I’m curious to discover answers to the following questions regarding three of Oregon’s top invasive species trouble-makers. I wonder if the answers are relevant to current discussion focused on solving Christmas tree root rot problems by introducing non-native trees.
- Why was the species introduced to our State in the first place?
- What impact does the species currently have on the eco-well-being or our State?
- Are these lessons relevant to Christmas tree industry introduction of non-native tree crops?
Himalayan (Armenian) Blackberry
The Himalayan Blackberry was originally introduced for fruit production. This plant, commonly called the Himalayan Blackberry, has been labeled with a number of botanical names. However, the preferred name is Rubus armeniacus Focke. Here’s why… In 1885 Luther Burbank introduced a cultivar of this species under the name “Himalaya Giant.” Later it was found to correspond to a blackberry in Germany. Only it really isn’t native to Germany, but is reported to have been introduced there in 1835. Its true origin seems to be: Armenia- thus, the botanical name, Rubus armeniacus Focke.
These plants quickly escaped from the gardens with the help of birds and animals. Himalayan blackberry seeds were dispersed, scarified, and “dropped” by our furry and feathered friends to take root in new places . This species is now well established along the west coast from British Columbia to California. The U.S. Department of Agriculture, Animal and Plant Health Inspection Service (APHIS) lists (Himalayan Blackberry) as a noxious weed. Rubus armeniacus Focke cannot be legally brought into the U.S. from foreign countries without a permit. The impacts of this noxious plant to Oregon are described by the Oregon Department of Agriculture:
Armenian blackberry is the most widespread and economically disruptive of all the noxious weeds in western Oregon. It aggressively displaces native plant species, dominates most riparian habitats, and has a significant economic impact on right-of-way maintenance, agriculture, park maintanance and forest production. It is a significant cost in riparian restoration projects and physically inhibits access to recreational activities. It reproduces at cane apices (tips) and by seeds, which are carried by birds and animals. This strategy allow it to expand enmass across a landscape or to jump great distances and create new infestations. Any control strategy can be considered short-lived unless projects are planned and funded for the long-term.
Nutria were first exported out of their native countries in South America to the United States in the 1880’s for fur trade. But is wasn’t until the 1930’s that Nutria were introduced to Oregon as a fur-trade commodity; with interest renewed in the 1950’s when nutria were promoted as breeding stock for the fur industry. The following video from OBP explains:
The damage being done to marshlands by nutria in Oregon is severe. Nutria feed on native plants that hold wetland soil together. Eating these plants, in addition to burrowing, causes the banks of lakes to collapse. Nutria can also damage flood control levees and weaken the foundations of roadbeds. In addition, nutria are often carriers of pathogens and parasites, posing a health risk to both people and other animals. Nutria have become a very serious problem to farmers, as well, because they eat vegetable crops such as lettuce, carrots, and sweet potatoes.
According to the Oregon Administrative Rules (635-056-0050), nutria are on the list of prohibited species, which outlaws the importation, possession, exchange, purchase, sale, and transportation of the animal. Shooting nutria is legal outside city limits, and they can be humanely euthanized by wildlife control officers.
Despite these efforts, nutria continue to be a problem. The extensive population and the gravity of the resulting damage illustrate the challenges and problems associated with introducing non-native species to an area.(OR Encylopedia).
The American bullfrog is considered invasive west of the Rockies in the US and in British Columbia. Native to the Eastern United States, why did they cross the Rockie Mountains? The Gold Rush is to blame. In the late 1800s, after gold miners had eaten the California Red-Legged frog (Rana dratonii) to near-extinction, bullfrogs were brought to California by both private and government efforts. Large numbers of bullfrogs were imported from the East to start bullfrog farms. When the demand for frog as a food staple subsided, many were set loose in the wild where they have wreaked havoc on native California frog populations ever since. In Oregon, bullfrog-farming was tried in the 1920s. Demand died out in the 1930s, the frogs were released into the wild. Oregon also experiences devastating impact to native frog species.
Just how do American Bullfrogs impact native frog populations? Bullfrogs adversely affect native aquatic animal populations in several ways. First, they have voracious appetites and feed on anything that fits in their mouths: eggs and offspring of native invertebrates; native vertebrates including fish, reptiles, amphibians, water birds, and even small mammals. Second, American Bullfrogs aggressively compete with those very same native vertebrates for limited food resources and habitat. According to a USDA study, “they may also have significant effects on aquatic vegetation. For example, tadpoles feeding on nitrogen-fixing algae an greatly influence aquatic habitat by reducing algal biomass, thereby decreasing primary productions and nutrient cycling.”American Bullfrog as Invasive Species Third, bullfrogs are known to transmit disease to native species. One serious pathogen they transmit is the chytrid fungus Batrachochytrium dendrobatidis. Finally, bullfrogs out produce reproductively, and overwhelm native populations.
Management of American Bullfrog populations is difficult at best. Trapping and hand-captures have limited affect due to the vast size of armies of bullfrogs. Draining of habitat or chemical treatment is extremely difficult because of adverse affects on native organisms. In Oregon, Bullfrogs are a controlled species. They can be legally harvested year-round; no angling license required. If bullfrogs are seen in the wild, the Oregon Department of Fish and Wildlife recommend, “Remove them to eat or kill them. One accepted method is stunning the frog with a sharp blow to the head, followed by decapitation. Make sure you have first identified the frog as a bullfrog; most native frogs are protected and cannot be removed from the wild or killed.”
A Future Threat?
That brings my back to wondering…
Will introducing the Turkish Fir to Oregon tree farms solve a problem in the short-run, but pose an ecological disaster in the future?
The culprit, according to CBS/KOIN news, is a waterborne fungus that damages the roots of the tree, causing it to die. The strain of Phytophthora fungus affecting the Christmas tree industry originated in North Carolina and came to Oregon from California. The solution to the problem: plant non-native trees, The Turkish Fir, because of its resistance to this fungus.
Is this a good idea… what do you think? Here is the link to the newscast: