Maintenance of temporal synchrony between syrphid flies and floral resources despite differential phenological responses to climate

Abstract

Variation in species' responses to abiotic phenological cues under climate change may cause changes in temporal overlap among interacting taxa, with potential demographic consequences. Here, we examine associations between the abiotic environment and plant-pollinator phenological synchrony using a long-term syrphid fly-flowering phenology dataset (1992-2011). Degree-days above freezing, precipitation, and timing of snow melt were investigated as predictors of phenology. Syrphids generally emerge after flowering onset and end their activity before the end of flowering. Neither flowering nor syrphid phenology has changed significantly over our 20-year record, consistent with a lack of directional change in climate variables over the same time frame. Instead we document interannual variability in the abiotic environment and phenology. Timing of snow melt was the best predictor of flowering onset and syrphid emergence. Snow melt and degree-days were the best predictors of the end of flowering, whereas degree-days and precipitation best predicted the end of the syrphid period. Flowering advanced at a faster rate than syrphids in response to both advancing snow melt and increasing temperature. Different rates of phenological advancements resulted in more days of temporal overlap between the flower-syrphid community in years of early snow melt because of extended activity periods. Phenological synchrony at the community level is therefore likely to be maintained for some time, even under advancing snow melt conditions that are evident over longer term records at our site. These results show that interacting taxa may respond to different phenological cues and to the same cues at different rates but still maintain phenological synchrony over a range of abiotic conditions. However, our results also indicate that some individual plant species may overlap with the syrphid community for fewer days under continued climate change. This highlights the role of interannual variation in these flower-syrphid interactions and shows that species-level responses can differ from community-level responses in nonintuitive ways.

Spatiotemporal snowmelt patterns within a high Arctic landscape, with implications for flora and fauna

“…Taxa dependent on sporadic (late season) resources such as scat, fungal fruiting bodies, or carrion prove more or less unresponsive to snowmelt pattern, suggesting a stronger response to resources rather than local environmental conditions. A strong imprint of snowmelt date was also observed in the phenological timing of many dipteran pollinator groups, in line with previous studies (Iler et al 2013). Muscid flies at Zackenberg show a general decline in abundance during the past two decades, but patterns among individual species are highly dissimilar (Loboda et al 2017).…”

“…Indeed, plant and insect populations may be strongly affected by small-scale variation (Badik et al 2015), and the local timing of snowmelt has been proposed to have a major influence on local species occurrence (Leingärtner, Krauss, and Steffan-Dewenter 2014). Yet research on the impact of snow conditions on phenology typically uses average conditions: temperature and snow conditions characterized by either single weather stations for large areas or by longer-term averages across sites (Høye et al 2014;Iler et al 2013;Kudo and Ida 2013). Conflicting with such descriptions is the finding that the exact timing of snowmelt will vary in space and time, with spatiotemporal consistency likely affecting consistency in the timing of local phenological events and demographic processes (Bowden et al 2015b).…”

Potential Disruption of Pollination in a Sexually Deceptive Orchid by Climatic Change

“…Differing phenological responses of individual species to climate warming may lead to the breakdown of coevolved and incidental interactions between species [19][20][21][22], because they respond either to different cues or to the same cues at different rates [23]. Highly coevolved insect pollination systems, in which cross-pollination is entirely reliant on one or two pollinator species [24], could be particularly susceptible to disruption by climatic warming.…”

Climatic Risk and Distribution Atlas of European Bumblebees

“…Kudo & Ida, 2013;Petanidou et al, 2014), even if several empirical studies suggest that the large plant and insect biodiversity could mitigate the expected dramatic consequences (e.g. Bartomeus et al, 2011Bartomeus et al, , 2013bForrest & Thomson, 2011;Iler et al, 2013). Such changes in pollinator communities may not only affect wild plants but can also impact important agricultural crops (e.g.…”