Athyrium Distentifolium Research Articles

A morphometric analysis of ScottishAthyrium distentifolium: a contribution to the BAP

Summary A morphologically distinct variety of Athyrium distentifolium called A. distentifolium var. flexile has been found only in Scotland. Research was undertaken for aUK Biodiversity Action Plan. To confirm that this taxon has a definitely recognisable morphology, a morphometric analysis was used on the range of characters used to define this variety. It showed that it can be clearly differentiated.

A single gene with pleiotropic effects accounts for the Scottish endemic taxon Athyrium distentifolium var. flexile

○ Experiments were conducted to determine the genetic relationship between the alpine fern Athyrium distentifolium and the Scottish endemic taxon A. distentifolium var. flexile. ○ Segregation of the taxa was studied after growing sporophytes from spore families, and after selfing and crossing gametophytes. The growth of both gametophytes and sporophytes was measured under a range of nutrient regimes. ○ The distinction between the two taxa is due to variation at a single gene with pleiotropic effects expressed at both the sporophyte and gametophyte stages. A. distentifolium sporophytes (genotypes A D /A D or A D /A F ) are taller, have fewer fronds, and produce fewer spores than A. distentifolium var. flexile sporophytes (genotype A F /A F ). Gametophytes containing the A F allele have a 50% higher growth rate than those with the A D allele on a range of media. ○ The polymorphism may be maintained by a balance between selection for and against the A F allele at the gametophyte and sporophyte stages of the life cycle, respectively. Implications for the conservation of the A. distentifolium var. flexile taxon are discussed.

Vegetation changes in forests of the Krkonoše Mts. over a period of air pollution stress (1980–1995)

Species composition of the understory of spruce (Picea abies (L.) Karsten) and beech (Fagus sylvatica L.) forests subjected to intense air pollution stress in the Krkonose Mts., Czech Republic, showed directional changes over the last 15 years. The changes were documented with repeated observations of 29 permanent plots, initiated in 1980 and analysed with constrained ordination methods (Canonical Correspondence Analysis). Ground layer changes were mainly associated with the loss of canopy foliage from air pollution stress. The increased amount of the light at ground level resulted in increased herb cover. The initially dominant species (e.g., Calamagrostis villosa (Chaix) J. F. Gmelin, Deschampsia flexuosa (L.) P. B., Vaccinium myrtillus L., Athyrium distentifolium Tausch) were those that increased in cover. Moss cover, and moss and herb richness, declined over the course of the study. Thus, the changes in tree canopy are accompanied with changes in the forest understory, which in turn can affect the dynamics of these forests.

Athyrium distentifoliumvar.flexile: an endemic variety

Summary Athyrium distentifolium is found in scattered sites in the Central and Northern Highlands of Scotland. In a few localities in the Central Highlands there is also an endemic variety: A. distentifolium var. flexile. Both types are found together in polymorphic populations with the two distinct forms. A. distentifolium can only grow well with moderate nutrients and in the polymorphic populations A. distentifolium is smaller than elsewhere and frequently infertile. A. distentifolium var. flexile is a smaller plant which is more frequently fertile than A. distentifolium in polymorphic populations and appears particularly well adapted to grow in stressful environments with low nutrient status.

Ecological optima and tolerances of Thelypteris limbosperma, Athyrium distentifolium, and Matteuccia struthiopteris along environmental gradients in Western Norway

The distribution and abundance of Thelypteris limbosperma, Athyrium distentifolium, and Matteuccia struthiopteris are modelled statistically in relation to 14 environmental variables along the major climatic, topographic, and edaphic gradients in western Norway. The data are from 624 stands from which measurements or estimates of mean January and mean July temperatures, humidity, altitude, aspect, and slope are available. From 182 of these stands eight soil variables have also been measured. The species responses are quantified by two numerical methods: Gaussian logit regression and weighted averaging (WA) regression. The estimated WA optima suggest that A. distentifolium has an ecological preference for low July and January temperatures, high altitudes, and soils of low-medium pH and base content. The species shows statistically significant Gaussian responses with summer temperature, humidity (= Martonnes humidity index), altitude, slope, aspect, pH, cation exchange capacity, and base saturation with optima of 8.7 °C, 188.9, 1220 m, 28°, 29°, 4.8, 13.77 mEq 100 g dry soil-1, and 13.4%, respectively. These suggest that the occurrence and relative abundance of A. distentifolium are well predicted by summer temperature, topography, and soil pH and base status. T. limbosperma has WA optima that suggest that it favours moderately high winter and summer temperatures, high humidity, medium altitude, and soils of low pH and base content. It has significant Gaussian responses to summer temperature (optimum =12.6 °C), winter temperature (-1.8 °C), humidity (179.2), altitude (459.5 m), slope (22.5°), and Na (0.7 mg 100 g dry soil-1). These suggest that climatic factors, altitude, and slope are significant predictors for its occurrence and abundance. M. struthiopteris has high WA optima for summer temperature, pH, Ca, Mg, K, Na, cation exchange capacity (CEC), and base saturation, and a low optima for humidity and winter temperature. Of these, summer temperature (16.0 °C), Ca (63.1 mg 100 g dry soil-1), Mg (41.0 mg 100 g dry soil-1), K (23.6 mg 100 g dry soil-1), Na (5.0 mg 100 g dry soil-1), CEC (60.7 mEq 100 g dry soil-1), and base saturation (56.3%) have significant Gaussian logit responses, as do aspect (150.2°) and loss-on-ignition (9.4%). These results suggest that the occurrence and relative abundance of M. struthiopteris are well predicted by high soil base cations, a generally southern aspect, low organic content in the soil, and high July temperatures.

Frond development and phenology of Thelypteris limbosperma, Athyrium distentifolium, and Matteuccia struthiopteris in Western Norway

Odland, A. 1995. Frond development and phenology of Thelypteris limbosperma, Athyrium distentifolium, and Matteuccia struthiopteris in Western Norway. — Nord. J. Bot. 15: 225–236. Copenhagen. ISSN 0107–055X.The pattern of growth and phenology of Thelypteris limbosperma, Athyrium distentifolium, and Matteuccia struthiopteris fronds has been investigated, with particular emphasis on height increments of the sporophytes and the development of fertile fronds. In order to study both interspecific and intraspecific differences, fern stands along altitudinal gradients have been monitored. To investigate the initiation of fertility, fronds representing different developmental stages have been sampled. Climatic data have been collected with a data‐logger during the study periods.The ferns show significant differences in growth pattern and phenology. Matteuccia struthiopteris has a growth curve that is best described as monomolecular, characterised by high growth rates during the early developmental stage, while the development of Thelypteris limbosperma and Athyrium distentifolium follow a logistic growth curve. The species need different periods of time to develop their fronds. The main frond elongation does not start before soil temperature has reached 7 C. After that, the growth is mainly controlled by air temperature. Within the interval when mean maximum temperatures are 8–20 C, all three ferns showed increased growth rates with increasing air temperatures, but the increase was greatest in M. struthiopteris. At higher temperatures, the growth rate of M. struthiopteris and T. limbosperma decreased. Athyrium distentifolium is characterised by producing sori at an early developmental stage. Fertile Matteuccia strurhiopteris fronds are developed at a much later developmental stage. Thelypteris limbosperma needs a longer period of time to produce mature fronds than the other species. The investigation indicates that plant growth and development are determined by both internal and external factors. It is concluded that growth rate, phenology, and the ability of ferns to produce mature fronds reveal close similarities with their response to environmental variables, and hence with their broad‐scale geographical distributional patterns.

A synecological investigation of Athyrium distentifolium‐dominated stands in Western Norway

This paper presents results of a study on the synecology of Athyrium distentifolium. The investigation is based on phytosociological and ecological analyses of stands dominated by A. distentifolium within its whole distributional area in Western Norway. The distribution and floristic composition of the stands are related to different environmental parameters such as climate, soil and topography. The data are analysed by numerical methods, of which two‐way indicator species analysis (TWINSPAN), canonical correspondence analysis (CCA), and simple discriminant functions (DISCRIM) are the most useful. Based on a TWINSPAN classification of the 211 investigated stands, 9 different groups (types) are distinguished. These belong mainly to three phytosociological alliances: Cryptogrammo‐Athyrion alpestris (1 group), Lactucion alpinae (5 groups) and Vaccinio‐Piceion (3 groups). The quadrats are in most cases very poor in species, even in edaphically rich areas. Soil richness in the stands is very variable. A. distentifolium may be dominant in edaphically rich areas and it is not a calciphobe species in W. Norway. Most stands show no signs of human influence. Length of snow‐lie is assumed to be of major importance for the development and distribution of A. distentifolium stands.

Quantitative vegetation-environment relationships in west norwegian tall-fern vegetation.

The aims of this paper are to detect floristic variation within different types of tall‐fern dominated vegetation and to interpret these patterns in terms of environmental variables. Numerical approaches have been applied to a large and varied vegetational data‐set with associated environmental data from stands dominated by Athyrium distentifolium, Thelypteris limbosperma, and Matteuccia struthiopteris in different parts of western Norway. The numerical procedures of two‐way indicator species analysis, simple discriminant functions, and canonical correspondence analysis have been used, and the strengths and weaknesses of these as tools in discerning vegetational‐environmental relationships are discussed. For each of the 96 quadrats investigated, 17 environmental variables were measured. The investigation shows that some of the observed differences in vegetational composition can be explained in terms of relatively simple soil and climatic variables measured for each quadrat. The ferns appear to be ecologically well separated. T. limbosperma‐dominaled stands are mainly characterised by low soil fertility, high January temperature, and high humidity. A. distentifolium‐dominated stands are associated with low winter temperatures, and M. struthiopteris‐dominated stands have high soil fertility and high summer temperatures.

Pre– and subalpine tall herb and fern vegetation in Røldal, W Norway

Six tall herb and fern vegetation types in Røldal have been investigated. They are referred to the alliances Lactucion alpinae and Alno–Ulmion. Lactucion alpinae is divided into two suballiances, one oligotrophic to mesotrophic (Dryoptero–Calamagrostenion purpureae) to which are referred Athyrium distentifolium– Salix scrub, and Athyrium distentifolium meadow, and one eutrophic (Lactucenion alpinae) to which belongs Geranium sylvatkum meadow and Lactuca alpina meadow. Alnus incana forest, herb/fern and Matteuccia struthiopteris types belong to Alno–Ulmion. Lactucion alpinae is considered subalpine, whilst Alno Uimion is prealpine.The pre– and subalpine zones are considered oceanic sections of middle– and upper oroboreal vegetation zones.