but have declined in species richness, geographical range and abundance (2-5). Previous studies have assessed the roles played by habitat destruction and loss of flower resources (4,5), and pesticides (6) over relatively modest time scales and geographical ranges.Analyses of regions are rare (7-10) and our understanding of the effects of humanmediated actions over longer periods is limited. Here we assess the bee and flowervisiting wasp species that have gone extinct in Britain, using 494,117 records held by the Bees, Wasps and Ants Recording Society (BWARS), probably the most detailed available for a single country. We define extinct species as those that have not been recorded for at least 20 years following their last observation, despite extensive efforts by members of BWARS and other naturalists.Twenty-three bee and flower-visiting wasp species have become extinct in Britain (Table 1), including formerly widespread species. We exclude single early records that cannot be verified as representing stable breeding populations, but include one species which has recolonized Britain after an absence of six decades (see Supplementary Materials).Since the mid 19 th century the pattern of British bee and wasp extinctions has been characterized by intervals of relative stability, in which few species were lost, interspersed with times when over three species per decade went extinct ( Figure 1, Table 2). These data indicate a period of relatively sustained extinctions from the late 1920s to the late 1950s, with other isolated extinction peaks before and after this time. These features are confirmed in Figure 2, where the average gradient indicates the relative extinction rate over a period, and the period of sustained extinctions is evident as the phase of maximum gradient during the mid 20 th century.The varying rates of extinctions were quantified by applying breakpoint analysis to the cumulative record. In this analysis, a piecewise linear model is fitted to data to reveal periods of approximately constant extinction rate, separated by breakpoints where the rate changes. The analysis was iterated for up to 10 breakpoints and the Akaike Information Criterion (AIC), confirmed by coefficient of determination (multiple-R 2 ), was used to establish the best model (see Supplementary Materials). For these data, changes in AIC and muliple-R 2 level off for two models having four breakpoints (Table S2). These are very similar, sharing the latter three breakpoints, and revealing effectively identical periods of approximately uniform extinction rate for the majority of the 20 th century (Table 2).Both models must be interpreted with caution as the data for 'year last recorded' may not equate to 'year last living'. Declines in populations due to habitat changes may mean a species went unrecorded for some years prior to the actual extinction. The robustness of the breakpoints to this potential ambiguity of the probability of the 'year last living' has been assessed and, whilst there is some sensitivity in the timing of the e...

The demise of coppicing in UK ancient woodlands, combined with the planting of non-native, fast-growing conifers in the twentieth century, heightens the potential recharge value of ground flora seed banks. Soil cores from adjoining semi-natural and conifer-containing stands in four lowland ancient woods in central England were removed to establish seed bank species richness. During a fourteen-month germination trial soil from two depths yielded 6554 seedlings from 81 species, ten of which showed a strong affinity for ancient woodland conditions. Juncus effusus accounted for 80 of emergent seeds whilst 23 other species, including Lysimachia nummularia and Potentilla sterilis, were represented by only one individual. Species richness is described by a model that explains 40 of observed variance (P < 0.00001). The model has three significant variables: species richness increases as soil pH rises, and decreases with both depth and increasing time since the most recent planting/disturbance event. No difference was found in the density of seeds from species common to paired semi-natural and conifer-containing stands that were separated only by a woodland ride, suggesting prior management and environmental conditions have a greater influence on seed banks than current stand type. Sørensen similarity index values revealed poor congruence between above-ground vegetation and species in the seed bank. Taking pH measurements in conifer stands identified as younger in terms of planting/disturbance may help locate areas where greater numbers of species (including woodland specialists) are located. Caution is required, however, as these seed banks may also contain non-target, competitive species that may swamp the regeneration of woodland specialists. © 2010 Springer Science+Business Media B.V

: Global extinction and geological events have previously been linked with galactic events such as spiral arm crossings and galactic plane oscillation. The expectation that these are repeating predictable events has led to studies of periodicity in a wide set of biological, geological and climatic phenomena. Using data on carbon isotope excursions, large igneous provinces and impact craters, we identify three time zones of high geological activity which relate to the timings of the passage of the Solar System through the spiral arms. These zones are shown to include a significantly large proportion of high extinction periods. The mass extinction events at the ends of the Ordovician, Permian and Cretaceous occur in the first zone, which contains the predicted midpoints of the spiral arms. The start of the Cambrian, end of the Devonian and end of the Triassic occur in the second zone. The pattern of extinction timing in relation to spiral arm structure is supported by the positions of the superchrons and the predicted speed of the spiral arms. The passage times through an arm are simple multiples of published results on impact and fossil record periodicity and galactic plane half-periods. The total estimated passage time through four arms is 703.8 Myr. The repetition of extinction events at the same points in different spiral arm crossings suggests a common underlying galactic cause of mass extinctions, mediated through galactic effects on geological, solar and extra-solar processes. The two largest impact craters (Sudbury and Vredefort), predicted to have occurred during the early part of the first zone, extend the possible pattern to more than 2000 million years ago.

High-density regions within the spiral arms are expected to have profound effects on passing stars. Understanding of the potential effects on the Earth and our Solar System is dependent on a robust model of arm passage dynamics. Using a novel combination of data, we derive a model of the timings of the Solar System through the spiral arms and the relationship to arm tracers such as methanol masers. This reveals that asteroid/comet impacts are significantly clustered near the spiral arms and within specific locations of an average arm structure. The end-Permian and end-Cretaceous extinctions emerge as being located within a small star-formation region in two different arms. The start of the Solar System, greater than 4.5 Ga, occurs in the same region in a third arm. The model complements geo-chemical data in determining the relative importance of extra-Solar events in the diversification and extinction of life on Earth.

Cassava has been cultivated in Central and South America for about 8000 years. Following export to Africa and Asia in the 16th-19th centuries it is now established as a vital component of the diet of many of the world's poorest people. Growth and processing of the plant in Central and South America represents one of the few remaining expressions of indigenous knowledge. This article highlights the importance of traditional methods of cultivation and processing in contributing to a large number of varieties and maintenance of high genetic diversity. Increasingly, such diversity is being supplemented by international breeding programs with the possibility of genetically modified crops to combat plant diseases and natural enemies such as cassava mosaic virus. The article examines the issues surrounding the patenting of traditional knowledge of cassava. It concludes by exploring cassava cultivation as a contribution to the sustainable utilization of species-rich tropical forests. This combines the maintenance of high genetic diversity of the crop with traditional practices of indigenous people, thereby satisfying the requirements of article 8(j) of the United Nations Convention on Biological Diversity.

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Micropterix calthella L. (Micropterigidae) is a small, day-flying moth from the basal-most extant lineage of the Lepidoptera. The species name reflects its conspicuous presence on Caltha palustris L. (Ranunculaceae). However, adults also favour sedges (Carex spp., Cyperaceae), on which they gather gregariously to feed on pollen and find mates. In a UK ancient wood, the phenology of eight sedge species together with individual moth and mating pair densities were monitored from 15th April to 8th June 2009. 4841 moth sightings were recorded. Moths on Carex spikes at various developmental stages were compared with null models to test for preference patterns. Approximately 99 of individuals selected Carex spikes where dehiscing anthers were present. The sedge phenology data suggest three distinct periods of pollen production. Overlaying this with the moth data reveals moth phenology strongly linked to a suite of early and mid-season woodland sedges. Of the twenty-eight other angiosperm species (seventeen families) in flower, only Ranunculus ficaria L. (Ranunculaceae) and R. repens L. attracted moths. Adult moths kept in captivity on potted Carex flacca Schreb. for 10 days laid eggs at the plant-soil interface. When C. flacca pollen production ceased, surviving adults were moved onto freshly dehiscing anthers of potted C. pallescens L., where they survived a further 14 days. Soil-dwelling first instar larvae were observed to consume C. sylvatica Huds leaves. In a choice experiment, larvae were significantly more likely to consume C. sylvatica than Stellaria media (L.) Vill. (Caryophyllaceae) leaf material (previously noted to be favoured by larvae). Synchrony between adult moths and Carex spp., and the use of Carex by both adults and larvae, suggests sedges may be host plants for M. calthella in lowland ancient woodlands. © 2010 Springer Science+Business Media B.V