Phylogenetic analysis of Chloraeinae (Orchidaceae) based on plastid and nuclear DNA sequences

The phylogenetic relationships of subtribe Chloraeinae, a group of terrestrial orchids endemic to southern South America, have not been satisfactorily investigated. A previous molecular phylogenetic analysis based on plastid DNA supported the monophyly of Chloraeinae and Gavilea, but showed that Chloraea is non‐monophyletic and that the sole species of Bipinnula analysed is sister to Geoblasta. However, that analysis included only 18 of the 73 species belonging to this subtribe. Here, the phylogenetic relationships of Chloraeinae were assessed by analysing aproximately 7500 bp of nucleotide sequences from nuclear ribosomal internal transcribed spacer (ITS) and plastid DNA (rbcL, matK, trnL‐trnF, rpoB‐trnC) for 42 species representing all four currently accepted genera of Chloraeinae and appropriate outgroups. Nuclear and plastid data were analysed separately and in combination using two different methods, namely parsimony and Bayesian inference. Our analyses support the monophyly of Chloraeinae and their inclusion in an expanded concept of Cranichideae, but none of the genera of Chloraeinae that includes more than one species is monophyletic. Gavilea and Bipinnula are paraphyletic, with Chloraea chica nested in Gavilea and Geoblasta penicillata in Bipinnula. As currently delimited, Chloraea is polyphyletic. The taxonomic changes proposed recently are for the most part not justifiable on phylogenetic grounds, except for recognition of the monotypic genus Correorchis. The lack of resolution for the relationships among species of ‘core’Chloraea suggests a relatively recent diversification of this group. The current generic classification is in need or revision, but additional study is advisable before carrying out further taxonomic changes. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 168 , 258–277.     

Primary production dynamics and climate variability: ecological consequences in semiarid Chile

Increase in rainfall variability has important consequences for organisms in arid and semiarid regions around the world. In South American and Australian deserts, the El Niño/Southern Oscillation (ENSO) phenomenon greatly influences rainfall patterns, and therefore the dynamics of plant communities. However, the field data needed to assess the effect of climate change on vegetational patterns is difficult to obtain because of the large spatial scale required for such studies. Normalized Difference Vegetation Index (NDVI) characteristics allow the use of several indexes related to vegetational structure. Due to its direct relationship with primary productivity, it is possible to obtain several measures of annual productivity. These include annual plant yield, annual maximum yield, onset of 'greening-up' and senescence phases, length of the 'green' season, vegetation peak, and therefore, the periods when more or less food is available for herbivores. After verification with ground-truth measures, we used NDVI data from two semiarid localities in north-central Chile (Fray Jorge and Aucó) to determine the relationship between rainfall patterns and vegetation cover and productivity related to El Niño phenomenon. With this information we gauge the influence of climatic processes on primary productivity in western South America, an area subject to strong climate variability. We predict significant variation in Chilean semiarid regions due to climate change, affecting mainly the extent and timing of annual growth season of vegetation, and also including a shorter and delayed greening-up season. Also, we predict that important decreases in rainfall levels will not have strong effects on primary production in these semiarid ecosystems.     

Local richness and distribution of the lizard fauna in natural habitat mosaics of the Brazilian Cerrado

We investigate local lizard richness and distribution in central Brazilian Cerrado, harbouring one of the least studied herpetofaunas in the Neotropical region. Our results are based on standardized samplings at 10 localities, involving 2917 captures of 57 lizard species in 10 families. Local richness values exceeded most presented in earlier studies and varied from 13 to 28 species, with modal values between 19 and 28 species. Most of the Cerrado lizard fauna is composed of habitat‐specialists with patchy distributions in the mosaic of grasslands, savannas and forests, resulting in habitat‐structured lizard assemblages. Faunal overlap between open and forested habitats is limited, and forested and open areas may act as mutual barriers to lizard distribution. Habitat use is influenced by niche conservatism in deep lineages, with iguanians and gekkotans showing higher use of forested habitats, whereas autarchoglossans are richer and more abundant in open habitats. Contrary to trends observed in Cerrado birds and large mammals, lizard richness is significantly higher in open, interfluvial habitats that dominate the Cerrado landscape. Between‐localities variation in lizard richness seems tied to geographical distance, landscape history and phylogenetic constraints, factors operating in other well‐studied lizard faunas in open environments. Higher richness in dominant, open interfluvial habitats may be recurrent in Squamata and other small‐bodied vertebrates, posing a threat to conservation as these habitats are most vulnerable to the fast, widespread and ongoing process of habitat destruction in central Brazil.     

Demography of the clonal palm Geonoma brevispatha in a Neotropical swamp forest

Abstract We expected that in clonal plants with the phalanx growth form, prereproductive ramets function as a meristem bank that helps buffer ramet demography against environmental fluctuations. Specifically, we evaluated four expectations for the forest understorey clonal palm Geonoma brevispatha in a swamp forest in south‐eastern Brazil. Our expectations were are follows: (i) the vital rates of prereproductive ramets are more responsive to genet‐related characteristics (genet size, distance and size of the nearest genet neighbour, and reproductive ramet survivorship) than to environmental variables (canopy openness, basal area of small trees, flooding, and distance and size of the nearest large tree neighbour), whose effects are expected to affect ramet dynamics indirectly through physiological integration; (ii) the progress of prereproductive ramets to later stages is dependent on the death of reproductive ramets; (iii) the population dynamics of G. brevispatha is resistant to significant interannual changes in the vital rates of ramets, (i.e. the occurrence of good and bad years); and (iv) there are large negative covariances among demographic transitions within a given year, as well as between years, reflecting the flexibility of G. brevispatha to adjust to environmental variability. Expectations 1, 2 and 4 were confirmed, while expectation 3 was only partially confirmed. Matrix models predicted that the growth rate of the overall ramet population was significantly greater than unity in the first study year, but it was significantly smaller than 1.0 in the second study year. Ramet population growth rates at the level of individual genets were greater than unity in the majority of genets in the first year, but in the second year genets with growth rates smaller than unity prevailed. Ramet population dynamics seems to be resistant to the succession of good and bad years; in effect, the presence of a meristem bank of ramets helps stabilize λ.     

Exoerythrocytic Development of Plasmodium Gallinaceum Sporozoites In A Chicken Fibroblast Cell Line and Inhibition of the Cell Invasion By Specific Anti-Sporozoite Monoclonal Antibodies

ABSTRACT. Cultivation of the Plasmodium gallinaceum exoerythrocytic forms from sporozoites was attempted in three diferent cell lines: HEPG2-A16 (from a human hepatoma), VERO (monkey kidney epithelial cells) and SL-29 (chicken embryo fibroblast cells). the sporozoites in vaded all three cell types but their development into exoerythrocytic forms ocurred only in the SL-29 cells. In the presence of specific monoclonal antibodies against the major circumsporozoite protein, there were varying degrees of inhibition of parasite invasion of the SL-29 cells. of seven monoclonal antibodies tested, two completely inhibited cell invasion at high concentrations and caused intense inhibition at concentrations as low as 2.5 μg/ml, four caused intense inhibition at these various concentrations, and one had no effect on sporozoite invasion.     

Demonstration of serum albumin (ALB) polymorphism in wild rabbits, Oryctolagus cuniculus, by means of isoelectric focusing

Summary. Genetic polymorphism of serum albumin was demonstrated by isoelectric focusing in wild rabbit populations from Portugal and England. Gene frequencies were estimated to be (1) ALB*1 = 0.47, ALB*2 = 0.49, ALB *3 = 0.04, in Portugal, and (2) ALB*1 = 0.60 and ALB*2 = 0.40, in England. One hundred Portuguese domestic rabbits of mixed breeds were all of ALB 1 type.     

Cryptic diversity within the endemic prehensile‐tailed gecko Urocotyledon inexpectata across the Seychelles Islands: patterns of phylogeographical structure and isolation at the multilocus level

The deciphering of the process of genetic differentiation of species with insular distributions is relevant for biogeographical and conservation reasons. Despite their importance as old gondwanic islands and part of the western Indian Ocean biodiversity hotspot, little is known about the genetic structure of taxa from the Seychelles Islands. We have examined the patterns of structure and isolation within Urocotyledon inexpectata (Reptilia: Geckkonidae), an endemic species from this archipelago. Genetic diversity was screened from populations across the archipelago for both mitochondrial and nuclear genes. Gene genealogies and model‐based inference were used to explore patterns and timings of isolation between the main lineages. High levels of genetic diversity were found for the mitochondrial and some of the nuclear markers. This species harbours at least two highly differentiated lineages, exclusively distributed across the northern and southern groups of the islands. The main split between these was dated back to the Miocene–late Pliocene, but isolation events throughout the Pliocene and Pleistocene were also inferred. Migration between groups of islands was apparently nonexistent, except for one case. The low dispersal capabilities of this species, together with the intrinsic fragmented nature of its geographical distribution, seem to have resulted in highly structured populations, despite the cyclic periods of contact between the different island groups. These populations may currently represent more than one species, making U. inexpectata another example of a morphologically cryptic lineage with deep genetic divergence within gekkonids. The observed patterns suggest a hypothetical biogeographic scenario (of a main north–south phylogeographic break) for the Seychelles that can be further tested with the exploration of the phylogeographic structure of other Seychellois taxa. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 177–191.