ABSTRACT. The interior of southern Baffin Island between 64˚N and 68˚N latitude is a mainly lowland area over 50 000 km 2 in extent, containing two large lakes (Amadjuak and Nettilling) and numerous smaller lakes and ponds. This area is important as summer range for caribou and a variety of birds, and there is evidence for a human presence as early as 3000 B.P. Field studies between 1984 and 1988 and the operation of climatic autostations from 1987 to 1995 revealed a warm summer climate and cold winters. There is a locally rich and diverse vegetation, including Betula glandulosa and other species that are indicative of the low arctic bioclimatic zone and mark the present northern limit of that zone in the eastern Canadian Arctic. Air photos and Landsat imagery were used to map vegetation beyond the field areas, leading to an estimate of 46% of the land area in continuous vegetation (tundra) of some type and 15% with shrub and heath elements. Palynology of sediment cores taken from Nettilling Lake permitted extrapolation from present bioclimatic conditions to 4750 years B.P. Betula and therefore elements of a low arctic vegetation association appear to have been present in the area during most of that period, indicating a local bioclimatic system that has been relatively stable under regional variations of climate.Key words: Baffin Island, Nettilling Lake, low arctic vegetation, bioclimate, remote sensing, palynology, automatic climate station, climate change RÉSUMÉ. La région intérieure du sud de la terre de Baffin située entre le 64˚ et le 68˚ de latit. N. est essentiellement une zone de basses-terres s'étendant sur plus de 50 000 km

Changes along the margin of the southern half of the 5900 km2 Barnes Ice Cap have been assessed using 1993 Landsat TM imagery in comparison with digitized 1:50 000 NTS maps based on 1961 photogrammetry. The average recession over the 183 km long southern perimeter was found to be at least 4 m a−1, with no significant difference between the southeast and southwest sectors. Viewed in conjunction with the sustained retreat previously reported for the northwest margin, these results indicate that a general reduction in the size of Barnes Ice Cap is occurring. The present retreat phase began under a regional climate warming in the late 19th to early 20th century period and continues, while the record of the ablation-season temperature since the mid-century has not shown any significant trend.

Abstract:The analysis of a series of five normalized difference vegetation index (NDVI) images produced information about a Labrador (Canada) portion of the tundra-taiga interface. The twenty-five year observation period ranges from 1983 to 2008. The series composed of Landsat, SPOT and ASTER images, provided insight into regional scale characteristics of the tundra-taiga interface that is usually monitored from coarse resolution images. The image set was analyzed by considering an ordinal classification of the NDVI to account for the cumulative effect of differences of near-infrared spectral resolutions, the temperature anomalies, and atmospheric conditions. An increasing trend of the median values in the low, intermediate and high NDVI classes is clearly marked while accounting for variations attributed to cross-sensor radiometry, phenology and atmospheric disturbances. An encroachment of the forest on the tundra for the whole study area was estimated at 0 to 60 m, depending on the period of observation, as calculated by the difference between the median retreat and advance of an estimated location of the tree line. In small sections, advances and retreats of up to 320 m are reported for the most recent four-and seven-year periods of observations.

Thematic maps derived from remote sensing must be relevant to their users. The accuracy of classification rubrics closely relates to the understanding a person has of a feature's physical characteristics, use and cultural meaning. Geographical concepts incorporated in traditional ecological knowledge are learned through experience of the land and communicated orally. This article examines the cultural dimension of remote sensing-derived information. A series of Anishinaabe terms are put in the context of the remote sensing-based classification systems developed for the US National Land Cover Database (NLCD) 2001 and the Atlas of Canada. The NLCD 2001 better represents Anishinaabe descriptions of geographical features. Its simplicity makes it more inclusive, particularly with the classification of exposed soils, forest types and wetlands. This classification scheme uses nominal information and has no climate-or region-specific categories. The results suggest that a foundation exists for Aboriginal people to benefit from remote sensing technologies from which to extract information compatible with their knowledge of the landscape. Representation in remote sensing classifications 493 des correspondancesétroites entre les descriptions Anishinaabe et un système de classification comportant des données nominales et excluant des catégories relatives aux conditions climatiques ou aux régions. Les résultats montrent qu'une assise est en place, laquelle permettrait d'exploiter la télédétection de la couverture terrestre en fonction de connaissancesécologiques traditionnelles autochtones.

Changes along the margin of the southern half of the 5900 km2Barnes Ice Cap have been assessed using 1993 Landsat TM imagery in comparison with digitized 1:50 000 NTS maps based on 1961 photogrammetry. The average recession over the 183 km long southern perimeter was found to be at least 4 m a−1, with no significant difference between the southeast and southwest sectors. Viewed in conjunction with the sustained retreat previously reported for the northwest margin, these results indicate that a general reduction in the size of Barnes Ice Cap is occurring. The present retreat phase began under a regional climate warming in the late 19th to early 20th century period and continues, while the record of the ablation-season temperature since the mid-century has not shown any significant trend.