RESUMEN

Abstract Canga is an environment of great natural and economic value because it harbours a considerable number of endemic species on a substrate that is rich in iron ore. In the Amazon, this open vegetation type grows on top of isolated outcrops in a dense forest matrix found in the Carajás region, in southeastern Pará. Of these outcrops, the Parque Nacional dos Campos Ferruginosos (PNCF) is the only area of Amazonian canga with a strict protection status. Therefore, industrial activity in the region needs to implement mitigation actions to ensure species and habitat conservation. The objective of this study is to complement and review the floristic list of this recently created protected area, enabling us to compare the floristic similarity between it and other 14 Amazonian canga outcrops found outside the conservation units of full protection in the region. This data provides a basis to understand the floristic and phylogenetic complementarity of those patches to support conservation action. For this, six field trips were carried out in the Serra da Bocaina and two in the Serra do Tarzan, respectively, in order to increase the sampling efforts in PNCF and to obtain a more comprehensive plant list. Floristic composition was investigated using multivariate analyses (non-metric multidimensional scaling and unweighted pair group method with arithmetic mean) and phylogenetic structure across studied areas. We added 159 species to the floristic list of the PNCF and the results of the analyses showed that all 16 areas (n.b. PNCF comprises two of these sites) have an overall floristic similarity of 42%, with the least similar areas at 35% and the most similar at 50%. The different micro-habitats found in each study site highlight the high beta diversity of the Amazonian canga sites, making each area unique. Therefore, even if the Parque Nacional dos Campos Ferruginosos does not harbour all the species found in the other Amazonian canga sites, it is strategic for the conservation of the vegetation on ferruginous outcrops in the Amazon, protecting its biodiversity, different habitats, and associated ecosystem services.

Resumo Canga é um ambiente de grande valor natural e econômico por abrigar um número considerável de espécies endêmicas sobre substrato rico em minério de ferro. Na Amazônia, esse tipo de vegetação aberta cresce sobre afloramentos isolados em uma matriz de floresta densa encontrada na região de Carajás, no sudeste do Pará. Dentre esses afloramentos, o Parque Nacional dos Campos Ferruginosos (PNCF) é a única área de canga Amazônica que apresenta o status de proteção integral permanente. Dessa forma, a atividade industrial presente na região necessita implementar ações de mitigação para assegurar a conservação de espécies e habitats relacionados às cangas. O objetivo deste estudo é complementar e revisar a lista florística dessa área protegida, recentemente criada, permitindo comparar a sua similaridade florística com outros 14 afloramentos de cangas Amazônicas localizados fora de unidades de conservação de proteção integral encontradas na região. Tais dados fornecem subsídio para entender a complementaridade florística e filogenética desses fragmentos para apoiar ações de conservação. Para isso, foram realizadas seis viagens de coleta à Serra da Bocaina e à Serra do Tarzan, respectivamente, para aumentar o esforço amostral no PNCF e obter uma lista de plantas mais abrangente. A composição florística foi investigada por meio de análises multivariadas (non-metric multidimensional scaling and unweighted pair group method with arithmetic mean) e estrutura filogenética nas áreas estudadas. Nós adicionamos 159 espécies na lista florística do PNCF e os resultados das análises demonstraram que todas as 16 áreas (n.b. o PNCF compreende duas dessas áreas) têm uma similaridade florística total de 42%, com áreas menos similares de 35% e as mais similares de 50%. Os micro-habitats encontrados em cada área de estudo evidenciam a alta diversidade beta das áreas de cangas Amazônicas, o que as tornam únicas. Portanto, ainda que o Parque Nacional dos Campos Ferruginosos não abrigue todas as espécies encontradas em outras áreas de cangas Amazônicas, ele é estratégico para a conservação dos afloramentos ferruginosos na Amazônia, protegendo a sua biodiversidade, os diferentes habitats e os serviços ecossistêmicos associados.

RESUMEN

Inselbergs are azonal formations found scattered in different biomes globally. The first floristic list focusing on an inselberg in the Brazilian Amazon is presented here. We aimed to investigate floristic and phylogenetic connections among Neotropical inselbergs and analyze whether environmental variables act as a filter of plant lineages. We used a database compiled from 50 sites spanning three main Neotropical biomes (Amazon, 11 sites, Atlantic Forest, 14 sites, and Caatinga, 25 sites) comprising 2270 Angiosperm species. Our data highlight the vastly different inselberg flora found in each biome. The inselberg floras of the Atlantic Forest and Caatinga show closer phylogenetic ties than those seen in the other biome pairs. The phylogenetic lineages found in all three biomes are also strongly divergent, even within plant families. The dissimilarity between biomes suggests that distinct biogeographical histories might have unfolded even under comparable environmental filtering. Our data suggest that the inselberg flora is more related to the biome where it is located than to other factors, even when the microclimatic conditions in the outcrops differ strongly from those of the surrounding matrix. Relative to the other biomes, the flora of the Caatinga inselbergs has the highest level of species turnover. There is a possibility that plants colonized these rather distant inselbergs even when they were found under very different climatic conditions than those in the Amazonian and Atlantic Forest biomes. It is worth noting that none of the studied inselbergs found in the Caatinga biome is protected. In view of the uniqueness and drought-resilient lineages present in each group of inselbergs, along with their vulnerability to destruction or disturbance and their strong connection with water availability, we stress the need to protect this ecosystem not only to conserve plants potentially useful for ecological restoration but also to preserve the balance of this ecosystem and its connections.

Asunto(s)

RESUMEN

PREMISE: There is little direct evidence linking floral development and pollination biology in plants. We characterize both aspects in plain and ornamented flowers of Trimezieae (Iridaceae) to investigate how changes in floral ontogeny may affect their interactions with pollinators through time. METHODS: We examined floral ontogeny in 11 species and documented pollination biology in five species displaying a wide range of floral morphologies. We coded and reconstructed ancestral states of flower types over the tribal phylogeny to estimate the frequency of transition between different floral types. RESULTS: All Trimezieae flowers are similar in early floral development, but ornamented flowers have additional ontogenetic steps compared with plain flowers, indicating heterochrony. Ornamented flowers have a hinge pollination mechanism (newly described here) and attract more pollinator guilds, while plain flowers offer less variety of resources for a shorter time. Although the ornamented condition is plesiomorphic in this clade, shifts to plain flowers have occurred frequently and abruptly during the past 5 million years, with some subsequent reversals. CONCLUSIONS: Heterochrony has resulted in labile morphological changes during flower evolution in Trimezieae. Counterintuitively, species with plain flowers, which are endemic to the campo rupestre, are derived within the tribe and show a higher specialization than the ornamented species, with the former being visited by pollen-collecting bees only.

Asunto(s)

RESUMEN

BACKGROUND AND AIMS: The Neotropical tribe Trimezieae are taxonomically difficult. They are generally characterized by the absence of the features used to delimit their sister group Tigridieae. Delimiting the four genera that make up Trimezieae is also problematic. Previous family-level phylogenetic analyses have not examined the monophyly of the tribe or relationships within it. Reconstructing the phylogeny of Trimezieae will allow us to evaluate the status of the tribe and genera and to examine the suitability of characters traditionally used in their taxonomy. METHODS: Maximum parsimony and Bayesian phylogenetic analyses are presented for 37 species representing all four genera of Trimezieae. Analyses were based on nrITS sequences and a combined plastid dataset. Ancestral character state reconstructions were used to investigate the evolution of ten morphological characters previously considered taxonomically useful. KEY RESULTS: Analyses of nrITS and plastid datasets strongly support the monophyly of Trimezieae and recover four principal clades with varying levels of support; these clades do not correspond to the currently recognized genera. Relationships within the four clades are not consistently resolved, although the conflicting resolutions are not strongly supported in individual analyses. Ancestral character state reconstructions suggest considerable homoplasy, especially in the floral characters used to delimit Pseudotrimezia. CONCLUSIONS: The results strongly support recognition of Trimezieae as a tribe but suggest that both generic- and species-level taxonomy need revision. Further molecular analyses, with increased sampling of taxa and markers, are needed to support any revision. Such analyses will help determine the causes of discordance between the plastid and nuclear data and provide a framework for identifying potential morphological synapomorphies for infra-tribal groups. The results also suggest Trimezieae provide a promising model for evolutionary research.

Asunto(s)

RESUMEN

BACKGROUND AND AIMS: The amount of data collected previously for Velloziaceae neither clarified relationships within the family nor helped determine an appropriate classification, which has led to huge discordance among treatment by different authors. To achieve an acceptable phylogenetic result and understand the evolution and roles of characters in supporting groups, a total evidence analysis was developed which included approx. 20 % of the species and all recognized genera and sections of Velloziaceae, plus outgroups representatives of related families within Pandanales. METHODS: Analyses were undertaken with 48 species of Velloziaceae, representing all ten genera, with DNA sequences from the atpB-rbcL spacer, trnL-trnF spacer, trnL intron, trnH-psbA spacer, ITS ribosomal DNA spacers and morphology. KEY RESULTS: Four groups consistently emerge from the analyses. Persistent leaves, two phloem strands, stem cortex divided in three regions and violet tepals support Acanthochlamys as sister to Velloziaceae s.s., which are supported mainly by leaves with marginal bundles, transfusion tracheids and inflorescence without axis. Within Velloziaceae s.s., an African Xerophyta + Talbotia clade is uniquely supported by basal loculicidal capsules; an American clade, Barbacenia s.l. + Barbaceniopsis + Nanuza + Vellozia, is supported by only homoplastic characters. Barbacenia s.l. (= Aylthonia + Barbacenia + Burlemarxia + Pleurostima) is supported by a double sheath in leaf vascular bundles and a corona; Barbaceniopsis + Nanuza + Vellozia is not supported by an unambiguous character, but Barbaceniopsis is supported by five characters, including diclinous flowers, Nanuza + Vellozia is supported mainly by horizontal stigma lobes and stem inner cortex cells with secondary walls, and Vellozia alone is supported mainly by pollen in tetrads. CONCLUSIONS: The results imply recognition of five genera (Acanthochlamys (Xerophyta (Barbacenia (Barbaceniopsis, Vellozia)))), solving the long-standing controversies among recent classifications of the family. They also suggest a Gondwanan origin for Velloziaceae, with a vicariant pattern of distribution.

Asunto(s)