The influence of forestry and disturbance on White-tailed ... · PDF fileThe influence of...
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The influence of forestry and
disturbance on White-tailed
eagle breeding success
Tibor Mikuska Croatian Society of Bird and Nature
Protection Szekszard, 17-18 Oct 2011
Acknowledgment
Data also supplied by: Andreja Radović, Valerija Hima (Lonjsko polje) Vlatko Rožac, Boris Bolšec, Sandor Horvat, Hrvoje Domazetović, Stjepan Tkalčec (Kopački rit) Predrag Livak, Tomislav Crnjac, Virna Krpan (Pozesko-slavonska county) Nenad i Mirko Šetina, Vesna Antić, Mario Pavičić (Slavonsko-brodska county) Pavle Dragičević, Stipa Matijašević (Vukovarsko-srijemska county)
Joint HU-HR group (Attila Morocz, Tamas Deme, Lorand Lukacsi et al.)
Threats by country
threats
DE AT SK HU HR RS BG RO
Forestry L ** C M H M H C
Land exploitation L M H L L L H L
River regulation / drainage N L M L H L M H
Disturbance L ** H M M M H C
Reduction of prey base N N U L L C L M
Shooting and trapping N U C L L L M H
Nest robbing N N L L L U L L
Poisoning L H C H U L U H
Lead poisoning * * U M H U U M
Pesticides and pollutants N U U M U M U L
Collision and electrocution L M H M L L U U
Data set & results
Year
Success
Failure
Total
% sucess
% failure
2006 18 7 25 72 28
2007 18 8 26 69 31
2008 12 11 23 52 48
2009 16 10 26 62 38
2010 34 35 69 49 51
2011 36 26 62 58 42
Total 134 97 231 58 42
successful58%
notsuccessful
42%
n = 231
Nesting failures
natural9%
human induced46%
unknown45%
N = 97
Human induced nesting failures
clear cut20%
forestry works62%
hunting9%
disturbance9%
n = 44
Position of the nest
Seven classess In the forest Edge of the
marsh River island Forest w/ road Marsh w/ road Edge of the
clear cut In the clear cut
Probability of nesting failure
Successful Not successful Significance
In the forest (n=53)
29 (55%) 24 (45%) X2 = 21,175 P = 0,0001**
Edge of the marsh (n=69)
48 (70%) 21 (30%) X2 = 4,696 P = 0,0302*
River island (n=7)
5 (71%) 2 (29%) X2 = 0,321 P = 0,5708 NS
Marsh w/ road (n=27)
15 (56%) 12 (44%) X2 = 10,083 P = 0,0015**
Forest w/ road (n=23)
11 (48%)
12 (52%)
X2 = 14,880 P = 0,0001**
Edge of the clear cut (n=20)
10 (50%) 10 (50%) X2 = 11,250 P = 0,0008**
In the clear cut (n=19)
8 (42%) 11 (58%) X2 = 17,053 P = 0,0001**
Protection status
Not protected (n = 68)
successful44%
not successful56%
Nature park (n = 112)
successful58%
not successful42%
Special reserve (n = 51)
successful76%
not successful24%
Definition of intensive forestry
Single species stands
Unified age of the stand
Management recommendations
How many trees / radius should be left?
X
Management recommendations
15-20 trees
X
Management recommendations
100 x 100 m
How many trees / radius should be left? – least number approach – wrong approach
Change from intensive to extensive forestry (PROSILVA forest management)
Strict obedience of nest protection zone during breeding season (300-500 m)
Creation of special reserves – appropriate for eastern European countries
Management recommendations