Over 30 years after drainage for agriculture, a 2700 ha temporary marshland was recently restored in Doñana National Park. We describe the recovery of zooplankton communities (copepods, cladocerans and rotifers) in 47 new temporary ponds excavated as part of the restoration project during the first two hydroperiods (April 2006 and, and compare them to those of eight reference sites in the surrounding marshland. Major changes in the species composition and abundance occurred in new ponds between years. While rotifers and cyclopoid copepods dominated in terms of number of individuals in 2006, calanoid copepods and cladocerans were the most abundant groups in 2007. Rotifer species richness was significantly lower in 2007, but there was an increase in Simpson and b-diversity in 2007 owing largely to a dramatic decline in the abundance of Hexarthra cf. fennica (rare in reference sites) from 93% of all rotifer individuals in new ponds in 2006 to only 32% in 2007. In contrast, species richness of copepods and cladocerans was significantly higher in new ponds in 2007, but there were no changes in Simpson diversity. b-Diversity of cladocerans was also significantly higher in 2007. In 2006, the species richness of cladocera and copepods was significantly lower in new ponds than in reference sites, but by 2007 there were no differences in richness or Simpson diversity. Overall, 7 copepod, 13 cladoceran and 26 rotifer taxa were recorded in new ponds, including 80% of taxa recorded in reference sites. These results indicate that zooplankton communities can be rapidly restored in Mediterranean temporary wetlands, at least when large source populations in the surrounding area reduce dispersal limitation. They also illustrate the importance of comparing different metrics of richness and diversity in studies of zooplankton restoration.

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The viable propagule banks of a temporary stream were studied from sections with different agricultural history. Hatching of zooplankton (copepods, rotifers and cladocerans) was recorded in the laboratory under controlled temperature and light conditions from an agriculturally modified area with average hydroperiods of about a week per year and two semi-natural reference areas with average hydroperiods of more than 3 weeks per year. We found significant differences in both taxon richness and abundance of zooplankton hatching between areas, which were lower in the agriculturally modified section, compared to the reference sections. Another factor likely to have influenced hatching in our experiment was conductivity, which differed between the two reference sections and might have affected hatching at high conductivities. For restoration purposes, hydrological reconnection of stream segments is important to facilitate dispersal from the high diversity upstream segments to the depleted sites downstream.

The Doñana Natural Area includes a large array of wetlands with the highest degree of environmental protection in Spain, and so it has long attracted many studies. We present a cumulative list of zooplankton taxa (Copepods and Branchiopods) based on a collection of 18 publications and 4 unpublished studies. Seventy-eight taxa have been recorded in a set of 55 ponds, and 72 taxa at 38 sites spread over the Doñana marshland. In total, 96 taxa have been recorded, including 50% of all branchiopod species reported for the whole Iberian Peninsula. Taxa composition was significantly segregated between ponds and marshland during floods (ANOSIM test, R = 0.929, P \ 0.01), but this segregation disappeared at a larger spatio-temporal scale when a nonmetric MDS ordination produced a gradient from ponds to marshland (ANOSIM test, R = 0.272, P \ 0.01). The lack of segregation between ponds and marshland sites, and among ponds with different hydroperiods, was not due to a large number of cosmopolitan species, but to a random distribution of a large number of low-occurrence species (67% of total taxa occurred with a frequency \15%). Long-hydroperiod ponds occupy a key position among the Doñana wetlands in terms of biodiversity as these ponds accumulated a high crustacean richness over time. They also supported a significantly higher cumulative number of cladoceran and harpacticoid taxa, while short-hydroperiod ponds accumulated the lowest number of diaptomid taxa. Our data indicate the need for recording biodiversity in the long term as richness on a short-temporal scale is not a good indicator of the number of crustacean species that would be encountered with a longer sampling period in Mediterranean temporary wetlands.

Phytoplankton from NE Do ñana marshland ("El Cangrejo Grande", Do ñana Natural Park, Spain)The study area ("El Cangrejo Grande", Doñana Natural Park) is located at the final section of the Guadiamar River channel and it is a part of the NE Doñana marshland. The hydrological characteristics of the area are complex and dynamic due to the different origin of its water input: the Guadiamar River basin, the Guadalquivir River estuary, and rice paddies outlets. This area is included in the hydrologic regeneration plan for the Doñana marshland ("Doñana 2005"), though the present study was finished before any modification took place. Phytoplankton richness was high since a total of 224 phytoplankton taxa were registered. Diatoms and Clorophytes were the groups that had the highest richness, Nitzschia palea, Cyclotella atomus and Monoraphidium contortum being the most widely distributed and abundant species. Phytoplankton exhibited a strong seasonal variation, in both composition and biomass, segregated in two periods (flood and desiccation) as suggested by the results of the PCA. On the other hand, the spatial differences were less evident according to a multidimensional scaling analysis (MDS). This seasonal pattern was stronger in the ordination of physico-chemical variables (conductivity, nutrient concentration and suspended matter). We conclude that this system is an ecotone zone with a high hydrologic complexity due to a variety of water inputs with a strong seasonality. These hydrologic features would be the determining factor in phytoplankton composition and high taxon richness.