•Snags height, deadwood thickness and species composition are features strongly varied in forest ecosystems.•Deadwood position and decay stages are less varied.•Deadwood diversity depends on many ...features of habitats and stands.•Deadwood diversity is positively related to the amount of deadwood.•The species composition of stands and the fertility of habitats have a strong influence on deadwood diversity.
Deadwood (DW) is a crucial component of habitats, with both its volume and diversity considered critical for saproxylic organisms. Deadwood position, thickness, snag height, species composition, and decay stage were studied in the context of eight factors characterizing habitats, stands, and management types. A multivariate multiple regression model was used to analyze data from 29,098 sample plots.
Deadwood diversity (a 5-dimensional dependent variable) was found to strongly depend on DW volume in a given area and on the species composition of the stand. A less pronounced effect was exerted by site fertility and moisture, the age and DBH structure of the stand, and terrain type. The model also revealed that the location of the stand in managed or unmanaged areas did not have a direct impact on deadwood diversity, with stand features being more important.
Analysis of individual qualitative characteristics showed that DW thickness was affected by the same seven factors as DW diversity. DW position and decay stage were influenced by four factors: site fertility and moisture as well as stand age and species composition. In addition to the species composition of stands, DW species composition was positively influenced by more fertile and moist sites and a more varied DBH structure of stands. A significant negative effect was identified for high DW volume, which indicates that the deadwood accumulated in a stand tends to be derived from the tree species that was most vulnerable to mortality at a given time. Snag height variation was influenced by such stand characteristics as age, DBH structure, and species composition; the other significant factors were DW volume and terrain type. The diversity levels of individual DW characteristics were significantly and positively correlated, which means that all of them often revealed high or low diversity at the same time.
Our study showed that forests with low DW volume additionally face the problem of DW quality. Thus, efforts to increase DW volume should be focused on those DW characteristics that are lacking (large trees, species diversity, and height variation of snags). DW diversity is lower in younger stands, with little DBH variation, and in forests which are more easily accessible, located mostly in the lowlands, and growing on less fertile and dry or mesic sites.
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•Deadwood volume in protected areas depends on random factors and is difficult to predict.•Deadwood accumulation depends on the vigor of the species comprising the stand.•Silvicultural treatments ...considerably reduce the effects of natural factors.•Deadwood volume increases with site fertility and stand age.•Terrain-related difficulties hindering silvicultural treatments have a positive effect on the amount of deadwood.
In forest management policy, deadwood is regarded as an indicator of sustainable forest management. Dead trees are a key habitat feature for a wide range of organisms. In this study, data from a regular network of nearly 30,000 sample plots (the National Forest Inventory) distributed throughout Poland were used to determine relationships between deadwood volume and thirteen selected natural and human-related factors: forest ownership, protection type, inclusion in the Natura 2000 network, terrain, slope gradient, site fertility, site moisture (water abundance), dominant species, age of the dominant species, stand volume, tree and shrub density, sapling and shrub cover, and stand damage. Analysis of data on deadwood volume was carried out in two steps: univariate analysis was used to determine present-day differences among forests, while a logistic regression model was applied to identify the factors that had the greatest impact on deadwood volume variability on the studied plots. Despite interference from numerous random effects that are difficult to capture and quantify, being often associated with disturbances and differences between the silvicultural approaches of individual forest managers, many of the analyzed factors were found to exert a significant influence. Strong relationships were identified mostly in managed forests (private, municipality-owned, and those managed by the State Forests National Forest Holding). In national parks and nature reserves, the identified effects were less pronounced due to the fact that the examined plots differed in terms of protection type and duration and may have been impacted by different natural disturbances. Indeed, deadwood volume was significantly affected by protection type, with much more deadwood found in strictly protected areas as compared to forests under active protection. Inclusion in Natura 2000 had only a slight effect. On the other hand, a major role was played by difficult terrain accessibility, which impeded silvicultural treatments. More deadwood occurred in the mountains, with increasing slope gradient positively affecting deadwood volume, but only up to a certain point. On the steepest slopes deadwood volume decreased due to the soil and wood sliding to a lower level. Deadwood volume was significantly greater on more fertile and moist sites. In managed forests, both stand age and growing stock volume were positively associated with deadwood accumulation. The species composition of stands, mostly attributable to habitat conditions, was also relevant. The present work identified some significant differences in deadwood volume between stands, and the findings may be useful in developing future management practices with a view to supporting biodiversity.
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Abstract
Numerous bird species, often rare or endangered, rely on the presence of standing and downed deadwood for shelter, nesting, and foraging. Habitat quality was evaluated on the basis of ...deadwood volume, the density of large standing deadwood, and the space filling index (SFI). The SFI reflects the degree of space filling of the bottom layers taking into account tree trunks, seedlings, saplings, ground vegetation, stumps, and downed deadwood. Analysis encompassed all special protection areas (SPAs) in Poland (a total of 107 SPAs containing 7974 sample plots monitored under the National Forest Inventory). An additional in-depth analysis was conducted for 30 SPAs with the greatest share of forest habitats. The studied indicators varied substantially both between and within individual SPAs, with deadwood volume ranging from 1.3 to 50.5 m
3
ha
−1
(mean of 9.0 m
3
ha
−1
) and the density of large standing deadwood (diameter at breast height ≥ 30 cm) from 0.1 to 16.0 ind ha
−1
(mean of 2.2 ind ha
−1
). These values were relatively low compared to the density of living trees with corresponding dimensions (111 ind ha
−1
). SFI analysis indicated high or very high space filling of the bottom forest layers on 14–56% of sample plots in a given SPA. The presence of deadwood was found to be significantly positively affected by SPA location in the mountains, a greater proportion of sites with higher fertility, a greater share of forest area under strict protection, as well as higher stand volume within a given SPA. The correlation between deadwood volume and the density of birds (primary and secondary cavity nesters) in individual SPAs was positive (
R
= 0.60). As compared to lowland areas, SPAs in mountain areas are generally characterized by high stand volumes, a greater density of large living trees, and a greater amount of diverse deadwood. In those areas conservation measures should involve continuous monitoring and diagnosing of any problems associated with the populations of individual bird species; focused efforts should be implemented to support those species that exhibit unfavorable population trends. In most lowland SPAs measures aimed at the improvement of site conditions for birds must be more extensive than in the mountains, with a low abundance of dead trees (especially large ones). These parameters can be improved by retaining some senescent stands in managed forests until their natural death and implementing a strict protection regime in areas of high conservation value.
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Saproxylic species from different taxonomic groups often occur only on certain types of deadwood with specific qualitative characteristics. The various types of deadwood are very dynamic elements of ...forest ecosystems, associated with many site and stand features, as well as with the type of forest management. Using a pool of 29,098 sample plots spread across Poland, we analyzed 30 different deadwood types defined on the basis of three characteristics: position (standing, lying), degree of decomposition, and size. Statistical hurdle models were used to assess changes in the volume of individual deadwood types based on a broad range of independent variables. Depending on the type of management, terrain, site fertility, stand volume, tree density, and stand age, the models revealed substantial differences in the volume of different deadwood types, ranging from 0 to approx. 4 m3 ha−1. It was found that the volume of most deadwood types (except for a few, mostly with diameters under 15 cm) increases with stand age or stand volume. In managed forests at all stages of stand development there is a deficiency of thick deadwood. Both standing and lying deadwood at different decay stages is available continuously, irrespective of the values of individual independent variables, but considerable differences exist. While most lying deadwood exhibits higher levels of decomposition, in standing deadwood the proportions of different decay stages are strongly associated with tree diameter at breast height. The developed models make it possible to predict the volume of individual deadwood types for a broad range of independent variables. The current work presents several examples, with the results showing extremely complex relationships between deadwood diversity and site and stand features at every stage of forest development, with continuous changes in the volume and proportions of different deadwood types. In general, at the landscape level Polish forests contain both standing and lying deadwood at all decay stages in more or less equal proportions. However, in forest management one should pay special attention to the dimensions of retained deadwood. The absence of thick deadwood is particularly conspicuous in lowland managed forests.
•The total deadwood volume consists of many deadwood types with very different characteristics.•Statistical models based on stand features describe the diversity of dead wood with high accuracy.•The diversity of the deadwood changes with the age of the stand, the method of management and habitat conditions.•Some types of deadwood are not found in all forests, especially thick deadwood is completely removed.•Management of deadwood resources should be largely based on its diversity.
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Standing and downed deadwood at different stages of decay provides a crucial habitat for a wide range of organisms. It is particularly abundant in unmanaged forests, such as strictly protected areas ...of national parks and nature reserves. The present work used the available data for such sites in Poland, analyzing a total of 113 studies concerning 79 sites to determine the causes contributing to variation in deadwood volume based on the duration of conservation, changes in deadwood volume over time (for those sites which were examined multiple times), elevation above sea level, forest type, stage of forest development, input of dead trees from the years preceding deadwood measurements, live tree volume, and the proportion of downed to standing deadwood). Depending on species composition and site altitude, most tree stands fell into one of four categories: subalpine spruce forests, montane beech-fir forests, low altitude beech-fir forests, or oak-hornbeam and riparian forests. The mean deadwood volume for all forest types amounted to 172.0 m
3
/ha. The mean volume of deadwood in montane beech-fir forests (223.9 m
3
/ha) was statistically significantly greater than in the other three forest types, for which it ranged from 103.5 to 142.5 m
3
/ha. A direct effect of the duration of conservation on deadwood volume was not identified. Nevertheless, analysis of repeated measurements on the same sample plots at 10-year intervals showed a consistent rise in mean deadwood volume. A linear regression model for all the analyzed factors reported from montane beech-fir forests and subalpine spruce forests showed that in addition to site altitude, another statistically significant variable was the input of dead trees (
R
2
= 63.54%).
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•Bird breeding communities vary greatly depending on the characteristics of the gardens.•The features of the gardens determine the even or uneven distribution of bird species.•The function of gardens ...as food sources increased from spring to winter.•Some gardens only provide a nesting place for birds, there are no places suitable for foraging.•It is necessary to compensate for some lost features of gardens in order to preserve bird species.
Demographic data show booming metropolitan populations and the related rapid spread of urbanized areas. Cities already harbor numerous diverse habitats, including gardens, varying greatly both in terms of floristics and architectural attributes. The way gardens are designed and managed is of crucial importance for the birds associated with them. The present work provides a comprehensive overview of garden features, which were used in cluster analysis to distinguish several garden types. The birds occurring in gardens located on the outskirts of the city in southern Poland were analyzed in three phenological periods (breeding season, autumn, winter).
Depending on garden type, bird density ranged from 10.8 to 57.4 breeding pairs per ha, with 0.8–8.3 species per garden. The species similarity Jaccard index of bird assemblages was from 0.10 to 0.75. The evenness index revealed some garden types with very even species distributions, as well as some types that were strongly dominated by a single species. Garden features also affected proportions between groups of species with different nesting preferences (cavity nesters, canopy nesters, birds nesting in building, and those nesting in shrubs and near the ground). The function of gardens as food sources increased from spring to winter. The garden attributes that significantly affected the occurrence of breeding birds were high tree density and hedges, building walls and attics available for birds, as well the presence of chicken coops. In terms of feeding, of importance was not only lush vegetation, but also places where different types of food were provided for birds, poultry, and domestic and farm animals.
As the unfolding changes in urban and suburban areas are likely to result in the disappearance of some garden features and the associated niches, it will be necessary to compensate for them with a view to conserving bird species such as the house sparrow. To that end, appropriate educational and advisory programs should be offered to garden owners.
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The continuing decline in biodiversity presents a major environmental protection challenge. The conservation of sufficiently extensive and diverse habitats requires an array of coordinated actions, ...often involving large areas. While a set of conservation objectives have been defined for the Natura 2000 network, no universal methods of accomplishing them have been specified, and so they must be designed by individual Member States. Deadwood volume and the density of large deadwood pieces are widely used for evaluating the quality of forest habitat types designated under the Habitats Directive. In the present study, data from 5557 sample plots were used to evaluate the mean values of the two deadwood indicators as well as the ratio of deadwood volume to living tree volume for each of the 13 habitat types in Poland. In addition, a logistic regression model was constructed to evaluate the effects of terrain, site, and tree stand characteristics as well as protection type on deadwood volume in Natura 2000 areas. Mean deadwood volume varied greatly between habitat types, with the lowest values found for Central European lichen Scots pine forests (91T0–2.5 m3 ha−1) and Old acidophilous oak woods (9190–4.4 m3 ha−1), and the highest for Riparian mixed forests (91F0–43.1 m3 ha−1) and Acidophilous Picea forests of the montane to alpine levels (9410–55.4 m3 ha−1). The ratio of deadwood volume to living tree volume ranged from approx. 1%–17%. Additionally, the presence of large deadwood differed among habitat types: in some, there were no deadwood pieces with a diameter of ≥50 cm, while their maximum density was 6.1 pieces ha−1. The logistic regression model showed that the likelihood of a habitat type to have a ‘favorable conservation status’ as defined by deadwood abundance (a threshold of at least 20 m3 ha−1 according to Polish manuals on habitat type evaluation) increased with sample plot elevation, site fertility, and moisture, as well as stand age and volume. Positive effects were also observed for forests under strict and active protection versus managed forests. Planned efforts are necessary to enhance the quality of habitats with insufficient deadwood, especially in managed forests. Special attention should be given to areas that are readily accessible due to gentle terrain and low site moisture. Furthermore, younger stands on less fertile sites may require intervention to promote deadwood accumulation. We recommend retaining a certain proportion of mature stands until natural death and decomposition. Increasing the density of large deadwood is currently one of the most pressing conservation needs in most habitat types.
•Data on the characteristics of tree stands as well as the birds inhabiting them were collected from a subalpine spruce forest.•The study area exhibited development properties resulting from both ...biotic and abiotic factors.•Tree stands were characterized in terms of the tree layer, saplings, and deadwood.•The data included bird species composition and pair density in the breeding season or individual bird density in the nonbreeding season.
The paper presents data on tree stands located in a subalpine spruce forest in the Gorce National Park (Western Carpathians, Poland) as well as on the birds inhabiting them in the breeding and nonbreeding seasons. The authors conducted stand measurements on a total of twenty-four sample plots, with eight plots established in each of the three studied forest development stages (mature, break-up, and growing-up) representing successive phases of subalpine forest development. The study area designated for each stage was 30 ha. The development properties of each study area resulted from both biotic and abiotic factors. Tree stands were characterized in terms of the tree layer, saplings, and deadwood. The types of deadwood measured were: standing entire dead trees, snags, stumps, and downed deadwood. In the case of birds, the presented data include species composition and pair density in the breeding season and individual bird density in the nonbreeding season. The authors used these data in a paper 1 examining the relationship between forest structural indicators and bird diversity in the three forest development stages. Other researchers can also utilize these data for the purpose of comparison with other areas representing similar forest communities or for studies on stand dynamics, especially in the face of climate change which may substantially affect those phenomena. Furthermore, the presented data may be useful in studies concerning the abundance and dynamics of bird assemblages and other organisms associated with the subalpine zone as well as in research devoted to the diversity of ecological niches. Such investigations may lay foundations for developing conservation guidelines for the ecosystems in question.
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► Owing to extensive development of roads, millions of animals are killed annually. ► We compared roadkilled three bird species to those killed by predators. ► Study species were in better body ...condition than those killed by raptors. ► Weaker individuals are not more vulnerable on the road. ► Future road construction and regulations must take wildlife into consideration..
Owing to the extensive development of road networks, millions of animals are killed annually. This impact on the natural environment has been questioned: is there a selection of victims in the car collisions? and do road-kills, as do predators, influence a population by eliminating individuals in poor condition? We compared road-killed individuals to those killed by predators in SE Poland in three bird species: Yellowhammer
Emberiza citrinella, Barn Swallow
Hirundo rustica, and Chaffinch
Fringilla coelebs. We applied ptilochronology, in which the width of feather growth bars represents an individual’s relative nutritional condition. Our results show that the analyzed species were in significantly better body condition than those killed by raptors. Our study does not concur with previous studies which concluded that weaker individuals are more vulnerable on the road. Raptors select prey in poor condition, but road-killed individuals are in significantly better condition, so apparently road-kill results in the random elimination of healthy individuals. The conservation implications of this study are far-reaching; future road construction and safety regulations must take wildlife into consideration. If these human-created habitats are killing a significant proportion of the healthier part of natural populations in a non-selective manner, this could result in situations where fragmented populations could be driven to a critical stage, and/or the situation of declining or endangered populations worsened further.
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This study analyzed the effects of various forest management scenarios on habitats of the black stork, which has very specific requirements: it needs extensive forest complexes with a significant ...proportion of old trees for nesting, and bodies of water for foraging. The relationship between different forest management scenarios and the presence of black storks was examined in a large forest complex (9641 ha of managed stands) surrounded by wetland areas. A simulation of forest development under three management regimes was performed for eighteen 10-year periods. Management scenarios differed in terms of the species composition of stands, rotation age, retention tree areas, and silvicultural treatments. The basic scenario was characterized by a species composition consistent with natural-type stands, but with higher proportions of Scots pine and oak, with rotation ages of 100 and 140 years, respectively, managed by the shelterwood system. The productive scenario featured monospecific stands with a dominance of Scots pine with a rotation age of 90 years, harvested by clearcutting. Finally, the long rotation scenario introduced mixed tree stands with a long rotation age (110 and 180 years for Scots pine and oak, respectively). As compared to the basic scenario, the total harvest volume was greater by 14.6% in the productive scenario and smaller by 16.2% in the long rotation scenario. The availability of habitats for black stork changed as a result of different species compositions and age structures of tree stands. A considerable decrease in rotation age (below 100 years) and the elimination of oak trees from stands in the productive scenario adversely affected potential habitats for black stork. On the other hand, the factors favorable to black stork habitats were a long rotation age, the presence of oak in stands, the application of shelterwood cutting, and the use of retention trees in the long rotation scenario. This scenario would probably also benefit other bird species legally protected under the European Union’s Birds Directive.
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