Clear-cut Forest Research Articles

Robust predictive performance of indicator species despite different co-occurrence patterns of birds in natural and managed boreal forests

Indicator species are widely used biodiversity surrogates that allow the assessment of biodiversity without the expensive and time-consuming construction of species inventories. The selection of indicator species often relies on species co-occurrence patterns, which may be altered by anthropogenic disturbance such as forest harvesting, imposing a unique challenge to their application in managed forest. Here, we studied boreal bird communities in natural forests originating from wildfire and managed forests originating from clearcutting. We aimed to (1) compare species co-occurrence patterns in natural and clearcut forest stands, (2) select indicator species based on species co-occurrence patterns to predict avian diversity, and (3) evaluate the predictive performance of indicator species under both natural and clearcutting disturbance regimes using the same training data set and an independent testing data set. We found that species co-occurrence patterns differ substantially between natural and clearcut stands, suggesting that forest harvesting alters species-environment relationships and/or interspecific interactions. Consequently, we selected different sets of species as indicators of avian diversity based on data from natural or clearcut stands. However, according to internal and external evaluation, selecting indicator species using data from both natural and clearcut stands produced surrogates that predicted avian diversity accurately and precisely in both types of forests. Our results suggest that, despite forest harvesting altering species co-occurrence patterns, a comprehensive understanding of species co-occurrence patterns across natural and managed forests can be used to develop robust biodiversity surrogates. Our study shows that small sets of indicator species can represent the biodiversity of a wide range of species in ecosystems undergoing anthropogenic disturbance, which has important implications for the application of biodiversity surrogates for conservation.

Consequences of bioenergy wood extraction for landscape-level availability of habitat for dead wood-dependent organisms

Stumps and slash resulting from forest clearcutting is used as a source of low-net-carbon energy, but there are concerns about the consequences of biofuel extraction on biodiversity. Logging residues constitute potentially important habitats, since a large part of forest biodiversity is dependent on dead wood. Here we used snapshot field data from a managed forest landscape (25 000 ha) to predict landscape scale population changes of dead wood dependent organisms after extraction of stumps and slash after clearcutting. We did this by estimating habitat availability for all observed dead wood-dependent beetles, macrofungi, and lichens (380 species) in the whole landscape. We found that 53% of species occurred in slash or stumps. For most species, population declines after moderate extraction (≤30%) were small (<10% decline) because they mainly occur on other dead wood types. However, some species were only recorded in slash and stumps. Red listed species were affected by slash and stump extraction (12 species), but less often than other species. Beetles and fungi were more affected by stump extraction, while lichens were more affected by slash extraction. For beetles and lichens, extraction of a combination of spruce, pine and birch resulted in larger negative effects than if only extracting spruce, while for fungi tree species had little effect. We conclude that extensive extraction decreases the amount of habitat to such extent that it may have negative consequences on species persistence at the landscape level. The negative consequences can be limited by extracting only slash, or only logging residues from spruce stands.

Effect of forest clear cuts on plant–pollinator interactions: the case of three ericaceous subshrubs in Lithuanian pine forests

Managed boreal pine forests are subject to regular clear cuts causing significant disturbances to these ecosystems. It is believed that, to some extent, they resemble natural cycles of forest growth, decline, and regeneration and can benefit, e.g., mutualistic relations among plants and pollinators. To study the impact of forest management (clear cuts) on pollinator visitation, we focused on three ericaceous plant species, &lt;em&gt;Vaccinium myrtillus&lt;/em&gt;, &lt;em&gt;V. vitis-idaea&lt;/em&gt;, and &lt;em&gt;Calluna vulgaris&lt;/em&gt;, common elements of pine forest understory. Our observations, conducted in Lithuania, showed that there are no differences among control mature stands and clear cut areas in terms of visitation frequency for all three studied species. However, at least for &lt;em&gt;C. vulgaris&lt;/em&gt;, a shift toward fly visits was observed in the clear cut site, showing that open areas are preferred habitats for these insects. Ants constituted an important share of visitors to flowers of &lt;em&gt;V. myrtillus&lt;/em&gt; and &lt;em&gt;C. vulgaris&lt;/em&gt;, suggesting their important role in reproduction of these plant species.

Timing of Breeding in an Ecologically Trapped Bird.

In human-modified environments, organisms may prefer to use habitats where their reproductive performance is lower compared to alternative options. Many such ecological traps occur in seasonally changing environments. Although the timing of breeding has been shown to impact reproductive performance in a variety of organisms, it has never been considered as a potential mechanism underlying ecological traps. We address this issue with a migratory bird, the red-backed shrike, breeding in a human-modified, farmland-forest landscape. Shrikes prefer breeding in forest clear-cuts where their reproductive performance is lower than in less attractive farmland. We compared brood size and quality of early (first broods) and delayed breeders (replacement broods) between the two habitats. We found a stronger seasonal decrease in reproductive performance in preferred forest clear-cuts than in farmland. Food resources were slightly more abundant in forest than in farmland at the beginning of the season but depleted more steeply in forest by the end of the breeding season. By contrast, the phenotypic quality of breeders did not decline over the course of the season in either habitat. This is the first report that the timing of breeding relative to the seasonal change in key resources may play a significant role in explaining low reproductive performance in ecological traps.

Assessment of Soil Fertility Changes Over 7 Years after Strip Clearcutting and Afforestation ina Low-Quality Forest Stand in China

In order to change the low-quality forest stands into qualified forest stands with desirable productivity and other ecological benefits, it is necessary to adjust the stand structure and functions. In this study, a low-quality forest stand after strip clearcutting in the Lesser Khingan Range of China was investigated, and the principal component analysis and membership functions were combined to evaluate the integrated soil fertility in different experimental strips (horizontal strips: S1-6 m×100 m, S2-8 m×100 m, S3-10 m×100 m, S4- 15m×100 m; Vertical strips: H1-6 m×100 m, H2-8 m×100 m, H3-10m×100 m, H4-15 m×100 m). Results showed that most soil fertility indexes of the experimental strips showed moderate variation over time, the variation coefficient of soil pH was relatively smaller, and that of total phosphorus was the largest. The integrated soil fertility index (IFI) of different strips generally decreased at the initial period and then increased over time with the lowest value appeared after planting for 3 years. After afforestation for 7 years, the order of the IFI for the horizontal clearcutting strips is: S2>S3>S4>S1, while thatof the vertical clearcutting strips is H1>H2>H4>H3. The integrated soil fertility index of S2 was the highest, which was also significantly higher than that of the year of harvest, showing the best effect. The soil fertility of some experimental strips (S2, S3, H1) was improved, however most of the clearcutting strips were remained at moderate level. Compared to vertical strips, the horizontal clearcutting strips showed better improvement in soil fertility. It is recommended that the 8 m×100 m horizontal clearcutting strip can be applied in forestry practice due to the significant improvement in soil fertility. However, soil fertility change is a long-term process, therefore long-term and consecutive observation in combination with scientific and effective study methods is still needed in order to accurately assess the changes of soil fertility in the clearcutting strips.

Recovery of surface-dwelling assemblages (Coleoptera: Carabidae, Staphylinidae) during clear-cut originated reforestation with native tree species

Background and purpose: Timber-oriented forest management has an important impact on biodiversity in forest ecosystems. Recovery dynamics of two groups of beetles (Coleoptera: Carabidae, Staphylinidae) were studied after reforestation with native English oak ( Quercus robur ). We expected that reforestation with heavy site preparation causes a shift in the diversity of surface-dwelling beetles in early phases of reforestation. Moreover, we tested the habitat specialist hypothesis, assuming that diversity of forest specialist species will be lower in early phases with open canopy than later phases of reforestation after the canopy closure. Materials and methods: We compared litter sifter samples among mature (130-year-old) oak forest, and recently established (5-year-old), young (15-year-old), middle-aged (45-year-old) reforestations. Results: Our results showed that diversity of ground beetles was the highest in the recently established reforestation, while it was the lowest in the mature oak forest. Contrarily, diversity of rove beetles was the lowest in recently established reforestation and it was the highest in the mature oak forest. In agreement with the habitat specialist hypothesis, the diversity of forest specialists of both taxa was lower in the recently established reforestation than in the young and middle-aged reforestations as well as mature forest. Discussion: Our results suggested that clear-cutting of mature forest, site preparation before reforestation and cultivation by light tilling in early phases of reforestation have detrimental effects on forest specialist rove beetles and ground beetles. However, reforestation with native species could be a feasible management method in pannonic mesophile sand steppe, because forest specialist species can recover after the canopy closure.

Forest clear-cuts as additional habitat for breeding farmland birds in crisis

Forest clear-cuts may offer suitable habitats for farmland birds, however empirical evidence on the effect of clear-cut size, age and distance from farmland habitats is largely lacking. In this study we investigated local (alpha) and total (gamma) diversity of farmland birds in 137 clear-cuts in a large forest in western Poland. Eighteen farmland bird species were recorded, of which 10 are included in the Polish Farmland Bird Index. Local alpha diversity of farmland birds was higher in older (5–10 yrs) and larger clear-cuts and declined with increasing distance to the forest-farmland edge. Local species communities displayed a high degree of turnover among clear-cuts and the gamma diversity of farmland birds was nearly twice as high in clear-cuts located close to the forest-farmland edge (i.e. below 1.3km from the edge; 17 species) compared to clear-cuts located in the forest interior (9 species), and in large clear-cuts (i.e. over 3.1ha, 17 species) compared to small clear-cuts (9 species). Our study shows that the additional habitat of clear-cuts in forest landscapes may potentially contribute to overall biodiversity of farmland birds in a region and should thus be included in monitoring and conservation of farmland birds.

Effect of forest clear-cutting on landslide occurrences: Analysis of rainfall thresholds at Mt. Ichifusa, Japan

Vegetation cover is an important factor for rainfall-induced landslides. We analyzed the effect of forest clear-cutting on the initiation of landslides using empirical rainfall intensity–duration (I–D) thresholds at Mt. Ichifusa, Japan, which is characterized by granitic rocks. Extensive clear-cutting was conducted for the forest industry during the late 1960s in the northern part of Mt. Ichifusa. This single episode of clear-cutting caused frequent shallow landslides triggered by rainfall. We interpreted orthorectified aerial photographs from 1969, 1976, 1980, 1985, 1990, 1995, 1999, and 2005 using GIS and mapped landslides based on these photographs. We then analyzed all rainfall events of the warm seasons (Apr.–Oct.) of 1952–2011 (60years) based on hourly rain gauge data. We used basic rainfall parameters such as mean rainfall intensity (I, mm/h) and duration (D, h) and estimated the return periods of these rainfall conditions. We investigated rainfall I–D thresholds for landslide occurrences in each period represented by the aerial photographs and assessed the relationships between landslide occurrences and topographic characteristics from 10-m DEMs. The results show that several landslides occurred after clear-cutting before 1976 but that they have occurred most frequently during the periods 1976–1980, 1980–1985, and 1990–1995. Numerous landslides occurred in these years at steeper and gentler slopes in the clear-cut area, but few landslides occurred in the non-clear-cut area. Rainfall analysis demonstrates that rainfall I–D thresholds after clear-cutting declined to half of those of the non-clear-cut area. The return periods of these rainfall I–D thresholds also declined to ~1year for short durations of <12h and to <3years for 72h in the clear-cut area. Our findings underscore the substantial hysteresis effects between clear-cutting and landslide occurrences at Mt. Ichifusa.

Butterflies take advantage of contemporary forestry: Clear-cuts as temporary grasslands

Contemporary forest landscapes in boreal and temperate environments, harvested by clear-cutting, contain various novel types of open spaces which are potentially suitable for species inhabiting natural or semi-natural open habitats. However, systematic analyses identifying the share of the regional species pool that can take advantage of this opportunity are missing. We assessed the importance of such forest openings for open-habitat butterflies in Estonia in Northern Europe by comparing butterfly species richness and composition in forest clear-cuts with their regional species pool. The species richness of butterflies in clear-cuts appeared to be remarkably high: we recorded altogether 81% of the total regional species pool across the study sites. Clear-cuts were inhabited by a very high share (79%) of regionally occurring grassland species, as well as nearly complete sets of open-habitat generalists and forest species. Redundancy analysis showed that clear-cuts in forests with different environmental characteristics harbour distinct butterfly assemblages, their contribution to the butterfly fauna in forest landscapes being thus complementary. This as well as several other lines of evidence indicate that most butterfly species can form resident populations in harvested forest landscapes. Our findings demonstrate that considering novel types of forest openings as ‘temporary meadows’ can substantially improve the conservation prospects for butterflies and other organisms that have traditionally been considered to inhabit grasslands and other open habitats in agricultural landscapes. Human-altered ecosystems may thus prove to be a viable alternative where restoring or maintaining natural and semi-natural habitats is impossible.

Habitat selection of Ortolan Buntings Emberiza hortulana on forest clear-cuts in northern Sweden

Ortolan Buntings Emberiza hortulana in Sweden used to occur mainly in farmland. Nowadays, a large proportion of the remaining population is found on forest clear-cuts in northern Sweden. Few studies have identified the types of clear-cuts that Ortolan Buntings prefer and whether these habitats are used for both breeding and foraging. We recorded presence and abundance of ortolan buntings on clear-cuts in Västerbotten County, northern Sweden. We sampled 123 clear-cuts (present N = 48, absent N = 75; total of 93–100 territories) and our results showed that clear-cut size, the number of remaining trees, bare soil percentage (≥10%) and narrow-leaved grass vegetation had a positive influence on ortolan bunting occupancy. The number of territories on clear-cuts was positively related to clear-cut size and number of remaining trees. Proximity to nearby farmland did not influence occupancy on clear-cuts. Behavioural observations indicated that the forest clear-cuts were used for both nesting and feeding. We discuss these results in relation to forest management policies and conservation of the ortolan bunting.

Estimating the fitness of a local discrete-structured population: From uncertainty to an exact number

The fitness of a local discrete-structured population is measured by the dominant eigenvalue λ1 of its matrix model, L, calibrated on empirical data. The data mined in case studies on local populations of Calamagrostis spp., perennial long-rhizome grasses colonizing rapidly open spaces (such as forest clear-cuts or meadows) due to their fast vegetative propagation, do provide for the accurate calculation of the transition part T in canonical sum of L=T+F, but leave the reproduction summand F uncertain. This ‘reproductive uncertainty’ (which is still constrained by the data and botanical knowledge) was amenable to calibration under the hypothesis that the adaptation is maximal for the given data and constraints, while the need to test the hypothesis experimentally motivated a drastic change in the technique of field experiments: from the description of above-ground parts of clones on a sample plot to the excavation of the whole colonies and analysing its system of rhizome reproductive links. In this paper, I report on how the “evolution” of experimental design and calibration technique has achieved an exact number in the estimation of fitness measure. As a by-product of that evolution, a new phenomenon has been discovered in the ontogeny of Calamagrostis epigeios, which has induced unexpected situations where the ever-working λ1(L) fails in the accuracy and needs an adjustment. The data-vs.-model dialectics behind the story are also commented on.

Despite Buffers, Experimental Forest Clearcuts Impact Amphibian Body Size and Biomass.

Forest buffers are a primary tool used to protect wetland-dependent wildlife. Though implemented widely, buffer efficacy is untested for most amphibian species. Consequently, it remains unclear whether buffers are sufficient for maintaining amphibian populations and if so, how wide buffers should be. We present evidence from a six-year, landscape-scale experiment testing the impacts of clearcutting, buffer width, and hydroperiod on body size and condition and biomass of breeding adults for two amphibian species at 11 vernal pools in the northeastern United States. We randomly assigned treatments (i.e., reference, 100m buffer, 30m buffer) across pools, clearcut to create buffers, and captured all spotted salamanders and wood frogs. Clearcuts strongly and negatively impacted size, condition, and biomass, but wider buffers mitigated effect magnitude and duration. Among recaptured individuals, for example, 30m-treatment salamanders were predicted to be about 9.5 mm shorter than, while 100m-treatment salamanders did not differ in length from, reference-treatment salamanders. Similarly, among recaptured frogs, mean length in the 30m treatment was predicted to decrease by about 1 mm/year, while in the 100m and reference treatments, length was time-invariant. Some, but not all, metrics recovered with time. For example, female new-captured and recaptured salamanders were predicted, respectively and on average, to weigh 4.5 and 7 g less in the 30m versus reference treatment right after the cut. While recaptured-female mass was predicted to recover by 9.5 years post-cut, new-captured-female mass did not recover. Hydroperiod was an important mediator: in the 100m treatment, cutting predominately affected pools that were stressed hydrologically. Overall, salamanders and female frogs were impacted more than male frogs. Our results highlight the importance of individualized metrics like body size, which can reveal sublethal effects and illuminate mechanisms by which habitat disturbance impacts wildlife populations. Individualized metrics thus provide critical insights that complement species occurrence and abundance-based population assessments.

Shift of rove beetle assemblages in reforestations: Does nativity matter?

Creating plantations after clear-cutting of native forests is a serious risk for biodiversity. Rove beetles were collected by litter sifting in non-native plantations (black locust, Scots pine, red oak), in native oak plantation and mature oak forest as control. We hypothesised that diversity and composition of the rove beetles in the mature forest would be different from those in the plantations. We expected that reforestation with native species would have less harmful effects on rove beetles than reforestation with non-native species. In accordance with our hypotheses the overall number of rove beetle individuals and species, as well as the diversity of hygrophilous and decaying material dependent rove beetles were significantly lower in the plantations than in the mature oak forest. However, the overall species richness and the diversity of hygrophilous and decaying material dependent rove beetles were significantly higher in the native plantation compared to the non-native ones. There was no significant correlation between the diversity of these rove beetles and the soil moisture and decaying woody materials as limiting resources; thus, our study did not support the resource quantity hypothesis. The cover of herbs and shrubs, the soil temperature and soil pH were the most important factors controlling the diversity of rove beetles. Our results suggest that reforestation with native tree species provides more suitable habitat for rove beetles than non-native ones. However, it seems that rove beetle assemblages did not recover even after 40 years of reforestation with native tree species due to their specific ecological demands.

Arthropods and novel bird habitats: do clear-cuts in spruce plantations provide similar food resources for insectivorous birds compared with farmland habitats?

Arthropods, and insects in particular, constitute important food resources for several higher trophic levels like birds. Their abundance and diversity is likely to differ between habitat types depending on the local conditions and resources. This may have important consequences for arthropod consumers that occupy structurally different habitat types. Most bird-focused studies address, however, habitats at the structural, vegetation-based level and disregard the presence of sufficient quantities and qualities of arthropod prey items. Here, we compare the quantity and quality of ground-dwelling and above-ground arthropods as food resources for early-successional birds between two structurally different human-modified habitat types sharing similar bird assemblages: low-intensity farmland areas and plantation forest clear-cut areas in the south of Belgium. Forest clear-cut patches constitute a novel habitat for so-called ‘farmland’ birds. Our results show that arthropod abundance is substantially higher in farmland than in forest clear-cuts, although arthropods are slightly larger in clear-cuts. Higher arthropod abundance is associated with higher ground-level temperature in farmland. Although both habitat types host the same spectrum of arthropod species, forest and farmland management practices induce different conditions for food quantity and, to some extent, food quality for insectivorous birds. We discuss the mechanisms behind the observed pattern of arthropod abundance and the fitness-related consequences of contrasting food availability in farmland and forest clear-cut habitats for early-successional bird species.

Re-defining Environmental Harms: Green Criminology and the State of Canada’s Hemp Industry

Green criminology has been developing for more than 20 years as a field of criminological inquiry that grapples with defining and exploring environmental harms. This perspective includes approaches that look beyond legally defined environmental crimes, highlighting permissible activities that cause environmental deterioration, such as clear-cutting of forests, and prohibited activities that benefit the environment, such as pedicabs. Extending the criminological gaze helps green criminology identify unacknowledged environmental harms. The article draws from postmodernist/poststructuralist concepts to work past merely defining actions as either harmful or harmless, highlighting the complexity of socio-ecological effects and the importance of extending the conceptual boundaries of harm. Canada’s experiences with industrial hemp provide a fitting example. The heavily regulated Canadian hemp industry offers an important case for investigating the impacts of social constraints that limit the industry’s capacity to benefit the environment. Qualitative interviews reveal negative public perceptions, over-restrictive regulatory requirements, and insufficient technological capabilities as important obstacles to a fuller realization of hemp’s environmental benefits. Informed by constitutive criminology, chaos criminology, and Halsey’s important critique, the article adds to postmodernist/poststructuralist developments in green criminology.

Potential biodiversity impacts of forest biofuel harvest: lichen assemblages on stumps and slash of Scots pine

Harvesting stumps and logging residues for energy production may have negative impacts on forest species, especially those associated with dead wood. We assessed the potential impact of biofuel harvest on epiphytic lichens by studying the lichen assemblages on stumps and downed fine woody debris (FWD) of Scots pine (Pinus sylvestris L.) in clear-cut, mature managed, and old-growth forest stands in eastern Finland. We also examined the impact of tree retention level and prescribed burning on these assemblages. A total of 102 lichen species (including 13 red-listed species) were observed, with 95 species on stumps and 69 species on downed FWD. Composition of the species assemblages differed between stumps and downed FWD and between stumps of different age. Tree retention (in comparison with clear-cut sites) and prescribed burning resulted in a slightly higher species richness on cut stumps 12 years after harvest but did not affect the assemblages on downed FWD or older stumps. We conclude that stumps and downed FWD of Scots pine can host high numbers of lichen species, including red-listed ones. Most of the species occurred also on other substrates and are, therefore, not likely to be affected by biofuel harvest. However, for dead wood dependent lichen species, intensive biofuel harvest is potentially harmful, though the severity of this impact likely depends on the landscape-level availability of other woody substrates.

Clear-cuts in production forests: From matrix to neo-habitat for butterflies

Butterfly conservation in Europe is mainly focused on well-defined grassland habitat patches. Such an approach ignores the impact of the surrounding landscape, which may contain complementary resources and facilitate dispersal. Here, we investigated butterfly species richness and abundance in a habitat normally regarded as unsuitable matrix: production forestry clear-cuts. Butterflies were recorded in 48 clear-cuts in southern Sweden differing with regards to the time since clear-cutting and land-use history (meadow or forest based on historical maps from the 1870s). All clear-cuts had been managed as production forests for at least 80–120 years. A total of 39 species were found in clear-cuts of both land-use histories, but clear-cuts with a history as meadow had on average 34% higher species richness and 19% higher abundance than did clear-cuts with a history as forest. No effect of the time since clear-cutting was found, irrespective of land-use history, which was likely due to the narrow timespan sampled (<8 years). The absence of temporal effect suggests that clear-cuts may provide butterflies with valuable resources for 10–15 years. Assuming a 100 year forest rotational cycle, this means that 10–15% of the total forested area are made up by clear-cuts valuable to butterflies, which corresponds to an area about four times as large as that of species-rich semi-natural grasslands. The study illustrates the importance of considering land-use legacies in ecological research and question the landscape-ecological view that clear-cuts make up an unsuitable matrix for butterflies. Moreover, forest conservation management with special attention to land-use history may increase the quality of the landscape, thus facilitating butterfly metapopulation persistence. Given their large area and assets of nectar and host plant resources, clear-cuts must be considered as a butterfly habitat in its own right. Being a man-made environment with short history, we might call it a neo-habitat.

Does hybridization with a widespread congener threaten the long-term persistence of the Eastern Alpine rare local endemic Knautia carinthiaca?

Interspecific hybridization, especially when regularly followed by backcrossing (i.e., introgressive hybridization), conveys a substantial risk for many endangered organisms. This is particularly true for narrow endemics occurring within distributional ranges of widespread congeners. An excellent example is provided by the plant genus Knautia (Caprifoliaceae): Locally endemic K.carinthiaca is reported from two isolated populations in southern Austria situated within an area predominantly occupied by widespread K.arvensis. While K.carinthiaca usually inhabits low-competition communities on rocky outcrops, K.arvensis occurs mainly in dry to mesic managed grasslands, yet both species can coexist in marginal environments and were suspected to hybridize. Flow cytometry revealed that diploid K.carinthiaca only occurs at its locus classicus, whereas the second locality is inhabited by the morphologically similar but tetraploid K.norica. In the, therefore, single population of K.carinthiaca, flow cytometry and AFLP fingerprinting showed signs of introgressive hybridization with diploid K.arvensis. Hybridization patterns were also reflected in intermediate habitat preferences and morphology of the hybrids. Environmental barriers to gene flow seem to prevent genetic erosion of K.carinthiaca individuals from the core ecological niches, restricting most introgressed individuals to peripheral habitats. Efficient conservation of K.carinthiaca will require strict protection of its habitat and ban on forest clear cuts in a buffer zone to prevent invasion of K.arvensis. We demonstrate the large potential of multidisciplinary approaches combining molecular, cytometric, and ecological tools for a reliable inventory and threat assessment of rare species.

Evaluating forest management intensity on an umbrella species: Capercaillie persistence in central Europe

Deforestation and fragmentation of forests worldwide are negatively impacting biodiversity. The capercaillie (Tetrao urogallus) is an endangered umbrella species of montane forests in central Europe. Despite its status, it has largely been overlooked in forest management planning in the Carpathian Mountains, a biodiversity hotspot within the European Union. Previous investigations of timber management effects on capercaillie have shown contradictory results within Europe; habitat loss and fragmentation due to intensive forest management have been implicated in population declines, while other studies have suggested neutral or positive effects. In Romania, recent changes in forest management have shifted from extensive, selective logging to intensive clearcutting; this change provides the opportunity to assess the effects of harvesting on capercaillie numbers across a full range of forest management intensities, thereby addressing discrepancies in the literature. Across the Southern and Eastern Carpathian mountains from 2009–2011, we used spring counts of capercaillie males at leks to evaluate the impact of forest management, other human activities, and habitat at two spatial scales – stand (∼2ha) and landscape (∼300ha). At the landscape level, the proportion of forest clearcuts and intensity of tourism had significant negative effects on the number of capercaillie males in the lek. In contrast, low intensity selective logging had a positive effect at the local stand (lek) level. Large scale (landscape level) forest clear-cutting had a negative effect on the capercaillie population – areas comprised of clearcuts of 30% reduced male lek counts by 76%. The protection of intact mature and old-growth forests, and forest management practices that emulate natural disturbance processes are recommended to support habitat of this critical umbrella species and associated biodiversity.

Linking GPS Telemetry Surveys and Scat Analyses Helps Explain Variability in Black Bear Foraging Strategies

Studying diet is fundamental to animal ecology and scat analysis, a widespread approach, is considered a reliable dietary proxy. Nonetheless, this method has weaknesses such as non-random sampling of habitats and individuals, inaccurate evaluation of excretion date, and lack of assessment of inter-individual dietary variability. We coupled GPS telemetry and scat analyses of black bears Ursus americanus Pallas to relate diet to individual characteristics and habitat use patterns while foraging. We captured 20 black bears (6 males and 14 females) and fitted them with GPS/Argos collars. We then surveyed GPS locations shortly after individual bear visits and collected 139 feces in 71 different locations. Fecal content (relative dry matter biomass of ingested items) was subsequently linked to individual characteristics (sex, age, reproductive status) and to habitats visited during foraging bouts using Brownian bridges based on GPS locations prior to feces excretion. At the population level, diet composition was similar to what was previously described in studies on black bears. However, our individual-based method allowed us to highlight different intra-population patterns, showing that sex and female reproductive status had significant influence on individual diet. For example, in the same habitats, females with cubs did not use the same food sources as lone bears. Linking fecal content (i.e., food sources) to habitat previously visited by different individuals, we demonstrated a potential differential use of similar habitats dependent on individual characteristics. Females with cubs-of-the-year tended to use old forest clearcuts (6–20 years old) to feed on bunchberry, whereas females with yearling foraged for blueberry and lone bears for ants. Coupling GPS telemetry and scat analyses allows for efficient detection of inter-individual or inter-group variations in foraging strategies and of linkages between previous habitat use and food consumption, even for cryptic species. This approach could have interesting ecological implications, such as supporting the identification of habitats types abundant in important food sources for endangered species targeted by conservation measures or for management actions for depredating animals.