Flavio Nunes Ramos

Germinação de sementes de jenipapo: temperatura, substrato e morfologia do desenvolvimento pós-seminal

This study aimed to define the best substrate and temperature for germination of genipap (Genipa americana L. - Rubiaceae) seeds, and to describe the morphology of its seeds, post-seminal development, normal and abnormal seedlings. The experiment was designed according to a 5 x 3 factorial with constant temperatures of 20°C, 25°C, 30°C and 35°C and alternated 20°C-30°C in filter paper, vermiculite and soil substrates. The following parameters were analyzed: normal percentage germination and speed of germination. The 25°C, 30°C and 35°C temperatures and vermiculite and soil substrates were the best conditions for seed germination.

Flooding effects in seedlings of Cytharexyllum myrianthum Cham. and Genipa americana L.: responses of two neotropical lowland tree species

Six-month-old seedlings of Cytharexyllum myrianthum and Genipa americana, two common tree species in different flood-prone areas in Brazil, were flooded for up to 90 days to compare their survival and growth responses under these conditions. Seedlings of both species were found to be relatively tolerant to flooding but growth responses changed according to treatment and plant species. Growth of G. americana was reduced by flooding, showing a decrease in root and leaf dry mass, root/shoot ratio and height, without showing any adaptive morphological changes. On the other hand, growth of C. myrianthum seedlings was stimulated under flooding conditions, showing an increase in root dry mass, root/shoot ratio, height, stem diameter and some morphological changes in roots and stems, i.e., development of new roots and stem base hypertrophy. These results could be regarded as an experimental corroboration of the field observations, showing that these species could be indicated for restoration programs of some Neotropical wetlands.

Ecophysiology and morphology of seed germination of the neotropical lowland tree Genipa americana (Rubiaceae)

ABSTRACT. The morphology of Genipa americana seeds and post-seminal develop-ment was studied, and its germination response investigated in relation to storagein water, substrate water volume, osmotic potential and temperature and lightregimes. The seeds are flattened and seedlings are phaneroepigeal with leafy coty-ledons. Seeds stored in water kept viable for up to 6 mo, but germination andseedling emergence were reduced after 4 mo. Germination was not affected underwater-logged conditions, but seedling emergence was reduced at the water volumecorresponding to a water column two times deeper than the seeds’ mean thickness(70 ml). When seeds were osmotically stressed, a reduction in the rate and ger-mination percentage occurred at −0.2 MPa and germination was drastically inhib-ited at—0.6 MPa. Seeds germinated in a wide range of temperatures (15–40 °C),with optimum at continuous temperatures of 25 and 30 °C. Light was not requiredfor germination, and no dormancy mechanisms were observed. The seed and seed-ling morphology and the germinative responses of the species may permit itsregeneration in periodically flooded lowland forests and riparian habitats and areprobably key factors in explaining the species’ wide distribution.KEYWORDS: ecophysiology, flooding,

Efeito do tamanho do fragmento na dispersão de sementes de Copaíba (Copaifera langsdorffii Delf.)

Effect of fragment size on Copaifera langsdorffii seed dispersal. Habitat fragmentation may cause functional disruption in seed dispersal, if the disperser species become locally extinct in the fragments. However during the fragmentation process, there is empirical evidence of replacement of specialist by generalist species, and these generalist species could also replace the functional activity of the specialists in the ecosystem. We studied bird frugivory on C. langsdorffii in order to evaluate the patch size effect on the potential of seed dispersal of this plant. During 2008 we chose 20 focal trees distributed in five Atlantic forest remnants (range 29.2 to 104.8 ha), looking for which bird species consumed the fruits, describing their foraging behavior and consequently evaluating the potential for seed dispersal. The results suggest that there was lower similarity of bird richness among the patches. The ability to disperse seeds also varied among birds and their patterns of distribution and abundance were related with patch size. The number of good disperser species and their interactions were positively related with patch size (R2 = 0.85; p = 0.05); in contrast, the poor dispersers had the opposite tendency (R2 = 0.77; p = 0.08). Therefore the preservation of larger patch size increases the interaction events between C. langsdorffii and their good dispersers, and consequently improving their fitness.

Floral biology and breeding system of Psychotria tenuinervis Muell. Arg. (Rubiaceae) in the Atlantic rain forest, SE Brazil

(Floral biology and breeding system oi Psychotria tenuinervis Muell. Arg. (Rubiaceae) in the Atlantic rain forest, SE Brazil). The aim of this study was to investigate pollination biology, floral morphometry, morph ratio and breeding system oiPsychotria tenuinervis in an area of Atlantic rain forest in southeastern Brazil. Pollination biology was studied based on focal observations and the breeding system was determined using controlled crosses; data on flower production and floral morphometry were compared between the two floral morphs. Flower production by the two floral morphs was similar, with flowers being reciprocally herkogamous, diurnal and pollinated at similar frequencies, mainly by medium-sized bees. Corolla length and diameter, as well as anther length, were similar between the floral morphs, whereas stigma lobes were larger in thrums. Psychotria tenuinervis is a preferentially self- and intramorph-incompatible, non-apomitic species, with isoplethic populations. At the study site, P. tenuinervis may be considered as a typical distylous species, with reciprocal herkogamous flowers that favour intermorph pollinations and legitimate matings.

Reproductive Phenology, Seed Dispersal and Seed Predation in Syagrus romanzoffiana in a Highly Fragmented Landscape

The aim of this study was to evaluate Syagrus romanzoffiana (Arecaceae) (1) reproductive phenology, (2) seed dispersal and (3) seed predation in a highly fragmented landscape. Over a 24-month period, we recorded flowering and fruiting events, proportions of fallen fruit infested by insects, as well as seed dispersal and seed predation by squirrels. Overall flowering and fruiting intensities varied among months; flowering being significantly greater in January and March 2008, and fruiting in April–June and August-September 2008. There were no differences between the first and second years in the flowering and fruiting percentages, flowering and fruiting duration, their peaks or synchrony. The squirrels spent same amounts of time dispersing and eating the seeds. Additionally, there were no statistical differences among the fragments in the numbers of squirrel visits, seeds dispersed or eaten by squirrels, or in the time spent by squirrels on eating or dispersing the seeds. Seed predation rates by insects or percentage of fruits with eggs were not influenced by fruit density, size or weight. Syagrus romanzoffiana can be characterized as a robust secondary species, recommended for restoration programs in fragmented landscapes.

Functional composition and phenology of fruit-feeding butterflies in a fragmented landscape: variation of seasonality between habitat specialists

Abstract For butterflies, tolerance to the matrix may be an important criterion of habitat occurrence in fragmented landscapes. Here we examine the relative effects of habitat fragmentation and the surrounding agricultural matrix on the functional composition of fruit-feeding butterflies of the Atlantic rain forest in southeastern Brazil. Generalized linear models were used to detect the effects of landscape metrics on butterfly richness and abundance of the total assemblage and functional groups. Circular statistics were used to analyze the patterns of monthly abundance of the total assemblage and functional groups in the forest remnants and the surrounding matrices. In total, 650 butterflies representing 57 species were captured; species composition differed significantly between the forest fragments and the surrounding matrices. We recorded 22 forest specialists, 18 matrix specialists, 11 common species with matrix preference and six common species with forest preference. Forest connectivity favored the richness of forest specialists, while habitat fragmentation enhances the richness and abundance of matrix-tolerant species. Circular analysis revealed that forest specialists were more abundant in the rainy season while matrix-tolerant species proliferated in the dry season. Although maintaining connectivity of forest fragments may increase the mobility and dispersion of forest species, our results showed that landscape fragmentation modify butterfly assemblage by promoting an increase of matrix tolerant species with detriment of forest specialists.

Are biotic and abiotic factors and seedling mechanical damage in forest-edge fragments always different from the interior?

Theregenerationoffragmentsandadjacentlandscapedependson,amongothersfactors,seedlingestablishment, both in the interior and at the edge. This work considers differences between the edge and fragment interior in (1) environmental descriptors (canopy openness, temperature, soil moisture, bamboo and liana coverage and litterfall), (2) the total number of seedlings damaged and (3) the type of seedling damage. The present study was carried out in four Atlanticforestfragmentsinsouth-easternBrazil.Environmentaldescriptorsandartificialseedlingdamageweremeasuredin 10plots,10 � 10meach,ineachforestfragment,i.e. fiveattheedgesand fiveintheinterior.Litterfallwasthemaincauseof seedling damage in the present study. Bamboo and liana coverage, litterfall, soil moisture, canopy openness, minimal and maximal temperature and temperature amplitude, as well as the type and quantity of damage did not differ between the edge and the fragment interior. Temperature, however, was higher in the interior than in the edge fragments. The lack of difference between the edge and interior fragments was probably due to the reduced size of the remnants of the Atlantic forest studied, resulting from an intense internal anthropogenic impact on them and the early onset of this landscape fragmentation, which is quite old (~200 years).

Anthropogenic Matrices Favor Homogenization of Tree Reproductive Functions in a Highly Fragmented Landscape

Species homogenization or floristic differentiation are two possible consequences of the fragmentation process in plant communities. Despite the few studies, it seems clear that fragments with low forest cover inserted in anthropogenic matrices are more likely to experience floristic homogenization. However, the homogenization process has two other components, genetic and functional, which have not been investigated. The purpose of this study was to verify whether there was homogenization of tree reproductive functions in a fragmented landscape and, if found, to determine how the process was influenced by landscape composition. The study was conducted in eight fragments in southwest Brazil. The study was conducted in eight fragments in southwestern Brazil. In each fragment, all individual trees were sampled that had a diameter at breast height ≥3 cm, in ten plots (0.2 ha) and, classified within 26 reproductive functional types (RFTs). The process of functional homogenization was evaluated using additive partitioning of diversity. Additionally, the effect of landscape composition on functional diversity and on the number of individuals within each RFT was evaluated using a generalized linear mixed model. appeared to be in a process of functional homogenization (dominance of RFTs, alpha diversity lower than expected by chance and and low beta diversity). More than 50% of the RFTs and the functional diversity were affected by the landscape parameters. In general, the percentage of forest cover has a positive effect on RFTs while the percentage of coffee matrix has a negative one. The process of functional homogenization has serious consequences for biodiversity conservation because some functions may disappear that, in the long term, would threaten the fragments. This study contributes to a better understanding of how landscape changes affect the functional diversity, abundance of individuals in RFTs and the process of functional homogenization, as well as how to manage fragmented landscapes.

Demographic parameters of Akodon montensis (Mammalia: Rodentia) in an Atlantic Forest remnant of Southeastern Brazil.

Abstract Small mammals seem to be affected by edge effects, hence understanding the local dynamics of these populations is important to assess the risks to which they are exposed. The objective of this study was to compare population size, sex ratio and home range size of the rodent Akodon montensis (Cricetidae) between the edge and interior of an Atlantic Forest fragment in the dry (June-August) and rainy (December-February) seasons. The population was sampled using capture-mark-recapture methods and a spool-and-line device was used to map the movements. The population size was significantly higher in the rainy season relative to the dry season, and this pattern can be related to the higher food availability in this period, as observed in other studies. However, there was no difference in the number of individuals captured in the edge and interior. The home range size showed no significant differences between edge and interior and between males and females, although, in a general way, the females showed a greater home range size related to the males. The absence of differences between edge and interior could result from the small size of the remnants and extrapolation of edge conditions to the interior.