Fourteen polymorphic microsatellite loci characterized in the house sparrow Passer domesticus (Passeridae,Aves)

We characterized 14 polymorphic microsatellite loci in the house sparrow Passer domesticus. Four loci were isolated from house sparrow genomic libraries and 10 loci were identified by testing 100 loci that had been originally isolated in other passerine species. Loci were characterized in 37–54 unrelated sparrows from British and Norwegian populations. Each locus displayed between two and 31 alleles, with the observed heterozygosity ranging between 0.30 and 0.91.     

Prediction of the distribution of Arctic-nesting pink-footed geese under a warmer climate scenario

Global climate change is expected to shift species ranges polewards, with a risk of range contractions and population declines of especially high-Arctic species. We built species distribution models for Svalbard-nesting pink-footed geese to relate their occurrence to environmental and climatic variables, and used the models to predict their distribution under a warmer climate scenario. The most parsimonious model included mean May temperature, the number of frost-free months and the proportion of moist and wet moss-dominated vegetation in the area. The two climate variables are indicators for whether geese can physiologically fulfil the breeding cycle or not and the moss vegetation is an indicator of suitable feeding conditions. Projections of the distribution to warmer climate scenarios propose a large north- and eastward expansion of the potential breeding range on Svalbard even at modest temperature increases (1 and 2 °C increase in summer temperature, respectively). Contrary to recent suggestions regarding future distributions of Arctic wildlife, we predict that warming may lead to a further growth in population size of, at least some, Arctic breeding geese.     

Geographically congruent large‐scale patterns of plastid haplotype variation in the European herbs Silene dioica and S. latifolia (Caryophyllaceae)

The closely related dioecious herbs Silene latifolia and Silene dioica are widespread and predominantly sympatric in Europe. The species are interfertile, but morphologically and ecologically distinct. A study of large‐scale patterns of plastid DNA (polymerase chain reaction–restriction fragment length polymorphism) haplotypes in a sample of 198 populations from most of the European ranges of both species revealed extensive interspecific haplotype sharing. Four of the 28 detected haplotypes were frequent (found in > 40 populations) and widespread. Three of these frequent haplotypes occurred in both species and the geographic distribution of each haplotype was broadly congruent in both species. Each of these three, shared and widespread haplotypes is likely to have colonized central and/or northern Europe after the last glaciation from one or more of refugial areas in southern Europe. Interspecific hybridization and plastid introgression within refugial regions and/or during the early stages of postglacial expansion is the most plausible explanation for the broadly similar distribution patterns of the shared, frequent chloroplast haplotypes in the two species. The fourth frequent, widespread haplotype was absent from S. latifolia and almost entirely restricted to Nordic S. dioica. It is most likely that this haplotype spread into the Nordic countries from a central or northern European source or from a refugial area in Russia. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161 , 153–170.     

Competitive exclusion along climate gradients: energy efficiency influences the distribution of two salmonid fishes

We tested the importance of thermal adaptations and energy efficiency in relation to the geographical distribution of two competing freshwater salmonid fish species. Presence–absence data for Arctic char and brown trout were obtained from 1502 Norwegian lakes embracing both temperature and productivity gradients. The distributions were contrasted with laboratory‐derived temperature scaling models for food consumption, growth and energy efficiency. Thermal performances of the two species were almost identical. However, Arctic char exhibited double the growth efficiency (per unit of food) and appear to have out‐competed brown trout from cold, low‐productivity lakes, perhaps by scramble competition. Brown trout, for which previous reports have shown to be aggressive and dominant, have likely excluded the more energy‐efficient Arctic char from relatively warm, productive lakes, perhaps by contest competition. Competitive interaction changing in outcome with lake productivity, rather than thermal performance, is likely a major determinant of the range distribution of the two species. Our study highlights the need for more focus on choice of relevant ecophysiological traits in ecological climate impact studies and species distribution modelling.     

Characterization of flowering time diversity in Miscanthus species

Miscanthus sinensis, M. sacchariflorus and their hybrids have been identified as leading candidates for the provision of bioenergy production across several continents. Flowering time is an important trait affecting biomass yield as well as certain quality attributes, such as moisture content at harvest. The aim of this study was to ascertain the level of diversity available to breeders and potential for hybridisation of different accessions in a large collection of Miscanthus. We also sought to determine trends in flowering time within and between species with respect to environment and origin of collection data (where known), whether flowering order was maintained across years, and the extent of uniformity of flowering in different genotypes. Flowering time was observed weekly in 244 genotypes of two Miscanthus species (M. sinensis, M. sacchariflorus) and inter‐specific hybrids including M. x giganteus over 3 years and using 4 clonal replicates of each genotype on a trial planted near Aberystwyth (Wales, UK). Differences in flowering time across the entire collection ranged from 160 to 334 days (June to November) and photoperiods between 7.8 and 16.6 h, with associated accumulated temperatures of 161 to 865^oCd. More than two thirds of the collection flowered by the end of each growing season. M. sinensis individuals were the earliest genotypes to flower and showed the greatest diversity with respect to the onset of flowering. Flowering times in genotypes of known origin in Asia could be partially explained by growing season rain fall, degree days and mean temperature. Uniform flowering was identified in some genotypes. This will be important for the development of genetically diverse seed‐based crops. Rank order of flowering was shown to be consistent across Western Europe, thereby justifying single site trials as the basis of germplasm characterisation for wider geographical deployment.     

Furrows and firmgrounds: evidence for predation and implications for Palaeozoic substrate evolution in Rusophycus burrows from the Silurian of New York

Tarhan, L.G., Jensen, S. & Droser, M.L. 2011: Furrows and firmgrounds: evidence for predation and implications for Palaeozoic substrate evolution in Rusophycus burrows from the Silurian of New York. Lethaia, Vol. 45, pp. 329–341. The Silurian Herkimer Formation of east‐central New York contains abundant, exceptionally preserved composite Rusophycus‐Teichichnus burrows. We suggest that the most likely interpretation of these composite trace fossils is as structures formed by trilobites entering the sediment in search of prey. Parallel alignment of the paired traces, asymmetrical configuration of the Teichichnus along the longitudinal axis of the associated Rusophycus, depth correlation and deformation of the Teichichnus all suggest that this relationship was predatory. In addition, sectioned material indicates that these Rusophycus may have been open at the sediment‐water interface, while the crisp preservation of both Rusophycus and Teichichnus, along with the preservation of such delicate morphological details as scratch marks, suggests that the sediment must have been relatively firm at the time the traces were formed. The formation and preservation of Rusophycus in cohesive sediments located very close to the sediment‐water interface hold important implications for the manner in which we consider Palaeozoic substrates and their temporal and spatial evolution. Moreover, these findings demonstrate that the morphology and taphonomy of ichnological associations may, in the context of sedimentological relationships, prove a powerful proxy for tracking substrate conditions through both space and time. □firmgrounds, New York, predation, Rusophycus, substrate, taphonomy.     

Quantifying the activity levels and behavioural responses of butterfly species to habitat boundaries

1. The ability of species' to undergo climate‐driven range shifts across fragmented landscapes depends on their dispersal ability as well as the structure of the landscape. For species' range shifts to occur, individuals must first leave suitable habitat to seek new habitat; this is likely to depend on the rate of movement of individuals within habitat and the likelihood that a boundary is crossed, once it is encountered. For three species of butterfly with contrasting histories of recent range expansion, we examined the propensity of individuals to move within a habitat and their responses to habitat boundaries. 2. We quantified the extent to which Plebejus argus (Linnaeus) (a declining habitat specialist), Aricia agestis (Schiffermuller) (an expanding generalist) and Polymmatus icarus (Rottemburg) (a geographically ubiquitous generalist) crossed habitat boundaries into unsuitable habitat and moved within suitable habitat. The observed movement was then related to individual and environmental conditions. 3. Species differed in their activity levels in accordance within their recent distribution patterns (P. icarus > A. agestis > P. argus). Our results for P. argus suggest that movement may be motivated by nectar‐seeking, and that males generally move more than females. All three species tended to avoid crossing habitat boundaries; however the proportion of individuals crossing habitat boundaries did not differ significantly among species. 4. We conclude that levels of activity within a habitat, which will affect the frequency with which individuals encounter habitat boundaries, rather than behavioural responses to the boundaries, may be important drivers of distribution change.