Abstract: Estonian Forestry Development Programme set in 2003 ambitious goal that area of strictly protected forests should increase at least to 10% from total forest area in Estonia before 2010 by expanding the area of old-growth under protection, improving the representativeness of conservation areas and establishment of large conservation sites. Inventory of forests was carried out on existing and possible new conservation areas within the Estonian Forest Conservation Area Network project (EFCAN) in 1999-2001. EFCAN project had remarkable results. The share of strictly protected forests has increased to 7.8% of total forest area by 2009 and the network of conservation areas is quite well covering all forest ecosystems in Estonia. Several selected areas are still not protected for different reasons. These areas should still be considered for protection as the areas may lose their conservation value. Several forest types(meso-eutrophic, eutrophic boreo-nemoral and eutrophic paludifying forests) should have larger area for conservation and large disturbance areas (wind damage, forest fire) should be also included into the network.
Key words: Forest conservation, biological diversity, ecological network.
1. Introduction
The diversity of today’s forests is the result of complex historical interactions between a number of physical, biological and social factors—the dynamics of cyclical ecological processes, species and ecosystems, and human activities [1]. The key factor designing of forest landscapes has been human activity in the past few millennia. Forestry generates benefits for society by the existence of certain forest types and their attributes [2] and this can be seen as production, environmental and social aspects of forestry. Almost all forests are managed nowadays and thus rational management policy is crucial. Public interest on forestry has been rising within last decades. This has introduced participatory planning method involving interest groups and considering more forest functions in forest management. Also this means more extensive data assessment and efforts for biodiversity conservation of forest ecosystems. Classical nature conservation has acquired a new and broader context nowadays–protection of species and communities is more addressed to the framework of preservation of biological diversity [3]. In balanced forestry, the first and perhaps most critical step for biodiversity considerations are to leave some of the forest landscape untouched in reserves [4]. Designing representative reserve systems is a complicated task involving many steps and decisions. Researchers now agree that biodiversity protection should be considered in reserve network design [5].
Estonia forms a part of the hemiboreal vegetation zone [6]. Historically, forests covered approximately 85% of Estonian land area [7]. In 2006, forest land covered 2.25 million ha, i.e., 51.5% of the Estonian land area [8]. Estonian forests are quite variable because of differing water regimes and soil conditions. Also the commonly used management regimes have made the forests even more variable. Average size of a forest stand is around 1.2 ha, influenced and designed also by the average size of cutting areas.
Estonian Forest Policy [9] set an objective in 1997“to conserve valuable ecosystems and to maintain forest biodiversity the size of strictly protected areas will gradually be increased from the present level of 3% of total forest area to at least 4% in order to expand the area of old-growth under protection, to improve the representativeness of conservation areas, and to establish large, contiguous conservation sites”. Inventory of forests was carried out on existing conservation areas and on possible new conservation areas within the Estonian Forest Conservation Area Network project (EFCAN) in 1999-2001. The EFCAN inventory covered 156,600 ha of forests on nature conservation areas and potential new conservation areas. 2.8 percent of stands were considered as forests with high nature value. Detailed inventory of forest species was carried out on the areas of high nature value and the lists of species of vascular plants, bryophytes, lichens, fungi, insects and birds were drawn up in this inventory. Estonian Forestry Development Programme [10] set in 2003 more ambitious objective that area of strictly protected forests should increase at least to 10% from total forest area before 2010.
In this paper, we evaluate success and drawbacks of EFCAN project. Our aims are (1) to determine current conservation status of EFCAN selected additional areas for conservation; (2) to analyze the representativeness of strictly protected forests on conservation areas; (3) to analyze the method of nature value assessment of EFCAN; (4) to evaluate additional need for strictly protected forests in Estonia; (5) to analyze gaps in ecological network of forest conservation areas.
2. Materials and Methods
2.1. EFCAN Inventory of Existing and Possible New Forest Conservation Areas
EFCAN project had an objective to identify possibly valuable forest areas and assign them to forest conservation by common legal procedures. This objective consisted from different tasks:
(1) valuable forest ecosystems and old-growth forests should be found and inventoried;
(2) nature values of specific forest stands and landscapes should be assessed;
(3) conservation possibilities and management options of specific areas should be analysed;
(4) geographical and typological representativeness of conservation sites should be analysed;
(5) legal procedures of creating new conservation areas and/or changing present conservation areas.
From the total forest area 140,100 ha or 241 new possible areas were defined in forests as pre-selected areas in 1998. In order to find out to what extent the areas selected would improve the typological representativeness of forests growing in the existing protected areas, the surface area of these type groups was calculated on the basis of the pre-selected areas located in state forests. In the selected area, all old-growth, natural and recovering forests were identified and described, along with all key habitats and potential key habitats found; their location was assured with the GPS measurements. If necessary, forest survey data of inventoried area was corrected.
The EFCAN inventory covered 81,800 ha of forests on nature conservation areas in 1999 and 74,800 ha of forests with potential for conservation areas in 2000. EFCAN inventory was focused on state-owned forests. Detailed inventory of forest species was carried out in the total of 3,500 ha of areas of high nature value, and the lists of species of vascular plants and bryophytes, lichens, fungi, insects and birds were drawn up in this inventory. Quality of the inventories was assessed by random control measurements on 2% of inventoried area.
As a result of the work of the EFCAN project it was proposed that in addition to the strictly protected forests in the existing conservation areas, strict protection should be secured also for additional 29,176 ha of forest, and the total of 8,645 ha of forest should be designated as support areas for the EFCAN. The proposal for additional protection covers 136 areas in total. The proposed additional conservation areas contain the total of 1,355 ha of forest communities that are rare and need protection, 2,529 ha of key habitats, potential key habitats and recovering forest communities, and 8,634 ha of habitats corresponding to the habitat types listed in Annex I of the EU Habitats Directive [11].
Boundaries of areas of potential value for designation as strict reserves were determined on maps containing separate layers for all stands conforming to the conditions of pre-selection. Principles of determination of boundaries were formulated in rather general wording to leave space for additional expert evaluations. In selecting the areas, preference was given to areas:
(1) with a larger percentage cover of stands conforming to higher-priority criteria of pre-selection;
(2) where stands conforming to pre-selection criteria were located closely together and were not fragmented with private lands or other land use types;
(3) adjoining the existing protected areas;
(4) located further from settlements;
(5) with a larger surface area.
The minimum size of the selected area was 100 ha. Data on smaller areas were forwarded to the Woodland Key Habitats Project [12] as potential key habitats for more detailed inventory. Roads, rivers, compartment boundaries, boundaries of land use units and other landscape marks clearly distinguishable in the nature were delineated as new areas.
2.2. EFCAN Method of Nature Value Assessment
The EFCAN method is based on evaluating specific stand and landscape parameters and scoring the results on a scoreboard (Fig. 1). The method proved to be reliable for general assessment of forest nature value. Regardless of the subjectivity of estimating the quantitative and qualitative parameters of a forest stand, the total score assists the decision making on the nature value of the stand. This applies to the evaluation of the naturalness and level of human influence in a stand as well as indication for habitat of threatened or rare species. Viilma et al. [13] have described this method in more detail.
In addition to scoring result an expert opinion on forest naturalness was given. Naturalness was defined as different levels of anthropogenic influence in a forest stand. This should be not necessarily interpreted as biodiversity level in the stand as well as managed forests may have high biodiversity levels also, but signs of management activities should be clearly visible in managed stands. Forests were classified as old-growth forests, natural forests, recovering forests and managed forests. Unmanaged forests are non-anthropogenic originated and have species composition characteristic to site conditions, there can be signs from previous management activities, but these have no significant importance for stand structure and development. As most forests in Estonia have already been managed or heavily human influenced therefore we mean under “old-growth forests” the remnants of long-time (at least for last 200 years) unmanaged forests. According EFCAN full-scale inventory there are several hundred hectares of such“old-growth forests” still existing in Estonia [13].
Old-growth forests and natural forests were concurrently regarded also as key habitats, while recovering forests were regarded as key habitats or not, depending on their condition. A key habitat is an area where is a great probability of occurrence of endangered, vulnerable or rare species. A potential key habitat is an area that will become a key habitat within few decades if it is managed in a way to promote its biodiversity values [12]. Decisions on key habitats are based on the occurrence of indicator species and species with narrow ecological amplitude (i.e. habitat specialists), features of natural forest and historical background of the forest. Due to reasons related to site conditions, certain types of key habitats have to be determined on the basis of indirect features, without using indicator species, e.g., dry pine stands, where the number of indicator species is small; the rare habitat specialists occurring there are mainly beetles which detection often requires special knowledge and skills. The size of a key habitat is not limited, e.g., it could be a single tree or a forest area of several hectares. 2.3. Analysis of the EFCAN
Analysis of the EFCAN is based on criteria for selection of protected forest areas [14] dedicated to biodiversity conservation according to representativeness, spatial design and habitat suitability. Process of integrating EFCAN areas into existing conservation area network is analyzed. Status on current nature conservation areas was assessed using public information sources as Forest Register, Environmental Register as well as specific databases (National Forest Inventory database, state forest stand register etc.). If conservation status was secured on full proposed area in 2009 this EFCAN area was considered as protected. If conservation status was secured only on a part proposed area and unsecured area was less than 10 hectares then this EFCAN area was considered as protected area. If unsecured area was bigger then the area was considered as partially protected.
The analysis of representativeness of strictly protected forests was done to find possible gaps in the representation of forest types (habitats). The forest site type groups are specified by the forest classification by Erich L?hmus [15]. Theoretical forest conservation need by site type groups was taken from the work of Asko L?hmus et al. [16].
Spatial design was analyzed with GIS methods. Area size, connectivity, patchiness, habitat mosaics were assessed. Habitat fragmentation and spatial correlation between patch populations can be usually simulated for selected species [17]. The problem is formulated with habitat connectivity affecting population characteristics, with spatial correlations accounted with nonlinear algorithms. Ecosystems and habitats are more complicated systems for this type of modelling therefore mosaic of patches of old-growth forests was assessed visually and only possible dispersal obstacles were identified in this study.
Habitat suitability and site conditions were assessed as forest naturalness (vegetation integrity) and stand structural complexity (scoreboard method) during field inventory. Inventory results were analyzed and summarized by EFCAN areas.
3. Results
3.1 Analysis of the Network
The EFCAN proposal for additional forest conservation areas was 136 areas in total. From these areas conservation is secured on 97 areas completely and 21 areas partly in 2009 (Table 1). Partly means that conservation area covers only a part of EFCAN proposed area because landowner did not agree the conservation status or area’s conservation value was too low. Still 18 EFCAN proposed areas have no conservation.
The analysis of strictly protected forests revealed important gaps in the representation of forest types(Table 2). Mesotrophic forests make up more than 25% of strictly protected forests. Strictly protected bog forests together with transition areas between forests and bogs form also approximately 25% of strictly protected forests. Strict reserves include 16,800 ha of drained peatland, which is not a natural type. The total share of stands belonging to the class of peatland forests—bog forests, swamp forests and drained peatland forests–is more than 32% of strictly protected forests, while these forests make up 39% of the total area of forests in Estonia. Theoretically the total minimum area of strict forest reserves was estimated 8.5% of the forest land [16]. Current reserves cover 92% of the theoretical total need but they are in misbalance by site conditions. The largest gaps are for the forests on fertile soils (meso-eutrophic boreal, eutrophic boreo-nemoral and eutrophic paludifying forests) and swamp forests. In contrast, heath and oligotrophic paludifying forests have much higher conserved area than the estimated minimum need.
Meso-eutrophic forests are the most intensively managed forests together with mesotrophic forests in Estonia, also these forests cover large area in privately owned land, and therefore is quite complicated to establish new conservation areas aiming these site types. It is relatively difficult to find eutrophic boreo-nemoral forests for additional conservation because these sites are quite small and fragmentary.
The spatial distribution of nature protection areas is quite well balanced and representative (Fig. 2). Present NPA (national parks, nature conservation areas, landscape protection areas) are varying by size. Fifteen NPA are larger than 10,000 ha forming 54% the total area (Table 3). There are many tiny NPA with area less than 100 ha, together accounting less than 1% of total area. As EFCAN inventory found that only 2.8% of stands are forests with high nature value on NPA, tiny areas with specific and high nature value should also be protected.
In addition to NPA, many small areas have conservation status also. NATURA 2000 sites and permanent habitats of protected species are protected by the law as well as woodland key habitats by conservation agreements between state and landowner(ad hoc protection). Protection of key habitats and low intensity near-natural management of commercial forests have formed a representative ecological network of forest conservation areas. Possible obstacles for some species in this network are three major roads and two big rivers (Fig. 2).
Establishment of EFCAN improved the territorial representativeness of protected forest areas and especially in several counties. The forests of few counties will remain less represented due to the fragmentation of forests, more intensive economic activity and a high percentage of private forests in the counties.
3.2. Nature Value Assessment
The EFCAN method proved to be reliable for general assessment of forest nature value. Regardless the subjectivity of estimating the quantitative and qualitative properties of a forest stand, the total score assists decision-making about the nature value of the stand and selection of proper management regime. This applies to the evaluation of the naturalness of stand as well as indication for habitat of rare species.
The method is suitable for large-scale inventories but interpretation of total scores is dependent from forest site type. The method works well in fertile forest site types and relatively well in poor paludified and peatland forests. The method seems to be not working in alvar and boreal heath forests.
The study showed that it is almost impossible to distinguish between recovering forests and commercial forests if they are (potential) key habitats, also distinguishing key habitat and potential key habitat is impossible with this method. The margin between natural and recovering forests scores 34 points in fertile sites and 25 points in poor sites. The margin between a(potential) key habitat and a forest with no key habitat scores 15 points on fertile sites and 8 points on poor forest sites. The margin between old-growth and natural forests is 50 points on fertile sites and 35 points on poor sites and the margin between managed and recovering forests 18 points on fertile sites and 10 points on poor sites [18]. Table 4 presents the principal scale for naturalness of a forest stand with this method.
4. Discussion
The loss of biological diversity is characterized by degradation of nature values in forests [19]. The main method of preserving biological diversity is still restriction of the use of natural resources [13]. In forestry, specific forest management methods have been applied; conservation areas, strict nature reserves or restricted management zones have been established; various restrictions and regulations on cuttings have been enforced. Most of these activities have traditionally been based on the understanding that the best way to protect biological diversity is keeping forests untouched or minimizing any “negative” impact on their natural development.
In an ideal world, nature reserve networks should be designed through a structured and systematic approach using operational criteria and quantitative targets based on the three guiding principles: representativeness, spatial design and site quality. In Europe, most of conservation areas are selected using the full set of criteria, these reserves are typically medium-sized protected areas with no active human intervention, old-growth peculiarities, active natural disturbance regimes and a good ecological integrity [14]. At the same time, protected forest areas are often small, located in majority on land owned by the state, local authorities or other bodies and their management and upkeep is linked with the aims of multiple forest use[20]. In Estonian case, relatively good set of selection criteria has resulted quite balanced network of forest conservation areas. There is optimal size distribution of these areas including large areas where full protection is very efficient, medium size areas with more conservation values and small areas with high conservation values.
There is a high risk that reserve networks will be suboptimal or ineffective when ad hoc site selection is used instead of a structured systematic approach. There are plenty of examples in the scientific literature that show that biodiversity is not adequately protected in forest reserve networks which are not established following standardized selection criteria [14]. Conservation targets can also be missed due to inadequate reserve size, poor quality of the surrounding habitat matrix, or low connectivity between protected sites. As an example, the ability of woodland key habitats to sustain long-term populations of red-listed species in boreal forests has often been questioned because of small size, strong edge effects and isolation of habitat patches [21].
However, reserves alone are not sufficient to preserve forest biodiversity and dynamics in a changing and fragmented world. Even with an expanded reserve system, large areas of land that are managed for silviculture and other human uses should be taken into account through a dynamic conception of biodiversity conservation. It includes the adoption of close-to-nature forestry practices together with conservation measures in the forest matrix to promote resilience and resistance of the ecosystem, site restoration, woodland enlargement and the development of permeable landscapes providing links and stepping stones for species migration [22, 23]. Nature reserves themselves do not secure the preservation of entire biological diversity—the overall management system should be nature-friendly [24]. The Estonian forest policy should secure the productivity of forests and preservation of forest ecosystems at the same time on national level. In managed forests some key elements of old-growth forests should be preserved. So the larger protection areas and nature reserves will act as core areas for species refuge and dispersal and principle “working as a network” is applied to the overall distribution and design of conservation areas.
The flora and fauna of forests has always been changing because of continuous changing of climate and soil conditions, distribution dynamics of species and forest successions. Natural development of forests is characterized by natural disturbances in smaller or larger extent: forest fires, flooding, extensive insect damages etc. Many species groups vitally depend on these natural disturbances that give good possibilities for their life and regeneration. The highest biological diversity occurs in the case of disturbances of average frequency and magnitude; this means that ecosystem has time to regenerate before the next disturbance [1, 25]. There is a need to consider the changeability of nature and to understand the dynamic processes in nature conservation. EFCAN network is not optimally represented by site types and large-area severe forest disturbances. Meso-eutrophic, eutrophic boreo-nemoral and eutrophic paludifying forests should be more conserved and large disturbance areas (wind damage, forest fire) may be also included into the network.
EFCAN inventory found that forests on conservation areas in Estonia are mainly previous commercial forests, including small and fragmented patches of old-growth elements as core areas. In temporal scale such forests will turn slowly to natural forests. The process can take a hundred years or more. In certain cases, nature restoration measures may speed up this process and suit better for overall biodiversity considerations [26]. EFCAN project found several areas where restoration measures may be effective from nature conservation viewpoint.
5. Conclusions
EFCAN project was generally successful. Almost 8% of forest area is strictly protected in 2009. The network of conservation areas is quite well covering all forest ecosystems in Estonia. Several EFCAN selected areas are still not protected for many different reasons. These areas should be considered again for protection as the areas may lose their conservation value. Several forest types (meso-eutrophic, eutrophic boreo-nemoral and eutrophic paludifying forests) should have larger area for conservation and large disturbance areas (wind damage, forest fire) may be also included into the network. The gap between theoretical need and actual conservation is 64,200 ha of these forests. If conservation of such additional areas will succeed, the goals set in the Estonian Forestry Development Programme in 2003 will be met and more than 10% of Estonian forests will have strict protection in a well balanced ecological network.
Acknowledgements
This study was supported by the Estonian Science Foundation and the Estonian Ministry of Environment.
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