The policy term green infrastructure highlights the need to maintain functional ecosystems as a foundation for sustainable societies. Because forests are the main natural ecosystems in Europe, it is crucial to understand the extent to which forest landscape management delivers functional green infrastructures. We used the steep west–east gradient in forest landscape history, land ownership, and political culture within northern Europe's Baltic Sea Region to assess regional profiles of benefits delivered by forest landscapes. The aim was to support policy‐makers and planners with evidence‐based knowledge about the current conditions for effective wood production and biodiversity conservation. We developed and modeled four regional‐level indicators for sustained yield wood production and four for biodiversity conservation using public spatial data. The western case study regions in Sweden and Latvia had high forest management intensity with balanced forest losses and gains which was spatially correlated, thus indicating an even stand age class distribution at the local scale and therefore long‐term sustained yields. In contrast, the eastern case study regions in Belarus and Russia showed spatial segregation of areas with forest losses and gains. Regarding biodiversity conservation indicators, the west–east gradient was reversed. In the Russian, Belarusian, and Latvian case study regions, tree species composition was more natural than in Sweden, and the size of contiguous areas without forest loss was larger. In all four case study regions, 54–85% of the total land base consisted of forest cover, which is above critical fragmentation thresholds for forest landscape fragmentation. The results show that green infrastructures for wood production and biodiversity conservation are inversely related among the four case study regions, and thus rival. While restoration for biodiversity conservation is needed in the west, intensified use of wood and biomass is possible in the east. However, a cautious approach should be applied because intensification of wood production threatens biodiversity. We discuss the barriers and bridges for spatial planning in countries with different types of land ownership and political cultures and stress the need for a landscape approach based on evidence‐based collaborative learning processes that include both different academic disciplines and stakeholders that represent different sectors and levels of governance.
Modern pollen composition obtained from waterbody surface sediment represents surrounding vegetation and landscape features. A lack of detailed information on modern pollen from Latvia potentially limits the strength of various pollen-based reconstructions (vegetation composition, climate, landscape, human impact) for this territory. The aim of this study is to compare how modern pollen from natural and human-made waterbodies reflects the actual vegetation composition and landscape characteristics. Modern pollen analyses from surface sediment samples of 36 waterbodies from Latvia alongside oceanic-continental, lowland-upland, urban-rural and forested-agricultural gradients have been studied. In addition, we considered the dominant Quaternary sediment, soil type and land use around the studied waterbodies in buffer zones with widths of one and four km. The information on climate for the last 30 years from the closest meteorological station for each study site was obtained. Data were analyzed using Pearson correlation and principal component analysis. Results show that relative pollen values from surface sediment of waterbodies reflect dominant vegetation type and land use. Modern forest biomass had a positive correlation with pollen accumulation rate, indicating the potential use of pollen-based forest biomass reconstructions for the boreonemoral zone after additional research and calibration.
Wildfires as natural disturbances have had important impacts on terrestrial ecosystems, including forests. We studied patterns of short-term vegetation recovery after surface fire in protected hemiboreal Pinus sylvestris L.-dominated forest. Our study was carried out near Stikli village in Western Latvia. Seven forest stands – middle-age and over-mature were sampled on nutrient-poor and mesic soils. Forest fire occurred in the summer of 2018 and covered 1440 ha of forested area. In each stand we established 16 sample plots (1 m × 1 m) in a radial pattern from the center. Every summer from 2019 till 2022 we surveyed these sample plots – recorded projective cover (%) and identified Ellenberg indicator values and species traits – plant strategy groups (C-S-R after Grime), Raunkiær life history forms and habitat types. Additionally, the occurrence of specialized fire-adapted plants was recorded. In total we identified 15 species in the ground layer, 47 species in the herbaceous layer, and 9 regenerating tree species. The colonization at the ground layer was the most rapid (projective cover increased overall by 67% in middle-aged stands and by 82% in over-mature stands). Species diversity was the highest at the herb layer during the third (middle-aged stands) and fourth (over-mature stands) after fire disturbance but showed overall declining trends. Betula spp. and Populus tremula L.-dominated regenerating tree species. The dominance of fire-adapted species declined rapidly after the fire except for moss Polytrichum spp. Overall, hemiboreal over-mature stands demonstrated higher vegetation cover and more rapid rate of initial colonization compared to middle-aged stands.
To increase set-aside areas and protect biodiversity values in managed hemiboreal forest landscapes, small forest parcels called Woodland Key Habitats have been designated in Baltic and Nordic countries. The aim of this study was to investigate the persisting influence of the edge on vegetation dynamics for young, medium-old and old edges in Alnus glutinosa (L.) Gaertn. Woodland Key Habitats. All of these edges are adjacent to recently disturbed (clear-cut) stands. We surveyed edge influence on vegetation in bryophyte, herbaceous, shrub and tree layers in 90 plots in 30 set-aside forest stands in Southern Latvia. We tested the differences in the number of species and projective coverage in all vegetation layers, but plant functional types were examined—separately in the herbaceous layer. We found that edge influence in protected forest stands of A. glutinosa swamp forests reflects strong changes in vegetation and plant functional types in the herbaceous layer mostly up to 20 years after clear-cut disturbance in adjacent stands. The greatest differences were between young edges (≤20 years) and old edges (≥41 years), but there were very few significant differences between medium-old (21–40 years) and old edges which signifies more rapid changes in the early stages of edge influence and gradual stabilization of vegetation later on. We found that in edges adjacent to recently disturbed stands (up to 20 years), significantly less rare and indicator epiphytic lichen species occur, but this occurrence increases over time and edge influence is no longer present beyond 20 years after disturbance. Changes in vegetation and species occurrence found in our study indicated the need to plan the allocation of set-aside patches in production forest landscapes to ensure connectivity over longer period of time. Careful planning of clear-cuts in neighboring areas over time can significantly reduce the impact of edge effect on these set-asides.
31 August 2019 in iForest - Biogeosciences and Forestry
Most of the forest area dominated by pedunculate oak (Quercus robur L.) in Latvia was lost to arable land several centuries ago and the remnant patches of Q. robur stands are small and spatially scattered. We hypothesized that a large part of the present Q. robur stands in the Eastern Baltic area of the hemiboreal forest zone developed around the past manor houses in the period of social and political turmoil and subsequent agricultural land abandonment. Our aim was to determine the relationship of Q. robur stand occurrence with soil properties, climatic conditions and proximity to past manor houses. Our study area was the entire territory of Latvia (64.589 km2), divided into 16 landscape regions. We used the State Forest Inventory database to filter out all stands dominated by Q. robur (n=3746). Spatial aggregation of the stands was tested by multi-distance spatial clustering analysis (Ripley’s K method). Mean stand area and Euclidean nearest-neighbour distance for stands were calculated for landscape regions. Binary logistic regression with the calculation of autocovariates showed that winter temperature, soil texture, carbonate concentration and distance to closest manor house were the independent factors significantly (p<0.01) related to the probability of occurrence of Q. robur stands. The results showed that Q. robur is spatially clustered, i.e., significantly different from a random distribution (p<0.05). Higher densities of stands occurred in landscape regions with milder maritime climatic conditions. The largest proportional area of stands established between 1885 and 1914 in the period when peasants gained title to lands and manor lords lost control over their land holdings. In addition, in the landscape regions of Rietumkursa, Austrumkursa and Rietumzemgale, the abundance of Q. robur stands coincided with high densities of past manor houses. Thus, establishment of the Q. robur stands likely responded to suitable conditions (open canopy) made available for tree colonization during the land reform occurred 100 years ago. Our results suggest that priority for conservation should be given to spatial aggregations of stands with high connectivity and on richer soils in more maritime conditions.