ABSTRACTS FROM 1988 MEETING IN NARAMATA

The BOTANY BC Meeting in Naramata in May was a hugh success. Sincere thanks to the organizers: Karen Yearsley, Bob Ogilvie, Carol Thompson, Andrew Harcombe and Allen Banner. Tony Hamilton was a great help at registration. The following abstracts were received (most of the presentations at the meetings):

EFFECT OF SPATIAL ARRANGEMENT ON DEER USE OF HABITATS -- Laurie L. Kremsater, Faculty of Forestry, U.B.C.

Deer use of forage, cover, and border habitats was evaluated to judge the importance of spatial arrangement of habitats to black-tailed deer (Odocoileus hemionus columbianus). Deer home ranges consisted of a wide variety of forage and cover combinations. Cover habitats constituted a larger portion of home ranges in winter than in summer. Areas of intense use were characterized by greater proportions of cover habitat than areas of less intense use. Use of forage and cover habitats was compared to availability of those habitats within deer home ranges. Use was as expected from availability. Because use followed availability, but availability change seasonally and with intensity of deer use, any selection of broad forage and cover habitats appeared to occur during location of the home range, not after its establishment.

Availability of border habitat within deer home ranges depended on the width assigned to the border. An average of approximately 40% of home range areas occurred within 30 m of a forest/clearcut boundary. An average of 65% of home range areas occurred within 90 m of those boundaries. Availability of border habitat was greater in winter than in summer, particularly for borders between second-growth and old-growth forests. Areas of intense deer use had more available border habitat than areas of less intense use. Use of border habitats was generally as expected from availability. Both resident and migratory deer appeared to respond similarly to borders. Because use of borders closely followed availability but availability changed seasonally and with intensity of deer use, it appeared that most selection for border habitat occurred during the location of home ranges, not within the home range. Comparisons of actual use of borders to expected use based on the habitat mosaic surrounding the home range suggests that selection for borders did indeed occur during home range location.

TOXIC ELEMENTS IN PLANTS -- W. Majak, Agriculture Canada Research Station, Kamloops, B.C. V2B 8A9

Estimates by a U.S. economist indicate that poisonous plants cause a $200,000,000 annual loss to the livestock industry. Current research on three types of toxic constituents of rangeland plants will be reviewed. The discussion will consider the impact of nitrotoxins, cyanogenic glycosides and alkaloids on ruminants.

Columbia milkvetch (Astragalus miser var. serotinus) also known as timber milkvetch is widely distributed in the southern Interior of B.C. This native legume synthesizes large quantities of miserotoxin, a nitrotoxin that causes acute and chronic poisoning in cattle and sheep. Earlier studies on the potential toxicity of timber milkvetch reported toxin concentrations per unit of plant dry matter. Recently it has been possible to determine the total accumulation of miserotoxin per plant. The accumulation of the toxin parallels the growth cycle of the plant with a higher level of the toxin associated with a larger biomass. The availability of the toxin increases with advancing stages of growth and therefore the hazard to grazing livestock may also increase especially during the pod stage of growth before the onset of senescence. The microbial hydrolysis of miserotoxin to 3-nitropropanol in the rumen and the lethal synthesis of 3-nitropropionic acid through the action of alcohol dehydrogenase will be reviewed. In addition, current studies on the detoxification of 3-nitropropanol by rumen bacteria will be discussed.

The saskatoon shrub (Amelanchier alnifolia) is a significant component of the mule deer's diet. However, the shrub synthesizes the cyanogenic glycoside prunasin, which is rapidly converted to cyanide by rumen microorganisms. Average prunasin concentrations in newly initiated leaves of A. alnifolia var. cusickii were threefold greater than in A. alnifolia var. alnifolia. This varietal difference may well explain the differential toxicity of the shrub and why very low levels of cyanide were observed in vivo when the shrub was fed to cattle in earlier studies. Diurnal changes in rates of degradation of cyanogenic glycosides in bovine rumen fluid will also be examined including the effects of rumen pH and forage quality.

Recent studies on the teratogenic alkaloid, anagyrine, from Lupinus polyphyllus, will be discussed. Larkspur toxicity will be reviewed with special emphasis on the neurotoxic alkaloid from Delphinium nuttallianum.

EFFECTS OF INTRODUCING DEER ON THE QUEEN CHARLOTTE ISLANDS -- H. Roemer, Ecological Reserves, Ministry of Parks, Victoria

Coast black tail deer were introduced to the Queen Charlotte Islands in the early 1900s and, in the absence of natural predators, have increased and spread quickly. No written accounts of their impact on the vegetation were available until the late seventies when ecologists began studying the forest vegetation (Pojar et al., Lewis, Roemer, unpublished). Moss-draped old-growth forests with solid moss ground covers, but no shrub and herb layers were considered a characteristic of the Charlottes.

However, detailed study of forest composition on the Queen Charlotte Islands revealed that the species forming shrub and herb layers elsewhere on the outer coast were all present, but in a greatly reduced state. Direct observation of grazing and browsing evidence led to the conclusion that these species must have been dominant in a pre-deer era. The most dramatic impact was observed on Vaccinium species, salal, salmonberry, and devil's club in the shrub layers and on deer fern, sword fern, oak fern, skunk cabbage and others in the herb layer. On some islands, vigorous growth of shrubs, ferns and herbs is now only found in places inaccessible to deer, such as cliffs, or perched high on tall stumps. Tree regeneration was also severely affected. Western redcedar was browsed most, followed by yellow-cedar and Sitka spruce.

Confirmation that shrub layers were once very luxuriant is found in the descriptions of early foresters (Gregg 1923, Hopkinson 1931, Hall 1937).

Comparative vegetation tables by Pojar and Banner (1982) of climax forests and alluvial forests with their mainland counterparts show much lower mean covers in shrubs and herbs for the Queen Charlotte samples.

The long-range impacts of predator-free deer populations on the Queen Charlotte Islands will be the gradual loss of western redcedar from the forests and changes from cedar-spruce to spruce-hemlock or even pure hemlock types. Elimination of vascular undergrowth will gradually proceed from the smaller and southern islands to the larger islands, including Graham Island. Starvation of deer in unusually cold or snowy winters may become more common.

THE INTERACTIONS BETWEEN CATTLE AND MOUNTAIN SHEEP AS MEDIATED BY STRUCTURE AND FUNCTION OF BUNCHGRASS VEGETATION IN BRITISH COLUMBIA -- Dr. Michael D. Pitt, Associate Professor, Plant Science (Rangeland Ecology), University of British Columbia

Foraging habits of California bighorn sheep (Ovis canadensis californiana) in steppe vegetation of southern British Columbia were investigated between 1977 and 1983. Seventy-nine taxa occurred in the bighorn sheep diet, including all grasses, sedges, and shrubs, plus 47 of 58 forbs and bryophytes. Diet diversity peaked in spring, following lows during winter. Forbs comprised the greatest number of taxa in the diet throughout the grazing year; grass, however, averaged 66.6% of the total diet, compared to 19.0 and 14.4% for forbs and browse, respectively.

Bighorn sheep diet correlated most with plant cover rather than with forage quality, and varied according to seasonal availability of palatable forages within four phenological groups, including Spring Ephemeral, Summer Dormant, Summer Quiescent, and Protracted Growth taxa. The eight Spring Ephemerals consisted entirely of forbs, seven of which were perennial. Summer Dormant species similarly consisted primarily of forbs (20 of 36 species), but also included the largest number (10) of annual grasses and forbs. The 27 Summer Quiescent plants comprised 11 perennial forbs, plus eight of the nine perennial grasses which occurred on the study site. The Protracted Growth phenological group contained four deeply-rooted shrubs that continued growth throughout the entire frost-free period. These 4 groups attained phenological stages at different times throughout the calendar year, thereby providing pulses in peak nutrient and biomass production.

Based upon selection indices, preferred bighorn sheep forages generally included forbs and smaller grasses. Optimal habitat for bighorn sheep, therefore, likely differs from optimal habitat for domestic cattle, which generally graze preferentially on larger, perennial grasses. Controlled cattle grazing, therefore, may occasionally enhance California bighorn sheep habitat by promoting plant taxa and phenological groups preferred by bighorn sheep. Pasture sage (Artemisia frigida) and buckwheat (Eriogonum spp.) increase in response to cattle grazing, and are both preferred by California bighorn sheep. Spring Ephemerals, consisting of forbs preferred by bighorn sheep, initiated growth early in March and typically flowered by mid-May. Assuming appropriate cattle stocking rates, and spring turnout dates, Spring Ephemerals are unlikely to be seriously reduced by cattle grazing. Negative impacts of cattle grazing are most likely to occur by reducing Summer Dormant taxa, including some forbs grazed preferentially by bighorn sheep, and by reducing Summer Quiescent species, including some larger perennial grasses which provide palatable, nutritious fall regrowth.

Use of cattle to enhance California bighorn sheep habitat likely has restricted opportunities. In most cases, coordinated management of cattle and mountain sheep will focus on appropriate cattle stocking rates and seasons of grazing which minimize negative aspects of livestock grazing. Specific management objectives are achieved more readily by capitalizing upon the positive aspects of cattle/California bighorn sheep interactions, as mediated by the structure and function of bunchgrass vegetation.

ALPINE FLORISTIC STUDIES IN BRITISH COLUMBIA: AN OVERVIEW -- R.T. Ogilvie, Botany Division, Royal British Columbia Museum, Victoria, B.C., May, 1988.

Within the great physiographic diversity of British Columbia there are over 50 major mountain ranges. Because of their vastness, their difficult accessibility, and the brief field season for research, detailed inventory of the alpine flora has progressed slowly.

The first alpine collections were made two centuries ago in the mountains of Vancouver and Queen Charlotte Islands, and the Coast Ranges, by Archibald Menzies and Thaddeus Haenke. In the early 19th century David Douglas and the Palliser Expedition made limited alpine collections in south-central and southeastern B.C. The peak of activity in pioneer alpine plant collecting was at the turn of this century, with the work of John and James Macoun, G.M. Dawson, and J.B. Tyrrell, in the Rocky, Selkirk, Cascade, and Vancouver Island Mountains.

We review the mountain ranges for which there are alpine plant collections, species lists, or published floristic records. Adequate floristic inventories are available for the St. Elias-Alsek Ranges, the Queen Charlotte and Vancouver Islands Mountains, a few of the extreme southern Coast Mountains, parts of the Cascade Mountains, the Okanagan Highland, the central Selkirks, and the southern Rocky Mountains. But floristic information is lacking or meagre for most of the Coast Mountains, the mountains of the Interior Plateaus, the northern Rocky Mountains, and much of the Columbia Mountains.

At present we can only make gross, qualitative comparisons of the alpine floras of different mountain ranges. We do not have the basic data for quantitative comparisons of species-diversity, or for calculating index of similarity values of different mountain ranges.

Floristic inventories are essential for knowledge of our rare and endangered alpine species and their conservation. There are approximately 175 rare alpine taxa in British Columbia. Certain mountain ranges are known to have high concentrations of rare taxa: the Queen Charlotte and Vancouver Island Mountains, the Cascade Mountains, the St. Elias and northern Coast Mountains, and the southern Rocky Mountains. Factors potentially endangering the rare alpine flora are: mining activities, recreation facilities and activities, and tele-transmission installations. In addition to basic floristic inventories, for a rational conservation program for the endangered alpine flora, we need autecological and population biology studies on the species, and long-term monitoring of the plants and their habitats.

ALPINE AND SUBALPINE VEGETATION OF BRITISH COLUMBIA -- Evelyn Hamilton, Ministry of Forests, Victoria, B.C.

Alpine and subalpine vegetation in British Columbia typically consists of lichens, rosette plants and dwarf shrub vegetation on the ridges, grasses on submesic sites, heaths and forbs on the moister midslope sites and sedge dominated snowbeds. Duration of snowcover and moisture are important determinants of plant community distribution. In the higher snowfall Coast Mountains, dwarf shrubs including Dryas octopetala, Salix nivalis, S. cascadensis, and Arctostaphylos uva-ursi are common on the ridges and heaths including Phyllodoce spp. and Cassiope mertensiana prevail on the midslope sites with Valeriana sitchensis and Lupinus latifolia meadows in seepage sites and Carex nigricans snowbeds in depressions. In the rainshadow of the Coast Mountains, Dryas octopetala, Salix spp. and Arctostaphylos uva-ursi are common on drier sites, and grasses including Festuca spp. and Koeleria cristata are common along with Salix brachyphylla and S. barclayi on mesic sites. In the higher rainfall areas of the central interior, in the Columbia and Rocky Mountains, the vegetation is more similar to that of the coast, with heaths and forb meadows in the mesic sites, Salix arctica and Artemisia norvegica on the upper slopes and Dryas, Cassiope tetragona and Kobresia myosuroides on the ridges. In the northern part of the province grasses including Festuca altaica, Elymus innovatus and Kobresia myosuroides, willows and birches predominate.

ALPINE FLORA AND PHYTOGEOGRAPHY OF IDAHO -- Douglas M. Henderson and Robert Moseley, Department of Biological Sciences, University of Idaho, Moscow, Idaho and The Nature Conservancy, Moscow, Idaho, 83843.

Of the more than 20 mountain ranges in Idaho, 11 have sufficient topographic relief to support a moderate to well developed upper timberline. These ranges occur mainly in east central Idaho. All 11 have elevations in excess of 2900 m and seven of them exceed 3300 m. The majority of alpine plant taxa occur in these latter seven ranges. Of the estimated 2,665 vascular plant species of Idaho, 327 (12.3%) are known from alpine habitats, with 127 (38.8%) apparently restricted to alpine habitats and 200 (61.2%) also occur in subalpine (or lower) regions. Approximately 66 species (20%) are apparently restricted by substrate with 36 (11%) encountered only on carbonates, 25 (7.6%) apparently excluded from carbonates, and 261 (80%) are bodenvags. Preliminary data suggest that 111 species (34%) have phytogeographic affinities in the Western North American Cordillera, 49 (15%) are circumpolar, 35 (10.8%) are Rocky Mountain (Canadian and US), 36 (11%) are North American Arctic-Alpine or Boreal-Montane, 29 (9%) are regional endemics (mainly east-central Idaho-adjacent Montana), 12 (3.7%) are state endemics, of which 8 (2.5%) are narrow endemics. The remaining taxa are distributed among seven additional phytogeographic affinities. Idaho's alpine flora has fewer circumpolar taxa than other US Rocky Mountain alpines but more than the alpine of the northern Great Basin and the Sierra. With regional and state endemics combined (ca. 13%), Idaho's alpine appears to be higher in endemics than might be predicted.

HIGHER POSTGLACIAL ALPINE TIMBERLINES IN THE EASTERN COAST RANGES OF BRITISH COLUMBIA -- Rolf W. Mathewes, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6.

During the summer of 1987, a "buried forest" above the present forest limit was investigated by the author and Dr. J.J. Clague of the Geological Survey of Canada. Castle Peak Cirque is located in the coast/interior transition east of the Lillooet Icefields. Wood and whole logs buried by colluvial deposits are now being exposed by erosion. Ten wood samples were identified as either Pinus albicaulis or Abies lasiocarpa. Five samples were submitted for radiocarbon dating, in order to test the theory of an early Holocene period of maximum warmth. Four dates have been received so far, and all fall between 8000 and 9000 years BP. Growth rings were compared to krummholz and upper subalpine trees in the area, and confirm that early Holocene conditions for growth were better than those of today. Based on estimates of treeline shifts for whitebark pine of ca. 200 m above present, summer temperatures were estimated to be about 1.3 degrees C warmer than today.

Pollen analytical research on peaty deposits above the forest bed support the inference of an elevational rise in the forest-tundra ecotone during the early Holocene.

AQUATICS PLANTS OF BRITISH COLUMBIA -- Adolf Ceska and Oldriska Ceska, Victoria, B.C.

The aquatic environment has a strong impact on the morphology of vascular plants which inhabit it. An adaptation to life in water led to the reduction of conductive and mechanical tissues. Slow rate of gas exchange led to the modification of leaves in aquatics. Some of them have thin, ribbon-like leaves; others have leaves divided into small filiform segments. These modifications resulted in a convergency of forms, and not only different species within the same genus, but also different genera look very much alike. Aquatic plants can propagate vegetatively and some of them rarely produce flowers and fruits. In this situation the identification and taxonomical studies are difficult.

Two examples of the study of aquatic vascular plants in British Columbia in genera of Myriophyllum and Isoetes can demonstrate difficulties one encounters in the study of aquatic plants. In the genus Myriophyllum chromatographic patterns of flavonoids were used for identification of our species. In the genus Isoetes, the gross morphology of plants and scanning electron microscopy of megaspores and microspores had to be complemented with chromosome counts and flavenoid patterns in order to get a better understanding of this genus.

ESTUARINE MARSH CREATION AND RESTORATION ON THE EAST COAST OF VANCOUVER ISLAND -- Neil K. Dawe, Canadian Wildlife Service, R.R. 1, Site 142, C-14, Qualicum Beach, B.C., VOR 2TO.

The mandate of the Canadian Wildlife Service (CWS) is the management of the migratory bird resource. Because estuaries are important migratory bird habitat for thousands of waterbirds that winter along our coast, the CWS has been monitoring the effects of a number of restoration and marsh creation projects that have recently taken place on the east coast of Vancouver Island.

In 1969, a dyke was built on the western portion of the Englishman River estuary which prevented salt water from inundating about 40 ha of the marsh. The former estuarine channels continued to carry freshwater runoff from the City of Parksville, with the water exiting the dyked area through a culvert with a one-way flapgate. Most of the vegetation behind the dyke had converted to upland grasses, shrubs, and trees (e.g. Holcus lanatus, Epilobium angustifolium, Pyrus fusca, Alnus rubra). The vegetation along the channels included primarily freshwater species (e.g. Typha latifolia, Scirpus validus, Phalaris arundinacea) although some remanant species were also found (e.g. Carex lyngbyei, Triglochin maritimum, Distichlis spicata).

The dyke was breached in 1979 and changes in vegetation were monitored from 1979 to 1983 and in 1986. Vegetation shifted over the 8-year period from dominants of Hordeum brachyantherum, Agrostis alba, Poa pratensis, and Sonchus arvensis, to salt tolerant species that included Distichlis spicata, Salicornia europea, Atriplex patula, Salicornia virginica, and Grindelia integrifolia. By 1986, the vegetation on the western portion of the Englishman estuary resembled other natural salt marshes on the east coast of Vancouver Island.

Another project, on the Campbell River estuary, involved the creation of estuarine marshland by British Columbia Forest Products (BCFP) as mitigation for the construction of a dryland sort.

Four islands were created within an area formerly used by BCFP for storage of flat raft booms. Islands were designed by biologists from the Canadian Wildlife Service and the Department of Fisheries and Oceans, with assistance from river engineers and hydrologists. Marsh areas that were to be lost to dredging activities were used as donor sites.

The islands were created and the vegetation planted during the winter months. The vegetation was planted (23,202 plugs) in various sized blocks of 0.5 m2 and 1.0 m2 grids. Control blocks were also included.

From 1982 to 1986 the vegetation of the islands was monitored. Twenty-nine species were transplanted to the islands. The dominants were Carex lyngbyei, Eleocharis palustris, Juncus arcticus, Potentilla pacifica, and Deschampsia cespitosa. Of the 0.42 ha of marsh vegetation affected by the dredging, 0.07 ha were preserved as donorstock. As of 1986, plug mortality was about 8%. The areal extent of the vegetation on the islands in 1985 was 1.5 ha. Estimates of above-ground biomass of the vegetation on the islands suggest that it is about two-thirds that of the natural vegetation on an adjacent island. Vegetation that had naturally colonized the control plots appeared in 1986 to be rapidly approaching the transplanted vegetation in terms of cover and abundance.

SOME WETLAND ECOSYSTEMS OF THE CARIBOO FOREST REGION -- Anna Roberts, Williams Lake, B.C.

Non-forested wetlands are abundant on the plateau landscapes of the Cariboo Forest Region. In this presentation, wetland plant communities of two distinct biogeoclimatic subzones, the IDFb and the SBSa, will be described and compared. The comparison of communities shows how they reflect the different climatic and soil conditions of these two subzones. The presentation includes photographs of typical communities and descriptions of the ecology and morphological features of some indicator plant species.

Wetlands of the IDFb (Very Dry Montane Interior Douglas-Fir) subzone were studied within the IDFb2 (Eastern Fraser Plateau) variant of the subzone. The climate is relatively warm (mean annual temperature is 3.0øC) and dry (mean annual precipitation is about 450 mm). Wetlands of the SBSa (Very Dry Southern Sub-boreal Spruce) subzone were studied in the SBSa1 (Chilcotin) and SBSa3 (Nazko) variants. The climate is cold (mean annual temperature is 1.6øC) and dry (mean annual precipitation is about 400 mm). Both study areas occur on level to gently rolling plateau surfaces with poorly developed drainage patterns. Upland surficial materials are predominantly morainal deposits with high base status.

Saline mineral meadows are characteristic of the southern part of the IDFb2, whereas fens dominate the northern part. The meadow plant communities are made up of salt-tolerant plants, including alkali saltgrass (Distichlis stricta), Nuttall's alkaligrass (Puccinellia nuttalliana), seablite (Suaeda depressa) and Nevada bulrush (Scirpus nevadensis). The fens are dominated primarily by water sedge (Carex aquatilis), beaked sedge (Carex rostrata), slender sedge (Carex lasiocarpa) or awned sedge (Carex atherodes).

Wetland ecosystems of the SBSa reflect the cold climate and short growing seasons of the subzone. Sedge fens and shrub-dominated wetlands characterize this subzone; low shrub fens are common and often large. Bog willow (Salix pedicellaris) and hoary willow (Salix candida) are common in these fens. Meadows in the SBSa are often dominated by tufted hairgrass (Deschampsia cespitosa), a grass that is very uncommon in the IDFb2. Bellard's kobresia (Kobresia myosuroides), which is usually found in the alpine, is widespread in the shrub-carrs of this subzone.

OMBROTROPHIC BOG ECOSYSTEMS: A COMPARISON OF BOGS IN TEMPERATURE B.C. AND TROPICAL SUMATRAN PEATFORESTS, Michael A. Brady, Forest Science Dept., Faculty of Forestry, The University of British Columbia, 270-2357 Main Mall, Vancouver, B.C., V6T 1W5.

Ombrotrophic bogs in temperate B.C. and lowland rainforests of Sumatra, Indonesia are compared. Sites include; Camosun Bog in the UBC Endowment lands, Burns Bog on the Fraser River Delta and the peat swamp forests north of Palembang, South Sumatra, Indonesia. Similarities and differences in environmental conditions, bog formation, biogeochemistry, and successional dynamics between the two latitudes are discussed. Responses to drainage, fire and clearing are also compared.

The comparison helps to illustrate that elevated water levels, oligotrophy and acidity are dominant factors promoting ombrotrophic bog development regardless of latitude. Vegetation structure and composition, annual rainfall, temperature and surficial geology vary considerably between the three bogs.

Major disturbances affecting each bog ecosystem include; drainage, fire and clearing for cultivation or peat extraction. In areas within each of the bogs, peat aggradation has ceased and new vegetation communities have developed as a result of drying, fire and peat removal.

EFFECTS OF CLIMATIC CHANGES ON WETLANDS IN BRITISH COLUMBIA – Rolf W. Mathewes, Department of Biological Sciences, Simon Fraser University, Burnaby, B.C., V5A 1S6.

The postglacial development of all categories of wetlands, from open waters to bogs, has been influenced by macroclimatic changes. The warmest, and probably driest interval of postglacial time was the early Holocene (ca. 10,000-7500 yr BP), not the mid-Holocene emphasized in pre-1970's literature. During the early Holocene, many small waterbodies in the southern interior were dry, or existed as marshes. Larger lakes underwent periods of drawdown, exposing mudflats that were colonized by weedy herbs. Sediment stratigraphy, fossil pollen and plant macrofossils document these shifts in water level.

Beginning around 5500-6000 years ago, lake levels began to rise in the interior, and peat bog development began along the coast. Coastal upland forests became characterized by western hemlock and western redcedar, with declining abundances of Douglas-fir. Several climatically-mediated factors appear to be involved in this shift, including decreasing fire frequency and rising soil water tables after 6000 years ago.

On the Queen Charlotte Islands, a recent study confirms progressive paludification, increased peat accumulations, and spread of blanket bogs after 5000 years BP. Macrofossils, pollen, buried tree stumps, and radiocarabon dates tell a consistent story of rising water tables. Small subalpine ponds in the Queen Charlotte Ranges also began to hold water around 7000 years ago. Near Lillooet in the southern interior, water levels rose significantly in a small lake around 5600 and again around 2000 years ago, within the period of Neoglaciation in the Cordillera.

Wetlands are dynamic ecosystems, influenced by many local factors, although long-term variations in type and distribution appear to be significantly affected by marcroclimatic changes. Future climatic warming due to the expected "Greenhouse Effect" can likewise be expected to cause significant changes in our remaining wetlands.