Multi-scale Analysis of Forest Fragmentation in Lithuania

Forest fragmentation, which is usually defined as a landscape scale process that involves both loss of forest and its fragmentation per se, is important for understanding of ecological function and process. We performed a multiple-scale analysis of forest fragmentation based on 30 m spatial resolution forest/non-forest cover raster maps, derived from CORINE Land Cover database in Lithuania. We calculated forest fragmentation indexes within the fixed-set of non overlapping analysis blocks of five sizes (2.25, 7.29, 65.61, 590.49, and 5,314.41 ha) and classified them with certain category of fragmentation. Fragmentation assessed using proportion of forest was scale-dependent. In 2.25 ha size blocks 60.9% of all forest was classified as "inner" (those were at least 90% forested), but decreased rapidly in large blocks, so that less than 2% of this class were found in 5,314.41 ha blocks. The decrease of "dominant" forest (those were at least 60% forested) along the scale was less steep. In 2.25 ha blocks share of the "dominant" forest was 74.9 %, while in 5,314.41 ha blocks - 30.1 %. Fragmentation of forest landscape assessed by using two fragmentation components (proportion of forest and connectivity) was scale-dependent, more or less. Most Lithuanian forest was in fragmented landscapes. In the mid-size blocks (7.29 ha and 65.61 ha) 35.3% and 8.1%, of all forest was contained in a fully forested ("interior") blocks, while 22.6% and 27.2% was attributed to an "edge", 28.0% and 48.0% - "patch", respectively. Share of "interior" forest was smaller in larger blocks, with less than 1% of forest was classified as interior in 5,314.41 ha blocks while proportion of "patch" forest reached 74.4% at this scale. Though, relatively less fragmented forest landscapes were in the south-eastern part of the country, our results suggest that fragmentation is so prevalent it could potentially influence ecological processes on most forest landscapes of Lithuania.