The species-rich calcareous grassland communities in Europe are gradually disappearing due to lack of management such as grazing or cultivation, resulting in decalcification and reduction of gaps in the vegetation. In this study, experimental soil perturbation (deep and shallow) was performed in degenerated sandy grassland in plots with a size of 8 9 8 m, using a randomised block design. The hypothesis that soil perturbation that inverts the soil layers decreases nutrient availability, creates vegetation gaps and thereby selects for desirable species was tested through comparisons with untreated controls as well as with nearby target habitats. The deep perturbation was designed to bring CaCO 3 up to the surface, whereas the shallow perturbation tested the effect of disturbance alone. The effects of soil perturbation on soil chemistry, vegetation and beetle communities were analysed for the 2 years following the treatments. Increased pH and calcium concentration, and decreased nitrogen and phosphorus availability, showed that deep perturbation was successful in restoring the soil chemistry to levels similar to those of the target habitat. Perturbated plots were rapidly colonised by the acid tolerant grass Corynephorus canescens, but the slow colonisation of the threatened calcicole species Koeleria glauca was an indication that the vegetation could be evolving towards the target vegetation. Six red-listed beetle species associated with open, dry grasslands were found, out of which four were found only in perturbated plots, although this could not be statistically tested. In conclusion, it may take many years or even decades for the establishment of desirable flora, and seeding could therefore be a suitable method of increasing the rate of succession.
DNA barcoding (molecular characterisation) is a useful tool for describing the taxonomy and systematics of organisms. Over 250 species of avian haemosporidian parasites have been described using morphological characters, yet molecular techniques based on polymerase chain reaction (PCR) suggest this diversity is underestimated. Moreover, molecular techniques are particularly useful for the detection of chronic infections and tissue stages of these parasites. Species delimitation is problematic among haemosporidians, and many questions about the mechanisms and patterns of speciation, host specificity and pathogenicity are still unresolved. Accumulation of additional genetic and morphological information is needed to approach these questions. Here, we combine microscopic examination with PCR-based methods to develop molecular characterisation of Haemoproteus (Parahaemoproteus) manwelli Bennett, 1978 and Haemoproteus (Parahaemoproteus) gavrilovi Valkiūnas & Iezhova, 1990, both of which parasitise the bee-eater Merops apiaster L. We also describe a new species, Haemoproteus (Parahaemoproteus) palloris n. sp., from the blood of the willow warbler Phylloscopus trochilus (L.). We performed phylogenetic analyses with a set of mitochondrial cytochrome b (cyt b) gene lineages, which have been linked to parasite morphospecies and are available in the MalAvi database. Our findings show that morphological characters, which have been traditionally used in the description of haemosporidians, exhibit phylogenetic congruence. This study contributes to a better understanding of avian haemosporidian diversity and provides new molecular markers (cyt b and apicoplast gene sequences) for the diagnostics of inadequately investigated haemosporidian infections.
Cue-conflict experiments were performed to study the compass calibration of one predominantly diurnal migrant, the dunnock (Prunella modularis), and two species of nocturnal passerine migrants, the sedge warbler (Acrocephalus schoenobaenus), and the European robin (Erithacus rubecula) during autumn migration in South Sweden. The birds' orientation was recorded in circular cages under natural clear and simulated overcast skies in the local geomagnetic field, and thereafter the birds were exposed to a cue-conflict situation where the horizontal component of the magnetic field (mN) was shifted +90° or −90° at two occasions, one session starting shortly after sunrise and the other ca. 90 min before sunset and lasting for 60 min. The patterns of the degree and angle of skylight polarization were measured by full-sky imaging polarimetry during the cue-conflict exposures and orientation tests. All species showed orientation both under clear and overcast skies that correlated with the expected migratory orientation towards southwest to south. For the European robin the orientation under clear skies was significantly different from that recorded under overcast skies, showing a tendency that the orientation under clear skies was influenced by the position of the Sun at sunset resulting in more westerly orientation. This sun attraction was not observed for the sedge warbler and the dunnock, both orientating south. All species showed similar orientation after the cue-conflict as compared to the preferred orientation recorded before the cue-conflict, with the clearest results in the European robin and thus, the results did not support recalibration of the celestial nor the magnetic compasses as a result of the cue-conflict exposure.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.