Methods 2014

Compiled by Petr Voří¹ek, Arco Van Strien, Willy Van Strien, Jana ©korpilová, Ian Burfield and Richard D. Gregory

What is new in 2014 data update?

  1. Compared to the last year, we newly modified the presentation of species trends and we present new long-term and ten-year trends and slopes. Contrary to the former Long-term Slope, the new Long-term Slope is calculated over the period 1980-2012 but starting years of this long time period vary from 1980 to 1998 (as specified in the Species notes below the table of trends). In parallel, the new Long-term Trend is replacing the former Trend 1980 (´long-term trend´) and represents a change (in %) in an index value between the first and the last year of this long time period. The new Ten-year Slope is replacing the former Short-term Slope and is calculated over the period of last ten years, i.e. 2003-2012. Similarly, the new Ten-year Trend is replacing the former Trend 1990 (´short-term trend´) and represents a change (in %) in an index value between the first and the last year of the period of last ten years.
  2. Computation procedure as well as data quality control has not undergone any change, it has been kept consistent with last year data update.

The methods that PECBMS uses to produce species population trends and indices and wild bird indicators have been described in several scientific papers. The internationally accepted standards according to which national monitoring schemes, being the data source for PECBMS, are organized, are available in textbooks and scientific papers. Also, the PECBMS Best Practice Guide (Voří¹ek et al., 2008) contains many information on methods. But as a consequence, the information on methods is scattered. On this web page we bring together all this information to facilitate the understanding of data collection, and analysis procedures. The text in Methods proceeds step by step, from national bird monitoring schemes to European multispecies bird indicators, and ends with a chapter on quality control performed at each step.

The most important questions that have been asked about PECBMS methods and interpretation of results are answered on a separate page: Questions and Answers.

Information on the aims & structure of PECBMS, the results, the use, some history and future plans is given on the page What is PECBMS?

Production of European population trends and indices and indicators: an overview (click on for the larger picture)


1. National species indices and trends

1.1 Counting birds
Box Field methods
Box Detectability
Box Selection of sample plots
1.2 Production of national indices and trends
Box Missing values I
Box Trend interpretation and classification

2. Supranational species indices and trends

2.1. Delivery of national data to PECBMS coordination unit
Box Data checks
Box Participating countries
2.2. Combining national data into supranational outputs
Box Missing values II
2.3. Types of supranational results that PECBMS produces

3. Multispecies indicators

Box Geometric means - an example
Box Species selection and classification

4. Quality control

4.1. On the national level
4.2. At delivery to PECBMS
4.3. For supranational indices and trends
4.4. For multispecies indicators

5. References and further reading


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