Thursday, May 03, 2012
FOPOS Speaker Focuses On Deer
He speculates that this imbalance, and the severe browsing pressure on native vegetation that it creates, is without precedent in history. If deer numbers had been so high in the past, native wildflowers like the swamp pink would never have evolved growth strategies that now make them extremely vulnerable to decimation by intense browsing.
Earthworms, too, though beneficial in a vegetable garden, turn out to be destructive in natural areas. He described the imported European earthworms as being slow-moving. Asian species have a higher metabolism.
How would deer and invading earthworms impact forest soil health and even contribute to climate change? If there are too many deer, they eat all the native shrubs that were deepening the shade on the forest floor. Sunlight warms the less-shaded soil as much as 10 degrees above normal, stimulating increased worm activity. The worms consume last year's leaf litter faster, reducing soil organic matter that would otherwise have absorbed rainfall, sequestered carbon and provided habitat for soil organisms.
Part of Emile's power as a speaker comes from his talent for intermingling comedy with tragedy. His stories about neighbors' reactions to his anti-lawn landscaping had the audience convulsing in laughter.
Princeton's open space is better off than many woodlands elsewhere in NJ. Annual deer culling since 2000 by the township has helped reduce browsing pressure enough to allow a resurgence of native shrubs like spicebush. But until deer numbers are reduced to at most 20 per square mile (5-10 is better), the forests will not be able to heal.