Unstructured citizen science data fail to detect long‐term population declines of common birds in Denmark

• DOI: 10.1111/ddi.12463
• Publication Date: 2016-07-11T02:16:55Z
• Authors: Johannes Kamp; Steffen Oppel; Henning Heldbjerg; Timme Nyegaard; Paul F. Donald
• Keywords: Citizen Science; Unstructured data

Abstract Aim Long‐term monitoring of biodiversity is necessary to identify population declines and develop conservation management. Because long‐term labour‐intensive, resources implement robust programmes are lacking in many countries. The increasing availability citizen science data online public databases can potentially fill gaps structured programmes, but only if trends estimated from unstructured match those programmes. We therefore aimed assess the correlation between data. Location Denmark. Methods compared for 103 bird species over 28 years a programme whether two sources were correlated. Results Trends generally positively correlated, less than half identified recovered mismatch persisted when we reduced count occurrence mimic information content filtered reduce number incomplete lists reported. Mismatching especially prevalent most common species. Worryingly, more showing significant showed positive Main conclusions caution that cannot replace because former sensitive changes. Thus, may not fulfil one critical functions namely act as an early warning system detects declines.