Hanski, I. 2002: In the midst of ecology, conservation, and competing interests in the society. — Ann. Zool. Fennici 39: 183–186.

This essay is about the role of ecologists in policy-determining and decision-making processes in the society in which research results may play, and are expected to play, a constructive role. The incentive for writing this essay came from my involvement, over the past several years, in the research and conservation-planning of boreal forest biodiversity in Finland. Forest biodiversity is a much debated issue in Finland, where forest industry represents an important sector of the economy and has become so advanced technologically and in terms of the infrastructure that the ever-diminishing work force can manage the entire area of 20 million ha of forests — practically down to single big trees. Biodiversity has become a fundamental concern in boreal forestry, because this is an industry that is based on the use of just a few species, but in a manner that will influence thousands of non-target species living in the same area. Arguably, current boreal forestry as practiced in e.g. Finland is sustainable from the perspective of the dynamics of the target tree species, but not from the perspective of the forest communities as a whole.

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Ukkonen, P. 2002: The early history of seals in the northern Baltic. — Ann. Zool. Fennici 39: 187–207.

All available data, both from geological stray finds and archaeological refuse faunas, of the early occurrence of seals in the northern Baltic were summarized. Ten subfossil seals found in different parts of the Finnish coast were radiocarbon dated. The ringed seal (Phoca hispida), a resident species in the area, colonized the Baltic at 9500 BP, at the latest. The harp seal (Phoca groenlandica), which currently does not inhabit the Baltic, was part of the northern Baltic fauna from 5900 BP to 2800 BP, at least. Based on both geological and archaeological bone finds the harp seal was during this time common even in the northernmost parts of the Gulf of Bothnia, whereas the grey seal (Halichoerus grypus), today a common species in the area, seems to have been extremely rare in the whole northern Baltic. Identification of seals to species level is — to some extent — possible even from burnt and highly fragmented bone material found at prehistoric dwelling sites in Finland.

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Vences, M., Galán, P., Vieites, D. R., Puente, M., Oetter, K. & Wanke, S. 2002: Field body temperatures and heating rates in a montane frog population: the importance of black dorsal pattern for thermoregulation. — Ann. Zool. Fennici 39: 209–220.

Thermoregulation is particularly important for amphibians under heterothermic high-altitude conditions, but remains largely unstudied in montane frogs. Field body temperatures (7.2–26.5 °C) in a Pyrenean population of the common frog (Rana temporaria) at 2100 m altitude were significantly higher than environmental temperatures (air, substrate, water) during the day. At night, the highest body temperatures were observed in individuals in the pond, which acted as a temperature buffer during the nocturnal drop in air temperature. Our results indicate active thermoregulation in these frogs, which was also verified by the observational data on basking individuals. No influence of the amount of black dorsal pattern on body temperatures was found in the field data, but body temperatures of individuals exposed experimentally to the sun were higher in dark than in lighter individuals. These trends were similar to those found in melanic snakes, and support the hypothesis that the black pattern in montane Rana temporaria may provide benefits in terms of time allocation by enabling frogs to attain their preferred body temperatures more quickly.

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Kallio-Nyberg, I., Saura, A. & Ahlfors, P. 2002: Sea migration pattern of two sea trout (Salmo trutta) stocks released into the Gulf of Finland. — Ann. Zool. Fennici 39: 221–235.

The sea migration of two sea trout stocks was examined in a tagging and transplantation experiment. The two different stocks, which originated from the rivers Isojoki (Gulf of Bothnia) and Ingarskilanjoki (Gulf of Finland), were released in 1994–1996 as smolts (3991 and 3996 smolts) at two nearby sites in the Gulf of Finland. The tag recovery data received 5–19 months after release (Sep.–Nov.) from the Gulf of Finland were analysed. The recovery rate was about 8%. Multi-way contingency analysis showed that the origin of the stock affected the spatial and temporal sea distribution. The majority (63%) of the Ingarskilanjoki sea trout, but a smaller proportion (49%) of the Isojoki sea trout, were caught in coastal waters, near the release site. The stock-specific spatial sea distributions were not affected by the gear types used. The genetic threats of stocking are discussed.

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Vamosi, S. M. 2002: Predation sharpens the adaptive peaks: survival trade-offs in sympatric sticklebacks. — Ann. Zool. Fennici 39: 237–248.

This study tests whether living in different lake habitats in benthic and limnetic sticklebacks (Gasterosteus aculeatus complex) has resulted in divergence of antipredator traits and habitat-associated survival trade-offs. Adult benthics were larger than limnetics, had poorly developed defensive armour and showed no tendency to school with conspecifics. Limnetics, in contrast, were smaller, had well developed defensive armour and demonstrated strong schooling behaviour. In littoral arenas, juvenile limnetics were significantly more vulnerable than juvenile benthics to predation by adult benthics and backswimmers (Notonecta sp.) but not dragonfly larvae (Aeshna sp.). This pattern was reversed in open water arenas when adult benthics and limnetics were exposed to diving avian predators, double-crested cormorants (Phalacrocorax auritus). These findings show that divergence in antipredator traits between benthic and limnetic sticklebacks has accompanied divergence in foraging traits, resulting in survival trade-offs in addition to those previously observed for foraging success and growth rates across habitats.

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Laakkonen, J. 2002: Relative medullary thickness of shrews from arid environments: Intraspecific spatial analysis, and comparison to arctic shrews and tropical tenrecs. — Ann. Zool. Fennici 39: 249–255.

Spatial analysis on the relative medullary thickness (RMT) of sympatric shrews Notiosorex crawfordi and Sorex ornatus from different habitats in southern California showed no significant intraspecific differences between habitats but RMTs of N. crawfordi were significantly higher than those of S. ornatus. Interspecific comparison of RMTs of Sorex shrews from Alaska did not differ significantly from each other but they were significantly lower than those of both shrew species from southern California. RMTs of another group of insectivorous mammals, the Microgale shrew tenrecs from Madagascar, did not differ significantly between species, or from those of shrews from mesic habitats. The interspecific comparisons showed that RMT is an informative way to estimate the ability of an insectivorous species to occur in arid habitats, and to compare the RMTs of closely related sympatric mammals.

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Hellstedt, P., Kalske, T. & Hanski, I. 2002: Indirect effects of least weasel presence on field vole behaviour and demography: a field experiment. — Ann. Zool. Fennici 39: 257–265.

Predation by small mustelids is widely considered to be the most likely mechanism to maintain multiannual fluctuations of vole populations in Fennoscandia. Apart from the direct effect of predation, small mustelids have been suggested to have indirect effects on vole population dynamics. We studied in a field experiment the indirect effects of the presence of the least weasel (Mustela nivalis nivalis) on behaviour and demography of field voles (Microtus agrestis). We constructed grids made of drainpipe with small holes and covering an area of 0.24 ha (4
* 6-m grid, pipes with 10-m intervals). A least weasel moved in the experimental grid without having access to voles during the entire experiment, lasting for 11 weeks. We analysed the rate of maturation, breeding success, movements, and home range use of field voles in the experimental and control grids. The results indicate that weasel's presence had no or had only minor effects on voles.

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Hasegawa, E., Tinaut, A. & Ruano, F. 2002: Molecular phylogeny of two slave-making ants: Rossomyrmex and Polyergus (Hymenoptera: Formicidae). — Ann. Zool. Fennici 39: 267–271.

Using mitochondrial cytochrome oxidase I gene (COI), we established the phylogenetic relationship between two slave-making genera of the tribe Formicini: Polyergus and Rossomyrmex. The resulting phylogenetic tree presents two well-defined groups: Formica + Polyergus, and Proformica + Cataglyphis + Rossomyrmex. Our result contradicts prior classifications which considered Polyergus and Rossomyrmex to be sister genera. These results imply that slave-making in the two taxa evolved independently.

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