Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 3

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 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 / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
In highly seasonal temperate zones climate may cause fluctuations in the accessibility of prey for insectivorous bats. The main objective of this project was to evaluate if these fluctuations can result in resource bottlenecks that affect the body condition of a temperate zone bat — Myotis myotis. Seasonal changes in body condition followed different patterns in Portugal and Germany, which have different climates. In Germany bats use thermally better hibernacula, which allow them to minimize energy expenditure, but because of the longer winters they emerge from hibernation in poorer condition. Except during the hibernation period, food was always abundant in Germany, but the condition of the animals was poor when bad weather constrained foraging, particularly in early spring. In Portugal food was limiting during the long dry summer, and this affected the condition of the animals for several months. The conclusion that food resources can act as a limiting factor is relevant for conservation because, like other bat species, M. myotis forages mostly in agricultural and forestry habitats, and can be affected by practices that accentuate resource bottlenecks. Where necessary, the management of agroecosystems near colonies of M. myotis and of other threatened bats should aim at minimizing seasonal food bottlenecks.
We reviewed published and unpublished written reports on bat mortality at wind farms in northwestern Europe. The estimated number of bats killed per turbine annually was relatively low (0–3) on flat, open farmland away from the coast, higher (2–5) in more complex agricultural landscapes, and highest (5–20) at the coast and on forested hills and ridges. The species killed almost exclusively (98%) belonged to a group (Nyctalus, Pipistrellus, Vespertilio and Eptesicus spp.) adapted for open-air foraging. The bats were killed by the moving rotor blades as they hunted insects attracted to the turbines. This occurred independently of sex and age. Peak mortality varied considerably in frequency and timing among years, but the events usually (90%) occurred on nights with low wind speeds in late July to early October and to a lesser extent (10%) also in April-June. The mortality increased with turbine tower height and rotor diameter but was independent of the distance from the ground to the lowest rotor point. It was also independent of the size of the wind park (1–18 turbines). Bat species other than the open-air suite referred to above are usually not at risk at wind turbines, because they fly below the rotors, but are still killed occasionally (2%).
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 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.