On the Notion of Microrange of Soil Testaceans

We studied species composition and population structure of testaceans (Protozoa: Testacea) in a series of soil microblock samples (weighing between 5 and 0.05 g) from podzol horizons L, F, A1A2, and A2 of cowberry-heath-lichen and gramineous-cowberry pine forests. Similarity between the testacean communities in the soil microblock samples from horizon A1A2 was at least 0.94 (by Morisita-Horn index of similarity, quantitative data), while in the enzymatic layer of litter it decreased to 0.34. The notion of microrange of soil-forming testaceans is proposed and discussed on the basis of the obtained and published data.     

The nature of spatial transitions in the Arctic

Aim Describe the spatial and temporal properties of transitions in the Arctic and develop a conceptual understanding of the nature of these spatial transitions in the face of directional environmental change. Location Arctic tundra ecosystems of the North Slope of Alaska and the tundra‐forest region of the Seward Peninsula, Alaska Methods We synthesize information from numerous studies on tundra and treeline ecosystems in an effort to document the spatial changes that occur across four arctic transitions. These transitions are: (i) the transition between High‐Arctic and Low‐Arctic systems, (ii) the transition between moist non‐acidic tundra (MNT) and moist acidic tundra (MAT, also referred to as tussock tundra), (iii) the transition between tussock tundra and shrub tundra, (iv) the transition between tundra and forested systems. By documenting the nature of these spatial transitions, in terms of their environmental controls and vegetation patterns, we develop a conceptual model of temporal dynamics of arctic ecotones in response to environmental change. Results Our observations suggest that each transition is sensitive to a unique combination of controlling factors. The transition between High and Low Arctic is sensitive primarily to climate, whereas the MNT/MAT transition is also controlled by soil parent material, permafrost and hydrology. The tussock/shrub tundra transition appears to be responsive to several factors, including climate, topography and hydrology. Finally, the tundra/forest boundary responds primarily to climate and to climatically associated changes in permafrost. There were also important differences in the demography and distribution of the dominant plant species across the four vegetation transitions. The shrubs that characterize the tussock/shrub transition can achieve dominance potentially within a decade, whereas spruce trees often require several decades to centuries to achieve dominance within tundra, and Sphagnum moss colonization of non‐acidic sites at the MNT/MAT boundary may require centuries to millennia of soil development. Main conclusions We suggest that vegetation will respond most rapidly to climatic change when (i) the vegetation transition correlates more strongly with climate than with other environmental variables, (ii) dominant species exhibit gradual changes in abundance across spatial transitions, and/or (iii) the dominant species have demographic properties that allow rapid increases in abundance following climatic shifts. All three of these properties characterize the transition between tussock tundra and low shrub tundra. It is therefore not surprising that of the four transitions studied this is the one that appears to be responding most rapidly to climatic warming.     

Factors determining plant species richness in Alaskan arctic tundra

Abstract. We studied the relationship between plant N:P ratio, soil characteristics and species richness in wet sedge and tussock tundra in northern Alaska at seven sites. We also collected data on soil characteristics, above‐ground biomass, species richness and composition. The N:P ratio of the vegetation did not show any relationship with species richness. The N:P ratio of the soil was related with species richness for both vegetation types. Species richness in the tussock tundra was most strongly correlated with soil calcium content and soil pH, with a strong correlation between these two factors. N:P ratio of the soil was also correlated with soil pH. Other factors correlated with species richness were soil moisture and Sphagnum cover. Organic matter content was the factor most strongly correlated with species richness in the wet sedge vegetation. N:P ratio of the soil was strongly correlated with organic matter content. We conclude that N:P ratio in the vegetation is not an important factor determining species richness in arctic tundra and that species richness in arctic tundra is mainly determined by pH and flooding. In tussock tundra the pH, declining with soil age, in combination with Sphagnum growth strongly decreases species richness, while in wet sedge communities flooding over long periods of time creates less favourable conditions for species richness.     

Ecology of heath communities dominated by Cassiope tetragona at Alexandra Fiord, Ellesmere Island, Canada

At a high arctic lowland on Ellesmere Island, heath communities dominated by Cassiope tetragona were widespread, and occurred in a variety of habitats that differred in time of snowmelt, relative site moisture, soil thaw depth, and air and soil temperature. Cover, standing crop, and production were dominated by woody plants, notably Cassiope tetragona and Dryas integrifolia . The Cassiope -dominated heaths were similar in composition to those at other Canadian high arctic localities, but were less similar to localities in Greenland and Spitzbergen. Compositional relationships among Cassiope -dominated heaths in different habitats at the study site may be largely determined by two interrelated environmental factors, time of snowmelt and site moisture.
Aboveground vascular plant biomass was concentrated near the ground surface, resulting in simple vertical structure that takes advantage of relatively warm soil and air temperatures in summer, and a protective snow cover in winter. Aboveground vascular plant standing crop was largely comprised of attached dead tissue, and there were equal proportions of above- and belowground biomass. Low community production was due to dominance by long-lived, slow-growing species, and to short growing seasons and cold temperatures. Overall character of Cassiope -dominated heaths reflects the conservative, stress tolerant growth strategy of the dominant species, Cassiope tetragona .     

Ecology of the active soil microfauna (Protozoa, Metazoa) of Wilkes Land, East Antarctica

Active ciliates, testate amoebae, nematodes, rotifers and tardigrades were examined in fresh and preserved fellfield, moss and ornithogenic soil samples of Wilkes Land. Direct counting was used to investigate abundances, community structures and protozoan diversity. Twenty-six ciliate species (nine first records for continental Antarctica, one undescribed) and five testacean species (three new records) were found. Two Colpoda species were active, further disproving Smith's hypothesis that this genus is absent in continental Antarctica. Animal frequencies varied between habitats but every group occurred in at least 74% of the samples, rotifers (95%) and testaceans (92%) being most frequent. Highest abundances were recorded in moss: 354 ciliates/g dry soil (19 species), 671 testaceans (5 species), 513 nematodes, 1,311 rotifers and 4,607 tardigrades, which thus dominated. Rotifers were most abundant in the other habitats. The microfauna was not randomly distributed because individual numbers were often strongly intercorrelated. Water and organic matter content were relevant environmental parameters; air temperature and pH probably had indirect effects. Received:28 August 1996 / Accepted:23 November 1996     

Abiontic enzymes in arctic soils: changes in sulphatase activity following vehicle disturbance

Summary The effect of vehicle perturbation on sulphatase enzyme activity in arctic tundra soils was examined. Sulphatase activity was significantly less in disturbed (vehicle track) than that adjacent undisturbed tundra soils. Soil moisture and water movement appeared to be major controlling factors. The results of the study suggest that biochemical mineralization of organic sulphur in disturbed tundra soils is controlled by nutrient influx associated with water movement, altering sulphatase activity to a level consistent with the need for, as well as the supply of, the mineralized element.     

Ecological aspects of development of testacean complexes in nests of Formica lugubris and Formica exsecta (Hymenoptera, Formicidae)

Testacean population in the nests of Formica lugubris and F. exsecta was studied in a spruce forest and in a mixed birch forest. Samples of the nest material (spruce litter and grass fragments) were taken from the surface layers, the inner parts of the nests, and from underlying soil. In all, 33 species of testaceans were identified. The highest species diversity and abundance were observed in the Formica lugubris nests, in the upper layer of the F. exsecta nest, and in the spruce litter. In all the samples, 10 widespread aerophilic and edaphic species (Centropyxis aerophila, C. sylvatica, C. orbicularis, Cyclopyxis kahli, Trinema lineare, and others) were the most common, resulting in a uniform species composition in all the habitats studied. In the presence of the relevant substrate, this group is supplemented by species of appropriate ecological groups (bryophilic, acidophilic, and inhabitants of coarse humus). In the inner part of the Formica lugubris nest, the testacean population is characterized by a very high abundance of Plagiopyxis penardi, whereas the surface layer of the F. exsecta nest is characterized by abundant Cyclopyxis eurystoma and very low species diversity in the inner layers. The initial composition and decree of decomposition of plant remains due to ant activity are considered as the main factors responsible for the testacean species diversity, as well as the availability of substrates suitable for the development of different ecological groups of testaceans.     

Butterflies (Lepidoptera, Rhopalocera) in the Arctic fauna

The Arctic fauna includes 106 species of diurnal butterflies: Papilionidae (6 species), Pieridae (20), Lycaenidae (18), Nymphalidae (30), Satyridae (27), and Hesperiidae (5). Among them, representatives of the family Nymphalidae predominate as to the features characterizing the biological progress in the Arctic, as well as to the number of the most strongly pronounced arctic forms. The family Satyridae shares the first place with Nymphalidae by the number of species, but differs from the latter in the uneven or local distribution. The family Pieridae demonstrates a wide distribution of polyzonal and boreal species in the tundra zone. The distribution patterns of Lycaenidae are different in the Eurasian and Beringian-American sectors. Species of Papilionidae and Hesperiidae occur only in the southern part of the tundra zone. Each family is characterized by specific distribution in the Arctic subzones and landscapes and by latitudinal trends in its specific ratio in the faunas. There are 30 to 40 arctic species, including arctic proper (euarctic and hemiarctic) and hypoarctic, arctoalpine, arctomontane, and arctoboreal species. The species developing successfully under high-latitude conditions are Boloria chariclea, B. polaris, B. improba, Colias nastes, C. hecla, and Erebia fasciata; the first two species can be considered true euarctic forms. Specific features of the latitudinal and longitudinal distribution of the butterfly species in different parts of the Arctic are discussed.     

Open tundra persist,but arctic features decline—Vegetation changes in the warming Fennoscandian tundra

In the forest‐tundra ecotone of the North Fennoscandian inland, summer and winter temperatures have increased by two to three centigrades since 1965, which is expected to result in major vegetation changes. To document the expected expansion of woodlands and scrublands and its impact on the arctic vegetation, we repeated a vegetation transect study conducted in 1976 in the Darju, spanning from woodland to a summit, 200 m above the tree line. Contrary to our expectations, tree line movement was not detected, and there was no increase in willows or shrubby mountain birches, either. Nevertheless, the stability of tundra was apparent. Small‐sized, poorly competing arctic species had declined, lichen cover had decreased, and vascular plants, especially evergreen ericoid dwarf shrubs, had gained ground. The novel climate seems to favour competitive clonal species and species thriving in closed vegetation, creating a community hostile for seedling establishment, but equally hostile for many arctic species, too. Preventing trees and shrubs from invading the tundra is thus not sufficient for conserving arctic biota in the changing climate. The only dependable cure is to stop the global warming.     

Changes in the structure and function of northern Alaskan ecosystems when considering variable leaf‐out times across groupings of species in a dynamic vegetation model

The phenology of arctic ecosystems is driven primarily by abiotic forces, with temperature acting as the main determinant of growing season onset and leaf budburst in the spring. However, while the plant species in arctic ecosystems require differing amounts of accumulated heat for leaf‐out, dynamic vegetation models simulated over regional to global scales typically assume some average leaf‐out for all of the species within an ecosystem. Here, we make use of air temperature records and observations of spring leaf phenology collected across dominant groupings of species (dwarf birch shrubs, willow shrubs, other deciduous shrubs, grasses, sedges, and forbs) in arctic and boreal ecosystems in Alaska. We then parameterize a dynamic vegetation model based on these data for four types of tundra ecosystems (heath tundra, shrub tundra, wet sedge tundra, and tussock tundra), as well as ecotonal boreal white spruce forest, and perform model simulations for the years 1970–2100. Over the course of the model simulations, we found changes in ecosystem composition under this new phenology algorithm compared with simulations with the previous phenology algorithm. These changes were the result of the differential timing of leaf‐out, as well as the ability for the groupings of species to compete for nitrogen and light availability. Regionally, there were differences in the trends of the carbon pools and fluxes between the new phenology algorithm and the previous phenology algorithm, although these differences depended on the future climate scenario. These findings indicate the importance of leaf phenology data collection by species and across the various ecosystem types within the highly heterogeneous Arctic landscape, and that dynamic vegetation models should consider variation in leaf‐out by groupings of species within these ecosystems to make more accurate projections of future plant distributions and carbon cycling in Arctic regions.     

Testaceans (Testacea, Protozoa) of Taiga Soils in Western Siberia (Surgut Polesye)

We studied population structure of testaceans of automorphic and hydromorphic soils in the middle taiga of Western Siberia. Rich testacean fauna has been revealed. The fauna representation was comparable to the studied soils of Ciscaucasian Russia. The bryophilic group was the most typical for the region, since its representatives inhabited the predominating hydromorphic soils of bogs. The typical species included Amphitrema flavum, Heleopera petricola, Placocista spinosa, Trigonopyxis arcula, Centropyxis laevigata, Nebela tincta, Arcella catinus, as well as other moss forms. Flood plain proved to be the richest by testacean species variability among the studied habitats. The set of species here included both representatives of watershed and typical aquatic forms present due to the flood conditions of a given area. The highest quantitative indices of the testacean complexes were revealed in the forest area soils. Quadrulella quadrigera Deflandre, 1936 found in a flood plain area has been revealed for the first time in Russia.     

Reproduction as a bottleneck to treeline advance across the circumarctic forest tundra ecotone

The fundamental niche of many species is shifting with climate change, especially in sub‐arctic ecosystems with pronounced recent warming. Ongoing warming in sub‐arctic regions should lessen environmental constraints on tree growth and reproduction, leading to increased success of trees colonising tundra. Nevertheless, variable responses of treeline ecotones have been documented in association with warming temperatures. One explanation for time lags between increasingly favourable environmental conditions and treeline ecotone movement is reproductive limitations caused by low seed availability. Our objective was to assess the reproductive constraints of the dominant tree species at the treeline ecotone in the circumpolar north. We sampled reproductive structures of trees (cones and catkins) and stand attributes across circumarctic treeline ecotones. We used generalized linear mixed models to estimate the sensitivity of seed production and the availability of viable seed to regional climate, stand structure, and species‐specific characteristics. Both seed production and viability of available seed were strongly driven by specific, sequential seasonal climatic conditions, but in different ways. Seed production was greatest when growing seasons with more growing degree days coincided with years with high precipitation. Two consecutive years with more growing degree days and low precipitation resulted in low seed production. Seasonal climate effects on the viability of available seed depended on the physical characteristics of the reproductive structures. Large‐coned and ‐seeded species take more time to develop mature embryos and were therefore more sensitive to increases in growing degree days in the year of flowering and embryo development. Our findings suggest that both moisture stress and abbreviated growing seasons can have a notable negative influence on the production and viability of available seed at treeline. Our synthesis revealed that constraints on predispersal reproduction within the treeline ecotone might create a considerable time lag for range expansion of tree populations into tundra ecosystems.     

Red fox takeover of arctic fox breeding den: an observation from Yamal Peninsula, Russia

Here, we report from the first direct observation of a red fox (Vulpes vulpes) intrusion on an arctic fox (Vulpes lagopus) breeding den from the southern Arctic tundra of Yamal Peninsula, Russia in 2007. At the same time, as a current range retraction of the original inhabitant of the circumpolar tundra zone the arctic fox is going on, the red fox is expanding their range from the south into arctic habitats. Thus, within large parts of the northern tundra areas the two species are sympatric which gives opportunities for direct interactions including interference competition. However, direct first-hand observations of such interactions are rare, especially in the Russian Arctic. In the present study, we observed one red fox taking over an arctic fox breeding den which resulted in den abandonment by the arctic fox. On July 19, eight arctic fox pups were observed on the den before the red fox was observed on the same den July 22. The pups were never seen at the den or elsewhere after the red fox was observed on the den for as long as we stayed in the area (until August 10). Our observation supports the view that direct interference with red fox on breeding dens may contribute to the range retraction of arctic foxes from the southern limits of the Arctic tundra in Russia.     

Patterns and determinants of shorebird species richness in the circumpolar Arctic

Aim The intention with this study was first to investigate and describe the broad‐scale geographical patterns of species richness of breeding shorebirds (Charadriiformes; families: Charadriidae, Scolopacidae and Haematopodidae) throughout the arctic tundra biome. Secondly, after compensating for the positive relationship between net primary productivity (NPP) and species richness, the relative importance of additional ecological and historical variables for species richness was investigated. The main variables considered are NPP, length of snow‐ and ice‐free season, accessibility of regions depending on migratory flyway systems, tundra area at Pleistocene (120 and 20–18 ka bp ) and Holocene (8 ka bp ) times, and tundra area at present. Methods Information on shorebird species breeding distributions was compiled from distribution atlases and species accounts. The breeding distributions of shorebirds with ranges partly or completely in the Arctic (a total of 50 species) were mapped in ArcView 3.2 to create a raster grid layer of shorebird species richness at a 1° latitude × longitude resolution. The total and mean species richness value was calculated per each 10° of longitude sector of the Arctic. The relationships between species richness and the different climatic and environmental variables were analysed on the basis of this sector‐wise division of the arctic tundra. The influence of each variable on species richness was investigated using univariate and multivariate analyses (multivariate linear regression and general linear model). Results We found that patterns of breeding shorebird species richness in the Arctic tundra biome are to a large degree determined by the NPP, the length of the snow‐ or ice‐free season, the diversity of migratory flyways, as well as the historical extent of tundra habitat area during the maximum cooling of the last glacial period. Essentially, two main regions are distinguishable in the circumpolar Arctic regarding shorebird community richness. These are a species‐rich Beringia‐centred region and a species‐poor Atlantic‐centred region. Main conclusions The underlying explanations to these major trends may primarily be attributed to factors that operate at present through accessibility of areas from contemporary migration flyways, as well as processes that operated in the past during and after the last glacial cycle. The most prominent influence on the shorebird diversity was found for NPP in combination with the diversity of migratory flyways. These flyways provide the links between breeding and wintering resources, often separated by huge distances, and the geographical and ecological conditions associated with the shorebirds’ migration seem to be of particular importance for their breeding diversity in different sectors of circumpolar tundra.     

Modelled changes in arctic tundra snow,energy and moisture fluxes due to increased shrubs

In arctic tundra, shrubs can significantly modify the distribution and physical characteristics of snow, influencing the exchanges of energy and moisture between terrestrial ecosystems and the atmosphere from winter into the growing season. These interactions were studied using a spatially distributed, physically based modelling system that represents key components of the land–atmosphere system. Simulations were run for 4 years, over a 4‐km² tundra domain located in arctic Alaska. A shrub increase was simulated by replacing the observed moist‐tundra and wet‐tundra vegetation classes with shrub‐tundra; a procedure that modified 77% of the simulation domain. The remaining 23% of the domain, primarily ridge tops, was left as the observed dry‐tundra vegetation class. The shrub enhancement increased the averaged snow depth of the domain by 14%, decreased blowing‐snow sublimation fluxes by 68%, and increased the snowcover's thermal resistance by 15%. The shrub increase also caused significant changes in snow‐depth distribution patterns; the shrub‐enhanced areas had deeper snow, and the non‐modified areas had less snow. This snow‐distribution change influenced the timing and magnitude of all surface energy‐balance components during snowmelt. The modified snow distributions also affected meltwater fluxes, leading to greater meltwater production late in the melt season. For a region with an annual snow‐free period of approximately 90 days, the snow‐covered period decreased by 11 days on the ridges and increased by 5 days in the shrub‐enhanced areas. Arctic shrub increases impact the spatial coupling of climatically important snow, energy and moisture interactions by producing changes in both shrub‐enhanced and non‐modified areas. In addition, the temporal coupling of the climate system was modified when additional moisture held within the snowcover, because of less winter sublimation, was released as snowmelt in the spring.     

The distribution and diversity of Chironomidae (Insecta: Diptera) in western Finnish Lapland, with special emphasis on shallow lakes

Aim Predictions of aquatic ecosystem change with global warming require basic data that accurately reflect the environmental conditions underlying species distributions. However, in remote arctic areas such baseline data are scarce. We assess the influence of environmental variables on chironomid distribution and taxon richness in shallow, isothermal lakes in a poorly studied arctic region. We pay particular attention to community variation along the treeline ecotonal zone where many environmental variables change abruptly in a relatively small area. Location Lake transect in Finnish Lapland spanning from boreal coniferous forest to arctic tundra. Methods Chironomid assemblages were determined from surface‐sediment samples of 50 shallow (< 10 m) natural lakes. Abundance and taxon richness data were related to 24 limnological variables using canonical ordination techniques (DCA, CCA, RDA). A Monte Carlo permutation procedure was used to assess the explanatory power of single variables. Between‐vegetation zone differences of richness were tested for statistical significance using one‐way anova . Results In total, 7771 chironomid head capsules were identified, consisting of 13 species, 10 species groups, four subgenera, 41 genera, four genus groups, five types and three with uncertain taxonomic affiliation. A hump‐shaped relationship between taxon richness and elevation was noted along the study transect with a peak in taxon richness occurring in mountain birch woodland lakes at middle elevations, decreasing then towards both warmer and colder ends of the elevation/temperature gradient. Of the individual parameters, sediment organic content, total organic carbon, pH, and lake‐specific air temperature accounted for the greatest amount of variation in the chironomid data. Main conclusions Maximum taxon richness occurred at mid‐elevations where aquatic algae also reached their maximum diversity. This area coincides with an ecotonal transitional zone, which seems more likely to account for the peak in species richness. Our study demonstrates that the factors most strongly affecting chironomids in Finnish Lapland (i.e. temperature, and ecosystem features) are those that with great probability will also change as a result of future climate change. This will likely have an effect on the distribution of chironomids in subarctic and arctic areas.     

Scavenger community structure along an environmental gradient from boreal forest to alpine tundra in Scandinavia

Scavengers can have strong impacts on food webs, and awareness of their role in ecosystems has increased during the last decades. In our study, we used baited camera traps to quantify the structure of the winter scavenger community in central Scandinavia across a forest–alpine continuum and assess how climatic conditions affected spatial patterns of species occurrences at baits. Canonical correspondence analysis revealed that the main habitat type (forest or alpine tundra) and snow depth was main determinants of the community structure. According to a joint species distribution model within the HMSC framework, species richness tended to be higher in forest than in alpine tundra habitat, but was only weakly associated with temperature and snow depth. However, we observed stronger and more diverse impacts of these covariates on individual species. Occurrence at baits by habitat generalists (red fox, golden eagle, and common raven) typically increased at low temperatures and high snow depth, probably due to increased energetic demands and lower abundance of natural prey in harsh winter conditions. On the contrary, occurrence at baits by forest specialists (e.g., Eurasian jay) tended to decrease in deep snow, which is possibly a consequence of reduced bait detectability and accessibility. In general, the influence of environmental covariates on species richness and occurrence at baits was lower in alpine tundra than in forests, and habitat generalists dominated the scavenger communities in both forest and alpine tundra. Following forecasted climate change, altered environmental conditions are likely to cause range expansion of boreal species and range contraction of typical alpine species such as the arctic fox. Our results suggest that altered snow conditions will possibly be a main driver of changes in species community structure.     

Arctic fox versus red fox in the warming Arctic: four decades of den surveys in north Yukon

During the last century, the red fox (Vulpes vulpes) has expanded its distribution into the Arctic, where it competes with the arctic fox (Vulpes lagopus), an ecologically similar tundra predator. The red fox expansion correlates with climate warming, and the ultimate determinant of the outcome of the competition between the two species is hypothesized to be climate. We conducted aerial and ground fox den surveys in the northern Yukon (Herschel Island and the coastal mainland) to investigate the relative abundance of red and arctic foxes over the last four decades. This region has undergone the most intense warming observed in North America, and we hypothesized that this climate change led to increasing dominance of red fox over arctic fox. Results of recent surveys fall within the range of previous ones, indicating little change in the relative abundance of the two species. North Yukon fox dens are mostly occupied by arctic fox, with active red fox dens occurring sympatrically. While vegetation changes have been reported, there is no indication that secondary productivity and food abundance for foxes have increased. Our study shows that in the western Arctic of North America, where climate warming was intense, the competitive balance between red and arctic foxes changed little in 40?years. Our results challenge the hypotheses linking climate to red fox expansion, and we discuss how climate warming’s negative effects on predators may be overriding positive effects of milder temperatures and longer growing seasons.     

Temperature distribution in light-coloured flowers and inflorescences of early spring temperate species measured by Infrared camera

Temperature is a limiting factor for plant reproduction under harsh conditions. Using an infrared camera, we studied temperature distribution in three early flowering light-coloured species of markedly different morphology. The influence of three environmental factors (temperature of the ambient air, temperature of the ground and irradiance) on the temperature of the flowers and inflorescences was evaluated. White petals and yellow centres of sun tracking Anemone nemorosa (Ranunculaceae) were shown to be on average 1.6 and 3.4 °C warmer than the ambient air, respectively. The surface temperature of the sun lit yellow discs of Bellis perennis (Asteraceae) was on average 7.4 °C warmer than the ambient air. Direct solar light was found to be responsible for large temperature differences between the discs and the marginal ray flowers. Bell-shaped white flowers of Galanthus nivalis (Amaryllidaceae) bent to the ground were on average 2.7 °C cooler than the surrounding air. The temperature relations of the different reproductive organs to the studied environmental factors are discussed. Temperature behaviour of the studied lowland species is compared with the results previously gained for alpine and arctic species by other authors. Ecological importance of our conclusions is considered.