- In the entire AEWA region, estimates are now available
for 98% of the 522 waterbird populations covered by the
Agreement. This is satisfactory, but the quality of many
of the estimates remains low. Population trend estimates
(whether decreasing, stable or increasing) are available
for 71% of these populations.
- The quantity and quality of waterbird population estimates
and trends in 2008 was considerably higher in Europe,
and particularly in northern and western Europe, than
in the rest of the AEWA region.
- Overall the trend status of waterbirds in the Agreement
area worsened between 1999 and 2006. The state of knowledge
of waterbird trends improved considerably, however, and
the number of populations for which there is no estimated
population trend decreased from 41% in 1999 to 29% in
2008. The result of this is that the proportion of known
populations that was estimated to be increasing declined
from 25% in 1999 to 21% in 2008, the proportion estimated
to be stable increased from 33% to 37%, and the proportion
estimated to be decreasing stayed at about the same level,
decreasing from 42 to 41%.
- A total of 92 populations that showed a decreasing
trend in both 1999 and 2008 are still considered to be
decreasing. By comparison, only 47 populations that were
increasing in 1999 were still considered to be increasing
- Improvements in the quality of IWC data allowed the
first comprehensive trend analysis of IWC data from the
East Mediterranean/Black Sea region and revealed that
many more populations in this region are in decline than
in other parts of the Europe.
Priority Geographic areas
- The quality of population estimates is high for non-breeding
waterbirds in northern western and central Europe. In
most other regions, there is a need to improve the quality
of estimates, and this need is greatest in the Asian and
sub-Saharan African portions of the AEWA region.
- In the AEWA region as a whole, of populations covered
by the Agreement with known trends, nearly twice as many
show decreasing trends (41%) as increasing trends (21%).
In the part of the Agreement Area in Asia, the situation
is much worse: only 11% of populations are known to be
increasing, but five times as many, fully 55% of populations
are known to be decreasing. 42% of population trends in
Asia remain unknown, however, and the need to improve
knowledge of population trends is greatest in this part
of the AEWA region, where the proportion of decreasing
populations is also the highest.
- Altogether, 30 of the 34 AEWA Globally Threatened or
Near Threatened species are found in Africa, 17 in the
part of the Agreement Area in Asia and only 14 in Europe.
Africa holds the highest proportion of populations recognised
as being Globally Threatened – 11.5% of all AEWA
populations occurring there are Globally Threatened or
Status of different waterbird groups
- A Red List Index (RLI) prepared by BirdLife International
shows that, overall, AEWA species are less threatened
than all birds (i.e. RLI values are greater), but between
1988 and 2008 their status has deteriorated faster (i.e.
the RLI slope is steeper).
- The AEWA region holds 19 species which are Globally
Threatened according to IUCN Criteria, and a further 15
which are Near Threatened. The four most endangered species
covered by the Agreement, appearing in the Critically
Endangered category, are Northern Bald Ibis, Siberian
Crane, Sociable Lapwing and Slender-billed Curlew. There
are five species in the Endangered category: Bank Cormorant,
Madagascar Pond Heron, Red-breasted Goose, White-headed
Duck and White-winged Flufftail. The nine most endangered
species in AEWA thus each belong to a different family.
- Families with a high proportion (100% to 35%) of unknown
population trends are, in descending order, as follows:
thick-knees, divers, plovers, crakes & rails, coursers
& pratincoles, gulls & terns, herons & egrets.
- Families with a high proportion of their populations
(50% or more) showing decreasing trends are, in descending
order, as follows: penguins, boobies, shoebill, skimmers,
oystercatchers, coursers & pratincoles, crakes &
rails, cranes, grebes, plovers, and divers.
- Families in both categories (i.e. having a high proportion
of populations with unknown trends, and a high proportion
of those with known trends in decline) are perhaps most
in need of baseline information: divers, plovers, crakes
& rails, and coursers & pratincoles.
Causes of population changes
- Our ability to describe the distribution, numbers and
population trends of waterbirds is improving steadily,
but our ability to explain them remains limited. This
report is largely descriptive and in future it may be
possible to include information on the causes of changing
population status and trends.
Priorities for further
The high number of populations whose trends were still
unknown or decreasing in 2006, and the relatively low numbers
that were stable or increasing give considerable cause for
concern. Preparation of this report has identified or confirmed
a number of priorities that should be addressed by AEWA.
1. Enhance the quality and
quantity of monitoring and surveillance of waterbirds
The largest single source of data on waterbird numbers,
distribution and trends for AEWA is the International Waterbird
Census (IWC). In order to produce more data of higher quality
that better serves the needs of AEWA, the following improvements
in IWC are needed:
Additional monitoring is also needed to obtain an understanding
of the biological processes that underly population changes
in each species. This should involve:
- Expansion of IWC into a representative set of sites
in all countries in the AEWA region.
- Counts at times of year other than January, to allow
monitoring of waterbirds during migration and breeding
- Special surveys of species not well monitored by IWC
methodology, especially cryptric species, nocturnal species,
colonially nesting species and species with dispersed
Better understanding of the migrations and movements of
waterbirds is also needed, requiring:
- Internationally coordinated monitoring of productivity
of a wide selection of species. A relatively high proportion
of waterbird populations have centres of breeding distribution
in Arctic and Boreal Russia, and the inclusion of Russia
in AEWA processes should remain a high priority.
- Internationally coordinated monitoring of mortality
of as many species as possible, including hunting mortality,
and making use of data derived from bird ringing.
- Full analyses of existing ringing data and their
use in preparation of flyway atlases for all waterbird
species in the AEWA region; as well as enhancement of
bird ringing programmes wherever necessary.
- Satellite telemetry studies of selected species.
2. Improve knowledge of the causes
of changes in waterbird status and trends
An improved understanding of causes of change in waterbird
numbers will be gained by:
- Systematic, comprehensive literature reviews.
- Improved analyses of data derived from waterbird
counting and ringing. This will include the use of GIS
to allow spatial analysis of bird count and movement data
in relation to land use, climate and many other relevant
- Work on habitat use by waterbirds. The inclusion
of habitat data in a GIS directory of count sites will
allow better understanding of ecological processes influencing
waterbird demography. Habitat types that are currently
inadequately covered by waterbird survey work include
offshore marine areas, wetlands in arid regions, grasslands
and steppes, and African swamps.
- Increasing numbers of waterbirds can indicate
underlying environmental problems as well as decreasing
ones, and research into the species and habitats involved
should be a priority.
Implementation of these priorities will require large-scale
capacity development in most countries in the AEWA region.