Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 52

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 3 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 3 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
The current problem in farmland ecology is the change in the character of rural development in areas neighbouring cities and towns. Progressive urbanization and the prediminance of housing estates over agricultural aims led to a change in the bird community. During 2005– 2010, a survey of birds wintering within densely populated built-up rural areas was conducted by the line transect method (a total length of 8 km). A total number of 33 species was recorded and the most numerous dominant was the House Sparrow Passer domesticus, which constituted 32–58% of the bird community. The group of dominants and subdominants (which constituted up to 20% of the bird community) included the Yellowhammer Emberiza citrinella and the Rook Corvus frugilegus, and a group of forest and synanthropic species – the Great Tit Parus major, the Blue Tit Cyanistes caeruleus, the Blackbird Turdus merula, and the Collared Dove Streptopelia decaocto. The total density varied in subsequent study years from 57.4 to 87.5 ind. 10 ha–1 and was approximately twice lower than in other rural regions studied in Poland. A significant decrease in the wintering birds’ diversity index was recorded through the study period. The explanations for this could be in the character of villages in the proximity of builtup city areas. This has rapidly changed in recent years, and nowadays agricultural management in the region is discarded. As a result, farmlands of the region almost entirely lost their agricultural character, notably becoming a residential and recreational backup for cities. The villages neighbouring cities and towns are developed into suburban- like areas, where housing estates predominate over agricultural aims. Future consequences of these changes are far-reaching for farmland biodiversity and ecology. The decrease in species diversity and evolution into urban-like bird communities is the most probable scenario.
W dniu 2 maja 2012 roku, w Wisłoce koło miejscowości Myscowa (Beskid Niski) odnaleziono stanowisko ściśle chronionego gatunku ryby – różanki Rhodeus sericeus. Odnotowano kilkanaście osobników w ubarwieniu godowym zasiedlających niewielkie starorzecze oddzielone od głównego nurtu rzeki kamienistą łachą częściowo porośniętą roślinnością. Jest to obecnie jedyne w Polsce stanowisko tego gatunku w granicach alpejskiego regionu biogeograficznego
Kulon
|
2007
|
tom 12
103-104
Kulon
|
2003
|
tom 08
|
nr 2
51-52
W dniu 9 września 2013 roku w Ustrzykach Dolnych (Góry Sanocko-Turczańskie) odnotowano nowe stwierdzenie węża Eskulapa Zamenis longissimus. Martwego osobnika znaleziono na drodze biegnącej w pobliżu niewielkiego cieku wodnego płynącego na obrzeżach miasta. Całkowita długość ciała odnalezionego osobnika wynosiła 168 cm. Niniejsze stanowisko jest aktualnie najdalej na północ wysuniętym w Polsce. Wąż Eskulapa jest gatunkiem krytycznie zagrożonym wyginięciem w kraju. Śmiertelność osobników dorosłych zabijanych przez pojazdy jest jednym z podstawowych zagrożeń, którego eliminacja powinna być zadaniem priorytetowym.
A study of wintering Common Crossbills (Loxia curvirostra L.) was conducted in the winter periods 2002/2003–2006/2007 in the Western Carpathians. Birds were surveyed on transects in natural mountain European beech (Fagus sylvatica L.)-Silver fir (Abies alba Mill.)- Norway spruce (Picea abies (L.) Karst.) forests of the Tatra Mts, Pieniny Mts, Babia Góra Mt. and Gorce Mts (total length 41.4 km) as well as in a habitat mosaic with Scots pine (Pinus sylvestris L.) and Mountain pine (Pinus mugo Mill.) stands in the Kotlina Orawsko-Nowotarska valley (total length 31.5 km). Birds mean density underwent annual changes from 1.9 to 15.5 ind. 10 km⁻¹ in the natural mountain forests and from 0.9 to 12.1 ind. 10 km⁻¹ in the habitat mosaic. The median flock size in the natural mountain forests was 2, and it varied from 1 to 4 in subsequent seasons. They were smaller than flocks recorded in the habitat mosaic in the valley – median 2.5 (from 2 to 7 in subsequent seasons). The size of foraging and flying flocks did not differ significantly in natural mountain forest nor in the valley habitat mosaic. In the natural mountain forests, birds preferred habitats dominated by Norway spruce, and avoided European beech-Silver fir forests. The median flock size was 2 in habitats with Norway spruce, and 8 in stands where Norway spruce was absent. The variation in bird density presumably reflected the changes in quantity and location of food resources. Birds moved within stands with varying proportions of Norway spruce in the mountains as well as between the mountains and the valley, where habitat with mosaics of Scots pine and Mountain pine dominated.
Larval galleries and exit holes of adult insects in wood and bark are a conspicuous indication of the occurrence of many species. Therefore it allows the qualitative and quantitative examination of insect populations. However, evaluation of adult body size based on the size and shape of galleries and exit holes was not practiced. We analyzed relationship between selected biometric traits (pronotal width, elytral width, and length of elytron) of adult Rosalia alpina (L.) − an endangered representative of the longhorn beetles (Cerambycidae) − and the size and shape of their exit holes. Based on the laboratory reared individuals, we evaluate the size and shape of exit hole of each adult. Adult biometric traits were strongly correlated with each other. No sexual differences were found in adult beetle size and exit hole size and shape. The size of exit holes was, however, a good indicator of adult body size. The correlation between exit hole size and the size of adult R. alpina was highly significant for all studied traits, whereas exit hole shape was weakly correlated with adult size. The results of this study show new possibilities for applying the size of adult exit holes to study and wider characterize populations of R. alpina, which includes e.g. inter-population, inter-habitat, or inter-host material comparisons and determination of adult body size changes over time-period.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 3 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.