Comparison of reptile sampling in Iran with pitfall versus double-ended funnel traps

In north Khorasan province, Iran, we compared the effectiveness of two types of traps for collecting reptiles: funnel traps and pitfall traps. Three stations were monitored over three 10-day periods and in total 544 individuals (including 200 recaptures) belonging to 5 species and 4 families of lizards (Lacertidae) were collected. Funnel traps with 280 captures were more efficient than pitfall traps with 264 captures, but the differences between the two traps are not significant. Three species were captured most often in the three different stations respectively: station 1, Bunopus crassicauda (22% relative frequency); station 2, Eremias fasciata (29% relative frequency); and station 3, Trapelus agilis (32% relative frequency). Shannon species richness indices were higher for pitfall than funnel traps (i.e., 1.45 vs. 1.40), but the difference was not significant. Pitfall traps were better for capturing species that search widely for food, while the funnel traps preferentially captured species that climb plants, such as Trapelus agilis. We recommend using both types of trap to capture the various types of species in any one region.     

Native range variation in Capsella bursa-pastoris (Brassicaceae) along a 2500 km latitudinal transect

Capsella bursa-pastoris (L.) Medik. is a self compatible tetraploid annual species which has successfully spread to most continents and is mostly confined to man-made habitats. The colonising success may be associated with fine-scaled ecotypic differentiation, and regional adaptation. Seeds of 377 individuals from 40 provenances were collected over a distance of more than 2500 km from the Kola Peninsula in the north to the Caspian Sea in the south in Russia and from northern to southern Scandinavia. 3558 progenies were investigated in common garden field experiments in order to distinguish between phenotypic variability and genetic variation of quantitative life-history traits (onset of flowering, rosette diameter, leaf type, plant height, and branching and fruit characters). Genetic diversity and population structure was examined with isozyme analysis. Along both transects, Capsella showed clinal differentiation in phenotypic traits: e.g., the most northern and most southern provenances flowered earlier than the provenances from in between. A highly significant quadratic correlation exists between morphological traits and the degree of latitude. Distribution of leaf types showed no geographical pattern, unlike that observed for other regions. Allozyme variation follows a pattern of isolation by distance.     

Recent evolution of sedimentary heavy metals in a coastal lagoon contaminated by industrial wastewaters (Pialassa Baiona,Ravenna, Italy)

From 2000 to 2002, sediment contamination by Cd, Cu, Hg, Pb and Zn was analysed in the Pialassa Baiona salt marsh, which receives petrochemical wastewaters from the industrial district of Ravenna (Italy). The recent contamination levels were compared with data of previous studies carried out in 1982, in order to assess whether environmental policies and remedial measures reduced sediment pollution. Sedimentary profiles of Cu and Pb were homogeneous along the uppermost 0–10 cm horizon, which corresponded to the sedimentation in the last 30 years. Concentrations of Zn attained a peak (up to 800 mg kg⁻¹ dry weight) in the 0–4 cm sediment horizon, which was assumed to correspond to the last 10–15 years. A wide-spread contamination by Hg was detected in the salt marsh as well as in the main channel with peaks up to 20–40 mg kg⁻¹ dry weight. Nonetheless, recent sediments resulted less contaminated, since Hg discharge from industrial plants ceased about 20 years ago. Contamination levels by Hg values were two orders of magnitude higher than the international sediment quality standards. Cadmium, which was analysed for the first time in 2000–2002, attained a peak in the surface layers (1–2.5 mg kg⁻¹ d.w.), with a progressive decline along the sediment column. Through comparison with pre-industrial values detected in the deeper sediment horizons (before 1920), Hg showed the highest enrichment factor, up to 300 times. Cd and Zn concentrations in recent sediments were from 2 to 10 times higher than background values. In terms of possible adverse effects, Hg posed the highest risk, and Cd and Zn were frequently above the recommended thresholds.     

Laminin A, B1, and B2 Chain Gene Expression in Transected and Regenerating Nerves: Regulation by Axonal Signals

Abstract: Laminin A, B1, and B2 chain mRNA levels in degenerating and regenerating mouse sciatic nerves were examined using northern blot analysis. In normal intact nerves, B1 and B2 mRNA steady-state levels were high, but when the nerves were crushed, the steady-state levels of B1 and B2 mRNA per milligram wet tissue weight of the distal segments of the nerves increased five- to eightfold over that of control levels as the total RNA and β-actin mRNA levels increased, suggesting that these increases were the consequence of Schwann cell proliferation after axotomy. When the steady-state levels of B1 and B2 mRNA were normalized as the ratio to total RNA or β-actin mRNA levels, however, they drastically decreased to about 20% of the normal nerve levels in the nerve segments distal to both the crush and transaction sites 1 day after injury. In the crushed nerves, B1 and B2 mRNA levels gradually increased as the regenerating nerves arrived at the distal segments and reestablished normal axon–Schwann cell contact, and then returned to normal levels on the 21 st day. In the transected nerves, where Schwann cells continued to be disconnected from axons, both B1 and B2 mRNA levels remained low. Cultured Schwann cells expressed detectable levels of B1 and B2 chain mRNA which significantly increased when the cells were cocultured with sensory neurons. However, mRNA for A chain was not detectable in the normal, axotomized nerves or in cultured Schwann cells. These data indicate that Schwann cells express laminin B1 and B2 chain mRNA that are up-regulated by axonal or neuronal contact, but they do not express A chain mRNA.     

Carriage of Neisseria meningitidis and Neisseria lactamica in northern Greece

In response to an increase in the number of cases of invasive meningococcal disease (IMD) in northern regions of Greece, a survey was carried out to determine if there was an increase in carriage of Neisseria meningitidis, particularly in areas where there have been increases in immigrant populations from neighbouring countries. The second objective was to determine if there was an increase in the serogroup C:2a:P1.5,2 a phenotype associated with recent outbreaks or changes in antibiotic sensitivities. As carriage of Neisseria lactamica is associated with development of natural immunity to IMD, the third objective was to determine the carriage rate of N. lactamica in this population. Among 3167 individuals tested, meningococci were isolated from 334 (10.5%). Compared with our previous studies, the proportion of meningococcal carriers was significantly increased among children in secondary education (11.3%) (chi2=9.67, P<0.005) and military recruits (37.4%) (chi2=21.11, P<0.000). Only 5/334 (1.5%) isolates expressed the phenotype associated with the increase in IMD in Greece. N. lactamica was isolated from 146/3167 (4.6%) participants. It was isolated from 71/987 (7.2%) children attending primary or nursery schools; however, the highest proportion of carriers (11.3%) was found in the boarding school for young Albanian men. In the 21-59-year age range, the majority of N. lactamica isolates (22/25, 88%) were from women, probably due to closer or more prolonged contact with children in the primary school age range. Smoking was significantly associated with isolation of meningococci from men but not from women. Penicillin-insensitive strains (25/334, 7.5%) were identified in all four regions examined; the majority (14/25, 56%) were obtained from military personnel. We conclude that there was a higher proportion of carriers in the population of northern Greece; however, the increase in carriage rate was not associated with the influx of immigrants from neighbouring countries, and there was not a higher incidence of the C:2a:P1.5,2 strain responsible for increased disease activity in Greece in either the immigrant or local populations.     

Effects of the winter beechmast crop on bird occurrence in British gardens

Capsule Woodland birds were significantly less likely to occur in gardens in years of high beechmast crop.

Aim To test the hypothesis that woodland species that feed on beechmast will have significantly lower occurrence rates at garden feeders in mast years.

Methods Weekly winter occurrence rates at garden feeders between 1970/71 and 1999/2000 for 40 species were analysed in relation to annual beechmast abundance, classified into low, medium and high years. A repeated-measures logistic regression model was used to assess whether beechmast abundance explained further significant variation additional to underlying seasonal and annual trends.

Results Seven species that commonly feed on beechmast showed significantly lower occurrence in gardens in years of highest beechmast abundance: Great Spotted Woodpecker Dendrocopos major, Woodpigeon Columba palumbus, Great Tit Parus major, Coal Tit Periparus ater, Nuthatch Sitta europaea, Jay Garrulus glandarius and Chaffinch Fringilla coelebs. Blackbird Turdus merula and Siskin Carduelis spinus, which showed similar significant patterns, are likely to take beechmast as elements of their diet. Pied Wagtail Motacilla alba was the only insectivorous species to show significant effects, but occurrence was lowest in years of intermediate beechmast abundance. For the latter species, this may have been due to confounding effects of temperature, but there were no such confounding effects of either temperature, or the number of bird feeders provided in gardens, for the other nine species.

Conclusion Use of artificial food sources by birds in gardens is influenced by resources in the surrounding countryside, suggesting that food provided in gardens may play a significant part in the population dynamics of these species, that population monitoring without consideration of the garden habitat may be deficient, and that volunteer-based garden bird recording may provide data that can be used as an indicator of changes in the wider countryside.     

Population genetic structure, phylogeography and spawning philopatry in walleye (Stizostedion vitreum) from mitochondrial DNA control region sequences

Mitochondrial (mt) DNA control region sequences were used to test the genetic and phylogeographic structure of walleye Stizostedion vitreum populations at different geographical scales: among spawning sites, lake basins, lakes, and putative glacial refugia in the Great Lakes region. Sequencing 199 walleye revealed nucleotide substitutions and tandemly repeated sequences that varied in copy number, as well as in sequence composition, in 1200 bp of the mtDNA control region. Variable numbers of copies of an 11-bp tandem repeat showed no geographical patterning and were not used in further analyses. Substitutions in the other areas of the control region yielded 19 haplotypes, revealing phylogeographic structure and significant differences among glacial refugia, lakes, basins and some spawning sites. Differences among spawning populations were consistent with reduced gene flow, philopatry and possible natal homing. Analysis of spawning populations showed consistency of genotypic frequencies among years and between males and females, supporting philopatry in both sexes. The unglaciated plateau in southern Ohio, USA housed a very different haplotype that diverged prior to the Missouri, Mississippi and Atlantic glacial refugia types. Haplotypes from the three refugia colonized the Great Lakes after retreat of the Wisconsin glaciers, and their present distribution reflects the geography of their prior isolation and differential colonization. Populations that became associated with spawning localities appear to have diverged further due to philopatry, resulting in fine-scale phylogeographic structuring.     

Identifying plant functional types using floristic data bases: Ecological correlates of plant range size

Abstract. In an effort to identify ‘plant functional types’, the islands floras of Great Britain and Kríti (Crete, Greece) were examined separately for ecological correlates of plant range size. Plant functional types (PFTs) were defined here as categories into which plants could be grouped on the basis of attributes that predict greater or lesser sensitivity to ecological variability. Plant range size indicates commonness of a species and was assumed to be a proxy for ‘ecological flexibility’, i.e. species of larger range sizes can better withstand environmental change and differences than species of smaller range sizes. Using evolutionary comparative methods that account for the effect of taxonomic relatedness, both floras were investigated for the effects on range size of woodiness vs. non-woodiness, trees vs. shrubs, trees vs. herbs and shrubs vs. herbs. The British flora was examined additionally for the effects of wind- vs. non-wind-pollination, self vs. animal pollination and animal vs. non-animal fruit dispersal on range size. Two analyses showed significant effects on range size: for British species, trees had larger ranges than shrubs, and wind- pollinated species had larger ranges than non-wind-pollinated species. It is suggested that the lack of a similar pattern for shrubs and trees in Kríti is because the lower water availability of Kríti imbues shrubs with an ecophysiological advantage not relevant in plants of Great Britain. That trees have larger range sizes than shrubs in Great Britain is ascribed to the greater importance of competition for light when other factors are not at issue. The greater range of wind-pollinated than non-windpollinated species in Great Britain is postulated to be because both mutualists must be capable of invading new areas. This may be termed a ‘cost of mutualism’. In terms of PFTs, the results indicate that ‘life-form’ is too broad a classification category by which to differentiate relative sensitivity to environmental variability in Great Britain, in that there were significant differences in range size of trees and shrubs, but not between either of the two categories and herbs, or between woody and non-woody plants. Although pollination type may predict relative sensitivity to variation in Great Britain, dispersal type will not. Finally, differences between Great Britain and Kríti in relative range size patterns suggests that plant functional types may be specific to a region or set of conditions.     

Direct fitness benefits explain mate preference,but not choice,for similarity in heterozygosity levels

Under sexual selection, mate preferences can evolve for traits advertising fitness benefits. Observed mating patterns (mate choice) are often assumed to represent preference, even though they result from the interaction between preference, sampling strategy and environmental factors. Correlating fitness with mate choice instead of preference will therefore lead to confounded conclusions about the role of preference in sexual selection. Here we show that direct fitness benefits underlie mate preferences for genetic characteristics in a unique experiment on wild great tits. In repeated mate preference tests, both sexes preferred mates that had similar heterozygosity levels to themselves, and not those with which they would optimise offspring heterozygosity. In a subsequent field experiment where we cross fostered offspring, foster parents with more similar heterozygosity levels had higher reproductive success, despite the absence of assortative mating patterns. These results support the idea that selection for preference persists despite constraints on mate choice.     

Phytoplankton and phosphorus in southern Georgian Bay, 1973–1982, and implications for phosphorus loading controls

The phytoplankton and nutrient status of the embayments between Penetanguishene and Waubaushene in southern Georgian Bay (Severn Sound) were examined during the ice-free periods of 1973–1982 because the area showed symptoms of excessive nutrient enrichment. Four wastewater treatment plants currently discharge to the area, another is under construction and a sixth plant has been proposed. Except for Penetang Bay, the area is well-mixed by prevailing winds but is somewhat isolated from the main part of Georgian Bay. Average phytoplankton biomasses throughout the area were 10–20× higher than values from adjacent Nottawasaga Bay where, during 1980, total phytoplankton biomass ranged between 0.15 and 0.25 mm³ · l^–1. Total phosphorus concentrations were highest in Penetang Bay, ranging between 30 and 49 µg P · l^–1 (May–September means) over the 10 year period. Phosphorus concentrations in Nottawasaga Bay averaged 4–6 µg P · l^–1 and no significant differences were detected among the sampling stations; however, phytoplankton densities at stations near urban centres and river inflows were significantly higher than at more remote offshore sites and attests to the use of phytoplankton as a sensitive measure of trophic status in Georgian Bay.Although improvement of Severn Sound water quality to a level comparable to that presently existing in Nottawasaga Bay may never be practical, steps are being taken to control high industrial phosphorus loading and to lessen bypassing of sewage treatment facilities previously hydraulically overloaded during periods of heavy runoff. These measures, along with an evaluation of other major sources of nutrients to Severn Sound, should enable a refinement of the nutrient management programme for Severn Sound and some improvement in trophic status.