Detecting mismatches of bird migration stopover and tree phenology in response to changing climate

Abstract

Migratory birds exploit seasonal variation in resources across latitudes, timing migration to coincide with the phenology of food at stopover sites. Differential responses to climate in phenology across trophic levels can result in phenological mismatch; however, detecting mismatch is sensitive to methodology. We examined patterns of migrant abundance and tree flowering, phenological mismatch, and the influence of climate during spring migration from 2009 to 2011 across five habitat types of the Madrean Sky Islands in southeastern Arizona, USA. We used two metrics to assess phenological mismatch: synchrony and overlap. We also examined whether phenological overlap declined with increasing difference in mean event date of phenophases. Migrant abundance and tree flowering generally increased with minimum spring temperature but depended on annual climate by habitat interactions. Migrant abundance was lowest and flowering was highest under cold, snowy conditions in high elevation montane conifer habitat while bird abundance was greatest and flowering was lowest in low elevation riparian habitat under the driest conditions. Phenological synchrony and overlap were unique and complementary metrics and should both be used when assessing mismatch. Overlap declined due to asynchronous phenologies but also due to reduced migrant abundance or flowering when synchrony was actually maintained. Overlap declined with increasing difference in event date and this trend was strongest in riparian areas. Montane habitat specialists may be at greatest risk of mismatch while riparian habitat could provide refugia during dry years for phenotypically plastic species. Interannual climate patterns that we observed match climate change projections for the arid southwest, altering stopover habitat condition.

Spring plant phenology and false springs in the conterminous US during the 21st century

“…The onset of spring plant growth, or 'spring onset,' has shifted earlier in the year in recent decades amid rising global temperatures (Cleland et al 2007, Ault et al 2011, McCabe et al 2012. Whereas a longer growing season may increase carbon uptake and potentially mitigate climate change (Black et al 2000, Dragoni et al 2011, earlier leaf and flower emergence has led to phenological mismatches between plant resources and many of those animals depending upon them (Walther et al 2002, Schweiger et al 2008, Saino et al 2011, Burkle et al 2013, Kellermann and van Riper IIIrd 2015. Earlier spring onset can also lead to increased risk of false springs, when subsequent hard freezes damage new, vulnerable plant growth in ecological and agricultural systems (Cannell and Smith 1986, Inouye 2008, Knudson 2012.…”

Micro-scale environmental variation amplifies physiological variation among individual mussels

“…Mean temperatures and the frequency of extreme weather events are predicted to continue increasing [2,3], likely reducing the mean performance of species [4,5]. Such global trends will interact with regional factors, such as spatial variation in climatic patterns or the timing of low tides [6,7], in sometimes complex and nonlinear ways [8]. In addition, evolutionary responses to environmental change can act over short time scales once thought to be the exclusive realm of ecological interactions and/or phenotypic plasticity [9,10], with important implications for species' abilities to resist and adapt to global change.…”

Extreme variations in spring temperature affect ecosystem regulating services provided by birds during migration

“…Our first objective was to determine patterns of coincidence in arrival and foraging behavior of three migratory wood-warbler species (Parulidae) with that of tree phenology. Although studies in other systems of North America have identified important tree phenophases that overlap with migratory bird stopover (e.g., Rodewald and Brittingham 2007, McGrath et al 2008, Strode 2009, Kellermann and van Riper III 2015, Wood and Pidgeon 2015, these relationships remain unclear in the oak savanna system of this study. Our second objective was to quantify the effect of the extreme difference in spring temperature on potential ecosystem regulating services that migratory birds provide.…”