Assessing the effects of human activities on the foraging opportunities of migratory shorebirds in Austral high-latitude bays

Navedo, Juan G.; Verdugo, Claudio; Rodríguez-Jorquera, Ignacio A.; Abad‐Gómez, José M.; Suazo, Cristián G.; Castañeda, Luis E.; Araya, Valeria; Ruiz, Jorge; Gutiérrez, Jorge S.

doi:10.1371/journal.pone.0212441

Cited by 31 publications

(45 citation statements)

References 69 publications

(83 reference statements)

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“…For our study, godwit density also positively influenced flock body condition, suggesting that high godwit densities indicated high patch quality (Swift, 2018). Godwit density and time spent foraging were both reduced in a highly disturbed site on Chiloé (see also Navedo et al, 2019). Mudflat quality was, in turn, positively associated with return rates to the breeding grounds and reproductive success.…”

Section: Habitat Quality Body Condition and Reversible State Effectsmentioning

confidence: 86%

“…This means that efforts to actively mitigate the circumstances currently affecting environmental conditions on Chiloé Island could successfully avert potential future godwit population declines. For instance, efforts to minimize the number of algae harvesters (and their accompanying animals) in the intertidal zone could greatly alter the experienced quality of bays across the island (Navedo et al, 2019;Swift, 2018). Given that our results indicate a 77% difference in the breeding performance scores between godwits that spent the nonbreeding season in high-and low-quality habitats, the response of godwits to such changes could be rapid.…”

Section: Reversible State Effects and Godwit Population Dynamicsmentioning

confidence: 99%

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Seasonal survival and reversible state effects in a long‐distance migratory shorebird

Swift

Rodewald

Johnson

et al. 2020

Journal of Animal Ecology

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Events during one stage of the annual cycle can reversibly affect an individual's condition and performance not only within that stage, but also in subsequent stages (i.e. reversible state effects). Despite strong conceptual links, however, few studies have been able to empirically link individual‐level reversible state effects with larger‐scale demographic processes. We studied both survival and potential reversible state effects in a long‐distance migratory shorebird, the Hudsonian Godwit Limosa haemastica. Specifically, we estimated period‐specific survival probabilities across the annual cycle and examined the extent to which an individual's body condition, foraging success and habitat quality during the nonbreeding season affected its subsequent survival and reproductive performance. Godwit survival rates were high throughout the annual cycle, but lowest during the breeding season, only slightly higher during southbound migration and highest during the stationary nonbreeding season. Our results indicate that overwintering godwits foraging in high‐quality habitats had comparably better nutritional status and pre‐migratory body condition, which in turn improved their return rates and the likelihood that their nests and chicks survived during the subsequent breeding season. Reversible state effects thus appeared to link events between nonbreeding and breeding seasons via an individual's condition, in turn affecting their survival and subsequent reproductive performance. Our study thus provides one of the few empirical demonstrations of theoretical predictions that reversible state effects have the potential to influence population dynamics.

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Section: Habitat Quality Body Condition and Reversible State Effectsmentioning

confidence: 86%

Section: Reversible State Effects and Godwit Population Dynamicsmentioning

confidence: 99%

Seasonal survival and reversible state effects in a long‐distance migratory shorebird

Swift

Rodewald

Johnson

et al. 2020

Journal of Animal Ecology

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“…The study was carried out on a population of Hudsonian godwits (Fig. 1A) that spend the boreal winter on Chiloé Island, southern Chile 26 . Godwits depart from Chiloé Island in March and fly non-stop to central United States, with most individuals stopping only once before again flying non-stop to their breeding grounds in Alaska 24 .…”

Section: Methodsmentioning

confidence: 99%

Oxidative status and metabolic profile in a long-lived bird preparing for extreme endurance migration

Gutiérrez

Sabat

Castañeda

et al. 2019

Sci Rep

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The high metabolic activity associated with endurance flights and intense fuelling of migrant birds may produce large quantities of reactive oxygen species, which cause oxidative damage. Yet it remains unknown how long-lived birds prepare for oxidative challenges prior to extreme flights. We combined blood measurements of oxidative status and enzyme and fat metabolism in Hudsonian godwits (Limosa haemastica, a long-lived shorebird) before they embarked on non-stop flights longer than 10,000 km during their northbound migrations. We found that godwits increased total antioxidant capacity (TAC) and reduced oxidative damage (TBARS) as the pre-migratory season progressed, despite higher basal metabolic rates before departure. Elevations in plasma β-hydroxybutyrate and uric acid suggest that lipid and protein breakdown supports energetic requirements prior to migration. Significant associations between blood mitochondrial cytochrome-c oxidase and plasma TAC (negative) and TBARS (positive) during winter indicate that greater enzyme activity can result in greater oxidative damage and antioxidant responses. However enzyme activity remained unchanged between winter and premigratory stages, so birds may be unable to adjust metabolic enzyme activity in anticipation of future demands. These results indicate that godwits enhance their oxidative status during migratory preparation, which might represent an adaptation to diminish the physiological costs of long-distance migration.

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“…For instance, disturbance during low tide may have other effects than during high tide. Disturbance during low tide may not only cause energetic (flight) costs but also reduce food intake by shortening available foraging time or decreasing foraging efficiency (Rutten et al, 2010;Navedo et al, 2019). Furthermore, we did not measure to what extent birds avoided our roost sites, which is an important aspect of disturbance when considering population consequences (Mitchell et al, 1988;Gill et al, 2001;Bejder et al, 2009).…”

Section: Disturbance Frequencies and Energetic Costsmentioning

confidence: 99%

Cumulative energetic costs of military aircraft, recreational and natural disturbance in roosting shorebirds

Kolk

Krijgsveld

Linssen

et al. 2019

Animal Conservation

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Knowing the consequences of disturbance for multiple species and all disturbance sources is crucial to mitigate disturbance impacts in densely populated areas. However, studies that observe the complete disturbance landscape to estimate cumulative costs of disturbance are scarce. Therefore, we quantified responses, frequencies and energetic costs of disturbance of four shorebird species on five high tide roosts in the Wadden Sea. Roosts were located either in a military air force training area or were predominantly affected by recreational disturbance. In the military training area, infrequent transport airplanes and bombing jets elicited the strongest responses, whereas regular, predictable activities of jet fighters and small civil airplanes elicited far smaller responses. Disturbance occurred more frequently at roosts near recreational than near military activities, as recreation was prohibited in the military area during operation days. On average, birds took flight due to military, recreational or natural disturbance (e.g. raptors) 0.20-1.27 times per hour. High tide disturbance increased daily energy expenditure by 0.1%-1.4%, of which 51% was due to anthropogenic disturbance in contrast to natural disturbance. Costs were low for curlews Numenius arquata, oystercatchers Haematopus ostralegus and gulls Larus spp, but higherand potentially criticalfor bar-tailed godwits Limosa lapponica as they were most susceptible to aircraft and raptors. Given that bar-tailed godwits have previously been found to be least susceptible to walker disturbances, our results suggest that interspecific differences in susceptibility depend on disturbance source type. In our study area, aircraft disturbance impacts can be reduced by avoiding jet fighter activities during periods when high water levels force birds closer to military targets and by limiting bombing and transport airplane exercises.

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Assessing the effects of human activities on the foraging opportunities of migratory shorebirds in Austral high-latitude bays

Cited by 31 publications

References 69 publications

Seasonal survival and reversible state effects in a long‐distance migratory shorebird

Seasonal survival and reversible state effects in a long‐distance migratory shorebird

Oxidative status and metabolic profile in a long-lived bird preparing for extreme endurance migration

Cumulative energetic costs of military aircraft, recreational and natural disturbance in roosting shorebirds

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