Water content and GA(3)-induced embryonic cell expansion explain Euterpe edulis seed germination, rather than seed reserve mobilisation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Histochemical analysis of seed reserve mobilization in Passiflora edulis Sims fo. flavicarpa O. Deg. (yellow passion fruit) during germination

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Diet of the maned wolf (Chrysocyon brachyurus) and its role in seed dispersal on a cattle ranch in Brazil

The maned wolf Chrysocyon brachyurus is the largest canid inhabiting South America. Its geographic distribution includes the open fields of Brazil's central area, which is currently undergoing agricultural expansion. The diet of the maned wolf and its seasonal variation was determined on a dairy cattle ranch (Sao Luis farm, 566 ha) in the State of Minas Gerais, Brazil. From January to December faeces of the maned wolf were collected monthly (n = 150 scats; 397 food item occurrences). Twenty-nine taxa were identified from scats, 18 of animal origin (46% or 183 occurrences) and 11 of plants (54% or 214 occurrences). The fruits of Solanum lycocarpum were the dominant food item in our study (29%). Mammals contributed 13%, arthropods 12%, birds 11% and reptiles 2% of the food items. Arthropods and fruits were prevalent in the rainy season and mammals in the dry season. As expected for a heavily fanned region, frugivory results were at the lower end of the diversity scale (9-33 species) and included four old garden species. No previous study of the diet of maned wolf has registered as many species of Solanaceae as this one. Although dietary richness was lower, the main food items (wolf fruit, armadillos, rodents, birds) were the same as study sites in 'cerrado' and upland meadows. In this region, the open habitats occupied by the maned wolf were previously covered by Atlantic forest, suggesting that landscape modification such as cattle ranching has opened new frontiers for distribution expansion of the maned wolf. The impact of loss of dietary richness and the increase in Solanaceae on the survival of the maned wolf need to be evaluated.

Massive seed predation of Pseudobombax grandiflorum (Bombacaceae) by parakeets Brotogeris versicolurus (Psittacidae) in a forest fragment in brazil

Here we report massive seed predation of Pseudobombax grandiflorum (Bombacaceae) by Botogeris versicolurus (Psittacidae) in a forest fragment in Brazil. The intensity of seed predation was very high when compared to other studies in continuous forest, perhaps resulting from a scarcity of resources in such areas. This scarcity may limit the range of parrot's diet to a few plant species. It suggests that studies of Psittacidae seed predation may be important for conservation of some plants in fragments.

Testing the quick meal hypothesis: the effect of pulp on hoarding and seed predation of Hymenaea courbaril by red-rumped agoutis (Dasyprocta leporina)

Red-rumped agoutis (Dasyprocta leporina) are important seed dispersers/predators of Neotropical large-seeded plants. Several species of seeds cached by agoutis have an edible reward, in contrast to temperate rodent-dispersed diaspores. The quick meal hypothesis states that the presence of a reward such as edible pulp will enhance the efficiency of rodents as seed disperses by satiating the animal and, consequently, reducing seed predation and enhancing hoarding. In this study, this hypothesis was tested using as the reference system the pulp and seeds of Hymenaea courbaril. Seeds with and without pulp were offered to agoutis and the behaviour of each individual was recorded. Since the probability of predation and hoarding were complementary, we used the probability of predation. The proportion of agoutis that preyed on at least one seed was similar for seeds with (42.8% of individuals) and without (40.0% of individuals) pulp. In agoutis that preyed upon at least one seed, the probability that they killed a seed did not differ between seeds with (0.17 +/- 0.03) and without (0.20 +/- 0.08) pulp. Hence, these results do not support the 'quick meal hypothesis'.

Toward reliable estimates of seed removal by small mammals and birds in the Neotropics

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bird attributes, plant characteristics, and seed dispersal of Pera glabrata (Schott, 1858), (Euphorbiaceae) in a disturbed cerrado area

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The role of seed mass on the caching decision by agoutis, Dasyprocta leporina (Rodentia: Agoutidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The Crab-eating Fox (Cerdocyon thous) as a secondary seed disperser of Eugenia umbelliflora (Myrtaceae) in a Restinga forest of southeastern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Seed dispersal and predation in the endemic Atlantic rainforest palm Astrocaryum aculeatissimum across a gradient of seed disperser abundance

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Analysis of a hyper-diverse seed dispersal network: modularity and underlying mechanisms

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gap disturbance regime and composition in the Atlantic Montane Rain Forest: the influence of topography

In the Atlantic Montane Rain Forest of south-eastern Brazil, a field study was carried out to describe the forest disturbance regime, analyse canopy gap composition and evaluate the influence of habitat parameters on gap tree species composition. We characterized canopy gaps considering the group of variables as follows: area, type and number of tree/branch falls, topographic position, soil coverage and surrounding canopy trees. Gap composition was assessed at species level by measuring all individuals inside gaps higher than one meter. Mean gap area of the 42 canopy gaps analysed was 71.9 +/- 9.0 m(2) (mean +/- SE). Out of the studied gaps, 35.7% were created by uprooted and by snapped trees, 16.7% by dead-standing trees and 11.9% by the fall of large branches. The disturbance regime was characterized by gap openings predominantly smaller than 150 m(2) and by spatial patterning related to topography. Ridges had smaller gaps and higher proportions of gaps created by branch falls; slopes had bigger gaps generally created by uprooting events. The more abundant and frequent species were shade tolerant and the more species-rich families found inside gaps did not differ from the forest as a whole. Pioneer species were rare and restricted to medium and large size classes. The Indicator Species Analysis and the Canonical Correspondence Analysis indicated gap area, topography and the percentage of soil cover by the genera Calathea and Ctenanthe were the predominant variables correlated with woody species distribution. So, topography emerged as an important issue not only to the gap disturbance regime, but also to gap colonization. In respect to the influence of gap processes on the Atlantic Montane Rain Forest regeneration, our results support the view that canopy gap events may not be working as promoters of community wide floristic shifts.

Effects of frugivore impoverishment and seed predators on the recruitment of a keystone palm

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Factors affecting seed predation of Eriotheca gracipiles (Bombacaceae) by parakeets in a cerrado fragment

Psittacids are important pre-dispersal seed predators. However, little is known about the parameters that may determine seed predation rates by these birds, such as plants' characteristics and microhabitat. Eriotheca gracilipes (Bombacaceae) is a semi-deciduous tree widely distributed in the Brazilian cerrado. The fruits are dehiscent pods and the seeds are wind-dispersed. Some individuals lose their leaves during the fruiting season, getting very conspicuous. Here we tested the hypothesis that the absence of leaves in E. gracilipes during the fruiting season may increase pre-dispersal seed predation by psittacids. We also tested the hypotheses that (1) seed predation intensity increases with increasing plant size and (2) number of fruits, (3) seed predation decreases with the increasing number of conspecific plants in a range of 15 m, and (4) seed predation intensity is lower in plants with higher vegetation cover over their crowns. The small parakeet Brotogeris versicolurus was the only species observed preying upon the seeds of E. gracilipes. The percentage of fruits damaged by the parakeets ranged from 0 to 100% (66.98 +/- 43.11%, n = 72) among the different plants. Our data give weak support to the hypothesis that the absence of leaves may facilitate plants and/or fruits detection by the parakeets. However, seed predation intensity was significantly affected by crop size. The hypothesis that conspecific fruiting plants surrounding the studied individuals may reduce predation rate was not supported. Nevertheless, trees without higher vegetation cover over their crowns were significantly affected by increased seed predation. This suggests that seed predation by parakeets can be a potential selective factor influencing fruit crop sizes in E. gracilipes. (c) 2007 Elsevier Masson SAS. All rights reserved.

Birds and bats diverge in the qualitative and quantitative components of seed dispersal of a pioneer tree

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)