Climate and land‐use changes will require species to move large distances following shifts in their suitable habitats, which will frequently involve traversing intensively human‐modified landscapes. ...Practitioners will therefore need to evaluate and act to enhance the degree to which habitat patches scattered throughout the landscape may function as stepping stones facilitating dispersal among otherwise isolated habitat areas. We formulate a new generalized network model of habitat connectivity that accounts for the number of dispersing individuals and for long‐distance dispersal processes across generations. By doing so, we bridge the gap between complex dynamic population models, which are generally too data demanding and hence difficult to apply in practical wide‐scale decision‐making, and simpler static connectivity models that only consider the amount of habitat that can be reached by a single average disperser during its life span. We find that the loss of intermediate and sufficiently large stepping‐stone habitat patches can cause a sharp decline in the distance that can be traversed by species (critical spatial thresholds) that cannot be effectively compensated by other factors previously regarded as crucial for long‐distance dispersal (fat‐tailed dispersal kernels, source population size). We corroborate our findings by showing that our model largely outperforms previous connectivity models in explaining the large‐scale range expansion of a forest bird species, the Black Woodpecker Dryocopus martius, over a 20‐year period. The capacity of species to exploit the opportunities created by networks of stepping‐stone patches largely depends on species‐specific life‐history traits, suggesting that species assemblages traversing fragmented landscapes may be exposed to a spatial filtering process driving long‐term changes in community composition. Synthesis and applications. Previous static connectivity models seriously underestimate the importance of stepping‐stone patches in sustaining rare but crucial dispersal events. We provide a conceptually broader model that shows that stepping stones (i) must be of sufficient size to be of conservation value, (ii) are particularly crucial for the spread of species (either native or invasive) or genotypes over long distances and (iii) can effectively reduce the isolation of the largest habitat blocks in reserves, therefore largely contributing to species persistence across wide spatial and temporal scales.
•Green-tree retention is a black woodpecker nesting habitat in managed forests.•Patches and single trees are used regularly by black woodpeckers for breeding.•Pine is the best black woodpecker ...nesting tree in eastern and northern coniferous forests.•Dead trees are strongly preferred by black woodpeckers for excavating cavities.•Black woodpeckers do well in a landscape mix of old-growth with decaying trees and disturbed forest.
The black woodpecker, Dryocopus martius, a creator of tree cavities, is considered a keystone species and a priority in terms of forest biodiversity conservation. The aim of this paper was to understand how the structure of managed forests impacts the choice of tree for excavating cavities of the black woodpecker. The study was conducted in an extensive forest complex in northeastern Poland dominated by the pine Pinus sylvestris. The parameters of the cavity trees and surrounding forest were analyzed on different levels to determine what trees and stand types were selected by the black woodpecker. In the period from 2018 to 2021, analyses were carried out for 367 cavities excavated in trees growing in forest areas from 0 to 225 years old. The most numerous cavity trees were between 121 and 160 years old. Cavity trees were found in the stands (62%), in the residual forest patches (19%) and in the single trees remaining after logging (19%). Forty-four percent of all cavities were excavated in dead trees. Black woodpecker nesting stands were characterized by lower canopy closures and low understory and shrub layer cover. We did not find a difference between the diameters or the heights of cavity entrances among the black woodpecker nesting trees growing in different habitat types. The black woodpecker is capable of nesting in small fragments of an old stand and even in single old trees growing in clearcut areas. This is due to the high proportion of dead trees in these habitats, which are preferred by woodpeckers for excavating cavities. Leaving patches of old-growth stands in commercial forests positively affects the habitat formation of the black woodpecker and perhaps, as a consequence, that of other animal species that depend on it.
•We tested effect of distance to the forest edge on several bird species.•Frequency of generalist bird species generally peaked close to the forest edge.•Frequency of forest bird species increased ...with the distance from the forest edge.•Effect of tree species composition was significant at the local scale.•Clear-cut areas increase negative effects of forest fragmentation.
Species-rich communities of forest birds generally occupy larger rather than smaller forest fragments. However, the role of distance to the forest edge on the spatial distribution of bird communities within forest fragments remains largely unknown. In this study, we attempted to determine whether and how forest bird species distribution was related to distance from the forest edge or clearing (whichever was closer) taking into consideration effects of fragment size and vegetation. Based on data from a four year bird survey, we explored the spatial distribution of 29 common forest bird species within 24 forest fragments (0.1–255ha) in relation to distance to the forest edge, fragment size and forest vegetation. For this purpose we used generalized additive models (GAMs) with spline components and demonstrated the distance – frequency relationship for each bird species for whom it was relevant. Spatial distribution of the majority of common forest bird species was significantly affected by distance to the forest edge and/or fragment size and vegetation. The maximum frequency of species dependent on distance to the forest edge differed considerably along the line connecting forest edge to the centre of forest fragments. While frequency of the generalist species generally peaked somewhere close to the forest edge, frequency of sensitive forest resident species increased up to a distance of 150m or more from the forest edge. The effect of forest fragment size was consistently accompanied with the effect of distance to the forest edge with the exception of only two generalist species. It appears that a substantial part of the effect traditionally attributed to forest fragment size may be related to distance to the forest edge. Spatial distribution of almost all of the common bird species were further modified by forest vegetation at the local scale, but only rarely by prevalent forest vegetation of the respective forest fragment. Populations of forest resident species, such as Dryocopus martius, may be threatened by management intervention in the forest interior that leads to the forming of “internal” forest edges (e.g. clearcutting). The results documented that forest management based on clear-cut timber harvesting may increase the negative effects of forest fragmentation on distribution of the sensitive forest bird species within forest fragments. This negative effect could be reduced by adoption of timber harvesting methods that avoid the creation of clearings (e.g. single-tree selection), preferably accompanied by exemptions of individuals or patches of old trees from logging.
The black woodpecker Dryocopus martius is an ecologically disproportionately important forest species owing to its abundance. Its large cavities provide breeding sites and shelter for many ...species—large birds, mammals, and social insects. I evaluated the nest tree preferences of black woodpeckers in the Augustów Forest, northeast Poland. Approximately 400 black woodpecker cavities were observed. The Scots pine, Pinus sylvestris, was the most commonly selected tree species, accounting for 90%. The cavity trees were 55–225 years old. All trees younger than 90 years were broadleaved tree species. The trees used to excavate the cavities had a larger diameter at the breast height (DBH) than the average of the stand. The trees selected by black woodpeckers were significantly shorter than the average height of the stands. Over 60% of the cavities were excavated 10–16 m above ground level. I found that the DBH and the first branch height were critical factors affecting the cavity entrance height. In pine-dominated forests, black woodpeckers preferred dead trees. Approximately 44% of new cavities were excavated from dead trees. Leaving dead or dying large trees in commercial forests benefits black woodpeckers and large secondary cavity nesters that depend on it and promotes biodiversity conservation. Birds excavate new cavities at a high rate yearly, in contrast with beech-dominated forests.
Black Woodpeckers Dryocopus martius used small patches of trees as stepping stones when crossing areas of open land during daily movements within their home range in the non-breeding season.
To ...document that Black Woodpeckers, although an obligate forest species, frequently cross areas of open land within their daily home range, using solitary trees or small patches of trees as stepping stones during these movements.
We mounted GPS-loggers on 11 Black Woodpeckers and recorded their position every 5 min for approximately 1 week. Three woodpeckers stayed within continuous forest for the duration of the study, or failed to meet assumptions, and were therefore excluded from the analysis. The remaining eight Black Woodpeckers all moved between discrete woodland units at least once during the study period. Using a habitat use-availability framework, 54 GPS-positions located in gaps of open land between separate forest patches were analysed.
Black Woodpeckers showed a significant preference for trees at low tree availabilities in the open land. However, we could not rule out that their preference for trees was proportional to availability when tree cover was high (> 82% tree cover). The median distance traversed to a location in open land between forest patches was 731 m.
Since the preference for trees was especially pronounced at low tree availabilities, we suggest that Black Woodpeckers use solitary trees or small patches of trees as stepping stones when traversing open areas within their daily home range. We hypothesize that this behaviour lessens the costs of living in a fragmented habitat, and that conservation of trees in open land may contribute to conserving Black Woodpecker populations in areas with fragmented forests.
•We studied the bird communities of Sweden’s protected and production oak forests.•Bird communities in production forests partially overlapped with protected forests.•Vulnerable and near threatened ...bird species occurred in production oak stands.•Production oak stands can complement habitats provided by protected oak forests.•Production oak stands can provide important bird habitats as well as other values.
The oak-dominated woodlands and forests of northern Europe have experienced dramatic declines due to agriculture, urbanization, and conifer-dominated production forestry. These losses have had a substantial negative impact on biodiversity due to the large number of forest species which depend on oak and the environments oak-dominated forests provide. Production oak stands may serve as a means of supplementing or complementing the habitat provided by the limited remaining natural oak remnants in this region. Here we evaluate the extent to which oak plantations in temperate southern Sweden provide habitat and resources for bird communities, by surveying and contrasting the bird species composition and diversity found in mature and young production oak stands (5 and 8 replicates respectively) and protected oak-dominated remnant forests (5 replicates). The mature production stands possessed a bird community partially overlapping in bird species composition, and comparable in species richness (34 species) to that found within protected oak forests (39 species). Furthermore, the production oak forests surveyed hosted threatened or near threatened bird species, including black woodpecker (Dryocopus martius), goldcrest (Regulus regulus), starling (Sturnus vulgaris), and yellowhammer (Emberiza citrinella). Though production oak forests cannot replace the habitat provided by protected oak forests, these stands do appear to provide conditions consistent with the habitat and resource requirements of a diverse cross-section of bird species in this region, including species of substantial conservation concern. Production oak forests thus have the capacity to make a positive contribution to biodiversity conservation, as well as providing a diverse range of goods and services to society.
This systematic survey aimed to acquire knowledge about the foraging behavior of the woodpecker in broad-leaved Korean pine forests,and explore the coexisting features of sympatric woodpecker ...species,by investigating the foraging habitat and behavior characteristics of three woodpecker species. The species were black woodpeckers( Dryocopus martius),three-toed woodpeckers( Picoides tridactylus),and the great spotted woodpecker( Dendrocopos major) that are distributed in Liangshui nature reserve in the northeastern region of China. The survey was conducted from January 5 to 13,2016 and45 east-west direction parallel transects were set in the core area of the reserve,each with a length 1 km and each transect was surveyed two times. Furthermore,25 and 20 transects were surveyed in the morning and afternoon,respectively. Except for the species and sex of the woodpeckers,15 variables of the forage habitat and behavioral characteristics were measured,which were forest type,slope position,dominant tree species,crown
Given their importance as a resource for many forest organisms, tree cavities were inventoried in the managed pine forests of north-east Poland, in relation to the: 70â100, 101â130 and >130 year ...age-classes within the clear-cutting system. The densities at which cavities were present was found to depend on forest age, given that stands 70â100 years old were characterised by an average density of 0.62 trees ha, while forests older than 130 years reported 3.28 trees ha. Stands aged 70â100 years differed from those aged 130+ in having just 0.27 trees ha of cavity trees, as compared with 2.91 trees ha. The total volume of cavity trees in stands up to 100 years old was 0.37 mhaon average, as compared with 5.42 mha in stands over 130 years old. The cavities created by woodpeckers constituted 76% of all of those found, and included 53% excavated by great spotted woodpeckers ( L.) and 23% by black woodpeckers (L.) The proportion of cavities excavated by was highest in the youngest age class of stands. There, cavities made by constituted only 8% of the total, as compared with 31% in the oldest stands. The abundance of cavity trees thus differed along an age gradient, though in any event the availability of cavity trees appears to be too limited to provide for the needs of hole-nesting birds. Forest managers must thus take more account than hitherto of the need to protect cavity trees.
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•Species distribution may depend on availability of functionally different habitats.•We model black woodpecker distribution considering feeding and nesting habitats.•Feeding and nesting habitats show ...different pattern of occurrence and availability.•Feeding habitat is the main limiting factors for the species in the area.•Habitat management for conservation should focus on feeding habitat.
Most modelling exercises use generic occurrence points of a species, but the distribution of habitats used for different purposes may differ. Modelling separately the availability of functionally different habitats may allow for the identification of the habitats mostly affecting/limiting distribution, with important implications for conservation. We analyzed the regional distribution of the black woodpecker in Northern Italy. We separately modelled the availability of feeding and nesting habitats at the fine scale (20m×20m), and compared the outputs with a more conventional distribution modelling procedure, which included all records and was developed at the territory scale (1km×1km). Both the conventional and feeding habitat models performed well (although they tended to under- and overestimate occurrence, respectively), whereas the nesting habitat model had a lower discriminatory ability. Nesting and feeding habitats show different relationships between woodpecker occurrence and habitat variables, this resulting in a weak overlap of the respective niches and in quite different distributions. The conventional model provided less information for management, being mainly affected by elevation and urbanized areas; the two specific models instead showed effects of habitat variables on occurrence of feeding and nesting sites. The availability of feeding habitat is likely the most important factor limiting distribution in the area and could be the focus of possible habitat management, which should include the preservation of grassland patches interspersed within woodlands, especially on South-facing, gently sloping mountainsides. Modelling separately the availability of functionally different habitats may provide useful information for conservation and management.
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