Climate variation and regional gradients in population dynamics of two hole-nesting passerines

Abstract

Latitudinal gradients in population dynamics can arise through regional variation in the deterministic components of the population dynamics and the stochastic factors. Here, we demonstrate an increase with latitude in the contribution of a large-scale climate pattern, the North Atlantic Oscillation (NAO), to the fluctuations in size of populations of two European hole-nesting passerine species. However, this influence of climate induced different latitudinal gradients in the population dynamics of the two species. In the great tit the proportion of the variability in the population fluctuations explained by the NAO increased with latitude, showing a larger impact of climate on the population fluctuations of this species at higher latitudes. In contrast, no latitudinal gradient was found in the relative contribution of climate to the variability of the pied flycatcher populations because the total environmental stochasticity increased with latitude. This shows that the population ecological consequences of an expected climate change will depend on how climate affects the environmental stochasticity in the population process. In both species, the effects will be larger in those parts of Europe where large changes in climate are expected.

Rainfall, leafing phenology and sunrise time as potential Zeitgeber for the bimodal, dry season laying pattern of an African rain forest tit (Parus fasciiventer)

“…This general pattern has been studied in considerable detail (e.g., Lack 1966;Perrins 1979;Blondel et al 1990Blondel et al , 2006Nager and van Noordwijk 1995;Ramsay and Otter 2007;Lehmann et al 2012), enabling researchers to examine the effects of climate change on breeding seasonality and population dynamics at north temperate latitudes (Visser et al 1998Saether et al 2003;Both et al 2004;Nussey et al 2005;Visser et al 2006;Charmantier et al 2008;Visser et al 2010;Reed et al 2013;Gienapp et al 2014), where the two main proximate cues for egg laying-day length and temperaturevary markedly throughout the year. Most passerines live at tropical or sub-tropical latitudes, however, where seasonal variation in these cues is much less pronounced and breeding activity is often considered to be relatively aseasonal, particularly in rain forest habitats.…”

Cascading climate effects and related ecological consequences during past centuries

“…Additional factors, for example changes of the woodland habitat (whether climate related or not), density dependent variation in reproductive parameters, or variation in predation rates, likely have superimposed, but not concealed, the effect of the large-scale atmospheric circulation (see also Saether et al, 2007). We conclude that the causal chain linking large-scale atmospheric oscillations to individual life history traits, as given in the analysis part, provides an explanation for the fundamental importance of climate factors for the continent-wide spatio-temporal dynamics of the great tit (Saether et al, 2003(Saether et al, , 2007. Combining ecological and paleoclimatological data improves insight in how global atmospheric oscillations and related climate variations determine crucial components of variance in ecosystem structure and functionality from the largest spatio-temporal scale down to the individual level.…”

“…Due to lack of perfectly independent data we used great tit breeding data from a distant population that was likely living under similar influence of the NAO/NCP system (Saether et al, 2003;Both et al, 2004). Thus, we cannot fully exclude collinearity with other factors, however, consider this very unlikely.…”

“…Due to the scarceness of data, climate impacts have rarely been tracked down to key parameters of population dynamics such as reproductive (Saether et al, 2003) or survival rates (Catchpole et al, 2000;Grosbois et al, 2006). Consequently, both the history and future of climate forcing on ecosystem function remain highly debated (Martin, 2007).…”

“…The effects of large-scale, fundamental climatic forcing (through atmospheric circulation patterns) on local habitat and the phenology of species may vary over relatively small areas (Saether et al, 2003;Both et al, 2004), and the effect size may vary substantially amongst populations of a species since both the underlying trophic interactions and the plasticity of systems may differ (Visser et al, 2002;Both et al, 2004;Sanz, 2006, 2009;Martin, 2007;Charmantier et al, 2008). Due to the scarceness of data, climate impacts have rarely been tracked down to key parameters of population dynamics such as reproductive (Saether et al, 2003) or survival rates (Catchpole et al, 2000;Grosbois et al, 2006).…”