Long-term monitoring of lizards and geckos in Doñana 2005-2021

Lizard and gecko counts are collected annually by members of the monitoring team three times per year in the periods when reptile activity is high (two samplings in March-June and one sampling in September-October), with good environmental conditions (temperature between 17 and 25 ºC and absence of rain or strong wind conditions). The method used to record the presence and abundance of lizard and gecko species (kilometric index: number of individuals/km) are the transect censuses. Individuals are visually searched along seven transects (linear or circular) that are carried out by one trained person on foot. Each transect have an established length, but the length surveyed is different (averaged 1858 ± 51.86 meters). Each transect is located in dunes or mediterranean vegetation habitats, representative of Doñana ecosystems. Two transects runs through wooden footpaths (within the Natural Park and five transects are placed on sand-trails (4 within the National Park and one in Natural Park which contains a small part of wooden footpath). Linear transects have been surveyed in the outward track direction and after waiting 15 minutes it has been again performed on the way back. This information is valid to account for species presence in the area. However, we suggest to choose the first survey performed for statistical analyses that require independence of samples.
Eight species can be potentially observed during the samplings: Mediterranean house gecko (Hemidactylus turcicus), Common Wall Gecko (Tarentola mauritanica), Fringe-fingered Lizard (Acanthodactylus erythrurus), Algerian Psammodromus (Psammodromus algirus), Western Psammodromus (Psammodromus occidentalis), Carbonell's wall lizard (Podarcis carbonelli), Andalusian wall lizard (Podarcis vaucheri), Ocellated lizard (Timon lepidus). Other reptile species present in Doñana have not been included in this study as the detection with this method is very low. For instance, to detect species with a fossorial behaviour (the Mediterranean Worm Lizard Blanus cinereus) or those cryptic as adders (Vipera latastei), it is required larger investment of survey which consist in looking under vegetation, burrows or logs (there are not stones in Doñana).
Data recorded during the surveys include weather description (cloud cover, temperature, rain, or wind speed), species identification, number of individuals, sex and life stage of the reptiles when possible, as well as time and georeferenced data of the observation. Between 2005-2007 data was registered in Excel file and since 2008 data is recorded with the app CyberTracker (see protocol).
The protocol used has been supervised by herpetological researchers and the data have been validated by the members who performed the transects.