Habitat mosaic and understory bird communities in Mexican cloud forest

Cloud forest is one of the most threatened ecosystems in Mexico and is important for its high biological diversity and for the ecological services that it provides. The Mexican cloud forests (CF) have been fragmented as a result of anthropogenic activities and deforestation. The south of Mexico contains almost 30% of the country's cloud forest, only a small proportion of which is protected in nature reserves. Conservation effort needs to be focused on the ecological value of agroecosystems that surround nature reserves. The study areas are located in the south of Mexico. Two are in the El Triunfo biosphera reserve in la Sierra Madre de Chiapas, and one is located in the central Region Mountains of Veracruz. The coffee is cultivated in transitional areas between natural forest and adjoining land systems. Based on the type of management, the structure and vegetation, it is possible to distinguish five main coffee production systems: two traditional shaded agroforests (with native trees), one commercially oriented polyspecific shaded system (where several fruit trees are used as shade), and two "modern" systems shaded (Inga) and unshaded monocultures (sun coffee). This research attempts to explain the effects of cloud forest patches (natural forest and coffee plantations) on bird diversity.Bird communities have been surveyed in 4 habitat types by point counts and mist-net techniques. The surveys were taken across a gradient from extensive primary and relatively undisturbed forest to intensive agricultural land uses (coffee plantations). Patterns of bird populations (species richness, abundance, density and community composition) and patch characteristics (size, altitudinal range, and topographic complexity) were analysed over this gradient.Of a total of 4560 birds recorded in point counts, there were 294 species, 168 genera and 41 families. In the patches of CF, from a total of 256 bird species, 36 were migratory and 53 have some status of conservation. In the patches of coffee plantations from a total of 159 species, 49 were migratory and 52 were under some status of conservation. Forest habitats, including continuous and patch forests, and shade coffee plantations, are found to support the most species and individuals. Nearctic-Neotropical migratory species are most numerous in shade coffee. Bird communities in shade coffee (natural and Inga) are characterised by a higher proportion of frugivorous and nectarivorous species, than communities in native forests. Using mist-net techniques, a total of 105 species, 87 genera and 23 families of birds were captured in 1600 net/hours for all the habitats.The size of forest patch is the main characteristic affecting forest interior and generalist species. Decreasing forest patch sizes appears to have unfavourable effects on forest generalist birds and positive effects on forest border species. The bird species most sensitive to forest fragmentation are those species restricted to the forest interior. The species richness and abundance demonstrate that many human-altered habitats are potentially valuable for birds. Further conservation efforts in tropical areas need to give more attention to the significance of agricultural lands as wildlife habitats

Soaring Migratory Birds Avoid Wind Farm in the Isthmus of Tehuantepec, Southern Mexico

Funding: This research was made possible with funding from the World Bank to the Comisión Federal de Electricidad (CFE) for monitoring the environmental impacts of the wind farm. The funders of this study were the CFE. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Diversidad y estructura vegetal en un paisaje antropizado de La Venta, Juchitán, Oaxaca, México

Background and Aims: Human activities have changed the structure and composition of ecosystems. These activities can fragment the natural landscape. This heterogeneity could generate greater diversity that allows the maintenance of the basic functions of the ecosystem. An analysis of plant diversity in the area of La Venta, Oaxaca, is presented to infer how species can contribute to the conservation of biodiversity and maintaining the ecosystem functionality.Methods: Seven elements of the landscape were identified by satellite images: medium subperennifolious tropical forest (MSTF), deciduous forest (DF), DF secondary vegetation (DFSV), gallery forest (GF), vegetation strips (VS) and agricultural area (AGRO). Within these sites, indices of diversity α and β, similarity and indices of relative importance were calculated.Key results: A total of 303 taxons were recorded in the six elements of the anthropized landscape. Of these, 231 were identified up to species level, and 38 at genus level. The MSB was the element with the greatest richness with 131 species, while AGRO was the poorest with only 10 registered species. The patterns of composition, structure, richness and diversity reported in this study are consistent with what has been described for dry tropical forests.Conclusions: Each of the landscape elements described is probably playing an important role in biodiversity retention. On the one hand, elements such as the SMS and the SBC may be functioning as sources of food and shelter for species of flora and fauna most associated with conserved habitats, while the BG and the VF, on the other hand, may be contributing to the connectivity of the landscape, as they function as biological corridors.Antecedentes y Objetivos: Las actividades humanas han cambiado la estructura y composición de los ecosistemas. Estas actividades frecuentemente fragmentan el paisaje natural. La heterogeneidad que se genera puede propiciar una mayor diversidad que permita el mantenimiento de las funciones básicas del ecosistema. En este trabajo se presenta un análisis de la diversidad vegetal en la zona de La Venta, Oaxaca, para inferir cómo las especies pueden contribuir en la conservación de biodiversidad y que sean capaces de mantener la funcionalidad del ecosistema.Métodos: Con imágenes de satélites se identificaron seis elementos del paisaje: selva mediana subperennifolia (SMS), selva baja caducifolia (SBC), acahual de SBC (ASBC), bosque de galería (BG), franjas de vegetación (FV) y área agropecuaria (AGRO). Dentro de estos sitios se calcularon índices de diversidad α y β, similitud e índices de importancia relativa.Resultados clave: Se registró un total de 303 taxones de plantas vasculares en los seis elementos que comprenden el paisaje antropizado. De estos, 231 fueron identificados hasta nivel de especie y 38 a nivel de género. La SMS fue el elemento con mayor riqueza con 131 especies registradas mientras que AGRO fue la más pobre con sólo 10. Los patrones de composición, estructura, riqueza y diversidad reportados en este estudio concuerdan con lo descrito para los bosques tropicales secos.Conclusiones: Cada uno de los elementos del paisaje descritos probablemente estén jugando un papel importante en la retención de biodiversidad. Los elementos como la SMS y la SBC pueden estar funcionando como fuentes de alimentación y refugio de especies de flora y fauna más asociadas a hábitats conservados, mientras que el BG y las FV pueden estar contribuyendo a la conectividad del paisaje, al funcionar como corredores biológicos

Invasive Plant Species Driving the Biotic Homogenization of Plant-Frugivore Interactions in the Atlantic Forest Biodiversity Hotspot

Although biological invasions are a common and intensively studied phenomenon, most studies often ignore the biotic interactions that invasive species play in the environment. Here, we evaluated how and why invasive plant species are interconnected within the overall frugivory network of the Brazilian Atlantic Forest, an important global biodiversity hotspot. To do this, we used the recently published Atlantic Frugivory Dataset to build a meta-network (i.e., a general network made of several local networks) that included interactions between 703 native and invasive plant species and 331 frugivore species. Using tools derived from complex network theory and a bootstrap simulation approach, we found that the general structure of the Atlantic Forest frugivory network (i.e., nestedness and modularity) is robust against the entry of invasive plant species. However, we observed that invasive plant species are highly integrated within the frugivory networks, since both native and invasive plant species play similar structural roles (i.e., plant status is not strong enough to explain the interactive roles of plant species). Moreover, we found that plants with smaller fruits and with greater lipid content play a greater interactive role, regardless of their native or invasive status. Our findings highlight the biotic homogenization involving plant–frugivore interactions in the Atlantic Forest and that the impacts and consequences of invasive plant species on native fauna can be anticipated based on the characteristics of their fruits

Data from: Response of migrating raptors to an increasing number of wind farms

Data associated to the manuscript with the same name.  Dataset containing 1) total bird count per day during six consecutive autumn migratory seasons, 2) polar coordinates of soaring birds flight trajectories obtained through observations with marine radar, and 3) wind direction measured during the same six autumn seasons.<br><br><br

Ecomorphological structure of avian communities changes upon arrival of wintering species

Community composition reflects evolutionary and ecological processes such as diversification and species assortment. Communities are generally considered to be saturated, which means that the number of species is maximized and that regulatory mechanisms, such as interspecific competition, prevent the addition of new species. In the tropics, however, species numbers of local bird assemblages double up each winter after the arrival of migratory species, which suggests that a rearrangement of niches occurs. Here ecological space is defined by morphological traits that reflect the ecological position of species, to describe changes in the structure of local communities. We found that the average morphological distance between species was reduced, and the volume (the total extent of trait space) was expanded with the arrival of migrants, indicating that newcomers occupy the periphery and the interior of the available ecological space. Furthermore, with greater morphological differences between resident species, higher numbers of migratory species can take advantage of free space and potentially exploit unused resources due to their intermediate morphology. We highlight the differences in the attributes of resident versus migratory species that may allow both to he accommodated in the morphological space, and we suggest coexistence theory as a possible explanation for the co-occurrence of similar species. (C) 2017 Gesellschaft fur Okologie. Published by Elsevier GmbH. All rights reserved

Summary of the null model results.

<p>Ranges represent 95% of the number of intersections/km from 10,000 trajectories under the simulated scenarios or null models for the spring and fall seasons. Bold type indicates ranges that do not include the observed number of intersections/km (p<0.05).</p><p>*Not evaluated.</p

Different models or scenarios used to simulate the flight trajectories.

<p>Different models or scenarios used to simulate the flight trajectories.</p