Satellite Based Capercaillie Habitat Modelling for Monitoring of Biodiversity in Swedish Forests
Thulin, Susanne1; Wester, Kjell1; Edman, Björn2; Mild, Krister3; Blanck, Henrik4; Edlund, Jonas5; Almqvist, Kaj5; Svensson, Hans6; Hägerroth, Jan-Eric7
1Brockmann Geomatics Sweden AB, SWEDEN; 2Rheoconsult, SWEDEN; 3Swedish Environment Protection Agency, SWEDEN; 4County Adm. Board of Jönköping, SWEDEN; 5Norrköping Municipality, SWEDEN; 6H.S, SWEDEN; 7J-E.H, SWEDEN
The Capercaillie (Tetrao urogallus) requires sizable habitats consisting of a mosaic of mature open pine forest, multi-layered conifer forests and sparsely wooded mire edges (figure 1).
Figure 1) Capercaillie in typical forest environment.
Such areas also house many other less conspicuous but equally important animals, plants and insects. The conservation of such umbrella species is assumed to guarantee the protection also of other biological values. Biodiversity values can be monitored and maintained by careful planning and management of these core sites over time.
To fulfil the national and regional environmental goals and management of Natura 2000 areas, SEPA, regional and local Administrations need cost-effective methods that can produce comparable results at regular intervals.
Satellite (Landsat TM/ETM) and GIS data are used to produce vegetation maps optimal for translation to parameters suitable for modelling of Capercaillie essential habitats. Habitat Suitability Index* (HSI) values (0-1.0) are derived and together with assessment of adjacent values, the areal demand for certain parameters can be incorporated in the analysis (figure 2).
Figure 2) Schematic description of method for deriving HSI values.
The maps below for 1989 and 2005 show HSI values 0.5-1.0 in colour indicating areas suitable for the Capercaillie overlayed with lek inventory data from two different time periods (figure 3). The decrease in number of displaying Capercaillie males between the two dates corresponds well to the decline in suitable habitat.
Figure 3) Capercaillie habitat suitability maps for 1989 and 2005, with the highest HSI values in dark green/red and < 0.5 in grey (using a 50 hectare moving window filter to integrate a neighborhood aspect). Field inventory data from leks (blue lines) are shown with the number of displaying males from 1993-1999 (top image) and 2004-2006 (bottom image). Red rings represent habitat areas (radius 1 kilometer) surrounding the leks.
Appropriate presentation and visualisation of the habitat modelling results have been developed in close cooperation with the end users, using for example very high resolution imagery (VHR), e.g Quickbird and/or shaded relief models from the laser data, to provide important background and context to the HSI index/suitable habitats. Robust Capercaillie habitat models will ultimately pave the way for combining models of habitats derived for several species to identify and monitor core sites for maintenance of biodiversity values in Swedish forests.