Author: Rocío Márquez Ferrando
Keywords: Samplingevent, Occurrence, Transect, Long-term monitoring, Mediterranean Spur-Thighed Tortoise

Long-term monitoring of the distribution and relative abundance of the Mediterranean Spur-Thighed Tortoise (Testudo graeca) in Doñana 2005-2023

Ana C. Andreu^1, Rosa Arribas^1, Isidro Román^2, Luis Alfonso Ramírez^3, David Paz^4, Diego López^4, Ricardo Díaz-Delgado^1, Javier Bustamante^5, Rocío Márquez-Ferrando^1, Javier Bustamante^1

1 Estación Biológica de Doñana (CSIC), C/ Américo Vespucio 26,  Isla de la Cartuja, 41092, Sevilla, Spain; 2 Estación Biológica de Doñana (CSIC), C/ Américo Vespucio 26,  Isla de la Cartuja, 41092, Sevilla, Spain; 3 ICTS-Reserva Biológica de Doñana, Carretera de El Rocío - Matalascañas, A-483, km 40, 21760, Almonte, Spain; 4 Estación Biológica de Doñana (CSIC), Carretera de El Rocío - Matalascañas, A-483, km 40, 21760, Almonte, Spain; 5 Estación Biológica de Doñana (CSIC), C/ Américo Vespucio 26,  Isla de la Cartuja, 41092, Sevilla

Corresponding author(s): Ana C. AndreuRosa Arribas (rosa.arribas@ebd.csic.es)Isidro RománLuis Alfonso Ramírez (luisramirez@ebd.csic.es)David Paz (davidpaz@ebd.csic.es)Diego LópezRicardo Díaz-Delgado (rdiaz@ebd.csic.es)Javier Bustamante (jbustamante@ebd.csic.es), Rocío Márquez-Ferrando (rociomarquez@ebd.csic.es)

Received {date}; Revised {date}; Accepted {date}; Published {date}

Citation: Combination of authors, year of data paper publication (in parentheses), Title, Journal Name, Volume, Issue number (in parentheses), and doi of the data paper.

Resource Citation

Andreu A C, Arribas R, Román I, Ramírez L A, Paz D, López D, Díaz-Delgado R, Bustamante J, Márquez-Ferrando R (2023). Long-term monitoring of the distribution and relative abundance of the Mediterranean Spur-Thighed Tortoise (Testudo graeca) in Doñana 2005-2023. Version 2.2. Estación Biológica de Doñana (CSIC). Samplingevent dataset. https://doi.org/10.15470/el0cyi https://doi.org/10.15470/el0cyi

Abstract

This dataset includes records of the monitoring of the distribution and relative abundance of the Mediterranean Spur-Thighed Tortoise (Testudo graeca) in Doñana since 2005 as part of the monitoring program of natural resources and processes in Doñana. One of the aims of this project was to obtain a temporal and continuous series of data of the distribution and abundance of this species to detect changes and trends in the population within the protected area.

Keywords: Samplingevent, Occurrence, Transect, Long-term monitoring, Mediterranean Spur-Thighed Tortoise

Project details

Project title: Seguimiento a largo plazo de los procesos naturales en la Infraestructura Científica y Técnica Singular Reserva Biológica de Doñana
Personnel: Ricardo Díaz-Delgado, Javier Bustamante
Funding: 1.- Estación Biológica de Doñana del Consejo Superior de Investigaciones Científicas (EBD-CSIC). 
2.- Organismo Autónomo de Parques Nacionales (OAPN).
3.- Infraestructuras Científicas y Técnicas Singulares del Ministerio de Ciencia e Innovación (ICTS-MICINN).
4.- Consejería de Agricultura, Ganadería, Pesca y Desarrollo Sostenible de la Junta de Andalucía (CAGPDES-JA). 
5.- European Union.
6.- Ministerio de Ciencia e Innovación (MICINN).
Study area descriptions/descriptor: The study area covers the Natural and National park of Doñana, including the Doñana’s Biological Reserve (RBD).
Design description: The Natural Processes Monitoring Program in Doñana belong to ICTS-RBD. It was created in the 1980s. Initially it focused on birds and endangered species such as the Iberian Lynx or the Imperial Eagle. In 2003, it was extended as part of an extensive monitoring program that included other components of biodiversity and ecological processes (marsh flooding or amphibian and reptile communities). As a summary, data analysis and evaluation are made to take management decisions in a short period of time to minimize the impact of the local and global change. The results are reported annually to the National Park Office and regional authorities through annual reports.

Data published through GBIF: https://ipt.gbif.es/resource?r=icts-rbd_tesgra_20230704

Taxonomic coverage

General taxonomic coverage description: Each tortoise track is associated to Testudo graeca individuals.
Taxonomic ranks
Species: Testudo graeca
Common names: Mediterranean Spur-Thighed Tortoise

Spatial coverage

General spatial coverage: 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.
Coordinates: 90°0'0''S and 90°0'0''N Latitude; 68°0'0''W and 180°0'0''E Longitude 

Temporal coverage: April 1, 2005 - March 14, 2023

Methods

Method step description: The transects (n=10) are distributed within the whole study area (see decimal coordinates of the starting and end of the survey in the dataset as “verbatimCoordinate”) and runs along linear sand trails (n=8) across mediterranean vegetation and throughout circular dunes transects (n=2). Transects have different length ranged between 2-10 kms. The length of the transect is established since the beginning of the study, however it may be variable when a section of the trails is inaccessible because of flooding or when it overlaps with the breeding area of a protected bird species. In these cases, alternative sections of the trail are established to complete the survey.  In total, approximately 60 kms are sampled in Doñana Natural Area. 

Surveys are designed to be performed every two years, however we include data for every year only for dunes transects since these transects overlap with those corresponding to annual surveys of lizards and geckos in dunes, which are included in the same monitoring program of natural resources and processes in Doñana. The transects are conducted by members of the monitoring team usually three times by year in spring or two times in spring (March-May) and once in autumn (October), when the active period of the species is optimal. The census is performed from the front part of the car, at 5-8 km/h, which permits a correct identification of the tortoise tracks.  However, the transects in dunes are always performed on foot, as there are not car trails. In most censuses performed in 2021 the car was not available and were conducted on foot.  The minimum length interval between census is 7 days. At least two days of good weather conditions are needed to perform the surveys (days without rain, strong wind and without night frost) to ensure the activity of the tortoises.

Data recorded during the surveys include the number of individual tortoise tracks observed, life stage when a correct identification is possible (adult or juvenile), sex (recorded when the individual is observed during the survey too), as well as length transect, time and georeferenced data of the observation. Other information as weather description: sky conditions, temperature, precipitation and wind conditions. Wind speed is registered according to Beafourt scale where 0: 0-1 km/h, 1: 1-5 km/h, 2: 6-11 km/h, 3: 12-19 km/h, 4: 20-28 km/h, 5: 29 a 38 km/h.

Between 2005-2007 data were registered in paper and transfer directly in an Excel file. During this period only the number of the tortoise tracks were recorded but not geographic coordinates information of each track could be taken. Since 2008 data are recorded with the app CyberTracker (see protocol) which allows that all geographic coordinates of the tortoise tracks are recorded.  The protocol used has been supervised by herpetological researchers and the data have been validated by the coordinators who have also performed the transects.
Study extent description: The study area for the long-term monitoring of the Mediterranean Spur-Thighed Tortoise (Testudo graeca) is located in southwest Spain in the Guadalquivir Basin and cover the National Park with 542,51 km. The climate is Mediterranean sub-humid with Atlantic coast influence: wet mild winters and dry warm summers. The rainy period occurs between October and April, with a peak in December–January (yearly average precipitation is about 550 mm). Four main ecosystems are described in the area: the marsh, mobile dunes, Mediterranean shrubland with pine forests and a long beach of 30 kms. 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.
Sampling description: One of the aims of this project was to obtain a temporal and continuous series of data of the distribution and abundance of this species to detect changes and trends in the population within the protected area. 
The tortoise population of Doñana has been monitored since 1973 for other research studies (Andreu, A.C., 2000; Díaz-Paniagua, C. et al., 2001). The method used to monitor long-term changes throughout time is the transect survey looking for tortoise tracks, which can be easily detected in the sandy substrates up to 3 days if there are good weather conditions (moderate temperatures, absence of rains or strong wind).
Quality control description: The protocol used has been supervised by herpetological researchers and the data have been validated by the coordinators who have also performed the transects.

Datasets

Dataset description
Object name: Darwin Core Archive Long-term monitoring of the distribution and relative abundance of the Mediterranean Spur-Thighed Tortoise (Testudo graeca) in Doñana 2005-2023
Character encoding: UTF-8
Format name: Darwin Core Archive format
Format version: 1.0
Distribution: https://ipt.gbif.es/archive.do?r=icts-rbd_tesgra_20230704
Publication date of data: 2023-08-17
Language: English
Licences of use: Creative Commons Attribution (CC-BY 4.0) License

Metadata language: English
Date of metadata creation: 2023-07-07
Hierarchy level: Dataset

References
Díaz-Paniagua, C., Claudia Keller and Ana C. Andreu. 2001. Long-term demographic fluctuations of the spur-thighed tortoise Testudo graeca in SW Spain. Ecography 24: 707-721. Copenhagen 2001.  10.1111/j.1600-0587.2001.tb00532.x
Andreu, A. C., C. Díaz-Paniagua y C. Keller. 2000. La tortuga mora (Testudo graeca L.) en Doñana. Edita: Asociación Herpetológica Española. Barcelona. Monografías de Herpetología, Vol. 5: 70 pp.