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1
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Species richness and spatial heterogeneity of spring plankton in a lake with varying morphometry

100%
Budzynska A., Szelag-Wasielewska E.
Acta Agrophysica
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2006
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tom 07
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nr 2[133]
2

Spatial heterogeneity of soil seed banks in sandy grasslands under fencing and grazing in Horqin sandland, Northern China

84%
Zuo X., Zhao X., Zhao H., Zhang T., Wang S., Knops J., Kochsiek A.
Polish Journal of Ecology
|
2013
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tom 61
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nr 2
Understanding composition, structure and spatial heterogeneity in soil seed banks is important for the management of grassland ecosystem. Although the effect of fencing and grazing on vegetation composition is widely known, information on species composition, seed density and spatial heterogeneity of soil seed banks in sandy grasslands under fencing and grazing is still lacking. We measured the species composition and seed density of soil seed banks in fenced grassland, grazed grassland and grazed shrubby grassland in Horqin Sand Land, Northern China. By applying the geostatistical methods, we assessed how fencing and grazing affected spatial heterogeneity of soil seed banks in sandy grasslands. Total seed density and species richness in soil seed banks were lower in fenced grassland than in either grazed grassland or grazed shrubby grassland. Seed density and species richness of annual species in soil seed banks were also lower in fenced grassland than in either grazed grassland or grazed shrubby grassland, while those of perennial species showed a reverse trend. The analysis of spatial autocorrelation ranges, fractal dimensions and distribution pattern maps from geostatistical methods showed that spatial heterogeneity of seed density and species richness in soil seed banks were also lower in fenced grassland than in either grazed grassland or grazed shrubby grassland. Continuous fencing increases the seed density and species richness of perennial species in soil seed banks, as well as results in a decrease in spatial heterogeneity of seed density and species richness in soil seed banks. So, continuous fencing should be considered to restore the degraded sandy grasslands in management of semiarid grassland ecosystems.
3

The importance of forest patches in supporting steppe-species: a case study from the Carpathian Basin

84%
Erdos L., Tolgyesi C., Kormoczi L., Batori Z.
Polish Journal of Ecology
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2015
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tom 63
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nr 2
Moderating effects of trees on the environment in their immediate proximity are considered an important force in structuring plant communities, especially in harsh environments. In the semi-arid regions of the middle Carpathian Basin, such facilitative influences are expected to become crucial for the survival of several plant species, given the current warming and drying tendencies. We used 20 × 20 m plots to analyze whether grassland species adapted to mesic conditions penetrate forest patches, where they are able to survive. Using transects and the moving split window analysis, we also investigated how far the positive effects of the forest patches extend into grasslands, and whether this enables the existence of a steppe community that cannot tolerate extreme dry conditions and unfavorable soils. We found that beside forest-related species, forest patches hosted large numbers of grassland-related species. Among them, plants of closed steppe grasslands were the most numerous, which usually cannot tolerate the harsh conditions of open sandy grasslands, and are often confined to areas with better water and soil conditions. Our results showed that there is a 5–8 m wide closed steppe zone around the forest patches. Some species that are not able to survive in open xeric sandy grasslands are restricted to this zone. Unfortunately, while considerable attention is paid to the research, protection and restoration of sandy grasslands, forest patches are usually neglected. Our results emphasize that the establishment of individual trees and groups of trees should be actively promoted, because they have considerable nature conservation benefits by supporing closed steppe species.
4

Species abundance-distribution relationship: the differences among oak (Quercus liaotungensis Koidz) forest layers

84%
Feng Y., Ma K., Zhang Y., Anand M., He K.
Polish Journal of Ecology
|
2011
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tom 59
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nr 1
Species abundance-distribution relationship is currently a hot topic in community ecology. Previous studies have suggested that a positive abundance-distribution relationship is a widespread feature of ecological assemblage across a wide variety of organisms, but how this relationship varies among different functional groups remains unclear. In this study, the species abundance-distribution relationship in the tree layer, shrub layer, and herb layer were analyzed respectively in an oak forest (Quercus liaotungensis Koidz.), Beijing region, China. Ten transects were set up from the foot to the top of every west slope to create a continuous altitude gradient (1020– 1770 m). The width of each transect was 10 m and the length of each transect ranged from 80–200 m, depending on the altitude range and slope degree. This study area consisted of 119 quadrats, each 10 × 10 m2. Within each quadrat, three sub-quadrats (1m × 1m) were randomly selected for the inventory of herb layer. Our results showed that the relationship between local species abundance and the regional distribution was significantly positive while the frequency distribution was unimodal in the three layers, indicating that locally abundant species were widely spread whereas locally rare species had restricted regional distributions. Variance partitioning of species abundance showed that the contribution of environmental variation and spatial variation to regulating the species abundance-distribution relationship of different layers are different: the pure geographical variation decreased and the pure soil variation increased in the order of tree layer, shrub layer, to herb layer, while the response due to total soil variation was similar in all three layer communities. The distribution of tree layer and shrub layer are mainly influenced by large-scale factors while herb layer distribution is more likely determined by local-scale factors.
5

Diversity of aquatic molluscs in a heterogenous section of a medium-sized lowland river-floodplain system: an example of intermediate disturbance hypothesis

84%
Jurkiewicz-Karnkowska E.
Polish Journal of Ecology
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2015
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tom 63
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nr 4
Natural river-floodplain systems are heterogenous mosaics of lotic and lentic habitats subjected to dynamic temporal changes connected with hydrological regime, which promote high biological diversity. Mollusc assemblages of three habitat types within 10 km section of the lower course of the Liwiec River (East Poland) — the main river channel (MC), the secondary channel (SC) and remnants of the former river channel (FC), were compared to find if they were structured by heterogeneity resulting from hydrological connectivity and disturbance intensity related to it. The influence of selected qualitative environmental variables was also analysed. The investigations were carried out at 19 sites during late spring and late summer in the years 2012–2014, molluscs were sampled from approximately 1 m² of the bottom with a hand net, and from macrophytes with a frame. Rich aquatic malacofauna (36 species including 22 gastropods and 14 bivalves) was found within the study area including three species of special interest: Anisus vorticulus (Troschel), Unio crassus Phillipsson and Anodonta cygnea (L.). Bivalves Sphaerium corneum (L.) and Pisidium spp dominated within MC, in SC a few common and ubiquitous species (mainly snails) prevailed, pulmonate snails and some small bivalves of the genus Pisidium were the most numerous molluscs within FC. Principal Component Analysis revealed that current velocity, channel width, bottom sediments and macrophyte abundance were important environmental factors structuring mollusc assemblages. Considerable variation in species composition (β diversity), especially between the main river channel and two other habitat types (β²) was found. The highest values of mean species richness, Shannon true diversity and Shannon index found in the secondary channel were in accordance with intermediate disturbance hypothesis.
6
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Recent multiyear trends in the Baltic Sea level

84%
Stramska M., Chudziak N.
Oceanologia
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2013
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tom 55
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nr 2
7

Effects of environmental and spatial heterogeneity on tree community assembly in Baotianman National Nature Reserve, Henan, China

84%
Jia H.-R., Chen Y., Yuan Z.-L., Ye Y.-Z., Huang Q.-C.
Polish Journal of Ecology
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2015
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tom 63
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nr 2
The debate on species coexistence mechanisms never stops. The niche theory, neutral theory, and negative density dependence mechanism has been attracting considerable attention in recent years, but an integrated research on species coexistence mechanisms has rarely been conducted. In this study, a previous investigation at a plot in Henan Province was used as a basis to analyze the spatial structure of the community with principal coordinates of neighbor matrices (PCNM). Variance partitioning was used to analyze the effects of topography, soil, spatial, and stand density on species distribution. Results show that the community structure in the broad, medium, and fine scales generally showed a highly significant spatial structure. Topography, soil, spatial variables, and stand density explained 3.4, 11.7, 12.1 and 19.49% of species distribution, respectively. The aforementioned results suggest that spatial factor was an important factor that affects community structure. Species distribution was evidently influenced by environmental spatial heterogeneity. It had a very important function for density-dependent effects acting on species distribution. Niche theory, neutral theory, and negative density dependence mechanisms affected community building in different degrees.
8

Nematode abundance, diversity and trophic structure in relation to spatial heterogeneity of a natural fen

84%
Ilieva-Makulec K.
Polish Journal of Ecology
|
2004
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tom 52
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nr 3
Spatial distribution of nematode fauna was studied in relation to horizontal heterogeneity of a natural tall-sedge fen in north-eastern Poland. Due to vegetation patchiness at scale of several tens centimetres two distinct habitats can be distinguished – “tussocks” and sites “between tussocks”. Nematode fauna in the soil “between tussocks” was different from that of the adjacent “tussocks” sites with respect to total abundance, generic composition and community trophic structure. On the two sampling dates (in spring and summer) significant more nematodes were found in the “tussocks” than “between tussocks”. Nematode communities were more diverse in the “tussocks” than “between the tussocks”, however the differences between two sites were significant only in spring. Each site had its own dominant genera different from the dominant genera of the adjacent site. Spatial pattern of nematodes was dynamic over time and seemed to be highly influenced by seasonal fluctuations of floods, which make the sites “between tussocks” available for nematodes only when floods recede.
9

Do physical-chemical water properties reflect the macrophyte and open water induced spatial heterogeneity of a shallow lake?

84%
Pelechaty M.
Oceanological and Hydrobiological Studies
|
2006
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tom 35
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nr 4
10

Relationship between groundwater depth and pattern of net primary production in oasis-desert ecotone

67%
Wu F.-J., Yu Z.-L., Wei X.-P., Deng J. M., Li T., Zhao C.-M., Wang G.-X.
Polish Journal of Ecology
|
2010
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tom 58
|
nr 4
Pattern of plant biomass and net primary production was investigated in two localities (Minqin and Linze) of oasis-desert ecotone (ODE) in Northwest China, in order to recognize the spatial and temporal variability of vegetation under same regional climate with different groundwater depth. The average depth to groundwater was over 14.02 m at Minqin -- marked further as DG (deep groundwater) and about 4.96 m at Linze -- marked further as SG (shallow groundwater). We have measured plant biomass and Netprimary productivity (NPP) across species, threetimes per year for three consecutive years, in sixplots along Minqin and Linze oasis-desert ecotone(further marked as DG and SG ODE), respectively.Our results showed that DG and SGODEs had different growth responses to differentgroundwater depths. DG ODE exhibited higherinter-annual variation in annual NPP (rangedfrom 0.18 to 9.30 g m⁻²) than did SG ODE (rangedfrom 0.42 to 17.99 g m⁻²). Decrease of groundwaterdepth had apparently altered the seasonalityof productivity in DG ODE systems, where precipitationin summer maintained plant growth,while ODE with high groundwater depth tendedto have higher spring NPP in SG ODE. Spatialand temporal heterogeneity of NPP at the scaleof our measurements was significantly greater inDG ODE than in SG ODE. SG ODE tended tosupport higher NPP than did DG ODE. In addition,the groundwater depth strongly influenced spatial and temporal heterogeneity of NPP in thedesert ecosystems. Clearly, the desert ecosystemwith higher groundwater depth is more stable andmore resistant to long-term drought or climateshifts in arid regions. These investigations andquantitatively analysis are very significant for theexecution of conservation and restoration in aridecosystems.
11

Stream habitats, benthic macroinvertebrates, lotic fish and their relationships: a multi-scale approach

67%
Fleituch T., Amirowicz A.
Polish Journal of Ecology
|
2005
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tom 53
|
nr 1
A natural reach of montane stream (length 96 m and 7 m width) was grided into 150 cells (2 × 2 m). Density and biomass of fish (Salmo trutta L. and Cottus poecilopus Heckel) were estimated at each cell, as well as stream depth, current velocity, Froude number, bed granulation and its roughness were measured, and benthic samples from exposed bricks were collected from mid August to early October. The analysis of spatial patterns of seven variables (five abiotic and two biotic ones) and fish occurrence from the period of highest organisms’ abundance confirmed that two fish species were separated within the stream space and sculpin showed close association to benthic prey. The PCA pointed to the highest loadings of abiotic habitat variables (64% of the total variance) indicating importance of hydraulics (stream velocity and Froude number) and bed characteristics (stream depth and bed roughness) in distribution of fish communities in pristine low order streams.
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