Local species threatened by backyard invaders, lack of open space

A report from a statewide task force warns that the proliferation of invasive plant species and a rapid decline of wildlands are causing severe damage to Delaware's ecosystem, and calls on government, businesses and individuals to help fix the problems.

The Ecological Extinction Task Force report, published Dec. 1, draws on months of hearings and expert testimony to offer dozens of recommendations aimed at improving land management practices, safeguarding local ecosystems and reversing a trajectory that has brought swaths of local species near or past the point of extinction.

Sen. Stephanie Hansen, D-Middletown, championed the issue in the General Assembly and chaired the task force.

"These recommendations couldn't come at a more important time," she said. "Over the past few decades, we have actively and unwittingly introduced dozens of non-native and invasive species into this area. Those species are threatening damage to the foundations of our food chain that would be catastrophic to our ecosystem. We have to take action before it's too late. In such a small state, each of us can make a huge difference just by making simple changes at home. Our mission now is to change how we perceive this issue, educate Delawareans on the problem, and create incentives for them to be part of the solution."

Hansen was inspired by research from Dr. Douglas Tallamy, a professor in the University of Delaware's College of Agriculture and Natural Resources. A leading scholar on local extinction, Tallamy stressed that human life depends on biodiversity and that humans have driven half of all plant and animal species on the planet into extinction in just the past few decades.

"For our own good, we must abandon the age-old notion that humans are 'here' and nature is someplace else," he said. "Every time we reduce a species' population, or force it to local extinction, we degrade our own life-support systems. We must end such short-sighted treatment of the life around us. The wild things around us control pests, pollinate our plants, produce oxygen, manage our watersheds, sequester carbon, build topsoil, and create all of the other ecosystem services that enable humans to survive on earth. And ecosystems do these things better when they house more species."

The report calls for a number of corrective steps, including:

• A sustained educational campaign targeted at everyone from students to homeowners and landscape designers
• Government leadership by example, including public land management reform
• Incentives for private landowners to buy and plant native species
• Full funding of existing open space programs
• Higher deer harvests
• A phased-in ban on the sale of invasive species
• Creation of a Native Species Commission to implement recommendations and report annually to the General Assembly.

Most steps focus on replenishment of native plant species, which have been displaced by lawns, non-native ornamental plants, and invasive species. Common invasive species include Asian varieties of honeysuckle and stiltgrass, Norway maples and rapidly spreading weeds that outcompete native plants and dominate their surroundings. These species do not contribute to the local food supply and are killing off plants that do.

Tallamy's research shows that 90 percent of herbivorous insects have evolved to eat specific vegetation from their native habitat. The loss of their food supply has resulted in cascading food shortages for larger species including birds, reptiles and fish. Coupled with the loss and fragmentation of woodlands and animal habitats around the state, this has caused rapid declines or disappearances of 20 percent of local fish species; 31 percent of local reptile and amphibian species; 40 percent of local plant species; and 41 percent of local bird species that rely on forest cover, including a 50 percent population loss among some species.

Rep. Ronald Gray, R-Selbyville, praised efforts to educate Delaware residents about the threats posed by invasive species.

"I enjoyed serving on the Ecological Extinction task force over the past few months. I learned quite a bit about how non-native and invasive plants can affect native plants and animals in Delaware," said Gray. "I support an ongoing effort to educate the public and work with businesses in the landscape disciplines to provide the best choices for consumers that will protect and maintain the viability of native plants and animals in our state."