Meredith Williams

Mapping land cover change in a reindeer herding area of the Russian Arctic using Landsat TM and ETM+ imagery and indigenous knowledge

Much of Russia north of the treeline is grazed by reindeer, and this grazing has materially altered the vegetation cover in many places. Monitoring vegetation change in these remote but ecologically sensitive regions is an important task for which satellite remote sensing is well suited. Further difficulties are imposed by the highly dynamic nature of arctic phenology, and by the difficulty of obtaining accurate official data on land cover in arctic Russia even where such data exist. We have approached the problem in a novel fashion by combining a conventional multispectral analysis of satellite imagery with data on current and historical land use gathered by the techniques of social anthropology, using a study site in the Nenets Autonomous Okrug (NAO). A Landsat-7 ETM+ image from the year 2000 was used to generate a current land cover classification. A Landsat-5 TM image was used to generate a land-cover classification for 1988, taking due account of phenological differences and between the two dates. A cautious comparison of these two classifications, again taking account of possible effects of phenological differences, shows that much of the study area has already undergone a notable transformation to grass-dominated tundra, almost certainly as a result of heavy grazing by reindeer. The grazing pattern is quite heterogeneous, and may have reached unsustainable levels in some areas. Finally, we suggest that this situation is unlikely to be unique to our study area and may well be widespread throughout the Eurasian tundra zone, particularly in the west.

Monitoring changes in land cover induced by atmospheric pollution in the Kola Peninsula, Russia, using Landsat-MSS data

Abstract We present the results of hybrid unsupervised-supervised classification of a series of Landsat-MSS images, spanning the period from 1978 to 1992, to study the impact of SO2 emissions from the nickel smelter at Monchegorsk (67 55 N, 32 50 E) in the Kola Peninsula, Russia, on adjacent boreal forest and upland (lichen-dominated) tundra vegetation. Ground truth data were collected from a 2500 km2 area during airborne and surface field campaigns in 1994 and 1995, and used to classify the 1992 image into 56 different surface types, including a characterisation of the level of vegetation damage. The pre-1992 images could not be classified by transferring the spectral signatures from the 1992 image, mainly as a result of phenological differences. Instead, they were classified using spatial context and a set of observationally-derived botanical rules governing the types of allowable land-cover change. A comparison of the classified images was performed by further combining the land-cover classes into grou...

A new cycle of jokulhlaups at Russell Glacier, Kangerlussuaq, West Greenland

Jokulhlaups in 2007 and 2008 from an ice-dammed lake at the northern margin of Russell Glacier, West Greenland, marked the onset of a renewed jokulhlaup cycle after 20 years of stability. We present a record of successive ice-dammed lake drainage events and associated ice-margin dynamics spanning 25 years. Robust calculations of lake volumes and peak discharges are made, based on intensive field surveys and utilizing high-spatial-resolution orthophotographs of the lake basin and ice margin. These data enable identification of controls on the behaviour of the ice-dammed lake and provide the first field-based examination of controls on jokulhlaup magnitude and frequency for this system. We find that Russell Glacier jokulhlaups have a much higher peak discharge than predicted by the Clague-Mathews relationship, which we attribute to an unusually short englacial/subglacial routeway and the presence of a thin ice dam that permits incomplete sealing of jokulhlaup conduits between lake drainage events. Additionally, we demonstrate that the passage of jokulhlaups through an interlinked system of proglacial bedrock basins produces significant attenuation of peak discharge downstream. We highlight that improved understanding of jokulhlaup dynamics requires accurate information about ice-dammed lake volume and ice-proximal jokulhlaup discharge.

Surge-type glaciers in the Russian High Arctic identified from digital satellite imagery

Landsat digital imagery was used to search the island archipelagos of Franz Josef Land, Severnaya Zemlya and Novaya Zemlya, Russian High Arctic, for the presence of looped moraines characteristic of past glacier surges. The imagery provides almost complete summer-time coverage of the 60000 km 2 of ice in these islands. Very few surge-type glaciers are identified: none in Franz Josef Land, three in Novaya Zemlya and two on Severnaya Zemlya. This contrasts greatly with Svalbard (ice-covered area 36 600 km 2 ), to the west, where 36% of glaciers and ice-cap drainage basins are inferred to surge. The strong climatic gradient across the Eurasian High Arctic, with decreasing temperature and moisture eastward, may provide a gross control on this pattern through colder glacier thermal structure, limiting basal drainage on the thinner ice masses in particular.

Historical fluctuations of the Matusevich Ice Shelf, Severnaya Zemlya, Russian High Arctic

Dramatic retreat of ice shelves in Antarctica in recent years, linked to climatic warming, is well documented. In contrast, the ice shelves of the Russian Arctic remain largely unstudied. A time-series analysis of the largest ice shelf in the Russian High Arctic, the Matusevich Ice Shelf, Severnaya Zemlya, was undertaken for the period 1931 to 1994 using georeferenced Landsat satellite imagery and published maps. The positions of three major ice margins in 1931, 1955, 1962, 1973, 1985, 1988, and 1994 are compared. The floating margin of the ice shelf underwent at least two cycles of retreat followed by periods of advance between 1931 and 1994. These periodic calving events produce tabular icebergs up to several kilometers in length. This process is typical of floating ice shelves in Antarctica and Greenland, whereas grounded ice margins in, for example, Svalbard, produce smaller icebergs much more frequently. There is little evidence that these calving events are related to climate change. Landsat imagery is also used to track the movement of 50 icebergs identified in 1985 imagery of Matusevich Fjord. Iceberg release from the fjord between 1985 and 1994 was extremely slow, with 48 of the icebergs observed in 1985 still trapped in the fjord in 1994. The icebergs from Matusevich Ice Shelf remain in the fjord for many years, probably due to either grounding on submarine moraines or trapping by shore-fast sea ice. Much of the sediment load of the trapped icebergs may be melted out and deposited beneath the sea-ice cover of Matusevich Fjord, and little iceberg-rafted debris of heterogeneous grain size will be transported to the Laptev Sea.

Are vegetation indices useful in the Arctic

This paper describes a preliminary investigation of the extent to which the normalised difference vegetation index (NDVI), derived from satellite optical imagery, can indicate the extent of damage to upland tundra (fruticose lichen and dwarf shrub) vegetation. We combine the results of a previously reported classification of Landsat multispectral scanner imagery from Kolskiy Poluostrov, Russia, with field measurements of the biomass and spectral reflectance of tundra vegetation. The results show that the NDVI is not strongly influenced by biomass, but that differences in species composition and ground cover are significant. Other workers have concluded that vegetation indices are not useful for boreal forests. It is therefore suggested that the use of the NDVI by itself as an indicator of the state of disturbed vegetation in Arctic regions is not recommended.

A Checklist of Bats (Mammalia: Chiroptera) from Lao PDR

This paper provides the first comprehensive review and detailed documentation of available information on the distribution and occurrence of bats in Lao PDR. Information was gathered from literature records, survey data, and museum collections. Detailed locality information, by province (with co-ordinates where available) and maps, along with details on specimens or published references are provided for each species. Based on these records, the bat checklist for Lao PDR comprises 90 species of seven families: Pteropodidae (nine species), Emballonuridae (three species), Megadermatidae (two species), Rhinolophidae (16 species), Hipposideridae (11 species), Vespertilionidae (47 species) and Molossidae (two species). Many of these records have not been previously published and several corrections are provided to previously published records, based on revised identifications as well as new taxonomic information. Nevertheless, many gaps remain in the information available on the bats of Lao PDR. No records were available from two provinces, and many species known from adjacent countries have not yet been documented in Lao PDR; thus, it is anticipated that the species list will increase with further field research.