Metla Project 3227

Modelling the effect of climate change on phytomass with a GIS

[  Suomeksi  |  Objectives  |  Results  |  Project leader  |  Researchers  |  Publications  |  Metla Research  ]

Duration: 1998-2003   Keywords: Climate change, GIS, modelling, phytomass

Objectives

The project consist of three sub-projects that investigate the effects of climate change and human impact on the transition zone between boreal forests and arctic environment. All the projects carried out by Metla Rovaniemi research station are part of larger research consortium coordinated by Arctic Centre, University of Lapland.

The EC-funded TUNDRA-project (TUNdra Degradation in the Russian Arctic) is multidisciplinary research project that studies global change in the Russian Arctic. The area selected for TUNDRA studies, the Usa-river basin in Komi Republic in East-European Russia, includes major ecotones like taiga forests, arctic and alpine treelines and southern limits of discontinuous and continuous permafrost. The aim of the workpackage carried out by Metla Rovaniemi research station was to primarily focus on compilation of GIS-database of major landscape/vegetation units and associated phytomass in the research area, based on satellite image analysis, regional maps and ground truth data. Phytomass estimates were based on field plot measurements and published information. The regional climate model together with our inventory of landscape/vegetation units and associated data from other research partners were used to establish the relation between present climate and vegetation, and make predictions of vegetation distribution and allocated phytomass under global change. More detailed descripition of the project can be found in Metla's project 8227.

The EC-funded (5th Framework Programme, COPERNICUS2) SPICE-project (Sustainable development of the Pechora region In a Changing Environment) assesses alternative scenarios for the sustainable development of the Pechora region, North-east European Russia. SPICE is coordinated by Arctic Centre, University of Lapland. The Pechora region, which politically includes the North and east of the Komi Republic and the East of the Nenets Autonomous Region, faces considerable challenges both in terms of socio-economic development and environmental conditions. The workpackage carried out by Metla, Rovaniemi Research station aims at
  1. generating land use and cover classification for selected study areas utilizing Landsat TM5 satellite images, ground truth data and digital maps,
  2. calculating indices of landscape structure for these areas and
  3. linking measures of biodiversity in the same areas to landscape structure indices, together with other workpackages in SPICE-project.
More detailed descripition of the project can be found in Metlas project 830701.

The Finnsh Academy funded ARCTICA (Arctic feedbacks to global warming: a circumpolar assessment) aims at assessing possible feedbacks from Arctic land-masses to Global warming. ARCTICA is part of the Finnish Academy research program FIGARE. The workpackage carried out by Metla Rovaniemi research station aims at compiling the GIS-database of major landscape/vegetation units and associated phytomass in three study areas located in the Arctic(-alpine) treeline. Furthermore, statistical models that describe the relation between topography dependent local climate and distribution of vegetation types will be developed.

Results

The aim of the study was to show how a mesoscale vegetation classification of a large sub-arctic area can be conducted at a high spatial resolution (30 m cell size) using a limited ground truth data set. Classification results were compared to global land cover data sets, and the advantages of spatially detailed data sets in studies on different subjects were discussed. The study area is the catchment of the River Usa (93500 km2) in northern European Russia. The river discharges into the River Pechora on the west side of the catchment, and the Ural mountains restrict the area in the east. Vegetation zones in the Usa basin range from taiga in the south to forest-tundra and tundra in the north and alpine in the east. Vegetation and land cover classification for the Usa basin was produced by a supervised method using a mosaic of several, spectrally adjusted Landsat TM5 images from five different dates. Ground truth data were collected during summers 1998, 1999 and 2000. Classification accuracy was tested against test points of different vegetation types recognised from oblique aerial photos taken from a helicopter. We produced a classification of 21 vegetation type/land cover classes. According to our accuracy test, the main vegetation types (forests, willow dominated stands and meadows, peatlands, tundra heaths, mainly unvegetated areas, and water bodies) can be separated to a relatively high accuracy: 84% of the test points were classified correctly. The main conclusions of the study are that the vegetation and land cover classification data conducted in the project can be effectively used in a wide range of landscape analysis and process modeling studies. Comparisons of our data to global vegetation and land cover data sets suggest that global data constructed without proper field knowledge can be misleading. We suggest that the accuracy of such data should be evaluated before using them in regional studies

Another aim of the study was to model the climate dependent occurrence of vegetation. GIS-based data sets were used to analyze the structure of the forest line at the landscape level in the lowlands of the Usa River Basin, in Northeast European Russia. Vegetation zones in the area range from taiga in the south to forest-tundra and tundra in the north. We constructed logistic regression models to predict forest location at spatial scales varying from 1 x 1 km to 25 x 25 km grid cells. Forest location was explained by July mean temperature, ground temperature (permafrost), yearly minimum temperature, and a Topographic Wetness Index (soil moisture conditions). According to the models, the forest line follows the +13.9°C mean July temperature isoline, whereas in other parts of the Arctic it usually is located between +10 to +12°C. It is hypothesized that the anomalously high temperature isoline for the forest line in Northeast-European Russia is due to the incapability of local ecotypes of spruce to grow on permafrost terrain. Observed patterns depend on spatial scale, as the relative significance of the explanatory variables varies between models implemented at different scales. Developed models indicate that with climate warming of 3°C by the end of the 21st century temperature would not limit forest advance anywhere in our study area.

Project leader: Nikula, Ari
The Finnish Forest Research Institute, Rovanniemi Research Unit, PL 16, 96301 Rovaniemi
Phone: +358 10 211 4418 Telefax: +358 10 211 4401
E-mail: ari.nikula@metla.fi

Other researchers: Mikkola, Kari, RO (1998-2003), Virtanen, Tarmo, RO (1998-2003)


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Updated 30.12.2006
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