Wyniki wyszukiwania

1

Habitat segregation by moose in a boreal forest ecotone

100%

Miller B. K., Litvaitis J. A.

Acta Theriologica

|

1992

|

tom 37

|

nr 1-2

We examined seasonal borne range size and habitat use by sexes of moose Alces dices (Linnaeus, 1758) near the southern edge of this species' geographic range. Home range size did not differ between males and females during any season. The distribution of forage partly explained seasonal habitat use by both sexes. However, sites occupied by males in summer (1 Juno - 15 September) and autumn (16 September - 31 December) were at higher elevations, had steeper slopes, and were farther from potential aquatic feeding sites than sites used by females. We suggest that habitat segregation during these seasons was a consequence of differential resource requirements, not active avoidance by either sex. During summer, females occupied lowland sites near forest cuts, presumably because these sites had abundant forage and dense understory cover that concealed their young from predators. Additionally, females utilized roadside salt licks more often than males during summer and autumn. Males occupied upland hardwood stands during summer in an apparent effort to avoid heat stress and maximize forage intake. Habitat characteristics of both sexes were similar during winter when resource needs were probably equivalent, and the quality and distribution of forage were more homogenous.

2

Central European habitats inhabited by spiders with disjunctive distributions

72%

Ruzicka V.

Polish Journal of Ecology

|

2011

|

tom 59

|

nr 2

The purpose of the study is to find which habitats within Central Europe support the persistence of isolated populations of spider species of both boreal and Alpine origins. Twenty-five species exhibited disjunctive distributions with their main sub-area in the tundra or boreal forest, and isolated sub-areas in the temperate zone of Central Europe. Six species exhibited disjunctive distributions with their main sub-area in the Alps, and isolated sub-areas in the temperate zone in Central Europe. Only (approximately) one-third of the species of boreal origin have the same habitat, as in the boreal zone. Twothirds of the species inhabit different habitats, or have narrowed their ecological valency. Screes play an important role in the survival of these isolated populations of species of boreal origin in the temperate zone, together with mountain summits, mountain forests, and peat bogs. Extensive complexes of sandstone rocks also enables the survival of isolated populations of species of boreal origin.

3

Nest site and nest-hole characteristics used by Great Spotted Woodpecker Dendrocopos major L. in Croatia

72%

Cikovic D., Barisic S., Tutis V., Kralj J.

Polish Journal of Ecology

|

2014

|

tom 62

|

nr 2

Great Spotted Woodpecker is the most abundant and widespread European woodpecker species, and it thus contributes the most to the number of excavated tree holes – an important habitat resource for secondary hole users. However, majority of nest site characteristics data comes from boreal and temperate forests, with lack of information from Southern Europe. In this article, nest sites of the Great Spotted Woodpecker have been investigated in the continental forests of Croatia – a previously understudied area of this species’ range. A total of 41 active nest-holes found in the breeding seasons 2003 and 2004 are described. Nest-holes were mainly positioned below the crowns, in injuries of branch abscission. Nesting tree species were not used randomly: wild cherry Prunus avium in hill and pedunculate oak Quercus robur in riverine forests were preferred while hornbeam Carpinus betulus and maples Acer sp. were avoided. While tree species used for nesting vary across the Great Spotted Woodpecker range, and thus cannot be used as a uniform nest site predictor, defected wood spots on a tree, like scars of branch abscission, are identified as an important nest site clue and a habitat feature that is spatially more consistent. Nest-holes’ dimensions acquired in this research could not be clearly differentiated from those given for the other parts of the continent.

4

The abundance of tree holes and utilization by hole-nesting birds in a primeval boreal forest of Mongolia

72%

Bai M. L., Wichmann F., Muhlenberg M.

Acta Ornithologica

|

2003

|

tom 38

|

nr 2

The natural tree holes and nest holes of hole-nesting birds were surveyed in four forest types in the west Khentii Mountains of NE Mongolia. The utilization patterns of species, size and condition of trees, as well as hole types, were investigated. The average density of tree holes in the study area approached 30 holes/ha, while that of hole-nesting birds was 2.4 nests/ha only. The riparian mixed forest had the greatest number of species and individuals of hole-nesting birds, while the spruce-fir forest had the lowest numbers. Excavating bird species preferred larger, deciduous trees, and snags. Non-excavators did not select holes according to tree species or size, but preferred holes in living trees and branch holes. In view of the low occupancy of holes among the four habitats, we suggest that the density of secondary hole-nesting birds is not limited by availability of holes in the study area.

5

Descriptions of Phryganella laurentiana n.sp. and Difflugia yorkui n.sp. two new species of testate amoebae from boreal forest wetlands in Ontario, Canada

72%

Nicholls K. H.

Acta Protozoologica

|

2007

|

tom 46

|

nr 1

6

The bryophytes of peatlands in continental western Canada

72%

Vitt D. H., Belland R. J.

Fragmenta Floristica et Geobotanica

|

1995

|

tom 40

|

nr 1

7

Local diversity versus geographical distribution of arthropods occurring in sandstone rock labyrinth

58%

Ruzicka V., Mlejnek R., Smilauer P.

Polish Journal of Ecology

|

2010

|

tom 58

|

nr 3

Rocks have been overlooked as subjects for ecological study. However, the system of narrow and deep vertical spaces (gorges, crevices, abysses) in sandstone rocks supports a highly diverse mosaic of habitats. The patterns of air temperatures and the assemblages of arthropods were studied along the environmental gradient in the Poseidon Sandstone Labyrinth within the Adršpašsko-Teplické Skály National Nature Reserve, NE Bohemia, Czech Republic. The labyrinth, developed in Cretaceous sandsones at an altitude of about 600 m, is approximately 740 m long and 550 m wide. It consists of a broken, interconnected network of deep vertical crevices, crevice caves, and talus caves in extensive block accumulations. The total length of the human-accessible underground spaces is estimated to be at least 27 km, the vertical range is 105 m. The annual course of air temperature was monitored on the sun-exposed upper rock margin (max. 26.5°C, min. –7.3°C, mean 6.1°C), as well as in the cold and dark crevice cave (max. 9.6°C, min. –1.9°C, mean 3.7°C). Due to the climatic inversion in the deep vertical spaces, mountain bryophytes and vascular plants occur here. A total of 2285 arthropods belonging to eight taxonomic groups were evaluated; spiders and beetles were the most numerous. We registered 304 species, which colonize the totality of habitats in the labyrinth: cold bottom parts, dark caves, shady rock walls, as well as the sun-exposed upper rock margins. The cold parts of the labyrinth harbour populations of sixteen species of mountain arthropods (beetles, spiders and a harvestman) and five species of arthropods with distributions in tundra or boreal forests, and similar disjunctive habitats in the temperate zone in central Europe (spiders and a mite). The first record of the Arctic predatory mite Rhagidia gelida in central Europe was in the Poseidon Labyrinth in 1986; this species proved to be a bio-indicator of the long-lasting periglacial microclimate in central Europe. Prior to discovery of the spider Sisicus apertus in the Poseidon Labyrinth, it had been recorded in central Europe in the Alps and in the High Tatra Mountains at altitudes of 1150 to 2300 m. At the present time, we consider the Poseidon Sandstone Labyrinth to be a paleorefugium of cold-adapted arthropods.

8

Seasonal diets of red foxes in a boreal forest with a dense population of moose: the importance of winter scavenging

58%

Needham R., Odden M., Lundstadsveen S. K., Wegge P.

Acta Theriologica

|

2014

|

tom 59

|

nr 3

In Scandinavia, an increased red fox Vulpes vulpes density during the last decades has been suggested to be caused by direct and indirect human influences on food availability. Recently, attention has been focused on the role of increasing scavenging opportunities due to intensified hunting of ungulates and the reestablishment of large carnivores. In our study, we investigated seasonal and annual variations in diet composition of red fox in Varaldskogen, SE Norway, an area with cyclic voles and a high density of moose Alces alces. Analyses of scats revealed significant differences among seasons in the occurrence of ungulates—mainly moose—and ungulates were the dominating food category during winter (44.9 % of all remains). Snow tracking of red fox (71 km) in winter confirmed the importance of ungulate carcasses, i.e. one case of scavenging per 3 km. The proportions of voles were high during all seasons (11.2–28.8 %); in spite of variation in available abundances, no significant seasonal or annual differences were detected. Other food categories with seasonal variation were birds, berries/seeds and amphibians/reptiles, all more common in snow-free seasons. Our study underlines the importance of ungulate remains during periods when the abundance and diversity of alternative food sources is low. Increased and stabilized populations of red foxes—mediated through remains from hunting and wolf kills from high moose populations—might have an important effect on the population dynamics of small game. Hence, we recommend that this relationship be given attention in future studies.

9

Nitrogen deposition and flux through birch stands [Betula pubescens Ehrh.] in the Kampinos National Park [Central Poland]

58%

Kram K. J.

Polish Journal of Ecology

|

2008

|

tom 56

|

nr 4

605-612

Nitrogen flow through birch stand canopies was studied in the Kampinos National Park (large forested area with inland dunes and wetlands close to Warsaw) during the growing seasons (April-October) of 2005–2006. The amount of nitrogen deposition including main forms like NO₃, NH₄, organic N and the aerosolgaseous fraction of deposition were estimated as well as the influence of birch canopies on this process. Because a method of “artificial foliage” allows to measure an aerosol-gaseous fraction of deposition a gradient of rain collectors equipped with artificial foliage of known surfaces were used. The results were compared with amounts of nitrogen measured in the throughfall of three birch forests. All stands (age 20–50 years) were rather similar, but stand II has smaller LAI (Leaf Area Index = 2.5 m² m⁻²) than stands II and III (3.8 and 3.9 m² m⁻²). It was found that nitrogen deposition in the Kampinos National Park is rather high – 1.6 kg ha⁻¹ month⁻¹. Ammoniumnitrogen made almost half of this value, organic nitrogen – over one third, and nitrate-nitrogen constituted the rest. Aerosol-gaseous input significantly made the deposition increased only in the case of nitrate-nitrogen, but deposition of ammonium- and organic nitrogen were similar and independent of catching leaf area. All fractions of nitrogen were effectively taken up during their passing through birch canopies (57% of nitrogen deposition was retained). Generally two thirds of deposited ammonium-nitrogen, more than half of organic N, and one third of nitratenitrogen were taken up by birch canopies. However, uptake efficiency of all N forms was lower for stand with smallest leaf area with no statistically significant retention of organic N.

Ograniczanie wyników

Habitat segregation by moose in a boreal forest ecotone

Central European habitats inhabited by spiders with disjunctive distributions

Nest site and nest-hole characteristics used by Great Spotted Woodpecker Dendrocopos major L. in Croatia

The abundance of tree holes and utilization by hole-nesting birds in a primeval boreal forest of Mongolia

Descriptions of Phryganella laurentiana n.sp. and Difflugia yorkui n.sp. two new species of testate amoebae from boreal forest wetlands in Ontario, Canada

The bryophytes of peatlands in continental western Canada

Local diversity versus geographical distribution of arthropods occurring in sandstone rock labyrinth

Seasonal diets of red foxes in a boreal forest with a dense population of moose: the importance of winter scavenging

Nitrogen deposition and flux through birch stands [Betula pubescens Ehrh.] in the Kampinos National Park [Central Poland]