Etude du régime alimentaire de la Chouette effraie Tyto alba (Strigiforme,Tytonidae) dans la région de Lalla Mimouna dans la plaine du Gharb, plaine du Maroc atlantique

Nous présentons dans ce travail les résultats de l’analyse du régime alimentaire d’un rapace nocturne (la Chouette effraie Tyto alba) dans les plaines du Maroc atlantique à partir de plusieurs lots de pelotes de réjection collectées en 2012. Il s’agit de deux régions de la plaine du Gharb, une située dans un milieu forestier anthropisé (Sidi Boubker El Haj) et l’autre en plein milieu irrigué et intensément cultivé (domaine des Drader à Moulay Bousselhame). L’étude des pelotes a fournie 1285 proies réparties sur plusieurs groupes zoologiques formants l’essentiel du régime de ce rapace. Les mammifères sont beaucoup plus représentés avec environ 64% de ce régime, les insectes sont représentés avec plus de 27% alors que les oiseaux et les amphibiens forment moins de 10%. Ce régime diffère fortement de celui des effraies des plaines semi-arides du Maroc atlantique (Rihane, 2003, 2004 et 2005) caractérisé par une nette abondance des oiseaux.Mots-clés: régime alimentaire, chouette effraie, Lalla Mimouna , plaine du Gharb, Maroc atlantique. Study of the diet of the Barn Owl Tyto alba (Strigiforme, Tytonidae) in Lalla Mimouna region in the Gharb plain (plain of Atlantic Morocco)We present in this work the results of the analysis of the diet of the Barn owl Tyto alba in the plains of Atlantic Morocco, from several batches of diet pellets collected in 2012. These study covers two regions of the Gharb plain, one located in ananthropized forest (Sidi Boubker El Haj) and the other in the middle irrigated and intensively cultivated (field Drader Moulay Bouselhame). The study of several lots of pellets has provided 1285 prey over several zoological groups making the most of the diet of this predator. Mammals are much more represented with approximately 64% of the diet,the insects are strongly represented with more than 27% while birds and amphibians make up less than 10%. The scheme of this diet differs greatly from that of semi-arid plains of Atlantic Morocco (Rihane, 2003, 2004 and 2005) characterized by a marked abundance of birds.Keywords: diet, barn Owl, Lalla Mimouna, gharb plain, Atlantic Morocco

Impact of shorebird predation on intertidal macroinvertebrates in a key North African Atlantic wintering site: an experimental approach

Shorebirds, as migratory aquatic birds and top predators in intertidal  ecosystems, can be affected by global environmental changes and  escalations in local impacts on coastal lagoons and estuarine trophic networks. Many shorebirds winter in North African Atlantic coastal sites, most likely because these locations provide constant and reliable food supplies with less energy costs in comparison with the wintering sites of northern Europe. Although more information is available for other important  southern coastal sites (e.g. Saharan Atlantic coastal desert and Guinean mangroves coast), very little information is available for the North African Atlantic coast. Here, we focus on the impact of shorebird predation on benthic macroinvertebrates in a major wintering site in this area—Sidi Moussa coastal lagoon, Morocco—using an exclosure experiment. For most of the macroinvertebrate species there was no significant effect of the exclusion of shorebird predation. Overall, our results do not show evidence that predation by shorebirds influenced the overall standing biomass of the benthic community. This may indicate that the benthic productivity is high enough to provide constant and reliable food supplies for non-breeding shorebirds.Keywords: biomass, carrying capacity, benthic  macroinvertebrates, exclosure experiment, migration, predator–prey  interactions, Sidi Moussa lagoon, waterbird

Imputation of incomplete large‐scale monitoring count data via penalized estimation

In biodiversity monitoring, large datasets are becoming more and more widely available and are increasingly used globally to estimate species trends and conservation status. These large-scale datasets challenge existing statistical analysis methods, many of which are not adapted to their size, incompleteness and heterogeneity. The development of scalable methods to impute missing data in incomplete large-scale monitoring datasets is crucial to balance sampling in time or space and thus better inform conservation policies. We developed a new method based on penalized Poisson models to impute and analyse incomplete monitoring data in a large-scale framework. The method allows parameterization of (a) space and time factors, (b) the main effects of predictor covariates, as well as (c) space–time interactions. It also benefits from robust statistical and computational capability in large-scale settings. The method was tested extensively on both simulated and real-life waterbird data, with the findings revealing that it outperforms six existing methods in terms of missing data imputation errors. Applying the method to 16 waterbird species, we estimated their long-term trends for the first time at the entire North African scale, a region where monitoring data suffer from many gaps in space and time series. This new approach opens promising perspectives to increase the accuracy of species-abundance trend estimations. We made it freely available in the r package ‘lori’ (https://CRAN.R-project.org/package=lori) and recommend its use for large-scale count data, particularly in citizen science monitoring programmes