Forestland connectivity in Romania – implications for management and conservation

Abstract

Forest management rules imposed on all forests in Romania provide habitat conditions for many species across forest landscapes, empirically proven by the high biodiversity of the Carpathians and their surroundings. However, they do not address explicitly the spatial arrangement of forest patches across landscapes and therefore, assessment of connectivity (inside tracts of continuous forest - i.e. intrapatch connectivity - and also among spatially separate patches – i.e. interpatch connectivity) is important. To analyze this, the CORINE Land Cover data set (2012) available for Romania was used. Forest patches were classified into three size categories ensuring survival of tree populations on short term, medium and long term: Interconnectivity Nodes (1,5 to 14,9 ha, minimum 30 m width), Habitat Islands (15,0 ha and 499,0 ha, minimum 100m width) and respectively Habitat Continuum (over 500 ha with a minimum 200m width). Connectivity of each patch to others around was assessed for a maximum threshold distance of 1 km. Further connectivity was classified in terms of its strength (i.e. depending on the size category to which a patch is connected) and quality (i.e. size and structure of resulting connected cluster). Next, distribution of the main forest tree species on the various size, connectivity strength and quality patches of forest vegetation was assessed. Results show a good connectivity of forest patches both in terms of intrapatch connectivity (85% of area is included in HC class) and interpatch connectivity (92,4 % are in 12 clusters over 10.000 ha; among these the one around Carpathians sums up 86,7 % out of the total forest area). Main tree species show a generally good connectivity, better in the mountainous areas than at lower elevations (area in Habitat Continuum patches: 97,5% for Norway spruce vs. 63,3% for pedunculate oak to; strong connection - 97,8% for Norway spruce vs. 67,2 % for pedunculate oak; high quality connectivity - 98,2% for Norway spruce vs. 68,6% for pedunculate oak). These results confirm that management guidelines inherited from the past are providing good conditions for connectivity of forest in general and for main forest tree species. Enforcement of these rules in the future should ensure conservation of species across the forested landscapes at national level and also provide routes for migration in the context of climate change. However, as a large proportion of forestland is today non-state, financial incentives for private owners are a key condition to further accept these restrictions and ensure this major goal.