This week we had the opportunity to visit the Detroit Zoo. We arrived at 9 am and had three hours of free time to explore the many exhibits which make up the zoo. During this time we learned about ongoing conservation efforts, rescue and rehabilitation of animals kept in garages or smuggled into the US, and the many, many invasive species which call the zoo home.
Walking around invasive plants were practically slapping us in the face. Garlic mustard, buckthorn, honeysuckle, tree of heaven, autumn olive, and lily of the valley just to name a few. We were shocked, but soon after lunch at the Arctic Overlook we understood why this was the case.
On a behind the scenes tour with a member of the landscaping team it was made perfectly clear that the animals come first, no matter what. They didn’t pull or spray invasive plants if they didn’t hurt the animals, following the old “if it ain’t broke, don’t fix it” adage.
However, some invasive plants have become invaluable to the zoo staff, and the animals. With literally tons of food being consumed every day, any edible plant they find gets used. The same mulberries which litter the walkways and picnic tables are the ones which end up as food for birds and some mammals. But what happens after the animals have eaten all this food?
That’s right! POO POWER. Three days a week the deposits are deposited into one of four chambers in the anaerobic digester. A bacterial culture is sprayed on the 30 yards of material, and the sealed chamber is heated at 105 degrees Fahrenheit for 28 days. The end result, a lot of methane gas. One day they hope to perfect this method and use the gas to power the animal hospital, and sell the decomposed organic matter as fertilizer to their household members throughout the Detroit metro area.