Condicionantes ecológicos de la distribución de anfibios en el Parque Nacional de Doñana

[ES] En esta tesis se analizan los requerimientos de hábitat de las especies de anfibios en el Parque Nacional de Doñana, prestando una atención especial a los aspectos metodológicos que pueden sesgar los resultados inferidos. En particular, se ha tenido en cuenta la dinámica temporal del sistema y la fiabilidad de las ausencias, una consecuencia directa de la detectabilidad imperfecta de la especie en el área. También se ha evaluado la utilidad de la teledetección en el estudio de la variación espacial y temporal de los hábitats reproductivos de los anfibios y en la elaboración de modelos estadísticos de distribución de las especies.[EN] In this thesis there are analyzed the requirements of habitat of the species of amphibians in Doñana's National Park, giving a special attention to the methodological aspects that can slant the inferred results. Especially, there has been born in mind the temporary dynamics of the system and the reliability of the absences, a direct consequence of the imperfect detectabilidad of the species in the area. Also the usefulness of the teledetección has been evaluated in the study of the spatial and temporary variation of the reproductive habitats of the amphibians and in the production of statistical models of distribution of the species

Assessing the equilibrium between assemblage composition and climate: A directional distance-decay approach

1. The variation of assemblage composition in space is characterised by the decrease in assemblage similarity with spatial distance. Climatic constraint and dispersal limitation are major drivers of distance-decay of similarity. Distance-decay of similarity is usually conceptualised and modelled as an isotropic pattern, that is, assuming that similarity decays with the same rate in all directions. 2. Because climatic gradients are markedly anisotropic, that is, they have different strength in different directions, if species distributions were in equilibrium with climate, the decay of assemblage similarity should be anisotropic in the same direction as the climatic gradient, that is, faster turnover in the direction that maximises the climatic gradient. Thus, deviations from equilibrium between assemblage composition and climatic conditions would result in differences in anisotropy between distance-decay of similarity and climatic gradients. 3. We assessed anisotropy in distance-decay patterns in marine plankton assemblages, terrestrial vertebrates and European beetles, using two procedures: (a) measuring the correlation between the residuals of a distance-decay model and the angle in which pairs of sites are separated and (b) computing two separate distance-decay models for each dataset, one using only pairwise cases that are separated on North-South direction and another one using pairwise cases separated on East-West direction. We also analysed whether the degree of anisotropy in distance-decay is related to dispersal ability (proportion of wingless species and body size) and ecological niche characteristics (main habitat and trophic position) by assessing these relationships among beetle taxonomic groups (n = 21). 4. Anisotropy varied markedly across realms and biological groups. Despite climatic gradients being steeper in North-South direction than in East-West direction in all datasets, North-South distance-decays tended to be steeper than East-West distance-decays in plankton and most vertebrate assemblages, but flatter in European amphibians and most beetle groups. 5. Anisotropy also markedly varied across beetle groups depending on their dispersal ability, as the proportion of wingless species explained 60% of the variance in the difference between North-South and East-West distance-decay slopesThis research was supported by the Spanish Ministerio de Ciencia, Innovación y Universidades and the European Regional Development Fund (ERDF) through grant CGL2016-76637-PS

Condicionantes ecológicos de la distribución de anfibios en el Parque Nacional de Doñana (2009)

Peer reviewe

Mediterranean temporary ponds as amphibian breeding habitats: The importance of preserving pond networks

We describe the spatial and temporal variation in the main characteristics of amphibian breeding habitats in Doñana National Park (south of Spain), during two hydrologic cycles with different rainfall amounts and timing (2002-2003 and 2005-2006). We also evaluate amphibian habitat requirements following a model selection approach based on Akaike's Information Criterion. Our results evidenced large spatial variability in all pond characteristics and inter-annual differences in pond hydroperiod, depth, and most water-chemistry characteristics. We observed a remarkable independence of pond characteristics at different sampling dates, suggesting that a pond description based on a single survey may not be representative. Eight of nine amphibian species attempted breeding in both years in spite of the marked inter-annual variability. Habitat models were species-specific and year-specific, as we found inter-annual differences in the pond characteristics relevant for species richness or for the relative abundance of particular species. All these results suggest that this large and diverse network of ponds provides different habitat opportunities each year, favouring the long-term persistence of the whole amphibian community. © Springer Science+Business Media B.V. 2009.Peer Reviewe

Rare failures of DNA bar codes to separate morphologically distinct species in a biodiversity survey of Iberian leaf beetles

During a survey of genetic and species diversity patterns of leaf beetle (Coleoptera: Chrysomelidae) assemblages across the Iberian Peninsula we found a broad congruence between morphologically delimited species and variation in the cytochrome oxidase (cox1) gene. However, one species pair each in the genera Longitarsus Berthold and Pachybrachis Chevrolat was inseparable using molecular methods, whereas diagnostic morphological characters (including male or female genitalia) unequivocally separated the named species. Parsimony haplotype networks and maximum likelihood trees built from cox1 showed high genetic structure within each species pair, but no correlation with the morphological types and neither with geographic distributions. This contrasted with all analysed congeneric species, which were recovered as monophyletic. A limited number of specimens were sequenced for the nuclear 18S rRNA gene, which showed no or very limited variation within the species pair and no separation of morphological types. These results suggest that processes of lineage sorting for either group are lagging behind the clear morphological and presumably reproductive separation. In the Iberian chrysomelids, incongruence between DNA-based and morphological delimitations is a rare exception, but the discovery of these species pairs may be useful as an evolutionary model for studying the process of speciation in this ecological and geographical setting. In addition, the study of biodiversity patterns based on DNA requires an evolutionary understanding of these incongruences and their potential causes.AB was funded by the Spanish Ministry of Science and Innovation (grant CGL2009-10111). CGR is funded by the Xunta de Galicia(postdoctoral fellowship POS-A/2012/052)S

Trees as habitat islands: temporal variation in alpha and beta diversity in epiphytic laurel forest bryophyte communities

Aim: Trees represent striking examples of habitat islands, with various degrees of spatial isolation and evolving properties during their life cycle. Here, we investigate whether changes in habitat conditions, dispersal limitations or competition cause variation in patterns of epiphytic species richness and turnover. Location: Madeira island. Taxon: Bryophytes. Methods: Using linear mixed effect models, we test whether species richness exhi bits a monotonic or hump-shaped relationship with time. Two groups of host-tree species, late- and early-successional, were considered. We further identify the mechanisms explaining the observed variation in species composition by dividing beta diversity into its nestedness (bsne) and turnover (bsim) components and correlat ing them with tree age and geographical distance among trees. Results: The best-fit models all included tree age (T), but its quadratic term (T2 ) and tree height (H, here a surrogate of area) were not systematically included. bsim, but not bsne, correlated with host-tree age, and both bsim and bsne correlated with geo graphical distance. Main conclusions: Tree age was consistently included in all of the best-fit models, reflecting the progressive increase in epiphyte bryophyte species richness through time. The limited contribution of T2 and H to the best models suggests that compe tition for space is not a key factor on mature trees. The correlation of bsim, but not bsne, with host-tree age, and of bsim and bsne with distance among trees, suggests that variation in species composition is caused by (1) temporal community shifts due to allogenic drivers and (2) dispersal limitations, which are reflected by the higher similarity of the epiphyte communities on clustered trees rather than by an increasing probability of colonization with tree age. Since actual ancient laurel for ests may no longer exist in Madeira, the conservation of clusters of late-succes sional trees, enhancing connectivity at small spatial scales, is of utmost importance for the conservation and recovery of the unique laurel forest epiphytic flora.info:eu-repo/semantics/publishedVersio

Intraspecific genetic variation in complex assemblages from mitochondrial metagenomics: comparison with DNA barcodes

Metagenomic shotgun sequencing, using Illumina technology, and de novo genome assembly of mixed field-collected amples of invertebrates readily produce mitochondrial genome sequences, allowing rapid identification and quantification of species diversity. However, intraspecific genetic variability present in the specimen pools is lost during mitogenome assembly, which limits the utility of ‘mitochondrial metagenomics’ for studies of population diversity. 2. Using 10 natural communities (>2600 individuals) of leaf beetles (Chrysomelidae), DNA variation in the mitochondrial cox1-5’ ‘barcode’ was compared for Sanger sequenced individuals and Illumina shotgun sequenced specimen pools. 3. Generally, only a single mitochondrial contig was assembled per species, even in the presence of intraspecific variation. Ignoring ambiguity from the use of two different assemblers, the cox1 barcode regions from these assemblies were exact nucleotide matches of a Sanger sequenced barcode in 90.7% of cases, which dropped to 76.0% in assemblies from samples with large intra and interspecific variability. Nucleotide differences between barcodes from both data types were almost exclusively in synonymous 3rd codon position, although the number of affected sites was very low, and the greatest discrepancies were correlated with poor quality of Sanger sequences. 4. Unassembled shotgun reads were also used to score single nucleotide polymorphisms and to calculate intraspecific nucleotide diversity (pi) for all available populations at each site. These values correlated with Sanger sequenced cox1 variation but were significantly higher. 5. Overall, the assemblage-focused shotgun sequencing of pooled samples produced nucleotide variation data comparable to the well-established specimen-focused Sanger approach. The findings thus extend the application of mitochondrial metagenomics of complex biodiversity samples to the estimation of diversity below the species level

Assessing the nonlinear decay of community similarity: permutation and site-block resampling significance tests

Modelling how community similarity decays with spatial distance is a key tool for the study of the processes behind community variation (beta diversity). Distance-decay models are computed from pairwise metrics (i.e. community similarity and spatial distance between localities) and hence suffer from pairwise dependence in the data, precluding the use of standard significance tests. Besides, distance-decay patterns are inherently nonlinear because similarity is bounded between 1 and 0. However, the only standard method to assess model significance under pairwise dependency is the Mantel test, which considers a linear model. To allow the use of nonlinear models in the assessment of distance-decay patterns, we introduce here a nonlinear significance test combining a pseudo-R2 statistic with either permutations or block-site resampling with replacementWe thank Xavier Picó, Christine Meynard, Simone Fattorini and two anonymous reviewers for insightful comments and suggestions to earlier versions of the manuscript. This research was supported by the Spanish Ministry of Science and Innovation and the European Regional Development Fund (ERDF) through grants CGL2016-76637-P and PID2020-112935GB-I00, PID2020-116587GB-I00 and a FPI scholarship to S.M.-S (BES-2017-081643). R.M.D. was supported by the Spanish Ministry of Education through a FPU scholarship (Ref.: FPU17/03016; Ministry of Education)S

Temporay ponds from Doñana National Park : a system of natural habitats for the preservation of aquatic flora and fauna

Mediterranean temporary ponds are a priority habitat under the European Union Habitats Directive, but those of natural origin are scarce, as many of them have been destroyed or transformed into permanent waters. The aim of this study is to highlight the conservation value of the system of temporary ponds in Doñana National Park, where more than 3000 water bodies may be filled during wet years. They are located on soils of aeolian origin where water persistence is favoured by the presence of an argilic semi permeable horizon and by a relic clay-rich sandy layer. Temporary ponds can be classified across a wide hydroperiod gradient. Most ponds fill with autumnal or winter rains and persist up to late spring or summer, and only a few may persist through summer. Eight of the 11 amphibian species of this area require temporary ponds for breeding. More than 124 taxa ofmacroinvertebrates have been recorded, coleopterans (56 taxa) and heteropterans (19 taxa) being the richest taxonomic groups. Several zoop1ankton species are endemic to this kind of habitats, such as the copepod Dussartius baeticus and the rotifer Lecane donyanensis. Regarding vegetation, at least 55 hydrophytes species were identified in the ponds sampled, and also some species endemic to SW Iberian Peninsula (Callitriche regis-jubae. Scorzonerajistulosa, Callitriche lusitanica) and others are in relic situation (Hydrocharis morsus-ranae, Thorella verticillato-inundata, Lemna trisulca). The conservation value of these ponds is highlighted by the large variety of protected ancl!or rare species of fiora and fauna, which are favoured by a high pond abundance and connectivity.Las lagunas temporales mediterráneas son hábitats prioritarios incluidos en la Directiva de Hábitats de la Unión Europea. que han sido frecuentemente destruídos o transformados en medios permanentes. siendo actualmente escasos los de origen natural. Este estudio pretende resaltar la importancia que tiene el sistema de charcas temporales del Parque Nacional de Doñana en la conservación de flora y fauna acuáticas. Este sistema comprende más de 3000 cuerpos de agua en años lluviosos, localizándose en las zonas de origen eólico, donde la permanencia del agua se ve favorecida por la presencia en sus suelos de un horizonte argz1ico y semipermeable y por una capa arenosa relicta rica en arcillas. Las lagunas temporales se pueden clasificar en función de su amplio gradiente de hidroperiodo. La mayoría de ellas se llenan con las lluvias de otoño o invierno y pueden permanecer hasta el final de la primavera o principios del verano y sólo algunas pueden mantener agua en verano. Las lagunas temporales son los hábitats de reproducción de ocho de las 11 especies de anfibios que se encuentran en Doñana. Se registraron más de 124 taxa de maeroinvertebrados, entre los que los coleópteros (56 taxa) y heterópteros (19 taxa) fueron los grupos taxonómicos con mayor número de especies. En el zooplancton. destacan especies endémicas de este área, como el copépodo Dussartius baeticus y el rotífero Lecane donyanensis. Entre las especies vegetales características de las lagunas temporales se han identificado más de 55 hidrójitos, encontrándose además algunos endemismos del suroeste ibérico (Callitriche regis-jubae, Scorzonera fistulosa, Callitriehe lusitanica) , así como especies amenazadas (Hydroeharis morsus-ranae, Thorella verticillato-inundata, Lemna trisulca). Las lagunas temporales de Doñana son de gran importancia para la conservación de un amplio número de especies protegidas y singulares de su flora y fauna acuática, que se ven favorecidas por la gran abundancia y conectividad de medios acuáticos