Chornobyl Center for Nuclear Safety, Radioactive Waste and Radioecology

P.O. Box 151, 77th Gvardeiskaya Diviziya St. 11, , Kiev Region, 07101

Assessment of radiation effects in birds breeding in Red Forest area (2003- 2006): problems of research approaches and interpretation of the results

Sergey Gashchak

COMET Workshop, 29.08-1.09.2016, Chernihiv, Ukraine Breeding birds in Red Forest 2003-2006

Main initial idea - to get a sample of breeding birds chronically exposed to radiation in order to sample blood, sperm, feathers, eggs etc. to assess biological effects BUT!!! Occupation of the nest boxes was not a goal of the study, and was not discussed initially

HOWEVER the main conclusion of the article:

“birds prefer to breed in sites with low radioactivity in …” Breeding birds in Red Forest 2003-2006

• >210 NB in Red Forest in 2003 • >70 NB in reference site in 2005 • Dose rate & habitat description • Birds description and marking • Course of breeding 5-200 µSv/hr • Egg morphology 2003-2006 • Live monitoring 137Cs/90Sr • Sampling eggs, blood, feathers 0.8-2 µSv/hr 2005-2006

2003-2004 in partnership with Un. of Columbia 2005-2006 independently Breeding birds in Red Forest 2003-2006

>200 µSv/h

In Red Forest area – very uneven radiological conditions 5-7 µSv/h Breeding birds in Red Forest 2003-2006

Pine forest

Bands of 20-30 y.o. Dead pines, birch/aspen` young sparse birch/aspen reforestation, dry meadows

Birch, aspen, alder, wet Pine forest` meadows Breeding birds in Red Forest 2003-2006 Distinct on qualities habitats were in base of this field experiment

Sparse birch forest Pine forest

Dead pines, young sparse birch/aspen reforestation, dry meadows Breeding birds in Red Forest 2003-2006

2003 New-built nest-boxes and late (April) installation caused low rate of occupation 13.1% nest boxes Breeding birds in Red Forest 2003-2006

2004

Hazel dormouse – main enemy of birds in Red Forest Occupation Birds – 20.1% Dormouse – 17.7% Breeding birds in Red Forest 2003-2006

2005

Occupation Birds – 18.4% Dormouse – 23.1%

underflooding Breeding birds in Red Forest 2003-2006

2006

Occupation Birds – 16.9% Dormouse – 13.6%

underflooding Breeding birds in Red Forest 2003-2006

2003-2006 Occupation looks like: • Great tits do not avoid to nest in high contaminated areas • Dormouse lives almost only in high contaminated areas • Pied flycatcher strongly prefer ‘cleaner’ locations

… if do not consider quality of the habitats!!! Breeding birds in Red Forest 2003-2006

• Occupation follows pattern of habitats and corresponds to 2003-2006 biological preferences (abilities) of the birds • Great tits inhabit almost all habitats with available holes • Dormouse prefers deciduous woods with undergrowth • Pied flycatcher prefers mature pine forest Breeding birds in Red Forest 2003-2006

Conditional control site (0.8-2.5 µSv/hr) • Almost only - mature pine forest • High rate of occupation (57-74%) from the very beginning • Almost all inhabitants (93-100%) - birds • Higher diversity of species on the second year • Pied flycatchers – a little more than great tits • Strong competition, sometimes extrusion of tits by flycatchers • No regularities in spatial distribution 2005 2006 Breeding birds in Red Forest 2003-2006 Main results of multi-factorial variance analysis • At the given design no reasons to state ‘birds prefer to breed at low radioactivity’ since quality of habitats strongly correlates with contamination, and vice verse • Pied flycatchers prefer mature pine forest rather sparse birch reforestation • Great tit has a little larger preference of deciduous forests including sparse • Course of breeding does not depend on radioactivity • Final success of breeding doesn’t depend on radioactivity • Almost all cases of egg/nestling death were caused by human activity, predators or competitors • There are unknown factors (e.g. age of female, homing) which have stronger influence on occupation, preferences and breeding success than the factors assessed Breeding birds in Red Forest 2003-2006 Dose-effect observations 36 (L  D) V  100% 12,0 D 34 D 11,6 11,2 32 L 10,8 10,4 30

Elongation 10,0

28 clutch in eggs Number 9,6

9,2 26 0 20 40 60 80 100 120 0 20 40 60 80 100 120 Dose rate, Sv/hr Dose rate, Sv/hr • Elongation index of eggs (V, %) • Variability of clutch size shorten following radiation - they significantly grew with became more spherical radiation Breeding birds in Red Forest 2003-2006 Dose-effect observations • Remarkable increase of abnormal blood cells in comparison with birds of control area

24

20

16

% 12

8

4

0 Control (0,12) RF (6,6) RF (46,7) RF (89,0) Erythrocytes with vacuoles

24 30

20 25

16 20

% 15

% 12

8 10

4 5

0 0 Control (0,12) RF (6,6) RF (46,7) RF (89,0) Control (0,12) RF (6,6) RF (46,7) RF (89,0) Erythrocytes with karyorrhexis Abnormal leucocytes Breeding birds in Red Forest 2003-2006 Lessons and conclusions • Red Forest site is very specific area on natural conditions. If radiation effects are main study subject researchers have to be very thorough in choice of reference sites and study objects in order to exclude influence of non- radiation factors • In the given case the experimental design had to include either only areas with similar sparse birch forests and different radioactivity or pairs ‘habitat/radioactivity’ • ‘Pure’ statistic analysis of data obtained in studies with wrong design/approaches can lead to wrong conclusions • Live system like ‘breeding birds /habitats’ on particular territory is very changeable over years. There is high risk of fault if researcher ignores long- term processes in populations and ecosystems • Radioactivity of the Red Forest site is still able to cause ‘visible’ biological effects. We have to be very competent in choice of study objects and methods. Thank you for your attention!