Rainforest In Southeastern Brazil Research Articles

Impact of tree isolation on arboreal and ground ant communities in cleared pasture in the Atlantic rain forest region of Bahia, Brazil

Summary. The Atlantic rain forest of south-eastern Brazil has been substantially cleared, resulting in the creation of a fragmented landscape. In addition to the small fragments of forest that remain, the pasture is often scattered with isolated trees. This paper investigates the capacity of these isolated trees to support representatives of the original Atlantic rain forest ant communities and also how these arboreal ants interact with the disturbance-associated ant fauna of the pasture beneath them. Twenty trees in the grassland, representing a range of distances from the forest, and 10 trees within the forest, were selected for sampling. Arboreal ants were sampled by hand collection and chemical knockdown, while the ants on the ground beneath were sampled by pitfall traps and Winkler sacks. Pasture trees supported a moderately high richness of arboreal ant species. The richness of ants on pasture trees appears to be independent of distance from forest, although this might become a significant factor on trees that are more isolated than those studied here. Ant species richness on pasture trees is higher if the trees are large, support a high epiphyte load and are native to the area. Isolated trees within the agricultural matrix therefore play some role in conserving elements of the original forest ant fauna. Since some of the species on pasture trees have been observed to reach dominant or sub-dominant status in nearby forest and cocoa farms, they may play some role in limiting pest outbreaks in the pasture close to the trees. If this is so, there may be a case for retaining an adequate density of trees to enable the influence of arboreal ants to extend over as much pasture as possible.

Bat-pollinated Flower Assemblages and Bat Visitors at Two Atlantic Forest Sites in Brazil

A comparison between bat-pollinated plant assemblages at two sites in different altitudinal ranges covered by the Atlantic rainforest in southeastern Brazil is presented. The lowlands (5–90 m) harbour ten plant species in seven families, pollinated mostly by three glossophagine bat species. The highlands (1540–1600 m) harbour seven plant species in five families, pollinated by a single species of glossophagine. Bromeliads account for about 30% of the bat-pollinated species at each assemblage. Tube and brush shapes prevail in the flowers at both sites. Corolla lengths averaged 26.8 and 37.2 mm, sugar concentrations in nectar averaged 15.0 and 18.1%, and nectar volumes averaged 150.8 and 167.0 μl in the lowland and highland assemblages, respectively. The flowers are pollinated mostly by glossophagine bats during hovering visits, and the plants are visited in the trap-line foraging pattern. The plants bloom annually and both assemblages show a staggered continual flowering pattern. Flowering seasonality was found at both sites, with flowering clustering in the drier season at the lowland site and in the wetter season at the highland site. The ratio between bat-pollinated and hummingbird-pollinated species is 0.24 at the lowland site and 0.23 at the highland one. These similar values indicate that additional studies on bat- and bird-pollinated assemblages are merited at other Atlantic rainforest sites.

A New Species of Ditassa (Asclepiadaceae) from Espírito Santo, Brazil

Ditassa oberdanii, a new species of Asclepiadaceae from remnant patches of Atlantic rainforest in Espirito Santo state, southeastern Brazil, is described, illustrated, and compared to D. oxyphylla Turczaninow, a similar species that is found in Brazil, Colombia, and Venezuela. A survey of the Asclepiadaceae of Espirito Santo, Brazil, turned up 44 species belonging to 16 genera. The largest genus is Ditassa with 11 species, including D. oberdanii. This species is found in remnant patches of lower montane rainforest in southeastern Brazil, in the Atlantic forest biome which is seriously threatened by human activities. Ditassa oberdanii Fontella & Alvarez, sp. nov. TYPE: Brazil. Espfrito Santo: Santa Teresa, Rio Saltinho, 500 m, 26 Apr. 1984, Pizziolo 22 (holotype, MBML; isotype, HB). Figure 1. Species nova D. oxyphyllae Turczaninow affinis, sed imprimis foliis linear-lanceolatis angustioribus, corollae lobis extus glabris et longioribus, caudiculis non geniculatis, polliniis ellipticis vel subellipticis et latioribus differt. Vines; stems hirsute-tomentose. Leaves with flattened petioles, hirsute above, glabrescent beneath, 7-10 mm long; blade linear-lanceolate, glabrous to glabrescent with secondary nerves rectilinear, base cuneate with two glands at petiole juncture, apex acuminate, 61-69 X 10-13 mm. Inflorescence an umbelliform cyme, extra-axillary, 3-6-flowered; peduncles hirsute-tomentose, 1-2 mm. Flowers white; pedicels hirsute, 2-4 mm long. Calyx deeply lobed; lobes ovate-lanceolate, hirsute outside, glabrous inside, margins hyaline, 2-2.5 X 1-1.5 mm, with 1-2 minute inside glands at base of each sinus; corolla subcampanulate; tube glabrous outside, pubescent inside, 0.8-1.0 mm long; lobes linear-lanceolate, glabrous outside, pubescent inside on upper half at margin, with longer hairs at apex, 4-5 X 1-1.3 mm. Corona lobes filiform, twice the length of the gynostegium, upper part papillose, the outer 3-3.2 X 0.1-0.3 mm, apex slightly curved, the inner 3.5-4 X 0.2-0.3 mm, apex curving inward. Anthers rectangular or subrectangular, ca. 0.75 x 0.57 mm, appendages membranaceous, suborbicular, ca. 0.42 mm long. Corpusculum ovate, 0.20-0.22 x 0.08-0.09 mm; translator arms filiform, 0.06-0.09 mm long; pollinia elliptic or subelliptic, longer than corpusculum, slightly curved, 0.24-0.28 x 0.09-0.17 mm. Stigmatic appendix apiculate. This new species is related to Ditassa oxyphylla Turczaninow, from which it differs mainly by the linear-lanceolate leaves, longer corolla lobes (4-5 mm), which are glabrous outside, straighter translator arms, and wider (0.09-0.17 mm), elliptic to subelliptic pollinia. In contrast, D. oxyphylla has ovate-lanceolate to elliptic leaves, corolla lobes 23 mm long, geniculate translator arms, and oblong to subclavate pollinia (0.06-0.08 mm wide). Ditassa oxyphylla is found in Colombia, Venezuela, and Brazil, where it occurs in Pernambuco, Alagoas, and Bahia states; in Bahia it is found in caatinga, remnant liana forest (Mata de Cip6) and pastures, from 500-600 m above sea level (Pereira & Silva, 1973; Pereira et al., 1989). Ditassa oberdanii is named in honor of Oberdan Jose Pereira, Professor of Botany at the Espirito Santo Federal University (UFES), who has contributed greatly to the study of the flora of Espirito Santo, Brazil. Acknowledgments. We thank the CNPq for Jorge Fontella-Pereira's research fellowship, the curators of R, RB, GUA, MBML, VIES, and CVRD, Dorothy Sue Dunn de Araujo for the translation of the text into English, and Gloria Gongalves for the sketch.

Plant establishment on flooded and unflooded patches of a freshwater swamp forest in southeastern Brazil

ABSTRACTPlant establishment was studied in a swamp forest in the lowland Atlantic rainforest in southeastern Brazil. A topographic gradient allowed a clear distinction between a periodically flooded and a permanently flooded site in the study area. Both sites were mosaics of patches: the former showed soil patches of varying sizes subject to distinct flooding durations (from 0 to 300 d per year) and in the latter, the tank bromeliads which densely occupied the understorey, trap litter and provided ‘suspended soil’ patches. In the periodically flooded site, the occurrence of regenerants (< 1.0 m tall) of the actively regenerating tree populations of Calophyllum brasiliense, Symphonia globulifera and Tovomitopsis paniculata (all Clusiaceae), originating from seed or vegetative organs, was recorded for 1 m2 quadrats placed in flooded (n = 82) and unflooded (n = 103) patches. In the permanently flooded site, dominated by Tabebuia cassinoides (Bignoniaceae), the presence of germinated seedlings was counted for 400 rosettes of the terrestrial tank bromeliad Nidularium procerum. The results showed that unflooded patches, including tank bromeliads, favoured seedling establishment. However, T. paniculata and T. cassinoides colonize patches where flooding lasts longer or is permanent mostly by reproducing vegetatively, while the seeds of C. brasiliense, which showed no form of vegetative reproduction, and S. globulifera are successful in colonizing flooded patches. Germination tests and field observations indicated that, for C. brasiliense, pre- and post-dispersal seed dormancy, a two-phase seed dispersal (water and bats) and seedling tolerance to flooding accounted for this pattern.

Reproductive Biology of the Distylous Manettia luteo‐rubra (Rubiaceae)

AbstractThe reproductive biology of Manettia luteo‐rubra was studied in the coastal montane Atlantic rain forest of southeastern Brazil. This Rubiaceae is a perennial vine that flowers all the year round, but has a flowering peak during the dry season. It presents reciprocal herkogamy, thus the plants are morphologically distylous. The morphs occur in a 1:1 ratio, and pollen diameter and corolla length vary between short and long‐styled flowers. Manettia luteo‐rubra displays typical heterostylous self‐incompatibility and sets almost no fruits from self‐ or intramorph pollinations. The flowers are tubular, red with yellow lobes, and odourless. Anthesis is asynchronous, and the flowers last about four days. Concentration of sugars in nectar is similar in both morphs, ca. 24%, this concentration being typical for hummingbird flowers. Three species of hummingbirds are the major pollinators of the flowers of M. luteo‐rubra at the study site: the hermits Phaethornis eurynome and P. squalidus, and the trochiline Thalurania glaucopis. Three species of Heliconius butterflies act as minor pollinators. Both morphs of M. luteo‐rubra exhibit natural fruit‐set of about 80%, this reproductive output being maintained throughout the year by the pollinators' constancy to the flowers.

The Saw-billed HermitRamphodon naevius and its flowers in southeastern Brazil

The large Saw-billed HermitRamphodon naevius and its foraging behaviour on a variety of ornithophilous flowers were studied at one site in the Atlantic rainforest in southeastern Brazil. The flower assemblage visited by this endemic hermit throughout the year is composed mainly by epiphytes and herbs, Bromeliaceae and Heliconiaceae being the staple foodplants. Most of the plant species present steady-state, long-tubed and high-reward flowers, and bloom sequentially. The Saw-billed Hermit is a year-round resident and traplining forager, behaves aggressively over its feeding routes, and excludes conspecifics and other hummingbird species from its main flower sources. This large hermit regularly visited and pollinated about 45 % of the native ornithophilous plants at the study site, thus acting as the major pollinator on this flower assemblage.

Orchids of the High Mountain Atlantic Rain Forest in Southeastern Brazil.

Orchids of the High Mountain Atlantic Rain Forest in Southeastern Brazil.

Pollination of three species of Abutilon (Malvaceae) intermediate between bat and hummingbird flower syndromes

Some species of Abutilon in southeastern Brazil overlap their flower features between hummingbird and bat pollination syndromes. We studied three such species in the montane rainforest in southeastern Brazil. Abutilon rufinerve , A. regnellii and A. aff. regnellii present the following combination of ornithophilous and chiropterophilous features: bell to bowl-shaped flowers lasting about 30 h, coloured pinkish to purplish, or yellowish, crepuscular (dusk or dawn) anthesis, and very faint cabbage odour. The flowers are visited and pollinated by a species of phyllostomid bat at night, and by several species of hummingbirds during the day. Although somewhat intermediate between ornithophily and chiropterophily, the floral features of the three species of Abutilon tend towards the bat-pollination syndrome.

The Bizarre Inflorescence of Norantea brasiliensis (Marcgraviaceae): Visits of Hovering and Perching Birds1

AbstractThe pollination biology of Norantea brasiliensis (Marcgraviaceae) was studied in the rain forest of southeastern Brazil. This plant presents bizarre, brush‐type racemous inflorescences bearing numerous flowers and extrafloral cup‐shaped nectaries. Flower anthesis is diurnal, nectar production is continuous and copious, and the sticky pollen is readily removed by visitors during the first morning hours. The ruby‐coloured inflorescences were visited by eight species of hummingbirds (Trochilidae), and 10 species of passerine birds (three Coerebidae and seven Thraupidae). Hummingbirds hovered while probing for nectar and touched flowers occasionally, whereas passerine birds perched and made contact with flowers habitually. Due to differences in flower‐visiting and general foraging behaviour, perching birds act as better pollen vectors than hovering birds. The inflorescence of Norantea brasiliensis seems well fitted for pollination by passerine birds, and the hexose‐dominated nectar supports this idea. Pollination syndrome trends within Marcgraviaceae may stem from insect‐pollinated, condensed and spike‐like inflorescences which would give rise to bird‐pollinated, brush‐type inflorescences. From the same basic condensed inflorescence, bat‐pollinated umbelliform inflorescence may be derived from bird‐pollinated, pendulous and corymb‐like inflorescences. These postulated inflorescence types are found among the extant species of Marcgraviaceae.