Occurrence characteristics of mesospheric gravity waves at 51 °N

Observations of the OH(8-3) band rotational temperature have been carried out from Calgary (51 °N, 114 °W), Canada, from 1988 to 1990. The measurements have been taken in orthogonal scanning mode and the data set has been analyzed to study salient features of gravity waves in the mesospheric region from this mid-latitude station. Rotational temperature data from 36 nights showed distinct gravity wave activity during this period. The gravity wave characteristics studied include the dominant period, horizontal structure speed, implied horizontal wavelength and horizontal component of direction of propagation. The preferred direction in the horizontal wave propagation at Calgary is towards the north-west. A comparison of the observed horizontal propagation directions with the permitted directions, using model wind profiles for Calgary, shows good agreement. This indicates that the upward flow of wave energy could be modified by the background wind

Conservation status of the world's skinks (Scincidae): Taxonomic and geographic patterns in extinction risk

Our knowledge of the conservation status of reptiles, the most diverse class of terrestrial vertebrates, has improved dramatically over the past decade, but still lags behind that of the other tetrapod groups. Here, we conduct the first comprehensive evaluation (~92% of the world's ~1714 described species) of the conservation status of skinks (Scincidae), a speciose reptile family with a worldwide distribution. Using International Union for Conservation of Nature (IUCN) criteria, we report that ~20% of species are threatened with extinction, and nine species are Extinct or Extinct in the Wild. The highest levels of threat are evident in Madagascar and the Neotropics, and in the subfamilies Mabuyinae, Eugongylinae and Scincinae. The vast majority of threatened skink species were listed based primarily on their small geographic ranges (Criterion B, 83%; Criterion D2, 13%). Although the population trend of 42% of species was stable, 14% have declining populations. The key threats to skinks are habitat loss due to agriculture, invasive species, and biological resource use (e.g., hunting, timber harvesting). The distributions of 61% of species do not overlap with protected areas. Despite our improved knowledge of the conservation status of the world's skinks, 8% of species remain to be assessed, and 14% are listed as Data Deficient. The conservation status of almost a quarter of the world's skink species thus remains unknown. We use our updated knowledge of the conservation status of the group to develop and outline the priorities for the conservation assessment and management of the world's skink species