and meteorological variables, temperature, wind conditions (Beaufort's scale) and cloud coverage (eighths of cloud coverage) were measured at the beginning and at the end of each transect. The distance of transect varies between 460 and 1170 metres. The time to complete the transects varies depending on the number of individuals observed in each one, but time values are usually between 10 and 75 minutes.

N/A

1. Chordata
   rank: phylum
2. Soleidae
   rank: family
3. Pleuronectiformes
   rank: order
4. Animalia
   rank: kingdom
5. Perciformes
   rank: order
6. Sparidae
   rank: family

The study area is Doñana National Park, south-west of Spain, which is one of the two areas of distribution of this species in the south of Spain. Doñana Protected Area includes seven ecosystems types (coastal waters, beach, dunes, forest, shrubland, sandy lakes and marshes) and 21 habitat types, 11 of them of high conservation importance – such as the Bulrush and Glasswort marsh, floodplain lakes, sandy lakes, grassland ecotones, Cork-Oak forest, shrubland, coastal Juniper forest and dunes. Tortoises are usually present along the border of temporal marshes and between dunes with vegetation composed by mediterranean scrub, scattered oaks and pine trees of medium and low cover.