| Abstract | Future climatic scenarios forecast increases in average temperatures as well as in the
frequency, duration, and intensity of extreme events, such as heatwaves. Whereas behavioral
adjustments can buffer direct physiological and fitness costs of exposure to
excessive temperature in wild animals, these may prove more difficult during specific
life stages when vagility is reduced (e.g., early developmental stages). By means of a
nest cooling experiment, we tested the effects of extreme temperatures on different
stages of reproduction in a cavity-nesting
Mediterranean bird of prey, the lesser kestrel
(Falco naumanni), facing a recent increase in the frequency of heatwaves during
its breeding season. Nest temperature in a group of nest boxes placed on roof terraces
was reduced by shading them from direct sunlight in 2 consecutive years (2021
and 2022). We then compared hatching failure, mortality, and nestling morphology
between shaded and non-shaded
(control) nest boxes. Nest temperature in control
nest boxes was on average 3.9°C higher than in shaded ones during heatwaves, that
is, spells of extreme air temperature (>37°C for >=2 consecutive days) which hit the
study area during the nestling-rearing
phase in both years. Hatching failure markedly
increased with increasing nest temperature, rising above 50% when maximum nest
temperatures exceeded 44°C. Nestlings from control nest boxes showed higher mortality
during heatwaves (55% vs. 10% in shaded nest boxes) and those that survived
further showed impaired morphological growth (body mass and skeletal size). Hence,
heatwaves occurring during the breeding period can have both strong lethal and sublethal
impacts on different components of avian reproduction, from egg hatching
to nestling growth. More broadly, these findings suggest that the projected future
increases of summer temperatures and heatwave frequency in the Mediterranean
basin and elsewhere in temperate areas may threaten the local persistence of even
relatively warm-adapted
species |
| Authors | Alejandro Corregidor-Castro1,2 | Jennifer Morinay3,4 | Susan E. McKinlay5 | Samuele Ramellini5 | Giacomo Assandri3,6 | Gaia Bazzi3 | Alexandra Glavaschi1 | Enrico L. De Capua7 | Alessandro Grapputo1,8 | Andrea Romano5 | Michelangelo Morganti2 | Jacopo G. Cecere3 | Andrea Pilastro1,8 | Diego Rubolini2,5 |
| Text | 484809 2023 early development extreme temperature heat stress heatwaves nest microclimate temperature manipulation Experimental nest cooling reveals dramatic effects of heatwaves on reproduction in a Mediterranean bird of prey Alejandro Corregidor Castro1,2 Jennifer Morinay3,4 Susan E. McKinlay5 Samuele Ramellini5 Giacomo Assandri3,6 Gaia Bazzi3 Alexandra Glavaschi1 Enrico L. De Capua7 Alessandro Grapputo1,8 Andrea Romano5 Michelangelo Morganti2 Jacopo G. Cecere3 Andrea Pilastro1,8 Diego Rubolini2,5 1Dipartimento di Biologia, Universita degli Studi di Padova, Padova, Italy 2Consiglio Nazionale delle Ricerche Istituto di Ricerca sulle Acque CNR IRSA , Brugherio, Italy 3Area Avifauna Migratrice, Istituto Superiore per la Protezione e la Ricerca Ambientale ISPRA , Bologna, Italy 4Centre for Biodiversity Dynamics, Institutt for Biologi, NTNU, Trondheim, Norway 5Dipartimento di Scienze e Politiche Ambientali, Universita degli Studi di Milano, Milan, Italy 6Department of Life Sciences and System Biology, University of Turin, Turin, Italy 7Provincia di Matera Parco della Murgia Materana, Matera, Italy 8National Biodiversity Future Centre, Palermo, Italy Future climatic scenarios forecast increases in average temperatures as well as in the frequency, duration, and intensity of extreme events, such as heatwaves. Whereas behavioral adjustments can buffer direct physiological and fitness costs of exposure to excessive temperature in wild animals, these may prove more difficult during specific life stages when vagility is reduced e.g., early developmental stages . By means of a nest cooling experiment, we tested the effects of extreme temperatures on different stages of reproduction in a cavity nesting Mediterranean bird of prey, the lesser kestrel Falco naumanni , facing a recent increase in the frequency of heatwaves during its breeding season. Nest temperature in a group of nest boxes placed on roof terraces was reduced by shading them from direct sunlight in 2 consecutive years 2021 and 2022 . We then compared hatching failure, mortality, and nestling morphology between shaded and non shaded control nest boxes. Nest temperature in control nest boxes was on average 3.9°C higher than in shaded ones during heatwaves, that is, spells of extreme air temperature >37°C for >=2 consecutive days which hit the study area during the nestling rearing phase in both years. Hatching failure markedly increased with increasing nest temperature, rising above 50% when maximum nest temperatures exceeded 44°C. Nestlings from control nest boxes showed higher mortality during heatwaves 55% vs. 10% in shaded nest boxes and those that survived further showed impaired morphological growth body mass and skeletal size . Hence, heatwaves occurring during the breeding period can have both strong lethal and sublethal impacts on different components of avian reproduction, from egg hatching to nestling growth. More broadly, these findings suggest that the projected future increases of summer temperatures and heatwave frequency in the Mediterranean basin and elsewhere in temperate areas may threaten the local persistence of even relatively warm adapted species Published version Articolo in rivista Blackwell Science. 1354 1013 Global change biology Print Global change biology Print Glob. chang. biol. Print RUBOLINI DIEGO michelangelo.morganti MORGANTI MICHELANGELO |
