Descripción: Three species of Cercophora were found during a survey of the biodiversity of microfungi in northwest Argentina. Cercophora argentina possesses a unique combination of morphological characters and is described as a new species, while C. costaricensis and C. solaris are reported as new records for Argentina. Other species of Cercophora known from this region include C. natalita and C. coprogena, which is fully illustrated for the first time and determined herein to be a synonym of C. californica. All other species are described and illustrated. © 2011 by The Mycological Society of America.

Descripción: A list of 32 species of Heteroptera captured with pitfall traps at INTA (Instituto Nacional de Tecnología Agropecuaria) Delta del Paraná (Partido de Campana, Buenos Aires) is presented in this paper. Two species are mentioned as a first record for the province: Fulvius bisbistillatus (Stål) (Miridae) and Pselliopus ornaticeps (Stål) (Reduviidae). Also an analysis of Spearman rank correlation ® and correspondence analysis is made, to assess the spatial and temporal variation of Heteroptera communities of different selected land uses.

Descripción: Nearly all data regarding land-plant turnover across the Cretaceous/Paleogene boundary come from western North America, relatively close to the Chicxulub, Mexico impact site. Here, we present a palynological analysis of a section in Patagonia that shows a marked fall in diversity and abundance of nearly all plant groups across the K/Pg interval. Minimum diversity occurs during the earliest Danian, but only a few palynomorphs show true extinctions. The low extinction rate is similar to previous observations from New Zealand. The differing responses between the Southern and Northern hemispheres could be related to the attenuation of damage with increased distance from the impact site, to hemispheric differences in extinction severity, or to both effects. Legacy effects of the terminal Cretaceous event also provide a plausible, partial explanation for the fact that Paleocene and Eocene macrofloras from Patagonia are among the most diverse known globally. Also of great interest, earliest Danian assemblages are dominated by the gymnosperm palynomorphs Classopollis of the extinct Mesozoic conifer family Cheirolepidiaceae. The expansion of Classopollis after the boundary in Patagonia is another example of typically Mesozoic plant lineages surviving into the Cenozoic in southern Gondwanan areas, and this greatly supports previous hypotheses of high latitude southern regions as biodiversity refugia during the end-Cretaceous global crisis. © 2012 Barreda et al.

Descripción: Eleven Oxalis L. species from the province of Buenos Aires (Argentina) were investigated with scanning and transmission electron microscopes. We identified four different types and two subtypes of orbicules. We conclude that the close morphological similarity between these species is also reflected in their orbicules, and we suggest that the orbicules morphology may be a useful character in systematic studies.

Descripción: Phytotelmata, or plant-held waters, are considered to be good model systems for the study of community ecology. The fauna of these natural container habitats, particularly the mosquitoes, have been extensively investigated in tropical regions, but there is little known about them in temperate South America. We assessed the structure of immature mosquito communities in leaf axils, tree holes, and bamboo stumps from a temperate wetland of Argentina. A total of 4,330 immature mosquitoes were collected among the 2,606 phytotelmata inspected. Leaf axils of eight plant species and tree holes were larval habitats for nine mosquito species belonging to the genus Culex, Wyeomyia, Isostomyia, and Toxorhynchites. The mosquito communities showed richness ranging from one to four species. Marked differences were detected in the plant specificity for the species collected. Some of them were exclusively found in one plant species (Isostomyia paranensis in Scirpus giganteus), whereas others were collected in up to five plant species but belonging to the same phytotelm class, the leaf axils. Those from tree holes are well-known dwellers of artificial containers and ground water habitats, such as Culex pipiens. Our results support the idea of low mosquito richness in phytotelmata from temperate regions in comparison with tropical areas, but the observed specificity patterns echo the findings of tropical forests. © 2011 The Society for Vector Ecology.

Descripción: ABSTRACT: How species similarity changes between habitats along environmental gradients is still a central challenge in ecological studies. We assessed whether marsh plant characteristics are associated with geographic changes in environmental conditions and whether there are environmental factors associated with marsh-inland dissimilarity in species composition. Field samples of vegetation were collected at 6 sites along the SW Atlantic to determine plant characteristics (cover, tallness, richness and α-diversity), and marsh-inland dissimilarity (β-diversity) in species composition was calculated. PERMANOVA analysis showed that plant assemblage changes among sites. Forward stepwise multiple regression analysis showed that in lower marsh, plant cover increased in association with tidal range and decreased in association with salinity. In the high marsh, plant cover decreased in association with tidal range, salinity and with minimum temperatures. Plant richness increased in association with tidal range and with marsh area, while α-diversity decreased in association with precipitation and increased with salinity. Beta-diversity, estimated by SIMPER analysis, increased in association with precipitation and decreased with salinity and daily thermal amplitude. We present evidence that there is an increase in a-diversity but a decrease in β-diversity with environmental severity among co-specific marshes distributed along the SW Atlantic coast. Thus, communities developing in more benign conditions, regardless of their low local diversity, may increase biodiversity at a landscape scale by decreasing their similarities.© Inter-Research 2013. www.int-res.com.

Descripción: Most insects' assemblages differ with forest type and show vertical stratification. We tested for differences in richness, abundance and composition of hymenopteran families and mymarid genera between sugar maple (Acer saccharum) and white pine (Pinus strobus) stands and between canopy and understory in northeastern temperate forests in Canada. We used flight interception traps (modified malaise traps) suspended in the canopy and the understory in a split-split block design, with forest type as the main factor, forest stratum as the first split factor, and collection bottle location as the second split factor. Hymenopteran families and mymarid genera differed in their diversity depending on forest type and stratum. Both family and genera richness were higher in maple than in pine forests, whereas family richness was higher in the canopy and top bottles and generic richness was higher in the understory and bottom bottles. Multivariate analysis separated samples by forest type, vegetation stratum, and bottle location. Family composition showed 77% similarity between forest types and 73% between the canopy and understory. At the lower taxa level, mymarid genera showed only 47% similarity between forest types and 40% between forest strata, indicating vertical stratification and relatively high β-diversity. Our study suggests that hymenopteran diversity and composition is strongly dependent on forest type and structure, making flying members of this order particularly vulnerable to forest management practices. It also shows that insect assemblage composition (especially at low-taxon levels), rather than relative abundance and richness, is the community attribute most sensitive to forest type and vertical stratification. © 2007 Entomological Society of America.

Descripción: Background: Functional genetic markers have important implications for genetic analysis by providing direct estimation of functional diversity. Although high throughput sequencing techniques for functional diversity analysis are being developed nowadays, the use of already well established variable markers present in candidate genes is still an interesting alternative for mapping purposes and functional diversity studies. SSR markers are routinely used in most plant and animal breeding programs for many species including Eucalyptus. SSR markers derived from candidate genes (SSR-CG) can be used effectively in co-segregation studies and marker-assisted diversity management. Results: In the present study, eight new non reported SSRs were identified in seven candidate genes for wood properties in Eucalyptus globulus: cinnamoyl CoA reductase (CCR), homocysteine S-methyltransferase (HMT), shikimate kinase (SK), xyloglucan endotransglycosylase 2 (XTH2), cellulose synthase 3 (CesA3), glutathione S-transferase (GST) and the transcription factor LIM1. Microsatellites were located in promoters, introns and exons, being most of them CT dinucleotide repeats. Genetic diversity of these eight CG-derived SSR-markers was explored in 54 unrelated genotypes. Except for XTH2, high levels of polymorphism were detected: 93 alleles (mean of 13.1 sd 1.6 alleles per locus), a mean effective number of alleles (Ne) of 5.4 (sd 1.6), polymorphic information content values (PIC) from 0.617 to 0.855 and probability of Identity (PI) ranging from 0.030 to 0.151. Conclusions: This is the first report on the identification, characterization and diversity analysis of microsatellite markers located inside wood quality candidate genes (CG) from Eucalyptus globulus. This set of markers is then appropriate for characterizing genetic variation, with potential usefulness for quantitative trait loci (QTL) mapping in different eucalypts genetic pedigrees and other applications such as fingerprinting and marker assisted diversity management. © 2012 by Pontificia Universidad Católica de Valparaíso, Chile.

Descripción: Possible consequences of climate change in one of the world's largest wetlands (Ibera, Argentina) were analysed using a multi-scale approach. Climate projections coupled to hydrological models were used to analyse variability in wetland water level throughout the current century. Two potential scenarios of greenhouse gas emissions were explored, both resulting in an increase in the inter-annual fluctuations of the water level. In the scenario with higher emissions, projections also showed a long-term negative trend in water-level. To explore the possible response of biota to such water-level changes, species-area relationships of flora and aerial censuses of macro-fauna were analysed during an extraordinary dry period. Plant species richness at the basin scale was found to be highly resistant to hydrological changes, as the large dimension of the wetland acts to buffer against the water-level variations. However, local diversity decreased significantly with low water levels, leading to the loss of ecosystem resilience to additional stressors. The analysis of macro-fauna populations suggested that wetland provides refuge, in low water periods, for the animals with high dispersal ability (aquatic and migratory birds). On the contrary, the abundance of animals with low dispersal ability (mainly herbivorous species) was negatively impacted in low water periods, probably because they are required to search for alternative resources beyond the wetland borders. This period of resource scarcity was also related to increased mortality of large mammals (e.g. marsh deer) around water bodies with high anthropogenic enrichment and cyanobacteria dominance. The synergy between recurrent climatic fluctuations and additional stressors (i.e. biological invasions, eutrophication) presents an important challenge to the conservation of neotropical wetlands in the coming decades. © 2013 Úbeda et al.