Fall has a resurgence of some spring activity but has its own unique ephemerals. Anxiously we wait for the fall color pageant. By August, cherry trees were dropping red and yellow leaves and sugar maples began releasing some green leaves.
The Michigan Botanical Club visited Ody Brook Nature Sanctuary, on September 19, and witnessed 1200-1500 Clouded Sulphur butterflies flying over and among Frost Asters, in the field. Of the 40 people present, most said they have never seen so many butterflies in one area. It was a great, moving experience lasted through most of September and continues into October. After killing frosts, asters are mowed annually, in late October, to prepare the area for the ephemeral spring mating display of American Woodcocks. Also present were some Orange Sulphurs that hold off making an appearance until late in the year. We work to manage the sanctuary for greatest habitat biodiversity.
Fall flowering species of showy yellow goldenrods were observed in sunlit openings. Ragweeds with small unnoticed green flowers bloom at the same time. It is ragweed’s ephemeral, small, lightweight pollen carried on the wind that causes “hay fever.” Unfortunately, many people blame goldenrods because their fall ephemeral flowering occurs at the same as ragweed. Goldenrod pollen is large, heavy and falls to the ground. Goldenrod depends on insects to carry its pollen to other flowers and is not a source of “hay fever.”
A small fall resurgence of spring flowering maiden pinks shows pink petals with white dots and fringed petal tips. As daylight hours shorten and night lengthens, spring and summer plant physiology is confused and causes a slight increase in plant hormone levels that stimulates some out-of-season flowering. It is normal for fall flowering plants to have their full plant hormones increase late to stimulate fall flowering. Spring flowering plant schedules are completed because of earlier hormone peaks but a hormone resurgence stimulated by night length similar to spring brings about some out-of-season blooming.
Even animals like spring peeper frogs have a late season hormone rise that stimulates some breeding behavior. One will hear scattered peeping throughout the woods but the frogs do not migrate to their essential fishless breeding vernal ponds to lay eggs like they do in April and May. Gray tree frogs call with their short loud trilling burst from the woods. Of course, deer begin their ephemeral rut.
Bird migration time varies among species and is partly driven by hormone level changes. Many shorebird species migrate south as early as July. Warblers move through from August to October. Interestingly, it is the first year young birds that come through ahead of parents.
Bur Oak is an ephemeral of centuries, with its coming and going in Michigan, where remnants still survive. It has become less common due to habitat change. It thrives and reproduces best in grasslands, with widely scattered trees known as savannas. It has adaptations to survive periodic fires. We have largely stopped wildfires and the tree is in decline as savannas disappear. With periodic fires, savanna habitat supports conditions where this species can increase.
Nature niches have yearly ephemerals and others that occur over centuries (probably not technically classified as ephemerals). Some species are “ephemeral” that come and go over centuries, depending on adaptations to events like essential fires. Our lives are too short to witness all the ephemeral wonders around us.
Natural history questions or topic suggestions can be directed to Ranger Steve (Mueller) at firstname.lastname@example.org – Ody Brook Nature Sanctuary, 13010 Northland Dr. Cedar Springs, MI 49319 or call 616-696-1753.