Water

This thematic program focuses on the status, dynamics and health of the aquatic ecosystems of the Doñana Protected Areas. These include inflowing rivers, channels and streams; permanent and temporary lakes; as well as floodplain, brackish and salt marshes.

It comprises the following monitoring topics:

1. Hydrodynamics: The Doñana PA host a broad diversity of aquatic ecosystems, which differ broadly in their characteristics and seasonality. Moreover, most inflows and outflows are ungauged. Monitoring their basic hydrodynamic requires an extensive effort, aimed at providing basic data from representative sites of all these ecosystems. These include:

1.1. Water depth: Water depth has been monitored in the Doñana marsh, since 1995, by means of monthly manual readings of up to 45 scales. These measurements were complemented in 2005 with 6 automatic stations that register water depth and salinity at 10-minutes intervals. This monitoring network will be expanded in 2017 to include daily readings at 5 sandy, temporary lakes. See protocol and summary data. Request raw data.

1.2. Inflow and outflow to the marsh: These measurements include most of the major inflow streams/channels and one of the main outflow channel of the Doñana marsh. Inflow measurements are taken at two automatic stations run by ICTS-RBD (Caño Travieso). Outflow measurements include the readings of one automatic station run by ICTS-RBD (Caño de Brenes). These measurements are complemented by the readings of three automatic stations managed by the Guadalquivir River Authority (Arroyo Madre de las Marismas, Azud de la Matanza, Arroyo del Partido). See protocol and summary data. Request raw data.

1.3. Flooding area and hydroperiod in the marsh: Remote-sensing estimates of the flooding area and hydroperiod across the Doñana marshes are produced on regular basis (at least once a year) through a cooperation of ICTS-RBD and LAST-EBD. These estimates are based on Landsat images, available since 1974, and they are informed by a Digital Elevation Model based on a detailed LIDAR data taken in 2002 for the complete surface of the Doñana marsh. See protocol and summary data. Request raw data.

2. Hydrogeology: The groundwater monitoring network of the Almonte-Marismas aquifer, coordinated by the Guadalquivir River Authority, includes 195 measurement points. This network is complemented by additional measurement devices, integrated in ICTS-RBD but maintained and monitored by the Spanish Geological and Mining Institute (IGME). These include: piezometers, soil humidity sensors, a meteorological station and a lysimeter.

3. Water quality: Water quality monitoring currently combines monthly measurements at the 12 localities where water depth is registered continuously (6 in sandy lakes and 6 in the marsh), with extensive winter and spring at the sites where aquatic biota is monitored (ca. 30 localities, see below). In both cases, measurements include the following variables: conductivity, pH, oxygen concentration, turbidity, seston, chlorophyll concentration, and nutrients (ortoP, nitrate, nitrite, ammonia, total P and total N). See protocol and summary data. Request raw data.

4. Aquatic biota: To encompass the broad environmental and biological diversity of Doñana’s aquatic ecosystems, the monitoring program uses a combination of taxon-specific surveys. These surveys coincide at least once a year both temporally (in spring, coinciding with maximum abundance and diversity levels for most taxa) and spatially (ca. 20 sites are sampled for all taxa). However, each survey includes additional localities and/or survey events, to match the specific requirements of each taxon. These include:

4.1. Aquatic plants: Aquatic plants are surveyed once a year, at the time of peak vegetative development and coinciding with flowering/fruiting (mid/late spring). Currently, the survey comprises 10 sampling sites in the marsh, 15 in sandy lakes/ponds, and 1 in an inflowing stream. Measurements include large-scale estimates of total cover of emergent, floating and submerged vegetation; and plot-based estimates of cover per species. See protocol and summary data. Request raw data.

4.2. Amphibians: Amphibians are surveyed twice a year, to cover the period of peak abundance of early (late winter/early spring) and late (mid/late spring) species. Currently, the sampling survey comprises 7 sampling sites in the marsh, 16 in sandy lakes/ponds, and 1 in an inflowing stream. Amphibians are captured using a combination of daytime netting with a standard dip net (number of dip net sweeps proportional to the surface area of each pond) and overnight trapping with collapsible nylon traps (crayfish traps), identified and immediately released. Observations are used to estimate site occupancy and local abundance per species. See protocol and summary data. Request raw data.

4.3. Fish and macroinvertebrates: Fish and macroinvertebrates are surveyed twice a year, to obtain estimates of peak abundance stages (mid/late spring) and population persistence during the main yearly bottleneck (late summer, when flooding is at its minimum). Currently, these surveys comprise: 12 sampling sites in the marsh, 9 in sandy lakes/ponds, and 2 in inflowing streams/channels in spring; and 12 sampling sites in the marsh, 6 in sandy lakes/ponds, and 2 in an inflowing streams/channels in late summer. Fish and macroinvertebrates are captured with collapsible nylon traps (crayfish traps), identified (to species in fish, to coarser taxonomic groups in macroinvertebrates) and immediately released. Observations are used to estimate site occupancy and local abundance per fish species or macroinvertebrate taxon. See protocols (fish, macroinvertebrates in inflowing streams, aquatic macroinvertebrates) and summary data. Request raw data.

4.4. Invasive species: Biological invasions are particularly problematic at Doñana’s aquatic ecosystems. The surveys described above are used also to monitor the spread and abundance of alien species in the Doñana wetlands – including the aquatic fern Azolla filiculoides, the American crayfish (Procambarus clarkii), and several fish like the gambusia (Gambusia holbrooki), carp (Cyprinus carpius), goldfish (Carassius auratus), mummichog (Fundulus heteroclitus), black-bass (Micropterus salmoides), black bullhead (Ameiurus melas) and pumpkin fish (Lepomis gibbosus). See summary data. Request raw data.