Parametric analysis of radial increment of Scots pine for environmental assessment

Tjarve D., 2013. Parastās priedes radiālā pieauguma parametriska analīze vides izmaiĦu noteikšanai. Darbā analizēta parastās priedes (Pinus sylvestris L.) piemērotība dendroekoloăiskam vides kvalitātes novērtējumam. Izstrādāta jauna metode izkritušo un papildus gadskārtu meklēšanai. Noskaidrota piecu dendrohronoloăijā biežāk izmantoto modeĜu atbilstība priedes gadskārtu sērijām. Secināts, ka vides kvalitātes novērtējumam piemērotas ir trīsdesmitgadīgas un vecākas gadskārtas. Pārbaudītas vairākas datu transformācijas un izlīdzināšanas metodes. Vides kvalitātes novērtējuma metode pārbaudīta 40 vietās visā Latvijas teritorijā, kā arī 24 vietās Skrundas apkārtnē. Lielākajā daĜā paraugu Ħemšanas vietu Skrundas apkārtnē konstatēta būtiska un ilgstoša priežu pieauguma samazināšanās, kas liecina par kāda nozīmīga ārēja faktora ietekmi. Iespējams, tas saistīts ar bijušās Skrundas radiolokācijas stacijas elektromagnētisko starojumu. Atslēgas vārdi: koku gadskārtas, šėērsdatēšana, augšanas modeĜi, Pinus sylvestris, dendroekoloģija, metodes.Tjarve D., 2013. Parametric analysis of radial increment of Scots pine for environmental assessment. The suitability of Scots pine (Pinus sylvestris L.) for the dendroecological assessment of environmental quality was analysed. A new method for the detection of missing and false tree-rings was developed. Five of the most frequently used growth models were fitted to the individual tree-ring series. It was concluded that thirty years and older tree rings are the best use for environmental quality assessment. Several methods of data transformation and smoothing were tested. Method was tested in 64 sample plots selected across a territory of Latvia, including 24 sample plots in surrounding of Skrunda town. In the most plots in Skrunda, a significant and permanent decrease of the growth increment was found. It indicates the presence of strong negative environmental factor. Possibly it is the impact of Skrunda radiolocation station. Keywords: tree-rings, crossdating, growth models, Pinus sylvestris, dendroecology, methods

Pflanzengesellschaften der Graudünen (Koelerio-Corynephoretea) an der Ostseeküste in Lettland

The grey dunes along the present-day depositional coasts of Latvia are among the most diverse dune ecosystems in the Baltic Sea region. This paper focuses on the grey dune plant communities, their classification based on the Braun-Blanquet approach and their ecology and distribution in Latvia. A total of 3,430 phytosociological relevés were sampled in all coastal sections in the period from 1994 to 2008. The vegetation was classified using TWINSPAN analysis. Diagnostic species were determined for each syn taxon using statistical measures of fidelity (phi coefficient and Fishers exact test). The phytogeography of associations and variants is described on the basis of a distribution range analysis of plant species. In total, three associations of the class Koelerio-Corynephoretea occur in the grey dunes. The Corniculario aculeatae-Corynephoretum canescentis and the Caricetum arenariae belong to the alliance Corynephorion canescentis and the order Corynephoretalia canescentis. The Festucetum polesicae belongs to the alliance Koelerion glaucae in the order Sedo acris-Festucetalia. With six variants, it is the phytosociologically most diverse association of the grey dunes: typical variant, variant of Gypsophila paniculata, variant of Koeleria glauca, variant of Thymus serpyllum, variant of Epipactis atrorubens and variant of Corynephorus canescens. Our results show phytosociological differences among five coastal sections due to geomorphology and coastal processes. The most diverse grey dune plant communities occur on the open Baltic Sea coast where all three associations are represented. The most common vegetation type on all coastal sections in Latvia is the typical variant of the Festucetum polesicae. The Epipactis atrorubens variant of this association is widely distributed, too. It has its major occurrences along the Gulf of Riga and the Irbe Strait. The Corniculario aculeatae-Corynephoretum canescentis was found in only two locations. Stands of the Festucetum polesicae var. Koeleria glauca occupy wider areas on old dunes, while the Festucetum polesicae var. Gypsophila paniculata is more typical on young dynamic dunes with intensive sand drift. The results of the phytogeographical analysis of vegetation data show that under the influence of climate, especially with dominance of the oceanic and transformed oceanic air masses, grey dune plant communities on the Latvian coast are mainly sub-oceanic to sub-continental. The most continental community is the Festucetum polesicae var. Koeleria glauca, while the Caricetum arenariae and the Corniculario aculeatae- Corynephoretum canescentis have the strongest oceanic character.Die naturräumliche Ausstattung Lettlands mit ihren Anlagerungen und Umlagerungen von Sand an den Küsten sowie verschiedenen Klimabedingungen und früheren Landnutzungsformen ist ein Grund dafür, dass die Graudünen von Lettland zu den vielfältigsten Dünenökosystemen der Ostseeküste zählen. In diesem Artikel sind die Forschungsergebnisse über die Pflanzengesellschaften der Graudünen Lettlands zusammengefasst. Im Zeitraum 1994-2008 wurden in typischen Graudünengebieten entlang der Küste von Lettland 3.430 pflanzensoziologische Aufnahmen nach der Braun-Blanquet-Methode erstellt. Die Aufnahmen wurdem mit TWINSPAN klassifiziert. Diagnostische Arten der herausgearbeiteten Einheiten wurden anschließend mittels statistischer Treuemaße (phi-Koeffizient, Fishers exakter Test) ermittelt. Die phytogeographische Analyse der Assoziationen und Varianten wurde auf Grundlage der Artenzusammensetzung der Vegetation vorgenommen. Insgesamt kommen drei Assoziationen aus der Klasse Koelerio-Corynephoretea in den Graudünen vor. Das Corniculario aculeatea-Corynephoretum canescentis und das Caricetum arenariae gehören zum Verband Corynephorion canescentis in der Ordnung Corynephoretalia canescentis. Das Festucetum polesicae wird zum Verband Koelerion glaucae in der Ordnung Sedo acris-Festucetalia gestellt. Mit 6 Varianten (Typische Variante, Gypsophila paniculata-Var., Koeleria glauca-Var., Thymus serpyllum-Var., Epipactis atorubens-Var. und Corynephorus canescens Var.) ist die vielfältigste Assoziation der Graudünen. Der Vergleich von fünf geomorphologisch und landschaftlich unterschiedlichen Küstenabschnitten zeigt, dass die Vielfältigkeit der Graundünengesellschaften an der offenen Ostseeküste mit Vorkommen aller drei Assoziationen am höchsten ist. Die häufigste Pflanzengesellschaft an der ganzen Ostseeküste ist die Typische Variante des Festucetum polesicae. Weit verbreitet ist auch die Epipactis atrorubens-Variante des Festucetum polesicae, die an der Ostseeküste des Meerbusens und der Meeresenge von Irbe festgestellt wurde. Die Verbreitung des Corniculario aculeatae-Corynephoretum canescentis, das nur an zwei Orten vorkommt, ist durch einen Mangel an Störungen eingeschränkt. Das Festucetum polesicae in der Variante von Koelerio glauca ist in den älteren Graudünen am häufigsten, während die Variante Gypsophila paniculata vor allem in Bereichen mit stärkeren Sandverwehungen auftritt. Die Ergebnisse der phytogeographischen Analyse zeigen, dass die Graudünengesellschaften in Lettland vorwiegend subozeanisch bis subkontinental, das Caricetum arenariae und das Corniculario aculeatae-Corynephoretum canescentis sind dagegen am stärksten ozeanisch geprägt

Arbuscular mycorrhizal colonization in roots of sand dune plants in relation to soil factors

Abstract Seacoast plant communities represent primary successions characterized by a harsh environment in which mycorrhizal symbioses are known to be important for plant survival and growth. The study was carried in two grey dune areas (Užava and Pāvilosta) on the western coast of Latvia by the Baltic Sea. We examined how root colonization and abundance of arbuscular mycorrhiza differed along a primary dune succession from an early successional primary dune to an overgrowing grey dune, in relation to soil factors. We hypothesized that plant species growing on soil with a poorly developed soil horizon and low C, P and N concentration would have a higher extent of arbuscular mycorrhiza colonization. We also tested the relationship of soil factors and fungal abundance in roots within specific plant species. In a total of 93 plots among 5 habitats, we determined soil carbon, phosphorus and nitrogen concentrations and sampled roots of dominant plants for determination of arbuscular mycorrhizal (vesicules and hyphae) frequency, abundance of arbuscular mycorrhizal vesicules and hyphae, and abundance of arbuscules. The results showed that extent of mycorrhizal colonization was related to soil development, being more important in the most nutrient poor habitats, compared to grassland habitats. However, slight increases in P and N concentration were associated in increased mycorrhizal colonization in early successional stages and disturbed habitats