Finding a common ordination for several data sets by individual differences scaling

Individual differences scaling is a multidimensional scaling method for finding a common ordination for several data sets. An individual ordination for each data set can then be derived from the common ordination by adjusting the axis lengths so as to maximize the correlations between observed proximities and individual ordination distances. The importance of the various axes for each data set and the mutual similarities and goodness of fit for the individual data sets are described by weight plots. As an example, 46 soft-water lakes in eastern Finland are ordinated on two dimensions according to 3 chemical data sets (water in summer and autumn, sediment) and 4 biological sets (major phytoplankton groups, phytoplankton, surface sediment diatom and cladoceran assemblages). The method seems to be effective as a means of ordination for obtaining the common ordination for the data sets. The major taxonomic groups gave the ordination which differed most clearly from the ordinations of the other data sets. Phytoplankton was most poorly ordinated in all the analyses. The other data sets were fairly coherent. When only biological data sets were ordinated, the diatoms and cladocerans showed rather different patterns. It seems that the cladocerans are best correlated with water chemistry, both according to weights in the joint analysis, and according to correlation between the axes from the biological data sets and the chemical variables.Abbreviations CCA = Canonical correspondence analysis - IDS = Individual differences scaling - MDS = multidimensional scaling - PCA = Principal components analysis     

Adaptive behavior with protozoa-inspired dynamics

A protozoa-inspired system for controlling autonomous robots is explained. The proposed system uses the nonlinear dynamics of the molecule concentrations in the cytoplasm of a protozoan. The model includes many parameters which are optimized using the genetic algorithm. A mobile robot obstacle avoidance example is shown with simulation results. The proposed protozoa-inspired system opens interesting possibilities to create new species by combining individual models by symbiotic or colony relationships. Received: 13 March 1996 / Accepted in revised form: 17 July 1998     

Enzymatic transfer of a {beta}1,6-linked N-acetylglucosamine to the {alpha}-galactose of globo-N-tetraose: in vitro synthesis of a novel hybrid pentasaccharide of lacto-globo type

A novel saccharide was synthesized by incubating globo-N-tetraose,GalNAcß1–3Gal     

Gap felling as a forest harvesting method in boreal forests: responses of carabid beetles (Coleoptera, Carabidae)

In order to study the ecological effects of logging combined with mechanical soil preparation, we sampled carabid beetles with pitfall trapping in nine spruce-dominated stands in central Finland in 1995–1998. Three of the stands were left intact as controls. Three 1600-m² openings per stand were logged in the winter 1995–1996 into six stands. In three of these stands, light soil preparation was applied. Logging affected the species assemblages, but soil preparation per se had no clear effects. Open-habitat species increased in abundance in the openings one year after logging, but catches of generalist species in the different treatments did not differ from each other. A forest species, Calathus micropterus , was least abundant in the prepared openings. The amounts of logging residue, exposed mineral soil and aggregated humus, as well as the abundance of red wood ants, significantly explained variation in carabid assemblages.     

Indirect emissions of forest bioenergy: detailed modeling of stump‐root systems

Indirect carbon dioxide emissions from producing bioenergy from tree stumps and roots depend critically on the decomposition rate of these harvest residues if they were left in forest to decay. We developed a method to improve the current estimates of these emissions. First, the 3D structure of uprooted stump‐root systems was modeled based on terrestrial laser‐scanning data. Second, information obtained on the size distribution of the stumps and the roots was used to simulate their decomposition and to estimate the indirect emissions. The method was able to describe the structure of stump‐root systems at a clear‐cut boreal Norway spruce test site. Compared with earlier results based on the diameter of stumps alone, the new estimates of the decomposition rate were slightly higher and, consequently, those of the indirect emissions slightly lower. The method is useful to collect information on the indirect emissions of stump‐root bioenergy quickly in different forests.     

Modeling Soil Carbon Dynamics in Northern Forests: Effects of Spatial and Temporal Aggregation of Climatic Input Data

Boreal forests contain 30% of the global forest carbon with the majority residing in soils. While challenging to quantify, soil carbon changes comprise a significant, and potentially increasing, part of the terrestrial carbon cycle. Thus, their estimation is important when designing forest-based climate change mitigation strategies and soil carbon change estimates are required for the reporting of greenhouse gas emissions. Organic matter decomposition varies with climate in complex nonlinear ways, rendering data aggregation nontrivial. Here, we explored the effects of temporal and spatial aggregation of climatic and litter input data on regional estimates of soil organic carbon stocks and changes for upland forests. We used the soil carbon and decomposition model Yasso07 with input from the Norwegian National Forest Inventory (11275 plots, 1960–2012). Estimates were produced at three spatial and three temporal scales. Results showed that a national level average soil carbon stock estimate varied by 10% depending on the applied spatial and temporal scale of aggregation. Higher stocks were found when applying plot-level input compared to country-level input and when long-term climate was used as compared to annual or 5-year mean values. A national level estimate for soil carbon change was similar across spatial scales, but was considerably (60–70%) lower when applying annual or 5-year mean climate compared to long-term mean climate reflecting the recent climatic changes in Norway. This was particularly evident for the forest-dominated districts in the southeastern and central parts of Norway and in the far north. We concluded that the sensitivity of model estimates to spatial aggregation will depend on the region of interest. Further, that using long-term climate averages during periods with strong climatic trends results in large differences in soil carbon estimates. The largest differences in this study were observed in central and northern regions with strongly increasing temperatures.     

Does removal of an alien predator from small islands in the Baltic Sea induce a trophic cascade?

Changes in carnivore abundance can alter the distribution and abundance of plants on a community wide basis, an effect known as a trophic cascade. Because alien predators can have a disproportionate impact, compared to native predators, on herbivore populations, they may induce stronger trophic cascades in plant communities than native predators. We studied the indirect effects of the removal of an alien predator, the American mink Mustela vison on plant communities on small islands in the Baltic Sea, SW Finland. Mink had been removed from a group of islands for 12 yr, while another group of islands with mink presence served as a control area. Field voles Microtus agrestis and bank voles Myodes glareolus exert strong grazing pressure on the island vegetation and are an important part of mink diet. On nine islands of the mink removal area and five islands of the control area we studied the vegetation in ten randomly chosen plots; five in herbaceous and five in woody (i.e. dwarf shrub) vegetation. We studied the cascading impacts of mink predation on grassy and woody vegetation using the Shannon diversity and equitability indices and comparing abundances of different species between mink removal and control islands. Diversity and equitability of plant communities were higher on mink removal islands. In grassy patches, abundances of several species differed between mink removal and control islands. Our results demonstrate, for the first time, that alien predator removal may induce a trophic cascade on small islands.     

The macrophyte, Stratiotes aloides, protects larvae of dragonfly Aeshna viridis against fish predation

Predation could be one force determining which contemporary species occupy a certain habitat. Aeshna viridis is an endangered dragonfly species with a larval distribution strongly associated with lakes where the water plant, water soldier, Stratiotes aloides, occurs. In this study, the larvae were almost exclusively found in patches of S. aloides. To study larval association with S. aloides further, we conducted a series of laboratory experiments. Behavioural experiments indicated that larvae preferred S. aloides. Aeshna viridis larvae were nocturnal and rather inactive. Larvae on S. aloides were less susceptible to predation by the perch, Perca fluviatilis, than larvae on another water plant, Myriophyllum alterniflorum. According to our study it seems that occurrence of S. aloides may limit the distribution of A. viridis, and the protection of refuges may be essential in planning the conservation of this endangered species.     

Topographic and altitudinal patterns in plant communities on European arctic islands

 Vegetation on Bear Island, Jan Mayen and Spitsbergen was investigated along altitudinal and topographic gradients in order to describe the main patterns in plant community distributions and compare them with those on the mainland. In a numerical classification the communities were distinctly differentiated; however, physiognomically similar Racomitrium and Sanionia communities dominated in most habitats on Bear Island and Jan Mayen. On Spitsbergen, moss-dominated communities prevailed in depression sites. High-altitude sites were occupied either by moss-dominated communities or by variable assemblages of fragmented moss cover and scattered vascular plants. Dwarf shrub and grass heaths that were common on the mainland did not occur on grazer-free Bear Island and Jan Mayen, and were confined to the lowest altitudes on Spitsbergen. The lack of grazers on Bear Island and Jan Mayen accounts in part for the differences in vegetation between the mainland and the islands. Received: 13 December, 1995/Accepted: 13 March, 1996