Transcript Using Birds As Indicators of Biodiversity

An indicator of the impact of
climatic change on European
bird populations
Richard D. Gregory
Stephen G. Willis
Frédéric Jiguet
Petr Voříšek
Alena Klvaňová
Arco van Strien
Brian Huntley
Yvonne C. Collingham
Denis Couvet &
Rhys E. Green
Background
Evidence is accumulating that
climatic change has altered many
biological phenomena across the
globe, including the geographical
ranges and abundance of plants and
animals, and the timing of events in
their lives such as growth,
reproduction and migration
Birds laying earlier - BTO Nest Record Scheme
Leaf burst earlier in Europe
Scientists and policy makers have
called for the development of
indicators of the impacts of climatic
change on biodiversity based upon
these phenomena
Purpose of a climatic change indicator:
To capture biological impacts, to describe how they are
changing in an accessible way, & to raise awareness of the
consequences of climatic warming for wildlife & for people
In addition, to assist in setting targets for the reduction of
impacts & help guide the implementation of mitigation &
adaptation measures
The indicator combines two
independent strands of work:
1. Predictions from bioclimate
envelope models
(mid-end century 2070-2099)
2. Observed trends in European birds
(1980-2005 derived from the PECBMS)
The starting point is the
EBCC’s Atlas and the
climate envelope models
fit to distribution data for
European breeding birds
Bird distributions mapped in late
1980s -- 50-km UTM squares -presence & absence of species
Based on the bioclimatic
envelope models for
each bird species, Brian
Huntley et al., have
published the first
‘Climatic Atlas’ of its
kind for any taxa
The ‘Climatic Atlas’ uses 3 simple
bioclimate variables to model European
bird distributions:
1. ‘MTCO’
Mean temperature of the coldest month
2. ‘GDD5’
Annual temperature sum above 5 degrees C
3. ‘AET/PET’
Ratio of actual to potential evapo-transpiration
The models provided a good fit to our data (area under the curve – AUC – of a receiver operating
characteristic – ROC – plot; mean AUC of the 122 species = 0.967; lowest value = 0.907).
Present
simulated range
~1961-1990
Serin Serinus serinus
Future ‘potential’
range under a
modelled climatic
change scenario:
HadCM3 B2 for
~2070-2099
We have the PECBMS population trends e.g.
European Wild Bird Indicator 2008
Population index (1980=100)
120
-14% CommonForest (28 species)
100
80
-15% All common (124 species)
60
-43% Common Farmland (33 species)
40
1980
1985
1990
1995
Year
2000
2005
European trends for 124 common bird species were
available from the PECBMS
1000
10
1
1980
Jynx torquilla
Troglodytes troglodytes
Picus canus
Prunella modularis
Picus viridis
DryocopusErithacus
martius rubecula
100
Luscinia
Dendrocopos
majormegarhynchos
Hippolais icterina
Phoenicurus
Dendrocopos
minor phoenicurus
Turdus merula Sylvia borin
1000
10
1985
Population index (1980=100)
100
Population index (1980=100)
Population index (1980=100)
1000
Turdus philomelosSylvia atricapilla
100
Phylloscopus collybita
1990
1
1980
Turdus viscivorusPhylloscopus sibilatrix
1995
Year
10
1985
2000
1990
2005
1995
2000
Phylloscopus trochilus
Regulus regulus
2005
Year
Muscicapa striata
Ficedula albicollis
Ficedula hypoleuca
1
1980
1985
1990
1995
Year
2000
2005
We developed the indicator in two steps:
First, we tested the performance of projections of change in
the extent of species’ geographical range (termed ‘CLIM’,
based upon climatic envelope models) as predictors of
observed interspecific variation in population trends of
European birds
Testing the performance of envelope models is necessary to
address concerns about their accuracy in predicting species’
responses to climatic change
We expect a positive correlation between observed
change in abundance and ‘CLIM’
Having found a robust relationship of this kind, our second
step was to construct an indicator based upon the divergence
in population trends between species expected to be
positively and negatively affected by climatic change
Step One
The ‘CLIM’ value for a species is the loge of the ratio
of the extent of the future potential range to that of
the recent simulated range
(CLIM >0 predicts range expansion, CLIM <0 predicts range contraction)
We also looked at the influence of habitat choice, migratory
behaviour & body mass (as a proxy for life history
characteristics) in predicting bird trends
Step One
To test for sensitivity of the scenario projections
we considered results from:
• 3 General Circulation Models (GCM): HadCM3, Echam4
& GFDL
• 2 Scenarios from the Special Report on Emissions
Scenario (SRES): A2 & B2
• = 6 variants termed ‘CLIMHaA2’, ‘CLIMHaB2’,
‘CLIMEcA2’, ‘CLIMEcB2’, ‘CLIMGfA2’ and ‘CLIMGfB2’
• We also calculated the average of these 6 to create an
‘ensemble forecast’, termed ‘CLIMEns’
Population trends of 108 bird species in 20 European
countries 1980 – 2005 correlated significantly with
projected trend in climate suitability from the climate
envelope models
0.1
Observed
decrease
Observed trend
Observed
increase
0
-0.1
-0.2
-0.03
-0.02
-0.01
0
0.01
0.02
CLIM value
Retrodicted range decrease
Retrodicted range increase
0.03
We found a highly significant +ve correlations between
interspecific variation in recent population trends & the CLIM
projections
Standardised regression coefficient
0.5
0.4
0.3
0.2
0.1
0
-0.1
CST
CLIMEns+
CLIMEns -
CLIMEns
CLIMGfB2
CLIMGfA2
CLIMEcB2
CLIMEcA2
CLIMHaB2
CLIMHaA2
Climatic Response Predictor
?
Lots of assumptions. One is that the bioclimate
variables have changed since 1980 in the direction
of the GCMs for the longer-term predictions
• We tested this by examining the relationship of CLIM & the
recent trend in climate suitability based upon observed
climate change 1980-2005
• We used the climate envelope models and the annual
values of the bioclimate variables to calculate probability
of occurrence in each year for each species
• We then regressed these against year for each species
and the slope of this line is what we call the ‘Climate
Suitability Trend’ (CST)
Encouragingly, we found:
1. A highly significant relationship between interspecific
variation in CLIM and CST
- So climate suitability for species is changing just
as we’d predict
2. A marginally significant relationship between observed
population trend and CST when controlling for
confounding variables
- So bird numbers are changing just as we’d predict
over this period, but the link is quite weak
Step Two
Our second step was therefore to construct an indicator
from the observed population trajectories of 122 bird
species with data available for any part of the period
1980 – 2005
We divided these species into those for which the
climatic envelope model projection indicated an
increase in potential geographical range (CLIMEns+)
and those with projected decreases in geographical
range (CLIMEns-).
Step Two
For each of the two groups of species, we calculated a multispecies population index from population indices for
individual species, with the weight of the contribution of each
species to the index being being its absolute value of
CLIMEns
Extreme CLIM values for species (+ve or –ve) have
greater influence on the line
So birds predicted to be strongly affected by climate in
our models strongly influence the direction of the index
110
(A) Weighted population trend of species predicted to gain
range in response to climatic change (30 species)
100
95
90
85
80
75
70
65
60
1980
1985
1990
1995
2000
2005
Year
110
105
Weighted population index
Multi-species
population indices
for both species
groups declined in
the early 1980s, but
from the latter part of
that decade
onwards, CLIMEns+
(30 species)
increased, whilst
CLIMEns- index (92
species) continued
to decline
Weighted population index
105
(B) Weighted population trend of species predicted to lose
range in response to climatic change (92 species)
100
95
90
85
80
75
70
65
60
1980
1985
1990
1995
Year
2000
2005
Step Two
The impact of climatic changes (both +ve and -ve) on bird
populations can then be summarised in a single indicator,
the ‘Climatic Impact Indicator’ (CII)
This is calculated in a given year as the ratio of the index for
CLIMEns+ species to that for CLIMEns- species, and has
95% confidence limits obtained using a bootstrap method
Index of climatic change impacts on bird populations
The Climatic Impact Indicator (CII), reflecting the divergence of
the indices for the two groups, declined slightly in the early 1980s,
but has shown a roughly linear increase from then onwards
160
B
140
120
100
90
80
70
Index value
Piecewise regression
60
50
1980
1985
1990
1995
2000
2005
We can present the CII in a more accessible fashion
for a wider general audience
Index of climatic impacts on bird populations
140
130
Increasing climatic impact on bird populations
120
110
100
90
80
70
60
1980
Decreasing climatic impact on bird populations
1985
1990
1995
Year
2000
2005
B
140
Note that the pattern in the
CII closely resembles that of
observed climatic change in
Europe
120
100
90
80
70
Index value
Piecewise regression
60
50
1980
1985
1990
1995
2000
2005
2
C
Standardised climatic indices
Index of climatic change impacts on bird populations
160
1
0
-1
GDD5
MTCO
MTEMP
Piecewise regression
-2
-3
1980
1985
1990
1995
Year
2000
2005
But what does the CII show?
• It shows conformity between observed population trends
& projections of how each species’ population should
respond to climatic warming
• The CII increases when population trends go in the
direction predicted by the models
• The CII decreases when population trends go in the
opposite direction predicted by the models
Index of climate change impacts on bird populations
We can also create the CII adjusting for the confounding
effects of habitat, migratory behaviour & body mass on the
trends – but it is basically unchanged
160
140
120
100
90
80
70
Adjusted index value
Unadjusted index value
60
50
1980
1985
1990
1995
Year
2000
2005
Key messages
1. Climate change is having a detectable effect on common
bird populations at a European scale, including evidence of
negative as well as positive effects
2. The number of bird species whose populations are
observed to be negatively impacted by climatic change is 3
times that of those positively affected in our sample
3. The Climatic Impact Indicator (CII) has increased strongly in
the past 20 years, coinciding with a period of rapid warming
4. Potential links between changes in bird populations and
ecosystem functioning are not well understood. It is
suggested that increasing climatic effects might alter
ecosystem functioning & resilience
The novelty of the findings:
• Shows a strong link between observed population change
and forecast change in range extent in a large species
assemblage (widespread/common European birds)
• New observation that this link is apparently equally strong for
species predicted to be negatively & positively impacted by
climatic change
• Application of these results into an index of biotic impact of
climatic change, provides first time a robust, accessible
indicator of a phenomenon of global concern
So what does this mean
for the birds?
Potentially, at least, wide-scale changes in
bird communities across Europe with:
A few winners (?)
‘Top 10’ - Increasing birds projected to increase
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Sardinian Warbler
Subalpine Warbler
Bee-eater
Cirl Bunting
Cetti’s Warbler
Hoopoe
Golden Oriole
Goldfinch
Great Reed Warbler
Collared Dove
And many losers (?)
‘Bottom 10’ - Declining birds projected to decline
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Snipe
Meadow Pipit
Brambling
Willow Tit
Lapwing
Thrush Nightingale
Wood Warbler
Nutcracker
Northern Wheatear
Lesser Spotted Woodpecker
Special thanks to the PECBMS network
Special thanks to the data providers and organisations responsible for
national data collection and analysis: Adriaan Gmelig Meyling
(Statistics Netherlands). Norbert Teufelbauer, Michael Dvorak,
Christian Vansteenwegen, Anne Weiserbs, Jean-Paul Jacob, Anny
Anselin, Karel Šťastný, Vladimír Bejček, Jiří Reif, Henning Heldbjerg,
Michael Grell, Andres Kuresoo, Frederic Jiguet, Risto Väisänen, Martin
Flade, Johannes Schwarz, Tibor Szép, Olivia Crowe, Lorenzo
Fornasari, Ainars Aunins, Ruud P. B. Foppen, Magne Husby, Przemek
Chylarecki, Geoff Hilton, Juan Carlos del Moral, Virginia Escandell,
Ramón Martí, Åke Lindström, Hans Schmid, David G. Noble, Juha
Tiainen, Romain Julliard, Ward Hagemeijer, David G. Noble, Norbert
Schäffer, Nicola Crockford, Zoltan Waliczky, David Gibbons, Simon
Wotton, Adrian Oates, Gregoire Loïs, Dominique Richard, Anne Teller,
Jeremy Greenwood, Lucie Hošková, Václav Zámečník, Lukáš Viktora,
Tomáš Telenský, & Zdeněk Vermouzek.
Gregory R.D., Willis, S.G., Jiguet, F., Voříšek, P.,
Klvaňová, A., van Strien, A., Huntley, B Collingham,
Y.C., Couvet, D. & Green, R.E. (2009). An indicator of
the impact of climatic change on European bird
populations. PLoS ONE 4(3): e4678.
doi:10.1371/journal.pone.0004678
FREELY AVAILABLE AT:
http://www.plosone.org/article/info:doi/10.1371/journal.pone.00046
78
Next steps
•
•
•
•
•
•
Update CII with new trend data
Repeat at national and regional scales
Build non-breeding ranges for migrants
Explore CII trend pattern and trends
Explore new modelling approaches and climate/data
Correlate projected range change with observed
range change
• We are looking for funding