Forest connectivity for conifer-dependent species

Connectivity analyses

2.7.2.2 Forest connectivity for conifer-dependent species

Unfortunately, the data available for the BPAN project did not allow separation of pine- and spruce-dominated forests from each other for the whole of the BEAR territory, although for some regions, e.g. the Russian part of the BEAR, this would have been possible. Thus, only analysis of “overall coniferous connectivity” was possible.

For the coniferous forest permeability map the re-classification scheme was modified: Broad-leaved and other deciduous forests, as mentioned in Table 64, are considered (at best) as semi-permeable. Forests with a formidable proportion of coniferous trees (coniferous and mixed forests) are classified as permeable.

Permeable forests inside the known high conservation value areas shown on Map 22, have been classified as HCV forests for conifer-dependent species, and form the backbone of connectivity for demanding conifer-dependent species that are dependent on characters and resources found mostly in virgin or natural-like forests only. Other coniferous and mixed forests are normally only semi- or non-permeable for these species, but are non-permeable for many other conifer-dependent species, and were classified as permeable.

The final result is shown in Map 24. The core areas of coniferous and mixed old-growth forests are connected with “permeable” areas of non-old-old-growth coniferous and mixed forests. The map clearly shows that although there are forests with considerable amounts of coniferous trees in Nordland (Norway) they do not have coniferous connections of any kind, either to the coniferous forests elsewhere in Norway or to the main body of the coniferous forests in the BEAR. According to general ecological theory, such conditions make individual forest areas and their species pools very vulnerable to sudden strong disturbances, but simultaneously may create favorable conditions for endemism.

The map also shows that the “overall conifer connectivity” in the BEAR is much stronger than the connectivity of the HCV forests with coniferous trees.

As the coniferous-dominated and mixed old-growth forest and other high conservation value forest areas are known as homes for a wide set of endangered species, which cannot be found in ordinary commercial forests, their connectivity was additionally assessed visually to define and visualize the main connection

Map 24. Forest connectivity for species dependent on conifer trees. u

Nar'yan Mar Arkhangelsk Petrozavodsk

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Mixed and coniferous forests within known HCV

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corridors between known natural core areas with significant amounts of coniferous trees in the BEAR.

Known man-made or natural objects that form a risk of strong negative impact on the function of the ecological connection, either as a true obstacle or as a serious semi-permeable impact, were also assessed.

A rough visual interpretation of key corridors is shown on Map 25. It enables the identification of key obstacles and bottlenecks with the potential to create major barriers for species dispersal over the corridors. Outside the continuous core areas, the corridors were classified into three categories: solid, impaired, and broken.

This was done as an expert evaluation based on such considerations as the distance between core areas, the integrity of the path on the permeable patches between them, the share of permeable patches in the non-integrated path, the conservation adequacy of land use practice, and various human-caused and natural breaks. The result may be somewhat too pessimistic in some places because, as previously mentioned, not all the smaller existing HCV core areas are included. For instance the objects of the Finnish state-land landscape-ecological network, which is specially designed to maintain connections between larger core areas, were not available for the BPAN project. It is noteworthy that the same main “breaks” (due to massive clear-cut areas), which in regard to general forest connectivity were considered only temporary in the long term, will have an obstacle impact on the demanding conifer-dependent species over a much longer time period.

The largest masses of coniferous HCV forest core areas in the BEAR are situated between the White Sea and the Urals, as well as in the Kola Peninsula. In the north of the Russian part of the BEAR the core forests form an almost continuous strip along the northern forest boundary from Lapland in northern Finland to the White Sea in the eastern part of the Murmansk Region (with a break along the Murmansk-Kandalaksha development corridor) and from the White Sea in the Arkhangelsk Region to the Ural Mountains in the Republic of Komi.

South from this latitude strip, the core areas of coniferous forests form a few meridian strips, which form the major south-north forest-ecological mega-corridors in the BEAR. These corridors are continuous in the east, and stepping-stone shaped in the central and western parts of the BEAR. The following major corridors can be identified:

• Wide strip of forests of the Ural mountain range, continuous and relatively well protected

• Arkhangelsk Region-Republic of Komi boundary corridor formed by a few major intact forest landscapes as stepping stones (currently under the highest threat of logging)

• Arkhangelsk Region-Republic of Karelia boundary corridor (core areas on the Onega Peninsula may be regarded as parts of it), which is disconnected

• White Sea west coast corridor, not very well formed

• The corridor along the Finnish-Russian and the Russian-Norwegian border, known as the Green Belt of Fennoscandia; mainly as a chain of stepping-stones, especially in the south

• The corridor along the Scandinavian mountains in Sweden and northern Lapland (Finland), known as the Green Belt of Scandinavia (with several sub-parts with their own names).

The last two form together the so-called “Horseshoe of Fennoscandia” (Midteng 2013).

Map 25. Main corridors for demanding conifer-dependent species. u

Nar'yan Mar Arkhangelsk Petrozavodsk

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SYKE, Transparent World, BPAN Project, 2014 Border of the Barents Region

ransparent World

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Bar ents E ur o- Ar ctic R egion

SYKE, Transparent World, BPAN Project, 2014 0100200300400 km

Nordland

TromsFinnmark Väster- botten

Norrbotten Northern Ostrobothnia Kainuu

Murmansk Region Republic of KareliaRepublic of Komi

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Lapland

Mixed and coniferous forests within known HCV

-forest areas

Other mixed and coniferous forests Connectivity directions Main breaksSolid links Impaired links Broken links

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Map 10 (Land cover in mainland BEAR, see Chapter 2.5.1.) shows in the given scale an absolute predominance of various natural land cover classes in the BEAR.

Such a picture and corresponding pictures for Asian Russia provide a basis for speaking of a large integrated natural tract, embracing the northern part of Pan-Europe from Scandinavia in the west to the Russian Far-East. The phenomenon has been described as the Great Eurasian Natural Backbone (Sobolev & Rousseau 1998). Nevertheless, more detailed analysis shows the situation as much more complex. Map 23, for instance, shows that many forested high conservation value core areas are currently being separated from the remnants of the western (European) part of the Great Eurasian Natural Backbone. Areas non-permeable for demanding species surround core areas and in some cases break possible ecological linkages.

2.7.2.3 Forest connectivity for species dependent on

In document The Characteristics and Representativeness of the Protected Area Network in the Barents Region (sivua 158-162)