Masked blindsight in normal observers: Measuring subjective and objective responses to two features of each stimulus.

Recent visual masking studies that have measured visual awareness with graded subjective scales have often failed the show any evidence for unconscious visual processing in normal observers in a paradigm similar to that used in studies on blindsight patients. Without any reported awareness of the target, normal observers typically cannot discriminate target's features better than chance. The present study examined processing of color and orientation by measuring graded awareness and forced-choice discriminations for both features in each trial.

Genetic and environmental factors behind foliar chemistry of the mature mountain birch.

Previous studies of mountain birch (Betula pubescens spp. czerepanovii) repeatedly have found differences between individual trees in herbivory-related traits, but rarely have yielded estimates of the additive genetic variation of these traits or of their relationship to habitat. We used thirty-year-old birch half-sibs in a northern common garden to estimate the effect of genetics and local microhabitat on resistance-related traits.

Interactions of ectomycorrhizas and above-ground insect herbivores on silver birch.

Mycorrhizas are mostly beneficial to host plant growth and survival, e.g., due to improved water and nutrient uptake and enhanced pathogen protection, but also a significant amount of host plant carbon is allocated below-ground to support the mycorrhizal growth.

Extensive tree health monitoring networks are useful in revealing the impacts of widespread biotic damage in boreal forests.

We surveyed the regional distribution of conifer defoliation in Finland with an extensive monitoring network during 1995-2006 (EU Forest Focus Level I). The average defoliation in the whole Finland was 10.3% in pine and 19.

Mechanical-statistical modeling in ecology: from outbreak detections to pest dynamics.

Knowledge about large-scale and long-term dynamics of (natural) populations is required to assess the efficiency of control strategies, the potential for long-term persistence, and the adaptability to global changes such as habitat fragmentation and global warming. For most natural populations, such as pest populations, large-scale and long-term surveys cannot be carried out at a high resolution. For instance, for population dynamics characterized by irregular abundance explosions, i.

The significance of ectomycorrhizas in chemical quality of silver birch foliage and above-ground insect herbivore performance.

We tested whether the ectomycorrhizal (ECM) infection level of roots of silver birch (Betula pendula) affects performance of above-ground insect herbivores by increasing available plant biomass, by enhancing availability of nutrients, or by modifying concentration of defense compounds, i.e., phenolics, in birch foliage.

Environmental changes in the North Atlantic Region: SCANNET as a collaborative approach for documenting, understanding and predicting changes.

The lands surrounding the North Atlantic Region (the SCANNET Region) cover a wide range of climate regimes, physical environments and availability of natural resources. Except in the extreme North, they have supported human populations and various cultures since at least the end of the last ice age. However, the region is also important at a wider geographical scale in that it influences the global climate and supports animals that migrate between the Arctic and all the other continents of the world.

Reduction in size and fecundity of the autumnal moth, Epirrita autumnata, in the increase phase of a population cycle.

Increasing fecundity with increasing density has been observed for many cyclic herbivore populations, including some forest Lepidoptera. We monitored population density, body size and reproductive capacity of the cyclic lepidopteran, the autumnal moth (Epirrita autumnata, Geometridae), from the early increase phase to the devastating outbreak density in northernmost Norway. Larval density of the species increased exponentially from 1998 to 2002 and remained at the outbreak level also in 2003.

Performance of moth larvae on birch in relation to altitude, climate, host quality and parasitoids.

We studied topographical and year-to-year variation in the performance (pupal weights, survival) and larval parasitism of Epirrita autumnata larvae feeding on mountain birch in northernmost Finland in 1993-1996. We found differences in both food plant quality and parasitism between sites ranging from 80 m to 320 m above sea level. Variation in food plant quality had particularly marked effects on larval survival.

Birch family and environmental conditions affect endophytic fungi in leaves.

We investigated whether variation in foliar endophyte frequency among mountain birch trees from different maternal families was due in part to genetic differences among trees. The effect of different environmental conditions on the susceptibility of these mountain birch families to foliar endophytes was tested. The 3-year study was conducted in two tree gardens (altitudinal difference 180 m) with ten families of mountain birch.

Structure of a microbial community in soil after prolonged addition of low levels of simulated acid rain.

Humus samples were collected 12 growing seasons after the start of a simulated acid rain experiment situated in the subarctic environment. The acid rain was simulated with H2SO4, a combination of H2SO4 and HNO3, and HNO3 at two levels of moderate acidic loads close to the natural anthropogenic pollution levels of southern Scandinavia. The higher levels of acid applications resulted in acidification, as defined by humus chemistry.

Wood ants and a geometrid defoliator of birch: predation outweighs beneficial effects through the host plant.

Soil amelioration by a wood-ant species and its consequences for the larval performance of autumnal moths feeding on mountain birch were studied at various distances from the nest mound. Soil nitrate and ammonium nitrogen did not show any clear relationship with distance. However, trees growing in the mound had over 20% more foliar nitrogen than more distant trees.

Responses of ground vegetation to prolonged simulated acid rain in sub-arctic pine-birch forest.

The effects of prolonged simulated acid rain on percentage cover of ground vegetation, and on growth and reproduction of two dominating dwarf shrubs (Emapetrum nigrum and Vaccinium vaitisidaea) were examined in a field experiment in the Finnish Subarctic, in an area with low ambient levels of sulphur and nitrogen deposition. Acid rain treatments included moderate (pH 3.8) and high (pH 2.

The effect of simulated acid rain on the biochemical composition of Scots pine (Pinus sylvestris L.) needles.

The effects of prolonged simulated acid rain on the biochemistry of Scots pine needles were studied in Finnish Lapland. Pine trees were exposed by spraying the foliage and soil with either clean water or simulated acid rain (SAR; both sulphuric and nitric acids) over the period 1985-1991. The concentrations of carbohydrates (starch, glucose, fructose, sucrose) in one-year-old pine needles were not affected by SAR-treatments.

Decrease in feeding niche breadth of Melasoma lapponica (Coleoptera: Chrysomelidae) with increase in pollution.

We studied host-plant preference and performance of the leaf beetle, Melasoma lapponica, around Severonikel smelter situated in Monchegorsk, Russia. The breadth of feeding niche (Smith's measure) based on both field counts and preference tests decreased with an increase of ambient SO concentration, but showed no relationship with either metal pollutants or beetle population densities. In heavily polluted plots (mean annual SO concentrations 400-1000 μg/m) the beetles concentrated on Salix borealis, Whereas in moderately and slightly polluted plots they used other willow species as well.

The host-pathogen system of Gremmeniella abietina (Lagerb.) Morelet and Scots pine; effects of non-pathogenic phyllosphere fungi, acid rain and environmental factors.

Scots pine seedlings (1-yr-old) were inoculated either once, or three times, with the conidia of two saprophytic Honmmema species. After these inoculations, the seedlings were inoculated later with conidia of the pathogenic fungus Gremmeniella abietina (Lagerb.) Morelet.

Simulated acid rain affects birch leaf endophyte populations.

Endophytes were frequently isolated from mountain birch (Betula pubescens var. tortuosa (Ledeb.) Nyman) leaves at a subarctic site where natural air pollution is low.

Effects of larval age and prolonged simulated acid rain on the susceptibility of European pine sawfly to virus infection.

We studied the effect of simulated acid rain treatment of host trees on the susceptibility of the European pine sawfly larvae to virus, and possible differences when larvae of two different ages were infected. Older larvae were less susceptible to virus. Most larvae treated with virus 2 days after they started feeding on experimental foliage (group A) died rapidly within 10 days after the virus treatment, and survival to the end of the larval period was only 8-25%.

Simulated acid rain reduces the susceptibility of the European pine sawfly (Neodiprion sertifer) to its nuclear polyhedrosis virus.

The study dealt with the effect of simulated acid rain (both H(2)SO(4) and HNO(3); acidities of pH 4 and pH 3) on the susceptibility of the larvae of Neodiprion sertifer to its nuclear polyhedrosis virus. Scots pines growing in a subarctic area with low ambient pollution levels were irrigated with simulated acid rain during two summers. Neodiprion larvae fed with foliage from the experimental trees were infected with a dilute virus suspension.

The effects of acidic irrigation on soil microorganisms at Kevo, Northern Finland.

Effects of simulated acid rain (a mixture of H(2)SO(4) and HNO(3); pH(3)) on soil microbiology were studied in a field experiment in northern Finland. Irrigated control plots received the same amount of spring water (pH 6) as the acid treated plots. Fungal lengths and total bacterial numbers were studied after the treatments had continued for three growing seasons.

Delayed inducible resistance against a leaf-chewing insect in four deciduous tree species.

Both mechanical damage to mountain birch foliage and rearing of moth larvae on the trees reduced the growth of Epirrita autumnata larvae reared on these trees in the following year. The effects of physical damage and some other cues from insects were additive. On bird cherry the performance of Epirrita larvae was equal on untreated trees and on trees artificially defoliated in the previous year, but larval growth was reduced on previously insect-damaged branches.

The effect of simulated acid rain on performance of the aphid Euceraphis betulae (Koch) on silver birch.

The effect of artificial acid rain on the reproduction and survival of the aphid Euceraphis betulae on silver birch was studied in Turku, southern Finland. Eight bioassays were done during 1984-1986. In four of the bioassays the aphids produced 40% to over 100% more progeny on birches watered with dilute sulphuric acid (pH 3.

Long-term inducible resistance in birch foliage: triggering cues and efficacy on a defoliator.

Heavy damage of the mountain birch foliage, as well as application of small amounts of insect frass to the soil beneath the trees, reduced growth of Epirrita autumnata larvae reared in these trees in the following year. Foliage damage in the previous year decreased larval survival, too. Both foliage damage and insect frass in the soil decreased a fecundity index which combined the effects of size and survival.

Low nutritive quality as defence against herbivores: induced responses in birch.

The effects of artificial defoliation of birch trees in the previous year on the consumption and utilization of food by a geometrid larva, Epirrita autumnata, were studied in laboratory. The leaves were collected from two sites on a slope of a fell. Defoliation had a significant retarding effect on approximate digestibility, efficiency of conversion of ingested food, relative consumption rate and relative growth rate but not on efficiency of conversion of digested food.