Foundation for nature project development
dr. Rimgaudas Treinys
Lesser Spotted Eagle in Lithuania: ecology, threats and conservation insights 2013-10-31
ProjektÄ… finansuoja
Presentation content
I part –Lesser Spotted Eagle in Lithuania II part – theoretical ground for conservations III part – limitations and threats IV part – insights in conservation
LSE in Lithuania – numbers 1 - No syste ati resear hes efore
’s
- Local researches based on nest search since 1990
- Since 1994 progressively increase in population estimation/ guesstimation 1500
900 - 1200 1000
700 - 1000 500 - 750 500
300 - 500
Solitary pairs 0 1980
1994
1996
1998
2001
LSE in Lithuania – numbers 2 Period: 2000- 2008 Methods: counting / nest search
10 km
“tudy plot i
’s Area: 13 study plots Random borders (1,300 sq.km)
Results: Mean 4 pairs / 100 sq. km range 1 – 9 pairs
Estimated population size 2,400 pairs (range 1,900 – 2,900)
LSE in Lithuania – numbers 3 LIFE+ project: 2011-2013 Methods: counting / nest search
Within project area: another set of 13 study plots Density: range 3 – 16 pairs, mean 8.8 / 100 sq.km Population could be near / over 3,000 pairs
LSE in Lithuania – productivity - Mean productivity 0,58 juv / pair present (2001 – 2008) - Between years fluctuate; range 0.29 – 0.81 juv / pair present
- 2011 – 2012 – productivity higher than average
0.81 0.77
0.71
0.7 0.59
0.43 0.36 0.29
2001
2002
2003
2004
2005
2006
2007
2008
LSE in Lithuania – diet -Rodents, amphibians, other small mammals and birds
- Switch on alternative prey when rodents decrease
(if territory support different habitats providing alternative prey)
LSE in Lithuania – diet & productivity
Productivity positively correlate with share of rodents in diet
Share of rodents
Produktivity of LSE
1 0,8 0,6 0,4 0,2 0
2001
2002
2003
2004 Year
2005
2006
LSE in Lithuania – main feeding habitats
Crop fields, forest edges etc
Meadows, grasslands
LSE in Lithuania – breeding habitats
Forests: gradient from isolated patches to edges of continuous forests tracks
Medynai su lizdais: amžius 30 – 180 (vid. 85) eglė (28%), beržas (20%), plačialapiai (17%), pušis (11%), juodalksnis (10%), drebulė (8%) laikinai užmirkę, užmirkę, pelkiniai – 75% 81% našūs (1a – 2 boniteto)
LSE in Lithuania – nest-site -Avoid pine forests at landscape, nest-stand and nest-tree level - Decidouos, mixed with spruce forest stands, mean age 85 years
Medynai su lizdais: amžius 30 – 180 (vid. 85) eglė (28%), beržas (20%), plačialapiai (17%), pušis (11%), juodalksnis (10%), drebulė (8%) laikinai užmirkę, užmirkę, pelkiniai – 75% 81% našūs (1a – 2 boniteto)
LSE in Lithuania – nest-tree
Spruce 51%
Oak 16%
Birch 16%
Theoretical ground for conservations - Populations are simultaneously regulated by multiple mechanisms through birth and mortality rates
- Intercontinental factor -Key demopgraphic rates for LSE: reproduction (breeding ground)
mortality (ad) (breeding, migr., winter gr.) mortality (first year) (migr.,winter ground)
Limitations / threats for reproduction
- Low reproduction – biological trait
- Reproduction regulated by prey abundace mediated by climate
conditions (Väli 2012)
-Reproduction is spatialy synchronic
over large areas (e.g., Baltic countries; Ü. Väli, U. Bergmanis, R.Treinys, unpubl. results)
Limitation / threats for reproduction – agriculture 1 Large scale socio – economic changes in agriculture practice with opposite directions
Intensification of agriculture in fertile regions Consequences - land use change, decrease in quality, unsuitable crops
Limitation / threats for reproduction – agriculture 2 Abandonment of agriculture in unfertile regions Consequences - overgrowth, loss of open habitats, decrease quality
Limitation / threats for reproduction – forestry 1 Forestry act at different nesting habitat scales I level - forest landscape scale and suitable for nesting patches 10 km
Suitable for nesting patches
230 210
190 170
4 pairs150/ 100 sq.km 130 110 90 70 50 1
6
11
11 pairs / 100 sq.km Pairs / 100 sq.km
G.Mozgeris, R. Treinys, unpubl.results
16
Limitation / threats for reproduction – forestry 2 At forest landscape scale – dynamic of suitable for nesting patches Trend of turnover - decrease by 12% during 2013 – 2023
50 km G.Mozgeris, R. Treinys, unpubl.results
Limitation / threats for reproduction – forestry 3
Next 50 years - decrease of mature forests
Dynamic of mature forest
2013
2018
2023
2028
2033
G.Mozgeris, R. Treinys, unpubl.results
2038
2043
2048
2053
2058
2063
Limitation / threats for reproduction – forestry 4 II level - nest site scale Felling during breeding season in vicinity of nest sites Direct destruction during clear felling
Limitation / threats for reproduction – forestry 5 III level - nest-tree scale Dried, damaged or felt down nest-trees
Limitation / threats for reproduction – forestry 6 IV level - nest support scale Weak branches, lack of horizontality etc.
Limitation / threats for adult mortality 1 -Development of wind energy since 2004 - In 2012 wind energy covered 12% of produced in LT
- Wind energy production concentrated in W Lithuania - Potential for future development in W LT almost depleted
Limitation / threats for adult mortality 2
- Wind energy development started in N LT - Greatest density of LSE in LT: mean 10.9 pairs / 100 sq.km --Suitable patches for nesting distributed over target area
Limitation / threats for adult mortality 3
- Target area support three “PA’s for L“E
- De elop e t of i d far s e e i
i i ity of “PA’s
Insights in conservation
Increase reproduction Conservation strategy Minimize mortality
Conservation assumptions
Lobby at EU and national levels Large population coverage
Insights in conservation : agriculture sector - Not waist funds for reconstructing feeding habitats for several eagle pairs – this not increase reproduction at population level
- Work on socio-economic issues in agriculture sector to look on possibilities how to shape agro-environmental policy at EU and national level
Insights in conservation : forestry sector 1 Wise inventory: - large scale inventory instead fine scale scientific / research based
inventory - state ownership orientated inventory - privet ownership orientated inventory only in areas covered by
compensations for felling restrictions
Insights in conservation : forestry sector 2 Artificial nests
-Recommended as short term measure for improving nest site quality
- Occupation rate ~ 50%
Insights in conservation : forestry sector 3 Need to discuss - how to increase availability of potential nest-trees in younger stands
-LSE built nests in young trees with previously damaged crowns
-Damaging tree crowns in young stands in vicinity of nest sites could be the measure encouraging future nest sites
Insights in conservation : wind energy sector
- Recent threat, need to known sector development extent
- Environmental policy at EU and national level - Close expert level communication to share on knowledge on impact for mortality and solutions - Research and development on mitigation measures
Thanks for attention