The breeding success of a nest-box breeding population of Pied Flycatcher Ficedula hypoleuca in subalpine birch forest in Swedish Lapland was studied over 55 years, with emphasis on the impact of small mustelids and ambient temperature during egg laying, incubation, and brood care. The proportion of nests predated was used as an index for mustelid abundance. Breeding failures were either total, due to breeding interruptions, or partial due to partial hatching failure or nestling death. Overall, mustelid abundance explained the rate of breeding interruptions at any breeding phase, but not when seasons with exceptional (>10%) predation rates were excluded. Variation in the rate of partial failure was unrelated to mustelid abundance. Climatic conditions affected clutch size, rate of breeding interruption, and partial loss of clutches or broods, with particularly pronounced effects during the incubation period. The mustelid abundance and weather conditions also influenced rates of nest-box occupation in subsequent breeding seasons, and the next-box population dynamics covaried with surrounding populations.

Distribution patterns of biodiversity and environmental interactions are dominant themes in ecology. In montane ecosystems, biodiversity is closely associated with altitudinal gradients. However, studies of biodiversity in montane ecosystems are focused on plants and vertebrates, with relatively less on invertebrates. Here, the present study used a Vortis arthropod suction sampler to explore the biodiversity patterns of soil surface‐dwelling Oribatida and their drivers along an altitudinal gradient (600, 800, 1600, 2000, and 2300 m) from typical temperate forests, evergreen coniferous forests, subalpine birch forests to alpine tundra on the north slope of Changbai Mountain, Northeast China. Trichoribates berlesei, Platynothrus peltifer, and Oribatula tibialis were the dominant soil surface‐dwelling species on Changbai Mountain. Generally, alpha diversity and beta diversity of soil surface‐dwelling Oribatida decreased with the rising altitude, with a peaking density value at 2000 m. The result of beta diversity showed that the structures of community were more influenced by the species turnover component than the nestedness component. Nonmetric multidimensional scaling (NMDS) ordination showed that the community structure of soil surface‐dwelling Oribatida varied significantly along the altitudinal gradient. The variance partitioning showed that the elevation and climatic conditions determined the soil surface‐dwelling Oribatida community. Spatial filtering represented by geographic and elevation distances was particularly associated with soil surface‐dwelling Oribatida community variation between altitudes on Changbai Mountain. However, the variation of the Oribatida community between adjacent altitudes was only associated with geographic distance. Our study provides supportive evidence for the biodiversity analyzing of soil surface‐dwelling Oribatida in montane ecosystems along an altitudinal gradient.

Abstract Dramatic declines of some arthropod populations have recently received a lot of attention. Identified declines have mainly been attributed to changes in agriculture, climate, pathogen prevalence and light pollution, as well as cross‐regional effects of, e.g., drifting pesticides. However, the overall picture is complex and debated, and there is a need for systematically collected long‐term data, not least from areas relatively unaffected by humans. We monitored the abundance of arthropods (mainly insects) in subalpine birch forest in Swedish Lapland over a period of 53 years (1968–2020), in an area comparatively unaffected by human activities. Arthropod abundance was assessed by yearly systematic counts on 24,000 birch shoots, in the second half of June. Animals were categorised into 17 different groups directly upon counting, dependent on taxonomy and life stage (imago, larva). Overall, there was no significant change in arthropod numbers. Nor did estimates of the total biomass of arthropods (using group‐specific indices of the mass of individuals) show any significant trend. Accordingly, there are no signs that the arthropod abundance or biomass on birch in this subarctic study site has gone through the same declines as have been reported from sites in other habitats. The reason may be that the impact of factors identified worldwide as drivers of arthropod declines so far are small or non‐existent because of the low human population density in this area.

Mountains harbour high biodiversity that is facing a crisis due to recent climate change. Bird communities shift along mountain gradients. Some previous studies have suggested that the effect of vegetation is prevalent on temperate mountains. In this study, we investigated the limiting effects of vegetation on the altitudinal distribution of birds on Mount Norikura in central Japan, by comparing bird communities along four gradients of different orientations. We recorded birds using the line-transect method and classified vegetation into six types: montane deciduous broadleaved forest, subalpine coniferous forest, subalpine birch forest, Japanese Stone Pine scrub forest, alpine tundra and bare ground below the alpine area.We identified the treelines and ecotones between the predominant vegetation types along each gradient. We found that bird species composition changed drastically at the treeline along three gradients. A non-metric multidimensional scaling (NMDS) ordination revealed: 1) the similarity between bird community structures in the subalpine coniferous forest and the Japanese Stone Pine scrub forest differed among the gradients, 2) despite birch being broadleaved, the bird community in the subalpine birch forest was a subset of that in the subalpine coniferous forest and was more similar to that in the subalpine coniferous forest than that in the montane deciduous broadleaved forest, and 3) in upper parts of the subalpine zone, the bird community structures in the subalpine coniferous and birch forests were similar to each other.Our findings suggest that although the treeline limits the distribution of forest-dwelling bird species, this effect differs among gradients with different orientations, probably depending on the scrub height of the Japanese Stone Pine scrub forests. Furthermore, the heterogeneity of coniferous and birch forests in the upper parts of the subalpine zone may have little effect on the altitudinal distribution of birds.

The article presents the results of studying the coenoflora of the mountain birch forests found in the Teberdinsky State Natural Biosphere Reserve (Karachay-Cherkessia). The work shows the current state and composition of the cenoses dominated by Betula litwinowii Doluch on the Reserve. The material to analyse the coenoflora was based on 45 standard geobotanical descriptions of 2 types of birch forests: the birch crooked forests in the upper part of the subalpine belt and the secondary birch forests on the places of disturbed indigenous cenoses in the forest belt. The range of heights of distribution of the studied cenoses above the sea level is 1,660 m – 2,260 m. The main types of flora analysis were performed: the general characteristics of the flora, the geographical analysis, the study of the biomorphological, phytocenotic and ecological spectra. The coenoflora of the studied birch trees consists of 326 species that belong to 176 genera, 66 families and 6 classes, which is 14.5% of the flora of Karachay-Cherkessia. According to the main biomorphological features, the ecological characteristics, and the predominant geographical elements, the coenoflora of birch forests of the TSNBR is similar to the regional flora. The leading role of the Fabaceae family, combined with its high content of the Ancient Mediterranean elements in the coenoflora of the Reserve’s birch trees, can be explained as the nature of the flora of the whole region and the increased influence of the TSNBR Mediterranean floras on the birch coenoflora formation. The significant role of species of the meadow ecological and phytocenotic group is explained by the predominance of thinned subalpine birch forests in the TSNBR.

A new species, Hygrophorus betulae, associated with Betula pubescens is described from the subalpine zone of northern Finland. The molecular phylogenetic analysis shows that it is closely related to H. mesotephrus, a species described from England and associated with Fagus. In morphology H. betulae is characterized by the small glutinous basidiomata and the pale pileus with an olive-grey disc zone. The colour of the disc zone is similar to that of H. olivaceoalbus. The species seems to be rare or may be overlooked because of the small and pale appearance.

Northern taiga forests and subalpine plant communities of the Laplandskiy State Nature Biosphere Reserve (Kola Peninsula, Russia) were surveyed for myxomycetes. A total of 1675 specimens of myxomycete fruit bodies (sporocarps) were registered, among them 1584 records from field collections and 92 obtained from 210 moist chamber cultures of ground litter, bark of living trees, wood, and weathered dung of moose and willow ptarmigan. Most of 125 taxa (124 morphospecies and one variety) representing 34 genera were recorded only in the field (104 taxa from 32 genera), but some were exclusively obtained from moist chamber cultures (8 taxa from 5 genera). All of the recorded species are new for the Laplandskiy Reserve. Species numbers decreased among the four studied forest associations along the elevation and mositure gradient, and the Shannon index showed a similar trend: spruce forest (PICa; 84 taxa, H’=3.8), spruce-peat moss forest (PICb; 70, 3.5), dry spruce-pine forest (PIN; 62, 3.7), subalpine birch forest (SB; 30, 2.7). The estimated completeness of the survey according to the Chao1 estimator was 66%, indicating that most of the more common species should have been recovered. The trend among forest associations runs mainly parallel to diversity: PICa and PICb 83%, PIN 47%, SB 57%. The myxomycete assemblage of dry coniferous forests is the most distinctive among the three forest types and shows the highest number of indicator species. The overall degree of specialization of myxomycetes is higher for substrate type than for forest associations. Among substrate types, species diversity and richness increase from litter over bark to wood.

Return rates of 4,178 female and 1,565 male breeding Pied Flycatchers ringed in 1965–2017 were studied near the species’ upper elevation and climatic limit in northern Sweden. Female return rate was 7.5% in the season subsequent to the first breeding season. Having returned once, 37% continued to return the next three seasons. Corresponding return rates of males were 27% and 39%. Female return rate decreased with more than 30% during the study period whereas that of males did not decrease. This difference was probably due to increased mortality during the non-breeding season that selectively struck females after the 1970s. Local factors affected return rates in both sexes. Return rate was positively correlated with breeding success in females but negatively in males, whereas it was correlated with nest-predation in the opposite way. Predation by mustelids accounted for a significant part of female return rate. Females that had returned once were continuously faithful to the former breeding site. Males showed faithfulness only after having returned twice.

Near real-time monitoring of insect induced defoliation in subalpine birch forests with MODIS derived NDVI

Newly laid eggs of Pied Flycatchers Ficedula hypoleuca breeding in subalpine birch forest in Swedish Lapland were weighed in the field in 1965–1976. The main objective of the study was to get knowledge of the egg production capacity and its relation to the environmental conditions in the northern periphery of the breeding range of the species. The eggs were on average smaller than what is known from other Pied Flycatcher populations. Egg mass was non-linearly related to ambient temperature, and smallest at temperatures <10°C. About 70% of the eggs were laid at those temperatures. Variation in temperatures during the egg formation contributed to a significant egg mass variation between years. Average egg mass was lowest in the biggest clutches (7 or 8 eggs). Egg mass did not vary significantly within clutches, was not significantly related to the female mass, and did not vary between years in the same female. Hatching and fledging success were non-significantly related to the mean egg masses, indicating that egg sizes were not decisive for the breeding output.

The northern slopes of the Central Great Caucasus of Georgia were covered by birch (Betula litwinowii ) forests in the past, but forest degradation resulted in subalpine secondary meadows. Over the past 20 years birch forest natural reforestation processes have taken place. The aim of this study was to determine the changes in plant species diversity during reforestation. Different habitat types were selected to trace the development of birch forests from subalpine meadows. Species richness was determined in 100 research plots (25 m 2 each) of different habitat types. Pioneer succession was distinguished by the highest level of species richness due to the mixture of two habitat types. Degraded forest showed the lowest species richness. At the initial stages of forest restoration we observed several species of subalpine dwarf shrubs. They grow only in open canopy areas and are absent in closed forests. The alpine treeline habitat type and pioneer succession of subalpine meadows revealed close relations in species composition and diversity. These similarities show forest restoration in lower elevations as it is restricted in the treeline ecotone by local climatic conditions. The natural regeneration is apparently in close relation with the global climate change, but the most important factor is the reduction of uncontrolled sheep grazing.

In order to understand the use and control of resources by indigenous households and bands, information on territorial division is crucial. However, although indigenous resource use has been quantified in several studies, such information has usually been lacking. A unique map provides this kind of information for the Swedish Sami. Drawn by Jonas Persson Gedda in 1671, before the Swedish state started to interfere with Sami territorial division, it shows the borders of 37 household territories. We have combined the geographical information from Gedda’s map with historical sources and modern land survey data to quantify the resources controlled by each household and relate them to taxation. Three crucial resources are identified: alpine heath together with subalpine birch forest, pine-dominated forests, and fishing waters. Only the fishing resource showed any correlation to taxation, which underlines its importance as the main subsistence mode, at least for the forest Sami. Mountain Sami, who lived primarily on reindeer husbandry, controlled abundant alpine heath and subalpine birch forests that were used as summer pastures, but virtually no pine-dominated forests with winter pastures. The necessary winterpastures were located in the territories of the forest Sami, who controlled extensive pine-dominated forests and who were able to combine reindeer herding and wild reindeer hunting.

Large‐scale multi‐species data on population changes of alpine or arctic species are largely lacking. At the same time, climate change has been argued to cause poleward and uphill range shifts and the concomitant predicted loss of habitat may have drastic effects on alpine and arctic species. Here we present a multi‐national bird indicator for the Fennoscandian mountain range in northern Europe (Finland, Sweden and Norway), based on 14 common species of montane tundra and subalpine birch forest. The data were collected at 262 alpine survey plots, mainly as a part of geographically representative national breeding bird monitoring schemes. The area sampled covers around 1/4 million km 2 , spanning 10 degrees of latitude and 1600 km in a northeast–southwest direction. During 2002–2012, nine of the 14 bird species declined significantly in numbers, in parallel to higher summer temperatures and precipitation during this period compared to the preceding 40 yr. The population trends were largely parallel in the three countries and similar among montane tundra and subalpine birch forest species. Long‐distance migrants declined less on average than residents and short‐distance migrants. Some potential causes of the current decline of alpine birds are discussed, but since montane bird population sizes may show strong natural annual variation due to several factors, longer time series are needed to verify the observed population trends. The present Fennoscandian monitoring systems, which from 2010 onwards include more than 400 montane survey plots, have the capacity to deliver a robust bird indicator in the climate‐sensitive mountainous regions of northernmost Europe for conservation purposes.

The postglacial tree line and climate history in the Swedish Scandes have been inferred from megafossil tree remains. Investigated species are mountain birch (Betula pubescens ssp. czerepanovii), Scots pine (Pinus sylvestris) and grey alder (Alnus incana). Betula and Pinus first appeared on early deglaciated nunataks during the Lateglacial. Their tree lines peaked between 9600 and 9000 cal. a BP, almost 600 m higher than present‐day elevations. This implies (adjusted for land uplift) that early Holocene summer temperatures may have been 2.3°C above modern ones. Elevational tree line retreat characterized the Holocene tree line evolution. For short periods, excursions from this trend have occurred. Between c. 12 000 and 10 000 cal. a BP, a pine‐dominated subalpine belt prevailed. A first major episode of descent occurred c. 8200 cal. a BP, possibly forced by cooling and an associated shift to a deeper and more persistent snow pack. Thereafter, the subalpine birch forest belt gradually evolved at the expense of the prior pine‐dominated tree line ecotone. A second episode of pine descent took place c. 4800 cal. a BP. Historical tree line positions are viewed in relation to early 21st century equivalents, and indicate that tree line elevations attained during the past century and in association with modern climate warming are highly unusual, but not unique, phenomena from the perspective of the past 4800 years. Prior to that, the pine tree line (and summer temperatures) was consistently higher than present, as it was also during the Roman and Medieval periods, c. 1900 and 1000 cal. a BP, respectively.

A nest-box breeding population of Pied Flycatcher Ficedula hypoleuca in subalpine birch forest at Ammarnäs in northern Sweden was studied in 1965–2010. The population showed on average a significantly decreasing trend during the initial 25 years, after which it remained on a static level. The yearly variation of the population size was significantly correlated with breeding result in preceding years, which in turn was affected by e.g. nest predation, adverse climatic factors, clutch size, and incidence of defective egg shell formation. It is also suggested that the population decline during the initial 10–15 study years followed from over-establishment of the breeding habitat. The average breeding result was 2.3 fledglings per pair, which is far below the number needed for the population to be self-reproducing. The occurrence of unusually high rates of nest predation and defective egg shells seems to be passing phenomena, predicted to approach zero after about 30 and 60 years, respectively, after the start of the study. But even with these factors eliminated and with other conditions remaining unchanged, the Ammarnäs population will continue to be a sink population.

A Fieldfare population, on average c. 160 pairs, was studied in subalpine birch forest in southern Lapland (c. 66°N; 500–600 m.a.s.l.) in 1983–2002. Onset of egg-laying showed no temporal trend, consistent with absence of spring temperature trend. Eggs were laid with an interval of c. 21 hours and 45 minutes, not 24 hours as normal in passerines. This reduces the exposure time to depredation during egg-laying with 9%. Egg hatchability was 96%. Egg parasitism never occurred. Depredation of nests was 46%, but very variable. Replacement and second clutches did not occur. Although an average of 4.45 young fledged from successful nests (≥1 fledgling), only 2.11 fledglings were produced per pair and year. The population varied without trend over the study period. Adult survival, estimated by the proportion of adults at the start of breeding, was 58%. This infers that first year survival must be at least c. 40%. Since this is a likely value, it seems that the Fieldfare population of the subalpine birch forest is selfsustained and not dependent upon immigration.

Aspects of the Holocene history of the subalpine birch (Betula pubescens Ehrh. ssp. tortuosa (Ledeb.) Nyman) forest belt in the Scandes Mountains, Sweden, were analysed by radiocarbon dating of subfossil wood remnants forming an enclave high above the present-day birch limit. The birch population thrived continuously at the site throughout the period 8700-3400 years BP, suggesting the absence of major protracted coolings and mostly higher than present temperatures. Presumably, the disappearance of birch from the study site ca. 3400 BP, reflects substantial cooling, which is corroborated by indépendant proxy data. It is inferred that during the first few millennia of the Holocene, pine (Pinus sylvestris L.) formed the uppermost forest belt and pure birch stands were restricted to small enclaves with excessive and late-melting snow. Eventually, as climate cooled, these conditions became regionally ubiquitous and birch could spread from the pockets of favourable habitat to form the present-day subalpine birch forest belt above the coniferous forest. In the original pockets too much snow accumulated and there the birch perished.

ABSTRACTThe availability of seeds and microsites are limiting factors for many plant species of different vegetation types. We have investigated the existence of such limitations in two habitats, an alpine heath and a subalpine birch forest, where abiotic factors are hypothesized to be the main determining factor of plant species distributions. Both habitats are characterized by a short growing season and cold temperatures, and the alpine heath is also constrained by low productivity. A seed addition experiment including six vascular plants, selected by different functional traits and occurrence, showed that seed limitation was an important factor in these habitats. Removal of the aboveground biomass (controlled disturbance) increased germination only for some species. The effect of reindeer presence was found to be of less importance, probably due to low and varying densities of reindeer. To conclude, we found that seed limitation was the most important factor limiting the distribution of our studied species in the two alpine environments.

Annual pollen accumulation rate (PAR) at the boreal and alpine forest-line of north-western Norway, with special emphasis on Pinus sylvestris and Betula pubescens

The Leaf Size–Twig Size Spectrum of Temperate Woody Species Along an Altitudinal Gradient: An Invariant Allometric Scaling Relationship