Pigliucci, M. 2002: Are ecology and evolutionary biology "soft" sciences? — Ann. Zool. Fennici 39: 87–98.
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Ylikarjula, J., Heino, M., Dieckmann, U. & Kaitala, V. 2002: Does density-dependent individual growth simplify dynamics in age-structured populations? A general model applied to perch, Perca fluviatilis. — Ann. Zool. Fennici 39: 99–107.
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Lundkvist, E., Landin, J. & Karlsson, F. 2002: Dispersing diving beetles (Dytiscidae) in agricultural and urban landscapes in south-eastern Sweden. — Ann. Zool. Fennici 39: 109–123.
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Hromada, M., Tryjanowski, P. & Antczak, M. 2002: Presence of the great grey shrike Lanius excubitor affects breeding passerine assemblage. — Ann. Zool. Fennici 39: 125–130.
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Koivula, M. 2002: Boreal carabid-beetle (Coleoptera, Carabidae) assemblages in thinned uneven-aged and clear-cut spruce stands. — Ann. Zool. Fennici 39: 131–149.
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Kotta, J. & Møhlenberg, F. 2002: Grazing impact of Mytilus edulis L. and Dreissena polymorpha (Pallas) in the Gulf of Riga, Baltic Sea estimated from biodeposition rates of algal pigments. — Ann. Zool. Fennici 39: 151–160.
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Kaitala, V. 2002: Travelling waves in spatial population dynamics. — Ann. Zool. Fennici 39: 161–171.
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Saarinen, K. & Jantunen, J. 2002: A comparison of the butterfly fauna of agricultural habitats under different management history in Finnish and Russian Karelia. — Ann. Zool. Fennici 39: 173–181.
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Pigliucci, M. 2002: Are ecology and evolutionary biology "soft" sciences? — Ann. Zool. Fennici 39: 87–98. Ylikarjula, J., Heino, M., Dieckmann, U. & Kaitala, V. 2002: Does density-dependent individual growth simplify dynamics in age-structured populations? A general model applied to perch, Perca fluviatilis. — Ann. Zool. Fennici 39: 99–107. Lundkvist, E., Landin, J. & Karlsson, F. 2002: Dispersing diving beetles (Dytiscidae) in agricultural and urban landscapes in south-eastern Sweden. — Ann. Zool. Fennici 39: 109–123. Hromada, M., Tryjanowski, P. & Antczak, M. 2002: Presence of the great grey shrike Lanius excubitor affects breeding passerine assemblage. — Ann. Zool. Fennici 39: 125–130. Back to the top
Koivula, M. 2002: Boreal carabid-beetle (Coleoptera, Carabidae) assemblages in thinned uneven-aged and clear-cut spruce stands. — Ann. Zool. Fennici 39: 131–149. Kotta, J. & Møhlenberg, F. 2002: Grazing impact of Mytilus edulis L. and Dreissena polymorpha (Pallas) in the Gulf of Riga, Baltic Sea estimated from biodeposition rates of algal pigments. — Ann. Zool. Fennici 39: 151–160. Back to the top
Kaitala, V. 2002: Travelling waves in spatial population dynamics. — Ann. Zool. Fennici 39: 161–171. Saarinen, K. & Jantunen, J. 2002: A comparison of the butterfly fauna of agricultural habitats under different management history in Finnish and Russian Karelia. — Ann. Zool. Fennici 39: 173–181.
Research in ecology and evolutionary biology (evo-eco) often tries to emulate the "hard" sciences such as physics and chemistry, but to many of its practitioners feels more like the "soft" sciences of psychology and sociology. I argue that this schizophrenic attitude is the result of lack of appreciation of the full consequences of the peculiarity of the evo-eco sciences as lying in between a-historical disciplines such as physics and completely historical ones as like paleontology. Furthermore, evo-eco researchers have gotten stuck on mathematically appealing but philosophically simplistic concepts such as null hypotheses and p-values defined according to the frequentist approach in statistics, with the consequence of having been unable to fully embrace the complexity and subtlety of the problems with which ecologists and evolutionary biologists deal with. I review and discuss some literature in ecology, philosophy of science and psychology to show that a more critical methodological attitude can be liberating for the evo-eco scientist and can lead to a more fecund and enjoyable practice of ecology and evolutionary biology. With this aim, I briefly cover concepts such as the method of multiple hypotheses, Bayesian analysis, and strong inference.
Availability of resources is a limiting factor for many populations. Diminished resource availability due to intraspecific competition is expected to decrease the annual growth increments of individuals. We study an age-structured population model for individuals with indeterminate growth and annual reproduction; parameters of the model are chosen to characterize a population with life history similar to the Eurasian perch. Different variants of this model are analyzed, all of which have a potential for exhibiting non-equilibrium population fluctuations. We demonstrate that incorporating density-dependent individual growth into these models changes the dynamics of these populations by damping or even eradicating fluctuations in abundance and biomass. This finding offers an explanation for the observed stable dynamics of unperturbed perch populations. Further, density-dependent individual growth may also be a significant factor contributing to the conspicuous empirical rarity of non-equilibrium population dynamics in general.
Flying dytiscids were trapped in an agricultural landscape with wetlands in different successional stages and in two urban landscapes with young wetlands. We compared the faunas in air and in water. Hydroporus and Agabus were the most frequently trapped genera in air. Most species were trapped near water in the agricultural landscape; species characteristic of later successional stages were common in air and dominated in water. In the urban landscapes, species were mainly trapped far from water and species known to colonise new waters were common in air and in the youngest waters. Overall, females and immature adults were more common in flight catches during April–July than during August–October. Our results indicate that urbanisation would result in a less diverse fauna, but may lead to an assemblage dominated by species that are infrequent in agricultural landscapes. To obtain a rich wetland insect fauna, a wide range of wetland types is required at the landscape scale.
The great grey shrike, Lanius excubitor, is known to be a raptor-like passerine. In addition to invertebrate prey, its diet also consists of vertebrates, including small birds. We examined the effect of presence of the great grey shrike on the breeding assemblages of small passerine birds in an intensively farmed landscape in western Poland. Line transects were used for bird censuses. Birds were counted at 29 treatment transects (length 500 m, width 100 m), located within shrike territory, as well as 29 control transects, situated > 800 m from the nearest shrike nest. Treatment and control transects did not differ with respect to the habitat composition. We did not detect any difference between territories and controls regarding either numbers of recorded bird species, or pairs. However, the vicinity of shrike nests negatively affected the total density of the skylark Alauda arvensis, the most abundant bird species and important item of shrike bird prey, and the whinchat Saxicola rubetra. The results indicate that the presence of the great grey shrike selectively affects species of breeding bird communities.
Forestry has altered the boreal flora and fauna strongly during the 1900s. At present, logging methods other than clear-cutting are often applied but the ecological effects of these modifications are poorly studied. I collected carabid beetles in 8 uncut, 8 thinned (10%–30% of trees removed, with the aim of generating an uneven age structure) and 8 clear-cut, spruce-dominated stands, by using pitfall traps in central Finland during 1995–1998. The carabid species fell into three distinctive ecological groups in the multivariate analyses: forest, open-habitat and Sphagnum bog species. The forest species further formed a continuum from forest specialists to canopy-closure generalists. Logging affected the forest species slightly, while generalists and open-habitat species benefitted from clear-cutting. Thinning maintained the forest-floor carabid assemblage well. Site characteristics, such as the amount of trees and bottom and field-layer vegetation, were important determinants of carabid assemblages. Certain within-stand habitat types (e.g. spruce mires) were shown to be important for carabid diversity and should be managed with methods other than clear-cutting, in order to avoid extinctions of local populations. Increasing distance to the nearest source habitat had a negative effect on the abundance and distribution of carabids. Therefore, landscape-level forestry planning is also important for the maintenance of forest-species assemblages.
Grazing rates of Mytilus edulis and Dreissena polymorpha were estimated in the Gulf of Riga in May and July 1996. The faecal material was quantified using chlorophyll a (Chl a) as tracer for planktonic algae. Faeces production rate of M. edulis (shell length: 20 mm) ranged from 0.02 to 0.40 µg Chl a equivalent ind.–1 h–1 and that of D. polymorpha from 0.01 to 0.85 µg Chl a equivalent ind.–1 h–1, respectively. Filtration rates of the mussels were lower at lower temperatures in May. The defaecation rate increased curvlinearly with ambient concentration of Chl a and levelled off at high food concentration. After correcting for loss of fluorescent material during gut passage the population grazing impact of M. edulis was estimated at 8% d–1 of the Chl a stock in the littoral zone in May and 67% d–1 in July. The values for D. polymorpha were 5% d–1 and 29% d–1, respectively. A high grazing impact by M. edulis in the coastal zone during summer was supported by strong horizontal and vertical gradients in Chl a. Hence, the populations of benthic suspension feeders in the littoral zone of the Gulf of Riga constitute an important sink for primary production, especially in summer.
The modern theoretical ecology has identified travelling waves as one of the appealing features suggesting that spatially structured populations may be self-organized. Using a set of population renewal models in one-dimensional space, generating regular periodic fluctuations, we seek possibilities to identify travelling waves superimposed on the local dynamics. The waves move at a known speed to one direction. The speed of the waves and the local population dynamics may be modulated by noise. Our study suggests that the indicators of travelling waves are, first, the overall level of synchrony among the populations is low, second, the frequency distribution of the synchrony measure is bimodal (i.e., it has low central tendency); and third, there is either no or a weakly decreasing trend between the level of synchrony and distance between the populations compared. These features are most easily recovered by cyclic or quasi-periodic dynamics. Data has recently started to accumulate to indicate that the theory-anticipated travelling waves are also found in dynamics of natural populations.
Butterfly communities were studied along field boundaries in agricultural habitats in Finnish and Russian Karelia. A total of 34 sites represented typical arable land in both countries, i.e. modern cereal and forage cultivation in Finland (n = 17) and old fashioned hay cultivation in Russia (n = 17). Transect count data obtained over three years (1997–1999) consisted of 55 species and 11759 individuals: 53 species and 5382 individuals in Finland, and 49 species and 6377 individuals in Russia. Despite various differences in the long-term exploitation of arable land, the species composition and the total abundance of butterflies were rather similar in both countries, but the species richness and diversity were higher in Finland. The different structure of agricultural landscapes and differences between the two countries as regards the distribution of field vegetation and cultivation practices in the studied habitats were regarded as the main factors responsible for the result being contradictory to the authors' expectations.