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In this paper, we present high-resolution, contiguous plant macrofossil records taken from two glacial cirque mountain wetland ecosystems located in the subalpine zone of the Eastern Carpathians. We provide 1) a detailed reconstruction of plant succession from mountain peatland ecosystems; 2) a possible scenario of Holocene paleohydrological changes; 3) the presence of rare plants presently considered glacial relicts, e.g. Meesia triquetra; and 4) the peat forming potential of certain plants at altitudes above 1800 m a.s.l. At Gargalau, a gradual decrease of water level and isolation from ground water influence approximately 7000 cal yr BP trigged the colonization of minerotrophic Sphagnum species (S. teres, S. centrale and S. subsecundum). The decline of Sphagnum subsecundum ca. 3000 cal yr BP was most likely caused by an increase of water level and competiton with Sarmentypnum sarmentosum populations. In the Late Holocene, ca. 2000 cal yr BP, Selaginella selaginoides expansion was recorded, followed by the reappearance of Sphagnum populations, most likely due to a lowering of the water table. The Gropile ecosystem transformed from a shallow lake into peatland at ca. 4200 cal yr BP. The temporary presence of Warnstorfia exannulata in peat sediments ca. 2300, 1600, 1300–1200, and 700–600 cal yr BP may indicate an increase of water level and very wet habitat, or the presence of small ponds. Paleohydrological changes only partly agree at both studied wetlands, suggesting the importance of local climatic and morphological conditions on past vegetation development. According to our paleoecological data, Straminergon stramineum indicates wet stages in peatlands and cannot be considered a high peat-forming species in subalpine zones in European mountain ranges. Projected warm and dry conditions may trigger mountain peatland water tables in Eastern Carpathians to decline, potentially resulting in the expansion of moss species that demand more acidic and drier habitats, e.g. Sphagnum russowii.

Sphagnum alaskense Andrus & Janssens, sp. nov. is described as a new species in section Sphagnum. It is a weakly to moderately minerotrophic species occurring from Alaska south to the state of Washington. Sphagnum alaskense differs from S. centrale on the basis of weak or absent stem cortical cell fibrils, branch chlorophyll cells lacking thickened end walls in transverse section, and branch leaf hyaline cells often with ridges running parallel to the long axis of the leaf where the hyaline cells overlap the overlying chlorophyll cells.

A bioclimatic model based on bryophyte species distribution and abundance relative to climate was coupled with climatic and geographical data obtained from Leemans and Cramer (1991) and the Canadian Climate Center (CCC) General Circulation model (GCM) at 1XCO2 in order to reconstruct the present geographical distribution of seven peatland types in the Mackenzie River Basin. The geographical distribution of 195 peatlands previously identified by type were used to test the validity of the reconstructions. The test revealed that the reconstruction using data from Leemans and Cramer was more accurate than the reconstruction using the CCC GCM data. For this reason, the CCC 1XCO2 data was subtracted from the CCC 2XC02 climatic data to produce an anomalies data set which was then added to the Leemans and Cramer data to project the distribution of the seven types of peatlands at 2XCO2. Results of this prediction were then compared to predictions using 2XC02 data obtained from the Geophysics Fluid Dynamics Laboratory (GFDL) GCM. The position of the southern limits of peatland distribution was compared to past distributions resulting from a warming period in the early to mid Holocene. Results of the predictions for the two climate change scenarios indicated a northward migration of the southern boundary of peatland ecosystems of approximately 780 km in the central portion of the Mackenzie River Basin. The model also predicted that Mid-Boreal peatlands would be located along a diagonal running from southeast to northwest from 600 longitude to an area just south of the Mackenzie Delta for both scenarios. High-Boreal and Subarctic peatlands were located to the north of the diagonal, while Low-Boreal peatlands were located to the south. However, the CCC anomalies + Leemans and Cramer predictions did not clearly define the Low-Boreal since Low-Boreal indicators were only located in the Cordilleran Ecological Province. Ecological diversity is anticipated to be maintained in the peatlands because all types were predicted to be found in the Basin at 2XC02 but at different locations. Comparisons between the predicted position of the southern limits of peatland distribution and that during the early to mid Holocene indicate that the model's predictions were reasonable. Global warming resulting from increased concentrations of such greenhouse gases as CO2, CH4, and NOx could produce temperature increases as much as 1.5 to 4.60C by the middle of the 21st century (Mitchell et al. 1990). Northern and continental regions in particular will experience significant warming, especially during the spring and winter months. Increases in annual temperature for northern locations in North America are anticipated to be in the order of 3.7 to 4.60C (Cohen 1993). Elevated temperatures are expected to produce droughts that will affect site water balance and runoff, and cause major shifts in the distribution of ecosystems on a global scale (Houghton et al. 1990; Vitousek 1994). These effects will be quite noticeable in such ecosystems as wetlands, and in particular peatlands, which are especially sensitive to climate and fluctuations in water levels. Peatlands are wetlands that have a minimum accumulation of 0.5 m of peat, and are usually divided into two types: bogs and fens. This division is based on whether the water supply is ombrotrophic (bogs) or minerotrophic (Gore 1983; Sjors 1952). The largest concentration of peatlands is in the boreal and subarctic regions of the Northern Hemisphere (Gore 1983). The northern distribution indicates that peatlands are climatically sensitive ecosystems and that they are primarily found in areas that have wet and humid climates where there are no sustained dry periods (Moore & Bellamy 1974). 0007-2745/98/572-587$1.75/0 This content downloaded from 207.46.13.128 on Tue, 06 Sep 2016 05:18:25 UTC All use subject to http://about.jstor.org/terms 1998] GIGNAC ET AL.: PREDICTED MIGRATION OF PEATLANDS 573 Peatland formation is a function of two climatic variables, precipitation and evaporation, and generally they occur where evaporation does not exceed precipitation i.e., where potential evapotranspiration ratios < 1 (Gignac 1993). Not only does the macroclimate affect the presence of peatlands, but it also affects the distribution of different forms of bogs, and the height that they attain above the surrounding landscape (Ivanov 1981; Moore & Bellamy 1974). Among climatic variables that have been correlated to the different types of bogs are: total precipitation (Eurola 1962; Ruuhijirvi 1960), number of precipitation days (Taylor 1983), and precipitation and temperature together (Ivanov 1981; Moore & Bellamy 1974). Fens can also be found in all climatic zones where peatlands occur, and some types of fens can be placed into different zones based on climatic factors (Gignac & Vitt 1990; Moore & Bellamy 1974). Peatland vegetation, particularly bryophyte species, are very sensitive to changes in the height of the water table (Gignac et al. 1991; Gorham & Janssens 1992; Nicholson et al. 1996). The height of the peat surface above the water table and thus the height of the vegetation are a function of climatic conditions, particularly temperature and precipitation (Gignac & Vitt 1990). Increases in temperature enhance evaporation and if precipitation remains constant or diminishes, it should cause a lowering of the water table. A decrease of the height of the water table will result in subtle changes in the presence, absence, and abundance of bryophyte species (Andrus et al. 1983; Gignac & Vitt 1990; Gignac et al. 1991; Vitt et al. 1975). Thus, peatland vegetation is very sensitive to climate. Changes in peatland vegetation should offer an early warning of large-scale climatic changes before they occur in more stable and larger ecosystems such as the boreal forest. Because peatlands are sinks and sources of the greenhouse gases CO2 and CH4, any modification of the climate could affect the quantities of these gases released to the atmosphere (Bubier et al. 1993; Roulet et al. 1993; Roulet et al. 1994). Accumulating deposits of peat retain water causing local water tables to rise (Ingram 1983) which has lead to large scale peatland formation through paludification in northern landscapes (Nicholson & Vitt 1990; Sjors 1963). Under a warmer drier climate methane emissions will initially increase with melting of permafrost and rising of water tables (Liblik et al. 1997). Once new drainage patterns establish, increased oxidation of the peat will release more CO2 to the atmosphere (Gorham 1991). Organic acids are also produced from decomposing mosses and as a result of increased decomposition caused by warmer climates, local streams may become acidified (Bayley et al. 1992; Hogg et al. 1992). The microclimate of the peatland will also change causing a reduction of evapotranspiration rates because of the shift from areas with free standing water to shaded areas as a result of increased tree or shrub cover (Ingram 1983). Subsurface soil temperatures will also increase with the resulting degradation of permafrost in many north

Sphagnum majus subsp. norvegicum and S. subtile are reported for the first time in the Iberian Peninsula from a mountain mire in northwestern Spain. Chemical parameters, algae, bryophytes, and vascular plants were determined. Chemical data and vegetation served to classify the mire as a poor fen although some of its plant species can be regarded as weakly minerotrophic. The Sphagnum flora of the Iberian Peninsula is quite imperfectly known, and only general treatments on European taxa are available. Only Casares' (1925) work deals with the genus in the Iberian Peninsula, but today it is out of date. There are no modern treatments of the Iberian species of the genus except the distribution of the taxa of sect. Sphagnum (Casas et al. 1992). Since no other section has been thoroughly studied, the verified Iberian members of the genus and their distribution remain unknown. The treatment of the group by Daniels and Eddy (1985) is too general concerning the geographical distribution in the Iberian Peninsula. Casas' (1991) checklist of the Spanish mosses is the only modern reference work for the area regarding sphagna. In the past few years, collections of Sphagnum were made in Zamora Province, northwestern Spain. Among these collections, one sample of Sphagnum majus (Russ.) C. Jens. subsp. norvegicum Flatberg and one of S. subtile (Russ.) Warnst. were collected from a small mire in the Segundera Mountains, the first collection of these mosses for the Iberian Pen

Scorpidium scorpioides (Hedw.) Limpr. is a characteristic species of rich fens, where its chemical environment is one of high pH, calcium content, alkalinity, and conductivity. It often forms a dominant component of rich fen peat deposits. When grown under experimental conditions, Canadian plants of this species respond differently than plants from The Netherlands. Canadian plants respond best when grown in extreme-rich fen waters, while plants from The Netherlands respond best in waters from moderate-rich fens and in nutrient enhanced conditions. Saline waters yield no or limited growth responses from plants in both areas. The results suggest ecotypic variation between plants from the two continents. Also, the results suggest that chemical factors (i.e., saline water) affect the presence and growth of S. scorpioides. These chemical factors may have had an influence on the past distribution of the species. Abstract. Scorpidium scorpioides (Hedw.) Limpr. is a characteristic species of rich fens, where its chemical environment is one of high pH, calcium content, alkalinity, and conductivity. It often forms a dominant component of rich fen peat deposits. When grown under experimental conditions, Canadian plants of this species respond differently than plants from The Netherlands. Canadian plants respond best when grown in extreme-rich fen waters, while plants from The Netherlands respond best in waters from moderate-rich fens and in nutrient enhanced conditions. Saline waters yield no or limited growth responses from plants in both areas. The results suggest ecotypic variation between plants from the two continents. Also, the results suggest that chemical factors (i.e., saline water) affect the presence and growth of S. scorpioides. These chemical factors may have had an influence on the past distribution of the species. Abstract. Scorpidium scorpioides (Hedw.) Limpr. is a characteristic species of rich fens, where its chemical environment is one of high pH, calcium content, alkalinity, and conductivity. It often forms a dominant component of rich fen peat deposits. When grown under experimental conditions, Canadian plants of this species respond differently than plants from The Netherlands. Canadian plants respond best when grown in extreme-rich fen waters, while plants from The Netherlands respond best in waters from moderate-rich fens and in nutrient enhanced conditions. Saline waters yield no or limited growth responses from plants in both areas. The results suggest ecotypic variation between plants from the two continents. Also, the results suggest that chemical factors (i.e., saline water) affect the presence and growth of S. scorpioides. These chemical factors may have had an influence on the past distribution of the species. Brown mosses, composed of species in the genera Calliergon, Calliergonella, Campylium, Cratoneu- ron, Drepanocladus s.l., Meesia, Scorpidium, and Tomentypnum-along with a few of the more hy- grophytic species of Brachythecium and Hypnum - are characteristic of rich-fen habitats, peatlands characterized by minerotrophic, alkaline (see Wet- zel 1975) water. Nutrients, especially nitrogen and phosphorus, are present in the surface waters in low amounts. However, due to seasonal flow of water, plants are able to take up more nutrients than are present in oligotrophic bogs; thus rich fens are me- sotrophic ecosystems (Vitt & Kuhry 1992). Three types of base-rich (Ca, Mg, or Na) fens occur in boreal western Canada. Moderate-rich fens are characterized by pH's between 5.5 and 7.0, small amounts of bicarbonate, somewhat seasonally vari- able water tables, and no marl deposition. Char- acteristic species include Brachythecium mildean- um (Schimp.) Schimp. in Milde, Calliergonella cuspidata (Hedw.) Loeske, Drepanocladus aduncus (Hedw.) Warnst., D. aduncus var. polycarpus (Bland. ex Voit) G. Roth, D. lapponicus (Norrl.) Smirn., D. vernicosus (Mitt.) Warnst., and Helodium blandowii (Web. & Morh) Warnst. (Chee & Vitt 1989). Ex- treme-rich fens have pH's higher than 6.5, large Brown mosses, composed of species in the genera Calliergon, Calliergonella, Campylium, Cratoneu- ron, Drepanocladus s.l., Meesia, Scorpidium, and Tomentypnum-along with a few of the more hy- grophytic species of Brachythecium and Hypnum - are characteristic of rich-fen habitats, peatlands characterized by minerotrophic, alkaline (see Wet- zel 1975) water. Nutrients, especially nitrogen and phosphorus, are present in the surface waters in low amounts. However, due to seasonal flow of water, plants are able to take up more nutrients than are present in oligotrophic bogs; thus rich fens are me- sotrophic ecosystems (Vitt & Kuhry 1992). Three types of base-rich (Ca, Mg, or Na) fens occur in boreal western Canada. Moderate-rich fens are characterized by pH's between 5.5 and 7.0, small amounts of bicarbonate, somewhat seasonally vari- able water tables, and no marl deposition. Char- acteristic species include Brachythecium mildean- um (Schimp.) Schimp. in Milde, Calliergonella cuspidata (Hedw.) Loeske, Drepanocladus aduncus (Hedw.) Warnst., D. aduncus var. polycarpus (Bland. ex Voit) G. Roth, D. lapponicus (Norrl.) Smirn., D. vernicosus (Mitt.) Warnst., and Helodium blandowii (Web. & Morh) Warnst. (Chee & Vitt 1989). Ex- treme-rich fens have pH's higher than 6.5, large Brown mosses, composed of species in the genera Calliergon, Calliergonella, Campylium, Cratoneu- ron, Drepanocladus s.l., Meesia, Scorpidium, and Tomentypnum-along with a few of the more hy- grophytic species of Brachythecium and Hypnum - are characteristic of rich-fen habitats, peatlands characterized by minerotrophic, alkaline (see Wet- zel 1975) water. Nutrients, especially nitrogen and phosphorus, are present in the surface waters in low amounts. However, due to seasonal flow of water, plants are able to take up more nutrients than are present in oligotrophic bogs; thus rich fens are me- sotrophic ecosystems (Vitt & Kuhry 1992). Three types of base-rich (Ca, Mg, or Na) fens occur in boreal western Canada. Moderate-rich fens are characterized by pH's between 5.5 and 7.0, small amounts of bicarbonate, somewhat seasonally vari- able water tables, and no marl deposition. Char- acteristic species include Brachythecium mildean- um (Schimp.) Schimp. in Milde, Calliergonella cuspidata (Hedw.) Loeske, Drepanocladus aduncus (Hedw.) Warnst., D. aduncus var. polycarpus (Bland. ex Voit) G. Roth, D. lapponicus (Norrl.) Smirn., D. vernicosus (Mitt.) Warnst., and Helodium blandowii (Web. & Morh) Warnst. (Chee & Vitt 1989). Ex- treme-rich fens have pH's higher than 6.5, large

Three borealfen mosses are reported new to the southern Rocky Mountains of Colorado. Scorpidium scorpioides (Hedw.) Limpr. occurs in extreme rich fens in the area of South Park. It occupies seasonal pools in high elevation mires where high pH and marl deposits occur. Paludella squarrosa (Hedw.) Brid. forms cushions in two rich fens above treeline on Guanella Pass where it is fed by water with nearly neutral pH. Sphagnum contortum K. F. Schultz occurs in two poor to intermediatefens in mires on the edge ofsmall moraine-dammedponds in Rocky Mountain National Park. It forms a continuous carpet at the water's edge where it is seasonallyflooded. All three species are new to the southern Rocky Mountains and occur in similar habitats to those described for these species in boreal mires. The presence of these species and knowledge of their ecology help elucidate the relationship between the southern Rocky Mountain and the boreal mire floras. The moss flora of the southern Rocky Mountain region is relatively well-known from the work of Flowers (1973) and Weber (1973). However, the flora of the fens (minerotrophic mires) has received surprisingly little attention. Most fen vegetation in this region is dominated by Carex spp., Eleocharis quinqueflora, and in some cases Salix spp. Thus, peat is largely derived from the roots and leaves of these plants. Mosses are not abundant in most fens and moss carpets are largely restricted to rich fens and fens with gently but constantly flowing water. Mosses that dominate the bottom layer of southern Rocky Mountain fens are also important in boreal peatlands and include Aulacomniumpalustre, Cam- pylium stellatum, Drepanocladus aduncus, and To- menthypnum nitens. This paper reports the discovery of three impor- tant boreal fen mosses from mires in the southern Rocky Mountains of Colorado and describes their habitats.

Sphagnum austinii Sull. is a common hummock former in open weakly minerotrophic peatlands along the Pacific coast of North America from Washington to southeastern Alaska. It also occurs along the eastern North American coast and in Europe. Separation from the closely related S. portoricense is made by the less pronounced branch cortical cell projections with end pores adjacent to the wood cylinder.

A quantitative analysis of gametophyte characters of Tomenthypnum falcifolium (Ren. ex Nichols) Tuomikoski in Ahti and Fagerstin and T. nitens (Hedw.) Loeske shows significant differences in certain measurements of leaf length and leaf shape. These differences are still present in mixed collections of the two species. Tomenthypnum falcifolium appears to be endemic to the boreal and sub-arctic zones of North America. Quantitative ecological analyses, along with field observations, in westcentral Canada show that Tomenthypnum falcifolium occurs in weakly minerotrophic areas (poor fens) forming hummocks with Sphagnum angustifolium (Russ.) C. Jens. and S. magellanicum Brid., while T. nitens occurs in minerotrophic to strongly minerotrophic areas (rich fens) forming lawns and small hummocks often in association with Sphagnum warnstorfii Russ. and other 'brown

Drepanocladus crassicostatus Janssens is described as new from North American collections of living populations and from fossils of Pleistocene and Holocene age. The species is compared with D. capillifolius (Warnst.) Warnst., D. exannulatus var. rotae (De not.) Loeske, D. exannulatus var. purpurascens (Schimp.) Herz. and D. trichophyllus (Warnst.) Podp. Drepanocladus crassicos- tatus is differentiated from these mosses by less well-developed groups of alar cells, a strong, wide costa, and the absence of brush-like branch tips. It is known only from western North America and occurs in more minerotrophic habitats than D. trichophyllus. Evidence for the occurrence of D. trichophyllus in North America is a single collection. Many late Tertiary and Quaternary sediments in glaciated and periglacial areas of North America are particularly rich in bryophyte remains. Fragments of mosses can be extracted from fluviatile, deltaic, and lacustrine sediments, in addition to peats. The specimens are not substantially altered by diagenetic processes and most can be handled by the same techniques as are used with specimens of living bryophyte populations. Late Cenozoic bryophytes in North America can all be referred to extant moss taxa, and the distinct microscopic features of the leaves make it possible to identify most frag- ments to species level. Miller (1980) listed 725 records in his catalogue of Quaternary fossil bryophytes of North America. In addition, approximately one thousand bryophyte records from Pleistocene and Holocene sediments have been accumulated in the course of my work on Alaskan, Yukon, and other sediments from the Arctic Archipelago and on Min