Ograniczanie wyników

Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 35

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  Ireland
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
Bank voles Clethrionomys glareolus Schreber, 1780 were first discovered in Ireland in 1964. They are confined to the south-west and, judging by their rate of spread, are a recent introduction. Mitochondrial DNA was extracted from 81 bank voles from 5 localities. Only 2 haplotypes were observed, indicating that the founder population was small. There were marked differences in the relative frequencies of haplotypes between sites. These are most readily explained by local founder effects brought about by the habitat preference of this rodent and sustained by the territorial behaviour of females.
The diet of Daubenton's bat Myotis daubentonii (Kuhl, 1817), which takes prey by aerial hawking and from the surface of water, was investigated by analysis of faeces collected in summer at 7 roosts, all close to rivers in pastoral land, in three widely­-separated districts in Ireland. Forty-seven categories of arthropod prey were identified; several were insect taxa found in and around water. Most categories were recovered at most roosts, but mainly in small amounts. The main categories were the same through­out, accounting for 82% of the diet by percentage frequency in droppings for pooled data: Chironomidae/Ceratopogonidae 24% (adults 14%, preadult stages 10%), other nematoceran Diptera 21%, other Diptera 10%, and Trichoptera 26% (adults 20%, preadult 6%). A quarter of the prey had evidently been obtained from the water's surface (eg aquatic insects, their larvae and pupae). Although consumption of several food items varied significantly by month at one or more roosts, little of such variation was consistent between roosts.
The diet of the Irish hare Lepus timidus hibernicus Bell, 1837, was investigated in western Ireland by analysis of faeces collected each month for a year from 3 areas of blanket bog, 1 of rough grassland and 1 of machair. A wide range of plant species was eaten but the main foods throughout the year were grasses and sedges on bog, and grasses at the other 2 sites, with sedges a minor food. Forbs were also important on machair, the study area where they were most plentiful. Shrubs (mainly Calluna vulgaris but Thymus praecox on machair) were an ancillary food everywhere, especially in winter, when they provided an otherwise scarce source of live tissue, Because there was no snow cover, however, shrubs did not dominate forage in winter as they do in other parts of the range of L. timidus. Seasonal variation in the diet and apparent food preferences are discussed.
A new record of the chondrichthyan hybodontoid genus Lissodus is presented from two localities within the Mississippian (Tournaisian) rocks of Ireland. Five morphotypes of the genus are described within each of which occurs morphological variance. Specimens recovered and described herein are from crinoidal limestones whose palaeoenvironments are interpreted as ranging from a moderately shallow high−energy carbonate shelf, to relatively deep off−shore. The richest fauna recovered from the high−energy carbonate shelf, contains all five morphotypes raising the possibility that they may have been derived from a single species of shark. A discussion on the relationship between the five morphotypes and other Carboniferous Lissodus teeth is offered and it is argued that although the morphotypes differ slightly from other Carboniferous Lissodus teeth, they may belong to a closely related species not formally named until additional evidence is obtained. A mouth reconstruction using the teeth recovered from the Lower Carboniferous of Ireland is proposed.
The presence of riparian vegetation is shown to affect both physical and biological properties of headwater streams. Riparian vegetation mediates food resource availability for macroinvertebrates and fish within streams through addition of allochthonous material such as leaves, woody debris and terrestrial invertebrates. Riparian shade can also reduce biomass and production of autochthonous algae. The potential role of riparian vegetation in enhancing biodiversity and productivity of headwater streams is discussed, with reference to improving salmonid fish stocks in the headwater streams of Ireland and Great Britain.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 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.