Noticia y artículo (adjunto pdf)
European conservation works: Science paper reveals
successes of the EU Birds Directive
Today, the renowned journal Science publishes a
BirdLife International analysis showing that the European Union’s Birds
Directive has made a significant difference in protecting many of the
continent’s most threatened birds from further decline.
Conservation success: Eurasian Spoonbill
The groundbreaking paper shows that the Birds Directive has
clearly helped those species considered to be most at risk, partly
through the designation of Special Protection Areas (SPAs). The Birds
Directive was adopted in 1979 and is now binding law for all EU
countries, it requires special conservation measures for a number of
Importantly, today’s research, taking into account the fifteen
Member States for which sufficient data were available, showed that the
populations of threatened birds not only fared better, on average, than
other bird species in the European Union, but also that the same
species perform better within the EU than in European countries
Dr Paul Donald, the paper’s senior author from the RSPB
(BirdLife in the UK) said: “For over 25 years, the Birds Directive has
helped provide proper protection for those bird species facing the
greatest threats. Today we can reveal that this protection has
"Europe has a world class conservation law and
there is no excuse any more for delayed action."
EU Policy Manager at BirdLife's European Division
Eurasian Spoonbill Platalea leucorodia, White-tailed
Eagle Haliaeetus albicilla and Spanish Imperial Eagle Aquila
prominent examples of this success: without the Birds Directive and the
efforts of governments and conservationists to implement it on the
ground, these birds would now face a much bleaker future.
BirdLife hopes this evidence will now boost efforts of
governments to comply with the Birds Directive, especially in the new
Member States of the EU.
In June, the European Commission started legal action against
many Member States after failing to designate enough protected areas
for birds. In recent months, Poland has also faced Europe-wide
criticism for the construction of an expressway through the pristine
Rospuda Valley, a very important site protected under the Birds
Konstantin Kreiser, EU Policy Manager at BirdLife
International in Brussels, said: “Europe has a world class conservation
law and there is no excuse any more for delayed action.” BirdLife warns
that insufficient designation and protection of sites, lack of funding
for site management and unsustainable agriculture all could reverse the
successes of the Birds Directive, perpetuating dramatic declines in
Science 10 August 2007:
Vol. 317. no. 5839, pp. 810 - 813
International Conservation Policy Delivers Benefits for Birds in
Paul F. Donald,1*
Fiona J. Sanderson,1
Ian J. Burfield,2
Stijn M. Bierman,3
Richard D. Gregory,1
Conservation of the planet's biodiversity will depend on
international policy intervention, yet evidence-based
assessment of the success of such intervention is lacking.
Poor understanding of the effectiveness of international
policy instruments exposes them to criticism or abandonment
and reduces opportunities to improve them. Comparative analyses
of population trends provide strong evidence for a positive
impact of one such instrument, the European Union's Birds
Directive, and we identify positive associations between the
rate of provision of certain conservation measures through the
directive and the response of bird populations. The results suggest
that supranational conservation policy can bring measurable conservation
benefits, although future assessments will require the
setting of quantitative objectives and an increase in the availability
of data from monitoring schemes.
1 Royal Society for the Protection of Birds, The Lodge,
Sandy, Bedfordshire SG19 2DL, UK.
2 BirdLife International, Wellbrook Court, Girton Road,
Cambridge CB3 0NA, UK.
3 Biomathematics and Statistics Scotland, University of
Edinburgh, The King's Buildings, Edinburgh EH9 3JZ, UK.
* To whom correspondence should be addressed. E-mail: paul.sonald@...
Because global threats to biodiversity are largely anthropogenic,
already considerable in scale, and accelerating rapidly (1),
their solutions will depend largely on international policy intervention.
This was recognized in the formulation of international agreements
such as the Convention on Biological Diversity (CBD); at
least 20 regional or global conservation agreements currently exist,
absorbing a high proportion of global conservation resources (2).
Evaluation of the impact of international conservation policy
intervention lags far behind that of most other policy fields
largely because of a paucity of data on the response of the
species to which intervention is targeted (4,
This leads to a poor understanding of the cost
effectiveness of the relevant policy instruments (6),
reducing opportunities to improve them (7)
and exposing them to criticism from both within and outside
the conservation lobby (8).
Although properly implemented conservation legislation can
bring measurable benefits to wildlife (9–11),
evaluation has hitherto had its basis either in an
assessment of the provision of conservation resources, rather than
the population responses of the target species to such provision,
or in the responses of a small, possibly unrepresentative proportion
of the species or countries to which such legislation was
targeted. We assessed the impact of an international bird conservation
policy that covers all member states of the European Union
(EU) by using data on all the species and countries to which
the agreement applies. We aimed to provide an independent assessment
of the extent to which a major international policy instrument
has resulted in the delivery of measurable conservation outcomes.
Biodiversity conservation legislation in the EU is founded primarily
on two directives, Council Directive 79/409/EEC of 2 April 1979
on the conservation of wild birds (the Birds Directive) and Council
Directive 92/43/EEC of 21 May 1992 on the conservation of
natural habitats and of wild fauna and flora (the Habitats Directive).
The Birds Directive set out to establish a framework and
objectives for the conservation of all birds throughout the
EU, although the precise legal mechanisms for achieving this
aim were left to the discretion of individual member states. Central
to the directive was a list (Annex I) of species considered to
be particularly vulnerable or rare or to require special conservation
Member states are bound by the directive to improve the
conservation status of these species by protecting or
enhancing their habitats, for example, through the designation of
special protection areas (SPAs) (12).
Furthermore, a number of general measures to protect
populations of all bird species was also agreed upon. No
quantitative targets were set in the directive, so we
developed five expectations that should be met for us to
conclude that the directive has had a detectable positive
impact. (i) We expected to detect an improvement in the
population trajectory of species listed on Annex I after the
implementation of the directive, relative to that of non–Annex I
species, within the original 15 member states of the EU (EU15). (ii)
We expected any improvement in the population trajectory of
Annex I species relative to non–Annex I species in the EU15
to be significantly greater than that recorded in parts of
Europe to which the directive does not apply. (iii) We expected trends
of Annex I and non–Annex I species to be more positive within
the EU15 than outside it. (iv) We expected any positive impacts
of Annex I listing to be most apparent in species that have
been listed for longest. (v) We expected to detect a positive association
across participating countries between the extent to which
the directive's conservation initiatives were deployed and
trends in bird populations. Our analytical approach has its
basis in the statistical testing of these five expectations.
Major inventories on the status and population trends of all of
Europe's breeding birds, collected at a country level and covering
the periods 1970–1990 and 1990–2000 (13,
provided the opportunity to evaluate the impact of the Birds
Directive. In each period, population trends of each species in
each European country were allocated a single population trend
score; these have already been published (13,
and formed the data we modeled to test the expectations
described above. The availability of data from two time
periods, and from within and outside the EU, permitted an
analysis with serendipitous characteristics of a highly
replicated before-after-control-impact (BACI) approach (15).
This permitted comparison of trends before and after 1990,
between Annex I and non–Annex I species within the EU, and
between Annex I species in the EU and the same group of
species outside the EU (16).
The use of a semi-experimental design based on both
horizontal and longitudinal comparisons and the testing of
multiple expectations maximized the likelihood that the
observed patterns were causally related to variables identified
by the models as having significant explanatory power.
Because the aim of the analysis was to examine the impact of Annex
I listing by using trends over the period 1990–2000, we
limited comparisons to data from the EU15, all but three of
which joined the EU before the start of the 1990–2000 census
For the same reason, we restricted our list of Annex I
species to those added to the Annex before 1993 (12).
Because trends were recorded in bands of unequal width (ordered
from increasingly negative to increasingly positive population
trends), we treated the response variable as ordinal and used
the proportional odds model to assess differences between groups
of species in the cumulative probabilities of being in higher
ordered trend bands (16).
After controlling for known variation within the database
in trends between species using different habitats (18),
between migrants and nonmigrants (19),
and for the non-independence of trends within countries and
species, we detected a highly significant effect of Annex I
1). In the EU15, Annex I species were significantly
more likely to be assigned to a lower population trend
class than non–Annex I species in 1970–1990. However, this
pattern was reversed in 1990–2000, when Annex I species
were significantly more likely to be recorded in a higher
population trend band than non–Annex I species (Fig.
1A), thus meeting our first expectation. Outside the
EU15, although trends of Annex I species improved
significantly compared to those of non–Annex I species,
they were no more likely to have more positive trends than
non–Annex I species in 1990–2000 (Fig.
1B). The difference in trend between Annex I and
non–Annex I species did not differ between the EU15 and
non-EU15 countries in 1970–1990 [difference in log(odds
ratios) = 0.17 ± 0.22 SE] but was significantly greater in
the EU15 than in non-EU15 countries in 1990–2000
[difference in log(odds ratios) = 0.52 ± 0.18 SE]. Thus,
our second expectation was met.
||Fig. 1. Odds ratios
(±95% confidence limits) from proportional odds models (16).
Each bar indicates the ratio of two groups of species in their
cumulative odds of being in a more positive trend band in one of two
time periods, with significant deviations from 1 indicated (*P
<0.05, **P <0.01, ***P < 0.001). The odds ratios indicate how
many times higher the odds were of populations of Annex I species
having more positive trends than populations of non–Annex I species in
the EU15 (A) and outside the EU15 (B) in each time
period. Significant positive deviation from an odds ratio of 1
indicates a significantly higher probability that Annex I species had
more positive trends than non–Annex I species; odds ratios that are
significantly smaller than 1 indicate the reverse. The cumulative odds
of species in the EU15 having a more positive population trend than
those in non-EU15 countries are shown for Annex I species (C),
non–Annex I species (D), and all species combined (E).
All models controlled for the known effects on trend of each species'
habitat and migration strategy and controlled for the non-independence
of trends within species across countries.
Larger Version of this Image (17K GIF file)]
There was no significant difference in trends of Annex I species
within and outside the EU15 in 1970–1990. However, by 1990–2000,
Annex I species in the EU15 were significantly more likely
to be recorded in a higher trend band than the same group
of species outside the EU15 (Fig.
1C), a pattern that was not apparent in non–Annex I
1D) or across all species combined (Fig.
1E). Our third expectation was therefore partly met.
Between 1990 and 2000, species listed on Annex I of the Birds Directive
fared significantly better on average than non–Annex I
species within the EU15, a pattern not apparent in the same groups
of species outside the EU15. This difference withstood controls
for phylogenetic non-independence (16)
and was due almost entirely to trends of species that had
been listed on Annex I for longest (fig. S1), supporting
both our fourth expectation and a previous estimate (9)
that the lag between policy intervention and a detectable
population-level response exceeds 10 years. Because the
effects of both habitat and migration strategy were controlled
in the analyses, this difference could not be ascribed to
Annex I species being disproportionately represented in habitat or
migration classes that fared better than average. Nor could the
difference be accounted for by the deliberate or fortuitous allocation
to Annex I of species that were already increasing, because
most of these species were listed well before 1990, when
their trends were significantly more negative than those of
non–Annex I species (Fig.
1A). Lastly, the difference in trends between Annex I
and non–Annex I species in the EU could not be explained by
a general global increase in Annex I species, for example
in response to climate change, because outside the EU15
Annex I trends were no different from those of non–Annex I
Evidence for a causal link between policy intervention and species
response (our fifth expectation) was found in the positive
association across EU15 countries between mean species
trend and the proportion of land designated as SPAs (Fig.
2). This pattern was apparent for all species combined,
and for Annex I and non–Annex I species separately, and was
significantly stronger for Annex I than for non–Annex I
species. Parameters of proportional odds models suggested
that, for every additional 1% of a country's land area
designated as SPAs, the odds of a species being in more-positive
population trend classes increased by around 4% across all
species and for non–Annex I species and by around 7% for
Annex I species (16).
The significantly stronger response of Annex I species to
the provision of SPAs is consistent with a causal link
between the delivery of conservation measures through the
directive and the response of the target species because
SPA designation and management are targeted largely toward
Annex I species.
||Fig. 2. Plot of
country estimates of log (odds ratios) against
the percentage of land area designated as SPAs in the EU15 member
states for Annex I and non–Annex I species combined (means ± SE and
black regression line; slope = 0.042). The odds ratios indicate the
extent to which species are more or less likely to appear in
more-positive trend classes than species in the reference country (UK),
which has a value of zero and no SE. In order to graphically represent
this relationship, country effects of odds ratios were extracted from a
proportional odds model of trend class, with migration strategy and
breeding habitat also fitted as fixed effects and species fitted as a
random effect. The regression coefficient differed significantly from
zero (P < 0.02) and was estimated by fitting percentage of SPA cover
directly as a covariate in a proportional odds model and including a
random country effect (16).
A similarly significant positive association was apparent for Annex I
(regression line only shown in blue, slope = 0.068) and non–Annex I
(regression line only shown in red, slope = 0.036) species separately.
A significant (P < 0.01) interaction term indicated that the slopes
for Annex I and non–Annex I species differed.
Larger Version of this Image (16K GIF file)]
Therefore, four of our five expectations of a positive impact of
the Birds Directive were fully met, and the remaining one was
partly met (populations of Annex I species, although not of
non–Annex I species, had more positive trends in the EU15
than outside it). Furthermore, although trends of non–Annex I
species did not differ between the EU15 and other countries, there
was evidence that trends of these species were more positive within
the EU15 in countries with higher deployment of SPAs. The
data are therefore consistent with the hypothesis that the Birds
Directive has brought demonstrable benefits to bird populations in
the EU and that international policy intervention can be effective
in addressing conservation issues over large geographical areas.
Our results support previous assertions (4,
that relatively simple yet robust population monitoring can
play an important role in assessing the success of
supragovernmental conservation policies, as it already has
in demonstrating the environmentally damaging effects of
international policy in other sectors (21).
Much biodiversity monitoring is undertaken by volunteers (22),
making it inexpensive relative to the costs of developing and
implementing international policy. If such policies were to provide
support for monitoring, for example by contributing to a
global monitoring network (23),
their success could be evaluated. Furthermore, setting
targets that are both quantitative and measurable would
increase the resolution of subsequent assessments. Precise
goals and specific measures for monitoring policy effectiveness should
be designed and tested at the time that the policy is implemented.
Otherwise, quantitative assessments of policy intervention will
continue to depend on post hoc, serendipitous analyses of
the type presented here. Until policy and monitoring become more
integrated, the success of international conservation policies in
protecting the planet's biodiversity or in achieving goals such
as the CBD's 2010 target to reduce the rate of biodiversity loss
will be difficult or impossible to quantify. The prognosis for
biodiversity is grim because this lack of feedback can only serve
to weaken international policy intervention at a time of
References and Notes
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measures it introduced, and a list of species classified in the
analyses as Annex I species are given in the Supporting Online Material
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We thank R. B. Bradbury, D. J. Cartwright, D. Elston, A. Gammell, D. W.
Gibbons, R. E. Green, D. J. Pain, W. J. Sutherland, and two anonymous
referees for help and comments and the many observers across Europe who
collected the data. The 1970–1990 data set was compiled by G. Tucker
and M. Heath, in association with the European Bird Census Council.
S.M.B. gratefully acknowledges funding from the EU, contract no.
Supporting Online Material
Materials and Methods
Received for publication 4 June 2007. Accepted for publication 18