… flowering period of certain plants (e.g. hazel, alder) and thus the pollen season now begin much earlier than in the past 20 to 30 years. Phenological observations … or fungal species) in the environment can affect human health. Among the better known water-borne and potentially dangerous bacteria are cyanobacteria ("blue-green … flowering period of certain plants (e.g. hazel, alder) and thus the pollen season now begin much earlier than in the past 20 to 30 years. Phenological observations …