Evolution of Stem and Leaf Structural Diversity: a Case Study in Lychnophorinae (Asteraceae)

Lychnophorinae occurs mainly in campos rupestres and cerrados of the Cerrado Domain (Brazil) and are species subject to fire occurrences and intense solar radiation, occupying acid and well-drained soils. Informative characters on the taxonomy of this subtribe were studied considering the leaf and stem morphology and anatomy. In addition, putative synapomorphies and features that probably determined the success of these species in occupying these habitats were identified. Samples of leaves and stems of 52 species were analyzed using usual techniques in plant anatomy. The reconstruction of ancestral states of characters was made in parsimony analysis using the phylogeny established for Lychnophorinae. The analyses indicated two distinct types of stems and a wide variation in foliar features, with the possible occurrence of three synapomorphies for the stems and 11 for the leaves. Adaptive pressures of restricted environments, where most species live, probably directed the evolution of morphological and anatomical diversity in Lychnophorinae.     

Three new species of <Emphasis Type="Italic">Ocotea</Emphasis> (Lauraceae) from the <Emphasis Type="Italic">campos rupestres</Emphasis> of Brazil

Three new hermaphrodite species of Ocotea (Lauraceae) from the campos rupestres of Brazil are described and illustrated: Ocotea pumila, which is known from Bahia state; and Ocotea colophanthera and Ocotea rupestris both from Minas Gerais state. Their diagnostic features are pointed out, and a discussion of their relationships to other species of Ocotea is provided.     

A new <Emphasis Type="Italic">Comanthera</Emphasis> (Eriocaulaceae) from the Espinhaço Range,Minas Gerais,Brazil

We describe and illustrate the new species Comanthera brunnea (Eriocaulaceae: Paepalanthoideae). This species is endemic to the sandy fields of the campos rupestres of the northeastern Espinhaço range in Minas Gerais, Brazil. We compare it with Comanthera suberosa, the morphologically most similar species, and with C. brasiliana, which also has similar features. The morphological variation, habitat, geographic distribution, and conservation status of this new species are discussed.     

Plant communities on ironstone outcrops: a diverse and endangered Brazilian ecosystem

Mountain areas are recognized centres of endemism and diversity on account of their isolation and altitudinal diversity. In tropical regions, mountain tops usually stand as islands of xeric vegetation among mesophytic assemblages. Unlike the vegetation growing on other rock outcrops lithologies, such as inselbergs (granite/gneiss) or campos rupestres (quartz/arenite), ironstone outcrop plant communities still lack systematic studies in Brazil. These outcrops (locally known as canga) share most of the characteristics of other rock outcrops, such as isolation and edapho-climatic harshness, but differ in that they are the object of opencast mining, and thus subjected to irrecoverable degradation. In addition, they are expected to harbour metal-tolerant and hyperaccumulator plant species. A botanical survey of two ironstone outcrop locations in the most important mining region of southeastern Brazil, the Iron Quadrangle, revealed a high within-site (138 and 160 species per site), and between-site diversity (only 27% of common species), totaling 64 families and 234 species among basal families and eudicots (154 species), monocots (68 species), and ferns (12 species). Canga crusts are rich in dicots, several of which play an important role in community structuring, together with the more usual monocot aggregations. Distinct plant communities are found associated to different microhabitats within the iron crust, depending primarily on the amount of soil and moisture retention in the different microtopographies. The environmental uniqueness, high diversity, lack of studies and rapid destruction of these ecosystems pose an immediate challenge for their conservation.     

Fire? They don't give a dung! The resilience of dung beetles to fire in a tropical savanna

1. Disturbance is a strong driver of community assembly and fire has long been recognised as one of the main disturbances of terrestrial ecosystems. This study tested the resilience of dung beetles to fire events in campos rupestres, which is a tropical savanna ecosystem that evolved under a frequent fire regime, by assessing the resistance and recovery of their communities. 2. Dung beetles were sampled before and after a fire event and the effect of fire on dung beetle richness, abundance, mean community biomass and composition was tested. The effects of time since last fire and fire frequency on the community were also tested. 3. No effect of fire occurrence, time since last fire and fire frequency on any community variable was found. 4. Some non‐mutually exclusive mechanisms promoting the resistance and recovery of dung beetles in campos rupestres could be acting in synergy. One potential mechanism is the mismatched seasonality between fire events and dung beetle occurrence, as fires occur during the dry season and dung beetles are present above ground during the rainy season. Furthermore, dung beetles are insects that remain buried during most of their lifetime, which could protect individuals from being burned. Another potential mechanism is the replacement of species in burned areas by the movement of individuals from unburned areas, attracted by resources and/or by metacommunity dynamics. 5. It is concluded that in this ‘fire‐dependent’ ecosystem, dung beetle communities are resilient to fire and seem not to be structured by this disturbance.     

Centres of Endemism in the Espinhaço Range: identifying cradles and museums of Asclepiadoideae (Apocynaceae)

Although the high diversity of neotropical plants is often associated with rain forests, another important location is open vegetation at mountain tops. In the present study, we investigated the phytogeographic patterns of the Espinhaço Range, in eastern Brazil, a region characterized by campos rupestres and marked by high levels of plant richness and endemism. Based on the occurrence of Asclepiadoideae (Apocynaceae) in a grid of 0.5º × 0.5º cells, we conducted cluster analyses and parsimony analysis of endemicity (PAE). We also calculated indexes of diversity and endemism and examined the distribution of palaeo- and neo-endemics. According to our data, the topographic gap between the Espinhaço Range of Minas Gerais and Bahia seems to be an important constraint for the dispersion of endemics, and the floristic similarity between northern Minas Gerais and Bahia is a result of species with broad distribution. Based on the seven areas of endemism that emerged from PAE, we defined five principal centres of endemism in the Espinhaço Range, including the region comprising Serra do Cipó and the Diamantina Plateau, in Minas Gerais, as the major Asclepiadoideae cradle, and Chapada Diamantina, in Bahia, as an Asclepiadoideae museum.     

Home‐ranges,population densities,vocal behavior,and post‐fledging movements of Cipo Canasteros (Asthenes luizae,Furnariidae), a rock‐specialist endemic of the highlands of eastern Brazil

Cipo Canasteros (Asthenes luizae, Furnariidae) have a fragmented and limited range restricted to the campos rupestres (rupestrian grasslands) habitat in the Brazilian highlands of the Espinhaço Range, and little is known about their behavior, ecology, and population biology. From March 2009 to November 2010, we monitored birds (24 banded and 22 radio‐tracked) at two study sites at Serra do Cipó in the state of Minas Gerais, Brazil, to estimate their home‐range sizes and population density, and describe their habitat use, natal dispersal behavior, and vocal behavior. We found an average density of 8.7 paired adults/km² in our study areas or 22.9 paired adults/km² when considering only used habitats. The sex ratio was male‐biased (males/total adults = 0.68), adults exhibited high site fidelity, home‐ranges averaged 4.0 ha (fixed kernel 95%) or 3.5 ha (95% minimum convex polygon) in size, and both sexes defended territories year‐round. We recorded four main types of songs, including two uttered more often during the breeding season. We monitored the natal dispersal of two males and one female who moved maximum distances of 1238 m, 780 m, and 1056 m, respectively, from natal areas. Our results confirm that Cipo Canasteros are restricted to the rocky‐outcrop habitat of the campos rupestres. In part due to their habitat specialization, Cipo Canasteros are considered Near Threatened, but other factors contributing to their demographic fragility include the small number, and probably low survival, of females and low reproductive success due to predation and brood parasitism by cowbirds. Given these threats, along with their specialized habitat and restricted range, the future conservation of Cipo Canasteros will likely depend on the extent to which their campos rupestres habitat can be conserved.     

Evolutionarily significant units of the critically endangered leaf frog Pithecopus ayeaye (Anura,Phyllomedusidae) are not effectively preserved by the Brazilian protected areas network

Protected areas (PAs) are essential for biodiversity conservation, but their coverage is considered inefficient for the preservation of all species. Many species are subdivided into evolutionarily significant units (ESUs) and the effectiveness of PAs in protecting them needs to be investigated. We evaluated the usefulness of the Brazilian PAs network in protecting ESUs of the critically endangered Pithecopus ayeaye through ongoing climate change. This species occurs in a threatened mountaintop ecosystem known as campos rupestres. We used multilocus DNA sequences to delimit geographic clusters, which were further validated as ESUs with a coalescent approach. Ecological niche modeling was used to estimate spatial changes in ESUs’ potential distributions, and a gap analysis was carried out to evaluate the effectiveness of the Brazilian PAs network to protect P. ayeaye in the face of climate changes. We tested the niche overlap between ESUs to gain insights for potential management alternatives for the species. Pithecopus ayeaye contains at least three ESUs isolated in distinct mountain regions, and one of them is not protected by any PA. There are no climatic niche differences between the units, and only 4% of the suitable potential area of the species is protected in present and future projections. The current PAs are not effective in preserving the intraspecific diversity of P. ayeaye in its present and future range distributions. The genetic structure of P. ayeaye could represent a typical pattern in campos rupestres endemics, which should be considered for evaluating its conservation status.     

Three new species of <Emphasis Type="Italic">Eupatorieae</Emphasis> (Compositae) from Brazil

Three new species of Eupatorieae (Asteraceae) were collected in the “campos rupestres” of the Cadeia do Espinha?o, Minas Gerais state, Brazil, in the Itacolomi State Park, located between the cities of Ouro Preto and Mariana, Minas Gerais, Brazil, during a floristic survey focusing on Compositae in this area. Eupatorium semiamplexifolium, Mikania badiniana, and Stevia alexii are described and illustrated.     

Fluctuating asymmetry in leaves and flowers of sympatric species in a tropical montane environment

Fluctuating asymmetry (FA) represents small, random variations in traits, presumably with bilateral symmetry, and is widely used as a tool to measure developmental instability in plants and animals. Because FA is a quick, simple and reliable measure, it has been frequently used for monitoring levels of environmental stress. This study investigated whether FA can be used as a predictor of individual developmental instability for four sympatric Melastomataceae species. To achieve that aim, 20 individuals of Trembleya laniflora, T. parviflora, Lavoisiera campos‐portoana and Tibouchina heteromalla were marked in southeastern Brazil and monitored before and during the flowering season. The FA index was calculated as the mean of the difference in the width or length between the left and right sides measured for each leaf or flower. All studied species exhibited asymmetry in the leaves and flowers, but the leaves of L. campos‐portoana and the petal width of T. heteromalla exhibited directional asymmetry, also an indicator of developmental instability. The highest level of leaf asymmetry was found in T. heteromalla and on flowers of L. campos‐portoana. None of the studied species exhibited a significant relationship between the FA level of the leaves and flowers on an individual basis, indicating that environmental and/or genetic sources of stress might act differently on different plant traits. For the studied species, measurements of FA can be suggested as useful tools to biomonitor levels of stress experienced by both leaves and flowers within the Melastomataceae family.     

High abundance of non-mycorrhizal plant species in severely phosphorus-impoverished Brazilian <Emphasis Type="Italic">campos rupestres</Emphasis>

Background and aims

We sought to describe the species and functional composition of Brazilian campos rupestres plant communities on severely nutrient-impoverished white sands, to test hypotheses relating plant communities and physiological adaptations to infertile soils. Based on recently-published information on a south-western Australian dune chronosequence, we hypothesised that campos rupestres plant communities would similarly contain a relatively large proportion of non-mycorrhizal species, because of the phosphorus-(P) impoverished nature of the soils. We also sought to test the hypothesis that many of these non-mycorrhizal species have high leaf manganese (Mn) concentrations as a consequence of carboxylate exudation to mobilise soil P.

Methods

We conducted flora surveys and quantified mycorrhizal status and foliar Mn concentrations in field sites with strongly-weathered sandy soils. Rhizosphere carboxylates were collected from glasshouse-grown plants to assess a potential correlation of carboxylates and leaf Mn concentrations.

Results

Soils were depleted of all major plant nutrients. Non-mycorrhizal plants were abundant in most field sites (mean relative cover = 48%). Vellozia species were dominant aboveground; belowground, roots were colonised more by dark septate endophytic fungi than by mycorrhizal fungi. From the field sites, foliar Mn concentrations in non-mycorrhizal species increased with decreasing soil P concentrations, but only when soil Mn concentrations were above a minimum threshold (exchangeable [Mn] above detection limit). Across all species, however, there was no relationship of foliar Mn concentrations with soil P concentrations.

Conclusions

Our hypothesis that white-sand campos rupestres communities contain a relatively large proportion of non-mycorrhizal plants was supported. Comparison with similar ecosystems in south-western Australia suggests that plant communities on severely P-impoverished sandy soils, despite differing evolutionary histories and little overlap in plant families, follow convergent evolutionary paths towards increasing abundance of non-mycorrhizal species.

     

Spatial analyses of the phylogenetic diversity of Minaria (Apocynaceae): assessing priority areas for conservation in the Espinhaço Range,Brazil

The protection of areas that shelter high evolutionary diversity represented by geographically and phylogenetically isolated lineages is becoming an important conservation strategy. Nevertheless, the spatial distribution of this component of biodiversity is still unknown for most groups, which limits its application for selecting priority areas to conserve. In the present study, we reconstructed the phylogeny of Minaria (Apocynaceae) based on plastid (trnH-psbA, rps16, trnS-trnG and trnD-trnT) and nuclear (ITS and ETS) DNA markers and 34 morphological characters, and analysed the geographic distribution of the phylogenetic diversity (PD) and endemism (PE) in this genus. Minaria includes 21 species that are highly concentrated in the Espinhaço Range, in eastern Brazil, most of which (～75%) are narrowly distributed. The spatial analyses of PD and PE of Minaria indicate four evolutionary relevant areas in this region. The Serra do Cipó and the Diamantina Plateau contain 10 endemic species and present the highest levels of PD. However, the two other areas also deserve special attention. Rio de Contas has high levels of PE, because of two endemic sister species that represent a phylogenetically isolated lineage and the Southern Espinhaço Range houses the most critically endangered species of the genus. Most endemic species of Minaria occur in vegetation islands on rocky outcrops (campos rupestres). These low-fuel areas are less susceptible to fire, suggesting that the Espinhaço Range has served as a historical refuge for fire-sensitive lineages. Our results suggest that conservation units in the Espinhaço Range cover a great proportion of the evolutionary diversity of Minaria and that fire management is probably an important strategy to preserve this endemic biodiversity.     

Richness and endemism in Asclepiadoideae (Apocynaceae) from the Espinhaço Range of Minas Gerais, Brazil – a conservationist view

The Espinhaço Range, located in the states of Minas Gerais andBahia, has a type of vegetation with one of the highest degrees of endemism inBrazil: the campos rupestres. In this area, Asclepiadoideaeis among the most diverse angiosperm groups, including species with broaddistributions and others restricted to small areas. This study attempts toevaluate the species richness and the degree of endemism in this region, as wellas the influence of collecting efforts on the perception of biodiversity. It isbased especially on the Asclepiadoideae from the Espinhaço Range of MinasGerais (ERMG), though a brief consideration of the situation in Bahia is alsointroduced. For comparative studies, the ERMG was divided into four regions:South, Serra do Cipó, Diamantina Plateau, and North. The species werethen characterized according to their distribution and occurrence in each ofthese regions. Ninety-seven species of Asclepiadoideae are native to the ERMG;about 30% of them are endemic to this area and almost 25% are restricted to onlyone of the four regions. The Serra do Cipó and the Diamantina Plateaupresent the highest degrees of endemism, and the highest richness innumber of species is found in the South. Nevertheless, there is a progressive decrease in collectingefforts northwards, which may distort species distribution and occurrence, andlead to misinterpretations about centers of diversity and endemism. TheEspinhaço Range should be considered vulnerable in its entirety becauseof the singular flora still incompletely known and the restricted distributionof many species. Programs that establish priority areas of conservation withoutconsidering the region as a whole will only offer temporary, partial protectionfor its biodiversity.     

COLONIZATION OF THE EPINEUSTON BY CYSTODINIUM BATAVIENSE(DINOPHYCEAE): BEHAVIOR OF THE ZOOSPORE1

Cystodinium bataviense Klebs is the first dinoflagellate observed to exhibit specialized zoospore behavior which results in colonization of the epineuston. The zoospore: (1) is strongly phototactic; (2) changes shape rapidly upon release; (3) possesses at least two types of swimming behavior, including a “stop mechanism”; and, (4) sheds its theca as the new cell wall asymmetrically elongates into the immobile vegetative stage. These features working in concert facilitate the entrance of Cystodinium into the epineuston. Detailed observations of zoospore morphology and analysis of its behavior are used as new characters to further delimit C. bataviense. Since vegetative morphology has proven unsatisfactory in circumscribing other Cystodinium species, the study of variation in zoospore characters will help to clarify taxonomic units within the genus.     

Character intercorrelation and the potential role of phenotypic plasticity in orchids: a case study of the epiphyte Liparis resupinata

Character intercorrelation was studied in a natural population of the epiphytic orchid Liparis resupinata in northern Thailand, and patterns of morphological variation in relation to the local growth environment of individual plants were mapped. Massive occurrence of character intercorrelation was detected, but clone size only influenced few characters of individual flowering shoots. Variation in vegetative and floral organs was largely independent, but two cases differed from the general pattern: (1) the only character not defined by size (distance between apices of lateral sepals) exhibited largely independent variation; (2) ovary length was positively correlated with nearly all other characters. Major groups of vegetative and floral characters were found to covary with different combinations of ecological parameters. Although our study does not document the existence of phenotypic plasticity in L. resupinata, the overall patterns observed would be congruent with a scenario involving phenotypic plasticity. No positive correlation between variability and apparent morphological susceptibility to environmental influence was found; but floral characters were generally less variable and covaried with more ecological parameters than vegetative characters. Based on our observations, we make a few methodological recommendations for morphometric studies of species complexes.     

Natural hybrids in Chamaecrista sect. Absus subsect. Baseophyllum (Leguminosae-Caesalpinioideae): genetic and morphological evidence

Summary Chamaecrista sect. Absus subsect. Baseophyllum (Leguminosae–Caesalpinioideae) includes eight species with geographic distribution concentrated in the Cadeia do Espinha?o mountain range of the States of Bahia and Minas Gerais, in eastern Brazil. During the taxonomic revision of this group, individuals were encountered with intermediate morphology between three sympatric species. Allozyme and multivariate morphometric analyses were carried out to investigate the occurrence of hybridization between these species in four populations and 14 suspected hybrid individuals between C. confertiformis and C. depauperata and between C. blanchetii and C. confertiformis. The results of both analyses support the occurrence of natural hybridization between them, and that all the individuals with intermediate morphology are probably F1 hybrids. The hybrids are formally described as C. × blanchetiformis and C. ×patyensis.