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Doņana National Park (doņana + national_park)
Selected AbstractsDiversity, distinctiveness and conservation status of the Mediterranean coastal dung beetle assemblage in the Regional Natural Park of the Camargue (France)DIVERSITY AND DISTRIBUTIONS, Issue 6 2001Jorge Miguel Lobo Abstract. The Mediterranean region as a whole has the highest dung beetle species richness within Europe. Natural coastal habitats in this region are among those which have suffered severe human disturbance. We studied dung beetle diversity and distinctiveness within one of the most important coastal protected areas in the west Euro-Mediterranean region (the regional Park of Camargue, southern France) and made comparisons of dung beetle assemblages with other nearby Mediterranean localities, as well as with other coastal protected area (Doņana National Park, Spain). Our finding showed that: (1) The species richness of coastal habitats in the Camargue is low and only grasslands showed a similar level of species richness and abundance to inland habitats of other Mediterranean localities. The unique habitats of the coastal area (beaches, dunes and marshes) are largely colonized by species widely distributed in the hinterland. (2) In spite of their low general distinctiveness, dune and marsh edges are characterized by the occurrence of two rare, vulnerable, specialized and large roller dung beetle species of the genus Scarabaeus. As with other Mediterranean localities, current findings suggest a recent decline of Scarabaeus populations and the general loss of coastal dung beetle communities in Camargue. (3) The comparison of dung beetle assemblages between the Camargue and Doņana shows that, in spite of the low local dung beetle species richness in the Camargue, the regional dung beetle diversity is similar between both protected areas. Unique historical and geographical factors can explain the convergence in regional diversity as well as the striking divergence in the composition of dung beetle assemblages between both territories. [source] The regulation of brood reduction in Booted Eagles Hieraaetus pennatus through habitat heterogeneityIBIS, Issue 4 2008EVA CASADO Brood reduction, the death of one or more chicks through siblicide or starvation, can occur through density-dependence in fecundity. Brood reduction may arise in territorial breeding systems either as a response to a high level of territorial interference in a situation of high density or as a result of habitat heterogeneity. To test the predictions of the two main hypotheses that attempt to explain how density-dependent fecundity is generated, the Habitat Heterogeneity Hypothesis (HHH) and the Individual Adjustment Hypothesis (IAH), we analysed the relationship between density and fecundity in an expanding population of Booted Eagles in Doņana National Park, Spain, using an 18-year data series. We also studied the occurrence and frequency of brood reduction in the same Booted Eagle population to appreciate further its effects and the factors that influence its occurrence and frequency. Our results support the HHH in the present situation of high density, as fecundity in the better territories (older and more frequently occupied) was higher than in low quality territories and was not affected by population density in high density periods. Nevertheless, the fecundity of high quality territories was affected (although not significantly) by population density in periods of low density, suggesting that the IAH was supported when only high quality territories were occupied. Older territories were used more frequently and chicks in these areas hatched earlier and suffered lower mortality than in new territories. We found a significant negative relationship between mean fecundity and its skewness, a finding that also supports HHH. During years of food shortage, less frequently occupied territories suffered higher rates of brood reduction. Brood reduction in this Booted Eagle population was a consequence of the heterogeneous structure of the habitat, with some territories having a higher probability of brood reduction than others. Parental nutritional condition did not affect brood reduction. The effect of brood reduction on nestling quality and population dynamics is also discussed. [source] Non-independence of demographic parameters: positive density-dependent fecundity in eaglesJOURNAL OF APPLIED ECOLOGY, Issue 5 2008Miguel Ferrer Summary 1Using information on the Doņana population of Spanish imperial eagles Aquila adalberti from 1959 to 2004, we present strong empirical support to theoretical models on the regulation of population trajectories by the relationships between breeder mortality and floater availability. 2During the study period, the eagle population showed three distinct phases: (i) a population increase with negative density-dependent fecundity; (ii) a period of stability without any relationship between density and fecundity; and (iii) a population decrease with a positive relationship between density and fecundity. 3A dramatic increase in annual adult mortality due to an increase in poisoning in hunting areas surrounding the Doņana National Park was recorded. The use of poison against generalist predators accounted for more than 54% of the total number of breeding eagles found dead since 1990, increasing annual adult mortality from 6ˇ07 to 12ˇ01%. 4This high mortality reduced the population annually by 6% during the 1992,2004 period. Also, the population changed from a negative to a positive relationship between density and fecundity (Allee effect). These trends made the population approach extinction due to the double effect of increasing breeder mortality and low availability of floaters. 5A supplementary feeding programme established in 1990 did not increase fecundity because it was a consequence of high adult mortality rather than low food availability. The high mortality of adults increased the risk of breeding failure and also decreased the availability of floaters, decreasing the likelihood of mate substitution. 6Synthesis and applications. The main target in species conservation management plans is often a single demographic parameter (typically, fecundity in raptor populations). Our research demonstrates, however, that demographic parameters must not be considered as independent variables when formulating management programmes. The essential relationship between adult mortality and the availability of floaters must be better understood to avoid the risk of implementing inefficient management strategies. Although fecundity was low in this eagle population, it was a result of high adult mortality rates. Consequently, management must aim to correct the unusual mortality and recover the floater population. [source] Sample size and the detection of a hump-shaped relationship between biomass and species richness in Mediterranean wetlandsJOURNAL OF VEGETATION SCIENCE, Issue 2 2006J.L. Espinar Abstract Questions: What is the observed relationship between biomass and species richness across both spatial and temporal scales in communities of submerged annual macrophytes? Does the number of plots sampled affect detection of hump-shaped pattern? Location: Doņana National Park, southwestern Spain. Methods: A total of 102 plots were sampled during four hydrological cycles. In each hydrological cycle, the plots were distributed randomly along an environmental flooding gradient in three contrasted microhabitats located in the transition zone just below the upper marsh. In each plot (0.5 m × 0.5 m), plant density and above- and below-ground biomass of submerged vegetation were measured. The hump-shaped model was tested by using a generalized linear model (GLM). A bootstrap procedure was used to test the effect of the number of plots on the ability to detect hump-shaped patterns. Result: The area exhibited low species density with a range of 1,9 species and low values of biomass with a range of 0.2 -87.6 g-DW/0.25 m2. When data from all years and all microhabitats were combined, the relationships between biomass and species richness showed a hump-shaped pattern. The number of plots was large enough to allow detection of the hump-shaped pattern across microhabitats but it was too small to confirm the hump-shaped pattern within each individual microhabitat. Conclusion: This study provides evidence of hump-shaped patterns across microhabitats when GLM analysis is used. In communities of submerged annual macrophytes in Mediterranean wetlands, the highest species density occurs in intermediate values of biomass. The bootstrap procedure indicates that the number of plots affects the detection of hump-shaped patterns. [source] Recovering the Reptile Community after the Mine-Tailing Accident of Aznalcķllar (Southwestern Spain)RESTORATION ECOLOGY, Issue 5 2009Rocío Márquez-Ferrando Abstract Ecosystem restoration requires that habitat requirements of all species be considered. Among animal communities in Mediterranean ecosystems, reptiles, as ectothermic vertebrates, need refuges for avoidance of extreme environmental temperatures, concealment from predators, and oviposition sites. In 1998, a massive amount of tailings broke out of the holding pond of the Aznalcķllar mine (southwestern Spain) and polluted the Guadiamar river valley. After the accident, a soil- and vegetation restoration program began, and the Guadiamar Green Corridor was created to connect two huge natural areas, Doņana National Park and the Sierra Morena. Within this corridor, the reptile community remained dramatically impoverished, probably because of elimination of all natural refuges during the soil restoration program. To test this hypothesis, we set an array of artificial refuges (logs) in a large experimental plot. During the 5 years of the experiment (2002,2006), the area managed with artificial refuges exhibited a better and faster recovery of the reptile community in species richness and individual abundance than did the control area with no artificial refuges. Moreover, reptile colonization of the Guadiamar Green Corridor was transverse rather than lineal,that is, it did not act as a corridor for reptiles, at least in the first stages of colonization. This suggests that landscape restoration programs should not neglect refuge availability, a limiting resource for reptile species. [source] Inter-annual variability in amphibian assemblages: implications for diversity assessment and conservationAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 6 2010Carola Gķmez-Rodríguez Abstract 1.Diversity assessments and conservation management should take into account the dynamic nature of populations and communities, particularly when they are subject to highly variable and unpredictable environmental conditions. 2.This study evaluates the inter-annual variability in the assemblage composition (temporal turnover) of an amphibian community breeding in a highly dynamic habitat, a Mediterranean temporary pond system, during a 4-year period. 3.A comprehensive framework is provided to evaluate temporal turnover from data of a differing nature (species richness, presence/absence and relative abundance) and, especially, to discern variation in richness (species loss) from changes in the identity or abundance of species (species replacement). 4.Results show that the pond amphibian assemblages in Doņana National Park exhibited high inter-annual variability during the study period, both in the number of species, species identity and their relative abundance. This result provides evidence for the inadequacy of surveys conducted only in one breeding season to characterize the species assemblage associated with a given pond. Besides, it suggests that a given pond offers different breeding opportunities over time, being suitable for different species depending on the year. This alternation will contribute to the medium-term preservation of all species in the assemblage. 5.It is highly relevant to preserve the natural dynamism and spatial variability of temporary pond systems, which will favour the conservation of populations through their intrinsic variability. Copyright Š 2010 John Wiley & Sons, Ltd. [source] Complementary use of natural and artificial wetlands by waterbirds wintering in Doņana, south-west SpainAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 7 2009Janusz Kloskowski Abstract 1.The Doņana wetland complex (SW Spain) holds more wintering waterfowl than any other wetland in Europe. 2.This study focused on the use made by 12 common waterbirds (eight ducks and four waders) of the natural seasonal marshes in Doņana National Park (DNP) and the adjacent Veta la Palma (VLP) fish ponds created in the early 1990s. Data used were from aerial and terrestrial surveys collected between October and February during six consecutive winters from 1998/99 to 2003/04. Changes in distribution of each bird taxon were related to changes in the extent of flooded marshes within DNP. Up to 295,000 ducks were counted in VLP during dry periods, and up to 770,000 in DNP when it was flooded. 3.The timing and extent of flooding in DNP was highly variable, but there was a consistent pattern in which ducks concentrated in VLP during dry months and winters but redistributed to DNP as more of it was flooded. This refuge effect was also strong for black-tailed godwits Limosa limosa, but much less so for other waders. Waders feed mainly on invertebrates, and invertebrate biomass in VLP was found to be higher than in DNP. Ducks feed mainly on seeds and plant material, which are more abundant in DNP when flooded. 4.When water levels in DNP were stable over the course of a winter, or controlled for in multivariate models, the numbers of ducks at VLP declined over time, probably due to reduced availability of plant foods. In contrast, numbers of waders at VLP were more stable, and their invertebrate prey became more abundant over time, at least in the winter 2003/4. 5.In this extremely important wetland complex, the value of natural and artificial wetlands for wintering waterbirds are complementary, providing suitable habitat for different species and for different conditions in a highly variable Mediterranean environment. Copyright Š 2009 John Wiley & Sons, Ltd. [source] The relevance of preserving temporary ponds during drought: hydrological and vegetation changes over a 16-year period in the Doņana National Park (south-west Spain)AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 3 2008Laura Serrano Abstract 1.Although the Doņana National Park is given the highest degree of environmental protection in Spain, it is likely that groundwater discharge to several ponds within the Biological Reserve has been damaged by abstraction to a tourist resort located less than 1 km away. 2.Hydrological changes were monitored over 16 years (1 October 1989 to 30 September 2005) by recording the shallow water table of six temporary ponds at 1,8-week intervals, and the duration of pond wet phase (or hydroperiod) during each hydrological cycle. 3.The average rainfall for the study period was 563.2 mm, and included 6 wet, 5 moderate, and 5 dry years in a seemingly random sequence. The average rainy season extended from October until the end of March, while the dry season occupied the rest of the year. 4.The water table generally oscillated following this alternation of rainy and dry seasons, but this fluctuation was minimal during dry years, and even failed to occur at some ponds. 5.Since 1998/99, the average hydroperiod has shortened by 3 months at Charco del Toro pond, and by almost 2 months at Brezo pond, while the rest of the ponds exhibited a reduction of less than 1 month. 6.Vegetation changed in the ponds between May 1990 and 2005. Total plant cover increased (range of increase: 16,65%), and species richness decreased in all ponds (range of species loss: 4,18). 7.The reduction in the hydroperiod probably enhanced the growth of a few woody plants to the detriment of flooding-dependent species as the cover of Pinus pinea increased nearly fourfold at Brezo pond, while that of Scirpus lacustris was halved at Charco del Toro pond. 8.The pumping area for the nearby tourist resort should be relocated, and a specific management strategy should be developed in order to prevent further damage to the ponds. Copyright Š 2007 John Wiley & Sons, Ltd. [source] The effect of the sampling scale on zooplankton community assessment and its implications for the conservation of temporary ponds in south-west SpainAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 2 2007Khalid Fahd Abstract 1.The zooplankton (rotifer and microcrustacean) assemblages of temporary ponds in the Doņana National Park (south-west Spain) have been compared in two surveys of contrasting scales that resulted in the same number of samples: an extensive survey of 36 ponds sampled in May 1998 (or widespread survey) and a survey of nine ponds sampled four times over 2 years (or cumulative survey). 2.The total number of microcrustacean and rotifer taxa was larger in the cumulative survey (43 and 41 taxa, respectively) than in the widespread survey (39 and 34, respectively). Crustacean assemblages became less alike throughout the cumulative survey. 3.The presence of invertebrates (Coleoptera, Odonata, Heteroptera and crayfish) and aquatic vertebrates (fish and salamanders) was recorded as an estimate of potential predator impact on zooplankton. Several pond features (water depth, conductivity, pH, chlorophyll a concentration, distance to the nearest permanent pond and to the marsh) were also measured in both surveys. 4.A combination of these environmental factors was more strongly related to the similarity matrices derived from the zooplankton assemblages of the cumulative survey (Rho=0.7) than to those of the widespread survey (Rho<0.4). The distance of ponds to the marsh was an important factor in explaining this correlation as well as the strongest factor in the ordination of crustacean assemblages following a CCA. 5.Predation by exotic fish in long-hydroperiod ponds where overflow drains to the nearby marsh (fish source) is the mechanism likely to explain the changes in crustacean composition recorded in the cumulative survey. 6.The cumulative survey was more suitable for the study of zooplankton diversity as it rendered a higher number of taxa and gave more insight into the mechanisms that explain taxon richness. Thus, conservation strategies in temporary habitats require a scale of observation that includes long temporal changes. Copyright Š 2006 John Wiley & Sons, Ltd. [source] | ||||||||||