Phytosociology and gradient analysis of a subalpine treed fen in Rocky Mountain National Park, Colorado

Abstract

The vegetation of a subalpine fen in Colorado was studied. Insight was sought into the community structure and factors influencing species distribution of a vegetation type heretofore undescribed in the southern Rocky Mountains. A vegetational gradient was evaluated using detrended correspondence analysis (DCA). Four types of vegetation were subjectively defined; these same types were distinguished by the DCA. DCA further revealed marked differences in the vegetation occurring on peat hummocks versus in hollows. Species composition was related to environment using canonical correspondence analysis (CCA). Water-table depth, hummock height, shading, groundwater temperature, and conductivity were significantly correlated with species distribution, accounting for 51% of the total species variance. Univariate regression was used to examine how tree density varied with environment. The above factors, except for shading and conductivity, were also significantly correlated with tree density. It is suggested that the peat hummocks that form on this moderate fen provide an environment similar to that of an ombrotrophic bog and that these "miniature bogs" form in areas unable to support expansive bogs. Further, these hummocks provide small-scale environmental heterogeneity that exerts a strong control over species composition that would not be evident in studies based on samples of a large areal extent. Keywords: Colorado, gradient analysis, ordination, heterogeneity, peatlands, phytosociology.

Mountain Fen Distribution, Types and Restoration Priorities, San Juan Mountains, Colorado, USA

“…Rhynchospora alba was found in one fen, and this genus was not previously known for the Rocky Mountains south of Idaho (Flora of North America Editorial Committee 2002). Unlike many regions with peatlands (Rydin and Jeglum 2006), fens in the Rockies have little tree cover (Johnson 1996). Only 5% of the study fens supported any trees, and only one species, Picea engelmannii, commonly occurred in fens.…”

Influence of Bedrock Geology on Water Chemistry of Slope Wetlands and Headwater Streams in the Southern Rocky Mountains

“…Nutt.) (<50% overstory canopy cover) typical of Rocky Mountain forested wetlands (Johnson 1996(Johnson , 1997Lemly 2007).…”

“…Compared to the rich and extreme-rich peatlands that support rare plant species and calciphilic plant communities (Cooper 1996;Chapman et al 2003;Johnson and Steingraeber 2003), little is known about the water chemistry and plant communities of intermediate types (Johnson 2001, but see Cooper 1990Johnson 1996). To increase understanding of the biogeochemistry of Rocky Mountain slope wetlands, we compared wetland porewater and streamwater chemistry in basins underlain entirely by crystalline bedrock with water chemistry in basins containing a mixture of crystalline and sedimentary bedrock.…”

Clonal structure and hybrid susceptibility to a smut pathogen in microscale hybrid zones of northern wetlandCarex(Cyperaceae)

“…Because the occurrence of the pathogen is likely to be limited by its ability to disperse from one place to another and by other environmental factors such as water depth and humidity, spatial relationships of the smut pathogen may be more important than host genotype (Jarosz and Burdon, 1988). Thus, spatial pattern must be examined as an alternative hypothesis to genetically based associations that can occur between plant and pathogen (Jean and Bouchard, 1993;Johnson, 1996).…”