Search

The plant species of the Caatinga biome are food sources of great importance for herds. Goat farming is one of the most explored agricultural activities in the Northeast region of Brazil, where goats are important seed dispersers in semiarid areas. In this study, we evaluate the passage of seeds of four Caatinga forest species through goats' digestive system, their recovery, and the effect on seed germination (Ger). A completely randomized experimental design was used. The seeds of four species Piptadenia stipulacea, Mimosa tenuiflora, Desmanthus virgatus, and Mimosa caesalpiniifolia were provided to eight goats and evaluated after nine excretion periods (12, 24, 36, 48, 60, 72, 84, 96, and 108 h). Seed recovery was low, with values of 10.87% for M. tenuiflora, 3.41% for P. stipulacea, 2.04% for M. caesalpiniifolia, and 1.54% for D. virgatus. The seeds of D. virgatus and M. tenuiflora are small and pass faster through goats' digestive system, with the largest amount recovered 48 h after ingestion. In contrast, P. stipulacea and M. caesalpiniifolia seeds are retained for a longer period in the intestine of the animals, with the highest number obtained 72 and 96 h after, respectively. The passage of seeds through the digestive system of D. virgatus for 24 h and P. stipulacea for 72 h, promoted the overcoming of dormancy, reaching Ger values of 66.7 and 35.7%, respectively. The Ger of M. tenuiflora seeds as well as the Ger and survival of M. caesalpiniifolia seeds decreased after passing through the digestive system. The recovery of seeds from the four species indicates that goats are efficient seed dispersers in Caatinga areas. [ABSTRACT FROM AUTHOR]

Waterbird‐mediated endozoochory is an essential mechanism for the dispersal of sessile organisms in freshwater ecosystems. However, in the neotropics there are no previous studies of how different waterbird species vary in the dispersal functions they perform, and how seasonality influences endozoochory. In this study, we identified plant diaspores dispersed in faeces of five South American waterfowl (Brazilian teal Amazonetta brasiliensis, yellow‐billed teal Anas flavirostris, ringed teal Callonetta leucophrys, coscoroba swan Coscoroba coscoroba, and white‐faced whistling‐duck Dendrocygna viduata).We collected 165 faecal samples from five wetlands in southern Brazil surrounded by pasture and rice fields, then separated and measured intact seeds and other diaspores. Using generalised linear models, we tested how diaspore abundance and taxonomic richness differed among bird species and between cold (April–September) and warm (October–March) periods. We also analysed bird‐specific and seasonal variations in diaspore composition through principal coordinates analysis and permutational multivariate analysis of variance. We used indicator species analysis to determine which diaspore species discriminated between bird species and seasons. Finally, we measured diaspore length in order to analyse differences among waterfowl species in the size of diaspores dispersed.We found 2,066 intact diaspores from 40 different plant taxa, including seeds of 37 angiosperms and diaspores of Lycophyta (Isoetes cf. maxima), Pteridophyta (Azolla filiculoides), and Charophyceae. There was at least one diaspore in 65% of all faecal samples. Diaspores of native amphibious and emergent plants were dominant. We found 1,835 diaspores (from 33 taxa) in the cold period but only 231 (23 taxa) in the warm period. Seeds of the grass Zizaniopsis bonariensis and of the sedge Rynchospora sp. were the most abundant taxa. A strong interaction between bird species and season was the most important predictor of variation in both taxonomic richness and abundance of diaspores. The taxonomic composition of diaspores differed among waterfowl species and season. Indicator species analysis identified 12 plant taxa associated with particular bird species and seasons. Coscoroba swan, the largest bodied species in our study dispersed a higher proportion (8.2%) of large (length >2 mm) seeds.Despite considerable overlap, there are important differences in the plants dispersed by each species, and the smallest (ringed teal) and largest (coscoroba swan) birds are particularly different. All five waterfowl species are distributed over wide areas of South America and here we demonstrated that they are likely to be important plant vectors connecting wetland species at different geographical scales. Many of these plants have previously been assumed to lack mechanisms for long‐distance dispersal. [ABSTRACT FROM AUTHOR]

This study evaluated the potential of lowland tapirs as seed dispersers in the northern Brazilian Amazon. The study analyzed the viability of seeds after passage through the gut. Fecal samples were collected from 6 different vegetation physiognomies in Viruá National Park during the dry season. The samples were then kept in a greenhouse for 16 months to allow the seeds to germinate. The seedling species were identified and classified according to the type of fruit, plant habit, seed size and type of ingestion. Of the 111 fecal samples, 94 (84.7%) had viable seeds of 75 species. Melastomataceae was the most frequent family with viable seeds in the fecal samples (69.1% of samples, N= 18 species). The data suggest that the importance of the lowland tapirs as dispersers is not restricted to the species consumed actively by frugivory but also extends to species accidentally consumed during browsing. The occurrence of both large and small viable seeds in the fecal samples as well as a number of large drupes, which probably cannot be transported via endozoochory by any other animal species, provide evidence of the ecological importance of lowland tapirs to the dynamics of the forest-campinarana vegetation mosaic in the region. [ABSTRACT FROM AUTHOR]

We studied the assemblage of seed species and other food items defecated by juvenile and adult male and female individuals of Artibeus jamaicensis (Phyllostomidae) in three habitats in the Pantanal wetlands. The most frequent item in A. jamaicensis fecal samples were seeds (65%), followed by fruit pulp (30%), insects (20%), leaves (8%), and pollen (7%). Seeds of Ficus pertusa, F. gomelleira, Ficus sp., and Cecropia pachystachya were recorded in fecal samples from all three habitats while seeds of Banara arguta were exclusive to riparian forests. The relative occurrence of seed species in the fecal samples did not differ among sex or different-aged individuals. Ficus pertusa was the most common seed species and presented fast germination after passing through bats. Seeds of C. pachystachya which passed through A. jamaicensis had a lower germination rate than those uneaten. Overall results support that A. jamaicensis feeds on a relatively poor assemblage of fruits in the Pantanal. [ABSTRACT FROM AUTHOR]

Aim To assess the geographical variation in the relative importance of vertebrates, and more specifically of birds and mammals, as seed dispersal agents in forest communities, and to evaluate the influence of geographical and climatic factors on the observed trends. Location One hundred and thirty-five forest communities in the Brazilian Atlantic forest. Methods We collected data on dispersal modes for 2292 woody species. By combining species × site with species × trait matrices, we obtained the percentages of endozoochory, ornithochory, mastozoochory and the mean fruit diameter for the local forest communities. We used Spearman's correlation to assess bivariate relationships between variables. Subsequently, we performed paired t-tests to verify if variations in frequency of dispersal modes and mean fruit diameter were influenced by altitude or temperature. Then, we applied multiple linear regressions to evaluate the effect of geographical and climatic variables on variation in the relative frequency of dispersal modes and mean fruit diameter across communities. Results We found no consistent latitudinal or longitudinal trend in the percentage of vertebrate-dispersed species, neither bird- nor mammal-dispersed species along the Atlantic forest. Endozoochory was affected chiefly by annual mean rainfall, increasing towards moister sites. Forest communities located at higher altitudes had a higher percentage of bird-dispersed species. Even when sites with identical values of annual mean temperature were compared, altitude had a positive effect on ornithochory. Conversely, we found a higher percentage of mammal-dispersed species in warmer forests, even when locations at the same altitudinal belts were contrasted. Fruit diameter was clearly related to altitude, decreasing towards higher elevations. Main conclusions This is the first analysis of a large data set on dispersal syndromes in tropical forest communities. Our findings support the hypotheses that: (1) geographical variation in the relative number of fleshy fruit species is mainly driven by moisture conditions and is relatively independent of geographical location, and (2) broad-scale trends in fruit size correspond to geographical variation in the relative importance of mammals and birds as seed dispersal agents at the community level. [ABSTRACT FROM AUTHOR]

Primates are great fruit consumers and disperse intact seeds from most of the plants they consume, but effective seed dispersal depends, amongst other factors, on handling behavior. Likewise, the treatment in gut and mouth may alter seed fate. Overall, frugivore and folivore-frugivore primates are recognized to provide beneficial gut treatment for Neotropical plant species, but this effect might be overlooked at species-specific levels. In this study, we assessed the role of the southern muriqui (Brachyteles arachnoides), an endangered and endemic primate living in restricted fragments of the Brazilian Atlantic Forest, on potential quality of seed dispersal of native plants. Our main goals were to understand the effect of seed ingestion by this large-bodied atelid on germination of defecated seeds and in seed recovery by offering wild fruits of native species to captive individuals. We found that seven out of nine plant species were defecated intact and were able to germinate. Of those seven, one species showed enhanced and another showed decreased germination potential after defecation, while three species germinated faster after being defecated. The remaining species showed no differences from control seeds. The two non-germinating species were heavily predated, and average seed recovery was lower than expected, suggesting high levels of seed predation. The largest species offered (Inga vulpina) showed the highest dispersal potential. Our data support an overall neutral or potentially positive role of southern muriquis in seed dispersal quality for seven out of nine Atlantic Forest plant species, highlighting these primates' potential to produce an effective seed rain.

For the first time to our knowledge, we demonstrate that whole angiosperm individuals can survive gut passage through birds, and that this occurs in the field. Floating plants of the genus Wolffia are the smallest of all flowering plants. Fresh droppings of white-faced whistling duck Dendrocygna viduata ( n = 49) and coscoroba swan Coscoroba coscoroba ( n = 22) were collected from Brazilian wetlands. Intact Wolffia columbiana were recovered from 16% of D. viduata and 32% of Coscoroba samples (total = 164 plantlets). The viability of plants was tested, and asexual reproduction was confirmed. Wolffia columbiana is an expanding alien in Europe. Avian endozoochory of asexual angiosperm propagules may be an important, overlooked dispersal means for aquatic plants, and may contribute to the invasive character of alien species.