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El Sistema de Lagunas Temporales de Doñana, una red de hábitats acuáticos singulares.

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... We collected sediment from a temporary pond in Doñana National Park, which is located in southwestern Spain (36°59 0 10 00 N, 6°29 0 21 00 W). This area contains a pond network with a large number and high density of Mediterranean temporary ponds that are located on sandy soil and usually dry out during the summer (Díaz-Paniagua et al., 2015). Every year, a new inundation cycle starts when post-summer rains accumulate and recharge the aquifer, producing a rise in groundwater level for the pond basins. ...
... Every year, a new inundation cycle starts when post-summer rains accumulate and recharge the aquifer, producing a rise in groundwater level for the pond basins. The temporary pond that we selected had a sandy bottom, a maximum depth of 70 cm, and an intermediate hydroperiod (relative to the known hydroperiod range in the study area [Díaz-Paniagua et al., 2015]). We chose a pond with an intermediate hydroperiod because it provided a better representation of the study area. ...
... These threats include the drawdown of groundwater levels due to the overexploitation of the aquifer (Manzano & Custodio, 2006;Custodio et al., 2009), which may be exacerbated by the increased temperatures and altered precipitation regimes associated with climate change (Green et al., 2017). Such factors increase the amount of rain needed to fill the ponds, which can delay pond filling and reduce the length of the wet phase (Díaz-Paniagua et al., 2015), thereby impoverishing the ponds' zooplankton assemblages. The indicator species that we observed in the autumn and winter treatments may be the first to disappear if both the phenomena cited above occur for several years in a row. ...
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In Mediterranean temporary ponds, the timing of annual flooding is highly variable and depends on heavy seasonal rains. Ponds can flood in the autumn, winter, or spring, and thus the environmental conditions faced by emerging zooplankton can be very different. We performed an experiment in a climatic chamber where we simulated annual variation in natural temperature and light conditions to study how differences in pond-filling season affected zooplankton assemblage composition. We sampled sediments from a temporary pond and placed them in aquariums that were filled with water during three different seasons: autumn (October), winter (January), and spring (March). Zooplankton abundance, species richness, diversity, and assemblage composition differed significantly among treatments, and post-inundation temperature and pH appeared to be the main drivers of these differences. Diversity was highest in the winter treatment. It was lower in the autumn treatment and the spring treatment, and no indicator species were present in the latter. Our results suggest that interannual variability in initial inundation conditions favours the emergence of different species and thus contributes to high species richness in the egg bank. However, climate change and/or groundwater drawdown could delay pond flooding, impoverishing the zooplankton assemblage in the long term.
... In Mediterranean ecosystems, the timing and quantity of precipitation can be highly unpredictable. It is common for years of heavy rains, during which ponds display very long hydroperiods (>8 months), to alternate with very dry years, during which ponds are ephemeral or may not even flood [4,5]. In temporary wetlands found in regions with warm, dry summers, aquatic plants cannot re-establish themselves via asexual propagules and mainly depend on seed production and the formation of a persistent seed bank [6][7][8][9][10][11][12][13]. ...
... In other years, which may be drier, ponds flood in the spring and have hydroperiods of 3-5 months. Most ponds dry up in the summer [4,5]. This marked heterogeneity in pond hydroperiod favors high plant diversity (i.e., >200 species; [25,26]). ...
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In temporary ponds, seed germination largely determines how well aquatic plant assemblages recover after dry periods. Some aquatic plants have terrestrial morphotypes that can produce seeds even in dry years. Here, we performed an experiment to compare germination patterns for seeds produced by aquatic and terrestrial morphotypes of Ranunculus peltatus subsp. saniculifolius over the course of five inundation events. During the first inundation event, percent germination was higher for terrestrial morphotype seeds (36.1%) than for aquatic morphotype seeds (6.1%). Seed germination peaked for both groups during the second inundation event (terrestrial morphotype: 47%; aquatic morphotype: 34%). Even after all five events, some viable seeds had not yet germinated (terrestrial morphotype: 0.6%; aquatic morphotype: 5%). We also compared germination patterns for the two morphotypes in Callitriche brutia: the percent germination was higher for terrestrial morphotype seeds (79.5%) than for aquatic morphotype seeds (41.9%). Both aquatic plant species use two complementary strategies to ensure population persistence despite the unpredictable conditions of temporary ponds. First, plants can produce seeds with different dormancy periods that germinate during different inundation periods. Second, plants can produce terrestrial morphotypes, which generate more seeds during dry periods, allowing for re-establishment when conditions are once again favorable.
... Although there have been positive decisions in the way the Park has been managed by the local authorities, such as the decision not to dredge the Guadalquivir River, there are still other resolutions awaiting that may have an influence on the site. DNP has undergone a great deal of change over the course of the twentieth century, but such changes have been abrupt during the past 20 years (Díaz-Paniagua et al. 2015). The great majority of these changes have to do with hydrological impacts due to an unplanned increment in groundwater abstractions in the aquifer for agriculture, such as strawberries (now covering 6000 ha in the eastern area), fruits, cotton, rice, and orchards (Green et al. 2017). ...
... Some of them are located in vegetation-stabilized dunes, so their existence dates back several hundreds of years, whereas others are much more ephemeral and exist only for a few days after rainy episodes. Only a small fraction of the ponds consists of permanent, seasonal or temporary water bodies (Díaz-Paniagua et al. 2015). ...
Article
This paper aims to determine how both climate and local drivers, such as groundwater withdrawals influence surface water - groundwater interactions in Groundwater Dependent Ecosystems (GDEs). We studied the hydroperiod in eight of the most representative ponds of Doñana National Park (southern Spain) during a 21-year period. We analyzed the average flooded phase of each pond as well as the average depth of the piezometric level in nearby piezometers. In addition, we used the average precipitation as a proxy of the water inputs onto the ponds. The average flooded surface was taken by a previous analysis of satellite images and the depth to the piezometric level was field measured at a monthly time step. We found out that the average precipitation was slightly lower during the second decade (675 mm/y vs. 552 mm/y). Nonetheless, 5/8 of the ponds showed a much higher shrinking of the flooded surface that could not be explained only by a reduction in the precipitation events. Local drivers were found to be decisive in the degradation of 3/8 of the ponds: those closer to a pumping facility and located at a higher altitude.
... kyr BP, recurrent episodes of Juniperus, with a probable~200-400 years periodicity following our chronological model, suggest dune development periods. Dune development is promoted under arid, wind-enhanced conditions (Dabrio et al., 1996;Díaz-Paniagua et al., 2015). However, the dune domes, despite being xerophytic enclaves (Muñoz Reinoso, 2001;Muñor-Reinoso and de Castro, 2005;Muñoz-Reinoso and García Novo, 2005) function as recharge areas and extend the Doñana aquifer volume (Manzano et al., 2013). ...
Article
The southern European Doñana wetlands host a highly biodiverse landscape mosaic of complex transitional ecosystems. It is one of the largest protected natural sites in Europe, nowadays endangered by intensive agricultural practices, and more recently tourism and human-induced fires. Its present-day spatial heterogeneity has been deeply investigated for the last three decades. However, a long-term perspective has not been applied systematically to this unique landscape. In this new study, a palaeoecological approach was selected in order to unravel patterns of landscape dynamism comparing dry upland and aquatic ecosystems. A 709 cm-long sediment core was retrieved and a multi-proxy approach applied (palynological, microcharcoal, grain size, magnetic susceptibility, loss-on-ignition and multivariate statistical analyses). Pollen signatures show how sensitive aquatic wetland vegetation was to environmental changes while terrestrial vegetation was stable at millennial scale. The impact of several high energy events punctuates the Early and Middle Holocene sequence, two of which relate to the local tsunami record (~ 6.6 and ~ 9.1 cal. kyr BP). Contrasting impacts of these two events in the aquatic and upland ecosystems show the importance of landscape configuration and the contingent history as key elements for coastal protection.
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In temporary ponds, submerged plants have adapted to recurrent periods of drought. These ponds often lack the impact of large herbivores but can harbor large numbers of herbivorous tadpoles. Tadpoles of the Iberian spadefoot toad (Pelobates cultripes) may reach large body size and consume large quantities of macrophytes during their long larval period, which is shortened with risk of pond drying. We conducted a mesocosm experiment to analyze the interplay between hydroperiod and impact of herbivorous tadpoles on the abundance and life history of 3 species of submerged plants common to temporary ponds. We observed differences in growth among plant species resulting in lags in timing of maximum cover, probably related to interspecific competitive interactions. Some plants responded to pond drying with a remarkable increase in the production of flowers. Tadpoles greatly reduced the plant cover, although their impact varied across plant species. Differential plant consumption by these large tadpoles can substantially modify the internal structure and complexity of temporary ponds, and tadpoles can also interfere with plant responses to shortened hydroperiod.
Article
Time series analysis methods have been used to detect behavioral patterns in a set of nine time series. These series contained information in a 3‐hour time step about meteorological, hydrological and tidal data of a sand dune pond area located in Doñana National Park in the southwest of Spain. The methods used, such as wavelet analysis and additive seasonal decomposition, had never been applied before in the types of ecosystems studied. These approaches have improved the current knowledge of the conceptual model of the Santa Olalla pond system, the only system with a permanent hydroperiod located in this protected area. In addition, complex surface water–groundwater interactions, not visible through descriptive methods, have been distinguished to have a strong seasonal component. Finally, we evaluated the effect of pumping activity in a nearby coastal resort on the water supply of the Santa Olalla pond system. Although direct damage to this sand dune pond has not yet been identified, special attention must be paid in order to maintain groundwater inputs that are integral to maintaining its current status. This article is protected by copyright. All rights reserved.
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Mediterranean seasonal wetlands are amongst the world’s most endangered ecosystems. Although seasonal wetlands’ conservation is a European continental-scale priority, their long-term ecological dynamics are not well known, hampering the detection of baseline conditions. However, a long-term ecological viewpoint could aid in the detection of spatiotemporal factors controlling wetland development. We have applied a multi-proxy palaeoecological approach (palynological, microcharcoal, magnetic susceptibility, loss on ignition and diversity estimates analyses) on a 360-cm core retrieved from the El Sopetón (ElSo), a temporary wetland nested between dunes in the paradigmatic Doñana coastal area. The palaeoecological analyses reveal ~ 300–500-year-long wetland phases linked to dune immobilisation during humid periods. During the first wetland phase (AD ~ 40–315), upland and wetland vegetation diversity dynamics follow opposite trends owing to the different effect that dune proliferation had on them. Fixed dune landscapes provided upland spatial diversification, while they promoted a longer hydro-period in ElSo, simplifying wetland vegetation. During the second wetland phase (AD ~ 1550–2012), land-use change drove environmental dynamics. The mid-eighteenth-century pine afforestation to fix moving dunes marked an environmental tipping point, with the ElSo wetland transitioning from seasonal to permanent. This translated into a rising trend in upland diversity and a decreasing trend in the wetland one. Despite the recent pine afforestation, the palaeoecological findings evidence the autochthonous character of Pinus pinea, as well as the naturalness of the wetland species Hydrocharis morsus-ranae and Ricciocarpos natans. The geomorphological dynamism of the diverse Doñana coastal setting is the baseline for the area, modulating wetland-upland water connectivity and, ultimately, controlling biodiversity trends. The preservation of Doñana natural dynamism and landscape heterogeneity should be considered for the management, conservation and restoration of its seasonal wetlands.
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