Climate change

The effect of climate change on pollinators is still largely unknown. However, leading entomologists, ecologists, and researchers in the field all agree that the biggest effect will be on pollinator-plant synchronicity.  The concern is that weather pattern changes may cause changes in blooming periods, which would put pollinators out of sync with their forage species.  The magnitude of this threat is hard to anticipate as many of the environmental and genetic cues used by the plants and pollinators remain a mystery.

Some research suggests that, for some species, changes in the onset of flowering and first appearance dates of pollinators have advanced linearly, and therefore occurred at parallel magnitudes.  In such instances,climate change would alter the relationship as a whole, with each shift being felt by both attributes keeping the equilibrium in the relationship between pollinator and plant.

High altitude climates may be one of the habitats where it seems climate change is having the largest effects. Here plant flowering is usually cued by snow melt, which is very likely to be affected by climate change.

Case Study: Climate change effects on erythronium grandiflorum, a thirty year study

Premise of the study: From 1975 to 2008, a series of plots in the Rocky Mountains of Colorado were visited every other day during late May to early September to observe a number of flowering phenology variables.  For this same period of time, temperature and precipitation data was obtained from a weather station nearby and snow-pack data was collected. Using this climatic data, mean temperatures, precipitation, and the day of “snow-melt” for each year could be calculated.

Key results:  Over the 30 year study period, the snow-melt date advanced 4.14 days per decade and mean summer temperatures increased by 0.38 degrees Celsius each decade. First, peak, and last flowering dates of E.grandiflorum advanced an average of 3.2 days per decade.

Conclusion: Snow-melt is arriving earlier, causing earlier flowering of E.grandiflorum. This shift may have an effect on the synchronized relationship that the plant and its pollinator have.  Considering the bloom is only open for 7 days, if the pollinators are not also experiencing a similar shift in first appearance dates, the window of opportunity for pollination is almost cut in half.

Because it is one of the first species to bloom in the spring and if emergence rates or migratory patterns have not also shifted, newly emerged bumble bee queens and newly arrived migratory hummingbirds may undergo a reduction in resource availability due to mistiming.

No data was collected for pollinators during this study. Therefore no conclusions on pollinator-plant synchronicity can be drawn.