Populations at the far edges of their ranges tend to be scarce, and they are frequently of conser... more Populations at the far edges of their ranges tend to be scarce, and they are frequently of conservation concern. This paper examines the distribution of three raptors (Circaetus gallicus, Hieraaetus pennatus and Milvus migrans) at the southwestern boundary of their breeding range. We modelled species distribution to obtain habitat suitability indexes that were validated with extensive fieldwork in Morocco and Spain. Our results support a strong effect of habitat suitability and a bottleneck effect of the Strait of Gibraltar on raptor distribution. However, after controlling for these effects, the three species were scarcer in Morocco than in Spain. We did not find differences between the two countries in the number of power lines that are dangerous to raptors or in general impacts of agricultural intensification on bird populations (we assessed more farmland birds in Morocco). However, many more people (i.e., shepherds) were detected in Morocco, whose negative effect on raptors could explain the depletion of their populations. These transboundary differences are used to discuss the fate of these peripheral populations in a context of climate change and rural abandonment. They also highlight the need for strengthening raptor conservation around the Strait of Gibraltar, where a permanent flow of raptors converges throughout the year.
Knowledge of the ability of birds to track spatiotemporal variation in fruit distribution is esse... more Knowledge of the ability of birds to track spatiotemporal variation in fruit distribution is essential for understanding plant-frugivore interactions. Arguably, although total fruit availability sets an upper limit to the number of birds that can exploit a habitat patch, not all species can equally distribute abundance according to variation in fruit resources. To explore this, we studied bird and fruit abundance in 1999Á2005 in Mediterranean scrublands and woodlands of southern Spain. We analysed whether changes of fruit abundance in eight different sites during six winters could predict numerical changes of a set of frugivorous passerines of the area (blackcap Sylvia atricapilla, Sardinian warbler S. melanocephala, robin Erithacus rubecula, song thrush Turdus philomelos and blackbird T. merula). We also investigated if all frugivores together tracked fruits better than individual species, thereby supporting a shared use of resources. Results showed strong interspecific differences. Only the most abundant species (blackcaps and robins) tracked the spatial patterning of food despite strong differences in the use of space (vagrant and territorial, respectively). This suggests plastic behaviour of territorial robins, with individuals changing from strictly territorial to wandering, a flexibility that would favour between-site numerical arrangements according to food resources. Annual changes in bird numbers were independent of the availability of fruits, except for blackcaps, an abundant vagrant bird that tracked inter-winter changes in fruit abundance. The abundance of blackcaps fitted the spatiotemporal patterning of fruit resources better than the whole guild of frugivorous birds, inconsistent with the idea that these species track together the changing availability of fruit resources.
The European turtle dove (Streptopelia turtur) is classified as vulnerable by the IUCN. In this c... more The European turtle dove (Streptopelia turtur) is classified as vulnerable by the IUCN. In this context, it is important to explore the factors affecting its abundance and the ways in which it can be effectively managed for conservation. This study compares the distribution of this dove in Spain and Morocco. These countries, which are separated by the Strait of Gibraltar, are each occupied by a different subspecies (i.e. Streptopelia turtur turtur in Spain and S. t. arenicola in Morocco) that may be adapted to different environmental conditions. Such differentiation could result in differences in the species’ abundance between the two countries. The occurrence of this dove was assessed by means of road counts, and the resulting records were used to explore the niche overlap between the two subspecies. The niches of both populations overlapped, suggesting the selection of similar environmental conditions in the two countries. However, the species occurred more frequently in Morocco than in Spain. To study the potential role of local effects on the observed differences in abundance, 494 sampling points were surveyed in four different sectors of Spain and Morocco. These additional counts indicated that, after controlling for the effect of local habitat structure and climate, the European turtle dove is more frequent in Morocco than in Spain. Differences between the two countries, in relation to hunting pressure, agricultural intensification and the abandonment of marginal cultures and woodlands, could account for the observed transboundary differences in the abundance of European turtle dove and help to explain its severe decline in Spain.
BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.
Social networks, computational intelligence and electoral prediction: the case of the presidentia... more Social networks, computational intelligence and electoral prediction: the case of the presidential primaries of Chile 2017 Redes sociais, inteligência computacional e previsão eleitoral: o caso das primárias presidenciais do Chile 2017
Resumen: El aceite de ricino se modificó por transesterificación con pentaeritritol. Paralelament... more Resumen: El aceite de ricino se modificó por transesterificación con pentaeritritol. Paralelamente, se utilizó la reacción de glucosilación con glicerol para dividir el almidón en unidades monosacáridos. El glucósido obtenido reaccionó por transesterificación con el aceite modificado por transesterificación con pentaeritritol. Se determinó el índice de hidroxilo de los poliol-glucósidos en función del contenido de pentaeritritol y almidón utilizados en la síntesis. Se sintetizaron redes interpenetradas de polímero de manera simultánea (SINs) con diferentes relaciones en peso poliuretano/PMMA de 100/0, 90/10, 80/20, 70/30, 60/40 y 50/50. Para la síntesis de la red de poliuretano (PU) se utilizaron los poliol-glucósidos y diisocianato de isoforona (IPDI) o con una relación NCO/OH = 1 y para la síntesis de la red de polimetilmetacrilato (PMMA) se utilizó peróxido de benzoílo como agente iniciador y dimetacrilato de etilenglicol como agente entrecruzante. Los SINs se caracterizaron por sus propiedades fisicomecánicas como resistencia al ataque químico, dureza, resistencia a la tensión y elongación de ruptura. La estabilidad térmica de los SINs se determinó usando análisis termogravimétrico (TGA). La morfología de superficie se determinó usando microscopia electrónica de barrido (SEM) y mostró una morfología de dos fases para todos los SINs.
Chemical modification of cassava starch was conducted through an acylation reaction by using pyri... more Chemical modification of cassava starch was conducted through an acylation reaction by using pyridine and propionic anhydride to replace the functional groups of starch. Polyurethane elastomers were prepared using suspensions of the mixture obtained from castor oil and yucca starch that was modified by a propionic anhydride reaction. The suspensions were characterized by means of tests based on The Fourier Transform Infrared Spectroscopy and the Hydroxyl Index. The castor oil-AMP suspensions were used for the PU synthesis. The PUs were characterized by their physical-mechanical properties like tension-deformation and Shore A. hardness, thermal gravimetric analysis and swelling test. The density cross-linking of from swelling tests was determined by applying the Flory-Rehner equation.
There are always risks associated with silos when the stored material has been characterized as p... more There are always risks associated with silos when the stored material has been characterized as prone to self-ignition or explosion. Further research focused on the characterization of agricultural materials stored in silos is needed due to the lack of data found in the literature. The aim of this study was to determine the ignitability and explosive parameters of several agricultural products commonly stored in silos in order to assess the risk of ignition and dust explosion. Minimum Ignition Temperature, with dust forming a cloud and deposited in a layer, Lower Explosive Limit, Minimum Ignition Energy, Maximum Explosion Pressure and Maximum Explosion Pressure Rise were determined for seven agricultural materials: icing sugar, maize, wheat and barley grain dust, alfalfa, bread-making wheat and soybean dust. Following characterization, these were found to be prone to producing self-ignition when stored in silos under certain conditions.
The functional relationship between habitat and populations provides the conceptual background fo... more The functional relationship between habitat and populations provides the conceptual background for current methodolog-ical approaches to bird conservation (Ausden, 2004; Morrison et al.
El efecto península es un patrón según el cual la riqueza de especies disminuye en función de la ... more El efecto península es un patrón según el cual la riqueza de especies disminuye en función de la distancia al continente. Sin embargo, este patrón es frecuentemente enmascarado por la incidencia de variables ambientales. En este trabajo estudiamos el efecto relativo de la ubicación geográfica y de un conjunto de variables ambientales (temperatura, precipitación, cobertura forestal…) sobre la distribución de la riqueza de especies de aves forestales en España peninsular. Los resultados sugieren que tanto la posición geográfica como las condiciones ambientales afectan a la distribución de la riqueza de aves. También se estudia si estos resultados varían en función de las características particulares de las áreas estudiadas. Para esta segunda aproximación se definieron dos corredores de similar longitud ubicados entre las costas atlánticas y mediterráneas y las montañas interiores. El corredor Atlántico mostró una elevada homogeneidad ambiental en toda su extensión, mientras el corredor Mediterráneo presentó un marcado gradiente desde las áreas más húmedas del norte a las condiciones más secas del sur. Los resultados muestran que en el corredor Atlántico la distancia al continente, no las condiciones ambientales, fue la principal predictora de la riqueza de especies, mientras que en el corredor Mediterráneo las variables ambientales fueron mejores predictoras de la distribución de la riqueza. Estos resultados son utilizados para discutir algunos aspectos biogeográficos y metodológicos de la distribución de aves forestales en la Península Ibérica.
Aim The study of parasite biogeography on islands is important for our understanding of both the ... more Aim The study of parasite biogeography on islands is important for our understanding of both the processes involved in the evolution of parasite assemblages worldwide and the ecology and conservation of insular communities. By studying the haemosporidian blood parasites of a bird that has recently colonized a number of oceanic islands, we were able to test hypotheses relating to the processes of parasite colonization and community assembly prior to the permanent isolation of host species on islands. Location The Atlantic Ocean archipelagos of Madeira and the Canary Islands. Methods We used cytochrome b DNA sequences to determine the prevalence and richness of parasites of the genera Haemoproteus, Plasmodium and Leucocytozoon in blackcaps, Sylvia atricapilla, a widespread passerine that colonized these archipelagos during the Last Glacial Maximum. We compared insular blackcap parasite assemblages with those observed in 37 blackcap populations sampled on mainland Europe. Results The insular parasite assemblage was impoverished, containing c. 10% of the parasites found on the continent. None of the parasites observed on the islands were blackcap specific. Some of the observed parasites appear to have switched from blackcaps to other Macaronesian host species, whereas others were of Afrotropical origin and were acquired after blackcaps colonized the islands. The prevalence of parasites in the island populations of blackcaps was lower than in mainland blackcap populations and parasite richness decreased with increasing island distance to the continent. Main conclusions Macaronesian blackcaps do not face the strong parasite load encountered by their mainland counterparts despite the fact that blackcap migration from the continent may directly transport mainland blackcap parasites to the islands. This supports the idea that normal mainland host-parasite associations are compromised on islands and that parasite island syndromes (low richness, frequent host-switching and reduced specialization) evolve even before insular host populations become completely isolated from their mainland counterparts.
Capsule Iberian Chiffchaffs Phylloscopus (collybita) brehmii are genetically, morphologically and... more Capsule Iberian Chiffchaffs Phylloscopus (collybita) brehmii are genetically, morphologically and bioacoustically different from European Chiffchaffs (P. [c.] collybita). Aim To examine the difference in migratory pattern between brehmii and collybita. Methods We inferred variation in distance of migration between brehmii and collybita by analysing differences in flight-related morphology (wing-length, wing shape and tail-length) between individuals breeding or wintering in the Iberian Peninsula. Results Controlling for body size and allometry of feather dimensions, birds captured in spring had more pointed wings (more concave wing shapes and pointed wing tips) and a shorter tail than birds caught in winter, although no spring-to-winter difference was found for wing-length. Conclusion Iberian breeders appear better suited to long-distance migration (their traits are likely to give a higher speed and a lower energy consumption during long non-stop flights) than wintering individuals, which strongly supports the hypothesis that brehmii move south of the Sahara in autumn and are substituted by central European collybita populations in winter. This different migration pattern of brehmii and collybita has important implications for the maintenance of differentiation in their contact zone, because selection against hybrids with maladaptive, intermediate migratory behaviours might contribute to reproductive isolation.
SummaryMigratory birds are critically dependent on adequate wintering habitats for their long-ter... more SummaryMigratory birds are critically dependent on adequate wintering habitats for their long-term survival. Cantabrian farmland, a mixed agricultural landscape extending across the coastal lowlands of northern Spain, constitutes an important wintering area for many short-distance migrants coming from central-western and northern Europe. Unfortunately, the Common Agricultural Policy of the European Union and national afforestation schemes have resulted in a massive replacement of farmland by pinePinusspp. and eucalyptEucalyptussp. plantations. This work assesses the importance of Cantabrian farmland as wintering grounds for short-distance European migrants and for wintering species that originate in nearby woodlands. We examined the seasonal changes in passerine bird populations in the Cantabrian region and used winter ringing recoveries obtained in the area to evaluate the contribution made by European migrants to winter populations. Bird communities were surveyed along 299 500-m l...
Migratory frugivorous birds disperse the seeds of many plant species, forming mutualistic associa... more Migratory frugivorous birds disperse the seeds of many plant species, forming mutualistic associations that render frugivores a priority for conservation in many habitats worldwide. We analysed the distribution of seed-dispersing frugivorous passerines in southern Spain, which is an important area for the conservation of European birds during winter. Frugivorous birds showed similar regional abundance and richness during four winters, although fruit availability changed among years. However, the spatial distribution of frugivorous birds in the area changed among years. These changes were principally determined by annual variation in the distribution of fruits in the area, revealing a clear ability of birds to track the distribution of fruits. The unpredictable distribution of fruits each year suggests that regional fruit crops, rather than selected habitat patches, need to be protected for the long-term conservation of frugivorous bird populations in wintering grounds. Remarkably, the distribution of frugivores was independent of forest development or general cover of shrubs, which helps to reconcile the protection of fruiting shrubs with forest cleaning, an usual management to prevent devastating summer fires that is destroying fleshy-fruited plant communities in many areas of southern Spain. Thus, leaving a part of the fruiting shrubs untouched when cleaning forest undergrowth will allow the settlement of frugivorous birds. Interestingly, both abundance and richness of frugivores decreased with elevation, probably as a consequence of impaired climatic conditions at high altitude, revealing the importance of lowland shrublands as wintering grounds for frugivorous birds. These habitats deserve special conservation efforts, as they are seriously threatened by the ongoing encroachment of agricultural and urban areas along the Mediterranean coasts.
Información del artículo Conservation opportunities in spanish juniper "juniperus thurif... more Información del artículo Conservation opportunities in spanish juniper "juniperus thurifera" woodlands: the case of migratory thrusher "turdus" spp.
Populations at the far edges of their ranges tend to be scarce, and they are frequently of conser... more Populations at the far edges of their ranges tend to be scarce, and they are frequently of conservation concern. This paper examines the distribution of three raptors (Circaetus gallicus, Hieraaetus pennatus and Milvus migrans) at the southwestern boundary of their breeding range. We modelled species distribution to obtain habitat suitability indexes that were validated with extensive fieldwork in Morocco and Spain. Our results support a strong effect of habitat suitability and a bottleneck effect of the Strait of Gibraltar on raptor distribution. However, after controlling for these effects, the three species were scarcer in Morocco than in Spain. We did not find differences between the two countries in the number of power lines that are dangerous to raptors or in general impacts of agricultural intensification on bird populations (we assessed more farmland birds in Morocco). However, many more people (i.e., shepherds) were detected in Morocco, whose negative effect on raptors could explain the depletion of their populations. These transboundary differences are used to discuss the fate of these peripheral populations in a context of climate change and rural abandonment. They also highlight the need for strengthening raptor conservation around the Strait of Gibraltar, where a permanent flow of raptors converges throughout the year.
Knowledge of the ability of birds to track spatiotemporal variation in fruit distribution is esse... more Knowledge of the ability of birds to track spatiotemporal variation in fruit distribution is essential for understanding plant-frugivore interactions. Arguably, although total fruit availability sets an upper limit to the number of birds that can exploit a habitat patch, not all species can equally distribute abundance according to variation in fruit resources. To explore this, we studied bird and fruit abundance in 1999Á2005 in Mediterranean scrublands and woodlands of southern Spain. We analysed whether changes of fruit abundance in eight different sites during six winters could predict numerical changes of a set of frugivorous passerines of the area (blackcap Sylvia atricapilla, Sardinian warbler S. melanocephala, robin Erithacus rubecula, song thrush Turdus philomelos and blackbird T. merula). We also investigated if all frugivores together tracked fruits better than individual species, thereby supporting a shared use of resources. Results showed strong interspecific differences. Only the most abundant species (blackcaps and robins) tracked the spatial patterning of food despite strong differences in the use of space (vagrant and territorial, respectively). This suggests plastic behaviour of territorial robins, with individuals changing from strictly territorial to wandering, a flexibility that would favour between-site numerical arrangements according to food resources. Annual changes in bird numbers were independent of the availability of fruits, except for blackcaps, an abundant vagrant bird that tracked inter-winter changes in fruit abundance. The abundance of blackcaps fitted the spatiotemporal patterning of fruit resources better than the whole guild of frugivorous birds, inconsistent with the idea that these species track together the changing availability of fruit resources.
The European turtle dove (Streptopelia turtur) is classified as vulnerable by the IUCN. In this c... more The European turtle dove (Streptopelia turtur) is classified as vulnerable by the IUCN. In this context, it is important to explore the factors affecting its abundance and the ways in which it can be effectively managed for conservation. This study compares the distribution of this dove in Spain and Morocco. These countries, which are separated by the Strait of Gibraltar, are each occupied by a different subspecies (i.e. Streptopelia turtur turtur in Spain and S. t. arenicola in Morocco) that may be adapted to different environmental conditions. Such differentiation could result in differences in the species’ abundance between the two countries. The occurrence of this dove was assessed by means of road counts, and the resulting records were used to explore the niche overlap between the two subspecies. The niches of both populations overlapped, suggesting the selection of similar environmental conditions in the two countries. However, the species occurred more frequently in Morocco than in Spain. To study the potential role of local effects on the observed differences in abundance, 494 sampling points were surveyed in four different sectors of Spain and Morocco. These additional counts indicated that, after controlling for the effect of local habitat structure and climate, the European turtle dove is more frequent in Morocco than in Spain. Differences between the two countries, in relation to hunting pressure, agricultural intensification and the abandonment of marginal cultures and woodlands, could account for the observed transboundary differences in the abundance of European turtle dove and help to explain its severe decline in Spain.
BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.
Social networks, computational intelligence and electoral prediction: the case of the presidentia... more Social networks, computational intelligence and electoral prediction: the case of the presidential primaries of Chile 2017 Redes sociais, inteligência computacional e previsão eleitoral: o caso das primárias presidenciais do Chile 2017
Resumen: El aceite de ricino se modificó por transesterificación con pentaeritritol. Paralelament... more Resumen: El aceite de ricino se modificó por transesterificación con pentaeritritol. Paralelamente, se utilizó la reacción de glucosilación con glicerol para dividir el almidón en unidades monosacáridos. El glucósido obtenido reaccionó por transesterificación con el aceite modificado por transesterificación con pentaeritritol. Se determinó el índice de hidroxilo de los poliol-glucósidos en función del contenido de pentaeritritol y almidón utilizados en la síntesis. Se sintetizaron redes interpenetradas de polímero de manera simultánea (SINs) con diferentes relaciones en peso poliuretano/PMMA de 100/0, 90/10, 80/20, 70/30, 60/40 y 50/50. Para la síntesis de la red de poliuretano (PU) se utilizaron los poliol-glucósidos y diisocianato de isoforona (IPDI) o con una relación NCO/OH = 1 y para la síntesis de la red de polimetilmetacrilato (PMMA) se utilizó peróxido de benzoílo como agente iniciador y dimetacrilato de etilenglicol como agente entrecruzante. Los SINs se caracterizaron por sus propiedades fisicomecánicas como resistencia al ataque químico, dureza, resistencia a la tensión y elongación de ruptura. La estabilidad térmica de los SINs se determinó usando análisis termogravimétrico (TGA). La morfología de superficie se determinó usando microscopia electrónica de barrido (SEM) y mostró una morfología de dos fases para todos los SINs.
Chemical modification of cassava starch was conducted through an acylation reaction by using pyri... more Chemical modification of cassava starch was conducted through an acylation reaction by using pyridine and propionic anhydride to replace the functional groups of starch. Polyurethane elastomers were prepared using suspensions of the mixture obtained from castor oil and yucca starch that was modified by a propionic anhydride reaction. The suspensions were characterized by means of tests based on The Fourier Transform Infrared Spectroscopy and the Hydroxyl Index. The castor oil-AMP suspensions were used for the PU synthesis. The PUs were characterized by their physical-mechanical properties like tension-deformation and Shore A. hardness, thermal gravimetric analysis and swelling test. The density cross-linking of from swelling tests was determined by applying the Flory-Rehner equation.
There are always risks associated with silos when the stored material has been characterized as p... more There are always risks associated with silos when the stored material has been characterized as prone to self-ignition or explosion. Further research focused on the characterization of agricultural materials stored in silos is needed due to the lack of data found in the literature. The aim of this study was to determine the ignitability and explosive parameters of several agricultural products commonly stored in silos in order to assess the risk of ignition and dust explosion. Minimum Ignition Temperature, with dust forming a cloud and deposited in a layer, Lower Explosive Limit, Minimum Ignition Energy, Maximum Explosion Pressure and Maximum Explosion Pressure Rise were determined for seven agricultural materials: icing sugar, maize, wheat and barley grain dust, alfalfa, bread-making wheat and soybean dust. Following characterization, these were found to be prone to producing self-ignition when stored in silos under certain conditions.
The functional relationship between habitat and populations provides the conceptual background fo... more The functional relationship between habitat and populations provides the conceptual background for current methodolog-ical approaches to bird conservation (Ausden, 2004; Morrison et al.
El efecto península es un patrón según el cual la riqueza de especies disminuye en función de la ... more El efecto península es un patrón según el cual la riqueza de especies disminuye en función de la distancia al continente. Sin embargo, este patrón es frecuentemente enmascarado por la incidencia de variables ambientales. En este trabajo estudiamos el efecto relativo de la ubicación geográfica y de un conjunto de variables ambientales (temperatura, precipitación, cobertura forestal…) sobre la distribución de la riqueza de especies de aves forestales en España peninsular. Los resultados sugieren que tanto la posición geográfica como las condiciones ambientales afectan a la distribución de la riqueza de aves. También se estudia si estos resultados varían en función de las características particulares de las áreas estudiadas. Para esta segunda aproximación se definieron dos corredores de similar longitud ubicados entre las costas atlánticas y mediterráneas y las montañas interiores. El corredor Atlántico mostró una elevada homogeneidad ambiental en toda su extensión, mientras el corredor Mediterráneo presentó un marcado gradiente desde las áreas más húmedas del norte a las condiciones más secas del sur. Los resultados muestran que en el corredor Atlántico la distancia al continente, no las condiciones ambientales, fue la principal predictora de la riqueza de especies, mientras que en el corredor Mediterráneo las variables ambientales fueron mejores predictoras de la distribución de la riqueza. Estos resultados son utilizados para discutir algunos aspectos biogeográficos y metodológicos de la distribución de aves forestales en la Península Ibérica.
Aim The study of parasite biogeography on islands is important for our understanding of both the ... more Aim The study of parasite biogeography on islands is important for our understanding of both the processes involved in the evolution of parasite assemblages worldwide and the ecology and conservation of insular communities. By studying the haemosporidian blood parasites of a bird that has recently colonized a number of oceanic islands, we were able to test hypotheses relating to the processes of parasite colonization and community assembly prior to the permanent isolation of host species on islands. Location The Atlantic Ocean archipelagos of Madeira and the Canary Islands. Methods We used cytochrome b DNA sequences to determine the prevalence and richness of parasites of the genera Haemoproteus, Plasmodium and Leucocytozoon in blackcaps, Sylvia atricapilla, a widespread passerine that colonized these archipelagos during the Last Glacial Maximum. We compared insular blackcap parasite assemblages with those observed in 37 blackcap populations sampled on mainland Europe. Results The insular parasite assemblage was impoverished, containing c. 10% of the parasites found on the continent. None of the parasites observed on the islands were blackcap specific. Some of the observed parasites appear to have switched from blackcaps to other Macaronesian host species, whereas others were of Afrotropical origin and were acquired after blackcaps colonized the islands. The prevalence of parasites in the island populations of blackcaps was lower than in mainland blackcap populations and parasite richness decreased with increasing island distance to the continent. Main conclusions Macaronesian blackcaps do not face the strong parasite load encountered by their mainland counterparts despite the fact that blackcap migration from the continent may directly transport mainland blackcap parasites to the islands. This supports the idea that normal mainland host-parasite associations are compromised on islands and that parasite island syndromes (low richness, frequent host-switching and reduced specialization) evolve even before insular host populations become completely isolated from their mainland counterparts.
Capsule Iberian Chiffchaffs Phylloscopus (collybita) brehmii are genetically, morphologically and... more Capsule Iberian Chiffchaffs Phylloscopus (collybita) brehmii are genetically, morphologically and bioacoustically different from European Chiffchaffs (P. [c.] collybita). Aim To examine the difference in migratory pattern between brehmii and collybita. Methods We inferred variation in distance of migration between brehmii and collybita by analysing differences in flight-related morphology (wing-length, wing shape and tail-length) between individuals breeding or wintering in the Iberian Peninsula. Results Controlling for body size and allometry of feather dimensions, birds captured in spring had more pointed wings (more concave wing shapes and pointed wing tips) and a shorter tail than birds caught in winter, although no spring-to-winter difference was found for wing-length. Conclusion Iberian breeders appear better suited to long-distance migration (their traits are likely to give a higher speed and a lower energy consumption during long non-stop flights) than wintering individuals, which strongly supports the hypothesis that brehmii move south of the Sahara in autumn and are substituted by central European collybita populations in winter. This different migration pattern of brehmii and collybita has important implications for the maintenance of differentiation in their contact zone, because selection against hybrids with maladaptive, intermediate migratory behaviours might contribute to reproductive isolation.
SummaryMigratory birds are critically dependent on adequate wintering habitats for their long-ter... more SummaryMigratory birds are critically dependent on adequate wintering habitats for their long-term survival. Cantabrian farmland, a mixed agricultural landscape extending across the coastal lowlands of northern Spain, constitutes an important wintering area for many short-distance migrants coming from central-western and northern Europe. Unfortunately, the Common Agricultural Policy of the European Union and national afforestation schemes have resulted in a massive replacement of farmland by pinePinusspp. and eucalyptEucalyptussp. plantations. This work assesses the importance of Cantabrian farmland as wintering grounds for short-distance European migrants and for wintering species that originate in nearby woodlands. We examined the seasonal changes in passerine bird populations in the Cantabrian region and used winter ringing recoveries obtained in the area to evaluate the contribution made by European migrants to winter populations. Bird communities were surveyed along 299 500-m l...
Migratory frugivorous birds disperse the seeds of many plant species, forming mutualistic associa... more Migratory frugivorous birds disperse the seeds of many plant species, forming mutualistic associations that render frugivores a priority for conservation in many habitats worldwide. We analysed the distribution of seed-dispersing frugivorous passerines in southern Spain, which is an important area for the conservation of European birds during winter. Frugivorous birds showed similar regional abundance and richness during four winters, although fruit availability changed among years. However, the spatial distribution of frugivorous birds in the area changed among years. These changes were principally determined by annual variation in the distribution of fruits in the area, revealing a clear ability of birds to track the distribution of fruits. The unpredictable distribution of fruits each year suggests that regional fruit crops, rather than selected habitat patches, need to be protected for the long-term conservation of frugivorous bird populations in wintering grounds. Remarkably, the distribution of frugivores was independent of forest development or general cover of shrubs, which helps to reconcile the protection of fruiting shrubs with forest cleaning, an usual management to prevent devastating summer fires that is destroying fleshy-fruited plant communities in many areas of southern Spain. Thus, leaving a part of the fruiting shrubs untouched when cleaning forest undergrowth will allow the settlement of frugivorous birds. Interestingly, both abundance and richness of frugivores decreased with elevation, probably as a consequence of impaired climatic conditions at high altitude, revealing the importance of lowland shrublands as wintering grounds for frugivorous birds. These habitats deserve special conservation efforts, as they are seriously threatened by the ongoing encroachment of agricultural and urban areas along the Mediterranean coasts.
Información del artículo Conservation opportunities in spanish juniper "juniperus thurif... more Información del artículo Conservation opportunities in spanish juniper "juniperus thurifera" woodlands: the case of migratory thrusher "turdus" spp.
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