Vepsäläinen, K., Savolainen, R., Tiainen, J. & Vilén, J. 2000: Successional changes of ant assemblages: from virgin and ditched bogs to forests. — Ann. Zool. Fennici 37: 135–149.
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Kauhala, K., & Helle, P. 2000: The interactions of predator and hare populations in Finland — a study based on wildlife monitoring counts. — Ann. Zool. Fennici 37: 151–160.
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Jedrzejewski, W., Jedrzejewska, B., Zub, K. & Nowakowski, W. K. 2000: Activity patterns of radio-tracked weasels Mustela nivalis in Bialowieza National Park (E Poland). — Ann. Zool. Fennici 37: 161–168.
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Bolbroe, T., Jeppesen, L. L. & Leirs, H. 2000: Behavioural response of field voles under mustelid predation risk in the laboratory: more than neophobia. — Ann. Zool. Fennici 37: 169–178.
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Alonso, C., Vuorisalo, T., Wilsey, B. & Honkanen, T. 2000: Yponomeuta evonymellus outbreaks in southern Finland: spatial synchrony but different local magnitudes. — Ann. Zool. Fennici 37: 179–188.
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Väyrynen, T., Siddall, R., Valtonen, E. T. & Taskinen, J. 2000: Patterns of trematode parasitism in lymnaeid snails from northern and central Finland. — Ann. Zool. Fennici 37: 189–199.
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Abildsnes, J. & Tømmerås, B. Å. 2000: Impacts of experimental habitat fragmentation on ground beetles (Coleoptera, Carabidae) in a boreal spruce forest. — Ann. Zool. Fennici 37: 201–212.
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Vepsäläinen, K., Savolainen, R., Tiainen, J. & Vilén, J. 2000: Successional changes of ant assemblages: from virgin and ditched bogs to forests. — Ann. Zool. Fennici 37: 135–149.
We studied ant assembly changes after ditching of bogs with nest and pitfall sampling in the southern Finnish taiga. The study sites clustered in dendrograms to hierarchical sets: virgin bogs and young ditchings, older ditchings, and forests. Species richness was low on virgin bogs and young ditchings, and increased with the age of ditching. The number of species was highest in clearcut, and decreased in spruce forests with increasing density of wood ants. Three bog specialists, Formica uralensis, F. picea and Myrmica scabrinodis, were found only on bogs. Nation-wide draining of bogs implies severe decreases in their population densities. As a corollary, the poorly known but potentially healthy populations of the obligate social parasite of M. scabrinodis, Myrmica karavajevi, may go extinct in extensive regions, because of its need of high nest densities of the host species. The effects of habitat attributes on the local number of species were overshadowed by top-dominant, polydomous wood ants. A wood with practically no F. aquilonia harboured 11 other ant species, whereas in high-density wood-ant forest only two other species were located. Pre-emption by the slave-maker F. sanguinea may in several ways slow down the spread of wood ants to ditched bogs.
Kauhala, K., & Helle, P. 2000: The interactions of predator and hare populations in Finland — a study based on wildlife monitoring counts. — Ann. Zool. Fennici 37: 151–160.
Numerical relationships between predators (red fox Vulpes vulpes, pine marten Martes martes, lynx Lynx lynx) and mountain hare (Lepus timidus) were studied using the data from the Finnish wildlife monitoring scheme in 1989–2000. Line transect (wildlife triangle) data were used to obtain snow track indices of relative predator abundance. Finland was divided into 29 100 x 100 km squares, each including the mean of 348 km of transect line (total length > 10000 km annually). The abundance of fox was related to the yearly growth rate of hare populations in 48% of the squares. The growth rates of fox and hare populations also correlated in 45% of the squares, indicating that there was a mutual relationship between hare and fox populations in about half of the squares. This relationship existed in areas with low/moderate hare and high fox numbers (a low hare/fox index) but was lacking in areas with a high hare/fox index, pointing to both functional and numerical response for foxes preying on hares. There was also a positive spatial correlation between hare and lynx numbers, but the correlation between hare and marten numbers was weak.
Jedrzejewski, W., Jedrzejewska, B., Zub, K. & Nowakowski, W. K. 2000: Activity patterns of radio-tracked weasels Mustela nivalis in Bialowieza National Park (E Poland). — Ann. Zool. Fennici 37: 161–168.
Diel activity rhythms and factors affecting the duration of daily activity were studied in nine male common weasels Mustela nivalis vulgaris, radio-tracked in the pristine deciduous woodland in eastern Poland from April 1990 to August 1991. During the study, mean daily temperature varied from –5.3 °.C to 25.5 °.C, and densities of forest rodents (bank voles Clethrionomys glareolus and yellow-necked mice Apodemus flavicollis) ranged from 2 to 270 ind. ha–1. Weasels showed clearly diurnal activity, with a peak around 1000–1300 hrs. On average, weasels were active for 3.8 h day–1 (SE = 0.3, range 0–14 h day–1), with 0 to 7 bouts of activity (mean 2.1, SE = 0.1), each bout lasting, on average, 1.8 h (SE = 0.1). Spells of activity were separated by short inactivity bouts (on average 2 h, SE = 0.2). Long (nocturnal) inactivity lasted, on average 17.5 h day–1 (SE = 0.7). A remarkable seasonal variation in the duration of weasel daily activity and number of activity bouts per day was related to changes in ambient temperature. In winter, weasels were active in 1–2 bouts day–1 each bout lasting 1–2 h; whereas in summer they showed 3–4 (maximally 7) bouts of activity. The highest level of activity coincided with the mating season. Fluctuations of rodent numbers had little effect on weasel activity pattern.
Bolbroe, T., Jeppesen, L. L. & Leirs, H. 2000: Behavioural response of field voles under mustelid predation risk in the laboratory: more than neophobia. — Ann. Zool. Fennici 37: 169–178.
In the present study, we focus on the time budgets around feeding behaviour, by observing the behaviour of 24 field voles Microtus agrestis (Linnaeus, 1761) in the laboratory, exposed to no odour, faeces from a least weasel Mustela nivalis Linnaeus, 1766 and a domestic rabbit Oryctolagus cuniculus (Linnaeus, 1758). The voles did show a comprehensive response when exposed to weasel odour, while exposure to rabbit odour caused only a single minor effect. The difference in response to the two odours rules out neophobia as the underlying cause of the behavioural changes. Voles exposed to weasel odour were more inactive, ate less of a high preference food that was placed far from the nest-box, displayed a smaller variation of behaviour types and their activities were overall more interrupted. Our study confirmed that the mere risk of predation affects voles' feeding behaviour. This may explain indirect effects of predation risk on other processes like reproduction.
Alonso, C., Vuorisalo, T., Wilsey, B. & Honkanen, T. 2000: Yponomeuta evonymellus outbreaks in southern Finland: spatial synchrony but different local magnitudes. — Ann. Zool. Fennici 37: 179–188.
Defoliations of Prunus padus by Yponomeuta evonymellus were monitored in two areas in southern Finland. During a long-term study (1980–1995) in the area with high peak defoliations, P. padus trees recorded two defoliation peaks, leading to complete defoliation of many trees. The negative relationship between pupal mass and current year tree defoliation during the peak years suggested shortage of food affected reproductive potential of Y. evonymellus. Furthermore, no delayed induced resistance was observed in these populations. Interannual correlations in °rees of defoliation experienced by individual trees were low, i.e. high defoliation in one year did not predict the °ree of defoliation the following year. We also detected a sharp increase in parasitism rates with defoliation between years. In the other study area located about 150 km NW, only 4% of more than 200 study trees experienced defoliations higher than 50%. In this population, high defoliation of tree individuals in one year predicted low defoliation in the following year. In addition, rates of parasitism were less variable and intermediate compared to those in the high peak area. Altogether, the relatively rapidly operating negative feedback in the low peak — compared with the high peak area — was consistent with the difference between both areas in the levels of peak densities.
Väyrynen, T., Siddall, R., Valtonen, E. T. & Taskinen, J. 2000: Patterns of trematode parasitism in lymnaeid snails from northern and central Finland. — Ann. Zool. Fennici 37: 189–199.
A species rich and prevalent larval digenean fauna was found in lymnaeid snail populations from two lakes in northern Finland (Kuivasjärvi and Pyykösjärvi populated by L. stagnalis and L. peregra, respectively) and ten years later in a third lake in central Finland (Kuuhankavesi populated by L. stagnalis). Echinostomes were common to all lakes, one species overlapping between Pyykösjärvi and Kuuhankavesi (Echinostoma revolutum). All three lymnaeid populations also harboured xiphidiocercariae of Plagiorchis elegans, furcocercariae of Diplostomum pseudospathaceum and Trichobilharzia ocellata and the monostome Notocotylus attenuatus. A consistent seasonal pattern of infection was recorded for four of the parasites in Pyykösjärvi, although annual variation in mean prevalence was generally significant. Annual parasite species composition within the three lakes was relatively stable despite the long dormant winter. This may be due to the over-wintering of larval digeneans in infected snails that then act as a source of reinfection of bird definitive hosts each spring.
Abildsnes, J. & Tømmerås, B. Å. 2000: Impacts of experimental habitat fragmentation on ground beetles (Coleoptera, Carabidae) in a boreal spruce forest. — Ann. Zool. Fennici 37: 201–212.
A fine-scale fragmented area (twenty-two 40 x 40 m clear-cuts) and a coarse-scale fragmented area (three 150 x 150 m clear-cuts) were created in a spruce forest in Norway during 1995–1996. Before and after the logging, in 1994 and 1997 respectively, ground beetles were sampled in pitfall traps between the clear-cuts and from an untouched control area. Seven eurytopic forest species accounted for 99% of the catch. In the fine-scale fragmented area the abundance of Leistus terminatus was significantly negatively affected by fragmentation, whereas in the coarse-scale fragmented area L. terminatus, Trechus obtusus and Calathus micropterus were significantly negatively affected. No clear indications of area or edge effects were found. Isolation effects probably were minimal. The ambiguity in the explanation of the results is likely to be due to species-specific and complex responses to the different aspects of habitat fragmentation.