The Dangerous Decline of Birds, Animals and Habitats We Love
No doubt you've noticed.
Our forests, landscapes and backyards look and feel somehow different than they were a decade ago. The songbirds sing less, the grasses look and feel unfamiliar and vines climb like giant webs strangling our favorite trees. The native plants, insects and wildlife are being taken over by foreign invaders and these non-natives are winning.
Fertilizers have altered the soil composition and foreign plants have been introduced to the area. The non-native plants have no insect or mammal predators to keep them under control. They're able to take over areas and create wastelands for native wildlife. So, the native plants no longer flourish and in some cases, are becoming extinct.
Rod Christie, the Executive Director of the Mianus River Gorge, explains it in the January 29th Outdoor Observer, and asks "Should We Accept the New Norm?"
He explains that there's some benefit to native birds because they provide structural nesting and a resting habitat. And native birds do eat their seeds. We know this because birds transport the seeds everywhere. Biologists believe these may be less nutritious.
But, most significantly, these non-native plants are not providing food for our native insects. If the native insects are not able to thrive, the non-native insects will continue to replace them and non-native animals will dominate.
Here's what Rod Christie writes:
"I recently saw a presentation by Doug Tallamy, University of Delaware, which pointed out that on any one native oak tree one may find thousands of caterpillars. And even more important, those thousands may be hundreds of different species. Why is this so important? Because many birds and other predators feed their young almost exclusively on high protein and fat containing caterpillars. Each spring they target specific native trees and shrubs to supply the thousands of caterpillars they need to raise a nest of young. And with a diversity of insect species on each tree, they are not out of luck if a certain insect population is low that year--they can mix and match to find the numbers they need.
On the other hand, a non-native species of tree like Ailanthus (tree of heaven) provides very little food for native insects. It just hasn’t been around long enough for native insects to figure out how to get past its toxic defenses to eat it. Therefore, Ailanthus thrives without any predators to help keep it under control. Ailanthus is also capable of suppressing competition with its allopathic chemicals, another great advantage. Ailanthus is more likely to be eaten by a non-native “invasive” species of insect from its native land like the recently reported invasive spotted lanternfly. Unfortunately, Ailanthus has evolved along with the lanternfly and has adapted to its predation. Even more unfortunate, the lanternfly eats Ailanthus during certain times of the year, but also is quick to adapt and eat native plants like apples, grapes, and other species as well.
With plants being the start of most food chains, non-natives are a dead end for native predators. With less insects there are fewer birds, small mammals, and so on all the way up the food chain. When natives are present, wildlife can easily feed and rear young, but non-natives actually function as a sink – sucking up time and energy without the food reward. The result is non-native plants that thrive without any insect or mammal predators to keep them under control, enabling them to take over areas and create dead zones for native wildlife."
What can we do?
1. Remove invasive plants and vines.
2. Replant with native species... but choose those that will do the most good. Oaks, cherry trees, willows, birch, and maple (Acer), which host great quantities of caterpillars.
3. Look for more information and encouragement in our upcoming newsletters and at our website www.somerslandtrust.org
Photo by Lauretta Jones