NJAS Opinion: Winter, 1995

Exotics (nonnative plants or animals introduced into an environment) are a classic illustration of something being in the wrong place at the wrong time. We are familiar with the effects of exotic introductions in New Jersey. The chestnut blight in 1904 wiped out the American chestnut and changed the composition of our hardwood forests. Today chestnuts over twenty or twenty-five feet are virtually nonexistent, and the forest is less diverse.

Another invader was the gypsy moth. Imported in the last century with the forlorn hope of providing silk, the species escaped, causing havoc in the forest and reminding us once again that there is no substitute for choking these things off at the source, the proverbial ounce of prevention. If any good came from the gypsy moth, it was perhaps that it refocused attention on biological controls versus chemical controls Clearly, an ecologically principled approach based on biocontrol makes more long-term sense in controlling gypsy moth and other pests. The experience at Hawk Mountain was that not spraying the forest had the better long-term result than what was obtained at the adjacent sprayed forests (L. Goodrich, "Winter in June," Hawk Mountain News, No.74. Winter 1991, pp. 11 ff.). Our own experience at New Jersey Audubon's Scherman-Hoffman Sanctuary in Bernardsville was the same, during the infestations in the late sixties and in the seventies.

Biocontrol of exotic pests tends to be proactive, whereas chemical control is remedial or reactive in nature. An ecological strategy which checks the spread of a pest is better than a patchwork chemical elimination of the pest in limited areas. A recent special report of the National Audubon Society, "Exotic Pests: A Growing Threat to the Environment" (NAS, June 1994), details the threats to biodiversity and the economic damage caused by exotics and urges a proactive strategy. The report cites (among other pests) the case of purple loosestrife, now a national threat which has cost millions of dollars in damages in nineteen states. There is now hope for biological control of this species in the form of two leaf-eating beetles and a root-mining weevil.

Purple loosestrife is a threat in New Jersey for many reasons. It is a beautiful plant, attractive to insects, easily spread, and often sold in nurseries. Consequently, it has lots of help from people in invading wetlands, outcompeting native wetland plants. eliminating wetland biodiversity, destroying endangered species habitat, and lowering the value of wetland habitats. It forms dense clusters and is hard to eradicate, even with sprays permitted in wetlands. The time to develop a sensible, proactive, ecologically beneficial long-term strategy is now. We need to employ the control insects to prevent the spread of the plant, and we need to eliminate the sale and transport of the species. The state should consider declaring this species a noxious weed, as the state of Washington has done, and ban its sale. New Jersey is 19 percent wetlands by area, so we have a lot to lose in valuable habitat and species.

In particular the federally listed swamp pink (Helonias bullata) could be threatened by the spread of purple loose-strife. We don't want to jeopardize the substantial benefits obtained by the 1988 Freshwater Wetlands Protection Act because of the preventable spread of an exotic pest.

Another flash point for New Jersey is autumn olive, which in the past has been highly touted as a wildlife food by wildlife agencies and Audubon folks, and widely used for bank stabilization near bridges, highway culverts, and the like. We need to rethink the love affair with this plant. Yes, it does feed thirty species of birds in New Jersey, and mammals as well, but it has a downside. Autumn olive takes over and crowds out native shrubs which also bear fruit. The other native shrubs which it crowds out have maturation cycles timed to coincide with migratory bird passage and departure. Many of these are long-distance migrants dependent on fruit or the attendant native insects. These are not available from autumn olive. The time of ripening is key. The loss of native shrubs and trees to competition with this aggressive species has been noted by biologists and ecologists around the state in successional fields and even on the Delaware Bay-shore in salt marsh habitat. At least to some extent this species can be controlled manually in the proper management of fields. Again we need a strategy of long-term control which will prevent monocultures of this plant in fields and forest openings.

Richard Kane
Director of Conservation