Evaluating forest management intensity on an umbrella species:
Capercaillie persistence in central Europe
, Marek Svitok
, Martin Tejkal
, Pedro J. Leitão
, Robert C. Morrissey
, Meelis Seedre
, Joseph B. Fontaine
Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Kamy
´cká 129, Praha 6 – Suchdol 16521, Czech Republic
PRALES, Odtrnovie 563, 013 22 Rosina, Slovakia
Department of Biology and General Ecology, Faculty of Ecology and Environmental Sciences, Technical University in Zvolen, Masaryka 24, 96001 Zvolen, Slovakia
Eawag Swiss Federal Institute of Aquatic Science and Technology, Department of Aquatic Ecology, Centre of Ecology, Evolution and Biogeochemistry, Seestrasse 79,
CH-6047 Kastanienbaum, Switzerland
Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamy
´cká 129, Praha 6 – Suchdol 165 21, Czech Republic
Geography Department, Humboldt-Universität zu Berlin, Unter dem Linden 6, 10099 Berlin, Germany
School of Veterinary and Life Sciences, Murdoch University, Perth 6150, Australia
Received 4 January 2015
Received in revised form 1 July 2015
Accepted 3 July 2015
Available online 11 July 2015
Deforestation and fragmentation of forests worldwide are negatively impacting biodiversity. The caper-
caillie (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 sug-
gested 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 moun-
tains 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 (2 ha) and landscape
(300 ha). At the landscape level, the proportion of forest clearcuts and intensity of tourism had signif-
icant 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 prac-
tices that emulate natural disturbance processes are recommended to support habitat of this critical
umbrella species and associated biodiversity.
Ó2015 Elsevier B.V. All rights reserved.
Over the past century, global declines in mature forested area
(Hansen et al., 2013) and biodiversity related to habitat loss, frag-
mentation, and overexploitation are causing increased concern
among natural resource managers and conservationists (Wilcove
et al., 1998). Large-scale clear-cutting of forested landscapes has
driven the vast majority of forest species losses (Lamberson and
McKelvey, 1992; Wallenius et al., 2010) and much attention has
been devoted to alternative harvest strategies and associated man-
agement to retain forest species within landscapes (e.g. Franklin
and Johnson, 2012). In areas such as central Europe that histori-
cally have been heavily forested but now have limited and increas-
ingly fewer areas of old-growth forest cover (Mackey et al., 2014),
identifying management impacts and alternatives is a priority.
Here, we use the capercaillie, Tetrao urogallus, to evaluate the
effects of logging old forests on mating habitat selection. The
capercaille is considered an umbrella species within the region
and an indicator of structurally rich forest conditions (Suter
et al., 2002). Capercaillie populations in central Europe have
declined rapidly in recent decades (Storch, 2007a). Identifying
0378-1127/Ó2015 Elsevier B.V. All rights reserved.
E-mail address: mikolasm@ﬂd.czu.cz (M. Mikoláš).
Forest Ecology and Management 354 (2015) 26–34
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forestry practices that may aid in maintaining viable population
levels of this species within forested landscapes are vital to ensure
their persistence in the landscape alongside many other species
commonly represented in these habitat types.
Capercaillie inhabits forests of Eurasia, and they are associated
with extensive natural, old-growth or young open canopy forests,
characterized by high levels of structural heterogeneity, particu-
larly, multistoried tree layers and abundant cover of ericaceous
understory shrubs (Bollmann et al., 2005; Klaus et al., 1989;
Storch, 2002; Suter et al., 2002). Because capercaillie is strongly
associated with open canopy forest and has a relatively large home
range, it is considered an indicator species for high biodiversity and
protection of its habitat will beneﬁt other old-growth forest spe-
cies as well (Pakkala et al., 2003; Suter et al., 2002).
Lek sites, where males display in spring, are particularly vulner-
able to disturbance by humans and may be readily abandoned, as is
common with many species of grouse with this mating system (e.g.
Hess and Beck, 2012; Klaus et al., 1989). Anthropogenic activities,
especially the intensiﬁcation of forest management, have resulted
in the signiﬁcant loss and fragmentation of suitable capercaillie
habitat in many parts of western and central Europe (Storch,
2007a). In many European countries, capercaillie populations are
now artiﬁcially maintained using release projects, specialized habi-
tat management measures, or predation control (Klaus, 1997;
Marshall and Edwards-Jones, 1998; Siano and Klaus, 2013;
Storch, 2000). Capercaillie is a red-listed species in Annex I of the
EU Birds Directive in most European countries, and it is a speciﬁc
designated feature of many of the Natura 2000 sites (Storch,
One of the remaining strongholds of capercaillie populations in
central Europe is the Carpathian Mountains that stretch from the
Czech Republic east to Ukraine and extend to southern Romania.
The Carpathian Mountains possess one of the largest areas of
old-growth and natural forests in Europe with thriving populations
of brown bears (Ursus arctos), lynx (Lynx lynx), grey wolves (Canis
lupus), european bison (Bison bonasus)(Veen et al., 2010), and, his-
torically, a stable and self-sustainig capercaillie population.
Historic land uses, such as grazing and selective logging, main-
tained habitat conditions suitable for capercaillie (Hancock et al.,
2011; Klaus et al., 1989). However, management practices have
changed in the last few decades, with more large scale clearcuts
and associated landscape fragmentation taking place, mainly due
to new post-communist forest restitution laws (privatization of
forest lands) and increasing accessibility by new forest roads
(Knorn et al., 2012a,b).
Habitat loss and fragmentation related to logging activities have
been shown to negatively impact the reproductive success of
capercaillie in boreal forests (Lakka and Kouki, 2009). Similarly,
in western and central Europe, a decline of capercaillie populations
also has been linked to habitat loss through fragmentation and log-
ging (Storch, 2007a). In contrast, recent evidence from boreal for-
ests indicates that the capercaillie is relatively tolerant to
changes in forest management regimes and populations will per-
sist in the long term, even in landscapes with large-scale clearcut-
ting (Miettinen, 2009; Wegge and Rolstad, 2011). However,
capercaillie distribution in boreal forests is continuous and not as
fragmented as in other areas of Europe (Storch, 2007a), and boreal
forest regeneration patterns and dynamics is different compared to
temperate regions of Europe.
Given clear declines of capercaillie associated with intensiﬁca-
tion of forest management over the last two decades, the main
objective of this study was to identify the most important predic-
tors inﬂuencing capercaillie male numbers in the leks in the
Southern and Eastern Carpathians. We focused on stand and land-
scape features surrounding lek centres where mating occurs
because they are critically important for sustaining local
populations (Miettinen et al., 2005; Picozzi et al., 1992; Saniga,
2003). Speciﬁcally, we were interested in how human land use,
intensity of forest management, habitat fragmentation, and loss
of suitable habitat affect capercaillie abundance at the display
grounds. Outcomes from this study highlight threats to capercaillie
and identify forest management practices compatible with conser-
2.1. Study area
Across the Southern and Eastern Carpathians within Romanaia,
we sampled forests of 11 separate mountains. The potential size of
suitable habitats (mountain forests with elevation >1000 m above
sea level) was estimated on 190,113 ha; total area of all studied lek
centres (1 km radius around the lek centres) was 6594 ha. The cli-
mate of Romania ranges from temperate to continental, and cold
winters and high precipitation are typical for mountainous areas.
The mean winter temperature is 5.2 °C with mean winter precip-
itation of 355 mm, while mean summer temperature is 13.9 °C and
summer precipitation of 1095 mm in the study area (Toader and
2.2. Capercaillie population in the study area
Based on hunting surveys across Romania, the total population
of Capercaillie was estimated to be 10,000 birds as of 2007
(Storch, 2007b). During our the study period, hunting of capercail-
lie was legal in Romania; however, since 2012, hunting of caper-
caillie has been prohibited, although ongoing illegal hunting may
still have serious effects on capercaillie populations in some
regions. The lek centres studied were located at altitudes ranging
from 1320 to 1722 m above sea level. The prevalent vegetation
type was Norway spruce (Picea abies (L.) Karst.) forest (86%), mixed
European larch (Larix decidua Mill.)-Norway spruce forest (9.5%),
and mixed Norway spruce-Silver ﬁr (Abies alba Mill.)-European
beech forest (Fagus sylvatica L.) (4.5%).
2.3. History of forest management in the study area
The capercaillie habitats in the Carpathians are mostly high ele-
vation natural forests with old-growth characteristics, such as
large amounts of dead wood, elevated root plates, and
multi-cohort open canopy stands (see the Appendix). Only 9% of
the lek centres occurred in areas of naturally regenerated open
canopy stands (60 years old) resulting from abandonment of
grazing of montane pastures. In the past, all stands were difﬁcult
to access and forest management was predominantly selective
single-tree or group logging made by the shepherds who used
the surrounding mountain pastures during the summer (Huband
et al., 2010). Forest management practices changed considerably
in the studied area after the collapse of communism in 1989.
New forest roads were built into formerly inaccessible areas and
large areas of state forest were restituted to prior owners resulting
in increased forest harvesting at large spatial scales (Grifﬁths et al.,
2014; Knorn et al., 2012a,b). In addition, some forested areas were
ofﬁcially categorized as pastures, thus enabling owners to make
large clearcuts without any control, and illegal logging has
occurred during the post-communist era. Extensive clearcutting
forestry has also occurred in protected areas, such as national
parks. Based on remote sensing data (Landsat imagery; Table 1,
Grifﬁths et al., 2014), in our study plots the mean percentage of
clearcuts after 1990s in protected areas is higher (24.6%), com-
pared to unprotected areas (16.4%). Based on the forest ownership
M. Mikoláš et al. / Forest Ecology and Management 354 (2015) 26–34 27
data (Abrudan, 2012) in our study plots, 43% were private and 57%
owned by state. For the whole of Romania (as of early 2013), over
4.4 million hectares of state, public, and private forest lands were
administered by state and experimental forest districts, with a fur-
ther 1.7 million hectares of forest land administered by private for-
est districts (Marinchescu et al., 2014). It is evident that changes in
ownership have resulted in changes in forest management and
structure across multiple scales (Grifﬁths et al., 2014; Knorn
et al., 2012a,b)
2.4. Data sampling
2.4.1. Study design
Clearcutting has been widely documented to lead to local extir-
pation of capercaillie (Storch, 2007b). Our objective was not to doc-
ument population declines, but rather to identify forest practices
that would permit persistence of capercaillie. Therefore, we sam-
pled forest conditions representing a range of no harvest to partial
harvest within the known range of capercaillie. Using capercaillie
distribution and density maps provided by the Forest Research
and Management Institute of Romania (ICAS), localities with the
highest capercaillie densities across 11 mountain ranges were
intensively surveyd in a 1 km radius area (314 ha), which was con-
sidered to be the average territorial area used by capercaillie males
during the lekking period (Storch, 1995). We identiﬁed 21 lek cen-
tres in Fa
(n= 4), Rodnei (n= 4), Harghita (n= 3), Maramuresß
(n= 3) Piatra Craiului (n= 1), Bucegi (n= 1), Diham (n= 1), Prisciu
(n= 1), H^
asßmasß(n= 1), Ca
˘limani (n= 1), and Piatra Mare (n=1)
2.4.2. Data collection
Capercaillie males gather in lek centres to display and compete
for females; within display grounds, males establish display terri-
tories spaced 50 m apart. Counting of males at lek centres is a
widely used technique across many species of grouse to monitor
population trends (Miettinen et al., 2005; Picozzi et al., 1992;
Saniga, 2003). During the daytime period, they remain within a
radius of approximately 1 km of the lek centre (Storch, 1995).
Plot locations, deﬁned by lek centres, were determined by the posi-
tion of the alpha capercaillie male; GPS coordinates recorded after
birds ﬁnished displaying during each visit. These lek centres are
usually located in the same sites annually and may be used for sev-
eral decades (Klaus et al., 1989). Lek surveys were conducted from
March to May during 2009–2011 with two visits per season; the
maximum counts were used in the analyses. Surveys were per-
formed from 03:00 to 09:00, and all observed or heard capercaillie
males were recorded. During the day we returned to look for signs
and display stances, which helped to clarify the capercaillie male
numbers in the leks.
2.4.3. Environmental data and scale consideration
To understand drivers of capercaillie abundance we collected
data on three principal types of data: habitat, forest management,
and human activity, excluding forest management activities
(Table A1). Data were restricted to stand scale and landscape scale;
stand scale measurements were deﬁned as an 80 m radius circular
plot (2.1 ha), and landscape scale as a 1 km radius area (314 ha) to
evaluate broader scales impacts, such as forest management and
intensity of tourism. Landscape scale considerations were also
deﬁned by distance based variables for habitat or human activity
variables (e.g. distance to the closest building, water spring, etc.).
2.4.4. Habitat measurements
Habitat characteristics were measured in the lek centres during
the summer months. We used an extensive list of site characteris-
tics to evaluate possible lek centre preferences in the
under-researched part of the species distribution in Southern and
Eastern Carpathians. The variables recorded included topography,
surface type, main canopy characteristics, understorey, ground
vegetation, dead wood, soil, habitat use by large herbivores, human
land use, type of forest management, and the landscape; for a com-
plete listing, see Table A1.
Forest extent and losses in each study plot (N= 21, plot size = 314 ha) with mean values (italicized) representing subregions of the Southern and Eastern Carpathians in Romania
2009–2011. For every study plot the maximum number of capercaillie males lekking in the display ground (centre of the study plot) and maximum number of females recorded
during the spring season are reported. The top portion of the table shows the values in study sites with no protection regulations while the bottom portion shows the protected
1985–1990 1990–2010 1990–2010 1990–2010 Conservation status Male numbers Female numbers
Clearcut (ha) Forest (ha) Clearcut (ha) Forest (ha) Clearcut (%) Average forest loss
0 314.1 12.96 301.14 4.1 16.40% No protected 7 5
0 239.85 6.3 234.54 1.7 4 2
0 240.57 33.21 207.36 10.6 2 2
3.06 304.65 178.47 129.24 55.8 2 0
0 135.09 9.27 125.82 331
0 283.32 45.81 238.23 14.4 1 2
1.89 267.93 6.48 263.34 1.5 3 3
1.26 291.42 108.18 184.5 34 1 1
4.95 253.62 75.51 183.06 22.5 1 1
1.24 258.95 52.91 207.47 16.4
21.78 165.69 19.62 167.85 0.7 21.14% Protected 3 1
0 303.03 135.72 167.31 43.2 4 2
9 237.42 3.6 242.82 1.7 1 1
1.44 281.34 123.57 159.21 38.9 3 1
0 266.85 225.81 41.85 71.6 1 1
0 212.22 119.97 92.61 38.1 1 2
8.19 224.19 77.04 155.34 21.9 2 1
0 277.65 5.67 272.88 1.5 2 1
61.47 200.34 3.06 258.75 18.6 2 3
7.02 130.23 51.39 85.86 14.1 2 1
17.01 297.36 132.48 181.89 36.8 6 8
1.08 258.03 27.99 231.12 8.6 9 4
10.58 237.86 77.16 171.46 21.14
28 M. Mikoláš et al. / Forest Ecology and Management 354 (2015) 26–34
2.4.5. Forest management
Forest management activities were evaluated at the stand and
landscape levels. At the stand scale, selective logging intensity
was measured based on percent canopy removal and presence of
forest roads within 80 m plot radius (2.1 ha). At the landscape
scale, clearcut estimates were based on the proportion of the
1 km radius (314 ha) plot area that was clearcut within the previ-
ous ﬁve years (since 2005) and larger than one ha. A detailed list of
variables and an explanation of variable scales are provided in
Table A1 and Table 2, respectively.
2.4.6. Impact of (non-logging) human activity
To evaluate human land use intensity, activities were deﬁned
based on maps and direct enquiries of local and regional experts
(administrators of national and natural parks, forestry administra-
tors, and local shepherds), similar to Rösner et al. (2013). Every
activity was classiﬁed on a scale from 0 to 5 to deﬁne intensity,
with ‘0’ being the least intensive and ‘5’ being the most intensive
(Table 2). The tourist activity was evaluated for the peak tourist
period that included weekends during the winter/spring period;
it was based on the number of tourists who visited the 314 ha plot.
Fig. 1. Locations of the studied lek centres.
Detailed description of the scales of measured variables.
01 2 3 4 5
Intensity of tourism (314 ha
No tourism <10 person/day 10–50 people/day 50–100 people/day 100–150 people/day >150
Selective logging intensity
(2.1 ha plot)
Presence of a forest road,
no cuttings in the lek
Cuttings in the lek
Cuttings 1–15% Cuttings 15–30% Cuttings >30%
Intensity of grazing (314 ha
No grazing Grazing of <15 standard
livestock units irregularly
Grazing of 15–150
Grazing of 15–150
livestock units regularly
Intensity of hunting (314 ha
No hunting Legal hunting of 1
capercaillie per 15 years
Legal hunting of 1
Legal hunting of 1
Legal hunting of more
than 1 capercaillie per
Spatial distribution of
vegetation clustering (ID)
(2.1 ha plot)
Obscure clusters Small clear clusters Large clear clusters Small orientated clusters Large
M. Mikoláš et al. / Forest Ecology and Management 354 (2015) 26–34 29
The number of tourists was based on information from
administrators of national and natural parks and tourist centre
administrators (e.g. ski-lift companies, mountain cottages owners).
Distance-based variables, such as distance to the closest buildings,
and distance to closest road, were also used to evaluate human
activity and presence.
2.5. Statistical analyses
Because a large numbers of explanatory variables were mea-
sured for a relatively small sample size (n= 21), the number of
explanatory variables was reduced prior to analyses to avoid prob-
lems with collinearity (Dormann et al., 2013). Principal component
analysis (PCA) on correlation matrices of landscape characteristics
(12 variables), the cover of individual species in the tree layer (7
variables), the shrub layer (11 variables), and the herb layer (27
variables) was used to reduce the dimensionality. The broken stick
model was used to identify the number of non-trivial principal
components (Jackson, 1993). This selection process resulted in
one principal component (PC) for the landscape characteristics,
two PCs for the tree layer, two PCs for the shrub layer, and four
PCs for the herb layer (see Table A2).
The relationships between capercaillie numbers and environ-
mental characteristics were analysed using generalized linear
models (GLM; McCullagh and Nelder, 1989). In addition to the
latent variables described above, the remaining variables (see
Tables A1 and A2) were then combined to form a list of candidate
predictors. An exhaustive best-subset regression procedure was
employed in search of the most parsimonious model (McLeod
and Xu, 2009). Poisson distribution and logarithmic link-function
were used within GLMs to relate numbers of males in the lek cen-
tres with the predictors. The Bayesian information criterion (BIC)
was used for model selection. Due to the limiting number of
degrees of freedom, only those models with a maximum of 5
explanatory variables were considered in the analyses.
Parameters of the ﬁnal model were tested using likelihood ratio
tests (Crawley, 2007), and the model ﬁt was assessed using
McFadden’s (pseudo) determination coefﬁcient (McFadden,
1973). Standardized regression coefﬁcients were calculated to
facilitate direct comparisons across signiﬁcant predictors, regard-
less of differences in the scale of the predictors. The relative impor-
tance of explanatory variables on capercaillie abundance was
assessed by variation partitioning (Borcard et al., 1992). The
deviance explained by each variable was expressed as a percentage
of the total variation, represented by the deviance of a null model.
Partial regression plots and effect plots were constructed to depict
partial relationships in the ﬁnal model (Fox, 2001). Partial regres-
sion plots allowed us to visualize the effect of each predictor after
adjusting for all the other predictors in the ﬁnal model. Effect plots
display ﬁt for each partial relationship while the other predictors
are ﬁxed at mean values. All analyses were performed in R (R
Development Core Team 2010) using the bestglm (McLeod and
Xu, 2011) and vegan (Oksanen et al., 2011) packages.
Active capercaillie leks were not found within recent clearcuts
and they were not detected where clearcutting exceeded 62% of
the surrounding landscape (314 ha) (Fig. A1). Almost all lek centres
were situated in forests with old-growth characteristics and lim-
ited anthropogenic inﬂuence (see Table A1). Only two lek centres
were situated in younger forests, but these were in fact abandoned
pastures and not clearcut areas. The average forest cover in the
314 ha plot was 187 ha (60%), with a range between 79 ha (25%)
and 301 ha (96%); the remaining areas were covered by mountain
pastures or clearcuts. The average number of capercaillie males
counted in the lek centres was 2.9 (SD = 2.15), and the average
number of females was 2 (SD = 1.8) (see Table 1.)
The best model to explain the number of male capercaillie at lek
centres contained three variables: the proportion of clearcuts at
the landscape scale and intensity of tourism negatively inﬂuenced
male capercaillie numbers, but selective logging intensity at the
stand scale had a positive effect (Table 3). The overall model signif-
icantly explained 62.8% of the deviance (
= 17.27, p< 0.001), and
partial regression plots indicated the model provided a reasonable ﬁt
to the data (Fig. 2a–c). Based on standardized regression coefﬁcients,
the effect size of landscape scale clearcuts was largest. Variation par-
titioning indicated that >37% of the deviance in male numbers could
be explained by the proportion of clearcuts; holding the effect of
other variables constant, clearcuts of 30% reduced male lek counts
by more than four times (Fig. 2d). The deviance attributable to tour-
ism and selective logging intensity amounted to 31% and 20%,
respectively. Differences between no (0) and intensive (5) tourism
and selective logging indicated a 4.4-fold decrease and a 3.7-fold
increase in male lek counts, respectively, when other factors were
held constant (Fig. 2e–f).
Of all the studied variables, three anthropogenic factors had the
highest inﬂuence on capercaillie numbers: the proportion of clear-
cuts, intensity of tourism, and selective logging. Romania has expe-
rienced massive socio-economic and institutional change over the
past 25 years (Knorn et al., 2012a,b) that has impacted ownership
and human land use, such as forestry and tourism. Negative effects
of emerging land use (increased forest exploitation and tourism)
were evident, while historic forest practices were positively related
to capercaillie numbers. The average capercaillie male numbers per
lek were similar to numbers detected in other regions, where long
term declining population trends were detected (e.g. Zawadzki and
Zawadzka, 2012; Saniga, 2012).
4.1. Capercaillie and forest harvesting
The effects of forest harvesting on capercaillies depend on the
intensity and extent of harvesting practices (Klaus, 1991). The
selective logging intensity in the lek centres had a positive effect
on capercaillie male numbers. In dense managed stands, selective
logging reduces canopy cover in a manner similar to small-scale
natural disturbance processes, which makes the forest canopy
more open and increases structural heterogeneity of the stand
(Broome et al., 2014; MacMillan and Marshall, 2004).
Multistoried tree layers with gaps and abundant cover of erica-
ceous understory shrubs may improve summer forage and cover
from predators for capercaillies. Although our results did not show
a signiﬁcant relationship between number of capercaillie males
and bilberry cover, the capercaillie habitats typically contained
extensive patches of bilberry; based on other studies, we do know
Parameters of the ﬁnal GLM model showing relationships between the number of
capercaillie males in the lek centres and the proportion of clearcuts, intensity of
tourism, and intensity of forest management. Standardized regression coefﬁcients (b),
regression coefﬁcients (b), standard errors (se), test statistics (
) and probabilities (p)
Intercept 2.036 0.187 44.54 <0.001
Proportion of clearcuts 0.41 0.048 0.009 14.32 <0.001
Intensity of tourism 0.22 0.296 0.071 9.86 0.002
Selective logging intensity 0.24 0.262 0.083 5.35 0.021
30 M. Mikoláš et al. / Forest Ecology and Management 354 (2015) 26–34
that bilberry is an important habitat component (eg. Wegge and
Rolstad, 2011; Hancock et al., 2011; Storch, 2002, 1993).
At the landscape scale, the proportion of clearcuts surrounding
the lek centres had an exponential negative effect on capercaillie
numbers (Fig. 2d), as suitable habitats are lost and fragmented
by clearcuts. The relationship between habitat fragmentation and
extinction has been demonstrated to be highly non-linear
(Fahrig, 2003), thus, the presence of clearcuts also has broader
implications to population and metapopulation dynamics through-
out the region.
Our results are in contrast with the ﬁndings of studies con-
ducted in the boreal zone (Miettinen, 2009; Wegge and Rolstad,
2011); they observed that capercaillie were tolerant to clearcutting
across the landscape because capercaillie were also able to use
open canopy middle-aged plantations (>30 years old) with bilberry
ground cover. The ﬁndings of these studies cannot necessarily be
applied to central Europe or the Southern and Eastern
Carpathians, which are all outside the boreal zone. Capercaillie dis-
tribution in central Europe is very fragmented compared to the
boreal zone; capercaillie persist here in patchy populations embed-
ded in a mountainous landscape (Storch, 2007a). In fragmented
conditions of central Europe it is very difﬁcult to maintain viable
capercaillie populations, which require ca. 250 km
and an esti-
mated 470 interacting capercaillie individuals (Grimm and
Storch, 2000). Inter-patch dispersal is very important for the per-
sistence of capercaillie, thus, high habitat connectivity is important
for metapopulation dynamics. In the Carpathians, suitable caper-
caillie habitats are a mere small ’habitat band’ of coniferous dom-
inated forest situated between mountaintops and the deciduous
forests of lower altitudes. In case of intensive clearcutting, alterna-
tive forest nearby which represents suitable capercaillie habitat is
thereby naturally limited. When stepping stones are lost and habi-
tat connectivity is disrupted by clearcuts on large spatial scales, as
in this study, migration of individuals between populations could
be severely limited and population persistence may be threatened
because small isolated populations are unlikely to survive
(Segelbacher et al., 2003). These factors has lead to extinction debt
in other small and isolated metapopulations (Pullin, 2002). In addi-
tion, the typical management practices in central Europe do not
enable creation of open canopy forest structure suitable as caper-
caillie habitat (Bollmann et al., 2005). Plantation establishment
after clearcutting is mandatory in central Europe; the result is very
dense forest canopies with very little ground vegetation, particu-
larly critical bilberry cover (Vaccinium myrtillus L.), which provides
food for adults, invertebrates for chicks, and hiding and thermal
cover (Hancock et al., 2011; Storch, 1993).
The negative landscape level effect of large clearcuts on caper-
caillie numbers was signiﬁcant and outweighed the positive effects
of selective logging intensity. These clearcuts cover large areas and
might almost completely remove the narrow spruce forest vegeta-
tion belt in some areas. Unlike smaller clearcut patch harvesting
that creates ﬁne grain forest fragmentation that may be suitable
for capercaillie in the boreal forests (Sirkiä et al., 2011), large clear-
cuts cause long-term loss of habitat with no alternative options of
suitable habitats in the surrounding forests where the birds could
migrate. Increased harvesting using clearcuts practices are largely
related to restitution laws implemented after the collapse of com-
munism in 1989; forest harvesting increased sharply in two waves
around 1995 and 2005 (Knorn et al., 2012a). Clearcuts recorded in
our study (younger than 5 years) in the capercaillie habitats coin-
cide with the second wave of harvesting after 2005. The area of
suitable habitats is declining and becoming more fragmented as
a result of large-scale clearcuts in the Carpathians, with little dif-
ferentiation in forest management practices between protected
or non protected areas (Knorn et al., 2012a).
4.2. Capercaillie and tourism
The negative effect of intensive tourism (e.g. ski resorts) on
capercaillie and other bird populations has been reported in many
regions (e.g. Moss et al., 2014; Rösner et al., 2013; Thiel et al.,
2011). Human disturbance may inﬂuence metapopulation dynam-
ics and contribute to genetic impoverishment in small populations
(Moss et al., 2014). For example, collisions with ski-lift cables may
Number of males
10 20 30 40 50 60 0 1 2 3 4 5 0 1 2 3 4 5
Proportion of clearcuts (%) Intensity of tourism Selective logging intensity
e (Prop. of clearcuts | o.v.)
e (Number of males | o.v.)
e (Intensity of tourism | o.v.)
e (Sel. logging intensity | o.v.)
Fig. 2. Partial regression plots (a, b, c) and effect plots (d, e, f) demonstrating the multivariate relationship between number of males in the lek centres and the proportion of
clearcuts (a, d), intensity of tourism (b, e) and selective logging intensity (c, f). Lines represent partial regression slopes (a, b, c) and partial ﬁtted relationships holding the
other variables (o.v.) constant at their means (d, e, f). Ninety-ﬁve percent conﬁdence intervals are shown in grey.
M. Mikoláš et al. / Forest Ecology and Management 354 (2015) 26–34 31
increase capercaillie mortality. Intensive tourism can negatively
inﬂuence brood success because it increases levels of the stress
hormone corticosterone, which inﬂuences reproduction and sur-
vival (Thiel et al., 2011). Also, areas frequented by people have
increased carrying capacity for a family of avian predators – the
Corvidae; ravens, crows and jays favour human inhabited areas
(Storch and Leidenberger, 2003). Recent increased use of snowmo-
biles and off-road vehicles concentrated near tourist recreation
areas may have the most negative effects, as they may cause seri-
ous yearlong disturbances to the capercaillie in many regions. To
offset the effects of tourism on capercaillie populations, sufﬁciently
large habitat patches that provide good hiding cover and buffers
from touristic areas and roads should be established and main-
tained (Newsome and Moore, 2012). Increased use of selective har-
vesting can help to achieve this. Further, by planting dense
vegetation bordering frequented tourist paths, the probability of
people leaving marked trails and disturbing capercaillies would
be reduced (Coppes and Braunisch, 2013).
4.3. Old growth forests as refuge
Old-growth forests are the primary habitats for capercaillies
(Klaus et al., 1989) and it was shown already for the Carpathians
as the main capercaillie habitat type (Saniga, 2003). The habitat
characteristics of most of the studied lek centres were typical of
old-growth forests – large amounts of dead wood, elevated root
plates, multi-cohort open canopy stands, etc. (Table A1). The struc-
ture of these forests is a result of natural disturbance regimes char-
acterized by windthrows and bark beetle outbreaks, which are
usually infrequent, moderate- to high-severity disturbances that
inﬂuence forest structure across all spatial scales – tree, stand,
and landscape (Svoboda et al., 2014; Trotsiuk et al., 2014). These
disturbances create canopy gaps and forest edges of different sizes
(Fraver and White, 2005), which provides suitable habitats for
capercaillie. These types of stands are currently just a small frac-
tion of the landscape in central Europe (Wesolowski, 2005), thus,
they play a key role for the preservation of capercaillie populations
and many other species in the Carpathians. There has been a clear
trend in the large-scale destruction of mountain spruce forests,
including old-growth and natural forests across the whole
Carpathian region over the past few decades (Grifﬁths et al.,
2014; Knorn et al., 2012a,b; Kuemmerle et al., 2009, 2007), and
the natural mountain forest community is endangered. The
long-term survival of the species is therefore reliant on the viabil-
ity of core areas to serve as refuges.
5. Conclusions and implications for forest management
Our study indicates that extensive human land use, such as low
intensity selection harvesting, can have positive effects on caper-
caillie, but large-scale clearcutting and intensive tourism can also
have very negative effects. Measures to conserve the umbrella spe-
cies capercaillie will beneﬁt a wide range of other forest species
and better preserve a wide range of ecosystem functions and ser-
vices (Balvanera et al., 2006; Suter et al., 2002). Our results indicate
that even protected areas do not ensure the protection of threat-
ened species and their habitats in the Carpathian region
(Table 1). This can only be changed if the priority in protected areas
is the conservation of biodiversity and prioritization of
non-extractive ecosystem services rather than timber production
as in typical commercial forests.
Conservation and forest management goals should be based on
a multi-scale approach. Commercial forest management in rele-
vant areas should be modiﬁed to emulate natural disturbance pro-
cesses across multiple scales. With single-tree selection, group
selection, conversion of spruce to mixed species, increasing large
snag densities, and creating a multi-layered canopy at the stand
level, foresters can accelerate the development of suitable natural
forest habitats (Franklin et al., 2002). Sufﬁcient areas (cca
) of quality habitat are necessary foundations for viable
capercaillie populations (Grimm and Storch, 2000), thus, manage-
ment planning for viable populations should be in accordance with
broader relationships at the landscape scale to ensure a
sufﬁciently-sized mosaic of suitable habitats and connectivity
between habitat patches (Graf et al., 2009; Segelbacher et al.,
2003). To ensure the long-term survival of capercaillie populations
in the Carpathians, it is necessary to conduct further assessments
of the suitability of existing capercaillie habitats (e.g. create a habi-
tat suitability model) and identify the optimal extent of suitable
habitat and its connectivity (Braunisch and Suchant, 2008). The
habitat suitability model should be adapted regionally, because
species – habitat relationships may differ between regions, due
to different site conditions, vegetation types, and successional pro-
cesses (Graf et al., 2005), as exempliﬁed by differences in capercail-
lie habitat use in Norway and central Europe. Management at the
landscape scale should include the protection of old-growth for-
ests, the restriction of fragmentation and large-scale deforestation,
to ensure a more ecologically sustainable forestry model in central
This study was supported by Czech Science Foundation Project
(GACR 15-14840S) and Czech University of Life Sciences, Prague
(CIGA No. 20154316) and also by German Aerospace Centre –
Project Management Agency (P. J. L., grant number 50EE0949).
We thank Ivana Kalafusová, Ovidiu Ionescu, Tudor Stancioiu, G.E.
Predoiou, the administrations of Natural Park Maramuresß,
National Park Rodnei, National Park Piatra Craiului, National Park
˘limani, Natural Park Bucegi, National Park Ha
of Lunca Bradului for their information and help in collecting data.
We thank Ilse Storch and Mario Quevedo for revising an early ver-
sion of the manuscript.
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