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.

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.

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 / 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.

Modelación del efecto de la reproducción colonial de Bubulcus ibis (Aves: Ardeidae) en el flujo de biomasa y energía de los manglares costeros

Introducción: Las colonias de aves zancudas alcanzan miles de nidos densamente agrupados, que influyen marcadamente sobre las características del suelo o el agua que las rodea por un efecto de hiperfertilización. Esto provoca la acumulación nociva de compuestos nitrogenados, alterando la química del sustrato y produciendo defoliación y muerte de la vegetación. El impacto de estas colonias en los manglares de Cuba no se ha evaluado, por las dificultades logísticas que implica y la complejidad de sus procesos. Objetivo: En el presente trabajo se realizó la estimación de las cantidades de biomasa, energía y nutrientes movilizados en una colonia de Bubulcus ibis, durante una etapa de cría, a través de un modelo bioenergético de dinámica de sistemas. Métodos: Se emplearon 29 variables primarias, 3 ecuaciones bioenergéticas y la ecuación de crecimiento postnatal de esta especie, implementadas en el programa STELLA 9.1.3. De la interacción de estas variables se obtuvieron: la energía requerida por ciclo de reproducción, la biomasa consumida y los nutrientes depositados en la colonia. Se realizó un análisis de sensibilidad y un análisis de incertidumbre para explorar las variables que más influencia tienen sobre los resultados. El modelo fue validado mediante la consistencia en las unidades, la prueba de valores extremos y la comparación con valores registrados en la literatura. Finalmente, se simularon escenarios de disturbios que pueden afectar a una colonia real. Resultados: Según el modelo, para el crecimiento cada pichón requiere de 10 219.2 kcal totales. La colonia debe invertir en total 6.71x106 kcal, lo que representa un consumo cercano a 2.2 toneladas de presas en una etapa de cría. Debido a este consumo, los nutrientes depositados en la colonia mediante las excretas estuvieron compuestos de 49 kg de nitrógeno, 7 kg de fósforo y 56 kg de calcio. Según el análisis de sensibilidad, las variables que producen cambios más fuertes en el resultado son el número de adultos de la colonia y el tamaño medio de puesta. El análisis de incertidumbre mostró poca influencia de las variables seleccionadas sobre las variables respuesta. Los disturbios simulados más dañinos para la colonia fueron las afectaciones al reclutamiento y el aumento de la mortalidad de los pichones.

Introduction: The colonies of wading birds reach thousands of highly grouped nests, which have a marked influence on the characteristics of the soil or the water that surrounds them due to a hyperfertilization effect. This causes the harmful accumulation of nitrogen compounds altering the chemistry of the substrate and causing defoliation and death of vegetation. The impact of these colonies on the mangroves in Cuba has not been evaluated, due to the logistical difficulties involved and the complexity of their processes. Objective: Mathematical modeling is a useful tool in these situations, so in this work the estimation of the quantities of biomass, energy and nutrients mobilized in a colony of herons was carried out, through a bioenergetic model of system dynamics. Methods: We used 29 primary variables, 3 bioenergetic equations and the postnatal growth equation of this species, implemented in the STELLA 9.1.3 program. From the interaction of these variables, the energy required by the reproduction cycle, the biomass consumed and the nutrients deposited in the colony were obtained. A sensitivity analysis and an uncertainty analysis were carried out to explore the variables that have the most influence on the results. The model was validated by the consistency in the units, the test of extreme values and the comparison with values recorded in the literature. Finally, disturbances scenarios that can affect a real colony were simulated. Results: According to the model, each nestling require 10 219.2 kcal to growth. The colony must totally invest 6.71x106 kcal, which represents consumption close to 2.2 tons of dams. Due to this consumption, the nutrients deposited in the colony by the excreta were 49 kg of nitrogen, 7 kg of phosphorus and 56 kg of calcium. According to the sensitivity analysis, the variables that produce the strongest changes in the result are the number of adults in the colony and the average clutch size. The uncertainty analysis showed little influence of the variables selected on the response variables. The most harmful simulated disturbances for the colony were the affectations to the recruitment and the increase of the mortality of the nestlings.

Effect of temporal lakes on avifaunal composition at the Southeast of Isthmus of Tehuantepec, Oaxaca, Mexico / Efecto de las lagunas temporales sobre la composición de la avifauna al Sureste del Istmo de Tehuantepec, Oaxaca, México

Oaxaca hosts one of the greatest biodiversity in México, occupying first place in avian diversity compared to other regions of the country. However, the area is undergoing serious problems such as high deforestation rates, soil erosion and over exploitation and extinction of species. These factors have all contributed to the current loss of biodiversity. Also, biological inventories are still incomplete. One of the least explored sites is the semiarid zone of Tehuantepec isthmus, around the locality of Santa Maria del Mar, Oaxaca, México. The area includes floodable grasslands, mangrove areas and dry forest, providing a range of potential habitats for different species. Our objective was to evaluate the effect of temporal lakes on spatial and temporal composition of the avifauna in Santa Maria del Mar, in order to generate information regarding this group within the region and the state, and to understand the importance of flood areas for resident and transitory birds. We conducted 12 avifauna surveys between July 2006 and June 2008, and established two transects of 2km length in each of four habitat types (beach, grassland, dry forest, and mangrove). We found a total of 75 species, corresponding to 16 orders and 30 families. Within an area of 26km², we significantly found 10.1% of the total number of bird species recorded for the entire state, and 6.6% of the total reported in Mexico. The families most represented were: Ardeidae, Laridae and Scolopacidae. Over the entire study period, dry forest was the most diverse habitat; followed by mangrove, grassland and the beach. Of all the species recorded, 38.6% were found at the edge or in the temporal lakes. We found a significant difference in species composition between seasons in the grassland, but no difference in the other habitats. Our results showed a significant effect of temporary lakes on avian diversity during the wet season; it also demonstrated the importance of grassland conservation given its relevance for presence of waterbirds. We suggested a continued and more intense monitoring; and proposed the designation of the area as an important Conservation Bird Area (AiCA).

Oaxaca alberga una biodiversidad de las más grandes en México, ocupando el primer lugar en diversidad de aves si se le compara con otras regiones del país. Sin embargo, el área sufre serios problemas tales como altas tasas de deforestación, erosión de suelo y sobre explotación y extinción de especies. Todos estos factores han contribuido con la actual pérdida de diversidad biológica. Además, los inventarios biológicos aún están incompletos. Una de las zonas menos exploradas es la parte semiárida del istmo de Tehuantepec, en los alrededores de la localidad de Santa María del Mar, Oaxaca, México. El área incluye pastizales inundables, áreas de manglar y de selva seca, y provee de una gama de hábitat potenciales para diversas especies. Nuestro objetivo fue evaluar el efecto de las lagunas temporales en la composición espacial y temporal de la avifauna en Santa María del Mar, con el propósito de generar información relacionada con este grupo dentro de la región y del estado, además de comprender la importancia de las áreas inundables para las aves residentes y migratorias. Entre julio 2006 y junio 2008 realizamos 12 monitoreos de la avifauna, y establecimos dos transectos de 2km de longitud para cada uno de los cuatro tipos de hábitat (playa, pastizal, selva seca y manglar). Encontramos un total de 75 especies, correspondendiendo a 16 órdenes y 30 familias. Dentro de un área de 26km², de manera significativa registramos el 10.1% del total de aves registradas para todo el estado y el 6.6% del total de especies registradas para México. Las familias mejor representadas fueron: Ardeidae, Laridae y Scolopacidae. Para todo el periodo de estudio, la selva seca fue el hábitat más diverso, seguido por el manglar, el pastizal abierto y la playa. Del total de especies registradas, el 38.6% se encontraron en el borde o dentro de lagunas temporales. Encontramos una diferencia significativa en la composición de especies entre temporadas en el pastizal, pero no se encontró diferencia entre el resto de los hábitat. Nuestros resultados muestran un efecto significativo de las lagunas temporales sobre la diversidad de la avifauna durante la temporada lluviosa; también evidencian la importancia de la conservación de los pastizales, dada su relevancia para la presencia de aves acuáticas. Sugerimos realizar un monitoreo continuo e intensivo, y proponemos que la zona sea designada como un área de importancia para la Conservación de las Aves (AiCA).

Community composition of aquatic birds in lakes of Bangalore, India.

Observations were made on the occurrence, abundance, richness, and diversity of waterbirds in 15 major lakes in Bangalore city during 2008 - 2009. During the study period 35 species of aquatic birds were recorded. The number of aquatic bird species recorded at various lakes ranged from 23 to 35. The percent abundance of waterbirds recorded in the study lakes ranged from 2.46 to 21.49 and it was significantly different (p<0.05). The diversity and species evenness of waterbirds in the lakes ranged from 2.07 to 3.16 and 0.32 to 0.76, respectively. There was a significant difference (p<0.05) in the diversity and species evenness of waterbirds among different lakes. Species richness of the bird population ranged from 2.89 to 4.01 in the different study lakes and it was not significantly different (p>0.05). There was a variation in number of waterbird species recorded during summer, monsoon and winter seasons. Of the 35 waterbird species, Bubulcus ibis showed cent percent frequency, whereas less frequently (4.44%) observed species was Anas platyrhynchos. Among various waterbird species, Bubulcus ibis, Fulica atra, Tringa hypoleucos, Motacilla maderaspatensis, Phalacrocorax niger, Egretta garzetta, Charadrius dubius, Ardeola grayji, Halcyon smyrnensis and Motacilla alba were frequently encountered in most of the study lakes.

Waterbirds and human-related threats to their conservation in Laguna Cuyutlán, Colima, México

Laguna Cuyutlán, the only large wetland in a span of 1 150 km along the Pacific coast of México, has been neglected as to its importance for waterbird conservation. At least 25 waterbird species nest there, with some of their colonies being very relevant, and at least 61 waterbird species use the lagoon during their nonbreeding season. This lagoon has been subject to several structural modifications, including levees and artificial channels which connect it to the sea, while water supply from continental sources has diminished, although its role has not been assessed yet. Salt extraction and artisanal fishery, the main economic activities, do not seem to pose a threat to waterbirds. Among potential threats to this acquatic ecosystem, are the raw sewage discharges that exist near urban areas, and pesticides from the surrounding agricultural lands might reach the lagoon. Seemingly, the most serious threat comes from waterway development in connection with a re-gasification plant to be built, and planned future port expansion, which could potentially increase water levels and alter important habitats for nesting and foraging. We recommend that: the area be declared an Important Bird Area; the development of the re-gasification plant and future port includes a levee to prevent alterations in water level in the remaining sections of the lagoon; supply of exogenous chemicals and waste products be prevented and monitored; alleged benefits from water interchange between the lagoon and the sea through artificial channels should be re-evaluated; and the role of fresh water supplies to the lagoon should be paid attention to. Rev. Biol. Trop. 57 (1-2): 1-12. Epub 2009 June 30.

Laguna Cuyutlán, el único humedal grande a lo largo de 1 150 km del Pacífico mexicano, no ha sido considerado un ecosistema natural importante para la conservación de aves acuáticas. Cuando menos 25 especies de aves acuáticas anidan ahí, y al menos 61 especies de aves acuáticas la usan fuera de la temporada reproductiva. Esta laguna ha sufrido varias modificaciones estructurales, y el aporte de agua dulce ha disminuido, sin que se conozcan sus consecuencias. La extracción de sal y la pesca artesanal, las principales actividades económicas, no parecen ser riesgo para las aves acuáticas. Entre los riesgos potenciales, están las aguas negras cerca de zonas urbanas y los plaguicidas de zonas agrícolas colindantes. Aparentemente, el riesgo más serio deriva del desarrollo marítimo asociado con una planta regasificadora a construirse pronto, y del desarrollo portuario futuro, que podrían incrementar los niveles de agua en la laguna y alterar los hábitats de las aves acuáticas. Recomendamos que: el área se declare como AICA; el desarrollo futuro incluya un dique para prevenir alteraciones en el nivel del agua en el resto de la laguna; el aporte de sustancias agroquímicas y aguas negras se monitoree; se reevalúen los supuestos beneficios del intercambio de agua entre la laguna y el mar por medio de canales artificiales; y se investigue científicamente los aportes de agua dulce a la laguna.

Notas sobre la avifauna del humedal santa maría del lago, cordillera oriental de los andes Colombianos / Notes on he birdd species of the santa maria del lago wetand, cordilleraa oriental of the Colombian andes mountains

Se presentan los resultados del inventario de la macrofauna observada (desde febrero 23 hasta mayo 31 del 2001) en Santa María del Lago, humedal netamente urbano, de los trece presentes en la ciudad de Bogotá durante su rehabilitación paisajística (recuperación del espejo de agua, revegetalización y reforestación). Los resultados incluyen una lista con las observaciones sobre el hábitat, actividad y frecuencia de tres especies de peces, una de anfibios, treinta y una de aves y tres de mamíferos, registradas en los diferentes muestreos mensuales con una intensidad de uno por semana. Dentro de la fauna del citado humedal, se resalta la presencia de los mamíferos Cavia porcellus (Caviidae), Oeomys speciosus (Muridae) y Olygoryzomys fulvescens (Muridae), la rana Hyla labialis (Hylidae) y los peces Eremophilus mutissii (Trichomycteridae) y Grundulus bogotensis (Characidae), que se consideraban desaparecidos del humedal. También se registran por primera vez para el humedal, nueve especies de aves (Anas platyrhynchos, Carduelis psaltria, Anser anser, Diglossa humeralis, Piranga olivacea, P. rubra, Rhamphocelus dimidiatus, Stelgidopteryx ruficollis, Vireo olivaceus), al igual que el pez exótico (C. auratus).

This article presents the results of the inventory of the observed macrofauna (from February 23rd to May 31st 2001) in Santa María del Lago, one of the thirteen present wetlands in Bogotá during its landscape rehabilitation (recovery of the water mirror, revegetation and reforestation). The results include a list with observations regarding the habitat, activity and frequency of 3 fish species, 1 amphibian, 31 bird and 3 mammal species, registered in the different monthly samplings with a weekly intensity. The fauna of the previously-mentioned wetland, includes mammals such as Cavia anolaimae (Caviidae), Oeomys speciosus (Muridae), and Olygoryzomys fulvescens (Muridae), the frog Hyla labialis (Hylidae) and the fish Eremophilus mutissii (Trichomycteridae) and rundulus bogotensis (Characidae) considered missing from the wetland. New species are also reported for first time in the wetland, 9 species of birds (Anas platyrhynchos, Carduelis psaltria, Anser anser, Diglossa humeralis, Piranga olivacea, P. rubra, Rhamphocelus dimidiatus, Stelgidopteryx ruficollis, Vireo olivaceus), and the exotic fish (C. auratus).

Estructura de la comunidad y asociación de las aves acuáticas con la heterogeneidad espacial del complejo lagunar Bahía Magdalena-Almejas, Baja California Sur, México / Community structure and association of waterbirds with spatial heterogeneity in the Bahia Magdalena-Almejas wetland complex, Baja California Sur, Mexico

Community structure and association of waterbirds with spatial heterogeneity in the Bahia Magdalena-Almejas wetland complex, Baja California Sur, Mexico. To test the hypothesis that spatial heterogeneity determines waterbird diversity in a coastal wetland, we compared waterbird density, diversity, and species composition among various habitats and landscapes units in Bahia Magdalena-Almejas, Baja California Sur, Mexico. Based on diversity patterns and bird distribution, we assessed the effect of coastal development on the waterbird community structure. To gather information on habitat features and waterbird populations we conducted waterbird censuses in 329 habitat segments along the internal coastline of the study area, from February 2002 to February 2003. We performed non-parametric analyses to test the null hypothesis of no diference on waterbird density, and diversity among landscape units and seasons. The species composition was evaluated using ordination techniques. Waterbird density was higher in winter and autumn in the three lagoons of the study area, particularly in the insular coast, sandy beach and dunes; it was higher in the few segments of antropic sustrate. Diversity was significantly higher in mangrove habitat along the peninsular coast, and in mangrove-dunes association on the insular coast. Although modification of coastal natural habitat and boat transit disturbance had no influence on waterbird density or diversity, the highest richness of waterbirds occurred in well preserved areas. Species composition analysis showed differences between Santo Domingo Channel and Magdalena Bay. Pelagic and mangrove habitat had a species composition difference higher than those associations in other habitats. Such differences in species assemblages by habitat and landscape units suggest that communities are structured according to the range of available natural resources in structurally complex habitats, and that dominant piscivorous waterbird species...

Para probar la hipótesis que la heterogeneidad espacial determina la diversidad de aves acuáticas en un humedal costero, comparamos la densidad, diversidad y composición de especies de aves acuáticas entre habitats y otras unidades de paisaje del complejo Bahía Magdalena-Almejas, Baja California Sur, México. Se realizaron censos de aves acuáticas en 329 segmentos de habitat de la línea de costa interna del complejo lagunar, desde febrero 2002 hasta febrero 2003. La densidad de aves fue mayor en invierno y otoño en las tres lagunas del área de estudio; de las zonas, la densidad fue mayor en la costa insular; y de los habitats en playa arenosa y dunas pero en los pocos segmentos de sustrato antrópico la densidad fue alta. La diversidad fue significativamente mayor en otoño; en Canal Santo Domingo; en la costa peninsular; y de los habitats en manglar-dunas y manglar. La modificación del habitat natural costero y el disturbio por tránsito de embarcaciones no tuvieron influencia en la densidad o diversidad de aves acuáticas, pero la riqueza acumulada mayor ocurrió en las costas bien conservadas y sin disturbio. El análisis de la composición de especies mostró diferencias entre las asociaciones de Canal Santo Domingo y Bahía Magdalena. El ambiente pelágico y el manglar tuvieron diferencia mayor en la composición de especies con respecto a las asociaciones de los demás habitats, tales diferencias en elencos de especies por habitat sugieren que la comunidad de aves está estructurada de acuerdo a los recursos naturales disponibles de las lagunas, zonas y habitats, en relación con la complejidad estructural de las unidades de paisaje. Las condiciones ecológicas del complejo lagunar ocasionan que las aves acuáticas piscívoras sean el grupo dominante de esta comunidad.

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 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.