| BEN |
| BOTANICAL ELECTRONIC NEWS |
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| ISSN 1188-603X |
| No. 276 November 15, 2001 | aceska@freenet.victoria.tc.ca | Victoria, B.C. |
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In Central Europe, Phalaris arundinacea L. is a highly competitive, dominant grass in sites with a high groundwater table, high amounts of nutrients, especially nitrogen, and a permeable (sandy or gravelly) substratum. Vertical and/or horizontal water movement in the rhizosphere favours the species.
In the past three decades P. arundinacea has expanded into alluvial grasslands alongside eutrophicated water courses, especially where hay cutting or grazing no longer occurs. In those conditions, its expansion into alluvial meadows was rapid (Conchou & Patou, 1987; Klimesova & Cizkova, 1996; Prach et al., 1996; Straskrabova et al., 1996). The species became a strong dominant in the 5 years following meadow abandonment, increasing its cover from less than 1% to approximately 40%. Intensive lateral vegetative spread by rhizomes ensured the expansion.
Studies show, however, that P. arundinacea is sensitive to regular cutting and Regular frequent cutting is the most effective way to control the species. In a compact sward that was experimentally cut three times a year, it was nearly eliminated after only 4 years (Straskrabova & Prach, 1998; Prach et al., 1999). In the Central-European climate, three cuts a year (early June, late July and late September) showed the best results, two cuts a year (June and August) were less effective, whereas one cut a year had no desirable effect.
Mechanical disturbance techniques such as scraping are not effective because the species readily regenerates from small rhizome fragments. P. arundinacea is also able to survive long-lasting flooding, therefore artificial impoundment is not an effective management strategy.
In conclusion, eutrophication and low or non-management are the main reasons that P. arundinacea has expanded into alluvial grasslands, however, regular and frequent cutting is an effective measure to prevent expansion and will control the species even under eutrophicated conditions.
References:
Extensive populations of Ammophila breviligulata Fern. (American beachgrass) were discovered during surveys of beach plant communities on the west coast of Vancouver Island, British Columbia between June and September 2001. This is the first report of A. breviligulata in British Columbia. (Voucher collections are deposited in the University of British Columbia herbarium [UBC] in Vancouver, B.C.) Ammophila breviligulata is a large, rhizomatous beach grass that functions as a sand-stabilizer in its native habitat. Together with Ammophila arenaria (L.) Link. (European beachgrass or marram grass) it has caused substantial changes to sand movement, beach morphology, and vegetation along sand beaches and adjacent dunes on western Vancouver Island.
In Clayoquot Sound, Ammophila breviligulata occurs in beaches of Pacific Rim National Park Reserve, Long Beach Unit (Wickaninnish Beach, Schooner Cove, Radar Beach) and south west Clayoquot Sound (Stubbs Island and Vargas Island). In its native range it occurs on beaches along the Atlantic coast from Newfoundland to North Carolina, as well as the Great Lakes (Kartesz, 1999). Introduced populations have been reported from California (Hickman, 1993; Kartesz, 1999), and Oregon and Washington (Seabloom and Wiedemann, 1994). In British Columbia, Ammophila breviligulata is found in two habitats:
Like A. arenaria, vigour of A. breviligulata declines and flowering ceases inland from the first beach ridge where sand movement is reduced. Seabloom and Wiedemann (1994) documented this pattern in beaches of Washington State.
Ammophila breviligulata is distinguished from A. arenaria by smaller ligules (1-3 mm versus 10-30 mm long in A. arenaria), wider and less inrolled leaves, longer flower spike (25-35 cm versus 15-25 cm long in A. arenaria), and scaly rather than puberulent leaf veins on the upper leaf surface (Hitchcock, 1950). Vegetative material may also be confused with Leymus mollis. However, leaves of Leymus mollis are typically wider (15-20 mm versus 5-15 mm long in A. breviligulata and are distinctly glaucous compared to yellowish green in A. breviligulata. As well, L. mollis generally has auricles and has puberulent rather than scaly leaf veins.
Based on the presence of Ammophila breviligulata in older beach vegetation on the west coast of Vancouver Island, it is unlikely that it was introduced recently. It may have been present since the first introduction of A. arenaria in 1940's on Stubbs Island in south Clayoquot Sound. Alternately, it may have dispersed from populations introduced in Oregon and Washington for shore stabilization. Seabloom and Wiedemann (1994) used the distinct transition between older A. arenaria communities and more recent A. breviligulata communities to establish the approximate date of invasion along the southern Washington coast. Ammophila breviligulata was first introduced on the Clatsop Peninsula in northern Oregon in 1935 and has invaded northward through the dispersal of rhizome fragments. However, although A. breviligulata is present from the Columbia River to the Olympic Peninsula, it is the dominant beach grass only within 75 km of the original introduction site. The dominance of A. breviligulata at several Vancouver Island beaches may indicate a second point of introduction in proximity to Clayoquot Sound.
Ammophila breviligulata appears to have been overlooked during previous botanical surveys in coastal British Columbia because of its superficial resemblance to either Leymus mollis or Ammophila arenaria, depending on vigour and whether flowering panicles were present. In particular, it was not noted in a comprehensive assessment of beach plant communities in Wickaninnish Beach in Pacific Rim National Park Reserve by Kuramoto (1965). How its presence might change management activities to control Ammophila species along beaches on the west coast of Vancouver Island is unknown. Seabloom and Wiedemann (1994) concluded that A. breviligulata and A. arenaria were ecologically similar and both depress native plant diversity in beach vegetation.
References:
Contact information:
Any questions or comments should be directed to Nick Page, Institute for Resources and Environment, University of British Columbia at [napage@interchange.ubc.ca]. Information or opinions on the potential ecological effects and control methods for Ammophila breviligulata are welcomed.
Corallorhiza maculata var. ozettensis Tisch is a newly described orchid from western Washington. It occurs in foggy rainforests bordering the Pacific coast of the north Olympic Peninsula. Unlike typical C. maculata, its flowers are consistently non-spotted, with a narrow, white labellum bearing two apical undulations and low, non-rugose basal lamellae.
Key to three varieties of Corallorhiza maculata (Raf.) Raf. in coastal Washington:
- 1.
- Labellum white at early anthesis (darkening with age), its lateral nerves usually simple; the margins of its central lobe sub-entire ............................ C. maculata var. ozettensis
- 1.
- Labellum usually white, spotted with purple, its lateral nerves often prominently branched; the central lobe distally crenate-undulate.
- 2.
- Central lobe of labellum distinctly expanded, its broadestdistal portion > 1.5 times wider than its base; labial apex broadly rounded to retuse ......... C. maculata var. occidentalis (Lindl.) Ames
- 2.
- Central lobe of labellum slightly if at all expanded, its broadest distal portion < 1.5 times wider than its base; labial apex narrowly rounded to acute ........................... C. maculata var. maculata
Corallorhiza maculata var. ozettensis grows in moist, foggy, very shady to moderately illuminated forests bordering the northwest coastline of the Olympic Peninsula. The collection sites, all within 300 m of the Pacific Ocean, are overstoried by mixture of Picea sitchensis, Thuja plicata, Tsuga heterophylla in the tree layer; Vaccinium alaskense, V. ovatum, V. parvifolium and Menziesia ferruginea in the shrub layer. The common herb associates are Blechnum spicant, Polystichum munitum, Maianthemum dilatatum, Tiarella trifoliata, Listera caurina, and L. cordata.
Plant presses constructed of yellow-cedar (Chamaecyparis nootkatensis) are for sale for $35 CDN + postage. Presses are standard size (12" x 18" = ca. 30 cm x 46 cm ), with 4 lateral and 6 horizontal slats that are nailed and glued for increased sturdiness. Included for your convenience are two 1" x 5ft. (ca. 2.5 cm x 1.5 m) nylon straps with plastic buckles. Cardboard is not provided. Yellow-cedar is noted for its durability, lightness and strength. The wood used for making the presses comes from top-quality off-cuts (e.g., from mouldings, boat-building materials, etc.).
For orders or more information, please contact Nick Golinski at plantpress@hotmail.com
This book presents a forest vegetation classification for the coniferous forests of temperate and boreal North America based on field data obtained during the travels of a group of Spanish vegetation scientists from Madrid, led by Salvador Rivas Martinezi. It is the second in a series of monographs by the Madrid working group on North American vegetation formations, the first being a work on the arid regions of the American Southwest and Mexican Sonora (Itinera geobotanica 10, 1997). Like the first monograph, the present volume is concerned primarily with obtaining a large-scale overview of climate and vegetation types.
One is introduced into the work by a comprehensive review of bioclimatology, the study of the relationship between climate and living things, and the premises of the worldwide bioclimatic classification. We are then led through an overview of terms and concepts in climatology, geobotany and biogeographic typology. This is followed by a complete biogeographic typology of North America, divided into sectors and subsectors.
The next part of the book delves into the vegetation of these sectors and subsectors. The methods discussion is brief and consists primarily of references used for identification and nomenclature and explanation of what is contained in the tables; it gives little insight into how associations and higher units were derived and how synonymies were decided. However, it can be concluded that the authors visited zonal vegetation types in the various bioclimatic sectors and subsectors and made vegetation releves, and put these together into tables largely on the basis of occurrence in the same region. There is little evidence of actual tablework with these releves and certainly no evidence of any replicable numerical work.
The authors proceed to describe the hierarchy of the new class Linnaeo americanae-Piceetea marianae (supplemented by five new forest classes in Itinera geobotanica 13: 349-352, 1999), and numerous new orders, alliances and associations. Most of these are described for the first time. Vegetation tables are presented for every unit (although Table 16 is missing).
Although the individual releves are likely quite representative of the various bioclimatic regions from which they were taken, the vegetation units which have been made out of them are oftentimes rather dubious. Phytosociological tables are often comprised of only few releves from widely scattered areas, with little in common except physiognomy. One example is Table 63, made up of 6 releves from 5 states and provinces, an area the size of western Europe. Some new associations are based on only two releves, and often from very restricted areas. The association Oplopanaco-Alnetum rubrae, for instance, is based on two releves (Table 34) gathered a few kilometers from each other in northern British Columbia. Table 31 is also an example of a table where all releves are gathered from within a few kilometers of each other. This is not necessarily illegitimate in itself, but it does give cause to reflect on the scope of the book. For the purposes of comparison, it is useful to point out that the number of published releves presented in this book (about 450) divided by the size of the study area (an estimated 12,000,000 sq. km) would translate to a density of one releve every 25,000 sq. km, or about 20 for the area of Spain.
Some of the tables are so unconvincing they actually serve to undermine the units which they are meant to demonstrate. Table 39, for instance, is a brief synoptic table of two alliances, Piceo-Abietion bifoliae and Pino-Pseudotsugion glaucae. Our attention is drawn to the rather empty box of alliance character taxa for the former. This group of ecologically unrelated species has no diagnostic value and obviously does not represent a group of character species by any definition.
Another unfortunate distraction for the floristically inclined are the disturbingly numerous taxonomic misidentifications and simply impossible species. Examples include, but are by no means limited to, Brachypodium sylvaticum, given in many tables, which is not found in northwestern North American forests, Vancouveria hexandra, a conspicuous plant reported from the botanically well-known Goldstream Provincial Park on Vancouver Island (Table 19), which would be new for Canada, and Aquilegia coerulea, a plant of talus in the central Rocky Mountains, reported from forests of Klickitat County Washington (Table 20). Furthermore, species lists for well-known communities which typically have 45-50 vascular plant species per releve have only 15-20 listed. The listing of Bryophyta gen. et sp. pl. in numerous tables (esp. Tables 10-12 and 67-69) is inexcusable.
Some clarification on the methods for synonymization of syntaxa would have been useful. Without this, lists of plant community synonyms appear rather arbitrary. For instance, an order of western montane forests first described by V.J. Krajina is listed as a synonym of the quite different order of eastern boreal forests Gaultherio-Piceetalia. The order Betuletalia pumilae-glanduliferae, described by S. Kojima (Phytocoenologia 14: 1-17, 1986) for mire communities in Banff National Park, is subsumed under the new and completely unrelated subarctic order Ledo decumbentis-Betuletalia glandulosae.
A number of inconsistencies in the tables and text could also cause confusion. As one example, in Table 36 (Alno tenuifoliae-Populetum trichocarpae), releve 1 is designated as the type releve, but in the list of releves provided at the end, releve 3 is given as the type. To further confuse things, the floristic composition of the type releve listed in the text does not correspond to the same releve in the table. Furthermore, constancies are also commonly miscalculated in the tables.
One of the most disheartening aspects of not only the present book, but also the authors' previous work on North American deserts, is the virtual disregard for the vast amount of vegetation research which has taken place in the region under consideration, including basic descriptive community classification. Literally thousands of pages of literature, basic descriptions and ecological and floristic characterizations in the form of published articles, theses and technical reports are completely disregarded or afforded only passing mention - or subsumed as synonyms under the various "newly" described associations, alliances and orders. It is not that Rivas-Martínez and his colleagues were entirely unaware of this research either, as they cite some of it and synonymize names liberally. It is untenable to ignore previous works (phytosociological groupings and synecological observations) only because the names their authors used did not comply with the International Code of Phytosociological Nomenclature.
The Braun-Blanquet method applied in this work has been highly successful in the study of European vegetation and its application is spreading. In North America it is an obvious way to standardize the study of vegetation and unify the results of many diverse, endemic classification systems. Unfortunately, the publication by Rivas-Martinez et al. does not help this effort.
[Note: This book was also reviewed by Dieter Mueller Dombois (Phytocoenologia 30: 269-271, 2000) and by Michael Barbour (Journal for Vegetation Science 12: 593-594, 2001).]