4. La retransmisión de los videojuegos de carta
4.1.1 Análisis de situación: Septiembre 2018-Enero
collection areas are the major source for insects that are having a remarkable impact on the toadflax in these areas. Areas of initial releases are already showing dramatic reductions in density of this invasive weed and the insects are seeking out scattered, isolated infestations. The project also provides the base funding, matched by collaborators, for the western Washington Coordinator.
CHALLENGES OF INVASIVE PLANT
CONTROL IN WESTERN WASHINGTON
Invasive plant control in western Washington presents some interesting challenges to land managers. First, environ- mental conditions can vary widely between regions. For instance, dramatically different precipitation levels can pro- duce a range of conditions from desert-like grassland (e.g., Sequim) to temperate rainforest (e.g., Forks). The result of such differences in water availability can alter plant size and possibly growth patterns, particularly in high precipita- tion areas. Environmental conditions can also impact the biological control agents used to manage weed species. Most biocontrol agents are native to environments similar to eastern Washington habitats. Using these same agents in western Washington conditions and predicting similar results as other areas in North America may not be realistic and requires further exploration.Second, invasive species can have different and often stronger impacts on island plant communites compared to mainland communities. Special considerations are required with all aspects of invasive species management in such landscapes to minimize these impacts.
Third, diverse land use practices, including farm (large- scale to “hobby farms”), range, timber and intensely urban areas are widespread in western Washington. Challenges lie in effectively controlling invasive species while considering many landowners each with different land-use goals, weed problems and control strategies.
Fourth, although land managers have been implement- ing biological control as part of their integrated weed management programs, they rarely have the time, funds or expertise to use this tool to its full potential. WSU
Extension’s INWISP is assisting land managers in meeting these challenges by providing information, education, resources and the first organized biocontrol effort in west- ern Washington.
PROJECTS CRITICAL TO WESTERN
WASHINGTON
Two projects that are particularly important in western Washington are the control of purple loosestrife (Lythrum
salicaria L.) in tidal-influenced water and the potential new
biocontrol agent for Scotch broom (Cytisus scoparius (L.) Link). Galerucella calmariensis L. and G. pusilla (Duft.) (Coleoptera: Chrysomelidae), (purple-loosestrife foliage feeding beetles) have been greatly successful in many areas of the U.S., including much of Washington. However, the beetles rarely tolerate the regular inundation of water at purple loosestrife infestations that occur in areas influenced by tides. Examples of such areas include the Columbia River, rivers in Pacific and Grays Harbor Counties and the Snohomish Estuary. Two other biocontrol agents are available and appear to be tolerant of tidal-influenced envi- ronments: the flower-bud feeding weevil, Nanophyes mar-
moratus Goeze (Coleoptera: Brentidae), and the root-feed-
ing weevil, Hylobius transversovittatus Goeze (Coleoptera: Curculionidae). Nanophyes marmoratus is available for limited redistribution. Hylobius transversovittatus, however, is difficult to collect and large numbers are rarely obtained. In 2007, rearing of H. transversovittatus will begin in Washington in order to build large numbers of weevils for redistribution.
Scotch broom is a dominant invasive species in much of western Washington. In 2005, the accidentally introduced mite, Aceria genistae Nalepa (Acarina: Eriophyidae) (confirmation still required) was discovered in the Tacoma/ Seattle area. The mite appears to reduce seed production and biomass and when abundant may cause stem-dieback. WSU, King County Extension, USFS, Rocky Mountain Research Station and Oregon Department of Agriculture are collaborating to determine if the mite is host-specific to Scotch broom. Greenhouse and open-field tests were con- ducted in 2006 to test if the mite would attack native plants (e.g., species in the genera Lupinus, Thermopsis, and 140
Lathyrs) and crop species (e.g., soybeans). Tests will likely
continue in 2007. If Scotch broom is the only species attacked by the mite a request will be submitted to USDA APHIS for its approval as a biocontrol agent. Once approved, the mite will be available to distribute through- out Washington, Oregon and California.
CONCLUSION
INWISP’s implementation of integrated weed management tools assists in the effort to impact invasive plant species throughout Washington. Collaborations and funding through federal, state and local entities have been critical in allow- ing the successes we have had to date. These successes are evidenced through changes in landscapes towards more desirable conditions and reductions in the rate of landscape degradation from new invaders.
ABSTRACT
The ongoing arrival and invasion of Pacific Northwest ecosystems by non-native plant species is well-known amongst most botanists and land managers in the region. However, there are few comprehensive sources of information to describe the extent and impact of these invasions to policy-makers and the public. The objective of this study was to assess the ability of different types of information systematically collected across the region to describe the distribution and abundance of inva- sive species in the forests of the Pacific Northwest. Cover of the most abundant species was measured on 4,169 “standard” Forest Inventory and Analysis (FIA) sample points across Oregon and Washington from 2001–2005. Intensive measure- ments of all vascular plant species were collected on a systematic “intensive” subset of the standard plots, with 201 assessed to date. Plant cover was estimated on four 0.017 ha subplots at each plot location. Sixty-three percent of all intensive sample points had at least one non-native species recorded; proportions ranged from 100 percent in the dry Columbia Plateau and Basin and Range eco-regions to 33 percent in the North Cascades eco-region. The majority of the non-native species found were composites or graminoids, tended to be shade-intolerant, and were found in dry or recently-disturbed forest types. The most frequent invasive species found were Bromus tectorum L., Hypericum perforatum L., and Rubus laciniatus Willd., but several non-native species that are not considered invasive were equally common, including Mycelis muralis (L.) Dumort.,
Tragopogon dubius Scop., and Digitalis purpurea L. Although not common, some shade-tolerant species are locally impor-
tant, particularly Ilex aquifolium L. in lowland west-side forests. The average cover of non-native plants on plots in Oregon and Washington was 5.4 percent, suggesting that non-native plants cover 1,153,000 ha of forest land in the two states. Results indicate that non-native plants are already an important component of forests in the Pacific Northwest, even though many of the recently-arrived invasive species of concern have yet to make a substantial impact.
KEYWORDS: Forest Inventory and Analysis program, Oregon, Washington, non-native plants, forest.
1Andrew Gray is a Research Ecologist, Forest Inventory and Analysis Program, USDA Forest Service, PNW Research Station, 3200 SW Jefferson Way, Corvallis, OR 97331, 541-750-7252, [email protected].
INTRODUCTION
The invasion of non-native plants into new areas has had a large impact on natural and managed ecosystems. Invasive plants can directly affect the composition and function of ecosystems. They may also have a large economic impact, by changing or degrading land use, or through the costs of eradication efforts. These impacts are estimated to cost the U.S. economy at least $35 billion per year (Pimentel et al.
2005). Non-native plant invasions affect ecosystems and land use by competitively excluding desired species and altering disturbance regimes, and they are a primary cause of extinction of native species (D’Antonio and Vitousek 1992, Vitousek et al. 1996, Mooney and Hobbs 2000).
As a result of their impact on managed and natural ecosystems, the prevalence of non-native invasive plant species is a key element of many efforts that assess