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Moss synusiae in South Estonian forests
Abstract
On the Karula Upland, South Estonia, the forest moss layer was analysed using a transect of 726 contiguous 0.2×0.2 m plots.
The sample plots were classified according to a multistage clustering procedure based on the sequential use of algorithms
with different criteria. Several obtained clusters are rather similar in species composition, but abundance relationships
among dominant species are distinctly different. For detailed analysis of mutual relations among societies a formal definition
of adjacency is proposed, and two aspects of the cluster continuum — transitionality and distinctness — are estimated. It
appears that almost all resulting societies are very distinct (P<0.05), but at the same time can be continual in the sense of transitionality. Spatial changes in vegetation along transects
are also discontinuous. The null hypothesis assuming the independency of neighbouring sample plots type was refuted withP=0.01. The spatial extent of different synusiae is typically several times larger than it should be if there were no structure
in moss vegetation.
... In the moss layer of the Estonian Vaccinium site type, discontinuity rather than continuity was prevalent (Paal 1994). This was presumably a result of spatially discrete microhabitat conditions (Barkman 1968, 1973, Norin 1979, Dierschke 1994, different ways/strategies of species' distribution (Wilmanns 1989) and uneven probability of species' co-occurrence, i.e. assembly rules (see Götzenberger et al. 2012). ...
... This was presumably a result of spatially discrete microhabitat conditions (Barkman 1968, 1973, Norin 1979, Dierschke 1994, different ways/strategies of species' distribution (Wilmanns 1989) and uneven probability of species' co-occurrence, i.e. assembly rules (see Götzenberger et al. 2012). Therefore, changes in plant cover will not occur as a gradient but as a mosaic of discrete assemblages (Razumovskii 1981, Yastrebov 1991, Paal 1994. Patterns occur at the scale of synusiae (Korchagin 1976, Minarski & Daniёls 2006 or (for field and moss layers together) at the scale of microcoenoses (Barkman 1968, Mirkin 1986). ...
... Patterns occur at the scale of synusiae (Korchagin 1976, Minarski & Daniёls 2006 or (for field and moss layers together) at the scale of microcoenoses (Barkman 1968, Mirkin 1986). In boreal forests that corresponds in metric scale to 0.1-10 m 2 , e.g. in mixed Vaccinium site type Picea abies-Pinus sylvestris stands in southern Estonia the diameter of moss synusiae varies from 0.3 to 1.4 m (0.1-2.1 m 2 ) (Paal 1994). Komarova (1993) stated that, after fires, three main processes occur in the structural changes of field layer synusiae of Pinus sibirica forests in the Sikhote-Alin mountains: (i) some types of synusiae vanish, (ii) synusiae of some other types are partly replaced by the synusiae already existing in the community, and (iii) synusiae of new types previously not present in the community emerge due to the disappearance of previous species and introduction of new ones. ...
The elementary structural units where changes of plant communities come about are synusiae and studies of successional processes induced by external factors should focus on that scale. Synusia is a structural part of a plant community inhabiting a special microhabitat, with a specific floristic composition and consisting of species that belong to the same stratum and that do not differ fundamentally in either periodicity or way of exploitation of their environment. We studied the responses of the moss synusiae to the cement kiln dust pollution in Myrtillus site type forests in the vicinity of the Kunda cement plant (North Estonia). The synusiae were clustered into eight societies. The species content of the bryophyte synusiae changed completely along the alkaline pollution gradient. Synusiae of Dicranum polysetum-Pleurozium schreberi, Aulacomnium palustre-Hylocomium splendens and Ptilium crista-castrensis-Hylocomium splendens societies, characteristic of unpolluted forests, were replaced gradually by the synusiae of Rhytidiadelphus squarrosus-Hylocomium splendens, Climacium dendroides-Hylocomium splendens and Rhodobryum roseum-Rhytidiadelphus triquetrus societies as pollution increased. Brachytheciurn rutabulum-Rhytidiadelphus triquetrus and Fissidens dubius-Rhytidiadelphus triquetrus societies were indicative of forests with heavy alkaline pollution. The composition of epiphytic bryophytes also changed almost completely along the pollution gradient; Fissidens adianthoides, Tortula ruralis and Barbula unguiculata were indicative of the heavily polluted zone. We conclude that alkaline pollution has a clearly detectable impact on the forests' bryophyte synusiae in terms of both species composition and typological structure.
... In the moss layer of the Estonian Vaccinium site type, discontinuity rather than continuity was prevalent (Paal 1994). This was presumably a result of spatially discrete microhabitat conditions (Barkman 1968, 1973, Norin 1979, Dierschke 1994, different ways/strategies of species' distribution (Wilmanns 1989) and uneven probability of species' co-occurrence, i.e. assembly rules (see Götzenberger et al. 2012). ...
... This was presumably a result of spatially discrete microhabitat conditions (Barkman 1968, 1973, Norin 1979, Dierschke 1994, different ways/strategies of species' distribution (Wilmanns 1989) and uneven probability of species' co-occurrence, i.e. assembly rules (see Götzenberger et al. 2012). Therefore, changes in plant cover will not occur as a gradient but as a mosaic of discrete assemblages (Razumovskii 1981, Yastrebov 1991, Paal 1994. Patterns occur at the scale of synusiae (Korchagin 1976, Minarski & Daniёls 2006 or (for field and moss layers together) at the scale of microcoenoses (Barkman 1968, Mirkin 1986). ...
... Patterns occur at the scale of synusiae (Korchagin 1976, Minarski & Daniёls 2006 or (for field and moss layers together) at the scale of microcoenoses (Barkman 1968, Mirkin 1986). In boreal forests that corresponds in metric scale to 0.1-10 m 2 , e.g. in mixed Vaccinium site type Picea abies-Pinus sylvestris stands in southern Estonia the diameter of moss synusiae varies from 0.3 to 1.4 m (0.1-2.1 m 2 ) (Paal 1994). Komarova (1993) stated that, after fires, three main processes occur in the structural changes of field layer synusiae of Pinus sibirica forests in the Sikhote-Alin mountains: (i) some types of synusiae vanish, (ii) synusiae of some other types are partly replaced by the synusiae already existing in the community, and (iii) synusiae of new types previously not present in the community emerge due to the disappearance of previous species and introduction of new ones. ...
... Ordination was carried out with principal component analysis (CANOCO package, version 3.1, Ter Braak 1990; and CANODRAW package, version 3.0, Smilauer 1992) with default parameters settings. For the estimation of the adjacency of clusters , the distances of all specimens, or operational taxonomic units (OTUs), from all centroids (except the cluster to which the OTU belongs) were calculated according to the postulate that the jth cluster is interpreted as being adjacent to the ith cluster if the distance between at least one of the OTUs of the ith cluster and the centroid of the jth cluster is smaller than the distance to the centroids of all the other clusters (Paal & Kolodyazhnyi 1983, Paal 1994): ...
... I 1 is the sum of square distances between the centroid of a united complex of two clusters, I 2 is the sum of square distances between the sample plots and their cluster centroids after dividing the complex into two suboptimal parts, x i is vector of OUT x i , m is vector of the centroid of the united complex, m i is vector of the cluster X centroid, d is dimensionality of the united complex, d = min(q, n – 1), where q and n are the number of characters and specimens in the united complex, respectively. To acquire a better interpretation of the estimates , it is more convenient to use correponding probabilities called coefficients of indistincness (CI) instead of the direct values (Paal 1987Paal , 1994): ...
Morphological variation of Saussurea esthonica Baer ex Rupr. and S. alpina (L.) DC. s. str. was studied with different multivariate methods. The most important characters supporting the clustering of the specimens into groups are the shoot hight and characters correlated to it, and hairiness of leaves, while the type of trichomes in both taxa is the same. Hence, these characters depend very much on ecological conditions and are, therefore, taxonomically not reliable enough. It appeared also that several specimens were morphologically intermediate between typical representatives of S. esthonica and S. alpina s.str. Therefore, we consider it more appropriate to treat these taxa as ecogeographical subspecies: S. alpina subsp. esthonica (Baer ex Rupr.) Kupff. and S. alpina subsp. alpina. Chromosome numbers established for S. alpina subsp. esthonica are 2n = 52, 54.
... Seepärast peaksid suktsessioonilisi protsesse uurivad välieksperimendid toimuma eeskätt selles mõõtkavas (Норин, 1979;Werffeli et al., 1997;Decocq, 2002;Paal & Degtjarenko, 2015). Boreaalsetes kuivades metsades jääb sünuuside ja/või mikrotsönooside pindala enamasti 0,1-10 m 2 piiresse, näiteks Lõuna-Eestis kasvavates pohla kasvukohatüüpi kuuse-männi segametsades on samblarinde sünuuside läbimõõt 0,3-1,4 m (0,1-2,1 m 2 ) (Paal, 1994). Erinevates kasvukohatüüpides võib sünuuside ja mikrotsönooside pindala muidugi küllaltki ulatuslikult varieeruda, ent käesoleva uurimuse kontekstis on oluline see, et üks 16 m 2 suurune analüüsiruut võib hõlmata vaid mõnda sünuusi või mikrotsönoosi ning ei saa seega pakkuda rahuldavat ülevaadet kogu metsakoosluse alustaimestust. ...
The changes in tree layer saplings, shrub, field and moss layer in Järvselja Nature Reserve virgin forest compartment (JS226) were analysed on the ground of data collected in 1955, 1985, 1993 and 2012. Four forest stands (sub-compartments) were studied; in every stand one 4 x 4 m sample area was established: area A1 represented Hepatica nobilis and Anemone nemoralis dominanted spruce stand, area A3 – drained transitional mire pine forest, area A4 – Mercurialis perennis-rich spruce stand and area A5 – Hepatica nobilis and Anemone nemoralis dominanted aspen stand. The number of tree layer saplings and shrub layer stems, as well as their species content have changed largely in all sample areas, being a bit more stable only on area A1. In field layer the abundance of initial dominant species changed remarkably in all areas or were replaced by other species in the course of succession. Changes in moss layer were the most striking in drained transition mire forest (area A3), where Pleurozium schreberi, Sphagnum centrale and S. capillifolium dominating in 1955 were replaced by S. centrale in 1993. The experiment planning in the current study is regrettably insufficient: to study forest communities succession using only one 4 x 4 m sample area in every stand does not allow to gather representative data about the vegetation structure and its variation limits. Moreover, in that way it is not possible to separate the timeinduced successional trend from the drainage impact that has an obviously prevailing importance in forest compartment JS226 being surrounded by ditches. © 2015 Estonian University of Life Sciences. All rights reserved.
Estonia is rich in wetlands - 16 500 mires larger than 1 ha are found on a land surface area of 47 450 sq. km. Mires with a peat deposit layer thicker than 30 cm cover 21.5% of the country. In studies of mire biodiversity five levels can be distinguished: population, species, coenotic, ecosystem, and landscape level. In Estonian mire studies the multilevel approach has proved to be especially important and productive. In the history of Estonian mire classification five stages can be identified: 1. in the beginning of this century, it was based on developmental stage and trophicity; 2. when water conditions were recognized as the main factor influencing mire formation, it became based on hydrochemical conditions and water sources; 3. with the use of vegetation mapping, geobotanical studies and aerial surveying, the prevailing vegetation layer became the best suitable basis; 4. next, a landscape structure approach was developed, where every mire site was treated as a complex of microsites and described on the basis of its components (tussocks, hummocks, hollows etc.); 5. recently, a combined approach, a universal habitat site type classification in which topography, soil, water regime and species composition of communities are all considered, has been elaborated. Estonian wetlands constitute 8 site type classes, 20 site type groups, and at least 107 community types.
The multivariate structure of the Scutellinla umbrorum complex (feuzales, Ascomycetes), based on the morphometrical parameters of 81 specimens from five ecotopes in the Netherlands, was analysed. According to conventional expert estimation, five putative taxa resp. species were established: S. patagontca (Rehm) Gamundi, S. aff. subhirtella Svrček, S. umbrorum (Fr.) Lambotte, S. parvispora J. Moravec and S. subhirtella s. Kullman. These taxa form a taxonomic continuum hardly separable by traditional taxonomy. Five clusters obtained by UPGMA (with the generalized J-distance for mixed data as a measure of resemblance) are more distinct and in good accordance with ecological factors; some of them, however, are statistically not well separated. The revision of the clusters' structure by k-means approach yields highly discontinuous clusters. The morphometric characters of specimens differ when going from open habitats to the forest. Differences are also revealed in phenology: the growing season starts in the forest later than in open habitats. The data are divided into two subsets according to spore ornamentation and spore width, the withingroup variation of either subset is caused mainly by the length of marginal hairs. On the basis of several statistical methods a supposition was introduced that the S. umbrorum complex probably consists of two polymorphic species, S. umbrorum (Fr.) Lambotte and S. subhirtella Svrček s.l., with the mean value of marginal hairs longer than 450 μm and shorter than 450 μm, respectively. The UPGMA clusters can be interpreted as ecodemes of respective species.
23 widespread apomictic Alchemilla microspecies occurring in Estonia are analyzed to investigate whether the species and higher rank taxa are distinct, how variable these taxa are and which characters distinguish them better. Cluster analysis, discriminant analysis, analysis of variance, principal component analysis and continuum analysis are used for data processing. The characters form four correlative groups, describing (i) vegetative and (ii) generative parts of the plant body, (iii) hairiness characters and, (iv) leaf teeth measurements. The best characters according to analysis of variance for disünguishing species are hairiness characters, but often they distinguish only few species very clearly and cannot be used for the remaining ones. Hence the other characters cannot be excluded. From the studied species only A. plicata, A. semilunaris and A. lindbergiana are significantly distinct from all others. The remaining ones form a complicated network of mutually indistinct pairs. Higher rank taxa — sections and series according to Rothmaler, Fröhner and Yuzepchuk are better separated, containing very few mutually indistinct pairs. Results from species centroids' clustering are most congruent with Fröhner's system, but still some changes seem to be necessary and a corrected system is proposed here. Section Plicatae is split into two series: Pubescentes and Barbulatae, sections Alchemilla, Ultravulgares and Decumbentes are joined as three series of section Hirsutae, and A. filicaulis is moved from section Plicatae to section Coriaceae. Coriaceae should also be split into three series: Exuentes (A. filicaulis), Glabricaules (A. glabricaulis) and Coriaceae (other species).
Morphological variation ofPotentilla norvegica L.,P. heidenreichii
Zimmeter andP. supina L. usually treated within the sectionRivales
Wolf,P. recta L. (sect.Rectae
Wolf),P. canescens
Bess.,P. argentea L. s.l.,P. collina
Wibel (sect.Argenteae
Wolf) andP. goldbachii
Rupr. (sect.Chrysanthae
Wolf) was studied using multivariate statistical methods. According to k-means clustering,P. canescens stands closer toP. heidenreichii of the sect.Rivales than toP. argentea. P. collina, the other representative of sect.Argenteae, is not connected withP. canescens at all. Therefore,P. canescens should belong to sect.Rivales and not to sect.Argenteae.
InPotentilla argentea s.l.,P. impolita
Wahlenb.,P. argentea L. var.argentea, var.decumbens (Jord.)Lehm., var.demissa
(Jord.) Lehm., var.grandiceps
(Zimmeter) Rouy etE.G. Camus and var.tenerrima
(Velen.) Wolf were identified.P. impolita specimens did not cluster out into a separate cluster as didP. collina, P. canescens andP. heidenreichii, but formed mixed clusters with different varieties ofP. argentea s.str. Therefore,P. impolita is not worthy of the rank of species and evidently not even that of subspecies, and should be treated as a variety—P. argentea var.incanescens
(Opiz) Focke.
Nine Estonian Alchemilla species belonging to the sections Ultravulgares and Alchemilla, or considered being close to them, were analysed. When the analysed specimens were divided into sections, the latter were statistically distinct and formed separable groups in the character space. When the specimens were grouped on a species level, A. cymatophylla, A. subcrenala and A. heptagona were insignificantly distinct, but, in the character space, specimens of A. heptagona were visually well distinguished from the other two. Specimens of A. acutiloba, A. micans, and A. xanthochlora formed confidently distinct (p < 0.01) species-clusters, but at the same time they formed a joint cloud in the character space, indicating the compactness of section Alchemilla. Specimens of A. semilunaris were close to A. lindbergiana, and not, as has previously been supposed, to the section Ultravulgares. A. semilunaris should possibly be kept in a separate section Decumbentes. Specimens of A. lindbergiana were on one hand close to A. semilunaris. on the other hand close to the species of section Alchemilla; including it in the latter section is still doubtful. A. subglobosa was indistinct from A. subcrenata but could generally be separated from sections Alchemilla and Ultmvulgares. Of the 41 tested characters, 35 were useful for species discrimination; counts, nominal and ratio characters were better than metric ones. According to the cluster analysis, specimens of A. acutiloba and A. micans formed one big cluster, all other specimens belonged to another.
The understory vegetation (vascular plants, bryophytes and lichens) in an area dominated by boreal coniferous forests is subjected to detailed ecological analysis. Two hundred meso sample plots (1 m ² ) are used as basis for vegetation sampling, and provided with measurements of 33 environmental variables. Species abundance is recorded as frequency in 16 subplots. Parallel DCA and 2-dimensional LNMDS ordinations of meso sample plots were largely identical, both provided two coenocline axes interpretable in ecological terms. The first axis is interpreted as the response to a broad-scale topographical complex-gradient, made up of two independent complex-gradients; (1) a topography-soil depth complex-gradient in the pine forest (running from lichen-rich pine forests to submesic Vaccinium myrtillus-dominated spruce forests), and (2) a complex-gradient in soil nutrient status in the spruce forest. The second axis, mainly affecting the species composition of the bottom layer, is interpreted as a fine-scale paludification gradient. The causes of variation along these gradients are discussed: Desiccation tolerance is considered to act directly on the physiology of vascular plant species, setting their limits towards xeric sites. Similarly, cryptogams with optima in the more mesic sites are considered to be excluded from drier sites by physiological tolerance. Limits of cryptogams towards more mesic sites are, however, considered to be set by competitive ability (growth rates) in accordance with the competitive hierarchy theory. N availability is assumed to be the most important factor for differentiation of vascular plants along the nutrient gradient, while bryophytes are expected to respond to a complex of factors, including structural properties of the humus layer. Increasing N accumulation in the humus towards xeric sites may indicate oversaturation due to deposition of airborne NO 3 - or NH> 4 ⁺ . Fine-scale paludification, mainly of a soligenous type, occurred in sloping terrain with shallow soil. The cryptogams apparently make up a competitive hierarchy also along the paludification gradient. No other coenoclines could be identified by analysis of 0.0625 m ² micro sample plots, most probably because the response of vegetation to micro-scale environmental gradients (probably most important: the variation in microtopography) not essentially different from the meso-scale gradients, and because the importance of random processes increase towards finer scales. Structuring processes are discussed with reference to the observed patterns. The lack of a closed bottom layer in almost all sample plots is considered a strong indication of high importance of fine-scale disturbance and density-independent mortality in the investigated system, while interspecific competition is of lower importance. The methodology in vegetation ecological studies is discussed with particular reference to monitoring. The potential of an integrated concept using permanent plots, parallel investigation of vegetation and environmental parameters, and gradient analysis, is stressed. Several suggestions for future studies, based on this integrated approach, are made.
In recent years there has been a considerable controversy over the relative merits of classification and.ordination in the study of vegetation.Classification implies the division of the individuals or units being classified into categories or classes, whose members show a greater or less degree of similarity a-mongst themselves, and differ from members of other categories. Ordination (whose development is associated particularly with the name of J.T. CURTIS and his school in Wisconsin) treats the vegetation being studied as a continuum, and seeks to arrange the stands so that their spatial relation to one or more axes will display as much information as possible about their relationships. This controversy has become associated with, and to a large extent heir to, an older controversy — that between those who (like CLEMENTS) held a pseudo-organismal concept of the plant community, and those who (like GLEASON) held that a plant community is a fortuitous aggregation of plants separately dependent on the factors of the environment.
A Vegetation surveyor meets with three Categories of boundaries:
(1)
concrete discontinuities in the field
(2)
abstract boundaries between classification units
(3)
lines on a map (Cartographic boundaries)
Nanocyperion communities (s.l.) are considered here as “warp-and-woof” communities; the Nanocyperion components are described separately as synusiae. On the Netherlands Frisian Islands, four main synusiae have been recognized. Raunkiaer life form spectra show few differences between the communities. Life strategy spectra of the Nanocyperion synusiae, based on systems for phanerogams (modified after Bakker 1966) and bryophytes, yield the clearest patterns. A comparison of the ecology of the communities and an interpretation of the spectra in terms of avoidance of stress or competition suggest that inundations and standing crop of the communities are the main factors determining the distribution of the synusiae. Winter inundations overrule the influence of differences in productivity level, which becomes prominent in drier situations.