Abundance of White-fronted Parrots and diet of an urban parrot assemblage (Aves: Psittaciformes) in a green Neotropical city

Peer reviewe

Ensambles de aves diurnas a través de un gradiente de perturbación en un paisaje en el sureste de México

In order to assess of a Mexican tropical landscape like birds shelter, in the 2008 we evaluated richness, abundance, distribution and foraging guilds of birds in eight landscape units, nested within two ecomosaics. Of 218 species identified, 207 were recorded during dry season and 119 in the rain season. Species composition differed between the two ecomosaics, (a) heterogeneous agriculture matrix and (b) rain forest remnant, and among their nested landscape units. Shannon-Wiener index was similar (from 3.20 to 4.44) among landscape units, and mean species richness varied from 76 to 118species, while avian communities were equally distributed (Pielou: 0.71 to 0.91). At the landscape scale, the two ecomosaics play complementary roles in maintaining high bird diversity, providing habitat for high value conservation species like Tinamus major, Crypturellus soui, Crax rubra, Amazona farinosa, Odonthophorus guttatus, Chondrohierax uncinatus, Platyrinchus cancrominus, Onycorhynchus coronatus and Manacus candei. Foraging guilds frequencies differ by landscape units. For example in pasturelandswith spare trees, perch hunters and cattle-associated birds were abundant, while insectivores gleaning from soil, bark and foliage were common into the forest. Species like Lipaugus unirufus, Pipramentalis and Shiffornis turdinus could be ecological indicators of conserved forest conditions while Sporophila americana, S. torqueola, Pitangus sulphuratus, Cyanocorax morio and Crotophaga sulcirostris favor disturbed native forest habitat. Current patterns of landscape management constitute a potential model of sustainable management for both agricultural production and bird conservation. However this management model is threatened by external and internal drivers of extensive cattle ranching, the abandonment of swidden systems and gradual extraction of wood from local forests.Con el objetivo de evaluar la diversidad de aves que se presentan en un paisaje del trópico mexicano, en el año 2008 se evaluó la riqueza, abundancia y distribución de las aves y sus gremios de forrajeo en ocho unidades del paisaje agrupadas en dos ecomosaicos. De las 218 especies identificadas, 207 estuvieron presentes en la estación seca y 119 en la de lluvias. Se encontró que la composición de avifauna difiere entre los ecomosaicos (a) matriz agropecuaria heterogénea y (b) bosque tropical perennifolio,así como entre las unidades de paisaje anidadas en ellos. La riqueza varió de 76 a 118 especies entre unidades del paisaje, mientras que el índice de diversidad de Shannon-Wiener resultó similar (de 3.20 a 4.44), y las comunidades de aves se distribuyeron equitativamente (Pielou: 0.71 a 0.91). En el paisaje se configura un escenario complementario entre ecomosaicos y una diversidad de aves muy alta, incluyendo especies importantes para la conservación como Tinamus major, Crypturellus soui, Crax rubra, Amazona farinosa, Odontophorus guttatus, Chondrohierax uncinatus, Platyrinchus cancrominus, Onycorhynchus coronatus y Manacus candei. Los gremios de forrajeo de aves se separan en función de las características ambientales de las unidades de paisaje por ejemplo, en los potreros con árboles dispersos predominan cazadoras desde percha y especies asociadas al ganado, mientras que en el bosquepredominan los insectívoros que buscan sus presas en el suelo, corteza y follaje. Algunas especies como Lipaugus unirufus, Pipra mentalis y Schiffornis turdinus pueden funcionar como indicadoras ecológicas del bosque conservado, mientras otras como Sporophila americana, S. torqueola, Pitangus sulphuratus, Myozetetes similis, Cyanocorax morio y Crotophaga sulcirostris lo son para el estado perturbado del bosque nativo. El paisaje actual conformado por remanentes de bosque y una matriz agropecuaria con arbolado, posibilita la conservación biológica de aves, constituyendo un modelo potencial para su refugio y manejo sustentable. Sin embargo, la expansión de la ganadería extensiva, el abandono del sistema de rotación milpa-acahual y la extracción gradual de madera del bosque en el ejido, pone en riesgo la diversidad de la avifauna en la zona de estudio.

Conservation of birds in fragmented landscapes requires protected areas

For successful conservation of biodiversity, it is vital to know whether protected areas in increasingly fragmented landscapes effectively safeguard species. However, how large habitat fragments must be, and what level of protection is required to sustain species, remains poorly known. We compiled a global dataset on almost 2000 bird species in 741 forest fragments varying in size and protection status, and show that protection is associated with higher bird occurrence, especially for threatened species. Protection becomes increasingly effective with increasing size of forest fragments. For forest fragments >50 ha our results show that strict protection (International Union for Conservation of Nature [IUCN] categories I–IV) is strongly associated with higher bird occurrence, whereas fragments had to be at least 175 ha for moderate protection (IUCN categories V and VI) to have a positive effect. This meta-analysis quantifies the importance of fragment size, protection status, and their interaction for the conservation of bird species communities, and stresses that protection should not be limited to large pristine areas

Estructura de tallas de la almeja Psoronaias crocodilorum (Unionidae) en la Reserva de la Biosfera Pantanos de Centla, México

We assessed population parameters in two populations of mussels, Psoronaias crocodilorum, in the San Pedrito River and the Naranjos River in the Centla Wetlands Biosphere Reserve (CWBR), Mexico. Samples were collected in May 2008, and we determined their density and conducted a morphometric study. For each sample, we measured water depth, temperature, salinity, pH, organic matter and sand, silt and clay percentage. The San Pedrito river bank had a surface of 1200.12 m2 vs. 562.00 m2 in Los Naranjos. Shell length in San Pedrito was 21.26 76.16 mm vs. 22.20 83.30 in Los Naranjos; the most frequent length in both sites was 58.71 60.11 mm. Shell weight averaged 87.43% of the mussels total weight. MV in San Pedrito was 219.41 g/m2 and 81.75 g/m2 in Los Naranjos. Density in San Pedrito was 22.90 org/m2 and 10.50 org/m2 in Los Naranjos. Texture in sediment was loamy sand with 30.17% organic matter in San Pedrito, and 27.43% in Los Naranjos. Physicochemical parameters and the proportion of sand, silt and clay were similar in both sites. None of the mussel banks had biological, ecological or economic features for a fishery, especially due to their low abundance.En dos poblaciones del bivalvo Psoronaias crocodilorum localizados en los ríos San Pedrito y Los Naranjos, en la Reserva de la Biosfera Pantanos de Centla México (RBPC), se evaluaron algunos parámetros poblacionales. Las muestras se recolectaron en mayo del 2008, determinándose la densidad, y la estructura de talla, además de la profundidad, la temperatura, salinidad, pH, materia orgánica y porcentaje de arena, limo y arcilla. El área del banco en San Pedrito fue de 1200.13 m2 y de 562.00 m2 para Los Naranjos. La longitud de la concha para San Pedrito fue de 21.26 a 76.16 mm y de 22.20 a 83.30 mm para Los Naranjos, con una mayor frecuencia de talla entre 58.74 y 60.10 mm para las dos sitios. El peso de la concha representó el 87.43% en promedio del peso total de la almeja. La masa visceral (MV) en el banco de San Pedrito fue de 219.41 g/m2 y de 81.75 g/m2 para Los Naranjos. La densidad en San Pedrito fue de 22.90 org/m2 y de 10.50 org/m2 en Los Naranjos. La textura del sedimento fue migajón-arenoso con 30.17 % de materia orgánica para San Pedrito y de 27.43% para Los Naranjos. Los parámetros fisicoquímicos y la proporción de arena, limo y arcilla fueron similares en ambos sitios

Walking a Supramolecular Tightrope: A Self-Assembled Dodecamer from an 8-Aryl-2′-deoxyguanosine Derivative

Guanosine quadruplexes (GQs) have emerged in recent years as key players in the development of promising functional nanostruc-tures.1 GQs are formed by the self-assembly of guanosine subunits into planar tetramers (G-tetrads) that stack on each other, assisted by the complexation of a metal cation such as K+ or Na+. Alternatively, GQs can also form via the folding of G-rich oligonucleotides (e.g., DNA, RNA) leading to monomeric, dimeric, and tetrameric structures via the association of one, two, or four oligonucleotides, respectively.1d,2 In the latter, the number of G-tetrads is primarily controlled by the sequence (intrinsic param-eter) of the oligonucleotide, whereas, in the former, such control can be primarily achieved by adjusting extrinsic parameters (e.g., concentration, temperature, solvent,3 the cation template,4 and/or its counteranion5). Controlling the molecularity via intrinsic parameters (i.e., structural information in the supramolecula

Birds and bioenergy within the americas: A cross‐national, social–ecological study of ecosystem service tradeoffs

Although renewable energy holds great promise in mitigating climate change, there are socioeconomic and ecological tradeoffs related to each form of renewable energy. Forest‐related bioenergy is especially controversial, because tree plantations often replace land that could be used to grow food crops and can have negative impacts on biodiversity. In this study, we examined public perceptions and ecosystem service tradeoffs between the provisioning services associated with cover types associated with bioenergy crop (feedstock) production and forest habitat‐related supporting services for birds, which themselves provide cultural and regulating services. We combined a social survey‐based assessment of local values and perceptions with measures of bioenergy feedstock production impacts on bird habitat in four countries: Argentina, Brazil, Mexico, and the USA. Respondents in all countries rated birds as important or very important (83–99% of respondents) and showed lower enthusiasm for, but still supported, the expansion of bioenergy feedstocks (48–60% of respondents). Bioenergy feedstock cover types in Brazil and Argentina had the greatest negative impact on birds but had a positive impact on birds in the USA. In Brazil and Mexico, public perceptions aligned fairly well with the realities of the impacts of potential bioenergy feedstocks on bird communities. However, in Argentina and the USA, perceptions of bioenergy impacts on birds did not match well with the data. Understanding people’s values and perceptions can help inform better policy and management decisions regarding land use changes

Conservation and human livelihoods at the crossroads : local needs and knowledge in the management of Arabuko Sokoke Forest

Arabuko Sokoke Forest is the largest remaining single block of indigenous dry coastal tropical forest in Eastern Africa. Households within a 5 km buffer zone depend heavily on the forest for their livelihood needs, and the pressure on forest resources is on the increase. In May 2015, 109 households were interviewed on resources they obtain from the forest, in terms of the self-reported level of monthly income. We found household income and farm size significantly positively correlated with benefits from the forest, highlighting the possible influence of household wealth in exploiting forest resources. A large proportion of households (32%) had limited knowledge of local birds, while human–bird conflict was reported by 44% of the households. While many households were keen to participate in conservation projects that maintain the forest, 44% had no knowledge of the forest management plan, and 60% of those interviewed had no idea of how forest zones were designated for particular activities. Drivers for local community participation in conservation projects appear to be sustainable income and fulfilment of basic household needs

Vocal Learning and Auditory-Vocal Feedback

Vocal learning is usually studied in songbirds and humans, species that can form auditory templates by listening to acoustic models and then learn to vocalize to match the template. Most other species are thought to develop vocalizations without auditory feedback. However, auditory input influences the acoustic structure of vocalizations in a broad distribution of birds and mammals. Vocalizations are dened here as sounds generated by forcing air past vibrating membranes. A vocal motor program may generate vocalizations such as crying or laughter, but auditory feedback may be required for matching precise acoustic features of vocalizations. This chapter discriminates limited vocal learning, which uses auditory input to fine-tune acoustic features of an inherited auditory template, from complex vocal learning, in which novel sounds are learned by matching a learned auditory template. Two or three songbird taxa and four or ve mammalian taxa are known for complex vocal learning. A broader range of mammals converge in the acoustic structure of vocalizations when in socially interacting groups, which qualifies as limited vocal learning. All birds and mammals tested use auditory-vocal feedback to adjust their vocalizations to compensate for the effects of noise, and many species modulate their signals as the costs and benefits of communicating vary. This chapter asks whether some auditory-vocal feedback may have provided neural substrates for the evolution of vocal learning. Progress will require more precise definitions of different forms of vocal learning, broad comparative review of their presence and absence, and behavioral and neurobiological investigations into the mechanisms underlying the skills.PostprintPeer reviewe

Integración latinoamericana 1980-1990, (hemerografía)

L a hemerografía que a continuación presentamos responde a la relevancia que el problema de la integración ha cobrado actualmente para los países de América Latina. Si bien no tiene un carácter exhaustivo, pretende ser una contribución a la reflexión sobre el tema