Ograniczanie wyników

Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 103

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 6 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  zmiany florystyczne
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 6 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
3
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Ocena zmian florystycznych runi trawnikow miejskich.

88%
The experiments on the street lawns were conducted in the years 1986 and 1996-1997. The aim of the experiments was to investigate the changes in the composition of the street lawns sward during the 10 years by estimating the floral composition and the share of living as well as synantrophic forms. The number of plant species in the sward increased from 77% in 1986 to 91% ten years later. Within the same period of time the grass share in the sward cover composition decreased from 59% to 24%. The group of dicotyledonous species was the dominating one. The share of taxons increased considerably within both the leguminous plants group (from 3 to 14 species) as well as the cover composition (from 3,5% to 17%). During the ten years in question the share of lawn plants (of Molinio-Arrhenatheretea) decreased, whilst that of synanthropic plants increased. Among the sward cover composing plants the native species, that is apophytes, dominated. However their share in the sward cover decreased from 96% to 82% during the period under investigation. Both the synantrophic plants as well as the living forms share in the lawn sward influenced the sustainability of lawns. The negative influence is that of the considerable share of the one-year species. During the ten years their share in the sward cover composition increased from 8% in 1986 to 33% in 1996-97. The changes in the lawns composition during the ten-year period influenced the sustainability of lawns. They were positive on one hand - the sward cover increased due to the increased number of taxons. On the other hand they were negative as the share of the ruderal species and that of intruder species increased.
Aura
|
1998
|
nr 07
18-19
Meadows and pastures occupy some 4 million hectares in Poland and constitute 21 per cent of arable land. Since they are man managed or made, their vegetation is most at risk. In recent decades, the meadow and peat-bog vegetation have decreased as a direct result of environmental contamination and degradation. The disappearing of flora has numerous implications. It leads to further relentless upsetting of the environmental balance. A loss of any species means decreased stability of the whole ecosystem as it disturbs the whole network of environmental interconnections.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 6 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.