Reproductive parameters of tropical lesser noddies respond to local variations in oceanographic conditions and weather

Abstract

Keywords:breeding phenology chick mass gain chlorophyll-a fledging success Indian Ocean dipole mode ocean primary productivity sea surface temperature Regional terms:Western Indian Ocean Seychelles Anous tenuirostris a b s t r a c t Most attempts to link seabirds and climate/oceanographic effects have concerned the Atlantic and Pacific Oceans with comparatively few studies in the tropical Indian Ocean. This paper examines the reproductive response of the lesser noddy Anous tenuirostris to temporal fluctuations in oceanographic and climatic conditions using 8 years of monitoring data from Aride Island (Seychelles), tropical Western Indian Ocean. We tested the hypothesis that breeding parameters (mean hatching date, mean egg size, hatching and fledging successes) and chick growth are influenced by local, seasonal oceanographic conditions as expressed by ocean primary productivity (surface chlorophyll-a concentrations; CC), sea surface temperature (SST) and wind speed. We also examined the relationship between lesser noddy breeding parameters and climate conditions recorded at the basin-wide scale of the Indian Ocean (Indian Ocean Dipole Mode Index, DMI). Our findings suggest that birds had a tendency to lay slightly larger eggs during breeding seasons (years) with higher CC during AprileJune (pre-laying, laying and incubation periods). Hatching date was positively related to SST in AprileJune, with the regression parameters suggesting that each 0.5 C increase in SST meant a delay of approx.10 days in hatching date. A negative linear relationship was also apparent between hatching success and SST in JuneeAugust (hatching and chick-rearing periods), while the quadratic regression models detected a significant effect of wind speed in JuneeAugust on fledging success. Body mass increments of growing chicks averaged over 7-day periods were positively related with (2-week) lagged CC values and negatively related with (2-week) lagged SST values. No significant relationship between DMI and lesser noddy breeding parameters was found, but DMI indices were strongly correlated with local SST. Altogether, our results indicate that the reproduction of this top marine predator is dictated by fluctuations in local environmental conditions around the colony, while the effects of large-scale oceanographic processes (DMI) on our study population might be mediated by an effect on local SST.

Potential climate-driven changes to seabird demography: implications for assessments of marine renewable energy development

“…In only one species (northern gannet) was breeding success predicted to increase under the future climate scenario. Our results build upon previous findings that have demonstrated the importance of climate on breeding success and other vital rates in seabirds globally, but which have tended to focus on single breeding colonies or species (Jones et al 2007, Barbraud et al 2011, Jenouvrier et al 2014, Monticelli et al 2014, Carroll et al 2015, Christensen-Dalsgaard et al 2018; but see Sydeman et al 2021) or on abundance, not vital rates (Johnson et al 2013). Very few studies have estimated future vital rates for seabirds under projected future climates (but see Carroll et al 2015) or across broad regions such as the North Sea (but see recent review by Pearce-Higgins 2021).…”

“…Previous studies have identified relationships between seabird breeding success and climate variables including terrestrial temperature and precipitation (Smith & Gaston 2012, Watanuki & Ito 2012, Christensen-Dalsgaard et al 2018, Michielsen et al 2019 as well as marine climate variables including spring North Atlantic Oscillation (NAO), winter NAO, sea surface temperature (SST) and sea surface salinity (SLM) (Jones et al 2007, Watanuki & Ito 2012, Monticelli et al 2014, Carroll et al 2015. Terrestrial winter temperature and rainfall have been linked to survival in seabirds, thought to be driven by physiological stress arising from more extreme weather conditions, such as cooler and wetter phases increasing exposure risk (Smith & Gaston 2012) as well as high terrestrial temperatures during breeding causing heat stress (Smith & Gaston 2012, Michielsen et al 2019.…”

Individual Consistency and Phenotypic Plasticity in Rockhopper Penguins: Female but Not Male Body Mass Links Environmental Conditions to Reproductive Investment

“…Local SSTA represent a different spatial scale and thus reflect environmental conditions close to the colony. All three variables have previously shown to affect either breeding biology or population dynamics of other seabird species, including (rockhopper) penguins [ 54 – 60 ].…”