West Coast Of Canada Research Articles

Transgenic oilseed rape along transportation routes and port of Vancouver in western Canada

The occurrence of transgenic herbicide-resistant oilseed rape (Brassica napus) in ruderal (non-crop disturbed) areas has not been investigated previously in Canada. The primary objective of this study was to document their occurrence in two main ruderal areas (along railways and roads) in the province of Saskatchewan, where half of all oilseed rape is grown, and at the port of Vancouver, British Columbia on the west coast of Canada, where most oilseed rape destined for export is transported by rail. During the 2005 growing season, leaf samples of oilseed rape plants were collected at randomly-selected sites along railways and roads across Saskatchewan ecoregions and at Vancouver; infestation area, density, and plant height of oilseed rape were measured at each site. The presence of the glyphosate and glufosinate resistance traits was determined using test strips. The infestation area of oilseed rape, averaged across 155 sampled sites in the Saskatchewan survey, was markedly smaller in populations along railways than roads; in contrast, infestation area averaged across 54 sites in the Vancouver survey was greater for populations along railways than roads. In both surveys, mean plant density was greater for populations found along railways than roads. Two-thirds of oilseed rape plants sampled across Saskatchewan ecoregions and at Vancouver were transgenic, although the relative proportion of plants with the glyphosate or glufosinate resistance trait varied between surveys. Frequency of occurrence of transgenic plants in ruderal areas was similar to the proportion of the oilseed rape area planted with transgenic cultivars in the recent preceding years. A single transgenic B. rapa x B. napus hybrid was found along a road in Vancouver, confirming the relatively high probability of hybridization between these two Brassica species. With current control measures, transgenic oilseed rape populations may persist and spread in these ruderal areas.

COMPARISON OF THREE COMMON MOLECULAR TOOLS FOR DISTINGUISHING AMONG GEOGRAPHICALLY SEPARATED CLONES OF THE DIATOM SKELETONEMA MARINOI SARNO ET ZINGONE (BACILLARIOPHYCEAE)1

Skeletonema marinoi Sarno et Zingone is a planktonic marine diatom with a widespread geographic distribution. Different populations of this species may show distinct genetic signatures. We have evaluated the utility of three common molecular methods for distinguishing clones of S. marinoi from different geographic regions. Clonal cultures were isolated from the Canadian west coast, south west Portugal, and the east and west coasts of Sweden. All strains originated from resting stages in sediment. More than 90% of the individually isolated chains grew to densities suitable for DNA extraction. Genetic signatures of clones from each sample location were assessed by sequencing variable domains (D1–D3) of the nuclear large subunit (LSU) rRNA gene and internal transcriber spacer (ITS) (ITS‐1, 5.8S and ITS‐2) regions, and also by analysis of randomly amplified polymorphic DNA patterns. Analysis of molecular variance showed that strains from the four geographic areas were significantly separated by all three methods but that differences among European samples were best resolved by ITS 2 sequences.

Health of Chinese Illegal Immigrants Who Arrived by Boat on the West Coast of Canada in 1999

This was a retrospective review and descriptive analysis of the findings from the medical screening examinations conducted on the illegal migrants from Fujian Province of China (n = 589) who arrived on four boats on the West Coast of Canada between June 14 and September 9, 1999. The Canadian Navy conducted a screening medical exam of the illegal migrants, with Health Canada and Citizenship and Immigration Canada providing suggestions on the format of the exam. The illegal Chinese migrants were predominantly young, male adults. The most prevalent medical conditions detected were dermatological (55.2%), dental problems (25%), trauma (9.2%), urogenital (7.6%), and head/neck (6.6%). Recently induced trauma was more prevalent among females (20.5%) than males (6.5%). One case of community-acquired pneumonia was identified and later diagnosed as active pulmonary tuberculosis. Physicians dealing with illegal migrants should look for unusual physical findings and have a higher clinical suspicion regarding infectious diseases (tuberculosis, scabies) and abuse. Future encounters with illegal migrants should include standardized immigration screening exams, with adequate history taking and follow-up.

Seasonal foraging movements and migratory patterns of female Lamna ditropis tagged in Prince William Sound, Alaska

Conventional and electronic tags were used to investigate social segregation, distribution, movements and migrations of salmon sharks Lamna ditropis in Prince William Sound, Alaska. Sixteen salmon sharks were tagged with satellite transmitters and 246 with conventional tags following capture, and were then released in Prince William Sound during summer 1999 to 2001. Most salmon sharks sexed during the study were female (95%), suggesting a high degree of sexual segregation in the region. Salmon sharks congregated at adult Pacific salmon Oncorhynchus spp. migration routes and in bays near Pacific salmon spawning grounds in Prince William Sound during July and August. Adult Pacific salmon were the principal prey in 51 salmon shark stomachs collected during summer months in Prince William Sound, but the fish appeared to be opportunistic predators and consumed sablefish Anoplopoma fimbria, gadids, Pacific herring Clupea pallasi, rockfish Sebastes spp. and squid (Teuthoidea) even when adult Pacific salmon were locally abundant. As Pacific salmon migrations declined in late summer, the salmon sharks dispersed; some continued to forage in Prince William Sound and the Gulf of Alaska into autumn and winter months, while others rapidly moved south‐east thousands of kilometres toward the west coasts of Canada and the U.S. Three movement modes are proposed to explain the movement patterns observed in the Gulf of Alaska and eastern North Pacific Ocean: ‘focal foraging’ movements, ‘foraging dispersals’ and ‘direct migrations’. Patterns of salmon shark movement are possibly explained by spatio‐temporal changes in prey quality and density, an energetic trade‐off between prey availability and water temperature, intra‐specific competition for food and reproductive success. Transmissions from the electronic tags also provided data on depth and water temperatures experienced by the salmon sharks. The fish ranged from the surface to a depth of 668 m, encountered water temperatures from 4·0 to 16·8° C and generally spent the most time above 40 m depth and between 6 and 14° C (60 and 73%, respectively).

An Assessment of PCBs and OC Pesticides in Eggs of Double-crested (Phalacrocorax auritus) and Pelagic (P. pelagicus) Cormorants from the West Coast of Canada, 1970 to 2002

Eggs of double-crested and pelagic cormorants were collected between 1970 and 2002 from colonies in the Strait of Georgia, BC, Canada, and assayed for concentrations of organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs). Double-crested cormorant eggs from the early 1970's contained up to 4.1 mg kg-1 p,p'-DDE and 12.5 mg kg-1 sigmaPCBs. Corresponding values for pelagic cormorant eggs were 1.5 mg kg-1 p,p'-DDE and 3.9 mg kg-1 sigmaPCBs. Egg tissue concentrations of the dominant OC pesticides and sigmaPCBs dropped mainly during the 1970's, with minor declines thereafter. The data suggest that contaminant levels in cormorants have now stabilized at low levels throughout the resident population. Small but significant latitudinal gradients in several OC pesticides and PCBs indicated that areas of the southern strait were more contaminated than areas of the less populated northern strait. Interspecific differences in contamination may indicate that pelagic cormorants have a reduced capacity to metabolize chlordanes, DDT and PCBs compared to double-crested cormorants. Alternatively, the two species may have more divergent prey bases than previously thought. During the 1980's, TCDD toxic equivalents, largely contributed by polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), were correlated with physiological and biochemical alterations. Also, from 1989 to 1990, four deformed cormorant chicks (two of each species) were found during nest visits; none were found between 1991 and 1995. The relative rates of deformed chicks were 6 per 10,000 for double-crested and 16 per 10,000 for pelagic cormorants. The findings of deformed chicks were coincident with the period of highest PCDD and PCDF contamination; however, the sample sizes were too low to derive a substantive connection. Colony-wide productivity of double-crested cormorants was poorer in the southern colonies where PCBs in particular were elevated. While of concern, these lines of evidence are insufficient to conclude that chlorinated hydrocarbon contamination was a dominant contributor to population declines. It seems more probable that ecological variables, particularly changing prey and predator dynamics, drove the reductions in population size.

Modern to Late Holocene deposition in an anoxic fjord on the west coast of Canada: Implications for regional oceanography, climate and paleoseismic history

Laminated sediments preserved in the anoxic inner basin of Effingham Inlet on the Pacific coast of Vancouver Island, British Columbia, Canada, yield a high-resolution sediment deposition record spanning about 6000 yr. The varying thickness of diatom/terrigenous mud varves in sediment cores from the basin can be interpreted in terms of annual changes in surface productivity and freshwater input within the inlet. Similarly, the occurrence of unlaminated mud units (homogenites) intercalated amongst the laminated sediments can be interpreted in terms of oceanic and climatic changes. These units appear to be associated with coastal upwelling events that result infrequently in highly oxygenated oceanic water penetrating to the bottom of the inner and outer basins of the inlet. The sedimentary record also contains massive and graded mud units considered to arise from debris flows and turbidity currents, some of which were probably initiated by seismic events, including a major event about 4500 14C yr BP which may be earthquake related. A total of seventeen oceanographic surveys of the inlet beginning in 1995 characterize the modern seasonal coastal upwelling regime and a unique bottom water oxygenation event which was recorded in January 1999, following a rapid transition from the strong El Niño event of 1997–98 to the moderate La Niña event of 1998–99. Circum-Pacific evidence suggests that a “regime shift” from warm to cold conditions occurred in the central northeast Pacific in the late 1990s, indicating that the coastal ocean processes influencing Effingham Inlet sedimentation are likely modified by climate-scale ocean variability.

Reproduction and longevity of Aurelia labiata in Roscoe Bay, a small bay on the Pacific coast of Canada

Reproduction by the moon jelly, Aurelia labiata, was observed in a small bay on the west coast of Canada. The bay is located in an area isolated from human contact except in the summer, is sheltered from wind and wave action by mountain ridges, and has limited tidal flushing due to a gravel bar at the entrance that dries at lower low water. Planulae appeared in brood sacs beginning in October and November. The planulae were shed by the end of March and ephyrae emerged in June. Juvenile medusae were estimated to constitute about 30—40% of medusae in the bay in each of the two years of this study. Medusae remained in the bay throughout the year. There was no major visible mortality in the adult population during the two year observation period. Medusae appear to be lost from the bay as a result of tidal flushing. It is argued that in Roscoe Bay Aurelia labiata medusae live for more than one year and that up to 40% of the adult medusae may be two years of age or older.

Iron transport by mesoscale Haida eddies in the Gulf of Alaska

Abstract A two-year study of the iron distributions in anticyclonic mesoscale Haida eddies of the eastern North Pacific Ocean has shown that such eddies are a major source of iron to the high nitrate–low chlorophyll (HNLC) waters of the central Gulf of Alaska basin. These eddies, which are typically about 100 km in diameter, form off the west coast of Canada in winter and then track roughly westward into the open ocean. Therefore, they carry large quantities of iron-rich coastal waters into iron-limited waters of the oligotrophic gyre. When the eddies had first formed, their dissolved iron concentrations were nearly two orders of magnitude higher than is typically observed at Station Papa (50°N, 145°W; 3 n m versus less than 0.05 n m ), and the total iron in the eddies surface waters (10–40 m) was more than 13 n m higher than open ocean waters of the Alaska gyre (14 n m versus 0.5 n m ). While the overall iron content of the eddies decreased rapidly during the first year after they formed, the eddy we were able to track the longest still contained 1.5–2 times more iron than the surrounding waters 16 months after its formation. Therefore, although iron concentrations in the surface mixed layers of the eddies drop to levels observed outside very rapidly (within 4 months), upward transport along isopycnals and upwelling due to eddy decay, as well as vertical advective and diffusive transports typical of North Pacific waters, probably provide steady fluxes of iron into the euphotic zone from the still iron-rich eddy core waters throughout the lifetime of the eddy.

Issues in species classification of trees in old growth conifer stands

Old growth temperate conifer forest canopies are composed of assemblages of tree crowns that vary by species, height, size, and intercrown distance. The challenge this complexity presents to species classification is formidable. In this paper we describe the exploration of spectral properties of old growth tree crowns as captured on two independent acquisitions of 0.7 m ground resolution compact airborne spectrographic imager (CASI) airborne multispectral imagery. Underlying spectral separability is examined, and classifications of manually delineated crowns are compared against field-surveyed ground truth. Technical issues and solutions addressing individual tree species classification of old growth conifer stands are discussed. The study site is a western hemlock, amabilis fir, and red cedar dominated old growth area on Vancouver Island on the west coast of Canada. Within-species spectral variability is large because of illumination and view-angle conditions, openness of trees, natural variability, shadowing effects, and a range of crown health. As well, spectral differences between species are not large. An object-oriented illumination and view-angle correction was effective at reducing the effect of view angle on spectral variability. Radiometric normalization between imagery from flight lines of the same site and time period was successful, but normalization with data from other sites and days was not. The use of spectral samples from sunlit areas of the tree crowns (mean-lit signature) produced the best spectral separability and species classification. Because of the wide within-species variability and spectral overlap among species, it was also found useful to create internal subclasses within a species (e.g., normal and bright crowns). It was not feasible to consistently classify species of shaded crowns or stressed trees, and it was necessary to create overall shaded tree and unhealthy classes to prevent these trees from corrupting the final species classification. Classification results also depend on the visibility of trees in the imagery. This was demonstrated by different visibility and shade conditions of trees between the two image dates. This effect is particularly strong in old growth stands because of variations in stem density and spacing and the range of tree heights and sizes. Old growth stands will have shaded, unhealthy, and visually or spectrally unusual trees. Excluding these and considering species classification of manually delineated trees of the normal and bright spectral classes, modest success was achieved, in the order of 78% accuracy. Hemlock and balsam were confused, and cedar classification was mostly confused by the presence of unhealthy trees. If speciation of shaded and unhealthy trees was required, overall species classification was weak. It was shown, however, that shaded and unhealthy trees could be identified well using a classification with shaded and unhealthy classes. Species classification of the remaining trees, including the unusual trees, was 67% for the 1996 imagery and 77% for the 1998 imagery. Despite the difficulties in classifying species in an old growth environment, practical solutions to issues are available and viable spectral classifications are possible. Fully automated species isolation and classification add further complications, however, and new approaches beyond simple spectral techniques need to be explored.

Life Lived ‘like a map with all the rivers and hills showing’: Emily Carr’s travel vignette from the rough edge

This essay examines an autobiographical vignette by Canadian painter-writer Emily Carr (1871–1945) through the lens of Frye’s idea of the ‘explorer-painter’. Through wide-ranging research, the article touches on historical concepts of the Canadian West Coast, the role of the visual and of transportation structures in travellers’ experiences of landscape, the tension between the natural and industrial technological realms (particularly in regard to coastal salmon canneries), images of the body (racialised and/or aging and vulnerable), and Carr’s competing (self) representations. The centrepiece is the extraordinary, understudied ‘Salt Water’ story or vignette from Carr’s award-winning first book, Klee Wyck

Automated tree recognition in old growth conifer stands with high resolution digital imagery

Automated individual tree isolation and species determination with high resolution multispectral imagery is becoming a viable forest survey tool. Application to old growth conifer forests offer unique technical issues including high variability in tree size and dominance, strong tree shading and obscuration, and varying ages and states of health. The capabilities of individual tree analysis are examined with two acquisitions of 70-cm resolution CASI imagery over a hemlock, amabilis fir, and cedar dominated old growth site on the west coast of Canada. Trees were delineated using the valley following approach of the Individual Tree Crown (ITC) software suite, classified according to species (hemlock, amabilis fir, and cedar) using object-based spectral classification and tested on a tree-for-tree basis against data derived from ground plots. Tree-for-tree isolation and species classification accuracy assessment, although often sobering, is important for portraying the overall effectiveness of species composition mapping using single tree approaches. This accuracy considers not only how well each tree is classified, but how well each automated isolation represents a true tree and its species. Omissions and commissions need to be included in overall species accuracy assessment. A structure of rules for defining isolation accuracy is developed and used. An example is given of a new approach to accuracy analysis incorporating both isolation and classification results (automated tree recognition) and the issues this presents. The automated tree isolation performed well on those trees that could be visually identified on the imagery using ground measured stem maps (approximately 50–60% of trees had a good match between manual and automated delineations). There were few omissions. Commission errors, i.e., automated isolations not associated with a delineated ground reference tree, were a problem (25%) usually associated with spurious higher intensity areas within shaded regions, which get confused in the process of trying to isolate shaded trees. Difficulty in classifying species was caused by: variability of the spectral signatures of the old growth trees within the same species, tree health, and trees partly or fully shaded by other trees. To accommodate this variability, several signatures were used to represent each species including shaded trees. Species could not be determined for the shaded cases or for the unhealthy trees and therefore two combined classes, a shaded class and unhealthy class with all species included, were used for further analysis. Species classification accuracy of the trees for which there was a good automated isolation match was 72%, 60%, and 40% for the non-shaded healthy hemlock, balsam, and cedar trees for the 1996 data. Equivalent accuracy for the 1998 imagery was 59% for hemlock, 80% for balsam, with only a few cedar trees being well isolated. If all other matches were considered an error in classification, species classification was poor (approximately 45% for balsam and hemlock, 25% for cedar). However, species classification accuracies incorporating the good isolation matches and trees for which there was a match of an isolations and reference tree but the match was not considered good were moderate (60%, 57%, and 38% for hemlock, balsam, and cedar from the 1996 data; 62%, 61%, and 89%, respectively, for the 1998 imagery). Automated tree isolation and species classification of old growth forests is difficult, but nevertheless in this example useful results were obtained.

Oceanographic habitat of sponge reefs on the Western Canadian Continental Shelf

This paper describes oceanographic conditions in which siliceous (Hexactinellida, Hexactinosida) sponge reefs thrive near the heads of shelf canyons on the west coast of Canada. Unique in the present world ocean, these colonies consist of mounds (bioherms) up to 21 m in height and beds (biostromes), which extend for tens of kilometers at depths between 140 and 240 m. The relaxation of winter downwelling and occasional weak summer upwelling enhances northward up-canyon intrusions of nutrient rich bottom waters in Hecate Strait. As bottom waters cross the shelf, they are further enriched with nutrients and depleted in oxygen by remineralization processes. Silicate concentrations in waters around sponge reefs are thus enhanced during what is likely the sponge's main growing season. Bottom waters in the vicinity of the sponge reefs contain 43–75 μM silicate and 64–152 μM dissolved oxygen, and have a temperature range of 5.5–7.3 C and a salinity range of 33.2–34.2. Canyons harbouring the sponge reefs provide a means of concentrating particulate material that the sponges can use to enrich their habitat. Detrital rain supplies particulates to canyons in what appears to be tidally modulated pulses. Particulate material entrained in near bottom currents has a residence time of approximately 6 days in contact with the largest sponge reef and is effectively trapped by sponges, which enhances mound construction. A simple budget of Si uptake by the 425 km 2 area of the northern sponge reef shows that it has slight impact on the Si budget of this region. Scour by the ∼25 cm s −1 bottom tidal currents eliminates sediment accumulation on the reefs and the surrounding seabed.

Measured wind speed trends on the west coast of Canada

AbstractTrends in measured wind speed are discussed for four stations on the west coast of Canada. Periods of record vary with the station. They begin in the late 1940s or the 1950s and run through to the early to mid 1990s. The most prominent feature of the time series was a decline in mean annual and winter wind speeds at Cape St James, Victoria International Airport, and Vancouver International Airport during the middle portion of the record. Declines in mean annual wind speed are matched by increases in the percentage of calms and decreases in high wind speed observations. The pressure gradient between Victoria, Vancouver and Comox, the Pacific North American index, the Pacific decadal oscillation index, and other climate elements in British Columbia and the northwestern USA show trends at roughly the same time, indicating a natural cause of the wind speed decrease. Comox Airport mean wind speeds increased, however, perhaps the result of reduced friction in the vicinity of the anemometer outweighing the decrease in the regional pressure gradient. Copyright © 2004 Royal Meteorological Society

Sensitivity and uncertainty of the carbon balance of a Pacific Northwest Douglas-fir forest during an El Niño/La Niña cycle

The annual net ecosystem productivity ( F NEP) of a second-growth Douglas-fir stand established in 1949 on the Canadian West Coast varied considerably over the 4-year period between 1998 and 2001. This period included the El Niño/La Niña cycle during the northern hemispheric winters of 1997/1998 and 1998/1999, offering a unique opportunity to study how a typical forest ecosystem in the Pacific Northwest reacts to interannual climate variability. This was possible even though annual F NEP values calculated from eddy covariance (EC) measurements of CO 2 fluxes were subject to biases. These were largely due to the failure of the EC method to accurately measure losses of CO 2 under low turbulence conditions at night, which caused F NEP overestimates of as much as 90 g C m −2 per year. As these biases were largely unaffected by interannual climate variability, it was possible to reliably quantify interannual differences in F NEP estimates if they were larger than random variability, which was estimated to be ±30 g C m −2 per year at most. Interannual differences were mainly due to differences in ecosystem respiration ( R) between the 4 years. In the year following the 1997/1998 El Niño, high air temperatures led to the highest annual R of the 4 years, while annual gross ecosystem photosynthesis ( P) was only slightly higher than normal. This resulted in 1998 having the lowest F NEP (270 g C m −2 per year) of the 4 years. For 1999, a cool and cloudy La Niña year, F NEP was 360 g C m −2 per year, much higher than 1998, but somewhat lower than the last 2 years, for which F NEP values were 390 and 420 g C m −2 per year, respectively.

Altimeter observations of sea-level variability off the west coast of North America

A combination of careful harmonic analysis and high-resolution numerical modelling of tides in altimeter data from TOPEX/Poseidon and ERS-2 satellites allows detailed calculation of seasonal and interannual variability of sea level in coastal areas of the north-east Pacific Ocean. These calculations show large changes in sea level in marginal seas during the 1997–8 El Niño and La Niña events, as well as providing information on the origin and life cycle of large anticyclonic eddies, observed to be generated off the west coast of Canada.

SeaWiFS global composite images show significant features of Canadian waters for 1997–2001

The sea-viewing wide field-of-view sensor (SeaWiFS) is designed to image the spectral water-leaving radiance in ocean and coastal waters with timing and spatial resolution suitable for a range of marine and coastal environmental monitoring. The monthly composite time series compiled by the National Aeronautics and Space Administration (NASA) provides a valuable data source that deserves to be more widely known and applied in regional studies. This paper presents examples of time series of Canadian coastal waters compiled for each month from September 1997 to December 2001 for the west coast of Canada (British Columbia), the Great Lakes, and the east coast of Canada (Gulf of St. Lawrence and Newfoundland – Grand Banks). The time series show the seasonal and interannual variations of phytoplankton surface concentration and the occurrence of major bright plankton blooms on the B.C. coast, in the Gulf of St. Lawrence, and on the Grand Banks. In addition, "bright-water" events are shown in Lake Erie and Lake Michigan. Many cases also occur where the reflectance of large areas of water is increased by sediment from rivers or resuspended bottom sediment. The data show the value of a consistent time series of satellite data, both for single-band radiance products and for the derived chlorophyll data. In particular, the water brightness data show significant events that do not appear to have been reported in the scientific literature.

Proposed System for Hydrogen Production from Methane Hydrate with Sequestering of Carbon Dioxide Hydrate

Methane hydrate exists in huge amounts in certain locations, in sea sediments and the geological structures below them, at low temperature and high pressure. Production methods are in development to produce the methane to a floating platform. There it can be reformed to produce hydrogen and carbon dioxide, in an endothermic process. Some of the methane can be burned to provide heat energy to develop all needed power on the platform and to support the reforming process. After separation, the hydrogen is the valuable and transportable product. All carbon dioxide produced on the platform can be separated from other gases and then sequestered in the sea as carbon dioxide hydrate. In this way, hydrogen is made available without the release of carbon dioxide to the atmosphere, and the hydrogen could be an enabling step toward a world hydrogen economy.

Valuing freshwater salmon habitat on the west coast of Canada

Changes in land use can potentially reduce the quality of fish habitat and affect the economic value of commercial and sport fisheries that rely on the affected stocks. Parks and protected areas that restrict land-use activities provide benefits, such as ecosystem services, in addition to recreation and preservation of wildlife. Placing values on these other benefits of protected areas poses a major challenge for land-use planning. In this paper, we present a framework for valuing benefits for fisheries from protecting areas from degradation, using the example of the Strait of Georgia coho salmon fishery in southern British Columbia, Canada. Our study improves upon previous methods used to value fish habitat in two major respects. First, we use a bioeconomic model of the coho fishery to derive estimates of value that are consistent with economic theory. Second, we estimate the value of changing the quality of fish habitat by using empirical analyses to link fish population dynamics with indices of land use in surrounding watersheds. In our example, we estimated that the value of protecting habitat ecosystem services is C$0.93 to C$2.63 per ha of drainage basin or about C$1322 to C$7010 per km of salmon stream length (C$1.00=US$0.71). Sensitivity analyses suggest that these values are relatively robust to different assumptions, and if anything, are likely to be minimum estimates. Thus, when comparing alternative uses of land, managers should consider ecosystem services from maintaining habitat for productive fish populations along with other benefits of protected areas.

Combined high-density lidar and multispectral imagery for individual tree crown analysis

Lidar technology has reached a point where ground and forest canopy elevation models can be produced at high spatial resolution. Individual tree crown isolation and classification methods are developing rapidly for multispectral imagery. Analysis of multispectral imagery, however, does not readily provide tree height information and lidar data alone cannot provide species and health attributes. The combination of lidar and multispectral data at the individual tree level may provide a very useful forest inventory tool. A valley following approach to individual tree isolation was applied to both high resolution digital frame camera imagery and a canopy height model (CHM) created from high-density lidar data over a test site of even aged (55 years old) Douglas-fir plots of varying densities (300, 500, and 725 stems/ha) on the west coast of Canada. Tree height was determined from the laser data within the automated crown delineations. Automated tree isolations of the multispectral imagery achieved 80%‐90% good correspondence with the ground reference tree delineations based on ground data. However, for the more open plot there were serious commission errors (false trees isolated) mostly related to sunlit ground vegetation. These were successfully reduced by applying a height filter to the isolations based on the lidar data. Isolations from the lidar data produced good isolations with few commission errors but poorer crown outline delineations especially for the densest plot. There is a complimentarity in the two data sources that will help in tree isolation. Heights of the automated isolations were consistently underestimated versus ground reference trees with an average error of 1.3 m. Further work is needed to test and develop tools and capabilities, but there is an effective synergy of the two high resolution data sources for providing needed forest inventory information.

Concentrations of dimethyl sulfide in the Strait of Georgia and its impact on the atmospheric sulfur budget of the Canadian West Coast

A study was conducted in the Strait of Georgia to determine the seasonal variation of the biogenic sulfur budget, mainly dimethyl sulfide (DMS), during the three seasons, autumn (November 1999), spring (April 2000) and summer (August 2000). During autumn, surface DMS concentrations were low, 0.02–0.3 nmol l−1. They were highest during spring, 2–30 nmol l−1 and moderately high during summer, 0.2–14 nmol l−1. Related parameters such as chlorophyll a (chl a) and particulate or dissolved dimethyl sulphonioproprionate (DMSPp and DMSPd) were also measured. DMSPp levels were highest during spring coincident with the highest chl a concentrations. In contrast, DMSPd concentrations were highest during summer. Using the Liss‐Merlivat model for sea‐air gas exchange DMS fluxes to the atmosphere was calculated. The areal average DMS flux from the Strait of Georgia decreased from a maximum of 6.4 μmol m−2 d−1 during the spring to 2.2 μmol m−2 d−1 during the summer to 0.15 μmol m−2 d−1 during the autumn. DMS emissions from the Georgia Basin can contribute as much as 26% to the total sulfur emissions (natural and anthropogenic) from the region. Our results also indicate that biogenic sulfur emissions from the Pacific Ocean are also an important source of sulfur to the total regional sulfur budget for the Lower Fraser Valley and they will become more important as anthropogenic S emissions become better controlled.