DOI: 10.5061/dryad.j8cm402
title: Data from: Agricultural pastures challenge the attractiveness of natural saltmarsh for a migratory goose

description: 1. Broad-scale land conversions and fertilizer use have dramatically
 altered the available staging area for herbivorous long-distance migrants.
 Instead of natural land, these birds rely increasingly on pastures for
 migratory fuelling and stopover, often conflicting with farming practices.
 To be able to predict and manage birds’ future habitat use, the relative
 advantages and disadvantages of natural (e.g. saltmarsh, intertidal)
 versus anthropogenic staging sites for foraging need to be understood. 2.
 We compared the migratory staging of brent geese on saltmarsh and pasture
 sites in spring. Food quality (nitrogen and fibre content), intra-specific
 antagonistic behaviour, and body weight were quantified at nearby sites in
 simultaneous seasons. Individuals were tracked with high-resolution GPS
 and accelerometers to compare timing of migration and time-budgets during
 fuelling. 3. On pastures, birds rested more and experienced higher
 ingestion rates, similar or superior food quality and reduced antagonistic
 interactions than on saltmarsh. 4. Brent geese using fertilized grasslands
 advanced their fuelling and migration schedules compared to those using
 saltmarsh. Pasture birds reached heavy weights earlier, departed sooner,
 and arrived in the Arctic earlier. 5. Intertidal mudflats were frequently
 visited by saltmarsh birds during the day, and available food there
 (algae, some seagrass) was of higher quality than terrestrial resources.
 Availability of intertidal resources was an important factor balancing the
 otherwise more favourable conditions on pastures relative to saltmarsh. 6.
 Policy implications: Disadvantages of longer foraging effort, more
 antagonistic interactions and delayed fuelling schedules on traditional
 saltmarshes may cause a trend of geese exchanging this traditional niche
 in favour of pastures, especially in a warming climate that requires
 advancement of migratory schedules. However, the high quality of
 intertidal forage allows it to complement terrestrial foraging,
 potentially removing the incentive for habitat switches to pastures. The
 relatively high quality of green algae and seagrass, and birds’ remarkable
 preference for these resources when available, provides a key for managers
 to create landscapes that can sustain this specialist’s intertidal
 lifestyle. To keep natural habitats attractive to staging geese with the
 purpose to prevent conflicts with farming practices, management actions
 should focus on conservation and restoration of saltmarsh and especially
 intertidal habitat.
description: DOI:
 https://doi.org/10.5061/dryad.6b55m22Observational and plant
 sampling data for the pasture site (Terschelling island, the Netherlands)
 can be found in Dyrad associated to an earlier publication by the authors:
 Data from: Body reserves persist as fitness correlate in a long-distance
 migrant released from food constraints. Dokter AM, Fokkema W, Bekker SK,
 Bouten W, Ebbinge BS, Müskens GJDM, Olff H, van der Jeugd HP, Nolet BA.
 Date Published: February 15, 2018 DOI:
 https://doi.org/10.5061/dryad.6b55m22Field observations of
 defecations and antagonistic interactionsField observations of
 defecations and antagonistic interactions of dark-bellied brent geese on
 the saltmarsh of Schiermonnikoog islandbehavioural_observations_schiermonnikoog.csvBiometry of dark-bellied brent geeseBiometry of dark-bellied brent geese captured on Terschelling island and Schiermonnikoog island in May 2012, as deposited in the geese.org database (accessed 24 Feb 2016).biometrics_brent_geese.csvGPS and accelerometer data for individually tracked brent geeseGPS and accelerometer tracking data of individual dark-bellied Brent geese during spring migration in 2012 and 2013, for birds departing from a pasture site (Terschelling island) and a saltmarsh site (Schiermonnikoog island).brent_gps_spring_migration.csvGPS, accelerometer and environmental data for individually tracked brent geeseGPS and accelerometer tracking data of individual dark-bellied Brent geese staging on a pasture site (Terschelling island) or a saltmarsh site (Schiermonnikoog), linked to metadata on bathymetry and tidal information.brent_gps_staging.csvweight of brent goose excretaDry weights of brent goose excreta on a saltmarshdropping_weights.csvsampling and chemical analysis of saltmarsh vegetation on Schiermonnikoog islandSampling and chemical analysis of saltmarsh vegetation on Schiermonnikoog island. For details on sampling scheme and methods see Fokkema, Wimke, Wendy Boer, Henk P. Jeugd, Adriaan Dokter, Bart A. Nolet, Luit J. Kok, J. Theo M. Elzenga, and Han Olff. "The nature of plant adaptations to salinity stress has trophic consequences." Oikos 125, no. 6 (2016): 804-811.plant_analysis.csv