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Rückgang von Bestand und Verbreitung des Auerhuhns Tetrao urogallus im Schwarzwald - Decline in Capercaillie Tetrao urogallus numbers and distribution area in the Black Forest.

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Decline in Capercaillie Tetrao urogallus numbers and distribution area in the Black Forest. Ornithol. Beob. 113: 235–248. Even though Capercaillie are still present in large parts of its original range, its numbers have decreased in many parts of the Western and Central European range and in several cases, local populations have gone extinct. The Capercail-lie population in the Black Forest, SouthWestern Germany, has undergone drastic declines in the past decades. In 1971 the number of male Capercaillie displaying at lekking sites throughout the Black Forest was counted for the first time, and since 1983 counts have been performed on a yearly basis. From 1993 onwards, all sightings and signs of Capercaillie presence have been documented and combined to create a distribution map, which is updated every five years. The lek-counts show fluctuations in the number of displaying males, but with a strong decline becoming evident over the entire study period: whereas roughly 450 males were counted between 1983 and 1994, the last count in 2016 revealed only 206 males. The decline was paralleled by a decline in range from 607 km 2 in 1993 to 457 km 2 in 2013. This 25 % decline is not evenly distributed in the Black Forest but is largest in the Southern and Eastern Black Forest («Süd-Schwarzwald» and «Baar-Schwarzwald») compared to the sub-populations in the Northern and Central parts of the study area. Possible causes include: habitat loss and deterioration, climate change, anthropogenic disturbance and increasing numbers of predators, most likely several of these operating in conjunction.
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Der Ornithologische Beobachter / Band 113 / Heft 3 / September 2016 235
Rückgang von Bestand und Verbreitung des Auerhuhns
Tetrao urogallus im Schwarzwald
Joy Coppes, Judith Ehrlacher, Gerrit Müller, Klaus Roth, Karl-Eugen Schroth, Veronika Braunisch
und Rudi Suchant

&Tetrao urogallus
 

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         
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           
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  
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2   2   
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


         
       
  

 
       

        
        

  Tetrao urogallus   
    
     
  
      
    
      
   
    
     
236  

     
     

     
     
 
     
 


       

    




     

   
 

     
     
      
 
      
    
      
      
    
     
    

      
    
   
    
   
   

      
     

    

      
  
    
     
 


     
      




    
   
      


 
     
     
    
     
    
      
    
 
   

 

    
     
 
  

    
 

1. Untersuchungsgebiet, Material und
Methode
1.1. Untersuchungsgebiet und Auerhuhnschutz
Untersuchungsgebiet: 

 
    
     

     
     
  

     
    
     
 

   
   
   
      
      
   
     
     
     

     

    
    
  
    
    
  
  
    
     

  

Auerhuhnschutz im Schwarzwald: 
   
     
   
Abb. 1.

×





Capercaillie distribution in 2013,
shown in 3×3 km grid cells in the
four parts of the study area («Nord»
= north, «Mitte» = central, «Süd» =
south, and «Baar»). The shading in-
dicates the percentage of the grid cell
occupied by Capercaillie.
  




  
   
      

  
    
     
     
   
     
   
     
    

    


1.2. Datenerhebung
1.2.1. Populationstrend, Balzplatz-Monitoring
     
    
       
     
    
     

      

     
  
     
     
     
    
 



      

     
       
     
  
      
  


     
 
    
Abb. 2.




Their brown feathers
make the Capercaillie
females very well ca-
mouflaged.
  
      

 
    

       

   
     

     




     
   

  
 


 




 

1.2.2. Verbreitungsgebiete
    
    
  
   

    
   
     
     
     
   
     
     

     
  
   
 
     
   
    
     
 
   
     
   
 
Abb. 3.




The male Caper-
caillie is much more
conspicuous compared
to the female.
  
      

   
     
  
 
     
     


     
   
       
  
      

    


     
     
      


   



 
      
      
  


 

2. Ergebnisse
2.1. Bestandstrend nach den Ergebnissen des
Balzplatz-Monitorings
     

   
    
   
 
     

Abb. 4.      


Num-
ber of Capercaillie males counted at the leks in the Black Forest. The first count was carried out in the year
1971, since 1983 this was done every year. In 2013 a reliable count was not possible due to adverse weather
conditions. The countings are organized by the hunter’s associations: «Auerwildhegegemeinschaft» and the
Auerwildhegeringe «Freudenstadt» and «Calw».
  
    
      

    
       
      

     
         
      



      
     
      
      
     
    


       

     
Abb. 5.







The number
of males counted every
fifth year at the leks in
the four different parts
of the Black Forest.
As in 2013 a reliable
count was not possible
due to adverse weather
conditions, the data of
2012 are shown here.
Abb. 6.











An open
pine forest with blue-
berries in the northern
Black forest, the rich
ground vegetation pro-
vides cover and food
for the adult birds. Due
to the warmth there
are many insects as an
important resource for
the young birds.
  
 
        
 
      

2.2. Verbreitungsgebiete
       
     
     
 
     
        
 
     
   
     
     
     
     
  
     
 
  

      

Abb. 8. 





The area in-
habited by Capercaillie
per year, illustrated for
each part of the study
area (Nord» = north,
«Mitte» = central,
«Süd» = south, and
«Baar») and the total
area («Gesamt»).
Abb. 7.







Mean
number of males per
lekking site (± standard
deviation) in the four
parts of the study area.
Below each column the
number of lekking sites
is indicated.
  
   
      
       
     
      
2     2  


      2 
     
     
 
 2 
     


 



3. Diskussion
3.1. Datengrundlage
      
 
      
  
 




    
    
    


      
 
   

    
      
      
    


     
     

3.2. Bestandsrückgang


     

     
Abb. 9.







Change in per-
centage of the area in-
habited by Capercaillie
since 1988– 1993 per
year illustrated for the
four parts of the study
area («Nord» = north,
«Mitte» = central,
«Süd» = south, and
«Baar») and the entire
Black Forest («Ge-
samt»).
  
      

     
       
 
       
   
      

   
     
   
 

     
  
      
     
      
   
    
 
       
  
    

      

     
 
   
      
  
     

        
     
     

    
 
 
      
  

  

3.3. Potenzielle Rückgangsursachen
   
    
      
    

    
      
      
       
      

     
 
      
    
    
     
 
   


 
      
    
 
 
     
    
     
    
     
Abb. 10.       
 
 For the survival of
the population the raising of Capercaillie chicks is
essential.
  

 
    

    

  
  
     

      

    
    Vu l-
pes vulpes  Accipiter gentilis 
      


       
   
     
    
      
    

    
    
 
      
    


      
 
    
 
 



3.4. Fazit
    

    


    
     
   
 

      
   


Dank.    
     
  
   
     
     
    
     
     
     



  

 
     


Zusammenfassung, Résumé
Tetrao urogallus
  
Abb. 11.
   
      
     
 Both integrated within normal forestry
as well as with specific measures, one can improve
capercaillie habitats.
  



 
 
     
     

 
      
 


 
  

       
     
     

  2      
 2     
   

     

    
  


Régression de l’effectif et de l’aire de répartition
du Grand Tétras Tetrao urogallus en Forêt Noire
  Tetrao urogallus  
         
      
       

      
    
  
 
         
    
      
     
 

       


   
        

     
       
  2     2   

      
   

        
      
     
 


Literatur
       
   &  
(1   
   
    
  

  &


    &   
   
       
     

    &   
    
 
   




  (2 Tetrao urogallus 


&
 Tetrao urogallus   
   


  &    
   
 


  &    
     
     
     

&
(2 



&   
    

  
&  
      
 
   Tetrao urogallus
 
  &    
Tetrao urogallus


  &     
     
(Tetrao urogallus    
   
      
      

&
       
Vulpes vulpes


    

  &     
        

&

    

   
 

        & 
     
  

Tetrao urogallus





(2
    
    
   
   
 

  
&

    
    

        &


&
  
Tetrao urogallus
  


&   

 
 

    
    


       
 &  


& 
    
    
    
   

      
    
      

  
     

&Tetrao urogallus
   
    

&  
Tetrao uro-
gallus

      

&
      



  &     
 


      
Tetrao urogallus

      &  
(2  Tetrao urogallus 


      

&
 Tetrao uro-
gallus   
   

  
      


  
Tetrao
urogallus
   Tetrao urogallus 

  
  

  & 



    &    
    
Accipiter gentilis  
   

  &    
 
     
    
   


       
&       
     

&
(2Tet -
rao urogallus

&
(Tetrao urogallus 
    


&   
 
Tetrao urogallus

&  
Tetrao urogallus

& 

 
&  
      

& 
     
   

Manuskript eingegangen 4. März 2016
Bereinigte Fassung angenommen 31. Mai 2016
  
 Tetrao urogallus 
Tetrao tetrix
       
 


&
   Tetrao urogallus 



&  



        
    
       

  

  

&
     
        
 &  

 
  

&
      


&



Tetrao urogallus 


     

& 
Tetrao urogallus

     
  


       





Tetrao urogallus

      
       
... ornithologists, hunters and forestry personnel) to ensure capercaillie were present. The study areas represent a large range of habitat conditions, landscape configurations, and population states: In the Black Forest, a lower mountain range, the capercaillie population is highly fragmented (Braunisch et al., 2010) and has been decreasing over the past decades (Coppes et al., 2016). In the Bavarian study area, located on the edge of the larger Alpine distribution of capercaillie, population numbers are also declining (xy unpubl. ...
... sand-baths) and verified by a team of capercaillie experts. Capercaillie droppings can be found over longer time periods after defecation (Poggenburg et al., 2018) and searching for indirect signs of presence is an established method to study capercaillie occurrence (Coppes et al., 2016) and habitat use (Summers et al., 2007;Moss et al., 2014;Zohmann et al., 2014). Before sampling, all field assistants were trained in habitat assessment, capercaillie ecology, and in the identification of indirect capercaillie signs to ensure consistency and high data quality. ...
... differences between areas might also be explained by large-scale landscape effects: whereas the German study areas were located in fragmented forest landscapes (Storch, 2007;Coppes et al., 2016), the Austrian study areas were mostly located in continuous forest landscapes and at higher altitudes with colder and therefore climatic conditions more favourable for capercaillie . Due to our consistent results across this large geographical range as well as time span, we are confident that our results are widely applicable. ...
Article
Outdoor recreation activities are growing in popularity, causing increasing pressure on wildlife. There are various ways in which wildlife reacts to recreation activities, ranging from behavioural to physiological responses, with regional variation in response-intensity within the same species. We tested whether the effects of human recreation are modulated by overall structural habitat suitability, using a model that included vegetation and topography, at both the regional and local habitat use scale. By undertaking a systematic, plot-based survey over 13 years in 13 study regions across central Europe, we studied how recreation infrastructure and habitat suitability interact and affect the variation in regional densities and local habitat use of an endangered model species: the western capercaillie (Tetrao urogallus). Both regional densities and local habitat use varied greatly between study years and regions. Capercaillie densities were positively correlated with average habitat suitability, but significantly reduced when over 50% of the area was influenced by recreation activities. Habitat suitability was the main predictor determining local habitat use. Recreation infrastructures were avoided: the effect being stronger in poor habitat conditions, while slightly mediated by high habitat suitability. Our results indicate that effects of recreation activities might be mitigated by improving habitat suitability; however this has limits because it only affects local scale habitat use but not regional densities. We stress the importance of recreation-free areas which must cover extensive (i.e.>50%) parts of the species range.
... declining and isolated populations (Segelbacher et al. 2003, Storch 2007, Coppes et al. 2015. The Black Forest capercaillie population is the largest central European population outside the Alps, but is isolated from other populations in Europe (Segelbacher et al. 2003) and highly fragmented (Braunisch et al. 2010, Coppes et al. 2016. Based on annual counts at the leks, the population is estimated at about 400 to 500 individuals (Coppes et al. 2016) which roughly corresponds to the estimated minimum viable population size as calculated by Grimm and Storch (2000). ...
... The Black Forest capercaillie population is the largest central European population outside the Alps, but is isolated from other populations in Europe (Segelbacher et al. 2003) and highly fragmented (Braunisch et al. 2010, Coppes et al. 2016. Based on annual counts at the leks, the population is estimated at about 400 to 500 individuals (Coppes et al. 2016) which roughly corresponds to the estimated minimum viable population size as calculated by Grimm and Storch (2000). Over the last 30 years capercaillie numbers have rapidly declined by about 65% (Coppes et al. 2016), which resulted in being red listed as 'endangered' in the state of Baden-Württemberg (Hölzinger et al. 2007). ...
... Based on annual counts at the leks, the population is estimated at about 400 to 500 individuals (Coppes et al. 2016) which roughly corresponds to the estimated minimum viable population size as calculated by Grimm and Storch (2000). Over the last 30 years capercaillie numbers have rapidly declined by about 65% (Coppes et al. 2016), which resulted in being red listed as 'endangered' in the state of Baden-Württemberg (Hölzinger et al. 2007). ...
... EV-3 declining and isolated populations (Segelbacher et al. 2003, Storch 2007, Coppes et al. 2015. Th e Black Forest capercaillie population is the largest central European population outside the Alps, but is isolated from other populations in Europe (Segelbacher et al. 2003) and highly fragmented (Braunisch et al. 2010, Coppes et al. 2016. Based on annual counts at the leks, the population is estimated at about 400 to 500 individuals (Coppes et al. 2016) which roughly corresponds to the estimated minimum viable population size as calculated by Grimm and Storch (2000). ...
... Th e Black Forest capercaillie population is the largest central European population outside the Alps, but is isolated from other populations in Europe (Segelbacher et al. 2003) and highly fragmented (Braunisch et al. 2010, Coppes et al. 2016. Based on annual counts at the leks, the population is estimated at about 400 to 500 individuals (Coppes et al. 2016) which roughly corresponds to the estimated minimum viable population size as calculated by Grimm and Storch (2000). Over the last 30 years capercaillie numbers have rapidly declined by about 65% (Coppes et al. 2016), which resulted in being red listed as ' endangered ' in the state of Baden-W ü rttemberg (H ö lzinger et al. 2007). ...
... Based on annual counts at the leks, the population is estimated at about 400 to 500 individuals (Coppes et al. 2016) which roughly corresponds to the estimated minimum viable population size as calculated by Grimm and Storch (2000). Over the last 30 years capercaillie numbers have rapidly declined by about 65% (Coppes et al. 2016), which resulted in being red listed as ' endangered ' in the state of Baden-W ü rttemberg (H ö lzinger et al. 2007). ...
Article
Full-text available
Outdoor recreation inflicts a wide array of impacts on individual animals, many of them reflected in the avoidance of disturbed areas. The scale and spatial extent, however, at which wildlife populations are affected, are mostly unclear. Particularly in geographically isolated populations, where restricted habitat availability may preclude a relocation to undisturbed areas, effective habitat reduction may remain underestimated or even unnoticed, when animals stay in disturbed areas and only show small-scale responses. Based on telemetry data, we investigated the spatial and seasonal effects of outdoor recreation - in relation to landscape and vegetation conditions - on western capercaillie Tetrao urogallus, considering two scales, home range and within-home range habitat selection. We determined the distance-thresholds up to which recreation infrastructures were avoided and estimated the extent of affected habitat for the isolated Black Forest (southwestern Germany) study population. While outdoor recreation did not affect home range selection, strong effects on habitat use within the home range were detected: distance to recreation infrastructure (hiking and cross-country skiing trails, ski pistes) was the main determinant of habitat selection in winter; in summer, mountain bike trails and hiker's restaurants were avoided up to an average distance of 145 m (CI: 60-1092 m). Around winter-infrastructure, relative avoidance was recorded up to 320 m (CI: 36-327 m), it was reduced, however, when dense understory provided visual cover. Of the entire population area, between 8-20% (summer) and 8-40% (winter) were affected by outdoor recreation, mainly in the high altitudes. Even without evident large-scale shifts in species distribution, local-scale avoidance of outdoor recreation can substantially contribute to effective habitat reduction. Based on our results we recommend a general reduction in recreation infrastructure density in key habitats, the establishment of undisturbed wildlife refuges with a diameter of at least 800 m, as well as enhancing visual protection by maintaining a strip of dense understory along trails.
... The Black Forest holds one of the largest capercaillie populations in central Europe, outside the Alps (Segelbacher, Höglund, & Storch, 2003;Storch, 2007), a species inhabiting well-structured, open mountain and boreal forests (Graf, Mathys, & Bollmann, 2009;Klaus et al., 1989;Storch, 2002). The Black Forest capercaillie population is isolated from other populations in central Europe (Segelbacher et al., 2003) and highly fragmented (Braunisch, Segelbacher, & Hirzel, 2010;Coppes et al., 2016). Population size and distribution have been continuously decreasing over the last 30 years (Coppes et al., 2016), with the cause considered to be multifactorial, including habitat deterioration (Suchant & Braunisch, 2004), habitat fragmentation (Braunisch et al., 2010), predator abundance (Kämmerle et al., 2017), disturbance through human recreation as well as climate change (Braunisch et al., 2013;Huntley, Green, Collingham, & Willis, 2007). ...
... The Black Forest capercaillie population is isolated from other populations in central Europe (Segelbacher et al., 2003) and highly fragmented (Braunisch, Segelbacher, & Hirzel, 2010;Coppes et al., 2016). Population size and distribution have been continuously decreasing over the last 30 years (Coppes et al., 2016), with the cause considered to be multifactorial, including habitat deterioration (Suchant & Braunisch, 2004), habitat fragmentation (Braunisch et al., 2010), predator abundance (Kämmerle et al., 2017), disturbance through human recreation as well as climate change (Braunisch et al., 2013;Huntley, Green, Collingham, & Willis, 2007). ...
Article
1. As a non-invasive and inexpensive method, the use of faecal glucocorticoid metabolites (FGM) analysis in wildlife research is increasing. Various environmental factors have been shown to influence FGM levels, or faecal corticosteroid metabolites (FCM) levels in birds, but most studies do not account for inter-individual variance, which we hypothesised may substantially affect results. 2. We combined FCM analysis with genetic analysis to identify the sex and individual's identity in samples collected in three consecutive winters; with repeated samples per individual, across the entire range of an endangered population of capercaillie (Tetrao urogallus) in Southwestern Germany. Using generalized additive mixed models, we modelled FCM levels as a function of sex, season and environmental covariates at two spatial scales: location and home range. We compared two models: one including information on the individual animal, and the other excluding this information (i.e. naïve model) to assess the influence of individual heterogeneity on the results obtained. 3. Models accounting for inter-individual differences explained 44.0% and 45.1% (at the location and home-range scale respectively), while only very little (4.0% and 5.1%, respectively) was explained by the environmental predictors. When ignor- ing individual effects, the model results changed considerably with other, previ- ously non- informative predictors, becoming significant. 4. In the full models, accounting for inter-individual variance, weather conditions had no effect at either scale. FCM levels were negatively correlated with habitat quality at the sampling location, while human recreation at the home range scale led to elevated FCM levels. In the naïve models, two additional predictors appeared significant: one weather variable at the local scales and two at the home range scale. In all models, seasonal FCM patterns differed significantly between males and females. 5. Synthesis and applications. By combining faecal corticosteroid metabolites (FCM) analysis with genetic individual assessment we demonstrate that individual heterogeneity can explain most of the variance in FCM levels and that ignoring this information can lead to erroneous conclusions when testing for environmental stressors. We therefore stress the importance of identifying individuals when studying FCM in wildlife and recommend combining FCM analyses with genetic analyses to adequately address this issue. This article is protected by copyright. All rights reserved.
... Due to its large distribution range, it is not globally endangered (BirdLife-International 2012). However, many populations are decreasing in Central Europe, resulting in endangered local populations (Storch 2007;Coppes et al. 2016) and making it a relevant species for species protection programs (Braunisch and Suchant 2013). Due to its elusive behavior, the main method to address capercaillie's occurrence is searching for indirect signs, which include tracks, sand baths, feathers, and droppings (Klaus et al. 1989). ...
Article
Full-text available
Feces of wildlife species are commonly used indicators for species’ presence or relative abundance. These might however be biased due to inconspicuousness, due to rapid decay and disappearance, or due to high site-dependent variance in decay dynamics. Mapping of indirect signs is a frequently applied approach to study habitat use or distribution of grouse species. However, only a few studies addressed avian dropping decay up to now, and no study focused on dropping decay of European grouse species. Consequently, we conducted field surveys and greenhouse trials, studying time spans over which capercaillie (Tetrao urogallus) droppings persist and factors influencing the decay rates (i.e., habitat type, small mammal access, and precipitation regime). In the field survey, after an exposure of 98 days, only 6% of droppings (n = 156) decayed completely and most droppings remained nearly unchanged. The decay rate was influenced by microsite conditions (i.e., vegetation and location), with lowest decay rates in areas with little ground vegetation or on tree stubs. Destruents were not found to play a major role in affecting decay rate. The greenhouse trial revealed the impact of precipitation on the decay rate of droppings (n = 400): under high-amount and high-intensity precipitation regime droppings decayed faster compared to low-amount and low-intensity precipitation. The slow decay rate, and resulting long time period that they can be detected, therefore means that capercaillie droppings are a valid proxy for species’ occurrence.
Thesis
Human outdoor recreation activities (i.e. hiking, mountain biking, cross-country skiing) are increasing in numbers, and are economically important in many parts of the world, including the Black Forest. These recreation activities exert pressure on the ecosystems in which they take place and in many cases are a threat to a variety of wildlife species. There are many ways in which wildlife can be impacted by outdoor recreation and tourism: often species react to the presence of humans in a similar way as to the presence of predators, resulting in anti-predator responses. The increase in recreational activities therefore causes an increase in anti-predator costs for wildlife. Some species are attracted to human recreation activities and others have been shown to habituate to human presence, resulting in reduced reactions to humans over time. There are however increasing number of studies indicating negative effects of recreation activities on wildlife. The effects range from fleeing, to changes in vigilance behaviour and reduced use of areas which are intensively used by recreational users (i.e. close to infrastructures such as hiking trails or skiing slopes). Recreation activities have also been linked to changes in bird species composition, reduced densities, and reduced breeding success. Physiological effects include an increased heart rate and increased stress hormone levels in areas close to recreation infrastructure. Previous studies however also revealed that the response wildlife to recreation activities might vary between species, areas and habitats. To provide both possibilities for recreation activities as well as to avoid negative effects on biodiversity, it is important to know the type, extent and source of variation to design effective conservation measures. Using two model species, red deer (Cervus elaphus) and capercaillie (Tetrao urogallus) I studied how the response of wildlife to recreation activities varies under different environmental conditions. From the results I derived management options to mitigate the effects of recreation activities. In the first chapter I analysed GPS telemetry data of red deer to reveal how they have adapted to the diurnal rhythm of recreationists in their habitats. During the day, when recreationists are present, red deer avoid areas close to the recreation infrastructure, however during night, when no recreationists are present; the deer even prefer these areas. This indicates that the deer have temporally adapted their behaviour to avoid human recreationists. At the same time, I was able to show that the deer preferred to use the wildlife refuges (i.e. areas in which recreational activities are prohibited), compared to other management areas. In the second chapter I studied how capercaillie spatially avoided recreational infrastructure in the Black Forest, using radio telemetry. The birds showed reduced use of areas close to recreation activities all year around, with higher avoidance distances in winter (320 m) compared to summer (145 m), resulting in an effective habitat reduction. By including detailed vegetation data in the analysis, I showed that this avoidance distance is reduced when a dense shrub layer is present, i.e. when the hiding possibilities are better. When extrapolating the area affected by recreation infrastructure (within the avoidance distances) to the entire capercaillie distribution in the Black Forest, I revealed that a large fraction of the current capercaillie distribution (i.e. up to 20 % in summer and 40 % in winter) is potentially disturbed by recreational activities. This indicates that local-scale avoidance of recreation infrastructure is likely to cause habitat deterioration on a large scale, possibly negatively affecting the capercaillie population in the Black Forest. By combining the analysis of faecal corticoid metabolites (FCM) with genetic analyses of capercaillie droppings, I was able to reveal the importance of including information on individual heterogeneity in stress responses when studying the effects of recreation activities on wildlife (chapter three). When comparing generalized additive models which included the information on individual heterogeneity (as a random effect) with those not including this information I showed that the results differed greatly. The models without including the data on individual heterogeneity explained only very little (4.0 % and 5.1 %) of the observed variation in FCM-levels. When including the data on individual heterogeneity the explained variation increased significantly (44.0 % and 45.1 %). At the same time the results of the models changed with additional predictors explaining elevated FCM levels appearing significant. The distance to recreation infrastructure was significantly affecting the FCM-levels, with higher FCM-levels close to recreation infrastructure. In this chapter I have demonstrated that individual heterogeneity can explain most of the observed variance in FCM levels and that ignoring this information can lead to erroneous conclusions. In the fourth chapter I combined data from 13 different study areas to evaluate the effect of structural habitat suitability (HSI) on the response of capercaillie to recreation activities on local habitat use, as well as regional population densities. Data on structural habitat parameters and capercaillie habitat use (i.e. droppings, feathers) were collected on sample plots. The probability of finding a capercaillie sign on a plot was positively correlated with the HSI. This probability however was reduced close to recreational infrastructure. Interestingly I found an interaction between the HSI and distance to recreational infrastructure on the local habitat use scale: the avoidance of recreational infrastructures was stronger in poor habitat conditions compared to highly suitable habitats. The regional capercaillie density was also positively correlated to the average HSI in an area, however significantly lower densities were found when over 50 % of the area was potentially influenced by recreation activities. On this scale however, no interaction between the average HSI and recreation infrastructure was found. Increasing the structural habitat suitability might therefore reduce negative effects of recreational activities on a local habitat use scale, but not on a population scale. The fact that I found a threshold, indicates that capercaillie can cope to some extent with recreational activities, however when this threshold is exceeded, there are negative effects on the population. The last chapter synthesizes the results of the previous chapters and shows how these can be applied to mitigate negative effects of recreation on wildlife and systematically designate wildlife refuges, using the example of capercaillie. By applying different research methods, study designs and analysis, my doctoral thesis reveals how the response of wildlife to recreational activities can vary temporally, seasonally, between individuals and under different habitat conditions. I was able to not just generate new insights which are relevant for future researchers in the field of recreation ecology, but also provide results which can be practically applied by practitioners managing nature areas.
Technical Report
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In-person counts of sage-grouse at leks are vital for informed sage-grouse management, but conducting these counts can be logistically difficult. Camera traps (i.e. automated trail or wildlife cameras) have been used in conjunction with numerous studies of wildlife species, but rarely on grouse leks. In a pilot study, we deployed five camera traps at known leks in central Wyoming over an approximately 10-day span. These cameras successfully captured images of sage-grouse using both ambient illumination and with the aid of built-in infrared flash. Grouse were visible almost every evening at all leks, and less commonly around midnight and after. We conclude that camera traps can be an effective tool when used in a targeted manner for documenting the presence of birds at leks. Further research is needed to develop methodology to achieve counts that are comparable to in person counts by human observers. Additionally, the frequent evening lek attendance we observed could indicate the occurrence of critical breeding behaviors at this time; therefore, future efforts to control disturbance at sage-grouse leks may need to consider at dusk activity as well as dawn.
Article
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Mammalian generalist mesopredators can reach high densities in forest–farmland mosaic landscapes in the absence of top-down control. The abundance of generalist mesopredators is a potentially limiting factor for prey populations, especially ground breeding birds such as grouse. High mesopredator abundance has been associated with reduced reproductive success in grouse. There is little evidence, however, on how variation in mesopredator abundance affects grouse population trends while considering other environmental covariates. We make use of range maps spanning two decades (1993–2013) of a locally threatened capercaillie (Tetrao urogallus) population in the Black Forest, Germany, to assess whether range loss of grouse in forest–farmland mosaic landscapes can be explained by a gradient in red fox abundance, while accounting for other potential determinants of grouse range loss. We show that capercaillie range persistence was favored by increasing snow cover, decreasing index of red fox abundance, slightly increasing index for soil quality, and increasing population connectivity. Red fox abundance had the largest relative impact in areas already facing an elevated capercaillie extinction risk due to unsuitable site conditions, dense forests, or lack of connectivity, but the negative effect was compensated under otherwise optimal conditions. This indicates that the relative importance of predator abundance for prey population dynamics is mediated by environmental attributes, emphasizing the threat to remnant populations but also indicating potential for species conservation.
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