|BOTANICAL ELECTRONIC NEWS|
|No. 315 October 23, email@example.com||Victoria, B.C.|
BEN is proud to sponsor the following symposium:
We are pleased to invite you to attend the 2004 meeting of the International Association of Vegetation Science in Kailua-Kona, Hawaii Island, Hawaii, USA. The meeting theme "Landscape Change and Ecosystem Disturbance: Islands and Continents" will provide an ample umbrella for contributed papers, posters, and special sessions on vegetation theory, methods, observations, experiments and management. Field trips before, during and after the conference are special, rare opportunities to see Hawaii's beautiful endangered plant communities with expert guides.
For more details see http://conference.uhh.hawaii.edu/iavs2004.info.htm
We look forward to seeing you in Hawaii in 2004!
Julie S. Denslow (US Forest Service)
Dieter Mueller-Dombois (University of Hawaii)
How would anyone know that a solid stand of sedge was entirely alien? After all, there are relatively few invasive alien sedges, and many native sedges do form more or less monospecific stands. Furthermore how many field biologists can recognize sedges? Even experts are less likely to recognize a species that is unknown in their region and consequently not covered in regional literature. European Lake Sedge (also called Lesser Pond Sedge, Carex acutiformis Ehrh.) is a case in point. It was first noticed in Canada when a specimen originally misidentified as Carex aquatilis was correctly identified by sedge expert A.A. Reznicek (Univ. of Michigan). This plant was collected in the Stony Swamp near Ottawa on 10 June 1987 and again at the same location on 6 June 1989 (specimens in the Agriculture and Agri-Food Canada herbarium, Central Experimental Farm, Ottawa).
A rare introduction in North America, European Lake Sedge was one of a number of invasive aliens of the Ottawa District highlighted during the Ottawa workshop on invasive species hosted by the Ottawa Stewardship Council in May 2003. It was highlighted as a serious invasive from Europe that is unique in Canada to the Ottawa District. It is also known from six states in the northeastern U.S. (Reznicek & Catling 2002). During the workshop one of the important points that emerged was that people need information in order to participate in the monitoring and management of invasive alien plants. The most needed information is how to identify the invasive plant and this is particularly important for species that may be readily mistaken for natives. Next is the location and how much of it there is as well as biological information on spread and dominance. This kind of information has been requested on several recent occasions for the European Lake Sedge at Ottawa. Since it is an alien that could be easily overlooked, and may even now be more prevalent than we realize, the following information may be useful anywhere in North America.
Among the large group of sedges (genus Carex), European Lake Sedge is distinctive in its possession of more than one spike on a stem, 3 stigmatic branches, and 3-sided fruits within a non-hairy sac (called the perigynium) and a persistent style at the top of the fruit. The perigynia are coarsely 12-18-nerved, 3-4.5 mm long, with a beak 0.3-0.6 mm long and teeth 0.2 mm long. The upper spikes are either entirely staminate, or pistillate at the base and staminate above. European Lake Sedge differs from other members of its section Paludosae in its combination of smooth (instead of hairy) perigynia, leaves moderately broad, 5.5-15 mm wide (instead of less than 5 mm wide) and perigynia relatively short being 3-4.5 mm long (instead of longer).
Of course sedges are notoriously difficult to identify, but some are easier than others. European Lake Sedge is relatively easily identified if one knows what to look for. At close range, it bears a general resemblance to only a few native species. It differs from the Beaked Sedges (Carex rostrata Stokes and Carex utriculata Boott) in having perigynia with much shorter beaks (less than 1/4 the length of the perigynia), and the leaves are plicate (M-shaped rather than V-shaped in cross-section) and often only obscurely septate-nodulose (instead of strongly so). This latter term refers to partitions in the tissue that become raised bumps when the tissue dries out or is compressed). In northeastern North America, European Lake Sedge most closely resembles Tussock Sedge (Carex stricta Lam.) and Aquatic Sedge (Carex aquatilis Wahlenb.) but differs markedly from both of these in having strongly nerved (instead of nerve-less) perigynia (the sac enclosing the fruit of a sedge), three-parted stigmas and three-sided fruits called achenes (instead of a 2-parted stigmas and a two-sided, lenticular fruits). At a distance it also resembles a stand of Lake-bank Sedge (Carex lacustris Willd.). It differs from Lake-bank Sedge, and from other species in its section Paludosae, in its hairless and relatively short perigynia, and moderately broad leaves (5.5-15 mm wide).
Although it appears that it is not yet spreading aggressively in North America, it clearly has the potential to be a very serious invasive and its general resemblance to the native species could allow it to go undetected long enough to become increasingly well established and to initiate a stage of much more rapid spread. Identification and control are thus important issues. Already it may have been overlooked to a degree. Another very helpful clue to recognizing this invasive on the landscape is the fact that the leaves remain green long after the first frost and later in the fall than those of many native sedges. This is a general characteristic of plants of European origin that is shared with other northeastern invasives such as Glossy Buckthorn (Frangula alnus Miller) and European Weeping Birch (Betula pendula Roth).
The 1989 specimen label notes that this alien species "was dominating several acres of moist, open area." In 2003 we visited the site to further evaluate its dominance. It dominated an area of approximately 6 acres of moist open marsh with scattered trees of Tamarack, Eastern White Cedar, White Birch, and American Elm. Along a 3 m wide transect 215 m in length, representing 645 m2 quadrats, the sedge had a frequency of 100% and « of its surface area (cover) was 100 to 500 % of the surface area of each quadrat, with an approximate average of 200%. The only other species present are listed in Table 1. These are all native and none contributes more than a fraction of a percentage of the cover. The very extreme dominance of European Lake Sedge is clear from the frequency and cover values of the native species. A general survey confirmed that the sampled area was representative of the 6 acre stand. In general native species were either trees or confined to more recent mounds produced by ants. Ferns (Table 1) were often present on new currently used ant mounds, and Cinnamon Fern (Osmunda cinnamomea L.) appeared to be able to maintain a place on these mounds and possibly to resist encroachment by the sedge as a result of its extensive and dense rhizome development.
An adjacent area of similar elevation and tree cover on the edge of the stand has a diverse natural plant association with many co-dominants including: Athyrium filix-femina (L.) Mertens var. angustum (Willdenow) G. Lawson (Northern Lady Fern), Boehmeria cylindrica (L.) Sw. (False Nettle), Calamagrostis canadensis (Michx.) P. Beauv. (Blue-joint Grass), Carex spp. (Sedges), Cornus sericea L. - Red-osier Dogwood), Onoclea sensibilis L. (Sensitive Fern), Parthenocissus quinquefolia (L.) Planchon ex DC. (Five-leaved Virginia Creeper), Solidago canadensis L. (Canada Goldenrod), Solidago rugosa Aiton subsp. rugosa (Rough Goldenrod), Symphyotrichum punicem (L.) Löve & Löve (Aster puniceus L. var. puniceus, Purple-stemmed Aster), and Thelypteris palustris Schott var. pubescens (Lawson) Fernald (Marsh Fern).
The native species present in the stand of European Lake Sedge are also present in this adjacent diverse native plant association and are likely remnants of this association which was probably displaced by the alien sedge. At least it seems likely that this diverse native association would be present were it not for the dominance of the alien sedge.
Although much of the area it dominates is relatively uniform as described above, the European Lake Sedge at the Stony Swamp site has a remarkable ecological amplitude. It grows in hummocks around open water up to 1 m deep. Here the rhizomes grow out into the water and extend the hummock. There is some evidence that European Lake Sedge may be controlled in wetlands by reduction in water level (Kazda 1995), but at the Stony Swamp site it grows in some relatively dry semi-open areas where the vegetation is dominated by an old field association of Daucus carota L. (Wild Carrot) and Poa compressa L. (Canada Blue Grass). In these areas the sedge is 100% cover or less, but still dominant up to the edge of the more diverse association.
European Lake Sedge is unusual among sedges in its high canopy and large amount of leaf area (Aerts & DeCaluwe 1994). This allows both photosynthetic carbon gain and suppression of other species in the competition for light. It is a highly productive species in its native range and is characteristic of eutrophic wetlands. Its leaf litter decomposes more slowly than that of other species of sedge (Aerts and DeCauwe 1997). The litter immobilizes more N and P for longer periods than the litter of other species (Corona and Verhoeven 1999). The characteristic dense cover of the current year growth as well as the dense accumulation of litter forming a dense subcanopy were characteristic of the Stony Swamp population. The extreme dominance of this introduced sedge may be attributable to a combination of successful competition for nutrients and competition for light as a result of both dense green cover and smothering by persist ing dead leaves from the previous year. The effect of litter accumulation may be greater in base-poor waters (more acid waters over granite or sandstone) due to slower cellulose decay than occurs in base-rich waters (Verhoeven & Arts 1992).
It seems most likely that European Lake Sedge arrived at the Ottawa site in hay from Europe. A number of farms existed in the immediate vicinity which may have introduced hay from Europe. Another more frequent introduced sedge, Carex flacca Schreb. (HEATH SEDGE) occurs nearby in drier pasturelands with many other introduced species. The Stony Swamp area is one of the botanically richest areas of the Ottawa district (Brunton 1982). Substrates include limestone, sandstone and glacial till. The population of European Lake Sedge is on top of a rolling sandstone-capped plateau. It is fruiting abundantly and it appears to be capable of spread of perigynia by both adhesion to a variety of mammals such as beaver and muskrat and ingestion by waterfowl. Since it occurs along a major road in the ditch and along the ditch banks, another potential method of spread is transport of root masses and rhizomes by road maintenance vehicles.
TABLE 1. Species names followed by percentage frequency and percentage cover of 12 vascular plants recorded in 645 m2 plots along a transect through an open wetland dominated by European Lake Sedge (Carex acutiformis Ehrh).
Carex acutiformis Ehrh., European Lake Sedge, 100.0000, 200.0000; Parthenocissus quinquefolia (L.) Planchon ex DC., Five-leaved Virginia Creeper, 0.0108, 0.0010; Phalaris arundinacea L., Reed Canary Grass, 0.0170, 0.0079; Ulmus americana L., White Elm, 0.0015, 0.0077; Betula papyrifera Marshall, White Birch, 0.0015, 0.0077; Epilobium sp., Willowherb , 0.0015, 0.0015; Cornus sericea L., Red-osier Dogwood, 0.0046, 0.0004; Onoclea sensibilis L., Sensitive Fern, 0.0003, 0.0003; Thelypteris palustris Schott var. pubescens (Lawson) Fernald, Marsh Fern, 0.0124, 0.0012; Athyrium filix-femina (L.) Mertens var. angustum (Willdenow) G. Lawson, Northern Lady Fern, 0.0003, 0.0010; Dryopteris cristata (L.) A. Gray, Crested Wood Fern, 0.0015, 0.0001; Sambucus canadensis L., Common Elderberry, 0.0015, 0.0010.
In 2000, when we drove from Ontario to the CARCNet [Canadian Amphibian and Reptile Conservation Network] meetings in Pentic- ton, we GPS'd Typha angustifolia L. and Phragmites communis (Cav.) Trin. ex Steud. along roadsides all across the country. Among the results was a complete absence of Typha angustifolia in the Okanagan, and a nearly complete absence of Phragmites.
The exceptions were the two sites detailed below, which are separated by less than a kilometre. These were the typical invasive-type Phragmites, which looked like they were spread- ing as rapidly as if they had been on the outskirts of Montreal or Syracuse.
See http://www.invasiveplants.net/phragmites/phrag/natint.htm for a discussion of the differences between the invasive and native Phragmites. [For more information, see also BEN # 310 and BEN # 284. - AC] I suggest that anyone concerned with the native flora of the Okanagan look into the identity of these stands, and the possibility of action against them while they're still relatively confined.
Phragmites australis. codominant herb, in fruit, specimen. 2000/219/bc Canada: British Columbia: : Highway 97, MAP: 82E/4, UTM 11U 313557 5440620. 49.09202N 119.55497W 18 September 2000 Collected by: Frederick W. Schueler, Aleta Karstad, & Jennifer H. Schueler, Karstad family Field#: 2000/219/bc Habitat: disturbed roadside shore of small Scirpus-bordered lake; big stands for several 100 m S of here, & a few to the N. This is from a stand where the lake comes closest to the road. After not seeing this species once along the TransCanada Hwy from central Manitoba to Westbank, it's striking to see it rambling 'invasively' over disturbed ground here, as if this were the outskirts of Montreal or Syracuse.
Phragmites australis. 1 stand, specimen. 2000/226/aa Canada: British Columbia: Okanagan R, at ecological reserve. MAP: 82E/4, UTM 11U 314453 5440990. 49.09561N 119.54288W 25 September 2000 Collected: Frederick W. Schueler, CARCNET field trip Field#: 2000/226/aa Habitat: channelized river in sagebrush desert; WAYPT/104, single stand on inland side of dike along river. There were more stands in a circular marsh farther west.
Note: Waypoints determined by: F.W.Schueler; Site accuracy: 100m Garmin45 Coordinates from: GPS:L/L-WGS84,UTM-NAD27Canada; EOBase
An illustration with Pacific Yew tree in the centre, an owl in the branches and other animals as well as arrows indicating ecological cycles appeared no later than 1998. We have tried to locate this image but have not been able to do so. We recall having seen it in a popular article about the value of biodiver- sity. If anyone can help us to locate this image and its source, we would very much appreciate it. The reward for the first person to reply with information leading to our locating the image and its source is a free copy (English or French) of the book "Canadian Medicinal Crops" published by NRC press. The picture of Pacific Yew in the book on page 153 came from the ecological diagram we seek. The tree alone also accompanies a description at http://www.fs.fed.us/ipnf/eco/yourforest/trees/yew.html
When living in a part of the country where the leaves start to fall at the end of August and do not begin to reappear until the end of April or early May, identifying most plants in all their leafy glory must be crammed into a few short summer months. Consequently, being able to identify some of the plants during most of the remaining months is a definite asset - especially for people involved in resource management activities like forestry, wildlife habitat assessment and so on. For college students, whose school days coincide almost exactly with the leafless months, learning how to identify deciduous plants in winter dormancy (at least those that show above the snow) is a must - there is not much choice!
This is a guide to the winter identification of not only deciduous trees and shrubs, but also evergreen coniferous trees and evergreen flowering shrubs commonly found in northwestern British Columbia. Most species included here are also found elsewhere in the province.
The keys and identifying features used in this guide are designed with a minimum of technical jargon and using simple diagnostic features that are easy to see in the field. Pen and ink illustrations for each species highlight their key identifying field characteristics.
Beautiful pen and ink drawings (black and white) done by Evi for each of the species for which there is a key.
Keys to: 19 species of conifers, 4 species of deciduous trees, 32 species of deciduous shrubs, and 7 species to evergreen shrubs. Contains also a list of other species (15) found in the north and where to find them, glossary, references, index.
All species described with key field identification features, mainly focussing on twigs (what can be seen in winter), but also some other features (e.g. bark in trees) and some interesting natural history notes. Illustrations on page facing the description are annotated with the most important identifying features.
Lone Pine Publishing publications can be ordered at the following toll-free phone number: 1-800-661-9017
I am establishing my business as a consulting systematic botanist (morphology) and still require some equipment. Boom mounted microscopes are amazingly expensive, so if anyone has a used one for sale, I would be willing to pay a reasonable price for it. Even the boom alone would be useful. Also, with less urgency, I would like to buy a used herbarium cabinet and am willing to pick it up.
If anyone is clearing out histological equipment, please contact me since I might be interested in buying part or all of it.
I am good with computers, statistics and gory details. If you want more information, reply to firstname.lastname@example.org or phone the number below. There is an answering machine. My daily charge is highly competitive.