Migration flyway of the Mediterranean breeding Lesser Crested Tern Thalasseus bengalensis emigratus

© 2016 NISC (Pty) Ltd. The Lesser Crested Tern Thalasseus bengalensis emigratus breeding population in the Mediterranean is found exclusively in Libya, on the two coastal islands of Gara and Elba and one wetland on the mainland coast at Benghazi. In order to improve knowledge of the species migration to wintering quarters in West Africa, a ringing programme was conducted from 2006–2008 and 2009–2012. From a total of 1 354 nestlings ringed using metal and/or colour rings, 64 were recovered along their flyway and in their wintering range, representing 6.9% of birds ringed with both colour and metal rings. This provided the opportunity to collect information on post-natal movements (staging and wintering ranges), breeding philopatry and recruitment, in addition to a preliminary estimate of their migration journey duration. This paper indicates sighting and recovery distributions in space and time, highlighting the important areas for the species during its journey between breeding and wintering sites. The findings indicate that several areas where ringed terns stop-over during pre- and post-breeding migration journeys are not protected, causing an additional threat to their survival, as some wintering areas are also not protected. Conservation of this highly localised and threatened population needs not only to address protection at breeding sites but also at migratory stop-overs and wintering strongholds

Offspring Microbiomes Differ Across Breeding Sites in a Panmictic Species

High dispersal rates are known to homogenize host’s population genetic structure in panmictic species and to disrupt host local adaptation to the environment. Long-distance dispersal might also spread micro-organisms across large geographical areas. However, so far, to which extent selection mechanisms that shape host’s population genetics are mirrored in the population structure of the enteric microbiome remains unclear. High dispersal rates and horizontal parental transfer may homogenize bacterial communities between breeding sites (homogeneous hypothesis). Alternatively, strong selection from the local environment may differentiate bacterial communities between breeding sites (heterogeneous hypothesis). Furthermore, selection from age-specific environmental or physiological factors may differentiate the microbiome between juveniles and adults. Here, we analyzed the cloacal bacterial 16S rRNA gene of fledgling greater flamingos, Phoenicopterus roseus, across nine western Mediterranean breeding sites and four breeding seasons (n = 731) and adult birds (n = 27) from a single site. We found that fledgling cloacal microbiome, as measured by alpha diversity, beta diversity, the relative abundance of assigned sequence variants (ASVs) belonging to a phylum and genus composition within phylum, varied significantly between sampling sites and across time within site despite high adult dispersal rates. The spatio-temporal effects were stronger on individual ASV absence/presence than on ASV abundance (i.e., than on core microbiome composition). Spatial effects had a stronger effect than temporal effects, particularly on ASV abundance. Our study supports the heterogeneous hypothesis whereby local environmental conditions select and differentiate bacterial communities, thus countering the homogenizing effects of high-dispersing host species. In addition, differences in core microbiome between adult vs. fledgling samples suggests that differences in age-specific environmental and/or physiological factors result in differential selection pressure of core enteric microbiome between age classes, even within the same environment. In particular, the genus Corynebacterium, associated with both seasonal fat uptake and migration in previous studies, was much more abundant in high-dispersing fledglings than in more resident adults. To conclude, selection mechanisms that shape the host’s genetic structure cannot be extended to the genetic structure of the enteric microbiome, which has important implications regarding our understanding of both host local adaptation mechanisms and enteric microbiome population genetics

Benefits of protected areas for nonbreeding waterbirds adjusting their distributions under climate warming

Climate warming is driving changes in species distributions and community composition. Many species have a so-called climatic debt, that is, shifts in range lag behind shifts in temperature isoclines. Inside protected areas (PAs), community changes in response to climate warming can be facilitated by greater colonization rates by warm-dwelling species, but also mitigated by lowering extirpation rates of cold-dwelling species. An evaluation of the relative importance of colonization-extirpation processes is important to inform conservation strategies that aim for both climate debt reduction and species conservation. We assessed the colonization-extirpation dynamics involved in community changes in response to climate inside and outside PAs. To do so, we used 25 years of occurrence data of nonbreeding waterbirds in the western Palearctic (97 species, 7071 sites, 39 countries, 1993-2017). We used a community temperature index (CTI) framework based on species thermal affinities to investigate species turnover induced by temperature increase. We determined whether thermal community adjustment was associated with colonization by warm-dwelling species or extirpation of cold-dwelling species by modeling change in standard deviation of the CTI (CTISD). Using linear mixed-effects models, we investigated whether communities in PAs had lower climatic debt and different patterns of community change than communities outside PAs. For CTI and CTISD combined, communities inside PAs had more species, higher colonization, lower extirpation, and lower climatic debt (16%) than communities outside PAs. Thus, our results suggest that PAs facilitate 2 independent processes that shape community dynamics and maintain biodiversity. The community adjustment was, however, not sufficiently fast to keep pace with the large temperature increases in the central and northeastern western Palearctic. Our results underline the potential of combining CTI and CTISD metrics to improve understanding of the colonization-extirpation patterns driven by climate warming.Peer reviewe

Positive impacts of important bird and biodiversity areas on wintering waterbirds under changing temperatures throughout Europe and North Africa

Migratory waterbirds require an effectively conserved cohesive network of wetland areas throughout their range and life-cycle. Under rapid climate change, protected area (PA) networks need to be able to accommodate climate-driven range shifts in wildlife if they are to continue to be effective in the future. Thus, we investigated geographical variation in the relationship between local temperature anomaly and the abundance of 61 waterbird species during the wintering season across Europe and North Africa during 1990-2015. We also compared the spatio-temporal effects on abundance of sites designated as PAs, Important Bird and Biodiversity Areas (IBAs), both, or neither designation (Unlisted). Waterbird abundance was positively correlated with temperature anomaly, with this pattern being strongest towards north and east Europe. Waterbird abundance was higher inside IBAs, whether they were legally protected or not. Trends in waterbird abundance were also consistently more positive inside both protected and unprotected IBAs across the whole study region, and were positive in Unlisted wetlands in southwestern Europe and North Africa. These results suggest that IBAs are important sites for wintering waterbirds, but also that populations are shifting to unprotected wetlands (some of which are IBAs). Such IBAs may therefore represent robust candidate sites to expand the network of legally protected wetlands under climate change in north-eastern Europe. These results underscore the need for monitoring to understand how the effectiveness of site networks is changing under climate change.Peer reviewe

Waterbirds Abstracts

Click on the link to view the abstracts.Ostrich 2007, 78(2): 505–51

Contribution au suivi de la population nicheuse du faucon crecerellette (Falco naumanni) à l'Aqueduc de Zaghouan (Tunisie)

Le faucon crécerellette (Falco naumanni) est une espèce globalement menacée. Nous avons étudié la dynamique de la population de Zaghouan (Tunisie). Nos résultats suggèrent que le nombre des couples nicheuses à l'Aqueduc diminue significativement d'une année à une autre. Ce résultat serait du à la destruction ou la modification des habitats du fait des travaux de restauration de l'Aqueduc. La protection et la restauration des habitats et des sites de reproduction en particulier ainsi que l'aménagement des sites de nidification constituent les principales mesures proposés pour la conservation de l'espèce en Tunisie.The Lesser Kestrel (Falco naumanni) is a globally threatened species.We studied the population dynamics of nesting Lesser Kestrels at the aqueduct of Zaghouan (Tunisia). Our results suggest that the number of nesting pairs at this site has decreased significantly from year to year. This is primarily due to destruction or modification of nest sites during restoration of the aqueduct. The protection and the restoration of their habitat, especially of breeding sites, as well as the installation of additional nesting sites, constitute the principal conservation measures proposed for this species in Tunisia. Ostrich 2007, 78(2): 401–40

The ‘Eurasian' Spoonbill (Platalea leucorodia) in Africa

The ‘Eurasian' Spoonbill (Platalea leucorodia) nests in discrete areas across the western Palaearctic and is considered to be threatened. Western breeding populations winter along the Atlantic seaboard of Mauritania and Senegal, where they mingle with the Mauritanian subspecies P. l. balsaci. Their movements have been studied through colour ringing, which has shown that they spend their early years in Africa. Observations of Dutch breeding birds in the Mediterranean are scarce. The central European breeding population nests mainly in the Danube Basin. Recoveries of metal rings show that, while some winter in the Inner Niger Delta, most stay in the tidal Mediterranean areas of southern Tunisia and Libya, thus avoiding a long trans-Saharan journey. New colour-marking programmes in Italian and Greek breeding colonies have provided more information, but as yet there is no proof that young birds summer in the area. Some central European Spoonbills move through the Nile Delta and along the Nile to winter in southern Egypt and Sudan. Breeding Spoonbills of eastern Europe and western Asia also winter in southern Egypt and Sudan, while some winter as far east as Oman; as yet there are few ringing recoveries, but a colour-ringing programme in the Danube Delta begun in 2003 has already yielded recoveries in Spain and Oman. There is another African-breeding subspecies P. l. archeri in the Red Sea. We need to establish the importance of African wetlands for Spoonbills, concentrating on colour-ringed individuals, surveys in Libya, Egypt and Sudan, a search for summering immatures, and an investigation of why birds from the same breeding colonies take such different migration routes. La spatule blanche Platalea leucorodia (dite «eurasiatique» en langue anglaise!), espèce considérée comme étant menacée d'extinction, niche dans des zones discontinues du Paléarctique occidental. Les populations occidentales hivernent le long des côtes atlantiques de la Mauritanie et du Sénégal, où elles retrouvent la sous-espèce mauritanienne P. l. balsaci. Leurs migrations ont été étudiées grâce à l'utilisation de bagues en couleur, qui ont montré que les jeunes spatules passent leurs premières années en Afrique; les observations en Méditerranée d'oiseaux d'origine hollandaise sont rares. La population nicheuse de l'Europe centrale se reproduit surtout dans le bassin du Danube. Des reprises de bagues métalliques montrent que, si certains oiseaux hivernent dans le Delta Intérieur du Niger, la plupart restent en hiver dans les zones côtières, soumises à la marée, de la Tunisie méridionale et de la Libye, et évitent ainsi la longue traversée du Sahara. De nouveaux programmes de baguage en Italie et en Grèce, à l'usage de bagues de couleur, ont fourni des informations supplémentaires, mais jusqu'à présent la preuve de séjours estivaux dans ces zones par les immatures fait défaut. Certaines spatules venant d'Europe centrale traversent le delta du Nil pour hiverner dans le sud de l'Egypte et au Soudan. Les spatules nicheuses de l'Europe orientale et de l'ouest de l'Asie hivernent également dans le sud de l'Egypte et au Soudan, et certains vont jusqu'en Oman; jusqu'à présent, les reprises de baguage sont rares, mais un programme de baguage, entamé en 2003 dans le delta du Danube, a donné lieu à des reprises en Espagne et en Oman. Une deuxième sous-espèce africaine P. l. archeri, niche dans la Mer Rouge. Nous devons confirmer l'importance des zones humides africaines pour la spatule blanche, en utilisant des bagues de couleur, en effectuant des prospections en Libye, en Egypte et au Soudan, en recherchant les immatures estivants et en approfondissant la question de pourquoi les individus d'une même colonie suivent des chemins de migration tellement variables. Ostrich 2007, 78(2): 495–50

Survey of waterbirds wintering in Tunisia, January 2003

During a joint international expedition, there have been recorded between 18-31 January 2003 a total number of 83,653 water birds(belonging to 76 species) in 58 wetlands of Tunisia