Dinámica espacio temporal de la comunidad de macroinvertebrados de las lagunas temporal de Doñana

Peer reviewe

Relationships between hydroperiod length, and seasonal and spatial patterns of beta-diversity of the microcrustacean assemblages in Mediterranean ponds

Temporary ponds are unpredictable habitats that exhibit inundation periods of variable duration (hydroperiods). We hypothesised that changes in microcrustacean assemblages, namely among ponds (spatial variation) and within ponds at a monthly scale (intra-annual variation), would differ according to hydroperiod length. We found that the microcrustacean assemblages of the study ponds demonstrated distinctive individual patterns that were dependent on monthly variation. During pond filling, species turnover was particularly high in short-hydroperiod ponds, probably due to the fast hatching of the initial pool of species, which seemed to determine subsequent species succession. Some of the long-hydroperiod ponds were able to hold water during the summer, which meant that they could harbour adult microcrustaceans in the early autumn, in contrast to the recently filled ponds; species turnover could thus increase at the onset of the inundation cycle. In the summer, species turnover decreased (while the contribution of nestedness to β-diversity increased) because only a few tolerant species were able to withstand the poor water quality found in drying ponds. We suggest that preserving the broader hydroperiod gradient, by protecting ponds with different environmental conditions within each hydroperiod category, would safeguard the ecological dynamics of the microcrustacean assemblages found in temporary pondsPeer reviewe

Biases in global effects of exotic species on local invertebrates: a systematic review

Historical gaps and biases in the literature may have influenced the current knowledge of the impacts of invaders on global biodiversity. We performed a systematic review and compiled the main gaps and biases in the literature and the reported negative, neutral and positive effects of exotic species on local invertebrates worldwide. We analysed the relation of these reported effects to the biogeographical origin of the exotic species, the environmental characteristics of the invaded area, the trophic level of the exotic species and of the invaded local fauna, and the elapsed time after first introduction. We analysed 1276 publications comprising 2984 study cases. From these, 1786 cases included “control” situations (without exotics) and provided quantitative supporting evidence of the effects of exotic species on local invertebrates. The main gaps in the literature included tropical and arid climates, estuaries and marine ecosystems, as well as exotic species coming from Neotropical, Australian, Oriental, Ethiopian and Antarctic regions. Carnivorous and herbivorous species were underreported as exotic species and as impacted invertebrates. The considered variables were mostly unrelated to the reported effects, suggesting that the effects of exotic species on local invertebrates are heterogeneous and not unidirectional. Many impacted invertebrates were assemblages of undefined composition in terms of the native or exotic nature of the invaded organisms. Further avenues to reduce the identified biases in the current knowledge about the effects of exotic species on local invertebrates are also indicatedThe MF’s grant was supported by the Conselho Nacional de Desenvolvimento Cientı´fico e Tecnológico-CNPq (401045/2014-5), program Ciência sem Fronteiras, and by the Universidad de Alcala´. LMB has been supported by the National Institutes for Science and Technology (INCT) in Ecology, Evolution and Biodiversity Conservation (MCTIC/CNPq, 465610/2014-5, FAPEG) and by a CNPq Grant (304314/2014-5

Dinámica espacio temporal de la comunidad de macroinvertebrados de las lagunas temporales de Doñana

Las lagunas temporales son medios acuáticos de pequeño o mediano tamaño que sufren una fase de desecación recurrente de longitud variable y que suele ser impredecible en su forma y duración (Williams 1997). El periodo de inundación de los medios acuáticos temporales puede definirse por un conjunto de características que algunos autores engloban en lo que denominan “hidrorégimen” (ver Wissinger 1999; Hulsmans et al. 2008; Vanschoenwinkel et al. 2009): 1) La regularidad de la inundación es la frecuencia anual de la inundación-desecación; 2) La previsibilidad de la inundación es la probabilidad de que la inundación se produzca en el mismo momento cada año así como la probabilidad de que un cuerpo de agua se inunde todos los años; 3) El hidroperiodo es la duración del periodo de inundación desde la formación hasta la desecación de las lagunas. La principal fuente de variabilidad del “hidrorégimen” viene determinada por la gran variabilidad del hidroperiodo (Hulsmans et al. 2008). En un área se puede detectar una amplia variabilidad en hidroperiodo entre las diferentes lagunas que componen un sistema. A su vez, el hidroperiodo de estas lagunas puede variar con la estacionalidad de la abundancia y distribución de las precipitaciones y de la evaporación, y según la cantidad de la precipitación anual. Esta complejidad hace que algunos autores hayan definido el hidroperiodo como eventos separados a lo largo de un mismo año (Boix et al. 2004) o como la duración media entre diferentes años (Schneider 1999), en vez de considerar la duración total de la inundación en el ciclo anual (Florencio et al. 2009). Las lagunas pueden considerarse permanentes, semipermanentes o temporales (Wissinger 1999) en función de la longitud del hidroperiodo. Pero dentro de las lagunas temporales existe un amplísimo gradiente de hidroperiodo que abarca desde las lagunas de duración más efímera, que se inundan de manera esporádica, hasta las lagunas semipermanentes que sólo se secan en años de sequía extrema (Grillas et al. 2004; Williams 2006). La longitud del hidroperiodo constituye un factor importante para determinar la composición faunística que albergan las lagunas temporales (Wiggins et al. 1980; Grillas et al. 2004; Williams 2006)

Spatio-temporal nested patterns in macroinvertebrate assemblages across a pond network with a wide hydroperiod range

Nestedness has been widely used to measure the structure of biological communities and occurs when species-poor sites contain subsets of species-rich ones. Here, we examine nested patterns across the macroinvertebrate assemblages of 91 ponds in Doñana National Park, Spain, and explore temporal variation of nestedness and species richness in 19 temporary ponds over 2 years with differing rainfall. Macroinvertebrate assemblages were significantly nested; both pond spatial arrangement and environmental variation being important in driving nested patterns. Despite the nested structure observed, a number of taxa and ponds deviate from this pattern (termed idiosyncratic), by occurring more frequently than expected in species-poor sites, or having assemblages dominated by species largely absent from species-rich sites. Aquatic adults of winged insects, capable of dispersal, were more highly nested than non-dispersing taxa and life-history stages. Idiosyncratic taxa were found in ponds spanning a wide range of hydroperiods, although nestedness was higher in more permanent waterbodies. Monthly sampling demonstrated a gradual increase of species richness and nestedness from pond filling to April-May, when the most temporary ponds started to dry. Although the degree of nestedness of individual pond assemblages varied from month to month, the overall degree of nestedness in the two study years was practically identical despite marked differences in hydroperiod. Our results suggest that differential colonization and environmental variation are key processes driving the nested structure of Doñana ponds, that macroinvertebrate assemblages change in a predictable manner each year in response to cycles of pond wetting and drying, and that connectivity and environmental variability maintain biodiversity in pond networks. © 2010 Springer-Verlag.Peer Reviewe

Factores mediadores en el aprendizaje cooperativo: los estilos de conducta interpersonal

La mayoría de las investigaciones sobre el aprendizaje cooperativo se han centrado por un lado, en la comparación de situaciones cooperativas, competitivas e individualistas, y por otro lado en las aplicaciones del aprendizaje cooperativo sobre variables académicas y sociales. En los años noventa aparecen, por primera vez, y en minoría, investigaciones que se dirigen principalmente a resolver las cuestiones relativas a la eficacia del aprendizaje cooperativo y los factores implicados. Este trabajo se enmarca dentro de esta última posición y pretende ofrecer una pequeña aportación a esta línea de investigación emergente. Sin embargo, dentro de este grupo de investigaciones, echamos de menos trabajos que demuestren la influencia de variables interpersonales en los resultados del aprendizaje cooperativo. Consideramos relevante el carácter de los participantes: introvertido, extrovertido, independiente, gregario, tímido, etc. Pensamos que estas dimensiones interpersonales pueden ser predictoras del éxito y fracaso de las situaciones de aprendizaje cooperativo, además de ayudarnos a comprender comportamientos individuales e interacciones dentro del grupo. Con nuestra investigación pretendemos encontrar relaciones entre estas variables interpersonales con los roles desempeñados en el grupo, las conductas verbales manifestadas a lo largo de la interacción, el rendimiento y la percepción individual de la madurez grupal.Most of the researches into cooperative learning have been centered, on the one hand on the comparison between cooperative, competitive and individual situations, and on the other hand on the applications of the cooperative learning on academic and social variables. In the 1990s, the first researches appeared which main objective was to solve questions concerning the efficiency of cooperative learning and the related factors. This piece of work is set in this last idea and it tries to offer a little contribution to this emerging research. However, within this group of researches we miss some which prove the influence of interpersonal variables on cooperative learning results. We consider the participants characters to be noteworthy: extrovert, introverted, independent, with no initiative, shy,... We think that these interpersonal aspects may predict the success or the failure of some cooperative learning situations, as well as they will help us in the understanding of some individual behaviours and interactions within the group. With our research we intend to find connections between these interpersonal variables and the roles played within the group, verbal behaviours shown throughout the interaction, the performance and the individual perception of the group maturity

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

Biodiversity patterns of macroinvertebrate assemblages in natural and artificial lentic waters on an Oceanic Island

The Azorean islands have been historically affected by human activities, mainly due to the combined effects of habitat degradation and fragmentation, and the introduction of exotic species. We here aim to analyze the role of environmental characteristics and spatial descriptors in supporting regional biodiversity of macroinvertebrates by considering natural ponds and artificial tanks. After the monthly variation of macroinvertebrate assemblages was assessed in three temporary and two permanent ponds in the Azorean island of Terceira during a complete inundation-desiccation annual cycle, the assemblage differences of 12 ponds (three temporary and nine permanent ponds) and 8 closely-located artificial tanks were analyzed across a range of landscape disturbances. Macroinvertebrate assemblages were found to differ according to hydroperiod and sampled months. Although the former explained the highest variance, macroinvertebrate differentiation by hydroperiod was also dependent on the study month. Our results also revealed a consistent monthly pattern of species replacement. However, the contribution of nestedness to the macroinvertebrate β-diversity was notable when temporary ponds were close to desiccation, probably indicating a deterministic loss of species due to the impoverished water conditions of the ponds facing desiccation. When the macroinvertebrate assemblages were analyzed in relation to physico-chemical variations and spatial descriptors, the artificial tanks were not clearly segregated from the natural ponds, and only differentiated by pH differences. In contrast, those natural ponds exhibiting high concentrations of total phosphorous (likely signs of anthropization) also discriminated the ordination of ponds in a distance-based redundancy analysis, and showed impoverished assemblages in comparison with well-preserved ponds. The macroinvertebrate assemblages of the natural ponds showed a significant spatial pattern, but this spatial influence was not significant when tanks and ponds were considered together. Our results suggest that tanks may act as possible reservoirs of biodiversity during the desiccation period of temporary ponds, but are unable to establish successful populations. These fishless permanent tanks can complement the conservation of a biodiversity that is largely maintained by the pristine high-altitude natural ponds. The establishment of a guideline for conservation management that also considers the artificial tanks is necessary to benefit the local and regional Azorean macroinvertebrate diversit