| BEN |
| BOTANICAL ELECTRONIC NEWS |
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| ISSN 1188-603X |
| No. 324 March 16, 2004 | aceska@victoria.tc.ca | Victoria, B.C. |
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An alien race of Common Reed (presumably the European Phragmites australis (Cav.) Trin. ssp. australis) has been rapidly spreading along roadsides and invading and dominating wetlands in parts of southern Ontario and Quebec since the early 1990s (Schueler 2000a, b, Robichaud & Catling 2003, Catling et al. 2003). The invasion and domination of native plant communities led to a substantial reduction in native biodiversity (e.g. Catling et al. 2003, Lavoie et al. 2003). Very recently the status of the alien race has been clarified in other parts of Canada (e.g. Martin 2003, Schueler et al. 2003). However, in the Canadian maritime provinces its status has been unclear until recently when both field study and a database of herbarium records was completed. The herbarium records database includes data from all major herbarium collections in Canada (including those of particular importance with regard to the maritimes such as ACAD, CAN, DAO, MT, MTMG, NFLD, NSPM, UNB). The value of herbarium specimens in understanding status and spread was increased when a method of distinguishing the races using the floral character of lower glume length (Robichaud & Catling 2003) made it possible to identify many herbarium specimens lacking the distinctive lower stem characters. .The alien invasive race was distinguished from the native race by having first glumes 4.1 mm long or less and lower stem internodes yellow or brownish instead of reddish-purple (Robichaud & Catling 2003). A chemical method for distinguishing the races has also recently become available (Saltonstall 2003). The following notes, arranged by province, are derived from response to several questions regarding the status of the alien race in the maritime region.
The only record is that of a specimen collected from Stephenville Barachois by R. Day in 1991 (DAO). The native race has apparently not been recorded in the province.
Of the locations mapped by Hinds (2000, p. 606), only that collected from 2 km S of Beaver Dam in Sunbury County by H. R. Hinds in 1981 (MTMG, UNB) was referable to the introduced race. A depauperate specimen from the salt marsh at St. Louis Cape in Kent County collected by P. R. Roberts and B. Pugh in 1965 (UNB) has a lower glumes approx. 4.0 mm long but lacks stem and was not assigned to race. In 2003 the alien race was collected by P. M. Catling at two locations on the Trans Canada highway at Sackville (DAO). Here it occurred within 20 m of the paved edge of the highway. From here it may spread into the adjacent Tantramar Marshes and displace the native race of P. australis, (which is presumably referable to ssp. berlandieri, see Fernald 1932). Schueler (2000b, 2002) found Phragmites australis absent from sides of major roads in New Brunswick (and Prince Edward Island) so that the occurrence in the Sackville area along the major highway is almost certainly a recent phenomenon. This conclusion is supported by the small size of the clones present, i.e. only several m2.
At the present time only the native race is known from Prince Edward Island and it is considered rare in the province (Day & Catling 1991). It was collected from the Dunk River estuary in Bedeque by M. L. Fernald and H. St. John in 1914 (CAN, MT) and later by D. Erskine and A. J. Smith in 1953 (DAO, MT). Plants reported from Lennox Island (Day & Catling 1991) have not been seen.
Most of the locations mapped for Nova Scotia (Roland & Smith 1969, Zinck 1998) represent the native race. The obvious exceptions are the specimens from Annapolis Royal and Bridgetown. The alien race was first collected at Annapolis Royal in by J. Macoun in 1910 (CAN), and subsequently by M. L. Fernald and B. Long in 1921 (ACAD, CAN, MT), by H. E. Perry and M. V. Roscoe in 1928 (ACAD), by G. C. Warren in 1938 (ACAD), W. G. Dore in 1940 (DAO), F. Kinsman in 1949 (DAO), M. S. Brown in 1949 (NSPM), P. Douglas in 1949 (NSPM), J. R. Jotchan in 1978 (ACAD), E. Specht in 1979 (ACAD), P. M. Catling, S. Carbyn and J. Achenbach in 2003 (DAO). It is believed in Annapolis Royal that the alien race was introduced with straw on trains carrying Elephants and other circus animals in the early 1900s (J. Achenbach, pers. comm.). It is locally called Elephant Grass. For many decades the occurrence of this gigantic (to 4 m tall in one season) grass in and around Annapolis Royal was recognized as a remarkable occurrence. Interestingly the Common Reed growing around Annapolis Royal was used to thatch a restored Acadian dwelling in the same way that the Acadians used the native race. Prior to the dyking which began around 1700, the native race may have been much more abundant in the Fundy tidal marshes.
The alien race was also recorded relatively early at Bridgetown. Here H. G. Perry and M. V. Roscoe made a collection in 1928 (ACAD, MTMG, NSPM). Despite the continuity of collections from Annapolis Royal, there was a gap of 44 years until another locality of the alien race was recorded, this being from South Brookfield where it was collected by P. L. Comeau and J. M. Stanley in 1972 (NSPM). There are several more recent collections; Big Pine Lake by M. Zinck and R. Ogilvie in 1992 (NSPM), Sable River by R.E. and R.B. Newell in 1993 (ACAD), south side of Annapolis River at Middleton by P.M. Catling in 2003 (DAO), junction of Trans Canada Highway 104 at Highway 102 by P. M. Catling (DAO), Highway 101 at Grand Pré by S. Carbyn in 2003 (DAO), 2 km W of Dodge Road overpass on Hwy 101 3 km W of exit 17 (Kingston/Greenwood) by S. Carbyn in 2003 (DAO),1 km W of exit 16 Hwy 101(Aylesford exit) by S. Carbyn in 2003 . All of these are within 20 m of a paved road suggesting that vehicles and roads are the means and pathway of invasion.
Although the alien race became established in the maritimes almost 100 years ago, it appears to have spread only recently and is apparently spreading by means of vehicle traffic on roads. This parallels the situation elsewhere in eastern Canada (Catling et al. 2003). Although the alien race is invading agricultural land, including cornfields in southern Quebec, its most serious impact to date has been the replacement of diverse native vegetation in wetlands with significant loss of biodiversity in general. Considering its impact on Atlantic coastal marshes in the United States (e.g. Blossey 2002, Marks et al. 1994, Meyerson et al. 2000), marshes along the St. Lawrence River (e.g. Lavoie et al. 2003) and wetlands in southern Ontario (pers. ob.), it is considered a threat to the biodiversity of the Bay of Fundy marshes. Since its spread into much of the region is recent, there is an opportunity for regional control, especially around major brackish marshes. For example, invasion of the upper levels of the Tantramar Marshes, at the head of the Bay of Fundy, may be prevented by eliminating patches invading along the Trans Canada highway (hwy 104), and monitoring the adjacent marshlands.
Jef Achenbach of Annapolis Royal assisted with field work in the Annapolis valley region. The development of a database was supported by the Federal Biodiversity Information Partnership.
I am sorry to add a very aggressive salt marsh grass, Spartina anglica C.E. Hubb. (English cordgrass) to the growing list of invasive plants in British Columbia. I discovered it in August 2003 while conducting intertidal habitat surveys on Roberts Bank (Vancouver, British Columbia) in the Fraser River estuary:
Spartina anglica is a naturally formed amphidiploid, derived from S. x townsendii H. & J. Groves, both originating from the hybridization of S. maritima (M.A. Curtis) Fern. (small cordgrass), indigenous to England and Europe, and S. alterniflora Loisel. (smooth cordgrass), indigenous to eastern North America (Gray et al. 1991; Barkworth 2003). The latter species is thought to have been introduced to England in the early 1800’s from shipping (Gary et al. 1991).
In the Pacific Northwest, Spartina anglica was introduced into Puget Sound in 1961 to Port Susan Bay, just south of Stanwood, Washington State, to be used for dyke stabilization and to provide forage for cattle (Hacker et al. 2001). The plants thrived and expanded to 2.7 ha in mid 1970’s. Spartina anglica was surveyed there in 1997 and had spread to 73 sites affecting 3,311 ha of marine intertidal habitat, equivalent to approximately 400 ha solid habitat. One of the heaviest infestations is in Willapa Bay where it covers approximately 2,000 ha and is spreading at a rate of 16 % annually. It appears to be transported to new areas by three pathways: nearshore currents, water birds, or ships (e.g. ballast water). The source or pathway for the Roberts Bank infestation is unknown. However, it now has a circumpolar distribution being recorded in over 130 sites around the world!
Spartina anglica is a very aggressive species that will spread over the mudflat, displacing existing habitat and moving upwards into natural salt marsh. Of particular concern in the Fraser estuary is the conversion of large, productive mudflats, which are rich in invertebrates used by shorebirds, waterfowl, and fish, to monotypic stands of cordgrass. Washington State has spent several millions of dollars and years trying to eradicate Spartina, using a range of approaches including manual labour, mechanical equipment, and chemical control, many with mixed success (Murphy 2003). Because the infestation in the Fraser estuary is in the early stages, estimated to have begun 3-5 years ago, aggressive management and removal may control further spreading and eliminate the need to use herbicides and more damaging eradication techniques.
Following discovery of the infestation on Roberts Bank, I contacted Vancouver Port Authority (VPA) and they agreed to sponsor a control program on Roberts Bank. In September, with the assistance of the Department of Fisheries and Oceans (DFO), seed heads were clipped and extent of the infestation was mapped using GPS. Data collected indicated plants averaged 1 m in height and clones were dense, over 800 stalks per square metre. In October, the Fraser Spartina Busters, comprised of 21 volunteers from VPA, DFO, Canadian Wildlife Service, Ducks Unlimited, Water Land and Air Protection, Tsawwassen First Nations, and Langley Environmental Partners Society, removed all but three clones from Roberts Bank and sent the plants to the Burnaby incinerator.
In December, an inventory was funded by Ducks Unlimited and the Greater Vancouver Regional District, Regional Parks, to conduct an inventory of the outer estuary. DFO provided the Canadian Coast Guard hovercraft to survey the Boundary Bay and the banks south of Sea Island. Foot surveys of the Sea Island and Iona Island shorelines followed. More S. anglica was found in Boundary Bay off Beach Grove and over a 3 km section of shoreline between 96th and 112th Streets.
Following two meetings in December, including participation by Washington State Spartina control agencies, DFO is leading an inter-agency initiative to develop an action program for the summer and fall of 2004 to remove the existing Spartina anglica from Boundary Bay and Roberts Bank. The initiative will involve DFO, CWS, DU, VPA, City of Delta and several NGO’s. The program will also involve annual follow-up surveys, inventory of shoreline areas, and preparation of fact sheets to increase awareness of the problem and assist in identifying the plant in the field. An outreach program has also been initiated to make presentations and provide information to interested parties, which have included the Vancouver Natural History Society and City of Delta.
Abstract. The number of studies dealing with plant invasions is increasing rapidly, but the accumulating body of knowledge has unfortunately also spawned increasing confusion about terminology. Invasions are a global phenomenon and comparison of geographically distant regions and their introduced biota is a crucially important methodological approach for elucidation of the determinants of invasiveness and invasibility. Comparative studies of alien floras p rovide substantial new insights to our understanding of general patterns of plant invasions. Such studies, using information in previously published floras and checklists, are fundamentally dependent on the quality of the assessment of particular species with respect to their taxonomic identity, time of immigration and invasion status. Three crucial decisions should be made when defining the status of a plant species in a given region: (1) whether the taxon is native or alien to that region (origin status); (2) what is its position in the invasion process, i.e., when was it introduced (residence status); and (3) what is the degree of its naturalization and possible invasion (invasion status). Standard floras differ hugely in their treatment of non-native species and those with appropriate categorization of alien species according to their status are rather rare. The present paper suggests definitions of terms associated with plant invasions and places these into the context of floras. Recommendations are outlined on how to deal with the issue of plant invasions in standard floras with the aim of contributing to a better understanding between taxonomists and ecologists and allowing more detailed comparative analyses of alien floras of various regions of the world.
The authors proposed the following hierarchy of alien plants:
The categories at each level are mutually exclusive with the exception of "cultivated" and "outside cultivation", and "weeds" and "transformers", respectively, which can overlap. Note that both "weeds" and "transformers" can be also native taxa.
[P.S. I prefer the term "edificators" for what the authors call "transformers". Those are plants that significantly change habitat conditions, e.g., Scotch broom, Cytisus scoparius L., in North America. - AC]
Does your expertise relate in any way to Canada's wild medicinal plants? A database providing information about people dealing in any way with any of Canada's approximately 1500 wild medicinal plant species is under construction at Agriculture & Agri-Food Canada. This information will be made available to the public. If your work relates to this subject, you are invited to complete one of the following on-line forms:
The excellence and thoroughness of Flora immediately demand it be placed on the reference shelf next to my two earlier favorite, all-purpose, hort encyclopedias: R.G. Turner, Jr. & E. Wasson (ed.)'s Botanica (1997, with CD-ROM; for review see R. Schmid, Taxon 47: 221-222; the 1999 3rd ed., 1020 pp., noticed in Taxon 49: 385) and C. Brickell & J.D. Zuk (ed.)'s The American Horticultural Society A-Z encyclopedia of garden plants (1996; see Taxon 49: 367; U.K. ed. as Royal Horticultural Society ..., 2003; as EGP below).
The comparison statistics are:
Flora hence outdoes both. It also has 101 color illustrations and 14 maps, and its CD-ROM actually has 11,489 still jpgs and 1245 animate jpgs. All books have the useful obligatory front matter on horticultural groups and cultivation, respectively, 22, 44, and 52 pages in the three works, but I regard such information as superfluous and am interested only in the accounts of taxa and the brief guide to the format of the book. The slipcase of Flora is nice but unwieldy; it makes a fine container for file folders.
Selecting at random five genera, Boykinia, Dianthus, Hordeum, Nepeta, and Rosmarinus, allows some comparison betwixt Botanica (pp. 150, 300, 450, 600, 801 for the genera), Flora, and EGP: all works note the family (most clearly in EGP, awkwardly in back matter in Botanica), lack nomenclatural authorities, give common names, bold cultivars, and have dimensions in English and metric units. They also have comparable descriptive accounts, with the inevitable discrepancies, particularly for size and hardiness zones (e.g., Rosmarinus officinalis is hardy in zone 6, minimum -23°C/-10°F, much beyond EGP's zone 8, minimum -12°C/10°F), and omissions (e.g., EGP not mentioning the potential invasiveness of Hordeum). Matters of cultivation are most detailed in EGP, which has three categories: cultivation, propagation, and pests and diseases. The cultivation category of Flora and Botanica subsumes propagation and, inconsistently and skimpily, pests and diseases (none of the books address petal blight of Camellia). No book lists which contributor/consultant (67 in the case of Flora) did the horticultural account, a standard feature in taxonomic works.
With such richness presented in Flora, quibbles are few: its blank endpapers cry out for information about symbols, hardiness zones, terms, and the like; its covers and spines lack volume designations; a bibliography is lacking. But these omissions are minor. By the way, the CD-ROM of Flora is excellent, much more comprehensive and user friendly than the one that came with Botanica--well, what do you expect, six years later?
Naturally Flora describes and illustrates many more taxa than the others, but Botanica and EGP often treat additional taxa. For instance, for the aforenoted five genera, respectively, Flora treats 1/17/2/9/1 species, EGP 4/31/2/9/1 species, and Botanica 1/14/3/6/1 species, with 12 species Nepeta treated collectively. Thus it is worthwhile to check all three books. While Flora is indispensable, and I am increasingly partial to it, all three works are really essential. To make room on my reference shelf for Flora, I displaced Hortus third (1976), now mostly superseded by M. Griffiths's Index of garden plants (1994; for review see R. Schmid, Taxon 43: 688).