Widely distributed breeding populations of Canada warbler (Cardellina canadensis) converge on migration through Central America

Background To effectively conserve migratory species, the entire range encompassed by their annual life cycle needs to be considered. Most research on Nearctic-Neotropical migratory birds has focused on the breeding grounds resulting in a general lack of knowledge regarding the wintering and migratory periods. The Canada Warbler (Cardellina canadensis) has declined by 71% from 1970 to 2012, at a rate of 2.9% per year, and is listed as Threatened in Canada. As with most Nearctic-Neotropical migrants, conservation efforts outside the breeding range are limited by a poor understanding of migration routes and the connectivity between specific breeding and wintering populations. Results To determine migratory routes of multiple breeding populations of Canada Warblers, we directly-tracked individuals using light-level geolocators deployed at four sites across the breeding range, spanning approximately 43 degrees in longitude (Alberta, Manitoba and Québec, Canada, and New Hampshire, USA). Twenty-five geolocators with usable data were recovered from three sites and were analyzed using FlightR to determine fall migration routes (n = 18) and individual wintering sites (n = 25). Individuals from all breeding populations took a western fall migration route at the Gulf of Mexico; with 77.8% of birds funnelling into a narrow geographic space along the western side of the Gulf of Mexico (97°W-99°W). We found no evidence for population-specific, parallel migration routes. Most individuals (72%) overwintered in Colombia. The remaining individuals overwintered in Venezuela. Conclusions Our results demonstrate convergence of migratory routes around a migration barrier for individuals originating from widely distributed breeding areas. Further, we suggest the potential importance of habitat around the Gulf of Mexico during migration and Andean forest in Colombia as overwintering habitat for this threatened species. Future research should be directed at understanding how these areas are used by Canada Warblers

Metodología de selección de especies de arbolado para el sombreado urbano en la parte oriental de la cornisa Cantábrica

The mitigation of the Urban Heat Island is one of the biggest future challenges in cities due to climate change. One of the methods to achieve the cooling of urban spaces is the attenuation of solar radiation provided by the trees. In the present article, a methodology of selection of arboreal species is proposed for the improvement of thermal comfort in urbanized areas of the eastern part of the Cantabrian coast. Starting from a pre-selection of native species, a classification of various species suitable for shading is obtained, describing its main characteristics and its possible use scope according to the typology of urban space.La mitigación del efecto Isla de Calor es uno de los mayores retos del futuro en las ciudades debido al cambio climático. Uno de los métodos para conseguir el enfriamiento de los espacios urbanos es la atenuación de radiación solar proporcionada por el arbolado. En el presente artículo se plantea una metodología de selección de especies arbóreas para la mejora del confort térmico en zonas urbanizadas de la parte oriental de la cornisa cantábrica. Partiendo de una preselección de especies autóctonas, se obtiene una clasificación de diversas especies aptas para el sombreado describiéndose sus principales características y su posible ámbito de utilización en función de la tipología de espacio urbano

Methodology of selection of tree species for urban shading in the eastern part of the Cantabrian coast

The mitigation of the Urban Heat Island is one of the biggest future challenges in cities due to climate change. One of the methods to achieve the cooling of urban spaces is the attenuation of solar radiation provided by the trees. In the present article, a methodology of selection of arboreal species is proposed for the improvement of thermal comfort in urbanized areas of the eastern part of the Cantabrian coast. Starting from a pre-selection of native species, a classification of various species suitable for shading is obtained, describing its main characteristics and its possible use scope according to the typology of urban space

MOLLUSCS IN THE DIET OF THE CARIBBEAN LOBSTER PANULIRUS-ARGUS CRUSTACEA DECAPODA

Volume: 9Start Page: 127End Page: 14

Differential effects of post-fire habitat legacies on beta diversity patterns of saproxylic beetles in the boreal forest

Fire-generated mosaics of habitat legacies such as dead and dying trees are key structural components in boreal forest ecosystems that support diverse saproxylic beetles. Our study sought to elucidate the spatial pattern of community composition (beta diversity) of saproxylic beetles along gradients of post-fire habitat legacies (tree species composition, tree size [dbh], and burn severities) and geographical distance. For 2 y, we reared saproxylic beetles from 360 logs retrieved from 72 sites in burned forests. Tests were performed to explain the overall beta diversity (βsor) by partitioning it into its 2 components: the "species spatial turnover" due to species replacement (βsim) and the "richness-driven" beta diversity due to species richness differences (βrich)- Variations in tree species, tree size, and burn severity had significant effects on overall beta diversity (βsor) of saproxylic beetles; these effects varied according to the differential influence of these factors on the 2 distinct components of beta diversity. Tree composition had notable effects on species spatial turnover (βsim), for which saproxylic species composition differed between jack pine and black spruce, and it was more variable between jack pine sites than between black spruce sites. On the other hand, variation in tree size was primarily responsible for the richness-driven beta diversity component (βrich), which was highest between the smallest and largest dbh groups and lowest between largest and mid-sized trees. Similarly, richness-driven composition differed significantly across severity gradients and was highest across low to high severity and lowest between low-severity stands. Broader geographical distance per se did not affect compositional patterns of saproxylic beetles, yet the landscape context could have some effect. These results could have crucial implications for post-fire management, which also aims to efficiently conserve saproxylic beetles. The significant spatial turnover in saproxylic composition between black spruce and jack pine and the underlying host-tree specificity suggest that a mosaic of both tree species should be maintained in the landscape. The richness-driven beta diversity pattern along the tree size and severity gradients implies that it may be necessary to prioritize the most species-rich classes, such as larger trees with lower severity burns, but with qualifications to cater also for species displaying idiosyncratic distributions

Early avian functional assemblages after fire, clearcutting, and post-fire salvage logging in North American forests

Abstract Increased demand for timber, the reduction in the available timber resources, and more frequent and severe forest fires under a changing climate have increased the use of salvage logging in North American forests despite concerns regarding impacts on biodiversity and long-term forest productivity. We aimed to complement previous approaches that used bird species richness or individual abundance in salvage-logged habitats to assess the sustainability of this practice. We looked for commonalities in the taxonomic, functional, and phylogenetic components of bird assemblages among these three post-disturbance habitats across a broad geographic range. We compiled six North American datasets selected from primary and grey literature that documented species composition of avian assemblages in habitats after recent fire, post-fire salvage logging, and traditional logging. Our results revealed contrasting patterns of bird trait assemblage among burned, post-fire salvage, and traditionally logged habitats. In salvage-logged habitats, taxonomic diversity, functional diversity, and functional and phylogenetic redundancy were significantly lower than in both burned and traditionally logged habitats. The frequency of insectivores was significantly lower after salvage logging than after both fire and traditional logging. These findings suggest that cumulative disturbances have a negative effect on early assembly of bird communities. The outcomes of this study encourage further assessments, at landscape level, of salvage logging intensity, burn size, and fire severity on bird functional structure to better plan for their conservation. Résumé La demande accrue de bois, la réduction des ressources ligneuses disponibles, les feux de forêt plus sévères et plus fréquents dans le contexte du changement climatique ont favorisé le recours à la coupe de récupération dans les forêts d’Amérique du Nord malgré les inquiétudes en ce qui a trait aux impacts sur la biodiversité et la productivité à long terme de la forêt. Nous avions pour objectif de compléter les approches précédentes qui ont utilisé la richesse ou l’abondance de chaque espèce d’oiseaux dans les habitats engendrés par la coupe de récupération pour évaluer la durabilité de cette pratique. Nous avons cherché des points communs dans les composantes taxonomique, fonctionnelle et phylogénétique des assemblages d’oiseaux entre trois habitats engendrés par cette perturbation à travers une vaste étendue géographique. Nous avons compilé six jeux de données nord-américaines choisies à partir de la littérature primaire ou grise qui a documenté la composition en espèces des assemblages aviaires dans les habitats issus d’un feu récent, d’une coupe de récupération après feu ou d’une coupe traditionnelle. Nos résultats révèlent différentes configurations de caractéristiques des assemblages d’oiseaux parmi les habitats brûlés, récupérés après feu ou exploités de façon traditionnelle. Dans les habitats issus d’une coupe de récupération, la diversité taxonomique, la diversité fonctionnelle, la redondance fonctionnelle et phylogénétique étaient significativement plus faibles que dans les habitats issus d’un feu ou d’une exploitation traditionnelle. La fréquence des insectivores était significativement plus faible après une coupe de récupération qu’après un feu ou une exploitation traditionnelle. Ces résultats indiquent que des perturbations cumulatives ont un effet négatif sur les premiers assemblages des communautés d’oiseaux. Les résultats de cette étude encouragent à poursuivre l’évaluation des effets, à l’échelle du paysage, de l’intensité de la coupe de récupération, de la taille du brûlis et de la sévérité du feu sur la structure fonctionnelle des oiseaux pour mieux planifier leur conservation

Contribution of unburned boreal forests to the population of black-backed woodpecker in eastern Canada

Black-backed woodpecker is known to be a disturbance-associated species, being more abundant in disturbed forest stands than in undisturbed habitats, but its demography and population dynamic still need to be clarified. The present study was conducted in central Quebec within coniferous forests shaped largely by timber harvest and wildfire. The objectives were to compare the age composition of breeding black-backed woodpeckers, nest survival rate and productivity in both disturbed and undisturbed habitats (respectively recently burned and unburned habitats). In addition, we evaluated the general productivity of both habitat types in a simulated boreal landscape. There was a positive relationship between nest age and daily survival rates. Older woodpeckers were the most abundant breeders in unburned habitats and younger birds in oneyear-old burns. Although nests in recently burned forests produced more nestlings per successful nest, our simulation of a boreal forest landscape showed that unburned habitat produced about two-thirds more fledglings per year than burned habitat. Globally, unburned habitat may provide woodpeckers more temporally stable resources. Population dynamics of the black-backed woodpecker, at least in our study area, may be explained by resource pulse interactions where populations benefit opportunistically from short-term high-quality habitat, and rely on unburned habitats for long-term persistence