Estudio de la comunidad de Falconiformes de la provincia de Ourense. Con mención especial para sus sierras suroccidentales

Se aportó información descriptiva sobre la comunidad de Falconiformes en la provincia de Ourense, en relación a su diversidad, abundancia, densidad y estimas poblacionales. Se hizo mención especial para las sierras suroccidentales (Baixa Limia), donde se incidió en el conocimiento de la distribución local. En la provincia de Ourense se detectaron un total de 22 especies de Falconiformes. En 13 de ellas se confirmó la cría, otra se consideró como de cría probable y 3 de cría posible. Siete de éstas fueron residentes, seis estivales y una invernante. El estatus de las restantes no está claro, tratándose de migradoras dispersivas o accidentales. Se analizó el estado de las poblaciones de Perdiz roja (Alectoris rufa), Liebre ibérica (Lepus granatensis) y Conejo (Oryctolagus cuniculus) en las sierras suroccidentales de Ourense (Baixa Limia). Se desarrollaron patrones de distribución y selección de hábitat a nivel de macroescala. Se discutieron las posibles repercusiones que sobre las Falconiformes presentes tiene el estado de estas especies-presa, así como los conflictos existentes en la conservación de ambas, estableciendo estrategias de gestión para éstas. Se caracterizó la comunidad de Falconiformes del piso montano en las sierras suroccidentales de Ourense a lo largo de un ciclo anual y analizaron los patrones de selección de hábitat de caza específicos durante los períodos reproductivo y post-reproductivo. Se discutió cómo influyen las variables ambientales analizadas en la presencia, abundancia y riqueza de las diferentes Falconiformes en dichos períodos. Se proponen medidas de conservación y manejo del hábitat que podrían favorecer a las especies presentes. Se modelizó la selección de hábitat por parte de las Falconiformes a dos escalas espaciales: LIC Baixa-Limia y provincia de Ourense. Se discutieron los patrones de selección de hábitat obtenidos, analizando el efecto de la escala en la selección de hábitat y evaluando la efectividad de las dos técnicas de censo empleadas para llevar a cabo dichos estudios. Igualmente se discutieron las implicaciones y aplicaciones prácticas de estos modelos en la conservación de las rapaces diurnas de Ourense. A ambas escalas de análisis en los modelos obtenidos a partir de los datos de distribución estuvieron implicadas un total de 13 variables, siendo la superficie de matorral la que explicó la distribución de un mayor número de especies, un total de 6. En los modelos obtenidos a partir de un Índice de Categoría de Cría y de abundancias estuvieron implicadas un total de 14 variables, siendo la Altura mínima, Superficie de matorral y Longitud de borde entre matorral y embalse las variables que entraron en los modelos de un mayor número de especies, un total de 4. Se analizó la situación del Águila real (Aquila chrysaetos) en la provincia de Ourense, así como sus patrones de distribución y de selección de hábitat. Se predijeron las áreas de distribución potencial a partir de datos de áreas de nidificación conocidas, actuales y antiguas, elaborando modelos cartográficos identificadores de las áreas de hábitat potencialmente más adecuado y prioritarias para la conservación. Se analizaron y discutieron los problemas de conservación asociados a las limitaciones del propio medio y que podrían estar condicionando su capacidad de carga. La población de Águila real en Ourense se encuentra limitada por la escasez de cortados rocosos, la presión humana y la escasa disponibilidad de presas. En las últimas décadas las repoblaciones forestales masivas, con apertura incontrolada de pistas y cortafuegos, ocasionaron importantes perturbaciones en las áreas de cría. Esta población pudo alcanzar sus mínimos a finales de la década de 1980, probablemente por la mortandad experimentada a causa del veneno y la persecución directa en décadas anteriores. Los modelos obtenidos para las áreas actuales de nidificación, antiguas y una combinación de ambas, incluyeron 7 variables ambientales. Las variables topográficas asociadas a los relieves más escarpados y montañosos fueron las que más condicionaron la presencia de áreas de cría en la actualidad. El modelo final más parsimonioso obtenido incluyó con valor positivo la Altura máxima

Caution Is Needed When Using Niche Models to Infer Changes in Species Abundance: The Case of Two Sympatric Raptor Populations

Despite the mounting evidence supporting positive relationships between species abundance and habitat suitability, the capacity of ecological niche models (ENMs) to capture variations in population abundance remains largely unexplored. This study focuses on sympatric populations of hen harrier (Circus cyaneus) and Montagu’s harrier (Circus pygargus), surveyed in 1997 and 2017 in an upland moor area in northwestern Spain. The ENMs performed very well for both species (with area under the ROC curve and true skill statistic values of up to 0.9 and 0.75). The presence of both species was mainly correlated with heathlands, although the normalized difference water index derived from Landsat images was the most important for hen harrier, indicating a greater preference of this species for wet heaths and peat bogs. The findings showed that ENM-derived habitat suitability was significantly correlated with the species abundance, thus reinforcing the use of ENMs as a proxy for species abundance. However, the temporal variation in species abundance was not significantly explained by changes in habitat suitability predicted by the ENMs, indicating the need for caution when using these types of models to infer changes in population abundanceThis work received funding from Xunta de Galicia through the grant to structure and consolidate competitive research groups of Galicia (ED431B 2018/36). A.R. was funded by the Xunta de Galicia, Spain (postdoctoral fellowship ED481B2016/084-0)S

Monitoring protected areas from space: A multi-temporal assessment using raptors as biodiversity surrogates

Monitoring protected areas (PAs) is essential for systematic evaluation of their effectiveness in terms of habitat protection, preservation and representativeness. This study illustrates how the use of species distribution models that combine remote sensing data and information about biodiversity surrogates can contribute to develop a systematic protocol for monitoring PAs. In particular, we assessed the effectiveness of the Natura 2000 (N2000) network, for conserving and preserving the representativeness of seven raptor species in a highly-dynamic landscape in northwest Spain between 2001 and 2014. We also evaluated the cost-effectiveness of the N2000 network by using the total area under protection as a proxy for conservation costs. Overall, the N2000 network was found to poorly represent the habitats of the raptor species. Despite the low representativeness, this network showed a high degree of effectiveness due to increased overall habitat availability for generalist and forest specialist species between 2001 and 2014. Nevertheless, additional protected areas should be established in the near future to increase their representativeness, and thus ensure the protection of open-habitat specialist species and their priority habitats. In addition, proactive conservation measures in natural and semi-natural ecosystems (in particular, montane heathlands) will be essential for long-term protection of Montagu’s harrier (species listed in the Annex I of the Bird Directive), and thus complying with the current European Environmental Legislation. This study sheds light on how the development and application of new protected area indices based on the combined use of freely-available satellite data and species distribution models may contribute substantially to the cost-efficiency of the PA monitoring systems, and to the ‘Fitness Check’ process of EU Nature DirectivesThis work was partly funded by the EU BON (308454; FP7-ENV-2012, European Commission), FORESTCAST (CGL2014-59742) and NEWFORESTS (EU Seventh Framework Programme, PIRSES-GA-2013-612645) projects. A.R. was funded by the Xunta de Galicia (post-doctoral fellowship ED481B2016/084-0). Fieldwork was partially supported by the Department of Environment of Galician Government through the PGIDTO1MAM20001PR (Xunta de Galicia) projectS

Model-Assisted Bird Monitoring Based on Remotely Sensed Ecosystem Functioning and Atlas Data

Urgent action needs to be taken to halt global biodiversity crisis. To be effective in the implementation of such action, managers and policy-makers need updated information on the status and trends of biodiversity. Here, we test the ability of remotely sensed ecosystem functioning attributes (EFAs) to predict the distribution of 73 bird species with different life-history traits. We run ensemble species distribution models (SDMs) trained with bird atlas data and 12 EFAs describing different dimensions of carbon cycle and surface energy balance. Our ensemble SDMs—exclusively based on EFAs—hold a high predictive capacity across 71 target species (up to 0.94 and 0.79 of Area Under the ROC curve and true skill statistic (TSS)). Our results showed the life-history traits did not significantly affect SDM performance. Overall, minimum Enhanced Vegetation Index (EVI) and maximum Albedo values (descriptors of primary productivity and energy balance) were the most important predictors across our bird community. Our approach leverages the existing atlas data and provides an alternative method to monitor inter-annual bird habitat dynamics from space in the absence of long-term biodiversity monitoring schemes. This study illustrates the great potential that satellite remote sensing can contribute to the Aichi Biodiversity Targets and to the Essential Biodiversity Variables framework (EBV class “Species distribution”)Fieldwork campaigns were carried out within the project “Estudios sobre a biodiversidade do Macizo Central Galego. Lugar de Importancia Comunitaria” (PGIDT99PXI20002B) and “Caracterización de los vertebrados del LIC Macizo Central e Bidueiral de Montederramo”, code: 2008-CE227”, funded by SAYFOR S.L. This work also received funding from Xunta de Galicia through the grant to structure and consolidate competitive research groups of Galicia (ED431B 2018/36). A.R. was funded by the Xunta de Galicia, Spain (post-doctoral fellowship ED481B2016/084-0). S.A.-C. was financially supported by PORBIOTA—E-Infraestrutura Portuguesa de Informação e Investigação em Biodiversidade (POCI-01-0145-FEDER-022127)S

A search for ultra-high-energy photons at the Pierre Auger Observatory exploiting air-shower universality

The Pierre Auger Observatory is the most sensitive detector to primary photons with energies above ∼0.2 EeV. It measures extensive air showers using a hybrid technique that combines a fluorescence detector (FD) with a ground array of particle detectors (SD). The signatures of a photon-induced air shower are a larger atmospheric depth at the shower maximum (X$_{max}$) and a steeper lateral distribution function, along with a lower number of muons with respect to the bulk of hadron-induced background. Using observables measured by the FD and SD, three photon searches in different energy bands are performed. In particular, between threshold energies of 1-10 EeV, a new analysis technique has been developed by combining the FD-based measurement of X$_{max}$ with the SD signal through a parameter related to its muon content, derived from the universality of the air showers. This technique has led to a better photon/hadron separation and, consequently, to a higher search sensitivity, resulting in a tighter upper limit than before. The outcome of this new analysis is presented here, along with previous results in the energy ranges below 1 EeV and above 10 EeV. From the data collected by the Pierre Auger Observatory in about 15 years of operation, the most stringent constraints on the fraction of photons in the cosmic flux are set over almost three decades in energy

Study on multi-ELVES in the Pierre Auger Observatory

Since 2013, the four sites of the Fluorescence Detector (FD) of the Pierre Auger Observatory record ELVES with a dedicated trigger. These UV light emissions are correlated to distant lightning strikes. The length of recorded traces has been increased from 100 μs (2013), to 300 μs (2014-16), to 900 μs (2017-present), to progressively extend the observation of the light emission towards the vertical of the causative lightning and beyond. A large fraction of the observed events shows double ELVES within the time window, and, in some cases, even more complex structures are observed. The nature of the multi-ELVES is not completely understood but may be related to the different types of lightning in which they are originated. For example, it is known that Narrow Bipolar Events can produce double ELVES, and Energetic In-cloud Pulses, occurring between the main negative and upper positive charge layer of clouds, can induce double and even quadruple ELVES in the ionosphere. This report shows the seasonal and daily dependence of the time gap, amplitude ratio, and correlation between the pulse widths of the peaks in a sample of 1000+ multi-ELVES events recorded during the period 2014-20. The events have been compared with data from other satellite and ground-based sensing devices to study the correlation of their properties with lightning observables such as altitude and polarity