RESUMO

Nurse plants provide benefits during the early life cycle of the protected plant by reducing the intensity of stressful abiotic conditions. However, nurse plants may influence frugivore visitation and consumption, affecting the initial benefits of this interaction and generating different frugivory patterns during the reproductive phase of the protégé. Despite the importance of nurse plants and frugivory in the structure and composition of ecosystems, they have rarely been evaluated together, and frugivory patterns caused by nurse plants at different spatial and temporal scales are mostly unknown. Pilosocereus leucocephalus produces seeds that are endozoochorically dispersed by birds and mammals, can establish in open spaces devoid of arboreal vegetation (OS), and is associated with the nurse tree Lysiloma acapulcensis. However, the influence of L. acapulcensis on the frugivory patterns of P. leucocephalus is unknown. Therefore, during the fruiting season of P. leucocephalus of 2018, we recorded the visitation rates, effective removal, and removal timescales in 26 individuals located in OS and 15 under L. acapulcensis. Our results indicate that L. acapulcensis increased visits by Euphonia hirundinacea and bats but decreased those of Psilorhinus morio and Campylorhynchus rufinucha. Although L. acapulcensis did not generate differences in fruit removal effectiveness, bats showed the highest effectiveness in OS, followed by birds. L. acapulcensis also had an effect on the fruit removal periods of different frugivorous species at different temporal scales. This shows that the nurse tree generated a complex pattern of frugivory in P. leucocephalus, mainly increasing the initial benefits of the nurse-protégé interaction.

Assuntos

RESUMO

Euterpe edulis Martius (Arecaceae) is considered one of the most important palm trees for the dispersing and pollinating fauna in the Atlantic Forest. However, the predatory exploitation of the palm heart has been causing its decline and extinction throughout the Atlantic Forest. The aim of this study was to identify the interactions between mammals and birds with Juçara palm, as well as contribute to the understanding of the ecological processes of seed dispersal and germination. The study was carried out in the municipality of Maquiné, state of Rio Grande do Sul, in an area of Dense Ombrophylous Forest belonging to Fundação Estadual de Pesquisa Agropecuária (FEPAGRO). Mammals and birds were recorded with six camera traps, focal (tree-focal) observation and transections. Germination experiments were also performed and differences were tested using Biostat 5.3 software. Twelve months of study resulted in over 1300 videos with a sampling effort of 334 camera days. In 1180 videos, the fauna interacted directly with the fruits of E. edulis, totaling 1245 interactions. In 38% of these, fruits were consumed, which were carried in 37% of these records and in 25%, swallowed. In total, 17 species were recorded, 12 birds and five mammals. Of these, small rodents were the ones that consumed or carried the fruits the most (N = 616 or 65%). Of the birds, four Turdus species consumed, swallowed or carried 322 fruits (33%). The percentage and / or the germination speed were significantly higher in regurgitated or pulped seeds by the fauna than in seeds extracted directly from the plant. Large frugivores were eventually recorded, suggesting a defaunation in the study area. The number of interactions verified, however, confirms the ecological importance of E. edulis for the maintenance of the frugivorous guild with occurrence in the locality.(AU)

Euterpe edulis Martius (Arecaceae) é considerada uma das palmeiras mais importantes para a fauna dispersora e polinizadora na Mata Atlântica. Contudo, a exploração predatória do palmito vem causando seu declínio e extinção ao longo da Mata Atlântica. O objetivo deste estudo foi identificar as interações entre mamíferos e aves com E. edulis Mart., bem como contribuir para a compreensão dos processos ecológicos de dispersão e germinação de sementes. O estudo foi realizado no município de Maquiné, RS, em área de Floresta Ombrófila Densa pertencente à Fundação Estadual de Pesquisa Agropecuária (FEPAGRO). Mamíferos e aves foram registrados por meio da utilização de seis armadilhas de filmagem, observação focal (árvore-focal) e transecções. Experimentos de germinação foram também realizados e as diferenças encontradas foram testadas por meio do programa Biostat 5.3. Doze meses de estudo resultaram em mais de 1300 vídeos com um esforço amostral de 334 armadilhas-dia. Em 1180 vídeos, a fauna interagiu diretamente com os frutos de E. edulis, totalizando 1245 interações. Em 38% destas houve consumo dos frutos, os quais foram carregados em 37% desses registros e em 25%, engolidos. No total, foram registradas 17 espécies, 12 de aves e cinco de mamíferos. Destes, os pequenos roedores foram os que mais consumiram ou carregaram os frutos (N=616 ou 65%). Das aves, quatro espécies de Turdus consumiram, engoliram ou carregaram 322 frutos (33%). O percentual e/ou a velocidade de germinação foram significativamente maiores em sementes regurgitadas ou despolpadas pela fauna do que em sementes extraídas diretamente da planta. Grandes frugívoros foram eventualmente registrados, sugerindo um quadro de defaunação na área de estudo. O número de interações constatadas, contudo, confirma a importância ecológica de E. edulis para a manutenção da guilda de frugívoros com ocorrência na localidade.(AU)

Assuntos

RESUMO

Euterpe edulis Martius (Arecaceae) is considered one of the most important palm trees for the dispersing and pollinating fauna in the Atlantic Forest. However, the predatory exploitation of the palm heart has been causing its decline and extinction throughout the Atlantic Forest. The aim of this study was to identify the interactions between mammals and birds with Juçara palm, as well as contribute to the understanding of the ecological processes of seed dispersal and germination. The study was carried out in the municipality of Maquiné, state of Rio Grande do Sul, in an area of Dense Ombrophylous Forest belonging to Fundação Estadual de Pesquisa Agropecuária (FEPAGRO). Mammals and birds were recorded with six camera traps, focal (tree-focal) observation and transections. Germination experiments were also performed and differences were tested using Biostat 5.3 software. Twelve months of study resulted in over 1300 videos with a sampling effort of 334 camera days. In 1180 videos, the fauna interacted directly with the fruits of E. edulis, totaling 1245 interactions. In 38% of these, fruits were consumed, which were carried in 37% of these records and in 25%, swallowed. In total, 17 species were recorded, 12 birds and five mammals. Of these, small rodents were the ones that consumed or carried the fruits the most (N = 616 or 65%). Of the birds, four Turdus species consumed, swallowed or carried 322 fruits (33%). The percentage and / or the germination speed were significantly higher in regurgitated or pulped seeds by the fauna than in seeds extracted directly from the plant. Large frugivores were eventually recorded, suggesting a defaunation in the study area. The number of interactions verified, however, confirms the ecological importance of E. edulis for the maintenance of the frugivorous guild with occurrence in the locality.

Euterpe edulis Martius (Arecaceae) é considerada uma das palmeiras mais importantes para a fauna dispersora e polinizadora na Mata Atlântica. Contudo, a exploração predatória do palmito vem causando seu declínio e extinção ao longo da Mata Atlântica. O objetivo deste estudo foi identificar as interações entre mamíferos e aves com E. edulis Mart., bem como contribuir para a compreensão dos processos ecológicos de dispersão e germinação de sementes. O estudo foi realizado no município de Maquiné, RS, em área de Floresta Ombrófila Densa pertencente à Fundação Estadual de Pesquisa Agropecuária (FEPAGRO). Mamíferos e aves foram registrados por meio da utilização de seis armadilhas de filmagem, observação focal (árvore-focal) e transecções. Experimentos de germinação foram também realizados e as diferenças encontradas foram testadas por meio do programa Biostat 5.3. Doze meses de estudo resultaram em mais de 1300 vídeos com um esforço amostral de 334 armadilhas-dia. Em 1180 vídeos, a fauna interagiu diretamente com os frutos de E. edulis, totalizando 1245 interações. Em 38% destas houve consumo dos frutos, os quais foram carregados em 37% desses registros e em 25%, engolidos. No total, foram registradas 17 espécies, 12 de aves e cinco de mamíferos. Destes, os pequenos roedores foram os que mais consumiram ou carregaram os frutos (N=616 ou 65%). Das aves, quatro espécies de Turdus consumiram, engoliram ou carregaram 322 frutos (33%). O percentual e/ou a velocidade de germinação foram significativamente maiores em sementes regurgitadas ou despolpadas pela fauna do que em sementes extraídas diretamente da planta. Grandes frugívoros foram eventualmente registrados, sugerindo um quadro de defaunação na área de estudo. O número de interações constatadas, contudo, confirma a importância ecológica de E. edulis para a manutenção da guilda de frugívoros com ocorrência na localidade.

Assuntos

RESUMO

The spatial variation in the outcome of the interaction between secondary dispersers and seeds is superimposed upon the variation produced by primary dispersers. Investigating the factors that drive the outcome of the interactions with secondary seed dispersers thus represents an essential refinement to our understanding of the complete seed dispersal process. We studied the interactions between two ponerine ants (Pachycondyla striata Smith, 1858 and Odontomachus chelifer (Latreille, 1802)) with fruits experimentally set on the ground, and estimated the effects of ants on seedling establishment in three areas distributed along a 2-km stretch of a Brazilian Atlantic rainforest that differ in soil properties and vegetation physiognomies. We tested the hypothesis that interactions are more frequent, resulting in greater seedling establishment at the site with harsher abiotic and biotic conditions. Both ant species removed fruits frequently and have a positive effect on seedling establishment in all study areas, but fruit removal did not differ among areas, while seedling establishment was more pronounced at the site with stressful abiotic conditions. The two ant species differed in important aspects of their seed dispersal services, including the propensity to interact with seeds. As a result, both the species of ant and abiotic conditions interact at the scale of 2 km to determine the fate of seeds interacting with ants, thus creating a mosaic of outcomes with variable benefits to plants.

Assuntos

RESUMO

This study was carried out to investigate the effects of different AVG (aminoethoxyvinylglycine) treatments on pre-harvest fruit drop rates and ripening levels of Jonagold apples. A total of 225 mg L-1 AVG dose was applied at once in a single application at different times or divided into doses and applied different times. Compared to control treatment, entire AVG treatments increased fruit removal force and significantly decreased the pre-harvest drop rates. AVG treatments applied at once (225 mg L-1) 8 or 4 weeks before the anticipated harvest time were found to be more effective than the divided treatments. AVG treatments inhibited ethylene biosynthesis and such an inhibition was more distinctive in single 225 mg L-1 treatments. AVG treatments decreased flesh softening, starch degradation rates and consequently retarded fruit ripening. The 225 mg L-1 AVG treatment applied 4 weeks before the harvest significantly increased L* value and hue angle both in the year 2010 and 2011. NAA (naphtaleneacetic acid) at 10 mg L-1 sprayed 4 and 2 weeks before anticipated harvest was found to be insignificant in control of pre-harvest fruit drops. NAA treatment decreased flesh firmness, and did not have any significant effects on ethylene biosynthesis.(AU)

O presente estudo foi realizado para investigar os efeitos de diferentes tratamentos AVG (aminoetoxivinilglicina) sobre as taxas de queda de frutos antes da colheita e níveis de amadurecimento de maçãs Jonagold. Foi aplicada uma dose AVG total de 225 mg L-1 numa só vez numa única aplicação em momentos diferentes ou dividida em doses aplicadas e tempos diferentes. Em comparação ao tratamento controle, as aplicações de AVG aumentaram a força de remoção dos frutos e reduziram significativamente as taxas de queda na pré-colheita. A aplicação de AVG de uma só vez (225 mg L-1) ou 4 a 8 semanas antes da época da colheita mostrou-se mais eficaz do que as aplicações efetuadas em doses. O tratamento com AVG inibe a biossíntese de etileno, sendo que esta inibição se verificou mais significativa em tratamentos individuais de 225 mg L-1. O tratamento com AVG diminuiu o amolecimento da polpa, as taxas de degradação do amido e consequentemente retardou o amadurecimento dos frutos. O tratamento com doses de 225 mg L-1 de AVG aplicadas quatro semanas antes da colheita aumentou significativamente o valor L * e o ângulo de cor, tanto no ano de 2010 como de 2011. A pulverização de NAA (ácido naftaleno acético) a 10 mg L-1 2 a 4 semanas antes da colheita foi considerada insignificante no controle da queda de frutos na pré-colheita. O tratamento com NAA diminuiu a firmeza da polpa, e não tem quais...(AU)

Assuntos

RESUMO

This study was carried out to investigate the effects of different AVG (aminoethoxyvinylglycine) treatments on pre-harvest fruit drop rates and ripening levels of Jonagold apples. A total of 225 mg L-1 AVG dose was applied at once in a single application at different times or divided into doses and applied different times. Compared to control treatment, entire AVG treatments increased fruit removal force and significantly decreased the pre-harvest drop rates. AVG treatments applied at once (225 mg L-1) 8 or 4 weeks before the anticipated harvest time were found to be more effective than the divided treatments. AVG treatments inhibited ethylene biosynthesis and such an inhibition was more distinctive in single 225 mg L-1 treatments. AVG treatments decreased flesh softening, starch degradation rates and consequently retarded fruit ripening. The 225 mg L-1 AVG treatment applied 4 weeks before the harvest significantly increased L* value and hue angle both in the year 2010 and 2011. NAA (naphtaleneacetic acid) at 10 mg L-1 sprayed 4 and 2 weeks before anticipated harvest was found to be insignificant in control of pre-harvest fruit drops. NAA treatment decreased flesh firmness, and did not have any significant effects on ethylene biosynthesis.

O presente estudo foi realizado para investigar os efeitos de diferentes tratamentos AVG (aminoetoxivinilglicina) sobre as taxas de queda de frutos antes da colheita e níveis de amadurecimento de maçãs Jonagold. Foi aplicada uma dose AVG total de 225 mg L-1 numa só vez numa única aplicação em momentos diferentes ou dividida em doses aplicadas e tempos diferentes. Em comparação ao tratamento controle, as aplicações de AVG aumentaram a força de remoção dos frutos e reduziram significativamente as taxas de queda na pré-colheita. A aplicação de AVG de uma só vez (225 mg L-1) ou 4 a 8 semanas antes da época da colheita mostrou-se mais eficaz do que as aplicações efetuadas em doses. O tratamento com AVG inibe a biossíntese de etileno, sendo que esta inibição se verificou mais significativa em tratamentos individuais de 225 mg L-1. O tratamento com AVG diminuiu o amolecimento da polpa, as taxas de degradação do amido e consequentemente retardou o amadurecimento dos frutos. O tratamento com doses de 225 mg L-1 de AVG aplicadas quatro semanas antes da colheita aumentou significativamente o valor L * e o ângulo de cor, tanto no ano de 2010 como de 2011. A pulverização de NAA (ácido naftaleno acético) a 10 mg L-1 2 a 4 semanas antes da colheita foi considerada insignificante no controle da queda de frutos na pré-colheita. O tratamento com NAA diminuiu a firmeza da polpa, e não tem quais...

Assuntos

RESUMO

We studied the relationship between the removal rate and the spatiotemporal availability of ripe fruits of the tropical deciduous shrub Erythroxylum havanense in western Mexico. We also evaluated the effects of dispersal on seed survival during the first stages of establishment. Fast and early dispersal should be favored in E. havanense, since propagules have more time to grow and accumulate resources before the beginning of the severe dry season. In general, high rates of fruit removal imply faster and earlier dispersal. Thus, plants producing large crops should benefit from high removal rates, which will increase the probability of successful establishment by their progeny. To characterize both individual and population fruiting patterns, we made daily counts of fruits on 51 plants arranged in six clumps of different sizes. The daily number of fruits removed per plant was higher for plants with larger initial crop sizes and larger numbers of ripe fruits on a given day, but decreased as clump size increased. Additionally, we monitored postdispersal survival and germination in an experiment manipulating seed density, distance from adult plants, and seed predation. Early establishment was independent of density or distance, and vertebrate seed predation was the main agent of seed mortality. Our results indicate that the critical variable with respect to fruit removal is the number of fruits a plant produces, large plants having higher dispersal rates. Large plants are also more likely to have more seeds escaping postdispersal seed predation.