Traffic volume and highway permeability for a mammalian community in the Canadian Rocky Mountains

We examined whether highway traffic volume changed the rates of movement (habitat permeability) for ten mammalian species in the central Canadian Rocky Mountains. Winter track count data were collected on four highways of varying traffic volume: the Trans-Canada Highway (TCH) (14,000 annual average daily traffic [AADT]) and 1A Highway (3,000 AADT) in Banff National Park and the Highway 40 (5,000 AADT) and Smith Dorrien Trail in Kananaskis Country (2,000 AADT). Permeability represented the ratio of road crossing tracks/km to tracks/km on transects adjacent to roads. We compared permeability at the community level and for carnivore and ungulate guilds, using a Kruskal–Wallis H -test. Traffic volume significantly reduced habitat permeability for the community ( P  < 0.05). Pair-wise Kruskal–Wallis tests showed that habitat permeability was significantly reduced for carnivores at high traffic volume ( P  = 0.008) and for ungulates at very high traffic volume ( P  < 0.043). Cross-referencing with winter traffic counts, we found movement was impaired for carnivores when traffic ranged from 300 to 500 vehicles per day (VPD) and for ungulates between 500 and 5,000 VPD. Our results indicated that the TCH requires mitigation to restore habitat permeability for all species and yielded strong evidence that the Highway 40 is a priority for mitigation.     

A Late Holocene vertebrate food web from southern Haida Gwaii (Queen Charlotte Islands, British Columbia)

This study presents isotopic data (δ¹³C and δ¹⁵N from bone collagen) for 104 samples representing 29 vertebrate taxa from late pre-contact through to contact era (ca. 2000 – 100 BP) Haida Gwaii (British Columbia, Canada) from a wide variety of mostly marine organisms. The results demonstrate the considerable isotopic variability that characterizes potential prey items in coastal contexts and underscores the need for baseline faunal data to interpret human subsistence practices. Based on these data, a detailed marine food web was constructed, which provides insight into local ecological conditions. We present a simple method for quantifying the trophic level of ancient fauna using δ¹⁵N of bone collagen. Finally, we discuss the implications of this study for the reconstruction of human diet.     

Emwadea microcarpa gen. et sp. nov.—anatomically preserved araucarian seed cones from the Winton Formation (late Albian), western Queensland,Australia

Dettmann, M.E., Clifford, H.T., Peters, M., June 2012. Emwadea microcarpa gen. et sp. nov.—anatomically preserved araucarian seed cones from the Winton Formation (late Albian), western Queensland, Australia. Alcheringa, 217–237. ISSN 0311-5518.

A new genus and species, Emwadea microcarpa Dettmann, Clifford & Peters, is established for ovulate/seed cones with helically arranged cone scales bearing a centrally positioned, inverted ovule from the basal Winton Formation (late Albian), Eromanga Basin, Queensland. The cones are small, prolate ellipsoidal (9.5–14 mm vertical axis, 6.3–8.7 mm transverse axis) with wedge-shaped cone scales bearing winged seeds attached adaxially to the scale only by tissues surrounding the vasculature entering the ovule. Ovuliferous tissue that is free from the cone scale extends distally from the chalaza; the seeds' lateral wings are derived from the integument. Foliage attached to the cones is spirally arranged, imbricate and with spreading and incurved bifacial blades with acute tips; stomata are arranged in longitudinal files and are confined to the adaxial surface. The cone organization testifies to placement within the Araucariaceae, and is morphologically more similar to Wollemia and Agathis than to Araucaria.

Mary Dettmann [mary.dettmann@qm.qld.gov.au] and Trevor Clifford, Queensland Museum, PO Box 3300, South Brisbane, Q 4101, Australia; Mark Peters, PO Box 366 Gumeracha, SA 5233, Australia. Received 31.3.2011; revised 23.8.2011; accepted 5.9.2011.