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A comprehensive review of the natural history of the Canary Islands stonechat Saxicola dacotiae in Spain.

The fit between life histories and ecological niche is a paradigm of phenotypic evolution, also widely used to explain patterns of species co-occurrence. By analysing the lifestyles of a sympatric avian assemblage, we show that species' solutions to environmental problems are not unbound. We identify a life-history continuum structured on the cost of reproduction along a temperature gradient, as well as habitat-driven parental behaviour. However, environmental fit and trait convergence are limited by niche filling and by within-species variability of niche traits, which is greater than variability of life histories. Phylogeny, allometry and trade-offs are other important constraints: lifetime reproductive investment is tightly bound to body size, and the optimal allocation to reproduction for a given size is not established by niche characteristics but by trade-offs with survival. Life histories thus keep pace with habitat and climate, but under the limitations imposed by metabolism, trade-offs among traits and species' realized niche.

Elevation gradients are associated with sharp environmental clines that play a crucial role in the phenotypic diversification of animal populations. In a variety of organisms, the reproductive output of females declines with elevation in parallel to the drop in environmental productivity and shortening of the breeding season. Little evidence is available on male traits associated with reproductive activities, such as territorial defence and signalling, which may decline because of the low economic defendability of resources and the selective advantage of investing in parental rather than mating (e.g. signalling, chasing intruders) effort in such conditions. Along a broad elevational gradient, we investigated variation in the intensity of territorial defence and sexual signalling in males of the water pipit Anthus spinoletta exposed to song playbacks simulating the territorial intrusion of a conspecific. We found that birds from the lower limits of the species distribution approached song stimuli more closely than those from the upper limits. Moreover, physically challenging songs (broad frequency bandwidths and fast trills) elicited a closer approach, and low elevation birds uttered songs ending with the broadest bandwidths. Other responses to the intrusion, such as the number of songs uttered or the latency to approach, exhibited seasonal or spatial variation irrespective of elevation. This study illustrates the decline of some trait associated with aggressive territorial behaviours during male-male conflicts along elevation, and points to the allocation in sexual signalling and motor constraints to signal production, as potential mechanisms underlying it.

In winter, foraging activity is intended to optimize food search while minimizing both thermoregulation costs and predation risk. Here we quantify the relative importance of thermoregulation and predation in foraging patch selection of woodland birds wintering in a Mediterranean montane forest. Specifically, we account for thermoregulation benefits related to temperature, and predation risk associated with both illumination of the feeding patch and distance to the nearest refuge provided by vegetation. We measured the amount of time that 38 marked individual birds belonging to five small passerine species spent foraging at artificial feeders. Feeders were located in forest patches that vary in distance to protective cover and exposure to sun radiation; temperature and illumination were registered locally by data loggers. Our results support the influence of both thermoregulation benefits and predation costs on feeding patch choice. The influence of distance to refuge (negative relationship) was nearly three times higher than that of temperature (positive relationship) in determining total foraging time spent at a patch. Light intensity had a negligible and no significant effect. This pattern was generalizable among species and individuals within species, and highlights the preponderance of latent predation risk over thermoregulation benefits on foraging decisions of birds wintering in temperate Mediterranean forests. © 2013 Villén-Pérez et al.

[EN] Aim To disentangle the subtleties of the relationship between the thermal environment and the distribution of wintering birds, at multiple spatial scales. Specifically, to analyze the relative influence of temperature on species distributions, its interaction with various thermal and non-thermal factors, and the context-dependence of these relationships (i.e., species, season and geographical location). Location Iberian Peninsula and Guadarrama Mountain range (central Spain). Methods I use observational and experimental field approaches to control for habitat structure, topography, food abundance and predation risk, from forest patches to landscape, regional and peninsular scales. Fieldwork is carried out with woodland passerines inhabiting mountain oakwoods of Quercus pyrenaica, and subtle variations in temperature and wind are precisely measured with data loggers. Main results and conclusions Wintering birds respond to natural variations in temperature at multiple scales, selecting the warmest forest patches to forage and the warmest mountain areas and peninsular regions to overwinter. However, temperature per se accounts for a relatively small proportion of the variation in species distribution patterns. Indeed, a sudden extreme drop in temperature is not enough to alter species abundances, or to promote their general redistribution to minimize wind chill. Other non-thermal environmental factors like vegetation structure, predation risk and availability of predictable food resources, seem to be more deterministic in driving winter species distribution than direct measurements of temperature. On the other hand, the influence of the thermal environment goes far beyond average temperature: minimum night temperature, incident sun radiation and altitude related with snow cover are key drivers of species distributions. The relative relevance of all these factors depends on the ecological scenario, varying across species, seasons and geographical locations. I concl, [ES] Objetivo: Desentrañar los pormenores de la relación entre el ambiente térmico y la distribución de aves invernantes a múltiples escalas espaciales. En concreto, analizar la influencia relativa de la temperatura en la distribución de especies, su interacción con varios factores térmicos y no térmicos, y cómo tales relaciones dependen del contexto ecológico (i.e., especies involucradas, estación del año y localización geográfica). Localización Península Ibérica y Sierra de Guadarrama (centro de España). Métodos: He utilizado tanto aproximaciones observacionales como experimentales de campo para controlar el efecto de la estructura del hábitat, la topografía, la abundancia de alimento y el riesgo de depredación, en escalas que varían desde el parche hasta el paisaje forestal, la región de Guadarrama y la Península Ibérica. El trabajo de campo se ha llevado a cabo con paseriformes forestales de robledales montanos de Quercus pyrenaica, y las variaciones de temperatura y viento se han medido de forma precisa y local con registradores de datos. Resultados y conclusiones principales: Las aves invernantes responden a variaciones naturales en la temperatura a múltiples escalas, seleccionando los parches forestales más cálidos para forrajear y las áreas de la sierra y de la península más cálidas para pasar el invierno. Sin embargo, la temperatura “per se” explica una proporción relativamente pequeña de la variación en los patrones de distribución de especies. De hecho, una caída extrema y repentina de la temperatura no es suficiente para alterar la abundancia de las especies, ni para promover su redistribución general hacia las áreas con una sensación térmica más alta. Otros factores ambientales como la estructura de la vegetación, el riesgo de depredación y la disponibilidad de fuentes predecibles de alimento, son más deterministas en la distribución invernal de especies que las medidas directas de temperatura. Por otro lado, la influencia del ambiente térmico va más al

Although energy is a major driver of global patterns of biodiversity and species distribution, the test of species-energy relationships needs further development using fine-grained approaches involving different functional groups of species and small geographical scales of known characteristics (habitat heterogeneity, food availability, direct measures of temperature). We carried out an experiment over a broad range of habitat structure and environmental conditions to disentangle the effects of two different energy measures on the small-scale variation of habitat use in winter: one directly related to food resources (manipulated food availability with artificial feeders), and another related to thermoregulatory costs (night temperature). The spatial variation in abundance of a guild of tree-gleaning birds wintering in montane Mediterranean oakwoods of Central Spain was positively related to both components of energy availability (temperature and food resources), even in these mild Mediterranean montane forest of southern Europe. Spatial variation in consumption of food from artificial feeders was negatively related to spatial variation in temperature. The influence of food availability on bird abundance was mediated by vegetation structure, with a lower influence in maturer oakwoods. This study highlights the important role of the energy-related factors, over habitat structure, in determining winter abundance of the studied tree-gleaning guild.

Due to the growing awareness of potential impacts of roads, managers demand well-designed studies about the implications of linear infrastructures on ecosystems. We illustrate the application of Before– During–After and Before–During–After-Control–Impact designs (BDA and BDACI) to assess effects of highway construction and operation using a population of great bustards (Otis tarda) as a model. Based on a time series of demographic and distribution data (1997–2009), we developed generalized additive models and classification trees to test the effect of road distance on bustard distribution, identify roadeffect distances and explore the seasonality of these effects. Two control zones were selected to test the changes between construction phases on productivity, and population trends using TRIM models. From the start of the road construction, great bustards tended to avoid close proximity to the highway (ca. 560–750 m threshold distance). The exclusion band was narrower during the breeding season. In addition, family groups were less tolerant to highway operation disturbances, as shown by their higher distance effect (ca. 1300 m). Population trends did not differ between impact and control zones during the construction. However, once the highway was in operation, bustard numbers declined gradually up to 50% in the impact zone, remained stable in the closest control zone, and increased in the zone located at the greatest distance from the highway. The effects on density of family groups were less evident. Our approach provides information relevant to great bustard conservation and suggests methods for obtaining information of interest to road managers, that could be applied to linear infrastructures with others species.

El ensayo explora la configuración del campo sociológico alrededor de la disputa sobre la pertinencia del canon clásico disciplinario. Se sigue este debate a partir de cuatro relevantes sociólogos: Jeffrey Alexander, Immanuel Wallerstein, Niklas Luhmann y R. W. Connell. Por medio de ellos se presentan algunos matices del asunto para, finalmente, esbozar vínculos entre el proceso de canonización de clásicos y la construcción del campo disciplinario.

[ES] Se analiza el estatus de conservación de todas las Aves de la Comunidad de Madrid utilizando parámetros ecológicos asociados con la valencia ecológica de las especies, la extensión de su área de distribución, sus preferencias de hábitat y las densidades máximas ecológicas en la región. Las especies menos ampliamente distribuidas en la C.A. de Madrid se caracterizan por sus bajas densidades ecológicas máximas, y por ocupar menor variedad de hábitats y tienen una distribución muy restringida a escala peninsular. Otra componente de la rareza regional se relaciona directamente con la talla corporal, de manera que las especies de mayor tamaño tienden a alcanzar menores densidades que las especies más pequeñas. Estos dos gradientes de rareza ecológica se asocian estrechamente con las actuales categorías oficiales de amenaza de las aves de Madrid, y permiten proponer y justificar posibles modificaciones al Catálogo regional para 11 especies (Cuchara Común – ‘De Interés Especial’; Calamón Común – ‘De Interés Especial’; Alcaraván Común – ‘Sensible a la Alteración de su Hábitat’; Paloma Zurita – ‘De Interés Especial’; Torcecuello Euroasiático – ‘Sensible a la Alteración de su Hábitat’; Calandria – descatalogarla; Mirlo Acuático - ‘Sensible a la Alteración de su Hábitat’; Colirrojo Real - ‘Sensible a la Alteración de su Hábitat’ o ‘Vulnerable’; Papamoscas Gris - ‘De Interés Especial’; Alcaudón Real Meridional – descatalogarla; Picogordo – ‘De Interés Especial’)., [EN] The conservation status of bird species of Comunidad de Madrid is analysed using the ecological breadth of the species, the distribution area, their habitat preferences, and maximum ecological densities in the region. The species which are less widely distributed in Madrid are characterized by their low maximum ecological densities, narrow habitat breadths, and limited distribution in the Iberian peninsular. Another component defining regional rarity shows that large-sized species tend to reach lower densities than small-sized birds. These two gradients of ecological rarity are closely associated with the current categories of threat status in Madrid, and allow the proposal and justification of possible modifications of the regional catalogue for 11 species.

Predictive habitat models rely on the relationship between a response variable (either occurrence or abundance of a species) and a set of environmental predictors. Vegetation is generally preferred as a source of potential predictors because of having a more direct link with reproductive necessities of species than topography and climate. However, vegetation maps are costly to produce and update and most land-use/land-cover maps are usually made with a general purpose, focused on land management, and not thinking on animal distribution. On the contrary, basic topographic and climatic maps are easier to obtain or to derive, are not so sensitive to legend design, and do not need of such frequent updates. In this study, we compare the predictive ability of different sets of environmental predictors when modelling the distribution of breeding birds. Models were generated for 79 bird species in South-western Spain using Generalised Additive Models (GAMs) with binomial errors and logit link. For each species, several models were created that differed in the set of candidate predictors initially tested (either derived from vegetation or from topo-climatic maps) or in the conditional order in which those predictor sets were tested. Within vegetation predictors, a similar strategy was used to ascertain the relative relevance of vegetation landscape (variables describing the surrounding habitat matrix) compared to vegetation cover (variables describing the type of vegetation found on sampling sites). Vegetation models were significantly more accurate than topo-climatic models, but the difference was due to the higher number of potential predictors in the set of vegetation variables. Vegetation landscape models were significantly more accurate than vegetation cover models, even when controlling for the number of candidate predictors. Models that included both sets of predictors (vegetation and topo-climatic variables) had a slightly superior predictive ability. Our results ind

Bird species are selective on the vegetation types in which they are found but predictive models of bird distribution based on variables derived from land-use/land-cover maps tend to have limited success. It has been suggested that accuracy of ex- isting maps used to derive predictors is in part responsible for the limited success of bird distribution models. In two areas of 4900 km2 of Western Andalusia, Spain, we compared the predictive ability of bird distribution models derived from two existing general-purpose land-use/land-cover maps, which differ in their resolution and accuracy: a coarse scale vegetation map of Europe, the CORINE land-cover map, and a detailed regional map, the 1995 land-use/land-cover map of Andalusia from the SINAMBA (Consejer´ıa de Medio Ambiente, Junta de Andaluc´ıa). We compared the bird distribution models derived from these general-purpose vegetation maps with models derived from two more accurate structural vegetation maps built considering directly variables that influence bird habitat selection, one built from satellite images for this study and another obtained by im- proving the resolution and accuracy of the SINAMBA map with satellite data. We sampled the presence/absence of bird species at 857 points using 15-min point surveys. Predictive models for 54 bird species were built with generalised additive models (GAMs), using as potential predictors the same set of landscape and vegetation structure variables measured on each map. We compared for each bird species the predictive accuracy of the best model derived from each map. Vegetation structure measured at bird sample points was used as ground-truth for comparing the accuracy of vegetation maps. Although maps differed in their resolution and accuracy, the results show that all of them produced similarly accurate bird distribution models, with a mixed map produced with both thematic and satellite information being the best. The models derived from the more accurate vegetation st

The main breeding populations of the red kite (Milvus milvus L.), have been declining in the Iberian peninsula during the last decade. However, there is a lack of regional assessments of habitat suitability that identifies limiting ecological factors for the species and areas with conservation problems. In this work we present a regional model for the distribution and abundance of breeding red kites in the Iberian peninsula. The occurrence and estimated abundance in 100 km2 UTM squares resulting from road censuses were modelled with broad-scale explanatory variables obtained from satellite imagery, thematic digital cartography, cli- matic data and spatial coordinates. The occurrence model incorporated mainly climatic variables and had a good discrimination ability, while the abundance model incorporated mainly land-use variables and had a lower explanatory power (r2=0.14). The predictions somewhat overestimated the results of the censuses, and this agrees with the decline of population size and range observed for this species in the Iberian peninsula. These models are relevant in the conservation of the species: first, they suggest the limiting factors for red kite in the Iberian peninsula, and, second, they generate predictive maps pointing out both areas in which conservation problems may be acute (suitable locations that are unoccupied), and areas where no data is available but the red kite is likely to be present (thus guiding further survey and research).

The ultrastructure of tomato leaf disks treated with a biostimulator (0.01 mg dm–3 BB6, brassinosteroid analogue from Cuba), and subjected to high temperature (40 °C for 1.5 h) was studied. High temperature stress caused the appearance of granules in the nucleus, nucleolus and cytoplasm. In chloroplasts and in mitochondria the internal membrane system was disorganised and in chloroplasts some starch granules were detected. These symptoms were more marked in the cells treated with BB6. The influence of BB6 on the ultrastructure of leaf cells was apparent also before being subjected to heat stress.