Discard-ban policies can help improve our understanding of the ecological role of food availability to seabirds

ACKNOWLEDGEMENTS Funds for this study were supplied by the Spanish Ministry of Economy and by the European Social Fund (grant ref.: CGL2013-42203-R). The study also received funding from the European Commission’s Horizon 2020 Research and Innovation Programme under Grant Agreement no. 634495 for the project Science, Technology, and Society Initiative to Minimize Unwanted Catches in European Fisheries (MINOUW). MG and ASA are supported by postdoctoral contracts co-funded by the Regional Government of the Balearic Islands and the European Social Fund. Two reviewers helped to improve the manuscript.Peer reviewedPublisher PD

Estimating recruitment and survival in partially monitored populations

In evolutionary and ecological studies, demographic parameters are commonly derived from detailed information collected on a limited number of individuals or in a confined sector of the breeding area. This partial monitoring is expected to underestimate survival and recruitment processes because individuals marked in a monitored location may move to or recruit in an unobservable site. We formulate a multi-event capture-recapture model using E-SURGE software which incorporates additional information on breeding dispersal and the proportion of monitored sites to obtain unbiased estimates of survival and recruitment rates. Using simulated data, we assessed the biases in recruitment, survival and population growth rate when monitoring 10-90% of the whole population in a short- and a long-lived species with low breeding dispersal. Finally, we illustrate the approach using real data from a long-term monitoring program of a colony of Scopoli's shearwaters Calonectris diomedea. We found that demographic parameters estimated without considering the proportion of the area monitored were generally underestimated. These biases caused a substantial error in the estimated population growth rate, especially when a low proportion of breeding individuals were monitored. The proposed capture-recapture model successfully corrected for partial monitoring and provided robust demographic estimates. Synthesis and applications. In many cases, animal breeding populations can only be monitored partially. Consequently, recruitment and immature survival are underestimated, but the extent of these biases depends on the proportion of the area that remains undetected and the degree of breeding dispersal. We present a new method to obtain robust and unbiased measures of survival and recruitment processes from capture-recapture data. The method can be applied to any monitored population regardless of the type of nests (e.g. artificial or natural) or breeding system (e.g. colonial or territorial animals), and it only relies on an estimate of the proportion of the monitored area. The unbiased estimates obtained by this method can be used to improve the reliability of predictions of demographic population models for species' conservation and management.Research funds were provided by the Spanish Ministries of Science, Economy and Competitiveness (refs. BOS2003-01960, CGL2006-04325/BOS, CGL2009-08298, CGL2013-42203-R, JCI-2011-09085)Peer Reviewe

Efectividad de las políticas públicas en el proceso de transición energética en cuencas carboníferas aragonesas. Un análisis desde la combinación de políticas

Con el cierre de las minas y las centrales térmicas dedicadas a la extracción del carbón, varias comarcas aragonesas históricamente dependientes del carbón, Cuencas Mineras y Andorra-Sierra de Arcos, han tenido que reinventarse para poder sustituir la economía del carbón manteniendo ingresos, población y servicios, con el apoyo de planes, estrategias y programas que forman parte de un conjunto de políticas públicas que vienen desarrollándose desde los años 90. Nos preguntamos si han sido lo suficientemente efectivas y han cumplido con los objetivos por los cuales han sido creadas. Focalizando el análisis en la combinación de políticas y poniendo en relación tres ámbitos esenciales: económico, demográfico y territorial, el nuevo uso de los suelos. Se concluye que tras los sucesivos programas que se han ido instaurando en los territorios analizados, estos, no han tenido el resultado esperado y por ende, no han sabido sustituir, en su totalidad, la economía del carbón. Si bien las políticas públicas han sido efectivas en la reducción del empleo, producción y consumo del carbón, no lo han sido tanto en evitar los impactos negativos sobre las personas y el territorio.<br /

Multi-event capture-recapture analysis reveals individual foraging specialization in a generalist species

© 2015 by the Ecological Society of America. Populations of species typically considered trophic generalists may include specialized individuals consistently feeding on certain resources. Optimal foraging theory states that individuals should feed on those resources most valuable to them. This, however, may vary according to individual differences in detecting or processing resources, different optimization criteria, and competitive abilities. White Storks (Ciconia ciconia) are trophic generalists at the population level. Their European population recovery has been attributed to increased wintering in southern Europe (rather than Africa) where they feed upon new anthropogenic food subsidies: predictable dumps and less predictable and more difficult to detect, but abundant, invasive Procambarus clarkii crayfishes in ricefields. We studied the foraging strategies of resident and wintering storks in southwestern Spain in ricefields and dumps, predicting that more experience in the study area (residents vs. immigrants, old vs. young) would increase ricefield specialization. We developed the first multi-event capture- recapture model to evaluate behavioral consistency, analyzing 3042 observations of 1684 banded storks. There were more specialists among residents (72%) than immigrants (40%). All resident specialists foraged in ricefields, and ricefield use increased with individual age. In contrast, some immigrants specialized on either dumps (24%) or ricefields (16%), but the majority were generalists (60%). Our results provide empirical evidence of high individual foraging consistency within a generalist species and a differential resource selection by individuals of different ages and origins, probably related to their previous experience in the foraging area. Thus, future changes in food resource availability at either of the two anthropogenic subsidies (ricefields or dumps) may differentially impact individuals of different ages and origins making up the wintering population. The use of multi-event capture- recapture modeling has proven useful for studying interindividual variability in behavior.Peer Reviewe

Can Establishment Success Be Determined through Demographic Parameters? A Case Study on Five Introduced Bird Species

The dominant criterion to determine when an introduced species is established relies on the maintenance of a self-sustaining population in the area of introduction, i.e. on the viability of the population from a demographic perspective. There is however a paucity of demographic studies on introduced species, and establishment success is thus generally determined by expert opinion without undertaking population viability analyses (PVAs). By means of an intensive five year capture-recapture monitoring program (involving \u3e12,000 marked individuals) we studied the demography of five introduced passerine bird species in southern Spain which are established and have undergone a fast expansion over the last decades. We obtained useful estimates of demographic parameters (survival and reproduction) for one colonial species (Ploceus melanocephalus), confirming the long-term viability of its local population through PVAs. However, extremely low recapture rates prevented the estimation of survival parameters and population growth rates for widely distributed species with low local densities (Estrilda troglodytes and Amandava amandava) but also for highly abundant yet non-colonial species (Estrilda astrild and Euplectes afer). Therefore, determining the establishment success of introduced passerine species by demographic criteria alone may often be troublesome even when devoting much effort to field-work. Alternative quantitative methodologies such as the analysis of spatio-temporal species distributions complemented with expert opinion deserve thus their role in the assessment of establishment success of introduced species when estimates of demographic parameters are difficult to obtain, as is generally the case for non-colonial, highly mobile passerines

Interspecific synchrony on breeding performance and the role of anthropogenic food subsidies

Open Access via the PLOS Flat Fee Agreement Funding: This work has been partially supported by Balearic Government, Ministry of Education (FPU2012-000869), Ministry of Economy (IBISES-CGL2013-42203-R and RESET-CGL2017-85210-P) and EU project MINOW (H2020-634495). It was partially funded by the EU FEDER regional funds. ASA was supported by a Ramón y Cajal contract (RYC-2017- 22796) funded by the Ministerio de Ciencia, Innovación y Universidades, the Agencia Estatal de Investigación and the ESF. MG was supported by a postdoctoral contract co-funded by the Regional Government of the BI and the ESF (PD/023/2015). There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Oceanographic drivers and mistiming processes shape breeding success in a seabird

Understanding the processes driving seabirds’ reproductive performance through trophic interactions requires the identification of seasonal pulses in marine productivity.We investigated the sequence of environmental and biological processes driving the reproductive phenology and performance of the storm petrel (Hydrobates pelagicus) in the Western Mediterranean. The enhanced light and nutrient availability at the onset of water stratification (late winter/early spring) resulted in annual consecutive peaks in relative abundance of phytoplankton, zooplankton and ichthyoplankton. The high energy-demanding period of egg production and chick rearing coincided with these successive pulses in food availability, pointing to a phenological adjustment to such seasonal patterns with important fitness consequences. Indeed, delayed reproduction with respect to the onset of water stratification resulted in both hatching and breeding failure. This pattern was observed at the population level, but also when confounding factors such as individuals’ age or experience were also accounted for.We provide the first evidence of oceanographic drivers leading to the optimal time-window for reproduction in an inshore seabird at southern European latitudes, along with a suitable framework for assessing the impact of environmentally driven changes in marine productivity patterns in seabird performance.Research funds were provided by the Spanish Government (refs. BOS2003-01960, CGL2006-04325/BOS, CGL2009 08298, CGL2013-42203-R, JCI-2011-09085), and the European Union (FP7-PEOPLE 2009-IEF-MATERGLOBE)Peer Reviewe

The relative contribution of camera trap technology and citizen science for estimating survival of an endangered African vulture

Technological advances such as camera traps, and citizen science, coupled with advanced quantitative approaches, can help fill existing knowledge gaps and aid effective conservation. We combine citizen and camera trap observations to estimate survival of the Endangered lappet-faced vulture, assess the relative contribution of data from camera traps and citizens, as well as impact of loss of individual marks (wing tags), on survival estimates. We used data from 762 lappet-faced vultures wing tagged as nestlings during 2006–2017 in western Namibia. Observations of wing tagged individuals were provided by citizens or via camera traps. We formulated a multievent capture-mark-recapture model to estimate survival while accounting for probabilities of resighting by citizens and/or camera traps, recovery of dead individuals, and loss of the wing tag. Survival was relatively high for juveniles (0.79), and increased with age to 0.95. Citizen observations of live and dead birds were low in number. However, when combined with camera trap resightings of live individuals, citizen observations increased the precision of survival estimates of birds older than one year compared to using data from either sources separately. Wing tag loss was high after 5–6 years of tag age. If neglected, tag loss can result in severe underestimation of survival of the older age classes. Overall, we show that filling ecological knowledge gaps is possible through the efficient use of data provided by different sources, and by applying state-of the art approaches that minimise potential biases, such as those due to tag loss.Peer reviewe

Blind shots: non-natural mortality counteracts conservation efforts of a threatened waterbird

Waterbirds are particularly affected by the high hunting pressure they face in many regions, which in some cases is compromising conservation actions for threatened species. The marbled teal Marmaronetta angustirostris is one of the most endangered waterbirds in Europe. In order to restore its population, several conservation actions have recently been undertaken, including a population reinforcement programme in Spain using captive-bred birds. With the aim of assessing the success of the reinforcement programme to establish a long-term self-sustaining population, we identified mortality causes of marbled teal, evaluated the survival of individual birds of the reinforcement programme and estimated the viability of the population under different management scenarios. We used data from wild and captive-bred individuals tracked by GPS since 2018 (n = 42) and from a mark–recapture programme initiated in 2015 (n = 297). We recovered 15 dead birds or transmitters: 20% died of natural causes, 60% of non-natural causes (including all anthropic causes) and 20% of unknown causes. Furthermore, the GPS tags of 24 birds unexpectedly stopped transmitting without any indication of malfunction, and for 66.7% of these disappeared birds, the cessation was suspected to be caused by illegal shooting. Survival during the hunting season was higher for males (31.3%) than for females (12.5%), and for the wild (50%) than for the captive-bred birds (9.4%), probably due to differences in migration patterns to North Africa. Population viability models revealed that maintaining the breeding population at the current mortality rates is only possible with a permanent release programme of captive-bred individuals, and that in order to establish a self-sustaining population, non-natural mortality would have to be reduced by at least 40%. We recommend management measures to reduce marbled teal mortality, such as limiting legal hunting to hours with clear visibility, prosecuting illegal shootings, controlling exotic predators and improving water management to reduce disease outbreaks. Some improvements can be implemented in captive-breeding programmes, such as earlier release times and incorporating anti-predator training.The transmitters were funded by the Generalitat Valenciana, the Ministry for Ecological Transition and the Biodiversity Foundation. JMPG was supported by a Spanish Ministry of Science, Innovation and Universities postdoctoral contract IJC-2019-038968 funded by MCIN/AEI/10.13039/501100011033. ESG and ASA received the grants RYC2019-027216-I and RYC-2017-22796 funded by MCIN/AEI/10.13039/501100011033 and by ESF Investing in your future. RCRC was supported by the European Union-Next Generation EU in the Maria Zambrano Program (ZAMBRANO 21-26). The present research was carried out within the framework of the activities of the Spanish Government through the ‘Maria de Maeztu Centre of Excellence’ accreditation to IMEDEA (CSIC-UIB) (CEX2021-001198)