Shifts in timing and duration of breeding for 73 boreal bird species over four decades

Abstract

Breeding timed to match optimal resource abundance is vital for the successful reproduction of species, and breeding is therefore sensitive to environmental cues. As the timing of breeding shifts with a changing climate, this may not only affect the onset of breeding but also its termination, and thus the length of the breeding period. We use an extensive dataset of over 820K nesting records of 73 bird species across the boreal region in Finland to probe for changes in the beginning, end, and duration of the breeding period over four decades (1975 to 2017). We uncover a general advance of breeding with a strong phylogenetic signal but no systematic variation over space. Additionally, 31% of species contracted their breeding period in at least one bioclimatic zone, as the end of the breeding period advanced more than the beginning. We did not detect a statistical difference in phenological responses of species with combinations of different migratory strategy or number of broods. Nonetheless, we find systematic differences in species responses, as the contraction in the breeding period was found almost exclusively in resident and short-distance migrating species, which generally breed early in the season. Overall, changes in the timing and duration of reproduction may potentially lead to more broods co-occurring in the early breeding season—a critical time for species’ reproductive success. Our findings highlight the importance of quantifying phenological change across species and over the entire season to reveal shifts in the community-level distribution of bird reproduction.

Combining range and phenology shifts offers a winning strategy for boreal Lepidoptera

“…During the last few decades, the mean temperature in Finland has risen by 0.2-0.4°C/decade (Mikkonen et al 2014; Fig. S1), with springs starting earlier and the timing of phenological events being advanced for many species (Helama et al 2020;Hällfors et al 2020). Therefore, we expect Lepidoptera to respond to changing climatic conditions by either shifting their ranges or adjusting their phenology in situ, or both.…”

Extreme temperatures compromise male and female fertility in a large desert bird

“…Research on the effects of natural temperature variation on reproduction in non-domesticated endotherms has primarily been on temperate species [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] . However, temperature unpredictability is greatest in tropical and sub-tropical regions and climate modelling shows this will increase in the future 13,34 .…”

“…The reproductive performance of species living in such regions may also be particularly sensitive to the effects of climatic fluctuations, as they often have prolonged breeding seasons that increase their risk of exposure to shifts in environmental conditions. Furthermore, because temperate species typically have short breeding seasons, timed to the seasonal appearance of food (phenology), there has been a focus on whether advancing spring temperatures reduce breeding success through phenological mismatches [18][19][20][21][22][23][24][25][26][27][28]35,36 . Consequently, more information is needed on the effects of ecologically relevant temperatures on investment in the traits directly related to fertility, such as the production and viability of eggs and sperm.…”

Predicting Thermal Adaptation by Looking Into Populations’ Genomic Past

“…From a biotic perspective, among-ecotype differentiation ( Cortés et al, 2012a , b , 2013 ; Blair et al, 2016 ), intrapopulation divergence ( Cortés et al, 2011 ; Blair et al, 2012 , 2018 ; Kelleher et al, 2012 ), and within-family variation ( Galeano et al, 2012 ; Blair et al, 2013 ) could encourage or coerce adaptation. Population’s functioning, abundance, distribution, and diversity, as predicted from controlled experiments ( Way and Oren, 2010 ; Elmendorf et al, 2012 ; Wolkovich et al, 2012 ; Andresen et al, 2016 ; Becklin et al, 2017 ; Singh et al, 2017 ), experimental evolution ( Tenaillon et al, 2012 ; Mallard et al, 2018 ; Pfenninger and Foucault, 2020 ), biological monitoring ( Walther et al, 2002 ; Franks et al, 2013 ; Wipf et al, 2013 ; Reichstein et al, 2014 ; Hällfors et al, 2020 ), and shifts observed in the fossil record ( Alsos et al, 2009 ; Willis and MacDonald, 2011 ; Lyons et al, 2016 ; Bruelheide et al, 2018 ), can feed back on climate change ( Pearson et al, 2013 ) and so be considered as drivers themselves. Regardless of the exact nature and extent of the data type, both GP and ML may offer suitable scenarios to merge diverse, and even conflicting, data sources in order to pinpoint emergent properties ( Street et al, 2011 ) out of a complex system, as is thermal genomic adaptation.…”