One of the keys to Doñana exceptional biodiversity is the high diversity of habitats. These habitats are largely determined by the dominant vegetation, to the point of being defined by it in EU's environmental legislation - notably, the Habitats Directive.
Doñana's Biodiversity Monitoring Program estimates regularly the distribution, extent and conservation status of the main habitat units present in Doñana, using a combination of large-scale remote sensing data (Landsat data series, available since 1975) and detailed remote-sensing data (multi- and hyper-spectral images taken from drones) validated with ground-truthing data collected each year at permanent plots. These include:
1. Forest and shrub cover: Changes in the cover of the main types of forest and shrub vegetation present in the Doñana National Park are monitored at 5-year intervals. This information is derived from a supervised classification of Landsat images, validated with ground-truthing data taken at permanent plots (see protocol). In situ information collected at permanent plots includes:
1.1. Juniper forests: Juniper forests are monitored at three 1 ha plots, established in 2005 and monitored on yearly basis using a combination of detailed, remote sensing images (multi-spectral cameras transported on drones) validated with ground-truthing data obtained in three 10x10 m quadrats per 1-ha plot. Each year, all juvenile and adult individuals are measured (height, canopy width and length, leaf damage and flowering intensity), and the number of seedlings and saplings is registered. After validation using ground-truth data, remote sensing images are used to calculate the size structure of the Juniper population for the whole 1-ha plot. See protocol and summary data. Request raw data.
1.2. Pine-juniper forest: Mixed pine-juniper forests were also monitored at 11 10x10 m quadrats situated at Marismillas (see map). Plots were monitored on yearly basis from 2006 to 2012, as in Juniper forest plots. Following an intense perturbation caused by forestry works in 2010, the monitoring of these plots was discontinued. See protocol and summary data. Request raw data.
1.3. Shrubland: Shrubland vegetation is monitored in 21 permanent plots (11 in dry, 4 in intermediate and 6 in wet shrubland) of 15x15 m. Within each plot, the cover of each shrub species is measured in 3 three 10-m transects. These measurements provide estimates of cover and number of individuals per species, proportion of bare soil, species richness and biological diversity per plot. See protocol and summary data. Request raw data.
1.4. Gallery forest: The gallery forest of La Rocina Stream is monitored in 10 circular plots (15-m diameter), where the cover and density of each shrub and tree species is registered. See protocol and summary data. Request raw data.
2. Cork oak forests and heronry: Cork oak forests represent a major conservation concern at Doñana - where they are a keystone species, providing key food resources and nesting substrate to many animal species, most notable Doñana's infamous tree heronry ("pajarera"). In the sandy substrates of the National and Natural Park, cork oaks are typically associated to areas of groundwater discharge - where the water table approaches the surface and falls within the reach of the cork oak's roots. However, recruitment rates have been low for decades and the aging trees that remain are subjected to increasing mortality. The oak-tree monitoring program currently includes a yearly survey of tree occupation (by large nesting birds), survival, health (using a defoliation index) and reproductive yield (acorn production and subsequent predation) of 126 adult trees present in or nearby the Doñana heronry. It also includes biannual measurements of tree dendrometry, i.e. the DBH, height and horizontal canopy size (length and width). See protocol and summary data. Request raw data.
3. Marshland: The vegetation of the Doñana marsh is monitored at 5-years intervals. The monitoring protocol combines the available cartographic information with thematic maps derived from a supervised classification of Landsat images. See protocol and summary data. Request raw data.