THIRD ANNUAL LONG ISLAND NATURAL HISTORY CONFERENCE
Novel ecosystems: a threat to wildlife
Marilyn J. Jordan, Ph.D., Retired Senior Conservation Scientist, The Nature Conservancy, Cold Spring Harbor, NY
Novel ecosystems — new, historically unprecedented combinations of species — occupy ~40% of the terrestrial ice-free globe. Novel ecosystems are created by human land use practices, abandonment of agricultural lands, introduction of invasive species, loss of native species, pollution, and global climate change.
As the proportion of non-native plant species in an ecosystem increases there typically is a decrease in native plant species diversity and biomass. Most herbivorous insect species are specialists and can feed on only one, or very few, species of native plants. As novel ecosystems containing a hodgepodge of non-native plants from around the world become widespread we risk losing about 90% of native insect herbivores.
Insects are a critical part of food webs because they convert plants into nutritious packages of insect protein and fat essential for a wide range of wildlife species. Loss of insect food sources undermines food webs and probably reduces the health and abundance of many wildlife species. Such effects are poorly known because the impact of nonnative plants on higher trophic levels is one of the least-studied areas of invasion biology.
Overly abundant white-tailed deer preferentially browse and suppress native plant species, which favors the spread of invasive non-native plant species. Excessive browse simplifies vegetation structure, degrades wildlife habitat, and is an underappreciated cause of food web degradation and novel ecosystem creation. Simplified ecosystems lack the diverse mix of species capable of differential responses to disturbance, and lose the resilience needed to adapt to environmental change. Such ecosystems cannot reliably sustain wildlife or people.
We have no choice but to manage novel ecosystems for their conservation value and ecosystem services. We need to work at all scales and engage people. For example encourage private and public land owners to plant more native plant species and preserve backyard wildlife habitat. At landscape scales reduce human caused habitat degradation (e.g. altered nutrients and hydrologic regimes, pollution, deer browse and habitat fragmentation). On national and global scales fight for reduced emissions of greenhouse gases. We have a responsibility to care for and protect the earth and all of the life it supports.
Dr. Marilyn Jordan (firstname.lastname@example.org) retired in January as a Senior Conservation Scientist for The Nature Conservancy after working for TNC on Long Island since 1992. She grew up in Queens and got a BA in biology from Queens College (1966) and a Ph.D. in plant ecology from Rutgers University (1971). Her career experience includes air and soil pollution, microbial ecology, nutrient cycling in lands and waters, invasive plant science, fire ecology of the LI Pine Barrens, conservation planning, ecological monitoring, impact of deer on forests, atmospheric deposition and novel ecosystems.