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Kosmos
Astronomia Astrofizyka
Inne

Kultura
Sztuka dawna i współczesna, muzea i kolekcje

Metoda
Metodologia nauk, Matematyka, Filozofia, Miary i wagi, Pomiary

Materia
Substancje, reakcje, energia
Fizyka, chemia i inżynieria materiałowa

Człowiek
Antropologia kulturowa Socjologia Psychologia Zdrowie i medycyna

Wizje
Przewidywania Kosmologia Religie Ideologia Polityka

Ziemia
Geologia, geofizyka, geochemia, środowisko przyrodnicze

Życie
Biologia, biologia molekularna i genetyka

Cyberprzestrzeń
Technologia cyberprzestrzeni, cyberkultura, media i komunikacja

Działalność
Wiadomości | Gospodarka, biznes, zarządzanie, ekonomia

Technologie
Budownictwo, energetyka, transport, wytwarzanie, technologie informacyjne

BC Journal of Ecosystems and Management

Previous work in Alaska indicates that the distribution of Arctic grayling (Thymallus arcticus) along streams is influenced by fish size. Larger fish are usually found in the upstream reaches, and the meansize gradually decreases further downstream, closer to the stream mouth. One of the hypotheses supporting this observation is that larger fish have a feeding advantage because they have first accessto drifting prey. This mechanism is also believed to occur within pools. This extension note provides further evidence supporting the size gradient of Arctic grayling in streams. I use data from two riversin northern British Columbia and one river in Alberta to show similar patterns of size distribution.

http://jem.forrex.org/index.php/jem/article/view/19 2011/02/17 - 15:59

I examined wildlife tree, coarse woody debris, and windthrow characteristics of 157 retention patches left in harvested areas of the Kispiox (mostly ICHmc), and Bulkley/Morice (mostly SBSmc, ESSFwv/mc) Timber Supply Areas in the early to mid 1990s. Patches added substantially to important habitat elements in the harvested areas. Windthrow rates were moderate, totalling about 11% and 19% of the post-harvesting standing tree basal area (after 12-16 years post-harvest) in the Kispiox and Bulkley/Morice samples respectively. Most of the windthrow occurred in the first few years post-harvest, and then dropped to background levels. I conclude that, overall, windthrow is not a significant issue. If, however, minimizing windthrow is a goal then previous rule-of-thumb criteria still apply: create larger patches (>1 ha) of minimum perimeter, oriented to minimize perimeter exposure to prevailing winds and place patches on topographically sheltered sites.

http://jem.forrex.org/index.php/jem/article/view/18 2011/02/17 - 15:59