129 research outputs found

    Habitat fragmentation affects culture transmission: Patterns of song matching in Dupont's lark

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    1. Males of many bird species match song with neighbours during territorial interactions. Although bird vocal mimicry has received much attention, the relationships between song variation and ecological factors such as landscape geometry and habitat fragmentation are still poorly known, and most previous research has been limited to one or a few populations of a species. In this study we analysed the spatial patterns and ecological determinants of song matching in Dupont's lark Chersophilus duponti, a rare and specialized steppe passerine. 2. By recording bird songs from 21 Spanish and Moroccan localities, we analysed the effect of habitat fragmentation and the availability of suitable steppe habitat on the patterns of song matching in Dupont's lark, controlling for other potential determinants such as period in the breeding season, intensity of competition, geographical location and spatial distribution of individuals. 3. Both song-type sharing (match of song types in the repertoire) and spectrotemporal matching (convergence in the acoustic features of the same song type) were greater between counter-singing neighbours than between non-neighbours, and spatial autocorrelation (similarities between singing individuals) only occurred at short distances. The study localities differed in the amount of overall acoustic matching between individuals, seemingly as a consequence of local differences in the intensity of male competition and in the availability of suitable habitat. 4. The levels of song-type sharing between non-neighbours tended to increase and those among neighbours to decrease with the increase of steppeland availability. Moreover, the existing differences in sharing between neighbours and non-neighbours were significantly affected by the presence of elements of fragmentation in the steppe. In fragmented habitats, song sharing among neighbours was enhanced, possibly because of harsher competition for limited resources; conversely, sharing among non-neighbours dropped, probably because of the lack of interactions among individuals isolated by habitat barriers. 5. Synthesis and applications. Anthropogenic habitat barriers could alter bird perception of the spatial distribution of rivals over distance, leading to a contraction of the spatial range of the individual acoustic niche. We suggest that communication systems of habitat-sensitive species might be used as a behavioural indicator of anthropogenic environmental deterioration. Because of their rapidly evolving cultural nature, bird vocalizations might become an early warning system detecting the effects of fragmentation over relatively short times and before other indicators (such as genetic markers) show any change. © 2005 British Ecological Society.Peer Reviewe

    Plastic Responses to Temperature Versus Local Adaptation at the Cold Extreme of the Climate Gradient

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    Climate is a strong selection agent at high elevations, but experimental examinations of how animals exclusive of highlands cope with its variation are scarce. We analysed temperature-induced variation of early ontogenetic traits in the alpine grasshopper Chorthippus cazurroi, and compared populations from the elevational extremes of the species distribution under laboratory conditions spanning natural temperature ranges. Neither elevation of origin, nor different growing temperatures, had a direct effect on nymph body size, but both factors contributed to size at hatching indirectly, via their effect on the duration of embryo development. Large emerging nymphs had a consistently greater survival, although small and fast-developing nymphs from highlands also performed well at low temperatures. Viability selection favoured fast-developing phenotypes in conditions in which plasticity delayed development, in a typical countergradient pattern. Growth in the successive stage did not compensate for slow development at hatching, thus responses at this early stage have potential long-lasting consequences. Although phenotypic selection during early development certifies the strength of selection imposed by cold temperatures in the laboratory, elevation clines of body size did not emerge in either nymphs or the wild parental generation. Differentiation in the wild may be levelled out by fecundity selection for large sizes, drift and gene flow resulting from the fragmentation and proximity of populations, or by micro-climatic differences that reduce the likelihood of directional selection. There is therefore potential for local adaptation to temperature, but a series of conditions typical of alpine environments and ectotherms may impair, confound or constrain full differentiation along the gradient.We are grateful to M. Martini and A. Segura for their help during grasshopper rearing and to J. Moya for borrowing us HOBO sensors. We also thank Picos de Europa National Park for the permissions to capture adult grasshoppers in the study area, S. Young for editing the English, and two anonymous referees for providing useful comments on a former version of the manuscript. Funding for this study was provided by the British Ecological Society (Grant N. 4278/5250) and the Spanish Ministry of Economy and Competitiveness (CGL2011-28177, CGL2014-53899-P).Peer reviewe

    Local climate determines intra- and interspecific variation in sexual size dimorphism in mountain grasshopper communities

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    The climate is often evoked to explain broad-scale clines of body size, yet its involvement in the processes that generate size inequality in the two sexes (sexual size dimorphism) remains elusive. Here, we analyse climatic clines of sexual size dimorphism along a wide elevation gradient (i) among grasshopper species in a phylogenetically controlled scenario and (ii) within species differing in distribution and cold tolerance, to highlight patterns generated at different time scales, mainly evolutionary (among species or higher taxa) and ontogenetic or microevolutionary (within species). At the interspecific level, grasshoppers were slightly smaller and less dimorphic at high elevations. These clines were associated with gradients of precipitation and sun exposure, which are likely indicators of other factors that directly exert selective pressures, such as resource availability and conditions for effective thermoregulation. Within species, we found a positive effect of temperature and a negative effect of elevation on body size, especially on condition-dependent measures of body size (total body length rather than hind femur length) and in species inhabiting the highest elevations. In spite of a certain degree of species-specific variation, females tended to adjust their body size more often than males, suggesting that body size in females can evolve faster among species and can be more plastic or dependent on nutritional conditions within species living in adverse climates. Natural selection on female body size may therefore prevail over sexual selection on male body size in alpine environments, and abiotic factors may trigger consistent phenotypic patterns across taxonomic scales.Funding was partially provided by the Spanish Ministries of Science and Innovation (grants CGL2008-02749, CGL2009-11302 and CGL2011-28177) and Agriculture and Environment (grant 375/2011). J.C. Illera was supported by a Ramón y Cajal postdoctoral fellowship.Peer reviewe

    Planning & Open-Air Demonstrating Smart City Sustainable Districts

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    The article is focused on the \u201cdemonstration\u201d activities carried out by the University of Genoa at Savona Campus facilities in order to implement the \u201cLiving Lab Smart City\u201d. The idea is to transform the Savona Campus in a Living Lab of the City of the Future: smart technologies in Information and Communication Technology (ICT) and energy sectors were installed in order to show a real application of the Smart City concept to population and external stakeholders. Moreover, special attention was given to the environment, personal wellbeing, and social equalities. The sustainable energy Research Infrastructures (RIs) of Savona Campus allowed enhancement of the applied research in degree programs and the collaboration with several companies. In particular, an important partnership with the Italian electric Distribution System Operator (DSO), ENEL S.p.A., started in 2017 to test the capability of these RIs to operate disconnected from the National Grid, relying only on the supply of renewables and storage systems. The \u201cLiving Lab Smart City\u201d is an important action to reduce the carbon footprint of the Savona Campus and to increase the awareness of students, teachers and researchers towards Sustainable Development in Higher Education Institutes

    The Smart City Energy Infrastructures at the Savona Campus of the University of Genoa

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    This paper presents ongoing research activities and technology upgrades carried out by the Power System Research team of the University of Genoa on the Smart City test-bed facilities installed at the Savona Campus. These facilities consist of a Smart Polygeneration Microgrid (SPM) feeding the Campus, of a Smart Energy Building (SEB) connected to the SPM and acting as a \u201cprosumer\u201d and of an Energy Management System (EMS) controlling the Campus generating units and thermal and electrical loads. The SPM, initially set up as a grid-tied system, is now subjected to further improvements in order to be operated in islanded mode. The paper shows that all the aforementioned infrastructures constitute a real example of how to build a sustainable smart city

    The intensity of male-male interactions declines in highland songbird populations

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s00265-015-1961-6Elevation 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 itThe research was supported by the Ministry of Economy and Competitiveness (project CGL2011-2817 to PL, FPI grant BES-2012-053472 to G

    HABITAT SELECTION OF HOODED AND CARRION CROWS IN THE ALPINE HYBRID ZONE

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    ABSTRACT Habitat selection of, co-existing Hooded Crows Corvus carone cornix and Carrion Crows C. c. carone was studied in the Susa valley, an alpine valley in the Italian hybrid zone. Foraging habitat use by the two races was not significantly different during the autumn-winter whereas it was during the spring-summer when Hooded Crows preferred meadows and Carrion Crows preferred dunged fields and maize stubble. However, if similar habitat categories (e.g. meadows and dunged meadows, maize and maize stubble) were combined, differences were no longer statistically significant. Resource selection by the two crows was more differentiated when only homotypic groups were taken into account suggesting that mixed flocking serves to standardize ecological choices. Analysis of flocking behaviour showed a clear tendency to avoid heterotypic flocks. The results of habitat selection are not in keeping with those reported by Saino (1992) in another plain area of north-western Italy, where there was a clear differentiation in the use of habitat categories during the winter. These differences, together with those regarding assortative mating, suggest that the alpine hybridization zone might be a mosaic of populations differentiated in relation to the locally diverse ecological conditions

    Song Diversity Predicts the Viability of Fragmented Bird Populations

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    In the global scenario of increasing habitat fragmentation, finding appropriate indicators of population viability is a priority for conservation. We explored the potential of learned behaviours, specifically acoustic signals, to predict the persistence over time of fragmented bird populations. We found an association between male song diversity and the annual rate of population change, population productivity and population size, resulting in birds singing poor repertoires in populations more prone to extinction. This is the first demonstration that population viability can be predicted by a cultural trait (acquired via social learning). Our results emphasise that cultural attributes can reflect not only individual-level characteristics, but also the emergent population-level properties. This opens the way to the study of animal cultural diversity in the increasingly common human-altered landscapes

    A simple strategy to optimally design and manage a photovoltaic plant integrated with a storage system for different applications

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    The main goal of the present paper is that of proposing a methodology for the optimal sizing of a Photovoltaic (PV) unit and a Storage (ST) device, basing on data concerning typical load and PV production profiles. To achieve this result, a set of simple requirements to manage the charging/discharging of the storage is firstly proposed. Then, the overall cost of the whole system is deduced as a function of two variables (PV and ST sizes) and minimized in order to find the optimal sizing of the system. Finally, an economic analysis is presented to determine whether or not the investment is profitable

    Divergent responses of flagship, keystone and resource-limited bio-indicators to forest structure

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    Bio-indicators are often proposed to set conservation priorities in forest habitat owing to the difficulties of determining forest intrinsic ecological value. Here, we tested the efficacy of a number of potential bird indicator groups in monitoring beech Fagus sylvatica forest status by analyzing their associations with the spatial and structural variables of forest vegetation that indicate key ecological patterns and processes. The density of cavity nesting birds, indicating the presence of limited forest resources (resource-limited indicators), was influenced by tree species diversity, vertical species mingling and diameter, parameters reflecting maturity, gap-dynamic processes, as well as resource and shelter availability. Heterogeneity in shrub species composition, another parameter depending on forest dynamics, was positively associated with the occurrence of Capercaillie, a “flagship” species for forest conservation. The presence of woodpeckers, a “keystone” group that provides shelter and foraging substrate to other organisms, was positively affected by the basal area of standing dead trees that is indirectly associated with natural nutrient availability. These findings suggest that single indicators fail to provide a complete assessment of forest status, and their use in monitoring or managing forest ecosystem need to be contextualized to specific ecological patterns. The combined use of several indicators, representing various taxa, functions and life histories, appears to be preferable, and is logistically feasible if these can be surveyed together. Several indicators would likely display a wider range of sensitivities to the modification of natural processes and permit more comprehensive tracking of forest dynamics than single flagship, keystone or resource-limited indicators.The study was funded by the Environmental Agency of Asturias (Grant CN-07-174 to J.R.O.) and by the Spanish Ministry of Science and Innovation (Grants CGL2008-02749 and CGL2009-11302 to P.L and J.R.O). J.C.S. was funded by a FICYT “Severo Ochoa” fellowship.Peer reviewe
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