A positive relationship between spring temperature and productivity in 20 songbird species in the boreal zone

Abstract

Anthropogenic climate warming has already affected the population dynamics of numerous species and is predicted to do so also in the future. To predict the effects of climate change, it is important to know whether productivity is linked to temperature, and whether species' traits affect responses to climate change. To address these objectives, we analysed monitoring data from the Finnish constant effort site ringing scheme collected in 1987-2013 for 20 common songbird species together with climatic data. Warm spring temperature had a positive linear relationship with productivity across the community of 20 species independent of species' traits (realized thermal niche or migration behaviour), suggesting that even the warmest spring temperatures remained below the thermal optimum for reproduction, possibly due to our boreal study area being closer to the cold edge of all study species' distributions. The result also suggests a lack of mismatch between the timing of breeding and peak availability of invertebrate food of the study species. Productivity was positively related to annual growth rates in long-distance migrants, but not in short-distance migrants. Across the 27-year study period, temporal trends in productivity were mostly absent. The population sizes of species with colder thermal niches had decreasing trends, which were not related to temperature responses or temporal trends in productivity. The positive connection between spring temperature and productivity suggests that climate warming has potential to increase the productivity in bird species in the boreal zone, at least in the short term.

Phenology and productivity in a montane bird assemblage: Trends and responses to elevation and climate variation

“…Our finding of a positive productivity–temperature relationship is consistent with larger scale reports of positive avian productivity–temperature responses (Meller et al, ; Socolar et al, ) and suggests that projected climate trends may bode well for montane breeding birds in this region. Mild winter and spring temperatures may facilitate overwinter survival of insect prey and yield abundant early‐season insects (Bale et al, ).…”

“…Our finding of a positive productivity-temperature relationship is consistent with larger scale reports of positive avian productivitytemperature responses (Meller et al, 2018;Socolar et al, 2017) and…”

“…In some cases, wildlife populations may adapt to phenological shifts in food resources by tracking thermal niches in space (Chen, Hill, Ohlemüller, Roy, & Thomas, 2011) or time (Socolar, Epanchin, Beissinger, & Tingley, 2017). Although demographic mechanisms underlying such adaptations remain poorly understood, productivity of some species at upper ends of their thermal niches may benefit from warming trends (Meller, Piha, Vähätalo, & Lehikoinen, 2018;Scridel et al, 2018).…”

Behavioral responses to spring snow conditions contribute to long-term shift in migration phenology in American robins

“…One of the most pronounced and well-documented effects of global climate change has been the advancement of spring at high northern latitudes (Gray 2007), where temperatures are rising nearly two to three times faster than the global average (Gray 2007, Stocker et al 2013. This has caused alarm because of the important links between seasonal environmental dynamics and the phenology, reproductive success, and overall population health of many species (Moller et al 2008, Meller et al 2018. With some exceptions (e.g.…”

Warm temperatures during cold season can negatively affect adult survival in an alpine bird

“…In all cases, reproduction and survival are likely to be affected differently by the variation in environmental conditions in each season. For example, warmer springs and summers have been shown to positively influence reproduction in common alpine birds (Meller, Piha, Vähätalo, & Lehikoinen, ; Saracco, Desante, Siegel, Helton, & Stock, ), but to negatively impact the survival of common birds in a wider temperate context (Pearce‐Higgins, Eglington, Martay, & Chamberlain, ). The impact of some environmental conditions can also be delayed to “critical periods” in the seasonal cycle through carry‐over effects.…”