Efecto del medioambiente sobre la biología reproductiva de dos especies de aves insectívoras forestales en los Montes de Toledo

Peer reviewe

Habitat fragmentation influences nestling growth in Mediterranean blue and great tits

In patchy forest areas, the size of the forest patch where birds breed has a strong influence on their breeding success. However, the proximate effects contributing to lowering the breeding success in small forest patches remain unclear; and a shortage of crucial resources in those forest patches has been suggested to account in some degree for this failure. With the aim to further investigate this issue, we have monitored the breeding cycle of blue and great tits in three ‘large’ forest patches (ranging between 26.5-29.6 ha) and twelve ‘small’ forest patches (ranging between 1.1-2.1 ha) in a Mediterranean area in central Spain, during three years (2011-2013). We also recorded the nestling diet inside the nest-boxes with the aid of handy-cams. Only males significantly differed between forest patch size categories; being on average younger and with better body condition in small patches for great and blue tits respectively. Reproductive traits did not vary between forest patch size categories, but the body condition of blue tit nestlings and the size of great tit nestlings did, being significantly better and larger respectively in large forest patches. The recruitment rate of blue tit nestlings was also higher in large patches. Regarding nestling diet, blue tits did not differ but great tits did, delivering a larger amount of caterpillars in large forest patches. Most variation in the reproductive traits occurred between years, probably due to annual differences in environmental conditions. This study suggests that food supply could be limiting the breeding success of birds above all in small patches, but also in large patches under particular environmental conditions.Funding was provided by Ministerio de Ciencia e Innovación (CGL2010-21933-C02-01) and Junta de Comunidades de Castilla-La Mancha and European Social Fund (POIC10-0269-7632). ESF and JBE are both supported by a doctoral scholarship from Junta de Comunidades de Castilla-La Mancha-European Social Fund. RB benefited from the JCCM-FSE 2007/2013 postdoctoral program and from a “Juan de la Cierva” post-doctoral contract (JCI-2011-10945) and ESD enjoyed a pre-doctoral fellowship from Ministerio de Ciencia e Innovación.Peer reviewe

Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation

Efecto del medioambiente sobre la biología reproductiva de dos especies de aves insectívoras forestales en los Montes de Toledo

El fenotipo de las poblaciones animales que observamos está altamente influenciado por las condiciones del medio ambiente donde dichas poblaciones viven. Por lo tanto, para entender en profundidad las características de una población es necesario saber las presiones del medio ambiente que dicha población está soportando. Conocer el papel que el medio ambiente tiene sobre el fenotipo de los individuos que componen una población no es sólo importante a nivel de investigación básica, si no que reviste de gran importancia para su conservación, porque sólo de este modo sabremos de qué manera el medio ambiente afecta a la eficacia biológica de las individuos de las poblaciones y podremos predecir y adelantarnos a cambios que se produzcan en el medio ambiente, tales como el cambio global que actualmente acontece en el planeta. Con este objetivo, durante la primavera de tres años consecutivos (2011-2013), estudiamos el efecto de cambios medio ambientales sobre la biología reproductiva de dos poblaciones simpátricas de Carbonero común (Parus major) y Herrerillo común (Cyanistes caeruleus) en el municipio de San Pablo de los Montes (Toledo, España). En concreto estudiamos el efecto del tamaño del parche forestal (debido a la fragmentación del hábitat) y el tipo de cavidad (caja nido) sobre la biología reproductiva de ambas poblaciones. También estudiamos el efecto de las propiedades acústicas del hábitat, concretamente el nivel de ruido ambiental y la estructura del hábitat, sobre las características del canto del Carbonero común, debido a que éste es un rasgo fundamental en su biología por su papel en la selección sexual. Además, estudiamos el efecto de las condiciones climáticas propias de nuestra latitud sobre el comportamiento de incubación de ambas especies. Por último estudiamos el marco ecológico en el que se producen ausencias prolongadas en el cuidado de los huevos durante la incubación, pues probablemente indican condiciones extremadamente limitantes para las hembras incubadoras, lo que puede tener consecuencias sobre su propia eficacia biológica y la de los pollos. Los resultados de nuestro estudio confirmaron que, efectivamente, el fenotipo de los individuos en nuestras poblaciones de Carbonero y Herrerillo común estaba condicionado por el medio ambiente y que ambas poblaciones fueron capaces de responder plásticamente a dichos cambios ambientales para amortiguar sus efectos. Así, la calidad de los pollos a los 13 días de edad en ambas especies estuvo condicionada por el tamaño del parche forestal donde fueron criados, siendo peor en los parches forestales pequeños (capítulo I). El tipo de caja nido utilizado para anidar también influyó en la biología reproductiva de ambas especies. En las cajas nido de cemento los nidos fueron más altos, los huevos más pequeños y los pollos tenían un ala más corta a los 13 días de edad. En dichas cajas nido la fecha de puesta se adelantó alrededor de una semana, la atención al nido durante la incubación disminuyó así como el éxito reproductor de las parejas criando en ellas, debido a una mayor tasa de depredación en ese tipo de cajas y posiblemente a unas mayores condiciones de hipertermia (capítulo II). Ciertas características del canto de los Carboneros comunes se relacionaron con las propiedades acústicas en cada hábitat. Así, en el capítulo III comparamos los cantos entre Toledo y dos poblaciones forestales cercanas. Dicha comparación reveló que los Carboneros comunes en Toledo cantaban más rápido y con una frecuencia pico y máxima mayor que sus conspecíficos en zonas forestales, además aumentaron el uso de notas con una frecuencia pico mayor. Los Carboneros comunes también ajustaron las características de su canto dentro de la misma población según la estructura del hábitat en cada territorio. En los territorios con una mayor cobertura de matorral cantaron más despacio y con una frecuencia mínima menor, mientras que en los territorios con una mayor proporción de suelo desnudo incrementaron la longitud de sus estrofas (capítulo IV). La estrategia de incubación de nuestra población de Carboneros comunes difirió de la estrategia mostrada en poblaciones más norteñas, posiblemente debido a la variación climática latitudinal, y también difirió de la estrategia de incubación de los Herrerillos comunes, pese a que ambas especies proporcionaron la misma atención a sus huevos (capítulo V). De entre todos los patrones de incubación registrados en las dos especies, aproximadamente el 12 % de ellos presentaban al menos una ausencia del nido extremadamente larga, en donde la temperatura del termómetro situado entre los huevos descendía muy por debajo del límite fisiológico cero de ambas especies. En este tipo de patrones de incubación, la atención proporcionada por las madres era inferior que en los patrones donde dichas ausencias prolongadas no aparecían. Este comportamiento negligente se produjo con mayor frecuencia en el año y la especie que las hembras presentaban peor condición corporal (2012 y Herrerillos comunes respectivamente) y en las cajas nido de cemento más que en las de madera. Además normalmente se producía después de noches largas y frías, lo que hace pensar que las ausencias prolongadas del nido durante la incubación suceden debido a limitaciones energéticas de las madres incubadoras. El periodo de incubación en dichas puestas donde se produjo al menos una ausencia prolongada se alargó en promedio cuatro días (capítulo VI). En rasgos generales, ambas poblaciones de páridos mostraron que son susceptibles a los cambios en su medio ambiente y pese a que son capaces de responder plásticamente a dichos cambios ambientales, su eficacia biológica se vio comprometida en algunas ocasiones

Hatching asynchrony vs. foraging efficiency: the response to food availability in specialist vs. generalist tit species

Breeding mistiming is increasingly frequent in several ecosystems in the face of current climate change. Species belonging to higher trophic levels must employ mechanisms to reduce it. One of these mechanisms is hatching asynchrony, with the eggs in a clutch hatching over a period of several days. Some authors have suggested it to be adaptive when food is unpredictable. However, these birds can also suffer associated costs. We tested whether a species with higher foraging efficiency avoid hatching asynchrony compared to its sister species. We studied hatching asynchrony and nestling provisioning in relation to food availability in sympatric populations of blue and great tits. For the first time, we show that sister species respond to food availability with different strategies. Blue tit feeding rates readily responded to the abundance of their main prey, and also reduced the impact of nestling size hierarchy on mean nestling weight, consequently increasing fledging rate. Our results suggest that levels of hatching asynchrony seem to be influenced by species-specific life history traits, as generalist foragers rely less on it. They also highlight the importance of multi-species approaches when studying the response of organisms to environmental unpredictability.Peer Reviewe

Cultural transmission and its possible effect on urban acoustic adaptation of the great tit Parus major

[EN] Urban great tits (Parus major) sing with a higher minimum frequency than their forest conspecifics. Cultural processes may account at least in part for the song divergence in city birds as great tits learn their repertoire from conspecifics and switch to high pitch song types in presence of background noise. However, in small cit ies, this process of cultural divergence could be constrained because it is likely that these birds have a greater exchange of song types with the outside. We tested this prediction by recording great tit songs in a small city (Toledo, central Spain) and in a nearby forest. We found that background noise and the peak and the maximum frequency of songs were higher in the city but the minimum frequency did not differ. The pause length was also longer in forest birds. Seventy percent of the song types were shared between Toledo and the nearby forest. These results suggest that the small size of Toledo allows a homogenized cultural wealth, preventing the devel opment of a high pitch song as observed in larger cities.[ES] El carbonero común (Parus major) urbano canta con una frecuencia mínima mayor que sus conspecíficos forestales. Detrás de esta divergencia acústica podrían estar algunos procesos culturales, ya que dichas aves aprenden sus cantos de los vecinos y cambian a tipos de canto con una frecuencia alta en presencia de ruido de fondo. Sin embargo, en las ciudades pequeñas este proceso de divergencia cultural podría estar limitado, ya que en dichas ciudades es esperable un alto grado de intercambio de tipos de canto con el exterior. Nosotros testamos esta predicción grabando cantos de carbonero común en una ciudad pequeña (Toledo, España) y en un bosque cercano. El ruido de fondo fue más alto en la ciudad, al igual que la frecuencia "pico" y máxima de los cantos, pero la frecuencia mínima no difirió. La longitud de la pausa fue mayor en el bosque. El setenta por ciento de los tipos de canto se compartieron entre Toledo y el bosque cercano. Estos resultados sugieren que el pequeño tamaño de Toledo impide el establecimiento de una tradición de cantos particular con una frecuencia alta como se observa en ciudades más grandes.Peer reviewe

Effects of flow regulation and non-native species on feeding habits of eurasian otter Lutra Iutra in Mediterranean temporary rivers

In Mediterranean temporary rivers, ecological resources greatly fluctuate because of the high hydrological variability throughout the year. However, flow regulation prevents this natural regime and commonly entails associated non-native species, which change the structure of aquatic communities. Nonetheless, few studies have tested the interaction of these two disruptive factors (flow regulation and non-native species) and their synergistic effects on the Eurasian otter (Lutra lutra) diet at the river scale. The aim of this study was to compare the seasonal feeding habits of the otter between a temporary non-regulated stretch and two regulated stretches invaded by non-native species in a Mediterranean water course. The Bullaque River (Guadiana River Basin, central Spain) was seasonally sampled for otter spraints and prey abundance assessed from December 2009 to November 2010. Three stretches were considered: high (source, non-regulated), medium (transition, regulated) and low (confluence, regulated). Diet varied from native prey in the high stretch (amphibians, insects and endemic cyprinids) to non-native species in the low stretch (red-swamp crayfish Procambarus clarkii and pumpkinseed sunfish Lepomis gibbosus). Seasonally, ingested biomass of native prey increased in spring. Diet was more diverse in the high stretch. Otters neutrally selected native cyprinids in the high stretch throughout the year, whereas crayfish was selected in the other two stretches. Overall results showed that flow regulation and non-native species have increased prey availability for the otter; however, this paper highlights the importance of maintaining natural regimes in Mediterranean temporary rivers to conserve native communities and thus minimally impact food webs in Iberian freshwaters.This study has been possible thanks to the funding of the project: ‘Convenio entre Confederación Hidrográfica del Guadiana y la UCLM para el desarrollo de estudios de investigación y seguimiento de las medidas ambientales de restauración fluvial del río Bullaque’. J. B .E. held a pre-doctoral fellowship from Junta de Comunidades de Castilla-La Mancha.Peer Reviewe

Incubation behaviour of Blue Cyanistes caeruleus and Great Tits Parus major in a Mediterranean habitat

The incubation stage in avian reproduction could be as costly as the nestling rearing stage. This is particularly true in the case of uniparental incubation, during which both current and future breeding attempts may be compromised. Therefore, the knowledge of the proximate effects that condition the incubation behaviour in free-living bird populations is of great importance in understanding the evolution of avian life history. In this two-year study, we assessed the incubation behaviours of Blue Cyanistes caeruleus and Great Tits Parus major inhabiting the same Mediterranean area in central Spain through the usage of iButton data loggers. It showed that the incubating behaviour of our tit populations resembles that reported in previous studies, but with peculiarities related to living at lower latitudes, i.e. with a relatively low attentiveness and a shorter active day. Both tit species showed very different incubation strategies, with Blue Tits leaving more frequently the nest (Mean ± SE number of off-bouts, Blue Tit = 27.14 ± 0.63, Great Tit = 16.95 ± 0.58) but for shorter periods than Great Tits (off-bout duration, Blue Tit = 8.76 ± 0.22 min, Great Tit = 14.04 ± 0.56 min; on-bout duration, Blue Tit = 22.63 ± 0.60 min, Great Tit = 36.86 ± 0.86 min). Nonetheless, both species provided a similar nest attentiveness, percentage of time of the active day during which the females were actively incubating (Blue Tit = 70.87 ± 0.57%, Great Tit = 70.75 ± 0.83%). Presumably, differences in the cooling rate of clutches, estimated with the iButtons, could be behind the differences in incubation behaviour between species and the greater capacity of Great Tits to adjust their incubation behaviour.Funding was provided by Ministerio de Economía y Competitividad (CLG2013-48001-C2-1P) and Junta de Comunidades de Castilla-La Mancha and European Social Fund (POIC10-0269- 7632). JBE is supported by a doctoral scholarship from the Junta de Comunidades de Castilla-La Mancha-European Social Fund and RB is a part of the JCCM-FSE 2007/2013 postdoctoral program and has a “Juan de la Cierva” post-doctoral contract (JCI-2011-10945).Peer Reviewe

Extrapair paternity in Mediterranean blue tits: socioecological factors and the opportunity for sexual selection

The frequency of extrapair paternity within populations has been hypothesized to be related to ecological and social factors, which in turn can determine the impact of extrapair paternity on the opportunity for sexual selection. Here, we use the blue tit Cyanistes caeruleus as study species to assess both issues. In particular, we analyze patterns of extrapair paternity in 12 nest-box plots that greatly vary in local population size, level of nest-box aggregation, and breeding density. We found a significant positive relationship between extrapair paternity rate and local population size. Within study plots, neither local breeding density nor synchrony had an effect on the occurrence of extrapair paternity. Most extrapair males engaged in extrapair copulations with neighbouring females, probably in order to avoid paternity losses. Individuals that travelled larger distances to gain extrapair paternity likely did so because the social females of most of them had not yet begun their fertile period and, thus, within-pair paternity was not at risk. Variance in male reproductive success was mostly produced by variance in within-pair success, which in turn was primarily influenced by mate quality. Extrapair success contributed substantially to variance in male reproductive success (26%), but its effect was smaller than expected. Bateman gradients showed positive slopes (βss) for both males and females. However, the lack of a positive covariance between within-pair and extrapair success suggests that the effect of extrapair paternity on the strength of sexual selection was limited. This fact can be explained by the spatial distribution of extrapair fertilizations, which points to the absence of directional female mating preferences in this study system and, thus, not leading to “big winners” and “big losers.”This work was supported by Ministerio de Ciencia e Innovación (grant CGL2010-21933-C02-01) and Junta de Comunidades de Castilla-La Mancha and European Social Fund (grant POIC10-0269-7632). V.G.N. enjoyed a predoctoral fellowship from Ministerio de Ciencia e Innovación and European Social Fund.Peer reviewe