Nile Valley North of Nubia (Delta), Nile Valley North of Nubia (Fayium), Nile Valley North of Nubia, Nubia.
Perennial.
Botanical description: This description covers characteristics that may be relevant to fire ecology and is not meant for identification. Keys for identification are available (e.g., [112,113,187,268,298]).
Aboveground: Reed canarygrass is a rhizomatous perennial grass that grows from 2 to 7 feet (0.6-2 m) tall [64,83,87,112,113,194,241,268,298]. It has broad, flat leaves that are 5 to 25 mm wide [64,222,268,298] and a hollow stem [238]. Leaves are typically green but may be variegated [58,112,113,290,298]. Reed canarygrass' spikelets are 3-flowered [298] and occur on a narrow panicle 2 to 12 inches (5-30 cm) long [64,83,112,187,194,222,268]. The fruit is 1.5 [111] to 4 mm long [64,289] and from 0.7 to 1.5 mm wide [64,111]. Because no morphological characteristics clearly distinguish the native reed canarygrass from the nonnative types, discrimination between the two types is difficult ([58,205], review by [119]).
Belowground: Reed canarygrass spreads by creeping rhizomes [99,112,131,143,194,214,222]. Its rhizomes are stout [131], long [238], and scaly [87]. New rhizomes originate almost entirely below the soil surface from buds at the nodes of other rhizomes [62] but may occasionally develop at the base of the aboveground shoots from buds in the axils of the leaves [63]. Under experimental conditions, reed canarygrass rhizomes were 1.6 [62,63] to about 4 inches [219] (4.1-10 cm) long and were located in the upper 1 to 5 inches (3-13 cm) of soil [219]. In Idaho, wild populations of reed canarygrass form dense, rhizomatous root mats in the upper few inches of the soil [94]. Rhizomes grown in wet soils were longer (maximum length 4 inches) than those grown in dry loam garden soils (maximum length 2.5 inches), and rhizomes grown in sand averaged 1 inch (3 cm) long. In an experimental garden, 1 square meter of loam contained about 383 feet (117 m) of rhizomes [219]. In monotypic stands of reed canarygrass in the Czech Republic, all rhizomes and over half of the root system occurred in the upper 8 inches (20 cm) of soil [154]. Under experimental conditions, reed canarygrass rhizomes grow out from beneath the grass clumps and form culms [62,219]. Roots and rhizomes may form an almost impenetrable sod [62,219].
Stand structure: Reed canarygrass forms large clumps [250] that may be as wide as 3 feet (1 m) across [283]. On many sites reed canarygrass forms dense monotypic stands [7,15,94,148,184,195,240,260,271,301]. Reed canarygrass may grow as a sward (i.e., lawn-like) or occasionally create tussocks [108,299].
Genetic Variability: Differences in reed canarygrass production rates [169], photosynthetic characteristics [27], forage yields [252], seedling survival rates [218], growth response to vegetation density [217], and capacity to produce a new stand through vegetative regeneration [36] have been attributed to its high genetic variability. Genetic variation may influence reed canarygrass' invasive potential [27] and may have facilitated its spread in North America [169].
Reed canarygrass occurs throughout most of the continental United States with the exception of Texas, Louisiana, Mississippi, Florida, Georgia, and South Carolina. It occurs north throughout Canada and into Alaska [282] and as far south as northern Mexico [298]. Allard and Evans [3] indicated that reed canarygrass' North American distribution is likely a reflection of its need for long days for flowering (see Seasonal Development). Reed canarygrass is common in the northern half of the United States and southern third of Canada [76], especially in the Pacific Northwest [57,83,184,257,283], the northern Rocky Mountains [252], the north-central states [251,252,257,283], and the Great Lakes states [245,283]. Plants Database provides a map of reed canarygrass' North American distribution, excluding Mexico.
Reed canarygrass is a circumboreal species and occurs in the temperate regions of 5 continents [76,83,131,257]. It is generally considered native to temperate parts of Europe, Asia [2,119,187,301,306], and North America [14,50,83,87,111,113,187,192,298], and may be native to Pakistan and Kashmir [2]. It has been introduced to parts of the southern hemisphere [87], specifically New Zealand, Australia [131], and South America [298]. Cultivation of reed canarygrass began as early as 1749 in Sweden, and it has been cultivated extensively throughout Europe; cultivation in North America was first reported in New England in the 1930s (using ribbon grass) [4]. Reed canarygrass has been widely cultivated in North America from introduced European cultivars [76,195,246,250], making its pre-agricultural distribution uncertain. Galatowitsch and others [76] suggest that reed canarygrass is a species whose origin cannot be positively determined.
Native status in North America: There is some confusion as to the native status of reed canarygrass in North America. Most North American floras treat reed canarygrass as a native species [14,50,83,87,111,113,187,192,298]. Publications from the inland Northwest [94,97,205], New Mexico [220], the Great Plains [59], the Great Lakes area [53,128,130,195,246], Pennsylvania [309], Ontario [58], and Manitoba [213] consider reed canarygrass native in their area. However, a few publications regard reed canarygrass as a nonnative in the Pacific Northwest [185,274,301].
Evidence that reed canarygrass is native to at least some locations in North America includes a study of historical documents and herbaria records of reed canarygrass collected in the inland northwestern United States prior to widespread European settlement in that area [205]. Similarly, a study of herbaria records in Quebec found a few specimens of reed canarygrass collected from remote locations during the 19th century, supporting the contention that it is native there [170].
Invasive populations of reed canarygrass occur in many areas throughout its range, particularly in the northwestern [35,66,188,234,248] and north-central [15,145,196,240] United States, and increasingly in eastern North America [170]. It is generally thought that invasive populations are comprised of either nonnative strains or hybrids between nonnative and native strains [58,196,205,246,271]. Researchers in Ontario [58] observed noninvasive populations of reed canarygrass in “native habitats” along the shores of the northern Great Lakes and the upper Ottawa and French rivers, as well as invasive populations in anthropogenically altered landscapes. They speculated that noninvasive populations were native, while invasive populations were the progeny of European cultivars [58]. A genetic analysis of populations in Europe and North America (Vermont and New Hampshire) indicates that invasive populations of reed canarygrass in North America are comprised of genotypes resulting from multiple introductions of European cultivars and subsequent interbreeding of these populations [169]. The long history of repeated introductions of reed canarygrass into North America has resulted in substantially higher within-population genetic diversity in its introduced range as compared with its native range, allowing for rapid selection of novel genotypes and increased invasive potential [169]. See Genetic variability for a discussion of variable traits that may influence the invasiveness of reed canarygrass.
Native populations of reed canarygrass that have not been exposed to gene flow from nonnative strains may no longer occur in North America. Additionally, morphological variability makes it difficult, if not impossible, to distinguish between native and nonnative populations [205]. Decisions to control populations of reed canarygrass may be based on its impacts in a given area rather than its ambiguous native status.
Because reed canarygrass' native status in North America is unclear, its relationship to historic FIRE REGIMES in plant communities where it occurs is unknown. Reed canarygrass typically occurs in wetlands and riparian areas. Fire is important to the maintenance and development of some wetland communities [77,233,297]. Wetland plant communities have varying moisture regimes and fuel characteristics, so fires in these ecosystems vary in frequency and intensity; some, such as marshes, may burn frequently; others, such as forested wetlands, seldom burn [183]. In eastern coastal marshes, grasses in general burn more readily and usually support much more intense and continuous fires than forb- or sedge-dominated plant communities [291]. Of special interest are peatlands where reed canarygrass occurs. Peatlands in Wisconsin have been known to burn in excess of 2 years [51].
Few studies have investigated the behavior, properties, and influence of wildfire in riparian areas. Riparian forests generally have more available moisture and may differ in understory vegetation, fuel loads, and fuel moisture from adjacent uplands. In these communities, especially in moist forest types, fire typically has longer return intervals and is less severe than in adjacent uplands [61].
Reed canarygrass may persist with frequent fire. In Wisconsin, reed canarygrass was a codominant species in a wet-mesic prairie that had been burned for 30 years on at least a biennial basis. While it is unclear when reed canarygrass established on this site, its relative dominance in the plant community suggests its invasion was not recent [42].
Reed canarygrass may establish on sites where fire is reintroduced after having been excluded for years. In northern Illinois, reed canarygrass established in mesic prairies when fire was reintroduced after being excluded for at least 22 years (1978-1998). Reed canarygrass was not recorded on these sites in 1976 or 1998. However, in 2003, 5 years after fire was reintroduced, reed canarygrass occurred in 10% of plots in dry-mesic gravel prairie and in 20% of plots in mesic gravel prairie [24]. The authors did not indicate whether reed canarygrass propagules came from residual or off-site sources.
Because reed canarygrass is a cool-season grass, spring fires that prevent its flowering may limit its spread (see Plant response to fire).
See the Fire Regime Table for further information on FIRE REGIMES of vegetation communities in which reed canarygrass may occur. Find further fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find FIRE REGIMES".
Reed canarygrass establishes rapidly after fire on sites where it occurs in the prefire plant community (see Plant response to fire), suggesting that it is adapted to survive and regenerate after fire. Few studies describe fire characteristics or indicate whether postfire establishment of reed canarygrass is from sprouting or seed germination.
Postfire sprouting from surviving rhizomes and/or root crowns may allow reed canarygrass to regain prefire density and biomass shortly after fire. Reed canarygrass rhizomes likely survive fire under most conditions, with the exception of those exposed to severe ground fires that may occur in organic soils (see IMMEDIATE FIRE EFFECT ON PLANT). In an Oregon wetland, reed canarygrass tiller density increased within 2 years following prescribed fire; however, no information was given on fire frequency, severity, or substrate characteristics associated with this study [279]. In Minnesota, reed canarygrass biomass was similar in burned and unburned plots (200-300 g/m²) 12 weeks after a "high-intensity" prescribed fire [1].
Studies from Minnesota [1] and Tennessee [69] indicate that reed canarygrass establishes from residual seed banks after fire. It may also establish from off-site seed sources (see Seed dispersal). Researchers [1,240] have speculated that fire creates optimal germination conditions for reed canarygrass by improving light availability. At the time of this writing (2010), no information was available on characteristics that enable reed canarygrass seed to survive fire.
Although several studies report on the use of fire to manage reed canarygrass, as of this writing (2010), little has been reported on its fuel characteristics. Wetland fires may be difficult to conduct in monotypic stands of reed canarygrass because it remains green into the fall (reviews by [119,277]). High water levels may also limit burning in wetlands ([97], review by [119]). Wade and others [291] described fuel characteristics for coastal marshes in the eastern United States although they do not address reed canarygrass specifically. In general, these ecosystems support abundant fine fuels and large quantities of herbaceous vegetation that is often "highly" flammable [291].
As mature reed canarygrass plants senesce late in the season, litter accumulates and forms thick, impenetrable mats [119,294]. Fire may be used to reduce this litter ([69,305], review by [277]), even when standing reed canarygrass is green. In near-monocultures of reed canarygrass (>80% relative cover) in an experimental field in Wisconsin, litter comprised more than 80% of total biomass in unburned plots in May but less than half of total biomass in unburned plots in August. Fire behavior was more variable on August-burned plots in this sutdy than on May-burned plots. The year after a single burn, productivity did not differ significantly between May-burned, August-burned, and unburned plots. However, the year after a second burn, productivity was greatest on spring-burned plots, less on summer-burned plots, and least on unburned plots (P<0.05) [129]. In a dense stand of reed canarygrass in Minnesota, researchers did not get a "good burn" during a June prescribed fire, which they attributed to the high moisture content of the litter [240].
Reed canarygrass may produce wind-borne embers when stands are burned (Eggers personal communication 1997 cited in [249]).
Reported germination rates in reed canarygrass are variable [44,92,117,173,178,180,289]. Germination studies, primarily for agricultural purposes, have reported from 3% [44,117,289] to 93% germination [44,92,173,178,180,289] in reed canarygrass under variable light and temperature regimes. Poor curing techniques [90] or genetic variation [289] may contribute to this variability.
Germination rates of reed canarygrass are consistently higher for seed germinated in light than in dark [44,92,117,173,180,289], and several studies indicate that light availability may influence reed canarygrass germination [173,179,180]. In the laboratory, little or no reed canarygrass seed germinated when buried at soil depths of 0.4 and 2 inches (1 and 5 cm), but nearly 100% of the seed germinated when it was transferred to the soil surface [173]. In an experimental wetland, reed canarygrass germination increased on sites where more light penetrated to the soil [179].
Temperature and moisture may influence germination of reed canarygrass seed. A few publications have indicated that exposure to alternating temperatures, rather than constant temperatures, may stimulate reed canarygrass germination [44,165,273]. However, McElgunn [198] observed >90% germination of reed canarygrass at both constant and alternating temperatures.
Percent germination of reed canarygrass seed relative to control (control=100% at constant 21 °C) at various temperature regimes [198] Temperature regime % germination 7 °C 94 2 °C/13 °C 46 10 °C 61 4 °C/15 °C 96 13 °C 64 7 °C/18 °C 94 16 °C/27 °C 97Reed canarygrass seed may germinate better in saturated soils than in dry or flooded soils [22,173]. In the laboratory, germination of reed canarygrass seed planted in saturated soils was higher (~100%) than seed planted in drained or flooded soils (~80%) [173]. Reed canarygrass seed exposed to light had higher germination rates after 30 days when submerged in water (85%) versus seed placed on moist filter paper (66%) [117]. Bonnilla-Warford and Zedler [22] speculated that reed canarygrass seed failed to germinate in pots placed in a controlled environment because the soil was dry.
Reed canarygrass' ability to germinate may be influenced by oxygen availability in the soil [173].
In the greenhouse, reed canarygrass has germinated immediately after ripening ([92,117,173], reviews by [7]), but it is unclear if this commonly occurs in the wild. Kilbride and Paveglio [148] implied that reed canarygrass seed germinates immediately after ripening in the wild, but no evidence was provided. In the greenhouse, fresh reed canarygrass seed germinated within 9 days [92]. In other greenhouse studies, an estimated 3% to 90% of fresh reed canarygrass seed grown in various substrates and temperature regimes germinated within 21 days [44]. Reed canarygrass seed germination rates may improve after undergoing a period of dormancy, at least through the winter. Both dry storage and cold-stratification have enhanced germination in reed canarygrass to a limited extent [117,289]. Germination rates for fresh reed canarygrass seed were lower (9-16%) than for seed that germinated the following growing season (34-85%) after undergoing cold-stratification [117]. Vose [289] described germination for various strains of reed canarygrass to be "poor and irregular" and attributed it to seed dormancy. In the laboratory, scarification may break reed canarygrass seed dormancy and increase germination; however, freshly scarified seed sown in soil may not germinate after 2 or 3 days [289].
Climate: Reed canarygrass is a circumboreal, cool-season grass [88,119] and is most productive in the spring and fall during periods of cool temperatures and plentiful moisture [32]. Reed canarygrass is considered winter-hardy [283], although different strains may be less adapted to cold than others. European strains may survive colder temperatures than some North American strains [152]. Reed canarygrass' net photosynthesis is maximized at temperatures of about 68 °F (20 °C) and reduced to 80% of maximum at 100 °F (38 °C), suggesting it may not perform well in subtropical or tropical climates [190].
A few localized examples illustrate that reed canarygrass tolerates a wide range of temperature and precipitation regimes. In North America, reed canarygrass occurs in areas where average annual low temperatures range from 9.5 °F (-12.5 °C) [216] to 40.5 °F (4.7 °C) [69,182] in the coldest month, and average annual high temperatures range from 59.2 °F (15.1 °C) [182] to 70 °F (21 °C) [69,216,284] in the warmest month. Reported average annual precipitation on sites where reed canarygrass occurs range from 18 inches (450 mm) [284] to 80 inches (2,000 mm) [41,127,182,216,264,284]. In North America, reed canarygrass occurs in locations where the majority of rainfall occurs seasonally [41,69,182,264,284] but the time of the year is variable.
Elevation: Information pertaining to reed canarygrass' North American elevational range comes from local floras or is anecdotal. Reed canarygrass tends to occur at low to middle elevations but occasionally occurs at high elevations. The following table may not reflect reed canarygrass' complete elevational range in North America.
Reported elevations for reed canarygrass in North America Geographic area Elevation Arizona - Crater Lake 8,000 feet [143] California below 5,000 feet [222]; below 5,200 feet [111] Colorado 4,500 to 9,000 feet [99]; lower valleys [295] Idaho 3,400 to 5,600 feet [94] Nevada 4,000 to 8,000 feet [142] New Mexico 5,500 to 7,500 feet [220] Oregon -Substrate and water chemistry: In North America, reed canarygrass occurs on a variety of soil textures from clay to sand [34,64,94,97,202,220,264]. In wetlands of the northcentral United States and the Great Lakes area, reed canarygrass commonly occurs in muck [23,51,95,189,220] and peat [11,23,51,73,206,307,310] deposits of varying mineral and organic content. A few reports indicate that reed canarygrass occurs in mineral soils [34,244] and muck [244,250] in the Northeast.
Riparian plant community publications from Idaho [6] and Montana [97] and studies from Wisconsin [157] and Ohio [206] indicate that reed canarygrass tolerates pH ranging from 6.0 to 8.1 in wetlands and riparian areas. In Tennessee, reed canarygrass was planted and survived on a site with soil pH as low as 5 [69]. In Alberta, Canada, reed canarygrass occurred in oxbow lakes with water pH ranging from 8.4 to 8.8, but in one oxbow, pH fluctuated between 7.5 and 10 [284].
Reed canarygrass may tolerate mildly saline water [140] but is intolerant of hypersaline conditions [200].
Moisture: Reed canarygrass prefers sites with moist to saturated soils [97,111,140,142,143,160,244,250,271,283,294]. Reed canarygrass has a wetland indicator status of "Obligate" (~99% probability of occurring in a wetland) in Alaska, California, the Southeast, Southwest, and Intermountain regions of the United States. Throughout its remaining United States distribution, it has a wetland indictor status of "Facultative Wetland" (67-99% probability of occurring in a wetland) [282]. Reed canarygrass tolerates flooding [32,190,204,220,257,277,301] and may prefer sites that experience periodic flooding [41,51,156,164,203,220,244,284,301], but for how long is unclear. Reports from northwestern states indicate that reed canarygrass may survive flooding lasting from weeks [204] to months [301], and up to 1 year if it is not totally submerged (review by [277]). In Canada, reed canarygrass seedlings survived periods of flooding lasting from 35 to 49 days [199]. In South Dakota, planted reed canarygrass seedlings inundated for up to 9 weeks survived and spread. Their cover was temporarily reduced when inundation lasted for more than 6 weeks, but they recovered before the next flood season [118]. In California, reed canarygrass established after being seeded in December but failed to survive 61 days of flooding on an experimental site [100]. In New Mexico, reed canarygrass tolerates anaerobic conditions [220]. Flooding has been recommended for reed canarygrass control in some situations, which suggests that reed canarygrass may not tolerate prolonged flooding in all circumstances.
Several publications suggest that reed canarygrass is drought tolerant [76,190,277,283,306], while others suggest it has little drought tolerance [204]. A publication from the Nature Conservancy indicated that in the Pacific Northwest, reed canarygrass tolerates "prolonged" periods of drought [277]. Conversely, Merigliano [204] considered reed canarygrass to have a "very low" tolerance to drought in riparian areas along the South Fork Snake River in Idaho. One laboratory study [139] indicated that reed canarygrass growth may be adversely impacted by drought (see Seedling establishment and plant growth). Statements made regarding reed canarygrass' tolerance to drought often come from agronomic sources [190,283,306] and are sometimes made in reference to other cultivated or upland grasses [76,190,306], so they are difficult to apply to wildland conditions. Reed canarygrass drought tolerance may differ among its numerous strains and cultivars [306].
General habitat: In North America, reed canarygrass occurs in marshes, wet meadows and prairies, lake shores, stream banks [9,15,87,131,142,158,187,195,241,250,252], and river islands [15,243,293]. Stream surveys from 12 western states indicate that reed canarygrass is significantly (P<0.001) more common along large streams than small [248]. Reed canarygrass also occurs in fens and bogs, particularly in the Rocky Mountains [252] and Great Lakes states [51,178,195]. In the Great Plains, it is common in prairie potholes, particularly those located in fallow and hayed fields [140]. Along the east coast it occurs in freshwater tidal marshes [34,67,173,229]. Throughout its North American range, reed canarygrass occurs in riparian forests [53,54,66,293], and in the northwestern and Great Lakes states, reed canarygrass may invade upland sites such as oak savannas [6,106,119,202] or upslope drainage seepages [57]. In Ohio, it occurred in a forested bog [206].
Reed canarygrass is common on anthropogenically altered sites such as ditches [87,238,295], agricultural fields that are under cultivation or abandoned [40,103,238,239], sites near water impoundment structures (e.g., dams, levees) [175,248], disturbed wetlands [11,109], and along highways [113] and roads [238]. It also establishes on sites where natural disturbance has occurred, such as flooding and wildfire (see Potential successional stages).
Although disturbance may facilitate reed canarygrass establishment, it is not a requirement [11,119,167,175,188]. In northwestern Oregon, reed canarygrass occurred in 89 of 93 wetlands surveyed; 45 were naturally occurring wetlands, and the remainder were disturbed and/or constructed wetlands [188]. In one study from Manitoba, Canada, reed canarygrass occurrence was negatively associated with disturbance and positively associated with plant diversity [213].
Immediate fire effect on plant: Reed canarygrass is top-killed by fire. In near-monocultures of reed canarygrass (>80% relative cover) in Wisconsin, 100% of the aboveground vegetation was top-killed by May burns, and 97% to 100% was top-killed by August burns [129].
Reed canarygrass rhizomes likely survive most low- to moderate-severity fires but may be killed by high-severity fires in some plant communities. Studies and observations indicate that reed canarygrass sprouts after fire (see Fire adaptations and Plant response to fire), suggesting that its rhizomes likely survive fire if they are buried deep enough in the soil (see Botanical description) to be protected from lethal heating ([39], reviews by [208,302]). Reed canarygrass sometimes occurs in wetlands with deep organic soils (see Habitat types and plant communities). When these sites are drained or experience severe drought, severe ground fires, such as those described by Curtis [51] in sedge meadows in Wisconsin, may smolder for long durations and consume organic surface layers, burning down to the underlying mineral soil or parent material [51,73,74,307]. Reed canarygrass rhizomes occurring in organic layers would be killed in these circumstances.
Studies in which reed canarygrass seedlings were observed after fire [1,69] indicate that reed canarygrass seeds in the soil seed bank survive fire and that germination may be stimulateded by fire or by postfire conditions. Less than 1 month after early spring controlled burns in monotypic stands of reed canarygrass in a wetland in northeastern Tennessee, reed canarygrass seedlings were growing from gaps in the litter on burned plots [69]. In Minnesota wet meadows undergoing restoration treatments, reed canarygrass' seeds survived and germinated "immediately" after spring prescribed fires that were described as being comparable to a "high-intensity grassland fire" [1]. No additional information was available (as of 2010) regarding how fire intensity and severity influence reed canarygrass seed survival.
Reed canarygrass is generally considered highly invasive within most of its North American range [37,133,148,168,197,251,303]. Several attributes may contribute to reed canarygrass' invasiveness in North America. Under cultivation, different strains of reed canarygrass vary greatly in vigor of growth, leafiness, seed retentioin, seed production, and resistance to drought [306] which may influence its invasiness. A review by Maurer and others [195] suggested that reed canarygrass is invasive because of high energy allocation to reproduction, clonal growth, long growing period, rapid growth, high productivity, and a broad tolerance to environmental variability. Under experimental conditions, reed canrygrass' rapid growth rate, tall leafy shoots, and extensive lateral spread of the canopy and rhizomes allowed it to effectively capture light and nutrients even under low nutrient and soil moisture conditions [300]. Disturbance may enhance reed canarygrass' invasiveness. In a controlled environment, reed canarygrass was more invasive where disturbance was common versus sites where little disturbance occurred [146].
Impacts: Hutchison [133] considered the nonnative type of reed canarygrass to be a "major threat" to North American wetlands, and NatureServe [224] gave reed canarygrass an impact-ranking of "high" based on its negative impacts to wetlands and riparian areas. Some of reed canarygrass' ecological impacts have been well documented, particularly in the Northwest and Great Lakes areas [15,31,35,66,145,188,234,240,248]. Reed canarygrass impacts ecosystems by reducing plant diversity [15,16,66,145,176,234], and may degrade wildlife habitat [35,110,210,248,270], interfere with wetland restoration [5,155,240,279], impede water flow [46,110], and/or influence succession.
Reed canarygrass is widely considered a threat to native wetland plant communities [5,23,58,122,144,188,195,256], and several studies document a loss of diversity in invaded communities [15,16,66,145,176,234]. In an Oregon riparian forest, increasing reed canarygrass abundance was correlated with decreasing species richness (R²=0.2455) and understory species diversity (R² =0.327) in stands older than 7 years [66]. In coastal wetlands in Oregon, high reed canarygrass cover near beaver impoundments was associated with a significant (P=0.01) reduction in species richness when compared to sites with low reed canarygrass cover [234]. In Wisconsin, Kercher and others [145] noted 21% fewer species in wetland plots containing reed canarygrass compared to reference plots, and 52% fewer species on sites where natural hydrological regimes had been altered. On a river island in Wisconsin, increases in frequency of nonnative grasses, including reed canarygrass, corresponded to decreases in frequency of numerous herbaceous species common to the island. The researcher concluded that reed canarygrass had a "major impact on plant species composition and diversity on the river island" [15].
Frequency (%) of common herbaceous species on a river island in Wisconsin over a 15-year period [15] Plant species Native status Growth habit 1981 1996 switchgrassReed canarygrass may displace rare plants like Nelson's checkerbloom (Sidalcea nelsoniana) in Oregon [16] and water howellia (Howellia aquatilis) in the inland Northwest [176].
Although there is concern for reed canarygrass' impacts to wildlife habitat (reviews by [5,110,210]), as of this writing (2010) there has been little documentation of these effects. In southwestern Minnesota and Wisconsin, Kirsh and others [151] studied riparian wet meadows dominated by reed canarygrass and their use by 4 common species of breeding birds. They determined that reed canarygrass had a negative effect on 1 species and a slight positive effect on 2 species [151]. Columbian white-tailed deer graze on reed canarygrass but prefer native wetland plant communities over monotypic stands of reed canarygrass [270]. In a survey of 12 western states, biotic integrity—based on vertebrate and macroinvertebrate occurrence— was significantly (P<0.001) lower on sites in mountainous regions where reed canarygrass occurred than where it was absent [248]. In western Washington, 158 coho salmon (an endangered species) migrating upstream during a high flood event became stranded and died in a field of reed canarygrass and pale-yellow iris (Iris pseudacorus) when flood waters receded quickly. Carrasco [35] speculated that dense stands of reed canarygrass and pale-yellow iris made escape from the field more difficult for the coho salmon, especially where the canal was ill-defined. The displacement of woody vegetation by reed canarygrass may reduce the number of arthropods foraging in riparian areas, which may in turn deprive juvenile salmon of an important food source (review by [210]).
Because reed canarygrass establishes in constructed or restored wetlands, it may interfere with the long-term success of wetland restoration projects [5,31,155,240,279]. On an experimental site in Minnesota, researchers evaluated the potential for native lakebank sedge (Carex lacustris) to establish in a former wetland dominated by reed canarygrass. After 3 years, mean biomass of sedge planted in plots with reed canarygrass was either unchanged or decreased [31]. Researchers in Minnesota speculate that reed canarygrass' large seed bank hinders wetland restoration [240].
Reed canarygrass may influence hydraulic flow of a streams [5,46,110]; however, empirical evidence is lacking. One review suggested that reed canarygrass impacts hydraulic characteristics of surface waters by clogging ditches and streams with thick thatch [5]. Comes and others [46] speculated that roots and rhizomes of reed canarygrass come in contact with water and moist soil, collecting silt and rapidly forming berms at the water's edge. Silt deposits and the emergent stems and leaves of reed canarygrass reduce the volume of water that a channel can carry and thus impede water flow [46]. An invasive plant guide from Alaska claims that reed canarygrass may slow stream flow and eliminate the scouring action needed to maintain salmon habitat [110].
Control: Reed canarygrass is difficult to control because it has vigorous, rapidly spreading rhizomes and forms a large seed bank [69,105,232,240]. Because reed canarygrass is typically found in wetlands, implementation of herbicide applications [133], mowing [263], or prescribed fire ([148], review by [8]) may be hindered or impractical on many sites. Additionally, past and present use of reed canarygrass for forage and erosion control may frustrate attempts to control it in wildlands [89].
Management strategies used for reed canarygrass control include mowing, herbicide, grazing, cultivation techniques, fire, shading, and flooding (review by [168]). Like control of most biotic invasions, control of reed canarygrass is most effective when it employs a long-term, ecosystem-wide strategy rather than a tactical approach focused on battling individual invaders [186]. Various types of publications including original research [1,18,148,161,260,305], reviews [184,251,277], and regional invasive plant management guidelines [119] generally agree that control of reed canarygrass is most effective when it includes an integrated approach implemented in a sequential and timely order. Implementing treatments based on reed canarygrass' growth characteristics and phenological stages (see Seasonal development and Seedling establishment and plant growth) may make it more vulnerable to treatment [1,251]. Regardless of which treatment options are used, the potential for post-treatment reinvasion by reed canarygrass [69,232] or other invasive species [29] should be considered. Ongoing maintenance to control sprouting and seedling establishment may be necessary to maintain long-term reed canarygrass control [1,161,305].
Prevention: It has been argued that the most cost-efficient and effective method of managing invasive species is to prevent their establishment and spread by maintaining "healthy" natural communities [186,258] (e.g., avoid road building in wildlands [280]) and by monitoring several times each year [138]. Managing to maintain the integrity of the native plant community and mitigate the factors enhancing ecosystem invasibility is likely to be more effective than managing solely to control the invader [115].
An invasive plant management guide suggested that reed canarygrass might be prevented from invading wetlands by constructing erosion screens and catch-basins around wetlands adjacent to eroding slopes [119]. Mauer and others [195] speculated that disturbance that creates canopy gaps may make a community more vulnerable to invasion by reed canarygrass and recommended maintaining a dense canopy to discourage reed canarygrass invasion. They also recommended the quick removal of new populations of reed canarygrass to prevent its spread [195].
Cultural control: Shading has been suggested as a control for reed canarygrass [5,119,149,236]; however, reed canarygrass' response to shade is not well understood [236]. Results from field and laboratory studies indicate that shade may reduce reed canarygrass' aboveground biomass but not its tiller production (see Shade tolerance).
Seeding and planting of native species have been used in conjunction with other treatments to control reed canarygrass (see Integrated Management and Use of prescribed fire), although reed canarygrass may quickly displace planted or seeded species if its rhizomes are not removed [69]. In reed canarygrass infestations, planted woody species may survive better than seeded species [69]. In Washington, within 2 years after planting willows in a monotypic stand of reed canarygrass, its biomass was reduced by 56.1% (where plantings were 0.91 m apart) and 68.0% (where plantings were 0.60 m apart) relative to controls. The decrease in reed canarygrass was attributed to increased shade from willows [149]. To control reed canarygrass, Iannone and others [134,135] encourage the use of long-lived native perennial species rather than native annuals or short lived-perennials [134,236], because the latter may prevent desired native species from establishing and result in a reed canarygrass-dominated community [135].
Hydrological manipulation: Reed canarygrass may establish by seed and/or rhizomes following drawdown, even on sites treated with herbicide [232]. Some have speculated that the draining of wetlands for agriculture may help to spread reed canarygrass [148] and that restoring water levels may help control reed canarygrass [133].
Flooding has been suggested as a control for reed canarygrass [133,137,153,167,251], and several studies have evaluated its potential. In Oregon, within 1 year of restoring historical flooding regimes to a slough, reed canarygrass cover was reduced by as much as 10.7% [137]. A Wisconsin marsh had been dominated by reed canarygrass, but it was nearly eliminated following 3 years of flooding and a subsequent drawdown [19]. In the greenhouse flooding to a depth of 2.6 inches (6.5 cm) above the soil surface for 1 month decreased rhizome survival and aboveground biomass by as much as 20% compared to plants grown in saturated or moist soils [196]. A study from the Czech Republic indicated that reed canarygrass' rhizome growth and tillering may be reduced by flooding, particularly flooding in the summer [153].
Occasionally reed canarygrass responds favorably to flooding. Reed canarygrass established in wetlands that were reflooded following a 5-year-drawdown [101]. In a controlled environment, reed canarygrass biomass was greater for plants exposed to prolonged flooding compared to nonflooded plants [146].
Flooding may be most effective at controlling reed canarygrass when timed to coincide with maximum rhizome growth and tillering [137,153] (see Seasonal Development). Lavergne and Molofsky [167] concluded that more empirical data are needed to assess whether hydrological manipulation, especially water levels and inundation periods, could limit reed canarygrass' vegetative spread. Gillespie [82] cautioned that using flooding for reed canarygrass control may be costly and water levels difficult to manipulate.
Physical or mechanical control: Hand-pulling reed canarygrass is too labor intensive and time-consuming for large stands (review by [133]), although it may be effective for controlling small stands (reviews by [8,119,133]). In an oak savanna in Wisconsin, hand-pulling controlled reed canarygrass when treatments were carried out 2 to 3 times a year over a 5-year period [105]. Covering reed canarygrass with black plastic or fabric may kill small stands of reed canarygrass [5,105,119,177,279], but rhizomes may survive (review by [119]). Covering may be more effective at controlling reed canarygrass if done in conjunction with other treatments such as mowing and native plant seeding [105,177].
Mowing, plowing, cutting, raking, and disking have all been evaluated for reed canarygrass control. If used independently, mechanical control typically produces short-term reed canarygrass control at best ([95,148,240,301], review by [133]). Often there is no long-term effect ([95,148], review by [133]), because reed canarygrass grows back from the seed bank [148,240] or may sprout from rhizomes or produce tillers from the root crown (see Vegetative regeneration). In some instances, cutting may increase reed canarygrass growth (review by [190]) and mowing may increase tiller production [279]. Mechanical treatments may be more effective at controlling reed canarygrass when included as part of a well coordinated integrated management plan.
Biological control: As of this writing (2010), no biological control agents have been developed for reed canarygrass. Reed canarygrass may not survive sustained grazing [97,283], but grazing may be impractical for reed canarygrass control in wetlands (review by [133]).
Chemical control: Some herbicides control reed canarygrass (review by [251]), especially when used in conjunction with other treatments such as fire, mechanical control, and/or native seed dispersal (see Integrated management). Studies documenting the long-term effects of herbicide treatments have found that when used independently, herbicides may provide short-term reed canarygrass control at best [1,69,105,177]. Even when used in conjunction with other treatments, several herbicide applications may be necessary to prevent its reestablishment from the seed bank or rhizomes [1,69,105,119,240,279,305]. In Tennessee, 1 application of herbicide failed to prevent reed canarygrass seedlings from establishing in a monotypic stand and may have facilitated germination by creating canopy gaps [69]. In Minnesota, 2 herbicide treatments (1 in late August and 1 in late September) did not reduce reed canarygrass seed bank densities compared to control plots (280 seeds/m²), but 2 years of herbicide treatments did (60-120 seeds/m²). Repeated late-season herbicide treatments, however, did not prevent remaining seed from germinating [1,305].
Herbicide treatments, whether used independently or in conjunction with other controls, may be more effective when timed to take advantage of reed canarygrass' vulnerable phenological stages ([1], review by [251]). Rosburg [251] suggested that early spring or late fall herbicide applications, coinciding with reed canarygrass' photosynthetically active periods, may improve herbicide selectivity and avoid stressing native species. In Minnesota, 2 years of fall herbicide applications, timed to coincide with optimal carbohydrate accumulation in reed canarygrass rhizomes, were twice as effective at controlling reed canarygrass as 2 years of spring applications [1]. In the eastern Great Plains area, reed canarygrass rhizomes survived spring herbicide applications; however, late October and early November application killed reed canarygrass rhizomes completely [161].
Glyphosate products, approved for use in aquatic environments, have been used to kill reed canarygrass [1,69,148,161,177,240,260,305] and are commonly recommended ([46,105,263], reviews by [5,133]) for its control. One study from Illinois [260] and another from Wisconsin [305] evaluated using sethoxydim to control reed canarygrass. Both studies indicate that, when used in conjunction with fire and glyphosate, sethoxydim may improve opportunities for native plants to establish [260,305] (see Use of prescribed fire); however, its use is limited to sites without standing water [260]. Occasionally, amitrol and dalapon have been recommended for reed canarygrass control, but they may not be appropriate for use in wildlands and aquatic environments ([46,116,263], review by [119]).
Herbicides are effective in gaining initial control of a new invasion or a severe infestation, but they are rarely a complete or long-term solution to weed management [33]. Additionally, most herbicides are not selective enough to treat reed canarygrass on wildlands ([177,263], review by [133]). See the Weed control methods handbook [278] for considerations on the use of herbicides in natural areas, particularly wetlands and riparian areas, and detailed information on specific chemicals.
Integrated management: Numerous studies [1,69,148,149,161,177,260,305] have evaluated various integrated management approaches to control reed canarygrass, and several offer potential control treatments [1,148,149,161,260,305]. Researchers have used combinations of mowing, herbicide, and fire to control reed canarygrass, and to a lesser extent disking, shading, black plastic, and flooding [1,5,69,148,149,161,177,200,260,305]. Treatments often include or are followed-up with a seeding or planting of native species [69,105,149,161,260,305]. Successful strategies require a multiple-year commitment including long-term maintenance. To obtain optimal results, treatments are typically carried out in a particular order and timing sequence. Several studies describe these sequences in detail [1,148,149,161,260,305].
Several studies report the effects of using fire in combination with other treatments to reduce reed canarygarss and are discussed in the Use of prescribed fire section.
Reed canarygrass has been cultivated extensively in North America [32,215,301] for livestock and wildlife forage [215]. Reed canarygrass is generally considered good forage for livestock, particularly cattle [97,148,190,256,283]; however, its ability to survive under continuous close grazing is questionable [97,283].
As of this writing (2010), reed canarygrass' importance to wildlife has not been well documented; most available information is anecdotal. A variety of wetland and upland birds [97,151,164,191], small mammals [97,124,272], amphibians [81], fish [97], and ungulates [270] may occasionally use reed canarygrass for forage, cover, and nesting [81,97,151,191,270], but may not prefer it over native plants in many situations [70,97,181,227,270]. Reed canarygrass may threaten wetland and aquatic wildlife habitat by displacing desirable native wetland plants (see Impacts).
Palatability and/or nutritional value: Reports on reed canarygrass' palatability are variable. Agronomic researchers [190,257] claim that lack of palatability in reed canarygrass is the most frequently cited reason why it is not agronomically superior to other forage grasses. Agronomic testing in Iowa found that reed canarygrass was palatable to horses and was preferred over timothy (Phleum pratense) [306]. In another palatability test, reed canarygrass was preferred forage for snow geese when compared to 3 other pasture grasses and 2 legumes [81].
It has been suggested that alkaloid concentrations [84,190,257], leaf texture [97], or plant maturity [79,97,257] may influence palatability and/or nutritional value of reed canarygrass. Some strains of reed canarygrass contain high concentrations of alkaloid compounds [230], making them unpalatable and/or toxic [84,190,257]. Hansen and others [97] speculated that reed canarygrass' palatability may be reduced by the coarseness of its leaves. Reed canarygrass' palatability and nutritional quality may decline as plants mature during the growing season [79,97,152,257]. Several strains of reed canarygrass have been developed with varying degrees of palatability [257]; as these strains establish in wildlands, they may influence forage quality in wild populations.
A review by Martin and others [191] states that reed canarygrass forage value is fair for upland game birds such as ring-necked pheasants and quail in the Northeast, northern bobwhite in Texas, and some songbirds including lazuli bunting, American Pipit (Pacific coast), savannah sparrow (California), and towhee (Alberta). Although reed canarygrass is a readily available food source in Montana wetlands, it is only occasionally used by waterfowl and small mammals [97]. A variety of ungulates, particularly moose and elk, and to a lesser extent, mule deer, pronghorn [97], and white-tailed deer [97,270], use reed canarygrass as forage. Columbian white-tailed deer were observed grazing reed canarygrass, although use was relatively low on sites where it formed dense monotypes compared to other wetland plant communities [270]. Studies have documented common muskrats [272] and voles [124] foraging on reed canarygrass, but it is unclear if it is an important food source to either.
Cover and nesting value: In Montana, reed canarygrass is often used for cover by mule deer, white-tailed deer, and moose but rarely by elk. It provides fair cover for upland game birds, non-game birds, and small mammals, and good cover for waterfowl. On sites inundated long enough, stands of reed canarygrass provide cover for common muskrat [97]. Amphibians [81] and fish [97] may use reed canarygrass for breeding.
In Wisconsin, ring-necked pheasants nested on sites where reed canarygrass had been planted along with other nonnative grasses and forbs. However, on muck and peat soils, ring-necked pheasants preferred native bluejoint reedgrass over reed canarygrass when it was available [70]. Reviews from the Great Plains [269] and Montana [97] indicate that waterfowl occasionally nest in reed canarygrass. In Oregon, greater sandhill cranes occasionally used reed canarygrass for nesting but preferred spikerush [181]. Greater prairie-chickens may use reed canarygrass for roosting [275] and nesting in areas where native grasslands are scarce; however, cutting reed canarygrass for hay may decrease its nesting value if done before chicks fledge [227].
Stands of reed canarygrass may provide spawning areas and hiding cover for many species of fish [97]. One study from Quebec indicates that reed canarygrass may provide important habitat for the northern leopard frog, a species that has been commercially exploited and whose populations are in decline. In a wet meadow, northern leopard frogs preferred reed canarygrass for egg mass support (65% of egg masses) over red-osier dogwood (15%), purple loosestrife (13%), prairie cordgrass (3%), and willow (2%) [81].
The following is a summary of available literature on reed canarygrass phenology from various parts of North America.
In North America, reed canarygrass begins to grow in early spring, typically April [5,133,157,294,301]. One report from the Great Plains [117] and another from New Jersey [171] indicate that reed canarygrass seedlings emerge in the spring. In the Pacific Northwest, reed canarygrass may begin to grow in late winter (review by [5]). Reed canarygrass continues to grow vertically throughout the spring and early summer ([301], review by [133]) and then may start to expand laterally via rhizomes (review by [133]). In Oregon, reed canarygrass grows substantially in the spring before flood waters recede [301]. Various reviews from the Pacific Northwest [148], Illinois [133], and Wisconsin [157] indicate that reed canarygrass' growth peaks in mid-June and declines by mid-August. On an experimental site in Ohio, reed canarygrass rhizome production peaked in June and declined through August. Peak rhizome production was associated with a decline in culm production [62,63].
In North America reed canarygrass generally flowers from May through early June but in some locations it may continue to flower into July and August (see Table below). In Iowa [121] and Ohio [63], initiation of the inflorescence may occur in early to mid-April. Flowering may be delayed at latitudes experiencing shorter days. In the greenhouse, plants exposed to more than 12.5 hours of daylight flowered in late May, but flowering was delayed until late June in plants exposed to 12.5 hours of daylight [3].
Dates for reed canarygrass fruit maturation are variable (see Table below). In the Pacific Northwest, reed canarygrass seed matures in late July and early August. In the north-central states, reed canarygrass seed heads usually appear the first week in June, begin to ripen the last week in June, and mature the first week in July [301]. In Wisconsin, reed canarygrass seed maturation and dispersal occur during the latter part of June ([157], review by [119]). In New Jersey, reed canarygrass generally produces seed in early summer [173].
Reported flowering and fruiting periods for reed canarygrass in North America by geographic area Geographic area Flowering and/or fruiting periods California Flowers: May-Aug [222] Illinois Flowers: May-July [214] Iowa Spikelets emerged: May 2 [121] Nebraska Flowers: July-August [264] Nevada Flowers: June-August [142] North Carolina Flowers and Fruits: June [241] North Dakota Flowers: around June 20th [265] West Virginia Flowers: June-July [268] Wisconsin Flowers: May through mid-JuneA 3-year study showed that carbohydrate content of reed canarygrass rhizomes was lowest early in the growing season and increased later in the season. Rhizome carbohydrate content began increasing in mid- to late July and typically continued until mid-November, although in one year carbohydrate accumulations stopped after late August. Rates of carbohydrate storage varied from year to year. Between late July and late August, average rates of carbohydrate accumulation were 0.46 g/g/day the 1st year, 0.15 g/g/day the 2nd year, and 0.12 g/g/day the 3rd year. Researchers could find no explanation for this variability and felt it merited further investigation [1].
After reed canarygrass seed matures and is dispersed, the heads and stem die back to the upper leaves, but the rest of the plant stays green [301]. In the Great Plains, reed canarygrass' panicle may turn brown by midsummer and the lower leaves may die and form a thick mat [294]. A vegetation management guideline indicated that in Wisconsin, reed canarygrass' shoots collapse in mid to late summer, forming a dense, impenetrable mat of stems and leaves [119]. Reed canarygrass may undergo a period of additional growth in the fall ([157], review by [119]). Buds form on the rhizomes in late summer or fall and may develop into flowers on the culms during the next growing season [121]. New shoots develop primarily in the fall and the following spring [63].
Plant response to fire: Established reed canarygrass typically persists [1,69,105,260] and may increase in abundance [1,105,200,279] after fire, and fire may stimulate reed canarygrass seed germination [1,69]. None of the literature reviewed described postfire mortality of established reed canarygrass. Reed canarygrass' response to fire may be influenced by timing of fire and plant phenology, fire intensity and/or severity, presence and abundance of fire-tolerant native plants, and other ecological processes. When fire is used as part of an integrated management plan, reed canarygrass' response to fire may be influenced by the timing and sequence of other treatments (see Use of prescribed fire as a control agent).
Postfire persistence and spread: On sites where reed canarygrass is well established, it may persist and grow rapidly after fire [1,69,260,279], and in some instances it may spread [105]. In a monotypic stand of reed canarygrass in Tennessee, there was no significant (P>0.05) difference in live reed canarygrass root or shoot biomass for burned and unburned plots approximately 5 and 17 months after a spring (March) prescribed fire [69]. In a monotypic stand of reed canarygrass on a site that was historically sedge meadow and wet prairie in northeastern Illinois, reed canarygrass persisted after a low-severity prescribed fire in early March and was 6 to 12 inches (15-30 cm) tall by early May [260]. In a "large" stand of reed canarygrass in Oregon, tiller production was greater in plots after they were burned than before [279]. In a near-monotypic stand of reed canarygrass in Minnesota, reed canarygrass' shoot density was higher in burned plots (1,180 shoots/m²) compared to control plots (520 shoots/m²) 4 weeks after prescribed fire; however, by the 12th week overall biomass was similar in burned and unburned plots [1]. Where reed canarygrass was invading an oak savanna in Wisconsin, early spring fire appears to have "accelerated its spread" [105]; however, late spring burning had negative impacts on reed canarygrass.
Reed canarygrass may not always persist after fire. In a 3 year study, a small patch (0.5%) of reed canarygrass was found the 1st year after a mixed-severity wildfire in a wet sedge meadow in northwestern Montana, but it failed to persist beyond the 1st postfire year. No information was provided regarding the abundance of reed canarygrass either before the fire or in unburned areas. Beaked sedge dominated both the burned and unburned areas in the 3 years after the fire [307].
Reed canarygrass' rapid postfire establishment from the soil seed bank [1,69] suggests that postfire conditions may favor its germination. In a reed canarygrass field in Tennessee where seasonal flooding had recently been restored, reed canarygrass seedlings established within 1 month after prescribed fire [69]. On sites dominated by reed canarygrass in Minnesota, reed canarygrass seed density in the soil after a low-severity spring prescribed fire was significantly (P=0.03) less than in unburned plots. Researchers attributed the difference to germination of reed canarygrass seeds immediately after fire [1], although preburn seed densities were not reported for either burned or unburned plots.
Influence of fire frequency on As of this writing (2010), little information is available on the effects of fire frequency on reed canarygrass. Vegetation management publications recommend late spring or late fall prescribed fire repeated annually for 5 to 6 years to reduce reed canarygrass abundance [119,133,263] but provide no examples to support this recommendation. Reed canarygrass may persist after repeated fires, especially where it is a dominant or codominant species. Nearly monotypic stands of reed canarygrass persisted after 3 consecutive years of spring prescribed fires in an eastern Tennessee wetland [69]. In Wisconsin, reed canarygrass was a codominant species in a wet-mesic prairie that had been burned for 30 years on at least a biennial basis. While it is unclear when reed canarygrass established on the site, its relative dominance in the plant community suggests its invasion was not recent [42]. Frequent prescribed fires may be effective for controlling reed canarygrass in plant communities where desired, fire-adapted species dominate the plant community or seed bank (reviews by [119,133]) (see Use of prescribed fire as a control agent).
Influence of fire season on plant response to fire: The effects of fire season on reed canarygrass vary and probably depend on interactions with other variables such as plant community associates, fire frequency, and fire timing relative to plant phenology.
Howe [126,127,129] has conducted the only studies to date (2010) that investigate differential effects of fire season without other, confounding treatments. This research indicates reed canarygrass may be reduced by spring burning and increased by summer burning, but summer burning is unlikely to favor reed canarygrass to the point where it becomes dominant in areas previously dominated by warm-season grasses. Details of Howe's studies are described in the research project summary, Herbaceous responses to seasonal burning in experimental tallgrass prairie plots.
The first of Howe's studies [126,127] investigated the seasonal effects of fire in agricultural fields where vegetation was removed and tallgrass prairie species planted. Reed canarygrass was not one of the species planted but, within 3 years, was among the 12 most common species on the site. In the 4th year, one-third of the plots were burned in spring, one-third were burned in summer, and the remaining one-third were left unburned. The following year, reed canarygrass cover and frequency did not differ significantly among treatments [126]. Three years later, the same experimental plots were burned in the same seasons. The following year, mean reed canarygrass cover in summer-burned plots (18.6%) was significantly greater than in either spring-burned (1.5%) or unburned (3.5%) plots [127]. The summer after the second burn, warm-season plants dominated all plots regardless of treatments but were less abundant in plots burned in the summer than those burned in the spring or not burned at all. In contrast, cool-season plants, including reed canarygrass, were reduced in spring-burned and unburned plots but increased in summer-burned plots, although they did not become dominant. Howe [127] concluded that summer burns in this plant community reduced abundance of warm-season plants, allowing cool-season plants, such as reed canarygrass, to persist and even “prosper” [127].
A second study in the same area [129] described abundance of red canarygrass relative to that of other cool-season grasses and 3 warm-season grasses. Experimental plots were cleared of previous vegetation, then seeded with reed canarygrass and 2 other cool-season grasses (slender wheatgrass (Elymus trachycaulus) and Virginia wildrye (Elymus virginicus)); and 3 warm-season grasses (big bluestem (Andropogon gerardii), switchgrass (Panicum virgatum) and prairie dropseed (Sporobolus heterolepis)). Within 2 years of seeding, plots had become a near monoculture (97% relative cover) of reed canarygrass. Six plots were burned in May 1995 and again in May 1997; 6 were burned in August 1995 and again in August 1997; and 6 plots were left unburned. After the second burns, 2 warm-season species, big bluestem and switchgrass, increased in dominance in spring-burned plots while reed canarygrass, a cool-season species, decreased. In summer-burned plots, reed canarygrass was expected to increase substantially. Instead it codominated with the other 2 cool-season grasses (Virginia rye and Kentucky bluegrass) and the warm-season grasses [129].
In an oak savanna in Wisconsin, an early April prescribed fire did not control reed canarygrass and may have accelerated its spread. Late spring burning (mid-to-late May) weakened reed canarygrass and prevented it from producing seed but was also detrimental to some of the desired native plant species [105].
Influence of flooding on Effects of fire on reed canarygrass may be influenced by flooding. In northern California, reed canarygrass was a subdominant species in wetlands that were dominated by quackgrass (Elymus repens) or saltgrass (Distichlis spicata). Wetlands were burned in December 1990 and again in November 1991 to study the effects of prescribed fire on plant species diversity, plant community composition and plant community use by wild geese. Fire had little effect on reed canarygrass relative abundance in the saltgrass community. In the quackgrass community, reed canarygrass relative abundance increased after both fires; however, it was less abundant in burned blocks than expected in the year when spring flooding was "extensive". The authors recommended further study of the interactive effects of burning and flooding on reed canarygrass abundance [200].
Reed canarygrass spreads within established populations by creeping rhizomes ([80], reviews by [133,184,228,277]) and tillers [46,153,193,219] and colonizes new sites by seed (review by [184]). Ribbon grass may be sterile [14].
Available evidence suggests that reed canarygrass forms a soil seed bank ([19,72,172,173,240,276], review by [119]), but seed longevity is unclear. In Minnesota, reed canarygrass seedling establishment after control treatments led researchers to conclude that it forms a large seed bank [240]. Leck [173] indicated that reed canarygrass seed remains viable in the soil for more than 1 year. In germination tests, percent germination of reed canarygrass seed declined with increased age. Germination was 87% for 3-month-old seed, 77% for 6-month-old seed, and 65% for 1-year-old seed [92]. A small percentage of reed canarygrass seed remained viable after 20 or more years of burial. Viability was influenced by burial depth; reed canarygrass seeds buried at 22 inches tended to have higher percent germination than those buried at shallower or deeper levels [86,276].
Percentage of reed canarygrass seeds germinating after 1 to 39 years of burial. Seed was originally buried in 1902 [86,276]. Depth buried (inches) Years buried 1 3 6 10 16 21 30 39 8 45 40 30 13 12 5 0 --- 22 47 62 53 47 7 12 1 0 42 57 63 38 16 0 1 0 0Reed canarygrass seed in the soil seed bank may remain viable after periods of inundation [19,199], but seed floating in the water may lose viability relatively quickly [45]. A portion of reed canarygrass seed in the soil seed bank remained viable for at least 56 days of simulated spring flooding [199]. In a marsh in southeastern Wisconsin, reed canarygrass seedlings germinated from soil that had been previously flooded for 3 years [19]. In Washington, 16% of reed canarygrass seeds submerged in a column of water for 3 months germinated, and 7% of seeds submerged for 12 months germinated. No reed canarygrass seed germinated after being submerged in water for 24 months [45].
Reed canarygrass' soil seed bank densities may be high. In a New Jersey tidal wetland, estimated soil seed bank densities ranged from about 100 to over 5000 seeds/m² at a depth of 2 cm [172]. In two reed canarygrass-dominated (75-100% cover) wet meadows in Minnesota, reed canarygrass seed bank densities averaged 475 and 862 seeds/m² [1]. In Wisconsin, seed densities were estimated in 5 wetlands that were dominated by either sedge and reedgrass (meadow) or cattail. At a 5-cm depth, reed canarygrass average seed densities ranged from 0 to 1126 seeds/m² when germinated under wet conditions and 0 to 211 seeds/m² when germinated under flooded conditions [72].
Mean estimated reed canarygrass seed densities in soils of different wetland communities and relative abundance of reed canarygrass in aboveground vegetation [72] Site Vegetation Mean seed density (seeds/m²) at a 5-cm depth estimated by seedling emergence under wet or flooded conditions Mean relative abundance in aboveground vegetation (%) Wet Flooded Oconto Meadow 0 0 0 Cattail 282 0 0 Little Sumico Meadow 1,126 0 0 Cattail 352 0 0 Long Tail Meadow 634 211 4.7 Cattail 0 0 0 Peter's Meadow 0 0 0.8 Cattail 0 0 0 Atkinson Meadow 0 0 0 Cattail 0 0 0.6It is unclear how reed canarygrass' aboveground cover influences seed bank densities. In Wisconsin wetlands, estimates of reed canarygrass seed bank density ranged from 211 to 634 seeds/m² on sites where it was most abundant in the aboveground vegetation (4.7% relative abundance). However, average seed bank density estimates were highest (1,126 seeds/m²) on a site where reed canarygrass was not present in the aboveground vegetation [72] (see Table above). In a constructed New Jersey wetland, reed canarygrass seed bank frequency was greatest (67%) where reed canarygrass aboveground frequency was greatest (42%). On 2 other sites where reed canarygrass aboveground frequency was 8%, seed bank frequency was 25% and 50% [174]. In France, reed canarygrass' frequency in an alluvial floodplain meadow under cultivation ranged from 1% to 90%; however, no reed canarygrass germinated from soil samples taken at a 4-inch (10 cm) depth [285].
Reed canarygrass seed is passively dispersed [92] by gravity ([47,90,301,306], reviews by [12,119,257]). Seeds ripen from the tip of the panicle downward ([90,301], review by [12]) and are dispersed almost as soon as they ripen ([90,301,306], reviews by [12,119,257]). The ripening period extends over several days [306].
Reed canarygrass seed may maintain buoyancy for a few days after it falls [47], so it may be further dispersed by water ([47], reviews by [119,136]). Reed canarygrass seed has an adhesive quality [288] and may be dispersed by adhering to machines, humans (review by [119]), and other animals ([288], review by [119]). Reed canarygrass seed was found on feet and feathers of waterfowl. Animals may provide long-range seed dispersal of reed canarygrass and help deposit seed in sites more favorable to germination than seed randomly dispersed by water [288]. Ishida [136] indicated that reed canarygrass seed is also dispersed by wind, although details were not provided.
Reed canarygrass seeds used in germination studies had an average length of 4.15 mm [92] and weighed an average of 0.32 [47] to 1.05 mg [92,173]. Reed canarygrass spikelets are 3-flowered; 1 is fertile, the other 2 are sterile [64,83,112,238,298]. Reed canarygrass seed production is highly variable within and between populations [47,172,266,283,301,306]. In a New Jersey wetland, reed canarygrass seed rain counts over a 2-year period ranged from less than 10 to nearly 1,000 seeds/m² [172]. In North Dakota, 1 stem of reed canarygrass produced 120 seeds [266]. In the Pacific Northwest, individual inflorescences produce approximately 600 seeds on average (review by [277]). In the Netherlands, reed canarygrass averaged 393 seeds/flowering shoot [47]. Under cultivation, reed canarygrass yields 30 to 150 pounds of seeds/acre [283,301,306] depending on the strain [306] but may produce as much as 500 pounds/acre [301]. Reed canarygrass seed production may be limited during the first year of growth and increases with increased clone size [146,259].
Because flowering may increase with increased day length [3], reed canarygrass seed production may be greater in latitudes with longer days. In the greenhouse, Allard and Evans [3] found that reed canarygrass flowered more with longer daylight. When reed canarygrass was exposed to 10 to 12 hours of light it produced few decumbent flowers and no stems, only leaves. Flower stem production occurred when daylight increased to 14.5 hours or longer, and more flowers were produced [3].
Seedling establishment may be most common on moist open sites (review by [76]) such as mud flats [157], seasonal floodplains [153], and reservoir shores [117]. Reed canarygrass seedlings generally emerge within 8 to 10 days from seed planted in spring [45,63]. In a tidal wetland in New Jersey, seedling counts ranged from about 80 to nearly 120 seedings/m² [172]. Under cultivation, spring seedlings grow 10 to 20 inches (30-50 cm) tall [301] and may spread 6 to 10 inches (15-25 cm) in diameter within the first year [306].
Once established, reed canarygrass seedlings undergo rapid development ([46,301,306], review by [7,148]) from rhizomes ([46], review by [148]) and tillers [46], provided suitable substrate and moisture are available ([117,157], review by [76]). In an experimental field, tillering began within 1 month after seedlings emerged, and average tiller production increased from 0.5 tiller/seedling during the 1st month of growth, to 5.5 tillers/seedling after 10 weeks [46].
Under cultivation, different strains of reed canarygrass vary greatly in vigor of growth [306]. Wild populations likely share the same variability because they are thought to be an assemblage of introduced strains (see Native Status in North America). Results from several studies suggests that reed canarygrass can grow rapidly once it has established [62,157,204,294]. One review indicated that reed canarygrass grows most rapidly during the cool spring months [283]. In a Wisconsin marsh, reed canarygrass grew throughout the growing season but its maximum growth occurred from 26 April to 10 June [157]. Reed canarygrass shoots emerging in spring in a Missouri floodplain generally reach a foot high in April and up to 3.5 feet (1.1 m) tall by July [294]. Reed canarygrass may reach 4 to 5 feet (1-2 m) tall within 2 to 4 years [204,301] and may grow more rapidly on open than shaded sites (see Shade tolerance).
Under experimental conditions, increases in nitrogen and phosphorus concentrations typically have a positive influence on reed canarygrass biomass [20,67,108,146,147,193,300] and tiller production [193,196] and may have similar influences in wetlands [193]. Plant survival rates, however, may not improve with increased nutrients [67].
Several studies have documented increases in reed canarygrass' aboveground growth with increased flood duration [108,146,209], and one study found that submerged reed canarygrass maintains its photosynthetic capabilities for at least short periods of flooding [286]. Conversely, reed canarygrass growth may be adversely impacted by extended periods of flooding [26,47] or anoxia [13]. One study from western Europe indicated that reed canarygrass' growth may be adversely impacted by extended periods of drought [139].
The scientific name of reed canarygrass is Phalaris arundinacea L. (Poaceae) [14,83,87,111,113,141,187,192,298]. A variegated type, Phalaris arundinacea var. picta L. or ribbon grass,
also occurs in North America [14]. Reed canarygrass has been bred for cultivation and at least 11 cultivars have been
developed [102].
Terminology used to describe reed canarygrass' phenotypic variability (e.g., strains, types, genotypes, ecotypes) is inconsistent in the literature. This review uses the terminology from the original publications unless it is unclear and/or inconsistent with that in other pertinent
literature.
Vegetative regeneration: Within the first year of growth, reed canarygrass produces rhizomes and begins tillering [62,219]. In the greenhouse, reed canarygrass seedlings formed rhizomes before the plants were 2 months old and produced tillers soon after [219]. Mature reed canarygrass plants spread rapidly by rhizomes (Klimesova and Cizkova 1996 cited in [228]). Up to 74% of new shoots may originate from rhizomes; the remainder develop from buds located in the leaf axils of aboveground shoots [63]. In the greenhouse, transplanted rhizomes branched up to 7 times in one year [62]. In Europe, 3 to 5 generations of tillers were produced by 1 reed canarygrass plant in 1 year. Occasionally culms became inclined, and if the topsoil was moist, they rooted at the nodes and produced new upright stems [219]. Flooding may reduce rhizome growth [153,209] and tiller production ([153], review by [251]), particularly if it occurs in the summer [153]. Shade may also have an adverse affect on rhizome survival [196].
Reed canarygrass rhizome fragments sprout in controlled environments [22,196] and likely do so in the wild. Reed canarygrass abundance in a monotypic stand was reduced 1 year after soil scarification, but plants continued to sprout from rhizome fragments [148]. Reed canarygrass regrows following cutting, mowing, or other types of damage ([82,148,161,260,301], review by [251]) probably from its rhizomes and possibly from its root crown.
Phalaris arundinacea, or reed canary grass,[1] is a tall, perennial bunchgrass that commonly forms extensive single-species stands along the margins of lakes and streams and in wet open areas, with a wide distribution in Europe, Asia, northern Africa and North America.[2] Other common names for the plant include gardener's-garters and ribbon grass in English, alpiste roseau in French, Rohrglanzgras in German, kusa-yoshi in Japanese, caniço-malhado in Portuguese, and hierba cinta and pasto cinto in Spanish.[3]
The stems can reach 2 metres (6.6 ft) in height.[4] The leaf blades are usually green, but may be variegated. The panicles are up to 30 centimeters long.[4] The spikelets are light green, often streaked with darker green or purple.[5] This is a perennial grass which spreads underground by its thick rhizomes.[4]
A number of cultivars of P. arundinacea have been selected for use as ornamental plants, including variegated (striped) cultivars – sometimes called ribbon grass – such as 'Castor' and 'Feesey'. The latter has a pink tinge to the leaves.[6] When grown, although drought-tolerant, it likes abundant water and can even be grown as an aquatic plant.[6]
Reed canary grass grows well on poor soil and contaminated industrial sites, and researchers at Teesside University's Contaminated Land & Water Centre have suggested it as the ideal candidate for phytoremediation in improving soil quality and biodiversity at brownfield sites.
The grass can also easily be turned into bricks or pellets for burning in biomass power stations.[7] Furthermore, it provides fibers which find use in pulp and papermaking processes.[8]
P. arundinacea is also planted as a hay crop or for forage.
This species of Phalaris may also be used as a source for the psychedelic drugs DMT, 5-MeO-DMT and 5-OH-DMT (bufotenin), as well as Hordenine and 5-MeO-NMT;[9] however, N,N-DMT is considered most desirable. Although the concentrations of these compounds is lower than in other potential sources, such as Psychotria viridis and Mimosa tenuiflora, large enough quantities of the grass can be refined to make an ad hoc ayahuasca brew.
In many places, P. arundinacea is an invasive species in wetlands, particularly in disturbed areas.[10] It has been reported as an invasive weed in floodplains, riverside meadows, and other wetland habitat types around the world. When P. arundinacea invades a wetland, it inhibits native vegetation and reduces biological diversity.[11] It alters the entire ecosystem.[12] The grass propagates by seed and rhizome,[10] and once established, is difficult to eradicate.[13]
P. arundinacea now has world-wide distribution. It is regarded as native to both North America and Eurasia, but this is debated and it appears that the populations in North America are made up of a mixture of cultivars of both those that were introduced from Europe and indigenous varieties.[14]
Specimens contain varying levels of hordenine and gramine.[15]
Leaves of P. arundinacea contain DMT, 5-MeO-DMT and related compounds.[16] Levels of beta-carbolines[17] and hordenine[18] have also been reported.
A variegated form of Phalaris arundinacea in the garden of Islington College, Nepal Phalaris arundinacea, or reed canary grass, is a tall, perennial bunchgrass that commonly forms extensive single-species stands along the margins of lakes and streams and in wet open areas, with a wide distribution in Europe, Asia, northern Africa and North America. Other common names for the plant include gardener's-garters and ribbon grass in English, alpiste roseau in French, Rohrglanzgras in German, kusa-yoshi in Japanese, caniço-malhado in Portuguese, and hierba cinta and pasto cinto in Spanish.
