caa a22 4500 463175417 CHVBK 20180406164824.0 cr unu---uuuuu 170326e20071201xx s 000 0 eng 10.1007/s10336-007-0176-7 doi (NATIONALLICENCE)springer-10.1007/s10336-007-0176-7 Smoothing and trend detection in waterbird monitoring data using structural time-series analysis and the Kalman filter [Elektronische Daten] [Leo Soldaat, Hans Visser, Marc van Roomen, Arco van Strien] Many wildlife-monitoring programmes have long time series of species abundance that cannot be summarized adequately by linear trend lines. To describe long time series better, generalized additive models may be used to obtain a smooth trend line through abundance data. We describe another approach to estimate a smoothed trend line through time series consisting of one observation per time point, such as year or month. This method is based on structural time-series models in combination with the Kalman filter and is computerized in the TrendSpotter software. One of its strengths is the possibility to test changes in smoothed abundances between years, taking into account serial correlation. The trend method is applied in the Dutch Waterbird Monitoring Scheme (DWMS), a monitoring scheme for migrating and overwintering waterbirds. Taking the numbers of overwintering Greater Scaup (Aythia marila) in the Netherlands as an example, we demonstrate three applications of the method: (1) trend calculation and classification for each year in the time series, (2) assessing alerts for alarming population declines and (3) testing yearly abundance against a population threshold. We discuss the situations where TrendSpotter is to be preferred over other methods. Dt. Ornithologen-Gesellschaft e.V., 2007 Kalman filter nationallicence Structural time-series analysis nationallicence Population alert nationallicence Trend analysis nationallicence Generalized additive model (GAM) nationallicence TRends and Indices for Monitoring data (TRIM) nationallicence Aythia marila nationallicence Greater scaup nationallicence Soldaat Leo Statistics Netherlands, PO Box 4000, 2270 JM, Voorburg, The Netherlands aut Visser Hans Netherlands Environmental Assessment Agency (MNP), Bilthoven, The Netherlands aut van Roomen Marc SOVON Dutch Centre for Field Ornithology, Beek-Ubbergen, The Netherlands aut van Strien Arco Statistics Netherlands, PO Box 4000, 2270 JM, Voorburg, The Netherlands aut Journal of Ornithology Springer-Verlag 148(2007-12-01), 351-357 0021-8375 148<351 2007 148 10336 https://doi.org/10.1007/s10336-007-0176-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10336-007-0176-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Soldaat Leo Statistics Netherlands, PO Box 4000, 2270 JM, Voorburg, The Netherlands aut NATIONALLICENCE 700 1- Visser Hans Netherlands Environmental Assessment Agency (MNP), Bilthoven, The Netherlands aut NATIONALLICENCE 700 1- van Roomen Marc SOVON Dutch Centre for Field Ornithology, Beek-Ubbergen, The Netherlands aut NATIONALLICENCE 700 1- van Strien Arco Statistics Netherlands, PO Box 4000, 2270 JM, Voorburg, The Netherlands aut NATIONALLICENCE 773 0- Journal of Ornithology Springer-Verlag 148(2007-12-01), 351-357 0021-8375 148<351 2007 148 10336 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer