Pollinators, and the plants they rely on, can be highly susceptible to changes in the climate.
With warmer winter temperatures, the plants that pollinators rely on for feeding and raising young in the spring are tending to flower much earlier and often well before most insect species have even emerged.
This disparity in timing of emergence between the flowers and the pollinators that both rely on each other can lead to reduced feeding opportunities and reduced production of the next generation of pollinators and plants alike leading to an overall decline in biodiversity.
Drier and hotter spring and summers could also negatively affect the ability of mining bees to excavate their nesting burrows as the bare ground could become too hard and compacted and can also affect feeding opportunities as plants produce less nectar in hot dry weather.
Conversely cooler and wetter spring and summers negatively affect opportunities for insects to feed and collect pollen as they are less liable to fly in cool temperatures and inclement weather.
Insect pollinators have evolved over millennia with their chosen food plants and any climatic changes that affect their emergence and feeding and rearing of young will have a serious detrimental effect for both the plants and the pollinators they rely on.