Maria Regina de Vasconcellos Barbosa

Composição florística e análise fitossociológica do componente arbustivo-arbóreo de um remanescente florestal no Agreste Paraibano

A floristic and phytosociological survey was conducted in a caatinga area in the Agreste (sub-humid) region of Paraiba state. All trees and shrubs ³ taller than 1m and larger than ³ 3cm stem diameter found in 30 plots, 10x20m each, were identified and measured. Standing dead plants were also included. A total of 1952 plants were registered, belonging to 22 families, 38 genera and 54 species. Families with most species were Mimosaceae (6 species), Euphorbiaceae (6), Caesalpiniaceae (5), and Rubiaceae (5). Total plant density and stem basal area were 3253 plant ha-1 and 34.77m2 ha-1. Maximum diameter and height were 63cm and 15m. About half of the plants (45.7%) had a stem diameter between 3 and 6cm. Thiloa glaucocarpa (Mart.) Eichl. was the most important species (highest IVI value). The flora included mostly species already registered in other caatinga areas but also species which are typical from more mesic formations, specially the humid forests of high altitudes in Northeast Brazil.

Flora Paraibana: Annonaceae Juss

The objective of this study is to carry out a taxonomic treatment of the family Annonaceae for the Flora of Paraiba Project. Collections were made throughout Paraiba. In addition, specimens were studied from the following herbaria: JPB, EAN and IPA. The material available was identified using analytical keys, botanical literature, and photographs of type specimens. The descriptions and illustrations are based on living material or herbarium specimens. Six genera of Annonaceae, comprising a total of 15 species were found in Paraiba: Anaxagorea (1), Annona (6), Duguetia (2), Guatteria (2), Rollinia (2) and Xylopia (2), with 11 new records for the state.

A família Rubiaceae na Reserva Biológica Guaribas, Paraíba, Brasil: subfamílias Antirheoideae, Cinchonoideae e Ixoroideae

This paper is a survey of Rubiaceae subfamilies Antirheoideae, Cinchonoideae and Ixoroideae in the Guaribas Biological Reserve, Paraiba, Brazil. Intensive collections were made from October/2000 to October/2001. Twelve species, 10 genera and five tribes were recognized. The most diverse subfamily was Antirheoideae, with five species, four genera and two tribes. The genera with the most species were Guettarda L. (2) and Tocoyena Aubl. (2). Alibertia A. Rich. ex DC., Alseis Schott, Chiococca P. Browne, Chomelia Jacq., Coutarea Aubl., Posoqueria Aubl., Sabicea Aubl., and Salzmannia DC. were represented by only one species each. Keys, descriptions, comments on morphology and species distributions, as well as illustrations of the taxa are provided.

A família Rubiaceae na Reserva Biológica Guaribas, Paraíba, Brasil: subfamília Rubioideae

Este trabalho consiste no levantamento dos representantes de Rubiaceae subfamilia Rubioideae na Reserva Biologica Guaribas, Estado da Paraiba, Brasil. Foram realizadas coletas intensivas no periodo de outubro/2000 a outubro/2001, as quais resultaram em 17 especies e nove generos de Rubioideae. Os generos com maior numero de especies foram Psychotria L. (seis) e BorreriaG. Mey. (quatro). Coccocypselum P. Browne, Declieuxia Kunth, Diodia L., Mitracarpus Zucc. ex Roem. & Schult., PalicoureaAubl., RichardiaL. e Staelia Cham. & Schltdl. apresentaram uma unica especie cada. Perama hirsuta Aubl., de posicao taxonomica incerta na familia, tambem foi tratada neste trabalho. Sao apresentados chave, descricoes, comentarios e ilustracoes dos taxons.

Nitrogen isotopic patterns in tropical forests along a rainfall gradient in Northeast Brazil

Background and aimsThe interpretation of ecosystem nitrogen isotopic patterns is subject to controversies since there are few surveys of signals along climate gradients within the same region. We determined the effects of a rainfall gradient, under high temperatures, on the soil and plant δ15N signals in Northeast Brazil.MethodsNitrogen, carbon and δ15N signals were determined from coastal perennial to subhumid and semiarid deciduous forests to savanna – deciduous forest transition.ResultsSoil C and N concentrations were linearly related and both related quadratically with mean annual rainfall while δ15N concentrations decreased with higher rainfall (16 to 4‰). Plant δ15N was 1–3‰ lower than soil δ15N (Δδ15N) in all areas. Only in the deciduous forests, leaves of target species had significantly lower 15 N signals than those of non-fixing species, allowing estimation of fixation.ConclusionsIn the perennial forests the low signals indicated that the 15 N natural abundance method was not suitable to estimate fixation, while in the savanna – deciduous forest transition, high signals indicated that the legume species were not fixing. The smaller Δδ15N than those reported in cooler areas and the absence of rainfall effect indicates that, when high, temperature overrides the rainfall effect.

From evergreen to deciduous tropical forests: how energy–water balance, temperature, and space influence the tree species composition in a high diversity region

Background: Understanding floristic and geographic patterns in one of the most biodiverse regions in the world – the Atlantic forest of eastern Bahia, Brazil – can identify the drivers of diversity in tropical forests and provide useful information for biological conservation. Aims: To understand the role of both climate and geographical location on variation in tree species composition in a region characterised by an abrupt transition from wet forests to semi-arid thorn-woodlands. To test whether a regional classification of forests according to elevation belts and leaf flush pattern is consistent with floristic composition. Methods: We submitted 14,094 tree species occurrence records and 31 geo-climatic variables prepared for 57 sites in eastern Bahia, Brazil, to multivariate and regression analyses and variance partitioning. Results: Climate and space were both significantly (P ≤ 0.05) contributing to explaining floristic variations. Actual evapotranspiration, duration of water deficit, and minimum temperature of coldest month were the main predictors. Floristic differences were significant except when comparing evergreen lower plains and upper plains forests. Conclusions: Although distance among sites may play an important role, species composition is chiefly influenced by environmental gradients. This highlights environmental heterogeneity as a key factor in the planning of biodiversity conservation in tropical forests.

Passerine phenology in the largest tropical dry forest of South America: effects of climate and resource availability

ABSTRACT In tropical dry areas, rainfall is predicted to be the most important climatic variable influencing bird phenology because it triggers food and foliage production. In addition, because resources are scarce, the moulting and breeding seasons are not expected to overlap. We conducted a 2-year study on the phenology of passerine birds at one site in Caatinga, South America’s largest dry forest region to: (a) evaluate the contributions of climate, foliage cover, and food abundance to the onset of the breeding and moulting seasons, (b) assess the duration of the breeding and moulting seasons, and (c) measure the frequency of the bird moult–breeding overlap. Birds can use rainfall or humidity as environmental cues to start their breeding seasons. The effects of water availability are mediated by both foliage cover and food abundance, but foliage cover is more important to the onset of the bird breeding season than food abundance. In contrast, both foliage cover and food abundance equally influence the timing of the primary moult. Because we found several cases of moult–breeding overlap, we suggest that some passerine species adapt that strategy to adjust the timing of their life history stages to the relatively short period of abundant resource availability.

Uma nova espécie de Coussarea Aubl. (Rubiaceae) para a mata atlântica no estado da Bahia, Brasil

A new species, Coussarea andrei M.S. Pereira & M.R. Barbosa, collected in Atlantic Forest remnants in Bahia, Brazil, is described and illustrated. It is close to Coussarea nodosa (Benth.) Mull. Arg., differing in the elliptical leaves, peduncle over 2.5 cm long, non-umbelliform thyrse, hypocrateriform corolla and epicarp golden-brownish when ripe.

Eumachia expanded, a pantropical genus distinct from Psychotria (Rubiaceae, Palicoureeae)

Abstract Taylor, C.M., S.G. Razafimandimbison, L. Barrabé, J.G. Jardim & M.R.V. Barbosa (2017). Eumachia expanded, a pantropical genus distinct from Psychotria (Rubiaceae, Palicoureeae). Candollea 72 : 289–318. In English, English abstract. The pantropical genus Margaritopsis C. Wright (Rubiaceae, Palicoureeae) was recently separated from Psychotria L. and transferred to a different tribe, Palicoureeae, based on both molecular and morphological data. Margaritopsis has been studied in the Neotropics, and in Africa as Chazaliella E.M.A. Petit & Verdc.; the species that belong to this group in the Pacific are enumerated for the first time here. Recently Eumachia DC. was found to be an older name for this group, and a few species of Margaritopsis have been transferred nomenclaturally to that genus. Here Eumachia is surveyed comprehensively for the first time, with a list of species and an overview of morphological characteristics. The remaining species of Margaritopsis are nomenclaturally transferred here to Eumachia, along with one species of Hodgkinsonia F. Müll., one species of Mapouria Aubl., and several species of Psychotria from Asia, Australia, New Guinea, and the Pacific region. In this new circumscription Eumachia includes 83 species, and is characterized within Palicoureeae by a yellowish green drying color; stipules that are persistent or fall by fragmentation and are generally glandular when young and hardened when old; green to whitened inflorescence axes; white to cream or yellowish green, often rather small corollas; orange to red fruits; pyrenes with marginal pre-formed germination slits and no ethanol-soluble pigments; and non-ruminate endosperm. Eumachia includes 20 species, 8 subspecies, and 7 varieties in Africa, 27 species in the Neotropics, and 36 species and 6 varieties in Asia, Australasia, and the Pacific region. Here we publish 81 new nomenclatural combinations in Eumachia and two new synonymies for Neotropical names, and 11 names from various regions are lectotypified. Received: March 15, 2017; Accepted: June 14, 2017; First published online: July 20, 2017

First record of Chomelia triflora (J.H. Kirkbr.) Delprete & Achille (Rubiaceae) from Brazil

This paper presents the first record of Chomelia triflora from Brazil, to date a species only known from French Guiana. After examining herbaria collections and doing fieldwork in the Brazilian Amazon, we found that the species also occurs in and around the Ducke Reserve in the state of Amazonas, Brazil. Our finding increases the data about the Brazilian Amazon and contributes to the better knowledge of Chomelia in Brazil.