Rainy cycles in South America as a driver for the breeding of the Black Skimmer (Rynchops niger) and the Large-billed Tern (Phaetusa simplex) (Aves, Charadriiformes)

The Black Skimmer (Rynchops niger) and the Large-billed Tern (Phaetusa simplex) are two migratory waterbirds that breed simultaneously on many river beaches in South America. Both are polytypic taxa with little information about the distribution and nonbreeding ("wintering") areas. Based on data from the literature, citizen science websites, fieldwork, and specimens housed in natural history museums, we revised the distribution of some of the main breeding colonies in South America, comparing it with continental rainy cycles to identify generalities about the role of precipitation seasonality on the defining intratropical migration routes of these species. Our data suggest that the seasonal precipitation cycle of South America directly influences the reproductive timing and distribution of both species, which is largely circumscribed by South America's rivers. After breeding on sandy beaches during the dry season, both species disperse in small groups or even individually ­ not in large flocks as seen in breeding areas ­ making it difficult to find general migration patterns during the rainy season. Nonetheless, individuals of both species tend to follow the course of the largest rivers of the continent and even alternative routes to disperse into several areas throughout South America during the nonbreeding season.(AU)

Richness, abundance and microhabitat use by Ardeidae (Aves: Pelecaniformes) during one seasonal cycle in the floodplain lakes of the lower Amazon River

The Amazon floodplains become periodically submerged as result of seasonal changes in the water levels throughout the year. These changes influence the availability of microhabitats and consequently the abundance of organisms in these ecosystems. In this study we investigated 1) how changes in the water level affect the richness and abundance of ardeid birds in the lowland floodplain lakes of the lower Amazon River, and 2) the microhabitats used by these birds throughout the seasonal cycle. Ten lakes were surveyed at each of the four phases of the seasonal cycle. In total, 3,280 individuals of 11 species were recorded. Of these, eight species occurred in the four phases, and three were observed in one or two phases. In the analysis including the entire family, there were more individuals in the phase with waters at lowest level and less in the phase that the water level was lowering. Many species were present throughout the seasonal cycle, suggesting that they might be resident species. However, their abundance varied throughut the cycle, suggesting that parts of their populations temporarily migrate elsewhere. The microhabitat that was most commonly used by most species at all phases of the seasonal cycle, with the excetions noted below, was aquatic macrophytes, suggesting that ardeid birds have a strong preperence for this kind of habitat. Three species - Egretta caerulea (Linnaeus, 1758), Nycticorax nycticorax (Linnaeus, 1758) and Bubulcus ibis (Linnaeus, 1758) - preferred other microhabitats at some phase of their seasonal cycle. The present study shows that the floodplain lakes of the lower Amazon River are richer in ardeid bird species than other areas of the Amazon biome and other biomes in Brazil. The fact that we found rare species in our study and that they depend on aquatic macrophytes demonstrates the importance of conserving the floodplain lakes of the lower Amazon River.

Richness, abundance and microhabitat use by Ardeidae (Aves: Pelecaniformes) during one seasonal cycle in the floodplain lakes of the lower Amazon River

The Amazon floodplains become periodically submerged as result of seasonal changes in the water levels throughout the year. These changes influence the availability of microhabitats and consequently the abundance of organisms in these ecosystems. In this study we investigated 1) how changes in the water level affect the richness and abundance of ardeid birds in the lowland floodplain lakes of the lower Amazon River, and 2) the microhabitats used by these birds throughout the seasonal cycle. Ten lakes were surveyed at each of the four phases of the seasonal cycle. In total, 3,280 individuals of 11 species were recorded. Of these, eight species occurred in the four phases, and three were observed in one or two phases. In the analysis including the entire family, there were more individuals in the phase with waters at lowest level and less in the phase that the water level was lowering. Many species were present throughout the seasonal cycle, suggesting that they might be resident species. However, their abundance varied throughut the cycle, suggesting that parts of their populations temporarily migrate elsewhere. The microhabitat that was most commonly used by most species at all phases of the seasonal cycle, with the excetions noted below, was aquatic macrophytes, suggesting that ardeid birds have a strong preperence for this kind of habitat. Three species - Egretta caerulea (Linnaeus, 1758), Nycticorax nycticorax (Linnaeus, 1758) and Bubulcus ibis (Linnaeus, 1758) - preferred other microhabitats at some phase of their seasonal cycle. The present study shows that the floodplain lakes of the lower Amazon River are richer in ardeid bird species than other areas of the Amazon biome and other biomes in Brazil. The fact that we found rare species in our study and that they depend on aquatic macrophytes demonstrates the importance of conserving the floodplain lakes of the lower Amazon River.(AU)

Genetic diversity and evidence of recent demographic expansion in waterbird populations from the Brazilian Pantanal

The present study determined nuclear and mitochondrial (mtDNA) levels of genetic variability and phylogeographic patterns in breeding populations of Roseate Spoonbill (N = 57), Wood Stork (N = 89), and Jabiru Stork (N = 30), sampled in the Brazilian Pantanal. These species were selected since they are bioindicators of wetlands’ health and are threatened in other parts of their distribution. As they are in close association with this ecosystem, they are appropriate for studying the effects of Pleistocene climatic changes on their demographic patterns. Levels of nuclear genetic diversity in Pantanal populations were not significantly different from those of other populations throughout the American continent, where they are considered threatened or of special concern. Reduced levels of mtDNA genetic diversity were observed in the Central American population of Jabiru Stork in comparison to the Pantanal population. Recent demographic expansion in the Pantanal was markedly evidenced by unimodal patterns of mismatch distribution and Fu’s Fs neutrality test in these three species. We hypothesize that the average time of population expansion (between 30,843 and 14,233 years before present) is associated to responses of these birds’ populations to paleoclimatic changes in these wetlands during the last glaciation period. We recommend special conservation efforts with the Jabiru Stork populations, a genetic monitoring program based on mtDNA, and an ecological characterization of these waterbirds species throughout their distribution range.

O presente estudo determinou níveis de variabilidade nuclear e mitocondrial (DNAmit) e padrões filogeográficos de populações reprodutivas de colhereiro (N = 57), cabeça-seca (N = 89) e tuiuiú (N = 30) do Pantanal brasileiro. Estas espécies foram selecionadas porque são bioindicadoras da integridade das áreas alagáveis e se encontram ameaçadas em outras partes da sua área de distribuição. Devido à sua estreita associação com esse tipo de ecossistema, seu estudo permite verificar os efeitos das mudanças climáticas do Pleistoceno nos seus padrões demográficos. Níveis de diversidade genética nuclear nas populações pantaneiras não diferiram significativamente dos encontrados em outras populações ao longo do continente americano onde são consideradas ameaçadas ou como de especial interesse para conservação. Níveis reduzidos de variabilidade genética DNAmit foram observados nas populações de tuiuiú da América Central, quando comparadas às populações do Pantanal. A expansão demográfica recente das três espécies no Pantanal ficou marcadamente evidenciada pelos padrões unimodais da distribuição das diferenças pareadas e pelo teste de neutralidade de Fs de Fu. Hipotetizamos que o tempo médio de expansão populacional (entre 30.843 e 14.233 anos antes do presente) está associado as respostas destas populações de aves às mudanças climáticas ocorridas nas áreas alagáveis durante o último período de glaciação. Recomendamos, esforços especiais na conservação das populações do tuiuiú, um programa de monitoramento genético baseado no DNAmit e a caracterização ecológica dessas espécies de aves aquáticas ao longo de suas áreas de distribuição.

Genetic diversity and evidence of recent demographic expansion in waterbird populations from the Brazilian Pantanal

The present study determined nuclear and mitochondrial (mtDNA) levels of genetic variability and phylogeographic patterns in breeding populations of Roseate Spoonbill (N = 57), Wood Stork (N = 89), and Jabiru Stork (N = 30), sampled in the Brazilian Pantanal. These species were selected since they are bioindicators of wetlands health and are threatened in other parts of their distribution. As they are in close association with this ecosystem, they are appropriate for studying the effects of Pleistocene climatic changes on their demographic patterns. Levels of nuclear genetic diversity in Pantanal populations were not significantly different from those of other populations throughout the American continent, where they are considered threatened or of special concern. Reduced levels of mtDNA genetic diversity were observed in the Central American population of Jabiru Stork in comparison to the Pantanal population. Recent demographic expansion in the Pantanal was markedly evidenced by unimodal patterns of mismatch distribution and Fus Fs neutrality test in these three species. We hypothesize that the average time of population expansion (between 30,843 and 14,233 years before present) is associated to responses of these birds populations to paleoclimatic changes in these wetlands during the last glaciation period. We recommend special conservation efforts with the Jabiru Stork populations, a genetic monitoring program based on mtDNA, and an ecological characterization of these waterbirds species throughout their distribution range.

O presente estudo determinou níveis de variabilidade nuclear e mitocondrial (DNAmit) e padrões filogeográficos de populações reprodutivas de colhereiro (N = 57), cabeça-seca (N = 89) e tuiuiú (N = 30) do Pantanal brasileiro. Estas espécies foram selecionadas porque são bioindicadoras da integridade das áreas alagáveis e se encontram ameaçadas em outras partes da sua área de distribuição. Devido à sua estreita associação com esse tipo de ecossistema, seu estudo permite verificar os efeitos das mudanças climáticas do Pleistoceno nos seus padrões demográficos. Níveis de diversidade genética nuclear nas populações pantaneiras não diferiram significativamente dos encontrados em outras populações ao longo do continente americano onde são consideradas ameaçadas ou como de especial interesse para conservação. Níveis reduzidos de variabilidade genética DNAmit foram observados nas populações de tuiuiú da América Central, quando comparadas às populações do Pantanal. A expansão demográfica recente das três espécies no Pantanal ficou marcadamente evidenciada pelos padrões unimodais da distribuição das diferenças pareadas e pelo teste de neutralidade de Fs de Fu. Hipotetizamos que o tempo médio de expansão populacional (entre 30.843 e 14.233 anos antes do presente) está associado as respostas destas populações de aves às mudanças climáticas ocorridas nas áreas alagáveis durante o último período de glaciação. Recomendamos, esforços especiais na conservação das populações do tuiuiú, um programa de monitoramento genético baseado no DNAmit e a caracterização ecológica dessas espécies de aves aquáticas ao longo de suas áreas de distribuição.

Assessment of anthropogenic-causing-agents act on waterbirds-diversity in the vicinity of Tarbela Dam, Indus River, Pakistan

Abstract Birds are among the best bio-indicators, which can guide us to recognize some of the main conservation concerns in ecosystems. Anthropogenic impacts such as deforestation, habitat degradation, modification of landscapes, and decreased quality of habitats are major threats to bird diversity. The present study was designed to detect anthropogenic causative agents that act on waterbird diversity in Tarbella Dam, Indus River, Pakistan. Waterbird censuses were carried out from March 2019 to February 2020 in multiple areas around the dam. A total of 2990 waterbirds representing 63 species were recorded. We detected the highest waterbird richness and diversity at Pehure whereas the highest density was recorded at Kabbal. Human activity impacts seemed to be the main factor determining the waterbird communities as waterbirds were negatively correlated with the greatest anthropogenic impacts. Waterbirds seem to respond rapidly to human disturbance.

Resumo As aves estão entre os melhores bioindicadores, o que pode nos orientar a reconhecer algumas das principais preocupações de conservação dos ecossistemas. Impactos antrópicos como desmatamento, degradação de habitat, modificação de paisagens e diminuição da qualidade dos habitats são as principais ameaças à diversidade de aves. O presente estudo foi desenhado para detectar agentes causadores antropogênicos que atuam na diversidade de aves aquáticas na Represa de Tarbella, rio Indus, Paquistão. Censos de aves aquáticas foram realizados de março de 2019 a fevereiro de 2020 em várias áreas ao redor da barragem. Um total de 2.990 aves aquáticas representando 63 espécies foi registrado. Detectamos a maior riqueza e diversidade de aves aquáticas em Pehure, enquanto a maior densidade foi registrada em Kabbal. Os impactos da atividade humana parecem ser o principal fator determinante das comunidades de aves aquáticas, uma vez que as aves aquáticas foram negativamente correlacionadas com os maiores impactos antrópicos. As aves aquáticas parecem responder rapidamente às perturbações humanas.

Assessment of anthropogenic-causing-agents act on waterbirds-diversity in the vicinity of Tarbela Dam, Indus River, Pakistan / Avaliação de agentes antropogênicos que agem na diversidade de aves aquáticas nas proximidades da Represa de Tarbela, rio Indus, Paquistão

Abstract Birds are among the best bio-indicators, which can guide us to recognize some of the main conservation concerns in ecosystems. Anthropogenic impacts such as deforestation, habitat degradation, modification of landscapes, and decreased quality of habitats are major threats to bird diversity. The present study was designed to detect anthropogenic causative agents that act on waterbird diversity in Tarbella Dam, Indus River, Pakistan. Waterbird censuses were carried out from March 2019 to February 2020 in multiple areas around the dam. A total of 2990 waterbirds representing 63 species were recorded. We detected the highest waterbird richness and diversity at Pehure whereas the highest density was recorded at Kabbal. Human activity impacts seemed to be the main factor determining the waterbird communities as waterbirds were negatively correlated with the greatest anthropogenic impacts. Waterbirds seem to respond rapidly to human disturbance.

Resumo As aves estão entre os melhores bioindicadores, o que pode nos orientar a reconhecer algumas das principais preocupações de conservação dos ecossistemas. Impactos antrópicos como desmatamento, degradação de habitat, modificação de paisagens e diminuição da qualidade dos habitats são as principais ameaças à diversidade de aves. O presente estudo foi desenhado para detectar agentes causadores antropogênicos que atuam na diversidade de aves aquáticas na Represa de Tarbella, rio Indus, Paquistão. Censos de aves aquáticas foram realizados de março de 2019 a fevereiro de 2020 em várias áreas ao redor da barragem. Um total de 2.990 aves aquáticas representando 63 espécies foi registrado. Detectamos a maior riqueza e diversidade de aves aquáticas em Pehure, enquanto a maior densidade foi registrada em Kabbal. Os impactos da atividade humana parecem ser o principal fator determinante das comunidades de aves aquáticas, uma vez que as aves aquáticas foram negativamente correlacionadas com os maiores impactos antrópicos. As aves aquáticas parecem responder rapidamente às perturbações humanas.

Invertebrate dispersal by waterbird species in neotropical wetlands

Abstract Endozoochory by waterbirds is particularly relevant to the dispersal of non-flying aquatic invertebrates. This ecological function exercised by birds has been demonstrated in different biogeographical regions, but there are no studies for the neotropical region. In this work, we identified propagules of invertebrates in faeces of 14 syntopic South American waterbird species representing six families, and hatched additional invertebrates from cultured faeces. We tested whether propagule abundance, species richness and composition varied among bird species, and between the cold and warm seasons. We found 164 invertebrate propagules in faecal samples from seven different waterbirds species, including eggs of the Temnocephalida and Notonectidae, statoblasts of bryozoans (Plumatella sp.) and ephippia of Cladocera. Ciliates (including Paramecium sp. and Litostomatea), nematodes and rotifers (Adineta sp. and Nottomatidae) hatched from cultured samples. Potential for endozoochory was confirmed for 12 of 14 waterbird species. Our statistical models suggest that richness and abundance of propagules are associated with bird species and not affected by seasonality. Dispersal by endozoochory is potentially important to a broad variety of invertebrates, being promoted by waterbirds with different ecological and morphological traits, which are likely to drive the dispersal of invertebrates in neotropical wetlands.

Resumo A endozoocoria promovida por aves aquáticas é particularmente relevante para a dispersão de invertebrados aquáticos não-voadores. Essa função ecológica exercida pelas aves tem sido demonstrada para diferentes regiões biogeográficas, porém, não existem estudos para a região neotropical. Neste trabalho nós identificamos propágulos de invertebrados encontrados em fezes de 14 espécies sintópicas de aves aquáticas da América do Sul, representando seis famílias de aves, e também invertebrados emergidos de amostras fecais cultivadas em laboratório. Testamos se a abundância, riqueza de espécies e composição de propágulos de invertebrados variavam entre as espécies de aves e entre estações. Nós encontramos 164 propágulos de invertebrados em amostras fecais de sete espécies de aves, incluindo ovos de Temnocephalida e Notonectidae, estatoblastos de briozoários (Plumatella sp.) e efípios de Cladocera. Ciliados (incluindo Paramecium sp. e Litostomatea), nematóides e rotíferos (Adineta sp. e Nottomatidae) eclodiram de amostras cultivadas. O potencial para endozoocoria foi confirmado para 12 das 14 espécies de aves aquáticas investigadas. Nossos modelos estatísticos sugerem que a riqueza e abundância de propágulos estão associadas às espécies de aves e não são afetadas pela sazonalidade. A dispersão por endozoocoria é importante para uma ampla variedade de invertebrados, sendo promovida por aves aquáticas com diferentes características ecológicas e morfológicas as quais provavelmente regulam a dispersão de invertebrados entre áreas úmidas neotropicais.

Invertebrate dispersal by waterbird species in neotropical wetlands / A dispersão de invertebrados por aves aquáticas na região neotropical

Abstract Endozoochory by waterbirds is particularly relevant to the dispersal of non-flying aquatic invertebrates. This ecological function exercised by birds has been demonstrated in different biogeographical regions, but there are no studies for the neotropical region. In this work, we identified propagules of invertebrates in faeces of 14 syntopic South American waterbird species representing six families, and hatched additional invertebrates from cultured faeces. We tested whether propagule abundance, species richness and composition varied among bird species, and between the cold and warm seasons. We found 164 invertebrate propagules in faecal samples from seven different waterbirds species, including eggs of the Temnocephalida and Notonectidae, statoblasts of bryozoans (Plumatella sp.) and ephippia of Cladocera. Ciliates (including Paramecium sp. and Litostomatea), nematodes and rotifers (Adineta sp. and Nottomatidae) hatched from cultured samples. Potential for endozoochory was confirmed for 12 of 14 waterbird species. Our statistical models suggest that richness and abundance of propagules are associated with bird species and not affected by seasonality. Dispersal by endozoochory is potentially important to a broad variety of invertebrates, being promoted by waterbirds with different ecological and morphological traits, which are likely to drive the dispersal of invertebrates in neotropical wetlands.

Resumo A endozoocoria promovida por aves aquáticas é particularmente relevante para a dispersão de invertebrados aquáticos não-voadores. Essa função ecológica exercida pelas aves tem sido demonstrada para diferentes regiões biogeográficas, porém, não existem estudos para a região neotropical. Neste trabalho nós identificamos propágulos de invertebrados encontrados em fezes de 14 espécies sintópicas de aves aquáticas da América do Sul, representando seis famílias de aves, e também invertebrados emergidos de amostras fecais cultivadas em laboratório. Testamos se a abundância, riqueza de espécies e composição de propágulos de invertebrados variavam entre as espécies de aves e entre estações. Nós encontramos 164 propágulos de invertebrados em amostras fecais de sete espécies de aves, incluindo ovos de Temnocephalida e Notonectidae, estatoblastos de briozoários (Plumatella sp.) e efípios de Cladocera. Ciliados (incluindo Paramecium sp. e Litostomatea), nematóides e rotíferos (Adineta sp. e Nottomatidae) eclodiram de amostras cultivadas. O potencial para endozoocoria foi confirmado para 12 das 14 espécies de aves aquáticas investigadas. Nossos modelos estatísticos sugerem que a riqueza e abundância de propágulos estão associadas às espécies de aves e não são afetadas pela sazonalidade. A dispersão por endozoocoria é importante para uma ampla variedade de invertebrados, sendo promovida por aves aquáticas com diferentes características ecológicas e morfológicas as quais provavelmente regulam a dispersão de invertebrados entre áreas úmidas neotropicais.