Large‐scale spatial variation in feather corticosterone in invasive house sparrows (Passer domesticus) in Mexico is related to climate

Ecology and Evolution

Gillian D. Treen¹  Keith A. Hobson¹  Tracy A. Marchant¹ 

[1] Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada

关键词: Climate;    corticosterone;    ecophysiology;    feather CORT;    invasive species;    macrophysiology;    Mexico;    Passer domesticus;    precipitation;    temperature;   

DOI  :  10.1002/ece3.1638

来源: Wiley

【 摘 要 】

Abstract

Ecologists frequently use physiological tools to understand how organisms cope with their surroundings but rarely at macroecological scales. This study describes spatial variation in corticosterone (CORT) levels in feathers of invasive house sparrows (Passer domesticus) across their range in Mexico and evaluates CORT–climate relationships with a focus on temperature and precipitation. Samples were collected from 49 sites across Mexico. Feather CORT (CORT_f) was measured using methanol-based extraction and radioimmunoassay. Relationships between CORT_f and spatial and climate variables were examined using simple linear regressions. Ordination was used on climate data, CORT_f was plotted against the resulting axes, and univariate regression trees were used to identify important predictors of CORT_f. Universal kriging interpolation was used to illustrate spatial variation in CORT_f across Mexico. Correlations with ordination axes showed that high CORT_f was associated with low precipitation during the rainy season and low dry season temperatures. Specifically, CORT_f was negatively related to May precipitation and January and July minimum temperatures, and positively related to April deuterium excess and June minimum temperatures. CORT_f was higher in second-year birds compared to after-hatch years and after-second years. House sparrows had higher CORT_f levels in the hot, dry, north-central region of Mexico, and CORT_f was negatively related to temperature and precipitation. House sparrows molt primarily from August–September but climate conditions throughout the year were important predictors of CORT_f, suggesting that conditions outside of molt can carry over to influence energetics during feather growth. These data suggest that dry conditions are challenging for house sparrows in Mexico, supporting previous work showing that precipitation is an important predictor of broad-scale CORT variation. This work highlights the utility of CORT_f for evaluating the influence of physiology on current avian range limits; furthermore, these data may allow us to predict future changes in species distributions.

【 授权许可】

CC BY   
© 2015 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.

Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.