Native plants and animals face a number of widespread threats, including global warming, loss of habitat, overexploitation, pollutants, and invasive species. Each of these can cause a decline in overall ecosystem health and a loss of biodiversity. Some of these threats create impacts on such a large scale that it is hard for local efforts to produce observable benefits.
Yet, the overwhelming presence of invasive species has become obvious in many regions, and conservation organizations are increasingly working towards counteracting their spread. To be effective, some invasive species need to be addressed on a broad scale, so local efforts should build off regional or national efforts. On the other hand, some ecosystems can also be improved on a local level, so management efforts can be effective with the proper approaches and planning.
When undertaking local projects to counteract the spread of invasive species, please keep the following principles in mind:
1. An invasive species presence is a symptom rather than the cause of ecological imbalance. Current thinking is that invasive species do not drive declines in habitat, but rather opportunistically move in to partially stabilize stressed environments.
2. Removal of invasive species is not an environmental goal itself. Resources should be managed for biodiversity (or other ecological value) and not just against invasive species.
3. A written management plan should guide any invasive species control work. The plan should include a brief listing of the overall conservation goals, ecological threats (invasive species and others), priority locations, priority species, removal methods, cleanup, replanting, restoration, and administrative procedures. The plan also serves as a communication/decision tool for property owners and other stakeholders.
4. Restoration is usually a necessary part of invasive species management. When invasive plants are removed, replanting with native species is important to prevent new invasions.
5. Priorities for invasive species control should be determined locally. Priorities often are based on prevalence and impact of the species present. Generic lists of invasive species usually do not reflect local conditions.
6. Side effects of removal/control deserve consideration. For example, removal of invasive trees can change the woodland ecology for many years and might enable additional invasive species to become established. Use of herbicides might damage nearby, desirable plant species. Biological controls sometimes result in unintended consequences.
7. The methods used for removing invasive species are critical. Soil disturbance tends to promote spreading of invasive plants and germination of invasive plant seeds.
8. A priority is to prevent invasive species from encroaching on pristine areas. More progress can be achieved in locations with minor infestation than in locations that are already overrun.
9. Eradication of an invasive species from a location takes time. Rhizomes and other plant material can re-sprout, and seeds often remain viable in the soil for many years.
10. Steps taken to prevent future infestations can improve long-term results. Landscapers and neighbors should be encouraged to stop planting invasive species and to remove existing ones. Control of deer populations allows native plant species to recover and thrive.