Surface Water Accumulation Research Articles

Use of Agricultural Lands by Waterfowl in Southwestern British Columbia

The distribution, abundance, and food habits of overwintering pintails (Anas acuta), mallards (A. platyrhynchos), and American wigeon (A. americana) in agricultural lands in a portion of the lower Fraser Valley, British Columbia, were investigated in response to proposals to improve land drainage and flood protection. Numbers of birds in fields were strongly influenced by numbers along an adjacent estuary and by the amount of standing surface water in the fields. Pintails and wigeon preferred pastures to other land-use types, and wigeon generally avoided hay, cereal, or vegetable crop fields. Mallards showed no measurable preferences among types of land use. Pintails made extensive use of weed, grass, and sedge seeds and invertebrates in pastures, and also fed on decaying potatoes. Wigeon were predominantly grazers of green leafy and uprooted vegetation. Mallards were generally nonselective in their food habits in the fields. Waterfowl appeared to use agricultural lands on an opportunistic basis, as an extension of traditional coastal winter habitats. J. WILDL. MANAGE. 45(2):454-462 The Fraser River Delta and associated tidal foreshores along the eastern side of the Straits of Georgia, British Columbia, provide important winter habitat for Pacific Flyway waterfowl (Bellrose 1976). Leach (1972) identified Boundary Bay, Mud Bay, Roberts and Sturgeon banks, the Fraser River islands, marshes of the Pitt River (tributary to the Fraser), and the Fraser Valley farmlands as key components of available habitat. From 40,000 to 50,000 dabbling ducks are estimated to occur in Boundary and Mud bays and along Sturgeon and Roberts banks from mid-November through December (Vermeer and Levings 1977). Maximum numbers at the height of the southward migration are estimated at 100,000-200,000. Numbers decline in January, but approximately 10,000-15,000 dabblers typically remain through the winter along the tidal foreshores (Vermeer and Levings 1977). Waterfowl numbers in the area during the summer are low, and are limited to suitable breeding habitat within small refuges. Farmlands adjacent to Boundary and Mud bays are used extensively by pintails, mallards, and wigeon throughout the winter. A key factor in the use of farmlands appears to be the high incidence of surface-water accumulation resulting from heavy winter rainfall, high groundwater levels, and occasional flooding from coastal creeks and rivers. This study to quantify waterfowl use of farmlands was undertaken in response to proposals to improve farmland drainage and protection from flooding. Funding for the study was provided by a grant to the British Columbia Fish and Wildlife Branch under the Agricultural Rehabilitation and Development Act. B. J. Clark provided assistance with fieldwork. J. P. L. Savard and D. M. Skead reviewed the manuscript. 1 Present address: Environmental and Socio-economic Services Department, British Columbia Hydro and Power Authority, 555 West Hastings Street, Vancouver, B.C. V6B 4T6, Canada. 2 Present address: Range Division, British Columbia Forest Service, 540 Borland Street, Williams Lake, B.C. V2G 1R8, Canada. 454 J. Wildl. Manage. 45(2):1981 This content downloaded from 157.55.39.248 on Thu, 28 Jul 2016 06:14:37 UTC All use subject to http://about.jstor.org/terms WATERFOWL USE OF LANDS IN BRITISH COLUMBIA* Hirst and Easthope 455

Salar de Surire un ecosistema altoandino en peligro, frente a escenario del cambio climático

Este trabajo realiza un análisis al salar de Surire desde el punto de vista de la biodiversidad y sus implicancias producto del cambio climático. Como resultado se predice que los próximos años serán secos y la temperatura podría ir en aumento, lo cual afectará notablemente a la flora y fauna del altiplano. El salar de Surire es un cuerpo salino ubicado en el altiplano andino chileno, en un entorno geológico de características volcánicas. La climatología actual de aridez no permite una acumulación de agua superficial de gran extensión, y por lo tanto es posible diferenciar tres tipos principales de aguas: los aportes de drenaje, las acumulaciones de agua en la aureola pantanosa externa o “bofedales”, y las aguas del interior del cuerpo salino (surgencias termales y salmueras). Estas condiciones hidrológicas afectan factores abióticos, como anaerobiosis de suelos, disposición de nutrientes y salinidad, factores determinantes del desarrollo de la flora y fauna. Palabras claves: Salar de Surire; Biodiversidad andina; Cambio climático; Ecosistema andino DOI: http://dx.doi.org/10.5377/nexo.v24i1.593 Nexo, Vol. 24, No. 1, pp. 43-49, 2011

A Review of the Temperature and Salinity Structures in the Approaches to Vancouver Island, British Columbia

Oceanographic data gathered along the west coast of Vancouver Island since 1933 have been examined in an effort to derive an appreciation of oceanographic processes in this region.One area, which was the source of most data, was chosen as representative for the study, principally to satisfy continuity and partly to offset the tendency to use isolated sets of data as examples of "typical" coastal structure under rather general circumstances.The temperature and salinity structures and distributions are revealed as basically being functions of fresh water input, insolation, wind, and the ocean influence. The local climate is outlined, and some pertinent physical processes are reviewed, prior to a generalized description of the coastal oceanographic system.Predominant northwest winds and local runoff result in a shallow (20 to 40 m) springtime halocline in coastal waters. Summer insolation and the resulting stability of the thermocline, coincident with the halocline, limit the depth of mixing so that the summer runoff from mainland sources is mainly preserved in the shallow (10 to 20 m) upper zone of the salinity structure.Intermittent wind-induced divergence and an entrainment demand is offered as reason for the occurrence of cold, saline bottom water in this region during the summer.Autumnal cooling and southeasterly winds destroy the vertical structures and result in a near-shore accumulation of dilute surface water in winter. Relatively warm bottom temperatures offer evidence of a winter convergence, or relaxation of the divergence mechanism.Coastal oceanographic structures are often dominated by short-term variabilities. The significance of these is demonstrated by the ranges of variation obtained during time-series observations.

Does the Bulk of Ocean Water increase?

THE idea was, I think, suggested by myself, and has been referred to with approval by Mr. Jukes-Browne, that much of the water on the surface of the globe was originally occluded in the molten interior, and has been emitted by volcanic action in the course of ages. Mr. Mellard Reade argues against this, that the moon is covered with volcanic craters, and yet has no water on its surface, and that if the accumulation of surface water has followed volcanic action on the earth, it ought likewise to have done so on the moon. He concludes:—“At all events, it seems a reasonable question to ask why oceans should be supplied with water from the perspiring pores of mother earth, while her offspring, the moon, is so dry as to have absorbed into herself all evidence of any aqueous envelope that may have formerly existed.”