Systematic aerial line-transect surveys of beluga whales, Delphinapterus leucas, were conducted in James Bay, eastern Hudson Bay, and Ungava Bay from 14 August to 3 September 2001. An estimated 7901 (SE = 1744) and 1155 (SE = 507) belugas were present at the surface in the offshore areas of James Bay and Hudson Bay, respectively. An additional 39 animals were observed in estuaries during the co...

Underwater visual census (UVC) is the most common approach for estimating diversity, abundance and size of reef fishes in shallow and clear waters. Abundance estimation through UVC is particularly problematic in species occurring at low densities and/or highly aggregated because of their high variability at both spatial and temporal scales. The statistical power of experiments involving UVC tec...

Nacrtak Assessment of disturbance can provide forest managers with information to make appropriate decisions on site rehabilitation and monitoring. This paper evaluates the accuracy of successive estimates of site disturbance using two ground survey methods. The results from the point transect and grid point transect and grid point intercept methods were compared with the results from an intens...

The effects of the colonization of an abandoned grassland by forest trees and the associated microenvironmental changes on soil properties and the microbial activity of soil were studied along a 170 m transect established on a former pasture colonized by Norway spruce (Picea abies Karst.) in Central Slovakia. The transect with a 5×5 m grid of sampling points crosses all successional stages from...

The responses of pine forest to changing climate and environmental chemistry were studied along two transects following the pollution and continentality gradients in Poland. One axis begins on the western border of Poland, crosses the country along the 52nd parallel, and ends on the eastern border of Poland in the area of Bialowieza National Park, Biosphere Reserve. The second axis begins in in...

We conducted at-sea line transect surveys for Marbled Murrelets (Brachyramphus marmoratus) to determine density off the coast of central California and to explore the utility of various survey protocols. Surveys were designed to compare line versus strip transect methods, and reveal the effects of distance from shore, viewing conditions and seasonal trends on density estimates. On consecutive d...

The isotopic composition of tree-ring cellulose was obtained over a two-year period from small diameter, riparian zone trees along an elevational transect in Big Cottonwood Canyon, Utah, USA to test for a possible temperature dependence of net biological fractionation during cellulose synthesis. The isotope ratios of stream water varied by only 3.6% and 0.2% in deltaD and delta18O, respectively...

[1] Nitrogen isotopes provide integrated information about nitrogen cycling in terrestrial ecosystems. This study explores the regional patterns of ecosystem N abundance along a 1200 km transect in Inner Mongolian grasslands and their relationships with climate. Results indicate that climatic variables control approximately 50% of the variation in ecosystem N abundance along the transect. Ecosy...