[Description of methods used for collection/generation of data] The long-term monitoring of carnivore tracks in Doñana is part of a harmonised protocol for the Long-term Ecological Monitoring Program of Natural Resources and Processes targeting mammals' populations. The general aim of this protocol is to study the temporal evolution of the relative density of the main species of carnivores in the main habitats of the Doñana National Park. Tracks surveys were done annually after the first rains of the hydrological year, i.e. the first autumn rains, usually in October. Due to climate change, in recent years the rainy season has been delayed until the beginning of the year. This protocol has stablished in 2007 and it has done annually until the present (2022), except in 2021 when due to logistical problems no census was made. Censuses are carried out through 12 prefixed transect, with sand substrate, in Doñana National Park. Each transect consists of a 2 km of length and 1.5 m of width that is done by a car at a constant speed between 10 and 15 km/h. Transects are cleaned the day before of the census with a metal beam to facilitate the read of the tracks and to ensure that the foot prints were from the previous day. Each transect is repeated in three consecutive days, and during the transect the sand is cleaned for the next day. In the census an expert in mammals’ tracks identifies all the tracks, i.e. groups of carnivore foot prints, and he/she records them in Cybertracker. That way, tracks' information like coordinates, hour, species identification and observation was recorded; and also the information of each transect was recorded: sampler, drivers, date, start and end (hour and coordinates). This method enables to calculate Kilometric Abundance Indexes (KAI) for each species and transect. In order to clarify all carnivore datasets, the data was separated by species, this allows concrete analysis by species. In this dataset Eurasian otter´s (Lutra lutra) data is presented.

The long-term monitoring of carnivore tracks in Doñana is part of a harmonised protocol for the Long-term Ecological Monitoring Program of Natural Resources and Processes targeting mammals' populations. The general aim of this protocol is to study the temporal evolution of the relative density of the main species of carnivores in the main habitats of the Doñana National Park. Tracks surveys were done annually after the first rains of the hydrological year, i.e. the first autumn rains, usually in October. Due to climate change, in recent years the rainy season has been delayed until the beginning of the year. This protocol has stablished in 2007 and it has done annually until the present (2022), except in 2021 when due to logistical problems no census was made. Censuses are carried out through 12 prefixed transect, with sand substrate, in Doñana National Park. Each transect consists of a 2 km of length and 1.5 m of width that is done by a car at a constant speed between 10 and 15 km/h. Transects are cleaned the day before of the census with a metal beam to facilitate the read of the tracks and to ensure that the foot prints were from the previous day. Each transect is repeated in three consecutive days, and during the transect the sand is cleaned for the next day. In the census an expert in mammals’ tracks identifies all the tracks, i.e. groups of carnivore foot prints, and he/she records them in Cybertracker. That way, tracks' information like coordinates, hour, species identification and observation was recorded; and also the information of each transect was recorded: sampler, drivers, date, start and end (hour and coordinates). This method enables to calculate Kilometric Abundance Indexes (KAI) for each species and transect. In order to clarify all carnivore datasets, the data was separated by species, this allows concrete analysis by species. In this dataset Eurasian otter´s (Lutra lutra) data is presented.

We acknowledge financial support from National Parks Autonomous Agency (OAPN) in 2007; the Singular Scientific and Technical Infrastructures from the Spanish Science and Innovation Ministry (ICTS-MICINN); the Ministry of Agriculture, Livestock, Fisheries and Sustainable Development from the Regional Government of Andalusia (CAGPDES-JA) since 2011; the Doñana Biological Station from the Spanish National Research Council (EBD-CSIC) since all the study period (2011); the Ministry of Environmetal sustainability and blue economy from the Regional Goverment of Andalusia since 2017 with the LIFE-ADAPTAMED project; Ministry of Science and Innovation (Recovery, Transformation and Resilence Plan); and the European Comision with the Long-term Ecosystem Research in Europe (eLTER) (a HORIZON funding coordination of the European funding programme for research and innovation) and NextGenerationEU funding.

1. icts-rbd-LutraTracks_ev_20230915: eventID, institutionCode, institutionID, datasetName, eventDate, year, month, day, verbatimEventDate, eventTime, country, continent, countryCode, stateProvince, county, municipality, locality, verbatimLocality, verbatimCoordinates, geodeticDatum, samplingProtocol, SampleSizeValue, sampleSizeUnit, samplingEffort and eventRemarks. 2. icts-rbd-LutraTracks_occ_20230915: eventID, occurrenceID, collectionCode, , decimalLatitude, decimalLongitude, dynamicProperties, basisOfRecord, recordedBy, occurrenceStatus, individualCount, identifiedBy, scientificName, verbatimScientificName, kingdom, phylum, class, order, family, genus, specificEpithet, scientificNameAuthorship, taxonRank, organismQuantity, organismQuantityType and occurrenceRemarks.

Dataset are structured following well-established data formats. Two files are provided and they are related to each other with the variable eventID. The first file (icts-rbd-LutraTracks_ev_20230915) contains the information of each event (time of occurrence, geographical coordinates or sampling effort); the second file (icts-rbd-LutraTracks_occ_20230915) contains the count of tracks for each species recorded in each site, numbers of tracks recorded and taxonomic classification.

[Methods for processing the data] The data was recorded in CyberTracker sequence. The protocol used has been supervised by researchers and the data have been validated by the members who performed the sampling. The raw data was processed with Excel.

Peer reviewed