This core indicator evaluates the status of the bird species breeding in the Baltic Sea area by assessing fluctuations in abundance. As a rule, good status is achieved when the abundance of 75% of the considered species making up a species group do not decline by more than 30% (20% in species laying only one egg per year) compared to a baseline during the reference period 1991-2000.
Key message figure 1. Status of the indicator 'abundance of waterbirds in the breeding season'. The current assessment is presented for coastal areas. The assessment is for the entire Baltic Sea – including all species currently assessed (top left, Scale 1 HELCOM assessment units, defined in the HELCOM Monitoring and Assessment Strategy Attachment 4) and for seven sudivisions of the Baltic Sea (see Assessment unit figure 1). Results for the species groups are based on the trends of individual species: surface feeders (top middle), pelagic feeders (top right), benthic feeders (bottom left), wading feeders (bottom middle) and grazing feeders (bottom right). NOTE: due to the size of figures within the composite image details in some coastal areas are better visualised via the HELCOM Map and Data Service (MADS). Click here to access interactive maps at the HELCOM Map and Data Service: Abundance of waterbirds in the breeding season, surface feeders, pelagic feeders, benthic feeders, wading feeders, grazing feeders.
The indicator performs status evaluations by aggregating annual single species index values for all waterbird species and on the basis of aggregated indices for five species groups (wading feeders, surface feeders, pelagic feeders, benthic feeders, grazing feeders).
The assessment is only carried out for coastal areas (not offshore). Since harmonized offshore monitoring could not be conducted for this assessment period and several species show strong declines in the whole offshore area (Skov et al. 2011), an overall assessment of birds is not possible and the data and results are based only on land based observations.
On the scale of the entire Baltic Sea the evaluation for the assessment period 2011-2016 showed a good status for all waterbird species when considered together, but diverging results for the species groups. While surface feeders, pelagic feeders, benthic feeders and grazing feeders achieved the threshold value indicating a good status, wading feeders failed to achieve the threshold value and do not indicate good status.
On a finer spatial scale, the status for breeding waterbirds was assessed in seven subdivisions of the Baltic Sea (see Assessment units figure 1). The results define a different perspective and diverging evaluations bwteen the spatial subdivisions.
The confidence of the indicator evaluation is estimated to be intermediate.
The core indicator is applicable in the waters of all the countries bordering the Baltic Sea. However, the current evaluation does not include data from Russia and Lithuania.
Waterbirds are an integral part of the Baltic marine ecosystem. They are important predators, often at a high level in the marine food web. The indicator follows temporal change in the abundance of key waterbird species, which responds to numerous pressures, many of them owing to human activities. Thus, the indicator gives a more general view on the state of marine birds in the Baltic Sea and reflects the cumulative impact of pressures.
D1C2 The population abundance of the species is not adversely affected due to anthropogenic pressures, such that its long-term viability is ensured.
D1C3 The population demographic characteristics of the species are indicative of a healthy population which is not adversely affected due to anthropogenic pressures.
D1C4 The species distributional rangeand where relevant, pattern is in line with prevailing physiographic, geographic and climatic conditions.
D4C1 The diversity of the trophic guild is not adversely affected due to anthropogenic pressures.D4C2 The balance of total abundance between the trophic guilds is not adversely affected due to anthropogenic pressuresD4C4 Productivity of the trophic guild is not adversely affected due to anthropogenic pressures.
HELCOM (2018). Abundance of waterbirds in the breeding season. HELCOM core indicator report. Online. [Date Viewed], [Web link].
Abundance of waterbirds in the breeding season HELCOM core indicator 2018 (pdf)