2016 Focal AIS Species List

Transcription

1 2016 Focal AIS Species List The following list of focal AIS was developed in coordination with Portland State University, Oregon State University, Oregon Department of Fish and Wildlife, and Washington Department of Fish and Wildlife. It will be reviewed and adjusted annually. Pertinent AIS from this list will be included in survey efforts. Other AIS considered a local threat can be added to this minimal list. Type Common name Genus species Species Code New Zealand mudsnails Potamopyrgus antipodarum POAN Zebra mussels Dreissena polymorpha DRPO Quagga mussels Dreissena rostriformis bugensis DRRO Rusty Crayfish Orconectes rusticus ORRU Red Swamp Crayfish Procambarus clarkii PRCL Aquatic Ringed Crayfish Orconectes neglectus ORNE animals Bullfrog Rana catesbeiana RACO Northern Crayfish Orconectes virilis ORVI Nutria Myocaster coypus MYCO Asian Clam Corbicula flumina COFL Chinese mystery snail Cipangopaludina chinensis CICH Big Eared Radix Radix auricularia RAAU Aquatic plants Yellow Flag Iris Iris pseudacorus IRPS Hydrilla Hydrilla verticillata HYVE Nonnative Milfoils Myriophyllum species MYSP Yellow Floating Heart Nymphoides peltata NYPE Giant Salvinia Salvinia molesta SAMO Giant Reed Arundo donax ARDO Brazilian Elodea Egeria densa EGDE Didymo Didymosphenia geminata DIGE Flowering rush Butomus umbellatus BUUM Common reed Phragmites austalis PHAU Curly-leaf pondweed Potamogeton crispus POCR Purple Loosestrife Lythrum salicaria LYSA Garden Loosestrife Lysimachia vulgaris LYVU Water primrose Ludwigia spp. LU Terrestrial animals Feral Swine Sus scrofa SUSC Japanese Knotweed Fallopia japonica FAJA Hybrid Bohemian Polygonumx bohemicum POBO Knotweed Terrestrial Giant Knotweed Polygonum sachalinese POSA plants Giant Hogweed Heracleum mantegazzianum HEMA Old Man s Beard Clematis vitalba CLVI Garlic Mustard Alliaria petiolata ALPE Himalayan blackberry Rubus discolor RUDI 1

2 English Ivy Hedera helix HEHE Salt Cedar Tamarisk ramosissima TARA Orange hawkweed Hieracium aurantiacum HIAU Yellow archangel Lamiastrum galebdolon LAGA Invasive Aquatic Animals New Zealand mudsnails (Potamopyrgus antipodarum) These prolific snails often dominate the benthic habitat where they are found. Population densities of 100,000/m 2 are common in some rivers, comprising up to 95% of the macroinvertebrate biomass. They can out-compete and displace native macro-invertebrates that other species depend on for food. Disruption of the food chain has led to reduced growth rates and lower populations of fish species. The New Zealand mudsnail is often introduced through ship ballast water and aquaculture operations. Once introduced to a region, mudsnails can spread quickly by hitchhiking on the wading gear, boats, and trailers of fishermen, boaters, and watershed workers. The problem with hitchhiking is magnified by the mudsnail s small size and ability to survive extreme conditions. Surveyors and anglers are very likely vectors of this invader, carrying these small snails attached to their gear. Gear treatment is essential to avoid accidental transfer from infected waters to pristine waters. 0.7 mm 2

3 Zebra Mussel (Dreissena polymorpha) This tiny, fingernail sized, mussel is native to the Caspian Sea and has the ability to completely transform ecosystems. Annually, zebra mussels cause hundreds of million dollars worth of economic damage by clogging industrial and residential water-intake pipes. Loss of native mussel populations in the Great Lakes and Mississippi river is one the best documented impact of zebra mussels. Not only do they compete with them for food, but massive zebra mussel colonization of native mussels causes suffocation, shell deformity, starvation, and energetic stress leading to death. The mussel has an amazing capacity as a filter feeder to increase water clarity, and this can lead to greater blooms of algae. Toxic algae blooms poison the water, making people sick, and can kill small animals. 1.5 cm Anglers and surveyors can both be vectors for new infestations as they move from an infected stream to a healthy stream because the mussel is spread as the free-swimming veliger (juvenile) life stage. 3

4 Quagga Mussel (Dreissena bugensis) D. rostriformis bugensis is a bivalve mollusc originating from the estuaries of the Dnieper and Southern Bug rivers, both flowing into the Caspian Sea. In the mid-1980s, D. rostriformis bugensis was introduced into North America, presumably through discharge of ballast water from transoceanic ships. In 2007, a population was discovered in Lake Mead, a reservoir of the Colorado River. The quagga mussel is a sessile filter-feeder that is capable of reaching extremely high densities. Due to their ability to colonize hard surfaces, these mussels become a major fouling problem, clogging water-intake pipes and water filtration systems. They easily attach to canal locks, docks, buoys, hulls of the commercial and recreational vessels. 2 to 4 cm There are no native look-alikes, and their larger size shell has red to brown markings. 4

5 Large brown Spot on carapace Rusty Crayfish (Orconectes rusticus) This invasive crayfish are native to the Eastern United states. They have the potential to change food chain dynamics by out competing other detritivores and scavengers. Both pools and riffles provide this invader with habitat. Red Swamp Crayfish (Procambarus clarkia) This potential invader is native to the coastal plains of the Gulf Coast, from Mexico to Florida, and as far north as Illinois in the Mississippi River drainage. The red swamp aggressively competes with native crayfish and other aquatic species for habitat and forage. This species can act as a host for parasites and diseases. It is known by the black rectangular patches on the dorsal abdominal segments and the red knobs on the claws. Red knobs Black saddles or patches 5

6 Ringed Crayfish (Orconectes neglectus) This species is native to the central plains and Ozark regions, in the Mississippi River drainage. Introduced populations have been found in New York, as well as the John Day River and Umpqua River, in Oregon. This species prefers fast water and gravel/cobble streams. The impacts of this invader are unknown, but scientists expect that competition with native crayfish and other aquatic species for habitat and forage is possible. It can grow to 9 cm in length and is identified by the distinct black markings on its carapace, abdomen and claws. Even small individuals exhibit the identifying features (see photo at right). Blotches on segments Northern crayfish (Orconectes propinquus) This species is native to central Canada and U.S. Introduced to parts of the Southwest, Southeast and Mid-Atlantic regions. The Northern Crayfish is a short-lived species (~2 yrs) with a high reproductive rate. Competition and displacement of native crayfish has occurred where this species is introduced. It is identified by green claws with yellow tips and paired, tan / brown blotches on each abdominal segment. Burrowing can cause bank erosion, or damage irrigation structures. 6

7 DON T BE CONFUSED BY OUR NATIVE LOOK-A-LIKE! Signal Crayfish (Pacifastacus leniusculus) Our native crayfish is common to many streams in the Pacific Northwest. They can be identified by the smooth texture of their claws lacking noticeable bumps. The native crayfish s claws are also more robust (wider) than their invading cousins. Smooth claws, lacking bumps Chinese Mitten Crab (Eriocheir sinensis) Native to China and Korea along the Yellow Sea, this species is found throughout the San Fra ncisco Bay watershed and has migrated as far inland as the Sierra Nevada foothills of Ca lifornia. Range expansion along the West ast Co is expected. Th e Chinese mitten crab is a burrowing crab tha t has a catadromous lifecycle, breeding in bra ckish water, but living as adults in fresh wa ter. This means it spends the majority of its life in freshwater reaches of coastal watersheds, but reproduces and develops in brackish est uaries. 4 to 8 cm The width of its shell ranges in size from 4 to 8 cm. It is known for the furry mittens that cover all but the tips of their claws. 7

8 Chinese Mystery Snail (Cipangopaludina chinensis) Relatively widespread in waters that join the Great Lakes and the Northeastern Seaboard, this invader has been discovered living in the lower Columbia, Snake, Willamette, and Puget Sound drainages. The Chinese mystery snail is identified by their relatively large, globose (round) shells. Their operculum (the flap covering the opening used for feeding and excreting) has concentric markings. Cipangopaludina chinensis has a width that is often 75% of its length. Total length can reach 65 mm (~2.5 inches). An adult will usually have 6 to 7 complete whorls. The lighter coloration of juveniles transforms to an olive green, greenish brown, brown or reddish brown pigmentation as an adult. Four complete whorls in this snail Preferred habitat is silty bottoms, although the species can range well upstream of siltdominant stream reaches. C. chinensis uses its tongue-like radula to scrape and ingest organic and inorganic bottom material. Common diatoms are probably the most nutritious food it consumes. Its effects on native NW ecosystems have yet to be determined. Mystery snails can host parasites and diseases that are known to infect humans. Concentric rings visible on the operculum 8

9 Asian Clam Corbicula fluminea The Asian clam was first introduced to the United States from China in the 1920s, either as a food for Chinese immigrants or with the Giant Pacific Oyster importation. They were first established in California in 1938, then moved rapidly through irrigation canals and now continue to spread across the United States. These small freshwater mussels can be drawn into power plants along with coolant water and clog tubes and pipes, resulting in economic costs. The Asian clam will also compete with native clams and mussels for habitat and food, and change benthic substrates. In the Pacific Northwest, the species is likely to spread as long as it can endure the cold temperatures. Infested waters can be treated by hand (or with chemicals in closed environments like power plants). Navigation and dredging may also be used to prevent introductions in the first place. Lake Tahoe. This nutrient-poor habitat may serve as a good template for PNW streams and lakes. Scale is metric. The shell is 2.5 cm-wide. 9

10 Big Eared Radix Radix auricularia The ear-shaped aperture contains no operculum. The shell is thin and very inflated such that the last whorl comprises 90% of its volume. The color of the shell is yellow, beige or tan; and the shell are 4 5 whorls, with deep sutures between them. It has a rounded and broad spire that pinches in steeply at the apex. The mantle is pigmented with a line of dark spots along its edge. This species can grow to 35 mm in height and 25 mm in width as a full grown adult. However, most individuals in a population only grow to approximately half the maximum size. Found in freshwater lakes, ponds, and slowmoving rivers with mud bottoms. Radix auricularia can live on boulders or vegetation in low or high flow environments, and is capable of tolerating anoxic conditions, but tends to prefer very lentic waters in lakes, bogs or slow rivers where there is a silt substrate It has been found in environments with ph from Radix auricularia is native to Europe and Asia. Note the metric ruler for scale Likely a piggy-back invader with European vegetation, the big eared radix was brought into the Americas for use as an aquarium plant. These invaders are vectors for a diverse range of parasites, particularly trematodes, some of which may infect humans. Big Eared Radix distribution, 2015 Grazing on aquatic vegetation 10

11 Bullfrog (Rana catesbeiana) The American bullfrog has been transported around the world primarily with the intention of cheaply cultivating its large and meaty hind legs for human consumption. It is also of commercial interest to biological supply houses, fish bait suppliers, the pet trade, and pond landscapers. In North America in the early 20 th Century it was released outside of its natural range by wildlife agencies keen on introducing a new game species. It is extraordinarily prolific, prone to migration, and highly adaptable to new environments. It grows into a relatively large, voracious, and indiscriminate predator that can come to dominate the margins of lakes and ponds. It competes with native frogs. Tadpoles can have a significant impact upon benthic algae, and thus change aquatic community structure. Adults may be responsible for significant levels of predation on native frogs and other aquatic herpetofauna, such as snakes and turtles. The species also contributes to the spread of pathogens such as the chytrid fungus, Batrachochytrium dendrobatidis 11

12 Nutria (Myocastor coypus) This Asian relative of the beaver s burrows undermine the banks of rivers and dykes causing instability. Feeding on rhizomes and young shoots of marsh plants leads to plant community breakdown and can lead to erosion in coastal habitats. Nutria (aka: Coypu) feeding on sea oat rhizomes in Mississippi barrier islands have led to sand dune erosion in these important habitats. At high densities coypu are able to convert marshland to open water by feeding on plants. Habitat destruction caused by coypu threatens rare marshland species of bird, fish and invertebrates. 12

13 Invasive Fish Asian Carp No carp is native to the waters of the Pacific Northwest. Silver, bighead, and grass carp are large, fastgrowing, freshwater fish that can exceed 25 kg in weight. (Ctenopharyngodon idella) Grass (Hypophthalmichthys molitrix) Silver (Aristichthys nobilis) Bighead These species have been introduced around the world for aquaculture production, often becoming established in new regions. Silver and Big head carp tend to reside in surface water and leap out of the water (up to 2 meters high) when disturbed, causing boaters a serious safety risk. Silver and bighead carp are often found in high densities in the waterways they invade, becoming the dominant fish species in many areas. They have been confirmed in the Tillamook River basin in Oregon. The carp filter-feed on phytoplankton and zooplankton, and graze on aquatic vegetation. This behavior can put significant pressure on the base of the food chain and dramatically alter aquatic ecosystems. Competition with native fish species can diminish recreational fisheries. They can potentially carry and transmit new diseases to invaded ecosystems. Eyes of the silver and bighead carp are positioned beneath midline and their mouths are upturned. These characteristics make these two species unlike any native fish. The large scales of the grass carp are similar to suckers native to our waters, but the blunt mouth lacking fleshy lips distinguish the grass carp from our suckers. 13

14 Mosquitofish (Gambusia holbrooki) Adult mosquitofish are extremely aggressive and often attack other fish, shredding fins and sometimes killing them. They will eat larval fish, and compete with native fish of similar size and diet. As adults, they can reach 40 mm. Selective predation by mosquitofish has also been shown to alter zooplankton, insect and crustacean communities (McDowall, 1990). Mosquitofish are potential hosts of helminth parasites, which have been transmitted to native fishes. Commonly found in ponds and sloughs; rarely in swift water. Look for the distinct upturned mouth, relatively large scales, and black spot just forward of the anal fin. Black spot in front of Anal fin Similar in appearance, but Native Fish: Redside Shiners Our native shiners and dace have features similar to mosquitofish, but neither has an upturned mouth, nor a black spot just in front of the anal fin. Speckled Dace The shiners have visible scales like the mosquitofish; but unlike the invader, the margin of their dorsal fin isn t round. While juvenile dace can be as small as the mosquitofish, dace has very small scales making them easy to distinguish from the alien cousins. 14

15 Amur Goby (Rhinogobius brunneus) The invasion of the goby is believed to be the result of ballast water release from ships. It has been confirmed in the East Fork Lewis River, WA; the Sandy River and the Ramsey Wetland, OR. Impacts of this invader are unknown. Like their native cousins, the sculpin, gobies are suspected of preying on salmonid eggs, but no one has directly observed this activity. Like sculpins, gobies are benthic fish, occupying the spaces between cobbles and boulders. Native sculpins can be distinguished from this alien by several features. The scales of sculpins are too small to distinguish, their anterior dorsal fin is not triangular, and their pelvic fins are not fused. The goby s scales are easily visible, it has a sail-like anterior dorsal fin, and their pelvic fins are fused into a single structure that functions like a suction cup. The Amur goby also has two red or dark lines running from the snout to each eye and a bulb-like growth on the gill cover. If you suspect this invader is present, in addition to communicating with Forest Service personnel, please contact: Paul Heimowitz, USFWS paul_heimowitz@fws.gov Native Look-a-likes: sculpins lack obvious scales and have a curved margin on their 1 st dorsal fin Torrent Sculpin Amur goby Triangular 1 st dorsal fin Visible scales Mottled sculpin 15

16 Invasive Aquatic Plants Hydrilla (Hydrilla verticillata) An escapee from an aquarium, hydrilla remains a popular plant to use in fish tanks, but can displace native aquatic plants due to its aggressive growth. The root system includes tubers of a half inch or less in size, and the plant colonizes slack water habitats. Leaves are attached to the stem in a whorl pattern of four to eight leaves per whorl. No native aquatic plants have this pattern of leaf attachment. 16

17 Yellow Flag Iris Iris pseudacorus This aquatic plant modifies its environment by forming dense horizontal root mats that trap and retain sediment. As sediment accumulates, the wetland or slack water channel fills in, reducing aquatic habitat and altering wetland hydrology. Looking like a fan, multiple leaves emerge from the same point along a submerged stem (see photo). The flowers can stand nearly 5 ft above the water surface. Each leaf is sword-like in appearance, and each has a thickened central vein from the base to the tip leaf, giving the leaf rigidity. It produces a yellow flower, the only all-yellow iris in the Northwest. Yellow flag iris out-competes and displaces native aquatic plants. Didymo Didymosphenia geminata Known as rock snot, Didymo can form large mats in rivers and streams. These mats can impact plant, invertebrate, and fish communities through displacement and alteration of aquatic habitat. It often looks like toilet paper trailing from rocks and aquatic plants in streams. Although it appears slimy, the texture is similar to damp wool. Rock snot is mainly found in warm, pristine waters with abundant sunlight, low nutrients, and high oxygen levels. It has the potential to cover gravels and cobbles used as salmon spawning beds and clog the spaces insects use as habitat. 17

18 Parrot Feather Watermilfoil (Myriophyllum aquaticum) M. aquaticum (parrot-feather) is an invasive aquatic plant native to the waters of South America. It occurs as a submerged/emergent aquatic weed characteristic of sub-tropical to warm-temperate regions, but now found as far north as the UK. Its occureence has been confirmed in at least 33 countries, but native to perhaps 6 of these. There are various ways in which aquatic weeds such as M. aquaticum can have detrimental impacts. These include interference with flow of irrigation water, river transport, hydro-electric power production, fisheries, recreation, and increased risk of health hazards. 18

19 Eurasian Watermilfoil (Myriophyllum spicatum) This invader, also known as spiked watermilfoil, is an invasive submerged aquatic weed characteristic of temperate regions. It is now found as far north as the UK and Canada, and as far south as South Africa. It is known to occur in at least 57 countries, probably native to all those Eurasian countries in which it occurs. M. spicatum is an invasive in the USA and Canada. It is a particular problem of streams, rivers and small water bodies where it primarily impedes flow and causes a range of associated environmental problems, such as water deoxygenation. Long-distance spread via the aquarium/garden trade has made human consumers a major vector. Once introduced to a new region it spreads rapidly, primarily by vegetative stem fragmentation, and via transport while attached to boats, athough seed production also occurs. 19

20 Variable-leaf milfoil (Myriophyllum heterophyllum) This common aquarium plant is considered invasive throughout the Pacific Northwest, because of its tendency for uncontrolled growth and subsequent formation of dense mats, from the bottom of a water body to the water s surface. These mats prevent water flow, reduce sunlight, reduce oxygen availability, and impede swimming, boating and fishing. As its name implies and the images demonstrate, the shape of the leaf has many forms, making it difficult for the casual observer to identify. Variable-leaf milfoil is banned from sale in Washington state. M. heterophyllum forms dense stands in water bodies, which have negative effects on boating, swimming and aesthetics. Note hair-like leaves in a whorl around a stem. Note flat leaves in a whorl around a stem. 20

21 Brazilian Elodea (Egeria densa) E. densa is highly desired in aquaria and small ponds, but has become a serious invasive species in larger bodies of fresh water, where dense mats reduce recreational options and crowd out native species as well as altering the hydrology. The principal means of establishment is considered to be disposal of aquaria contents into local waterways. Spread is by vegetative means since many introduced populations comprise only male plants. When dense mats of E. densa have formed, native species are displaced, oxygen may be depleted and the character of stream and lakes may be changed. The effects on the environment may be substantial, affecting the hydrology also. When dense mats of E. densa have formed, native species are displaced, oxygen may be depleted and the character of stream and lakes may be changed. The effects on the environment may be substantial, affecting the hydrology as well. 21

22 Curly-leaf pondweed (Potamogeton crispus) P. crispus is a submersed plant that is nonnative and invasive in temperate areas of North America. The species is a cold weather strategist, which allows it to establish early in the growing season. Unlike most aquatic plants, curly-leaf typically dies back by early summer and lies dormant until temperatures decrease. It tends to form thick mats, decreasing the light available to other species. The summer die-back and decay causes nutrient release that stimulates algal blooms and depleted dissolved oxygen. This species is particularly hard to control due to its prolific production of turions, a bud produced by dying leaves that detaches and remains dormant until the following spring. Curly-leaf pondweed can present significant navigational difficulties to recreational users by fouling outboard motors. They degrade the recreational value of waterbodies they invade. 22

23 Water Primrose (Ludwigia spp.) This New World native is a productive perennial, emerging from shallow water. It has become one of the most damaging invasive plants in France. Recent introductions beyond its native range in the USA has caused severe problems. Water primrose can transform ecosystems both physically and chemically. It can sometimes be found growing in impenetrable mats; under these conditions, Shown: Large-flower water primrose L. grandiflora can displace native flora and interfere with flood control and drainage systems, clog waterways and impact navigation and recreation. The plant also has allelopathic activity that can lead to dissolved oxygen crashes and the accumulation of sulphide and phosphate in the water. These not insubstantial and year-round effects on water quality can cause dystrophic crises and intoxicated ecosystems. L. hexapetala is currently typed as a subspecies of L. grandiflora. Shown: Floating water primrose Shown: Large-flower water primrose 23

24 Flowering rush (Butomus umbellatus) Flowering rush is a perennial aquatic herb that emerges each spring from winter-hardy rhizomes. Emergent leaves are stiff, narrow, sedge-like (3-edged or triangular in crosssection) and up to 3 feet above the water surface. In deep water, the plant can be entirely submerged. Submerged plants have limp leaves and do not flower. This pioneer can form dense stands which may crowd out native plants and in turn harm fish and wildlife. Plants spread by underground rhizomes, forming dense stands and crowding out native species. Reproduction from seed is uncommon. Small populations can be hand-dug, but extreme care must be taken to remove all root fragments. When the root system is disturbed, small reproductive structures can break off and spread to other areas. All plant parts should be composted away from aquatic environments. 24

25 Purple Loosestrife Lythrum salicaria Native to Eurasia, this is an erect perennial herb in the loosestrife family (Lythraceae), with a square, woody stem and opposite or whorled leaves. Leaves are lance-shaped, stalkless, and heart-shaped or rounded at the base. It spreads through the vast number of seeds dispersed by wind and water, and vegetatively through underground stems at a rate of about one foot per year. In our wetlands and riparian corridors, purple loosestrife can outcompete and replace native grasses, sedges, and other flowering plants that provide a higher quality source of nutrition for wildlife. Sadly, many State agencies, wildlife organizations, and commercial nurseries do not yet think the plant is a problem and continue its use. 25

26 Garden Loosestrife Lysimachia vulgaris Native to Eurasia garden loosestrife was intentionally introduced to N. America, this is an erect herbaceous perennial plant in the primrose family (Primulaceae) that can grow to more than 3 ft.-tall. Dense stands are the result of underground stems producing new shoots from the same plant. Leaf growth has a variable pattern; emerging along the stem sometimes opposite or paired, whorled about the stem. Some leaves are narrow, others ovate, but all have pointed tips. Leaves are usually stalkless and rounded at the base. Flowering occurs from June through August, producing showy, yellow florets, often with an orange to red center. Preferring damp soil, garden loosestrife is an effective pioneer in many wet soil types. In our wetlands and riparian corridors, garden loosestrife can outcompete and replace native grasses, sedges, and other flowering plants that provide a higher quality source of nutrition for wildlife. This plant is a potential problem inand continue its use. It spreads through the vast number of seeds dispersed by wind and water, and vegetatively through underground stems (i.e., stolons) at a rate of about one foot per year. 26

27 Giant Salvinia (Salvinia molesta) Annual or perennial, Giant salvinia is free floating, with microspores and megaspores produced on the same plant. Fronds of the fern are up to 30 cm long, 5 cm wide, mat-forming, mat to 2.5 cm thick (or much thicker, depending on local conditions such as water current, waves, etc.); roots absent; stems irregularly branched, hairy. Giant salvinia can form dense mats that block sunlight and reduce oxygen levels, radically altering ecosystem function. Under conditions of nutrient enrichment, it shades submersed species, impacts fisheries, and negatively affects recreation and transportation. It is reported as a nuisance even in its native range. The native range of Giant salvinia includes Trinidad, Guyana, Brazil, Paraguay and Argentina, although some sources report a natural broader range throughout Central and South America. 27

28 Yellow floating-heart (Nymphoides peltata) A bottom-rooted perennial plant with floating leaves, which can reproduce prolifically through both vegetative and sexual means. Often growing in dense mats, yellow floating-heart displaces native species, reducing biodiversity, decreasing water quality, impeding recreational activities, and diminishing aesthetic value. It is difficult to control due to its ability to form a new plant from rhizomes, stolons, separated leaves, or seeds. Birds may be dispersal vectors, however, the water garden industry may play a larger role in its spread. 28

29 Kudzu (Pueraria lobata) This high climbing vine often completely covers trees, shrubs and man-made structure forming kudzu sculptures. The leaves are alternate, six to eight inches long, have fuzzy leaflets three to four inches long, oval, lobed or nearly heart shaped. Flowers are large hanging clusters of pea-like, purple to red color, with a grape-like smell and appearing in midsummer. Kudzu kills or degrades native and desirable plants by smothering them under a solid blanket of leaves, by girdling woody stems and tree trunks, and by the sheer force of its weight breaking branches or uprooting entire trees and shrubs. Kudzu s leaflets of three 29

30 Giant Reed (Arundo donax) Originally introduced for erosion control, Giant reed crowds out native plants species; reduces wildlife habitat; contributes to higher fire frequency and intensity; and modifies river hydrology. Giant reed is thought to be native to eastern Asia. This aggressive invader forms dense, monotypic stands up to 25 ft. tall. It uses more water than native plants, lowering groundwater levels. A. donax has substantial economic value. It is a valuable and very fast-growing crop that is being promoted for the production of fuel, fibres and pulp, and is also widely used as an ornamental. This means that further introductions are likely and the balance between exploitation and threat as an invasive plant requires careful consideration. 30

31 Common Reed Phragmites australis P. australis is a robust erect perennial grass, that invades aquatic or riparian habitats. It grows to 4 m high (occasionally 6 m), creates dense clumps, and possesses an extensive rhizome system. Stems are rigid, with many nodes; and the stems are hollow between the nodes. Leaves alternate, up to 70 cm long, tapering to a spiny point. Flowering head has a feathery appearance, sometimes drooping, cm long, often tan-brown to purplish. Phragmites reeds are major aquatic weeds, and also act as weeds in other non-crop systems, for example, in forests and along railways. They can affect a wide range of habitats, invading aquatic and riparian areas. They can even establish in terrestrial habitats, provided soils remain moist for extended periods. 31

32 Invasive Terrestrial Animals Feral Swine (Sus scrofa) S. scrofa occupies the largest geographical range of all species in the pig family. It originally occurred in Europe, Asia, North Africa, and the Malay Archipelago. Included in this native range were a number of island populations, including the British Isles, Corsica, Sardinia, Japan, Sri Lanka, the Ryukyu Islands, Taiwan, Hainan, Sumatra, Java, and smaller islands of the East Indies. While there are many varieties of domesticated swine, they are all member of the same species. Sus scrofa was later introduced throughout the world as a domesticated animal by humans. Currently, S. scrofa can be found in all continents and a wide range of environments from boggy marshes to mountainous terrain. Rooting is common sign used to identify feral pig activity. These areas can be large, covering an entire field. In soft soils, rooting can be three feet deep. They will also form wallows in wetlands to moderate summer heat. In the process of foraging for roots and excavating wallows, feral swine destroy the existing vegetation. Boars are aggressive in their territorial defense. A riparian zone cooling wallow 32

33 Invasive Terrestrial Plants Knotweeds Japanese (Fallopia japonica) Giant (Polygonum sachalinense) Cultivated (Polygonum polystachyum) The only effective known treatment is a combination of mechanical removal and chemical treatment as new shoots emerge. Prevention and early detection is the key. Three species have invaded the riparian areas of our streams. Native to Asia and Japan, these members of the buckwheat family have been planted by homeowners as shrubs that resemble bamboos. All three species quickly establish dense stands once they have been introduced. Note the gentle bend at each node Knotweeds can grow to over 12 ft high and outcompete all other plants by blocking nearly all sunshine and through the release of toxins into the soil that prevents the growth of other plants. These invaders are extremely difficult to eradicate because new shoots can be produced from each node along their stalks and their underground stems (rhizomes). Shredding a stand actually causes the infestation to spread as their living stalks nodes are scattered; and after a three year period during which black plastic covered a harvested stand, the rhizomes were still alive and sending up shoots. In addition to the height and the thick growth pattern, knotweeds have several distinguishing features. The stalks have a distinct pattern of a very gentle zigzag. At each node, the stem section above is at a distinct angle to the section below the node. The leaves are always broad and taper to a point. Note pointed end to leaf 33

34 English Ivy (Hedera helix) Ivy was introduced as a landscaping ground cover, but it has escaped and become widespread in the Northwest. It is very adaptable to either wet or dry soils. Seeds of this toxic plant are readily dispersed by birds. Once established it spreads vegetatively on the forest floor and then climbs trees up to the canopy where it flowers and fruits freely. Ivy infestations can form dense ground cover and attach to trees, sending shoots high into the canopy. Eradication of an infested area has proved very difficult. Himalayan Blackberry (aka: Armenian blackberry) (Rubus discolor) This invader can rapidly spread, colonizing newly disturbed sites as well as invading undisturbed lands. A hybrid cultivated for its berries, it is another garden escapee that is very difficult to eradicate without the use of repeated chemical treatments. The native blackberry trails its stems across the forest floor and has often caused hikers to trip. Himalayan grows as thickets which sane folk avoid entering due to its thorny stems and leaves. The native blackberry produces small berries and tends to have three leaflets, whereas Himalayan blackberry produces very large berries and each leaf has five leaflets, all heavily armed with thorns. 34

35 Salt Cedar (Tamarisk) (Tamarisk ramosissima) This native of Asia possesses numerous inherent physiological characteristics that make it adapted to natural or modified riparian ecosystems and make it appear to be more aggressive and better adapted to the invaded native ecosystems of western North America than are the native plant communities. It scalelike leaves are similar to our native cedars, but it is a flowering plant, producing pink to white blossoms. T. ramosissima has an extremely high reproduction rate, the ability to produce seeds over a very long time period (throughout the growing season), very efficient means of seed dispersal, the ability to reproduce vegetatively as well as by seed, and mechanisms for rapid seed germination and seedling establishment. 35

36 Giant Hogweed (Heracleum mantegazzianum) An ornamental from its native area in Russia and the Caucasus Mountains, giant hogweed is still available as an ornamental plant., Giant hogweed also occurs as a contaminant of international trade, and is therefore likely to spread further. It is an undesirable invader due to its large size, prolific seed production and vigorous growth that causes major changes in vegetation, obstruction of access to river banks, soil erosion, and serious skin sensitivity occurring on skin contact. 36

37 Garlic Mustard (Alliaria petiolata) Garlic mustard has spread throughout much of the north-eastern and mid-western USA and Canada after its introduction from Eurasia. The species invades forested communities and edge habitats. The plant has no known natural enemies in North America, has the capacity to adapt to variable climates and soils, is self- fertile, maintains a seed-bank, and is quite difficult to eradicate once established. 37

38 Old Man s Beard (aka: evergreen clematis) (Clematis vitalba) Native to Northern Europe, C. vitalba produces many seeds that are wind dispersed, and it is a strong colonizer of disturbed ground. It is a fastgrowing vine with the ability to climb up and bring down tall trees and reduce standing forests to impenetrable low-growing infestations. It has the ability to expand its range in Europe, North America, Australia and New Zealand, and to be further introduced in as yet, pristine environments due to its use as an ornamental plant. An infestation of Old man s beard can reduce the forest structure, and change the recruitment patterns in forests. It grows so strongly in forest margins and light gaps that vines can form a dense, light-absorbing canopy that suppresses all vegetation beneath it and can be so vigorous that the weight of foliage and stems breaks the supporting trees. MC Sheehan,