Structure and characteristics of the plant-frugivore bird network from the Guilin Botanical Garden.

The interaction between plants and frugivores is crucial to ecosystem function and community diversity. However, little is known about the interaction between plants and frugivorous bird species in urban green spaces. We observed interactions between plants and frugivorous birds in the Guilin Botanical Garden for one year and determined the structure and characteristics of the interaction network. We also analyzed the impact of species traits on their network roles. Interactions between 14 frugivorous birds and 13 fruit plant species were recorded in the study area. Autumn interactions comprised 38.79% of the overall network, and winter interactions comprised 33.15%. The modularity (Q, z-score) of the network was higher in autumn; the weighted nestedness (wNODF, z-score) and interaction evenness (E2 , z-score) of the network were higher in winter; the connectance (C, z-score) and interaction diversity (z-score) of the network were higher in spring; and the specialization (H2', z-score) of the network was higher in summer. The observed network showed lower C, lower interaction H2 , lower E2 , lower wNODF, higher H2' and higher Q when compared to the random networks. The bird species most important to network stability were Hemixos castanonotus, Parus venustulus, and Pycnonotus sinensis. The most important plant species were Alocasia macrorrhiza, Cinnamomum camphora, and Machilus nanmu. Of all the bird and plant traits included in this study, only plant color had a significant impact on species strength, with black fruit having a higher species strength. Our results suggest that interaction networks in urban green spaces can be temporally complex and variable and that a network approach can be an important monitoring tool for detecting the status of crucial ecosystem functions.

Onto the sense of smell in macaws, amazons and toucans: can they use volatile cues of fruits to make foraging decisions?

Over the past decades, empirical evidence has been accumulated indicating that olfactory information plays a fundamental role in bird life history. Nonetheless, many aspects of avian olfaction remain poorly understood. Our purpose was to broaden the knowledge about the importance of the sense of smell in some neglected bird groups: psittaciformes and ramphastids, and to compare how the response varied between the species. Because of the lack of information about the use of chemical cues for locating food in fruit-eating species, we also aimed to delve into this question. We conducted a 3-choice (water/vinegar/papaya and banana juice) scent test in 5 Costa Rican native species: scarlet macaw (Ara macao), red-lored amazon (Amazona autumnalis), yellow-naped amazon (Amazona auropalliata), keel-billed toucan (Ramphastos sulfuratus), and yellow-throated toucan (Ramphastos ambiguus). Results revealed that macaws and toucans allocated significantly more time to interacting with the fruit scent container, indicating that these species can perceive the volatile chemicals emitted by ripe fruits and that they can use this information to make foraging decisions. However, amazons did not dedicate more time to interact with the fruit treatment. Our research provides the first evidence of the ability to exploit chemical volatile cues in macaws and toucans.

Fruit Size and Structure of Zoochorous Trees: Identifying Drivers for the Foraging Preferences of Fruit-Eating Birds in a Mexican Successional Dry Forest.

Tropical dry forests (TDFs) are affected by land-use changes. These modifications impact their composition and arboreal structure, as well as the availability of food for several bird groups. In this study, we evaluated the foraging preferences in zoochorous trees of fruit-eating birds during the dry season of the year in three successional stages (early, intermediate, and mature) of TDFs in southern Mexico. The fruits of these trees are important in the diet of several birds during the dry season, a period during which food resources are significantly reduced in TDFs. We estimated foliar cover (FC) and foliage height diversity (FHD) of zoochorous trees in 123 circular plots. These variables were recognized as proxies of food availability and tree productivity. Foraging preferences were evaluated at the community level, by frugivore type, and by bird species. We evaluated the effect of the structural variables and the fruit size of zoochorous plants on fruit removal by birds and related the bird body mass and fruit size removed in the successional gradient. A total of 14 zoochorous tree species and 23 fruit-eating bird species were recorded along the successional gradient. Intermediate and mature stages showed greater fruit removal. The birds removed mainly B. longipes fruits across the three successional stages. The FHD and fruit size were important drivers in the selection of zoochorous trees and fruit removal by fruit-eating birds. Fruit size and bird body mass were positively related along the successional gradient. The results suggest that fruit removal by fruit-eating birds in the successional gradient can promote the demographic dynamics of several zoochorous tree species, especially of Bursera spp. along the TDFs.

Seed-dispersing bird assemblages in riparian environments of a partially urbanized river basin, Southeastern Brazil / Assembleias de aves dispersoras de sementes em ambientes ripários de uma bacia hidrográfica parcialmente urbanizada, no sudoeste brasileiro

Abstract Birds play a key role in ecosystem dynamics, including urban and rural areas, bringing environmental quality improvements and ecological stability. Species contribute directly to natural regeneration of vegetation and succession processes, by offering ecosystem services as seed dispersal, an important role in human-modified areas. We studied the assemblages of fruit-eating birds in riparian environments of Monjolinho basin, central São Paulo state, southeastern Brazil. Birds were recorded in 41 points distributed in riparian ecosystems alongside waterbodies, in landscapes with five types of surrounding matrices: urban, periurban, farmland, and native vegetation. We described how assemblages are structured aiming to evaluate the possible influence of seasonality and landscape type. We recorded 39 bird species that can play a role as seed-dispersers, 32 in wet season and 32 in dry season. There were no significant differences in the diversity and dominance of species between seasons considering the entire area, indicating stability of basic assemblage structure. However, total number of individuals of all species recorded in different landscapes were influenced by seasonality. Also, the composition and abundance of species significantly changed between seasons, leading to a high dissimilarity with almost 50% of the species contributing with almost 90% of the observed variation. A higher taxonomic diversity and distinctness pointed to a wider array of possible seed dispersal services in natural areas, while the lowest values of indexes were found in human-modified areas. The higher number of non-related bird species during dry season contrasted with the higher number of individuals during wet season, indicating that there is more possible ecosystem services offered by frugivorous birds in driest period of the year, while in the rainy period the carrying capacity of the riparian environments was increased.

Resumo As aves desempenham um papel chave na dinâmica dos ecossistemas, incluindo áreas urbanas e rurais, e trazem melhorias na qualidade ambiental e estabilidade ecológica. As espécies contribuem diretamente com a regeneração natural da vegetação e processos de sucessão por oferecerem serviços ecossistêmicos como a dispersão de sementes, um papel fundamental em áreas alteradas. Nós estudamos a assembleia de espécies de aves que se alimentam de frutos em ambientes ripários da bacia do rio Monjolinho, região central do estado de São Paulo, sudeste do Brasil. As aves foram registradas em 41 pontos distribuídos em ecossistemas ripários ao longo dos corpos d'água, em paisagens com quatro tipos de matrizes em seu entorno: urbana, periurbana, rural e vegetação nativa. Nós descrevemos como as assembleias estão estruturadas, objetivando avaliar a possível influência da sazonalidade e do tipo de paisagem do entorno. Foram registradas 39 espécies de aves que podem desempenhar o papel de dispersoras de sementes, sendo 32 espécies no período chuvoso e 32 no período seco. Não foi detectada diferença significativa na diversidade e dominância de espécies entre estações em toda área de estudo, indicando estabilidade da estrutura básica das assembleias. Entretanto, o número total de indivíduos de todas as espécies registrados nas diferentes paisagens foi influenciado pela sazonalidade. Além disso, a composição e abundância de espécies mudou significativamente entre as estações, levando a uma alta dissimilaridade com quase 50% das espécies contribuindo com quase 90% da variação observada. A diversidade e distinção taxonômicas mais altas apontam para maior variedade de serviços ecossistêmicos possíveis relacionados à dispersão de sementes em áreas naturais, enquanto os menores valores desses índices foram encontrados em áreas antropizadas. Um maior número de espécies distintas com menor proximidade taxonômica durante a estação seca, em contraste com um alto número de indivíduos observados na estação chuvosa, indica que existe uma maior gama de possíveis serviços ecossistêmicos oferecidos pelas aves frugívoras no período mais seco do ano, enquanto no período de maior pluviosidade os ecossistemas apresentaram maior capacidade suporte.

Similar seed dispersal systems by local frugivorous birds in native and alien plant species in a coastal seawall forest.

Frugivorous birds play an important role in seed dispersal. Alien plant species' seeds are dispersed by local birds in order to establish populations in new habitats. Alien plant species that produce fruits similar to that of native species have the potential to attract local birds, creating new mutualistic systems that are similar to the local ones. In autumn 2018 and 2019, we studied the seed dispersal systems of an alien plant species, Phytolacca americana, and a native species, Cayratia japonica, in a coastal seawall forest. Both plant species' fruit, frugivorous bird foraging behaviors, seed germination rates, and seedling microhabitats were examined to determine whether the alien species had a similar seed dispersal system to that of the native species. Our results showed that P. americana and C. japonica had similar fruit type, color, and ripening period. There was a positive correlation between the percentage rate of fruit ripening and the percentage rate of fruit missing for both plant species, indicating that local frugivorous birds have the potential to sufficiently disperse the alien seeds to enable its spread in the coastal seawall forest (simple linear regression, P. americana: ß = 0.863 ± 0.017, R2 adj = 0.978, P < 0.01; C. japonica: ß = 0.787 ± 0.034, R2 adj = 0.898, P < 0.01). Eleven bird species consumed the fruits of the alien species or native species during the study period. Similar results were shown across alien and native species in bird foraging behavior (feeding frequency, feeding duration and first stop distance) indicating that a similar seed dispersal relationship had been established between local frugivorous and both plant species. The alien plant had a higher number of fruits carried by birds, suggesting that P. americana had a slightly higher fruit consumption than that of C. japonica (t-test, P < 0.01). Alien plant seedlings grow more abundant in forest gap microhabitat (t-test, P < 0.01). Our results confirmed that bird digestion promotes seed germination success in both plant species. Our study suggests that in a narrow coastal seawall forest, alien plant species can successfully establish their populations by relying on similar seed dispersal systems as the local species.

Eggs survive through avian guts-A possible mechanism for transoceanic dispersal of flightless weevils.

How flightless animals disperse to remote oceanic islands is a key unresolved question in biogeography. The flightless Pachyrhynchus weevils represent repetitive colonization history in West Pacific islands, which attracted our interests about how some weevils have successfully dispersed in the reverse direction against the sea current. Here, we propose endozoochory as a possible mechanism that the eggs of the weevils might be carried by embedded in the fruits as the food of frugivorous birds. In this study, Pachyrhynchus eggs were embedded in small pieces of persimmon fruits (Diospyros kaki) and fed to captive frugivorous birds. After digestion, 83%-100% eggs were retrieved from the feces of a bulbul (Hypsipetes leucocephalus) and two thrushes (Turdus chrysolaus). The retrieved eggs had hatching rates higher than 84%, which were not different from the control. In contrast, no egg was retrieved from the feces of the frugivorous pigeon (Treron sieboldii), which took a longer retention time in the guts. Our study identified that the eggs of Pachyrhynchus weevils are possible to be transported by internal digesting in some bird species.

The impact of tree crops and temperature on the timing of frugivorous bird migration.

Migration has evolved to tackle temporal changes in availability of resources. Climate change has been shown to affect the migration dates of species, which raises the question of whether the variation in the timing of migration is climate or resource dependent? The relative importance of temperature and availability of food as drivers of migration behaviour during both spring and autumn seasons has been poorly studied. Here, we investigated these patterns in frugivorous and granivorous birds (hereafter frugivorous) that are assumed to postpone their autumn migration when there is plenty of food available, which may also advance upcoming spring migration. On the other hand, especially spring migration dates have been negatively connected with increasing temperatures. We tested whether the autumn and spring migration dates of eleven common frugivorous birds depended on the crop size of trees or ambient temperatures using 29 years of data in Finland. The increased crop sizes of trees delayed autumn migration dates; whereas, autumn temperature did not show a significant connection. We also observed a temporal trend towards later departure. Increasing temperature and crop sizes advanced spring arrival dates. Our results support the hypothesis that the timing of autumn migration in the frugivorous birds depends on the availability of food and is weakly connected with the variation in temperature. Importantly, crop size can have carry-over effects and affect the timing of spring arrival possibly because birds have overwintered closer to the breeding grounds after an abundant crop year.

Intercontinental long-distance seed dispersal across the Mediterranean Basin explains population genetic structure of a bird-dispersed shrub.

Long-distance dispersal (LDD) is a pivotal process for plants determining their range of distribution and promoting gene flow among distant populations. Most fleshy-fruited species rely on frugivorous vertebrates to disperse their seeds across the landscape. While LDD events are difficult to record, a few ecological studies have shown that birds move a sizeable number of ingested seeds across geographic barriers, such as sea straits. The foraging movements of migrant frugivores across distant populations, including those separated by geographic barriers, creates a constant flow of propagules that in turn shapes the spatial distributions of the genetic variation in populations. Here, we have analysed the genetic diversity and structure of 74 populations of Pistacia lentiscus, a fleshy-fruited shrub widely distributed in the Mediterranean Basin, to elucidate whether the Mediterranean Sea acts as a geographic barrier or alternatively whether migratory frugivorous birds promote gene flow among populations located on both sides of the sea. Our results show reduced genetic distances among populations, including intercontinental populations, and they show a significant genetic structure across an eastern-western axis. These findings are consistent with known bird migratory routes that connect the European and African continents following a north-southwards direction during the fruiting season of many fleshy-fruited plants. Further, approximate Bayesian analysis failed to explain the observed patterns as a result of historical population migrations at the end of Last Glacial Maximum. Therefore, anthropic and/or climatic changes that would disrupt the migratory routes of frugivorous birds might have genetic consequences for the plant species they feed upon.

Endozoochory of frugivorous birds as potential dispersal of seed parasites from Pistacia chinesis: experimental evidence.

The plant-disperser-fruit pest triads involve 3 interacting animals or groups (plants, vertebrates and seed parasites), and the dispersal of both seeds and seed parasites, which can both benefit from endozoochory via defecation or regurgitation by frugivorous vertebrates. However, we have very limited knowledge about the ecological and evolutionary consequences of these plant-disperser-fruit pest triads. Across central Northern China, several seed wasps (mainly Eurytoma plotnikov attack Pistacia chinensis fruits, and seed wasp larvae can develop, diapause and finally emerge as adults inside a seed during the following 1-3 years. In this study, we experimentally investigated whether frugivorous birds discriminated P. chinesis fruits with or without seed parasites, and whether bird endozoochory (by defecation or regurgitation) affected larval survival of seed parasites. The infestation rate by seed parasites was 37% of the P. chinesis fruit crop but with up to 48% of aborted fruits. We found that all 5 bird species can discriminate and then reject all unhealthy fruits (including aborted and insect-infested). However, 4 of the 5 bird species, in particular bulbul species, consumed 15-41% of aborted and insect-infested fruits as complementary food only when these unhealthy fruits were provided. Moreover, all larva of seed parasites remained alive after bird defecation or regurgitation. In conclusion, our study demonstrates that endozoochory by frugivorous birds could lead to potential dispersal of seed parasites of P. chinensis but with a very low probability.

Effect of El Niño and La Niña on abundance of frugivorous and nectarivorous terrestrial birds in three tropical forests

El Niño and La Niña climatic oscillations have dramatic effects on population dynamics and community structure of different animals. For marine birds, El Niño phenomenon drastically increases their mortality and reduces their reproductive success. In terrestrial ecosystems, the lack of long-term longitudinal data limits our understanding of the impact of El Niño and La Niña on bird populations and communities. We analyzed changes in abundance of frugivorous (large, medium, and small) and nectarivorous birds on three tropical forest types (lowland, premontane and montane) during El Niño, La Niña and neutral years using data from 16 Christmas' Bird Counts in Costa Rica. Abundance of large and medium size frugivores increased during La Niña events, and the abundance of nectarivores during El Niño in the lowland forest, but neither of these events affected the abundance of small frugivores. In the montane forest, abundance of all four bird groups increased during El Niño, but decreased during La Niña events. Abundance of large, and small frugivores increased in the premontane forest during La Niña events, but other bird groups were not affected by La Niña. The abundance of small frugivores also increased during El Niño. We hypothesize that changes in abundance of frugivores and nectarivores during La Niña and El Niño events is probably correlated with fluctuations in food resources as it has been reported for other terrestrial tropical ecosystems.

Las oscilaciones climáticas causadas por el fenómeno de El Niño y La Niña tienen efectos drásticos sobre la dinámica de las poblaciones y la estructura de las comunidades. Para aves marinas, el fenómeno de El Niño incrementa drásticamente su mortalidad y reduce su éxito reproductivo. En ecosistemas terrestres, la falta de datos a largo plazo limita nuestro entendimiento sobre el impacto de El Niño y La Niña sobre la dinámica de las poblaciones y comunidades de aves. Nosotros analizamos los cambios en la abundancia de aves frugívoras (grandes, medianos y pequeños) y nectarívoras en tres tipos de bosque tropical (lluvioso de tierras bajas, premontano y montano) durante los años de El Niño, La Niña, y años neutrales usando datos de al menos 16 conteos de navidad (Christmas' Bird Counts) en Costa Rica. La abundancia de frugívoros grandes y medianos incrementó durante los años de La Niña, y la abundancia de nectarívoros durante el Niño en el bosque lluvioso de tierras bajas, pero ninguno de estos eventos afectó la abundancia de frugívoros pequeños en este bosque. En el bosque montano, la abundancia de los cuatro grupos de aves incrementó durante los años de El Niño, pero disminuyó durante los años de La Niña. La abundancia de frugívoros grandes y pequeños aumentó en el bosque pre-montano durante los años de La Niña; sin embargo, la abundancia de los frugívoros medianos y los nectarívoros no fue afectada por los eventos por La Niña o El Niño. La abundancia de frugívoros pequeños también aumentó durante El Niño en este bosque. Proponemos la hipótesis de que los cambios en la abundancia de las aves frugívoras y nectarívoras reflejan fluctuaciones en el recurso alimentario, como ha sido reportado en otros ecosistemas terrestres tropicales.

Aliens will provide: avian responses to a new temporal resource offered by ornithocorous exotic shrubs.

Frugivorous birds are able to track spatiotemporal changes in fruit availability. Food resource fluctuations, characteristic of seasonal environments, can be affected by the naturalization of exotic ornithocorous plants. In the mountain forest of central Argentina, invasive shrubs of the genus Pyracantha provide a new temporal resource that modifies fluctuations of natural resource availability because the invasives fructify in autumn-winter (largely uncoupled with the fruiting of native species). The contrasting patterns of resource fluctuation between non-invaded and invaded areas throughout the year provide a good study system to test predictions of the fruit-tracking hypothesis, and to understand the relationship between food resources offered by fleshy fruited invasives and abundances of avian trophic guilds. By means of point counts conducted during five time periods at invaded and non-invaded sites we found that the presence of Pyracantha, and time periods, significantly affected frugivorous bird abundance, which in autumn-winter was greater in invaded sites and in spring-summer similar between invaded and non-invaded sites. On the other hand, granivores and insectivores did not show a significant relationship with the presence of Pyracantha. Abundances of the most common seed disperser were significantly affected by the interaction between time period and presence of Pyracantha. These results indicate that the abundances of birds that legitimately disperse Pyracantha seeds are temporally and spatially associated with fruit abundance provided by this exotic plant. This underscores fruit availability as an important ecological factor affecting frugivorous bird abundance, and suggests that Pyracantha seed dispersers are capable of detecting changes in the availability of its fruit, likely contributing to the effectiveness of its dispersal.

Moving from frugivory to seed dispersal: Incorporating the functional outcomes of interactions in plant-frugivore networks.

There is growing interest in understanding the functional outcomes of species interactions in ecological networks. For many mutualistic networks, including pollination and seed dispersal networks, interactions are generally sampled by recording animal foraging visits to plants. However, these visits may not reflect actual pollination or seed dispersal events, despite these typically being the ecological processes of interest. Frugivorous animals can act as seed dispersers, by swallowing entire fruits and dispersing their seeds, or as pulp peckers or seed predators, by pecking fruits to consume pieces of pulp or seeds. These processes have opposing consequences for plant reproductive success. Therefore, equating visitation with seed dispersal could lead to biased inferences about the ecology, evolution and conservation of seed dispersal mutualisms. Here, we use natural history information on the functional outcomes of pairwise bird-plant interactions to examine changes in the structure of seven European plant-frugivore visitation networks after non-mutualistic interactions (pulp pecking and seed predation) have been removed. Following existing knowledge of the contrasting structures of mutualistic and antagonistic networks, we hypothesized a number of changes following interaction removal, such as increased nestedness and lower specialization. Non-mutualistic interactions with pulp peckers and seed predators occurred in all seven networks, accounting for 21%-48% of all interactions and 6%-24% of total interaction frequency. When non-mutualistic interactions were removed, there were significant increases in network-level metrics such as connectance and nestedness, while robustness decreased. These changes were generally small, homogenous and driven by decreases in network size. Conversely, changes in species-level metrics were more variable and sometimes large, with significant decreases in plant degree, interaction frequency, specialization and resilience to animal extinctions and significant increases in frugivore species strength. Visitation data can overestimate the actual frequency of seed dispersal services in plant-frugivore networks. We show here that incorporating natural history information on the functions of species interactions can bring us closer to understanding the processes and functions operating in ecological communities. Our categorical approach lays the foundation for future work quantifying functional interaction outcomes along a mutualism-antagonism continuum, as documented in other frugivore faunas.

Unravelling seed dispersal through fragmented landscapes: Frugivore species operate unevenly as mobile links.

Seed dispersal constitutes a pivotal process in an increasingly fragmented world, promoting population connectivity, colonization and range shifts in plants. Unveiling how multiple frugivore species disperse seeds through fragmented landscapes, operating as mobile links, has remained elusive owing to methodological constraints for monitoring seed dispersal events. We combine for the first time DNA barcoding and DNA microsatellites to identify, respectively, the frugivore species and the source trees of animal-dispersed seeds in forest and matrix of a fragmented landscape. We found a high functional complementarity among frugivores in terms of seed deposition at different habitats (forest vs. matrix), perches (isolated trees vs. electricity pylons) and matrix sectors (close vs. far from the forest edge), cross-habitat seed fluxes, dispersal distances and canopy-cover dependency. Seed rain at the landscape-scale, from forest to distant matrix sectors, was characterized by turnovers in the contribution of frugivores and source-tree habitats: open-habitat frugivores replaced forest-dependent frugivores, whereas matrix trees replaced forest trees. As a result of such turnovers, the magnitude of seed rain was evenly distributed between habitats and landscape sectors. We thus uncover key mechanisms behind "biodiversity-ecosystem function" relationships, in this case, the relationship between frugivore diversity and landscape-scale seed dispersal. Our results reveal the importance of open-habitat frugivores, isolated fruiting trees and anthropogenic perching sites (infrastructures) in generating seed dispersal events far from the remnant forest, highlighting their potential to drive regeneration dynamics through the matrix. This study helps to broaden the "mobile-link" concept in seed dispersal studies by providing a comprehensive and integrative view of the way in which multiple frugivore species disseminate seeds through real-world landscapes.

Dispersal of remnant endangered trees in a fragmented and disturbed forest by frugivorous birds.

Most endangered plant species in a fragmented forest behave as a unique source population, with a high dependence on frugivorous birds for recruitment and persistence. In this study, we combined field data of dispersal behavior of birds and GIS information of patch attributes to estimate how frugivorous birds could affect the effective dispersal pattern of Chinese yew (Taxus chinensis) in a fragmented and disturbed forest. Nine bird species were observed to visit T. chinensis trees, with Urocissa erythrorhyncha, Zoothera dauma and Picus canus being the most common dispersers. After foraging, six disperser species exhibited different perching patterns. Three specialist species, P. canus, Turdus hortulorum, and Z. dauma stayed in the source patch, while three generalist species, U. erythrorhyncha, Hypsipetes mcclellandii, and H. castanonotus, could perch in bamboo patches and varied in movement ability due to body size. As a consequence of perching, dispersers significantly contributed to the seed bank, but indirectly affected seedling recruitment. Moreover, the recruitment of T. chinensis was also affected by patch attributes in a fragmented forest (distances to source patch, patch type, size). Our results highlighted the ability of unique source population regeneration of T. chinensis in a fragmented forest, with high dependence on both frugivorous birds and patch attributes, which should be considered in future planning for forest management and conservation.

Seed-dispersing bird assemblages in riparian environments of a partially urbanized river basin, Southeastern Brazil

Abstract Birds play a key role in ecosystem dynamics, including urban and rural areas, bringing environmental quality improvements and ecological stability. Species contribute directly to natural regeneration of vegetation and succession processes, by offering ecosystem services as seed dispersal, an important role in human-modified areas. We studied the assemblages of fruit-eating birds in riparian environments of Monjolinho basin, central São Paulo state, southeastern Brazil. Birds were recorded in 41 points distributed in riparian ecosystems alongside waterbodies, in landscapes with five types of surrounding matrices: urban, periurban, farmland, and native vegetation. We described how assemblages are structured aiming to evaluate the possible influence of seasonality and landscape type. We recorded 39 bird species that can play a role as seed-dispersers, 32 in wet season and 32 in dry season. There were no significant differences in the diversity and dominance of species between seasons considering the entire area, indicating stability of basic assemblage structure. However, total number of individuals of all species recorded in different landscapes were influenced by seasonality. Also, the composition and abundance of species significantly changed between seasons, leading to a high dissimilarity with almost 50% of the species contributing with almost 90% of the observed variation. A higher taxonomic diversity and distinctness pointed to a wider array of possible seed dispersal services in natural areas, while the lowest values of indexes were found in human-modified areas. The higher number of non-related bird species during dry season contrasted with the higher number of individuals during wet season, indicating that there is more possible ecosystem services offered by frugivorous birds in driest period of the year, while in the rainy period the carrying capacity of the riparian environments was increased.

Resumo As aves desempenham um papel chave na dinâmica dos ecossistemas, incluindo áreas urbanas e rurais, e trazem melhorias na qualidade ambiental e estabilidade ecológica. As espécies contribuem diretamente com a regeneração natural da vegetação e processos de sucessão por oferecerem serviços ecossistêmicos como a dispersão de sementes, um papel fundamental em áreas alteradas. Nós estudamos a assembleia de espécies de aves que se alimentam de frutos em ambientes ripários da bacia do rio Monjolinho, região central do estado de São Paulo, sudeste do Brasil. As aves foram registradas em 41 pontos distribuídos em ecossistemas ripários ao longo dos corpos dágua, em paisagens com quatro tipos de matrizes em seu entorno: urbana, periurbana, rural e vegetação nativa. Nós descrevemos como as assembleias estão estruturadas, objetivando avaliar a possível influência da sazonalidade e do tipo de paisagem do entorno. Foram registradas 39 espécies de aves que podem desempenhar o papel de dispersoras de sementes, sendo 32 espécies no período chuvoso e 32 no período seco. Não foi detectada diferença significativa na diversidade e dominância de espécies entre estações em toda área de estudo, indicando estabilidade da estrutura básica das assembleias. Entretanto, o número total de indivíduos de todas as espécies registrados nas diferentes paisagens foi influenciado pela sazonalidade. Além disso, a composição e abundância de espécies mudou significativamente entre as estações, levando a uma alta dissimilaridade com quase 50% das espécies contribuindo com quase 90% da variação observada. A diversidade e distinção taxonômicas mais altas apontam para maior variedade de serviços ecossistêmicos possíveis relacionados à dispersão de sementes em áreas naturais, enquanto os menores valores desses índices foram encontrados em áreas antropizadas. Um maior número de espécies distintas com menor proximidade taxonômica durante a estação seca, em contraste com um alto número de indivíduos observados na estação chuvosa, indica que existe uma maior gama de possíveis serviços ecossistêmicos oferecidos pelas aves frugívoras no período mais seco do ano, enquanto no período de maior pluviosidade os ecossistemas apresentaram maior capacidade suporte.

The risks of introduction of the Amazonian palm Euterpe oleracea in the Atlantic rainforest / Os riscos da introdução da palmeira amazônica Euterpe oleracea na Floresta Atlântica

Abstract The introduction of a species may alter ecological processes of native populations, such as pollination and dispersal patterns, leading to changes in population structure. When the introduced and the native species are congeners, interference in pollination can also lead to hybridization. We aimed to understand the ecological aspects of Euterpe oleracea introduction in the Atlantic forest and the possible consequences for the conservation of the native congener Euterpe edulis. We analysed the population structure of palm populations, including hybrids, and observed the interaction with frugivorous birds of both palm species after E. oleracea introduction. We observed that E. edulis had significantly lower density and a smaller number of seedlings when occurring with E. oleracea. Native and introduced Euterpe species shared nine frugivorous bird species. E. oleracea and hybrids had dispersed outside the original planting area. Consequently, the risks of introduction of E. oleracea may mostly be related to the disruption of interactions between E. edulis and frugivorous birds and the spontaneous production of hybrids. Finally, the cultivation of E. oleracea and hybrids in Atlantic rainforest could affect the conservation of the already endangered E. edulis.

Resumo A introdução de uma espécie pode alterar processos ecológicos de populações nativas, tais como padrões de polinização e dispersão, levando a mudanças na estrutura populacional. Quando espécies introduzidas e nativas são congêneres, a interferência na polinização pode levar também à hibridização. Nossos objetivos foram entender os aspectos ecológicos da introdução de Euterpe oleracea na Floresta Atlântica e as possíveis consequências sobre a conservação da congênere nativa Euterpe edulis. Para isso, analisamos a estrutura populacional, incluindo híbridos, e observamos a interação de aves frugívoras com ambas as espécies de palmeira após a introdução de E. oleracea. Observamos que E. edulis apresentou densidade total e número de plântulas menores quando coocorrente com E. oleracea. As palmeiras congenéricas compartilharam nove espécies de aves frugívoras. E. oleracea e híbridos foram dispersos além da área original de plantio. Consequentemente, os riscos da introdução de E. oleracea podem estar principalmente relacionados com o possível deslocamento de interações entre E. edulis e aves frugívoras e com a produção de híbridos. Desta forma, o cultivo de E. oleracea e híbridos podem afetar a conservação da já ameaçada E. edulis.

Morphology predicts species' functional roles and their degree of specialization in plant-frugivore interactions.

Species' functional roles in key ecosystem processes such as predation, pollination or seed dispersal are determined by the resource use of consumer species. An interaction between resource and consumer species usually requires trait matching (e.g. a congruence in the morphologies of interaction partners). Species' morphology should therefore determine species' functional roles in ecological processes mediated by mutualistic or antagonistic interactions. We tested this assumption for Neotropical plant-bird mutualisms. We used a new analytical framework that assesses a species's functional role based on the analysis of the traits of its interaction partners in a multidimensional trait space. We employed this framework to test (i) whether there is correspondence between the morphology of bird species and their functional roles and (ii) whether morphologically specialized birds fulfil specialized functional roles. We found that morphological differences between bird species reflected their functional differences: (i) bird species with different morphologies foraged on distinct sets of plant species and (ii) morphologically distinct bird species fulfilled specialized functional roles. These findings encourage further assessments of species' functional roles through the analysis of their interaction partners, and the proposed analytical framework facilitates a wide range of novel analyses for network and community ecology.

Decadal persistence of frugivorous birds in tropical forest fragments of northern Paraná / Persistência de aves frugívoras após uma década em fragmentos florestais do norte do Paraná

Forest fragmentation is a major cause of loss of species. We evaluated the local extinction of medium-large frugivorous bird species in six forest fragments of northern Paraná: the Parque Estadual Mata dos Godoy (PEMG), the largest and most preserved forest fragment in the region, and five other fragments. Fixed-width point counts and line transects were conducted along trails in the PEMG for 10 days: from September 2010 to March 2011, and from August 2011 to November 2011. Avian surveys in each of the other forest fragments were made over four days from October to December 2011. We compared data with a previous census carried out 10 years earlier. No extinction events were recorded from the PEMG. However, the relative abundance of species significantly changed during the ten years between surveys. In all the other forest fragments at least two frugivorous bird species disappeared, and in some as many as seven. Protecting the PEMG is crucial for the maintenance of frugivorous bird populations in our studied landscape.

A fragmentação florestal é uma das principais causas da perda de espécies. Avaliamos a extinção local de aves frugívoras de médio e grande porte em seis fragmentos do norte do Paraná: o Parque Estadual Mata dos Godoy (PEMG), maior e mais preservado remanescente florestal da região, e outros cinco fragmentos. Foram realizadas amostragens por pontos de escuta de distância limitada e por transecções no PEMG ao longo de 10 dias: entre setembro de 2010 e março de 2011, e entre agosto e novembro de 2011. Os outros cinco fragmentos foram amostrados ao longo de quatro dias entre outubro e dezembro de 2011. Os dados foram comparados com um levantamento prévio realizado há 10 anos. Não foram observadas extinções no PEMG. No entanto, foram observadas alterações significativas na abundância relativa das espécies em dez anos (Wilcoxon Signed-Rank). Nos outros fragmentos florestais verificou-se o desaparecimento de pelo menos duas espécies, sendo que a variação foi de duas a sete espécies. A proteção do PEMG parece ser crucial para a manutenção das populações de aves frugívoras na paisagem estudada.

Bird frugivory and seed germination of Myrsine umbellata and Myrsine lancifolia (Myrsinaceae) seeds in a cerrado fragment in southeastern Brazil / Frugivoria e germinação de sementes de Myrsine umbellata e Myrsine lancifolia (Myrsinaceae) por aves em um fragmento de Cerrado no sudeste do Brasil

Birds are known to be important dispersers of plants, since the passage of seeds through the digestive tract often has a positive influence on germination percentage and speed. In this study, proportions of germination in different substrates were compared between Myrsine (Myrsinaceae) seeds collected manually and those ingested by birds. The guilds of birds that fed on M. umbellata and M. lancifolia were identified and comprise 24 and 12 species, respectively. A higher germination proportion was found among seeds defecated by birds and sowed in the study area. The study also found differences between the guilds of frugivores in both synchronopatric species. Therefore, we suggest that M. umbellata and M. lancifolia are important food sources by birds that play a positive influence for enhance germination of Myrsine.

As aves são reconhecidamente importantes agentes dispersores de plantas, uma vez que a passagem da semente pelo trato digestório muitas vezes interfere positivamente na porcentagem e velocidade de germinação de sementes. No presente estudo, as porcentagens de germinação, em diferentes substratos, foram comparadas entre sementes ingeridas por aves e sementes não-ingeridas (coletadas manualmente) de Myrsine (Myrsinaceae). A guilda de aves que se alimentou de M. umbellata e M. lancifolia foi identificada com 24 e 12 espécies, respectivamente. Verificou-se maior porcentagem de germinação nas sementes defecadas por aves, que foram semeadas em solo da área de estudo. Além disso, constataram-se diferenças nas guildas de frugívoros entre as duas espécies sincronopátricas. Portanto, nós sugerimos que M. umbellata e M. lancifolia são importantes fontes alimentares para aves que têm uma influência positiva para o aumento na germinação de Myrsine.

Influence of social status on individual foraging and community structure in a bird guild.

We investigated the influence of social interactions on individual foraging behavior and community structure of frugivorous birds in southern Costa Rica. Detailed observations of large, heterospecific feeding assemblages at fruiting trees revealed the existence of an interspecific dominance hierarchy, largely consistent with body and bill size. Social status influenced access to food in several ways. First, subordinate species were interrupted more and tended to have shorter foraging bouts than dominant species (n > 1.000 abouts). Second, analysis of over 7,000 videotaped head movements showed that subordinate species spent a smaller fraction of their foraging bouts actually feeding (as opposed to looking about) than did dominants. Third, when many birds were in a tree simultaneously, the foraging bouts of subordinate species were shortened; this effect was less pronounced or absent for species higher in the dominance hierarchy. Fourth, subordinate species foraged less frequently in mixed-species assemblages than did dominant species. Finally, subordinate species fed disproportionately more in the late afternoon at fruiting trees. The influence of social status appeared to manifest itself at the community level. The species composition of foraging assemblages was compared at isolated fruiting trees situated in an agricultural landscape near to (< 0.5 km) and far from (> 6 km) a large tract of primary forest. Whereas the full complement of avian frugivores foraged at the near trees, visitors to the far trees were predominantly of high social status. We discuss reasons why high social status and associated traits might confer an advantage in exploiting human-dominated habitat.