A vegetation‐based method to map climatic variation in the arctic–boreal transition area of Finnmark, north‐easternmost Norway

• Published in: Journal of Biogeography
• Main Authors: Karlsen, Stein Rune, Elvebakk, Arve, Johansen, Bernt
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2005
• Subjects: Arctic; Norway; Varangerhalvøya; Finnmark; Varangerhalvøy*
• Online Access: http://dx.doi.org/10.1111/j.1365-2699.2004.01199.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-2699.2004.01199.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2699.2004.01199.x

Abstract Aim To develop a new method for bioclimate mapping where the vegetation layer is the main source of climate information. Location The study area includes four subareas, all situated on the Varangerhalvøya peninsula in Finnmark, north‐easternmost Norway (70–71° N). The four subareas were chosen to represent most of the climatic, topographic, geomorphologic and botanic diversity along the arctic–boreal gradient in the area. The four meteorological stations in the area show a climatic gradient with mean July temperature ranging from 10.1 to 12.3 °C. Methods The new vegetation‐based method is based on the fact that most plant species and plant communities both in the Arctic and adjacent areas have a distribution pattern limited by temperature to some extent. The vegetation is mapped using Landsat TM data and a contextual correction process in a geographic information system. The mapped vegetation units are defined as temperature indicators based on their total distribution patterns and the temperature indicator value of their high frequency and dominant species. The indicator value and degree of cover of all thermophilous vegetation units, within each 500 × 500 m study unit, are combined in a Vegetation‐based Index of Thermophily, VI tm . This new vegetation‐based method is based on the same basic idea as a recently published floristic‐based method for calculating a Floristic‐based Index of Thermophily, FI tm . The VI tm values are tested by comparison with the FI tm values, and temperature data collected in the field during two growing seasons, and the differences are interpreted ecologically. Results Twenty‐one of the mapped vegetation units were defined as thermophilous and categorized in five groups of temperature indicators. The VI tm values showed a strong positive linear relationship with the temperatures measured during the years 2001 and 2002, with r 2 values of 0.79 and 0.85, respectively. The VI tm values show a high linear relationship ( r 2 = 0.76) with the 71 study units where the FI tm values ...