0000000000034446
AUTHOR
Guntis Tabors
showing 7 related works from this author
Age and spatial structure of natural Pinus sylvestris stands in Latvia
2005
Abstract The age and spatial structure of six natural old growth Pinus sylvestris stands in Latvia were investigated, to attempt to identify retrospectively the past features of development. In each stand, one or two plots of size 200–900 m2 were established. Tree locations were mapped, stem diameter was measured, and tree age was determined from cores or by counting branch whorls. Tree distribution was assessed by Ripley's K function. A clumped spatial pattern was shown for P. sylvestris younger than 100 years. The temporal patterns of establishment could be partly linked to favourable climatic periods. The major disturbance affecting pine stands along the coast was windblown sand, which p…
Use of an artificial model of monitoring data to aid interpretation of principal component analysis
2000
Abstract An artificial data matrix of element concentrations at sampling locations was created which included six simulated gradients of correlated variables (Ca+Mg, Ni+V, Pb+Cu+Zn, Cd, Fe and K), representing a simplified model of a National survey. The data matrix model was used to explore the efficiency with which Principal Components Analysis (PCA), without and with Varimax rotation, could derive the imposed gradients. The dependence of PCA on outliers was decreased by log-transformation of data. The Components derived from non-rotated PCA were confounded by bipolar clusters and oblique gradients, both resulting in superimposition of two independent gradients on one Component. Therefore…
Monitoring seasonal changes in microbial populations of spruce forest soil of the Northern Temperate Zone
2012
Soil microbial populations in the Northern Temperate Zone have been poorly studied in comparison with extreme environments. The aim of the work was to study the seasonal changes in the microbial populations of spruce forest soil of the Northern Temperate Zone using classical methods of microbiology and molecular biology. Upper horizons in two Picea abies stands on sod- podzolic and illuvial humus podzol soil were analysed. Sampling was done monthly over a period of twelve months (May 2009-April 2010). Microbial communities in both experimental plots showed different responses to the analysed environmental factors. In the sod-podzolic soil only the fungal DNA amount was significantly higher …
Teaching Green Analytical Chemistry on the Example of Bioindication and Biomonitoring (B & B) Technologies
2019
Teaching of Green Analytical Chemistry (GAC) requires a not inconsiderable willingness on the part of the lecturer to familiarize himself with a relatively new field in analytical chemistry. Although there is much that can be derived from Green and Sustainable Chemistry, the GAC’s forward-looking perspectives in particular are independent approaches that must not be neglected. In the first chapter of this article, approaches are pursued “how (teachers) learn to learn,” ultimately based on a consensus on ethics, which allows dealing with people, society and the environment to become an interdisciplinary unit. The end of all this is a smart method of conflict management which provides solutio…
Dynamics of natural hemiboreal woodland in the Moricsala Reserve, Latvia: the studies of K. R. Kupffer revisited
2010
Abstract Karl Reinhold Kupffer (1872–1935), an outstanding botanist and plant ecologist, took the initiative that led to the establishment of the first nature reserve in Latvia, on Moricsala Island in 1912. The reserve provided an excellent reference area for natural hemiboreal woodland for future generations. There have been very few studies on the dynamics of natural broadleaved forest in Europe, probably owing to lack of primeval forests of this type. However, Kupffer produced a map of forest types in the reserve with accurate descriptions of the vegetation by layers, and his descriptions include interpretations of forest dynamics processes. This information, together with the present ag…
Country-specific correlations across Europe between modelled atmospheric cadmium and lead deposition and concentrations in mosses
2012
Previous analyses at the European scale have shown that cadmium and lead concentrations in mosses are primarily determined by the total deposition of these metals. Further analyses in the current study show that Spearman rank correlations between the concentration in mosses and the deposition modelled by the European Monitoring and Evaluation Programme (EMEP) are country and metal-specific. Significant positive correlations were found for about two thirds or more of the participating countries in 1990, 1995, 2000 and 2005 (except for Cd in 1990). Correlations were often not significant and sometimes negative in countries where mosses were only sampled in a relatively small number of EMEP gr…
Promocijas darbs
2007
Jau iepriekš ir bijuši eksperimentālie pētījumi, kuros tika mērītas sūnas un novērtēts to pieaugums, tomēr savā promocijas darbā realizēju sūnu skenēšanas metodes aprobāciju. Sūnu skenēšanas metode tika veikta tāpēc, lai turpmākos pētījumos nevajadzētu veikt katra sūnas segmenta atsevišķu parametru (segmenta stumbra un zaru) mērīšanu, kas ir laika un darba ietilpīgs process. Veicot Hylocomium splendens skenēšanas efektivitates novērtēšanu secināts, ka segmenta virsmas laukums būtiski korelēja ar segmentu svaru un arī ar zaru garumu, bet nebūtiska korelācija bija ar sūnas segmentu stumbra mērījumiem. Pēc sūnas dinamikas pētījuma rezultātiem acīmredzot varētu ieteikt sūnu bioindikācijai ņemt …