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Tag: Vegetation

Vegetation density/distribution in the high Arctic Vegetation density/distribution in the high Arctic
The current vegetation density and distribution in the high Arctic can be calculated using satellite images. The vegetation index, 'greenness' (NDVI) represents a benchmark of the presence and ratio of photosynthesis. In monitoring the vegetation, scientists can keep an eye on the situation and use the index as an indicator of climate change - increased temperatures would enable the forest and tundra to move further north.
31 Jul 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Increases in annual temperatures for a recent five-year period, relative to 1951-1980 Increases in annual temperatures for a recent five-year period, relative to 1951-1980
Warming is widespread, generally greater over land than over oceans, and the largest gains in temperatures for the planet are over the North American Arctic, north central Siberia, and on the Antarctic Peninsula. These recent increases in temperature are confirmed by changes in other features: loss of sea ice, shift of tundra to shrub vegetation, and migration of marine and terrestrial ecosystems to higher latitudes.
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
3
Vegetation and land cover in the Arctic Vegetation and land cover in the Arctic
The land mass in the Arctic - Greenland and parts of Canada, Alaska, Russia and the Nordic countries - surrounds the Arctic Ocean. In the low Arctic, down to the temperate regions, the taiga coniferous forests represents a vast band of deep forests. North of the taiga, the tundra of the Arctic - with low vegetation, shrubs and various degrees of permafrosts spreads out. Beyond the tundra, there might be barren regions with only rock and few plant...
31 Jul 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
5
Temperate Forests Temperate Forests
Temperate forests are active carbon sinks and deforestation in the temperate zone has largely stopped. Where demand for land and/or water allows, reforestation would enable carbon sequestration and could provide other benefits including higher biodiversity and recreation opportunities.
13 Sep 2009 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Invasive species response to climate change - Hydrilla spp, current and 2080 habitat suitability Invasive species response to climate change - Hydrilla spp, current and 2080 habitat suitability
As climate change alters Arctic ecosystems and enables greater human activity, biological invasions are likely to increase in the Arctic. To some extent, Arctic terrestrial ecosystems may be predisposed to invasion because many invasive plants are adapted to open disturbed areas. Range map scenarios developed for 16 highly invasive plants either occurring in or at risk of invading Alaska also paint a sobering outlook for the future. This map dep...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
5
Trends in vegetation biomass, Ellsmere Island 1995-2007 Trends in vegetation biomass, Ellsmere Island 1995-2007
Data from many sources and at several scales suggest that recent climate change is already affecting terrestrial Arctic ecosystems. Comparisons of historical and contemporary aerial photographs provide evidence that Arctic vegetation has already undergone significant shifts in recent decades, foreshadowing changes that are likely to come. In a repeated measurement study conducted on Ellesmere Island, Nunavut, Canada, over a period of 13 years, t...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
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Definition of the geographic areas covered in the Arctic Biodiversity Assessment Definition of the geographic areas covered in the Arctic Biodiversity Assessment
The Arctic Council study on trends in the polar ecosystems - the Arctic Biodiversity Assessment (ABA) focuses on the areas displayed in this map. The high- and low Arctic regions are defined from the bioclimatic zones in the Circumpolar Arctic Vegetation Map (CAVM), while the sub-Arctic zone is the area definition that has been used int he Arctic Council.
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
4
Peatland in Arctic Russia Peatland in Arctic Russia
Wetlands are widely distributed in the Arctic, covering about 70% of the region. Of the six Ramsar wetland types represented, the most extensive are forested and non-forested peatlands. Peatlands are wetlands where organic matter (peat) derived from dead and decaying plant material has accumulated and remains stored under conditions of permanent water saturation. Those which still have peat-forming vegetation are known as mires, and can be divide...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
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Advancement of phenological events in high-arctic Greenland Advancement of phenological events in high-arctic Greenland
It is clear from lower latitudes that phenological trends are linked to temperature changes and experimental warming also results in earlier plant phenology. Yet, in Arctic and alpine ecosystems, the melting of the winter snow pack rather than temperature per se determines the onset of biological activity like the timing of flowering in plants and emergence in invertebrates. As such, the phenology of these groups of organisms, or taxa, could be a...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
3
Reindeer herding - vegetation impacts (Norway and Finland) Reindeer herding - vegetation impacts (Norway and Finland)
A very high-resolution false color Ikonos-2 satellite image of Jauristunturit in the border zone shared by Norway and Finland. Image acquired 28 June 2001. The main vegetation type is lichen dominated tundra heath with dwarf shrubs. The difference in whiteness is due to lichen coverage, and the national border with reindeer fence visibly divides the area. The northern portion is Norway, where fruticose lichen coverage is higher. This is a consequ...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
4
Trends in Arctic vegetation productivity 1982-2005 (Greening of the Arctic) Trends in Arctic vegetation productivity 1982-2005 (Greening of the Arctic)
Arctic vegetation has undergone enormous change in the past, most notably in response to the glacial and interglacial periods of the Quaternary. Data from many sources and at several scales suggest that recent climate change is already affecting terrestrial Arctic ecosystems. Comparisons of historical and contemporary aerial photographs provide evidence that Arctic vegetation has already undergone significant shifts in recent decades, foreshadowi...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
5
Arctic terrestrial species trends 1970-2005 (ASTI) Arctic terrestrial species trends 1970-2005 (ASTI)
Dramatic changes, such as sea ice loss, are projected to occur in Arctic ecosystems over the next century. Understanding how the Arctic’s living resources, including its vertebrate species, are responding to these changes is essential in order to develop effective conservation and adaptation strategies. Arctic species that are adapted to these extreme environments are expected to be displaced, in part, by the encroachment of more southerly specie...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
3
Invasive species response to climate change - Hydrilla spp, current and 2080 habitat suitability Invasive species response to climate change - Hydrilla spp, current and 2080 habitat suitability
As climate change alters Arctic ecosystems and enables greater human activity, biological invasions are likely to increase in the Arctic. To some extent, Arctic terrestrial ecosystems may be predisposed to invasion because many invasive plants are adapted to open disturbed areas. Range map scenarios developed for 16 highly invasive plants either occurring in or at risk of invading Alaska also paint a sobering outlook for the future. This map dep...
01 Nov 2010 - by Hugo Ahlenius, UNEP/GRID-Arendal
3
Vegetation and land cover in the Arctic Vegetation and land cover in the Arctic
The land mass in the Arctic - Greenland and parts of Canada, Alaska, Russia and the Nordic countries - surrounds the Arctic Ocean. In the low Arctic, down to the temperate regions, the taiga coniferous forests represents a vast band of deep forests. North of the taiga, the tundra of the Arctic - with low vegetation, shrubs and various degrees of permafrosts spreads out. Beyond the tundra, there might be barren regions with only rock and few plant...
13 Oct 2010 - by Hugo Ahlenius, UNEP/GRID-Arendal
4
Vegetation zones in the Arctic Vegetation zones in the Arctic
The Circumpolar Arctic Vegetation Map (CAVM) project is an international effort to map the vegetation and associated characteristics of the circumpolar region, using a common base map. The base map is a false colour infrared image created from Advanced Very High Resolution Radiometer (AVHRR) satellite data.
17 May 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
3
Definitions of the Arctic Definitions of the Arctic
Several definitions of the Arctic as a region exist and are all used extensively. Definitions of the geographic boundaries of the Arctic vary, including such definitions as the area with a July isotherm below 10º C, vegetation distribution (tundra) or political boundaries, such as the definition by CAFF (CAFF, 2001). Nowhere else on Earth do we find such vast areas of relatively undisturbed marine and coastal ecosystems.
17 May 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Lake Chad - decrease in area 1963, 1973, 1987, 1997 and 2001 Lake Chad - decrease in area 1963, 1973, 1987, 1997 and 2001
Straddling the borders of Nigeria, Chad, Niger and Cameroon in West Africa, Lake Chad has been a source of freshwater for irrigation projects in all these countries. This graphic traces the shrinkage of Lake Chad and changes in vegetation from 1963 to 2001. It includes maps of the lake from 1963, 1973, 1987, 1997 and 2001. Climatic changes and high demands for agricultural water are responsible for the lake's shrinkage.
17 May 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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The greening of Niger - trends in vegetation The greening of Niger - trends in vegetation
The Sahel region of Africa, a belt of savanna ecoregion south of the Sahara desert, stretched from coast to coast. This region is not only known for long spells of drought (and desertification), but also from housing some of the World's poorest countries. Recent trends show good signs on the recovery of the region, and the relative vegetation index (NDVI) presented for the country of Niger in this map shows increases in the period from 1982 to 19...
07 Nov 2006 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Lake Chad - decrease in area 1963, 1973, 1987, 1997 and 2001 Lake Chad - decrease in area 1963, 1973, 1987, 1997 and 2001
Straddling the borders of Nigeria, Chad, Niger and Cameroon in West Africa, Lake Chad has been a source of freshwater for irrigation projects in all these countries. This graphic traces the shrinkage of Lake Chad and changes in vegetation from 1963 to 2001. It includes maps of the lake from 1963, 1973, 1987, 1997 and 2001. Climatic changes and high demands for agricultural water are responsible for the lake's shrinkage.
11 Jul 2006 - by Philippe Rekacewicz and Hugo Ahlenius UNEP/GRID-Arendal
3
Lake Chad: almost gone Lake Chad: almost gone
Straddling the borders of Chad, Niger and Cameroon in West Africa, Lake Chad has been a source of freshwater for irrigation projects in each of these countries. Maps drawn from a series of satellite images show a dramatic decrease in the size of the lake over the past 30 years. Since 1963, the lake has shrunk to nearly a twentieth of its original size, due both to climatic changes and to high demands for agricultural water. Since 1963, the surfac...
06 Nov 2009 - by Philippe Rekacewicz (Le Monde diplomatique), February 2006
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