Tracking animal movement is important for understanding how animals interact with their (changing) environment, and crucial for predicting and explaining how animals are affected by anthropogenic activities. The Wadden Sea is a UNESCO World Heritage Site and a region of global importance for millions of shorebirds. Due to climate change and anthropogenic activity, understanding and predicting movement and space-use in areas like the Wadden Sea is increasingly important. Monitoring and predicting animal movement, however, requires high-resolution tracking of many individuals. While high-resolution tracking has been made possible through GPS, trade-offs between tag weight and battery life limit its use to larger species. Here, we introduce WATLAS (the Wadden Sea deployment of the ATLAS tracking system) capable of monitoring the movements of hundreds of (small) birds simultaneously in the Dutch Wadden Sea. WATLAS employs an array of receiver stations that can detect and localize small, low-cost tags at fine spatial (metres) and temporal resolution (seconds). From 2017 to 2021, we tracked red knots, sanderlings, bar-tailed godwits, and common terns. We use parts of these data to give four use-cases revealing its performance and demonstrating how WATLAS can be used to study numerous aspects of animal behaviour, such as, space-use (both intra- and inter-specific), among-individual variation, and social networks across levels of organization: from individuals, to species, to populations, and even communities. After describing the WATLAS system, we first illustrate space-use of red knots across the study area and how the tidal environment affects their movement. Secondly, we show large among-individual differences in distances travelled per day, and thirdly illustrate how high-throughput WATLAS data allows calculating a proximity-based social network. Finally, we demonstrate that using WATLAS to monitor multiple species can reveal differential space use. For example, despite sanderlings and red knots roosting together, they foraged in different areas of the mudflats. The high-resolution tracking data collected by WATLAS offers many possibilities for research into the drivers of bird movement in the Wadden Sea. WATLAS could provide a tool for impact assessment, and thus aid nature conservation and management of the globally important Wadden Sea ecosystem.
Bibliographical noteFunding Information:
Many people and organisations are involved in hosting the WATLAS equipment, without whom this study would be impossible. We therefore thank Hoogheemraadschap Hollands Noorderkwartier, Koninklijke Nederlandse Redding Maatschappij, Staatsbosbeheer, Marine Eco Analytics, Koninklijke Luchtmacht, Het Posthuys (Vlieland), Natuurmonumenten, Wetterskip Fryslan, Afsluitdijk Wadden Center, Vermilion, Rijkswaterstaat, Carl Zuhorn, Lenze Hofstee and Lydia de Loos. We thank Natuurmonumenten for access to Griend and using their facilities. Also, we thank Hein de Vries, Klaas-Jan Daalder, Hendrik-Jan Lokhorst, Bram Fey, Wim-Jan Boon from the RV Navicula and RV Stern, as well as the many other NIOZ staff and volunteers that facilitated this work. We would particularly like to thank Anita Koolhaas, Hinke and Cornelis Dekinga for their help with building the receiver stations. We thank Jeras de Jonge, Martin Laan, Sander Asjes, and Aris van der Vis for their technical help, and Benjamin Gnep for his beautiful photos and persistently replacing broken LNA’s. Thanks to Marten Tacoma for visualizing the tracking data in real time on www.nioz.nl/watlas and Ingrid de Raad for help posting WATLAS-related news. We also thank the Minerva Foundation and the Minerva Center for Movement Ecology for supporting the development and maintenance of all ATLAS systems, and for Yotam Orchan and Yoav Bartan for their most valuable technical assistance. Finally, we thank Theunis Piersma, three anonymous referees and the associate editor for providing valuable comments and suggestions for improvements on an earlier version of this manuscript.
This work was partly funded by the Dutch Research Council grand VI.Veni.192.051 awarded to AIB, and Grants from the Israel Science Foundation to RN and ST (ISF Grants 965/15 and 1919/19) for supporting the development and maintenance of all ATLAS systems.
© 2022, The Author(s).
- Animal tracking
- High-throughput movement ecology
- Space use
- Wadden Sea UNESCO World Heritage Site