Wyniki wyszukiwania

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Gravel pits as habitat islands: floristic diversity and vegetation analysis

100%

Bzdon G.

Polish Journal of Ecology

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2008

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tom 56

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nr 2

239-250

Open-cut excavations formed as a result of exploitation of mineral deposits are the least studied ecological sites. Habitat heterogenity is reflected by remarkable floristic and phytocoenotic diversity. Being isolated by the surrounding vegetation of contrasting types – they can be considered as “habitat islands”. Twenty excavations (area from 100 m² to 2 ha) were selected – 10 located in cropland, 10 – in coniferous forest. The intensiveness of gravel pit exploitation was differentiated. Some of them were exploited, other ones were abandoned 10–30 years ago. The floristic records were taken during summer period in each pit and in near-by vegetation at the distance not larger than 200 m. As much as 280 species of vascular plants were found in 10 selected gravel pits surrounded by coniferous forest communities, which contained only 111 taxa. The flora of mid-field excavations was definitely richer that the flora of their surroundings. Sörensen’s similarity index (So ) for mid-forest gravel pits and their surroundings ranged between 27% and 40% while that for midfield gravel pits and their neighbourhood – from 15% to over 27%. The U Mann-Whitney test demonstrated that the number of species noted in selected gravel pits significantly differed from that in the surrounding. It was true for both (mid-forest Z = 3.70; P = 0.00021) and mid-field gravel pits (Z = 3.78; P = 0.00016). Native species were dominating in the flora of both mid-field and mid-forest excavations (77% and 82 % respectively). Hemicryptophytes were found to dominate (46%) over other groups of life forms in both types of gravel pits. A high contribution of terophytes – over 19% in mid-forest excavations and over 25% in mid-field ones is noteworthy. The results showed that gravel pits could play a role of enclaves for natural and semi-natural vegetation thus acting as local centres of floristic diversity in human modified monotonous agricultural or monospecies pine forest landscape.

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Abandoned cropland as a habitat of the Whinchat Saxicola rubetra in SW Poland

100%

Orlowski G.

Acta Ornithologica

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2004

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tom 39

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nr 1

The study was carried out on 94 abandoned arable fields (0.1-83.5 ha) comprising a total area of 400 ha in the intensively farmed region of the Wrocław plain (54.8 km², SW Poland). A total of 101 Whinchat territories were found in the study area, all of them in abandoned crop fields with a well-developed layer of dried perennials from the previous year (Tanacetum vulgare, Artemisia vulgaris, Solidago sp.). Whinchats occupied 56 (60%) of the 94 fields surveyed. The probability of a Whinchat occupying a particular field was closely related to its size: the probability of occupation was 50% in fields of about 1.8 ha, and rose to 100% in fields larger than 13 ha. Single males occupied thirty-eight territories (37.6%). The number of Whinchat territories per occupied abandoned field lay between 1 and 14. Thirty-three fields held only a single Whinchat territory. The density of Whinchat territories was negatively correlated with the size of an abandoned field. Single males inhabited the smallest fields.

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Breeding bird communities in relation to different habitat islands

80%

Tworek S.

Nature Conservation

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2001

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tom 58

Ograniczanie wyników

1 Acta Ornithologica

1 Nature Conservation

1 Polish Journal of Ecology

1 Bzdon G.

1 Orlowski G.

1 Tworek S.

1 2008

1 2004

1 2001

Gravel pits as habitat islands: floristic diversity and vegetation analysis

Abandoned cropland as a habitat of the Whinchat Saxicola rubetra in SW Poland

Breeding bird communities in relation to different habitat islands