An unexpected pattern of migration revealed in the Subalpine Warbler Sylvia cantillans complex by mitochondrial DNA analyses

Genetic markers are often used to trace the geographical origin of migrating birds. Such an approach has been used to attribute individuals of a given species to a given population, but it could also be applied to cryptic species, which are not fully diagnosable on the basis of their morphological appearance alone, despite often being genetically distinct. We sampled migrants of the Sylvia cantillans complex, which include cryptic taxa not readily identified on the basis of their appearance, at spring stopover sites in the central Mediterranean. We identified these individuals taxonomically using mitochondrial DNA sequence data. Molecular analyses enabled us to establish that four different taxa/clades of the Sylvia cantillans complex (two S. c. cantillans clades, S. c. albistriata and S. subalpina) migrate through the central‐western Mediterranean from Africa.     

Environmental factors affecting patterns of distribution and co‐occurrence of two competing raptor species

Habitat selection is a complex process, that is affected by several factors, including habitat characteristics, environmental conditions, and both intra‐ and interspecific interactions. We analysed habitat preferences of two top avian predators, Peregrine Falcon Falco peregrinus, a medium‐sized diurnal raptor, and Eagle Owl Bubo bubo, a large nocturnal raptor. These two species are known to compete for preferred nest‐sites, and proximity to cliffs with Eagle Owls may reduce Peregrine breeding output through predation of young Falcons. We investigated the environmental factors affecting occurrence and coexistence of the two species and the potential role of habitat suitability in favouring co‐occurrence in 3519 km² of the central pre‐Alps of Italy, where the two species breed on cliffs and sometimes co‐occur on the same cliff. Peregrines settled on long, steep and favourably orientated cliffs in woodland landscapes close to urban areas. Eagle Owls settled on topographically similar cliffs, but in lower rainfall areas compared with cliffs occupied by Peregrines and cliffs unoccupied by either species. Sites where the two species co‐occurred were characterized by more horizontally extended cliffs compared with sites of exclusive occurrence of each species. An analysis of relative habitat suitability revealed that sites where the two species co‐occurred had the highest predicted probability of occupancy for both species, suggesting that those sites should be regarded as high‐quality sites. Breeding productivity of Eagle Owls was negatively affected by the co‐occurrence of Peregrines, whereas the effect of Eagle Owl proximity on Peregrine productivity varied according to cliff suitability for the Peregrines. Habitat selection had fitness consequences for Eagle Owls because breeding productivity increased with cliff length. Environmental conditions, particularly climatic factors, could allow the widespread coexistence of these competing raptors at the landscape scale, whereas at the local scale co‐occurrence could take place only on larger cliffs. These were preferred sites for both species, presumably because breeding at such sites offsets the costs of settling close to the competitor species.     

Effect of Anaerobiosis on Rice Seedlings: Growth, Metabolic Rate, and Fate of Fermentation Products

When 3 d old aerobic rice seedlings are subjected to 48 h ofanaerobiosis a strong alcoholic fermentation system is inducedwhich operates at a constant rate during the treatment. Ethanol accumulates in seedling tissues during the first hoursof anaerobiosis to reach a limit value which is maintained thereafter.Of the total ethanol production during the anaerobic treatment,only 2% is accounted for by ethanol stored in tissues, the remaining98% is found in the growth medium. Concomitant effects of anaerobiosis on seedling growth, consumptionof endosperm reserves, and variations in the level of activityof alcohol dehydrogenase (ADH) and soluble proteins are reported.