Southern Vancouver Island Research Articles

Tracing the influence of sewage discharge on coastal bays of Southern Vancouver Island (BC, Canada) using sedimentary records of phytoplankton

The impact of sewage and stormwater effluents on phytoplankton is investigated by comparing organic-walled dinoflagellate cyst abundance and diversity from 38 surface sediment samples, flanking southern Vancouver Island. Site locations include those directly adjacent to wastewater outfall at Clover and Macaulay Points and Saanich Peninsula, as well as from a variety of near-shore environments with differing tidal flow influences. Excellently preserved dinoflagellate cyst assemblages have been recovered and 36 cyst taxa were identified. Local assemblages are characterized by a high relative proportion (average 56%) of cysts produced by heterotrophic dinoflagellates, which is typical for regions of high primary production. Relative proportional increases of cysts from heterotrophic species with particular increases of Polykrikos kofoidii/schwartzii and Dubridinium species, known to reflect areas affected by eutrophication, occur directly adjacent to all three sewage outfalls, as well as in the more stagnant waters of Esquimalt and Victoria Harbours and at the mouth of Cadboro Bay. Further effects of an anthropogenic effluent can be seen in the relatively higher concentrations of organic carbon and the diatom production proxy, biogenic opal. Results from this study clearly indicate a much larger impact zone than predicted by a sewage effluent plume model or trends found in monitored benthic biota and sediment chemistry that evidence primary outfall affects <800 m eastward of Macaulay Point and about 200 m eastward of the Clover Point. Enhanced production of cysts from potentially toxic Alexandrium species is also observed near locations of sewage outfalls.

Tidal modulation of slow slip in Cascadia

Several studies have shown that the seismic tremor in episodic tremor and slip is tidally modulated, suggesting a sensitivity to the rather small tidal stresses. We address whether the slip rate in slow slip events is also tidally modulated by examining data from six borehole strainmeters in northwest Washington and southern Vancouver Island. We simultaneously fit data from multiple stations and from slow slip events occurring over a 3 year interval from January 2007 to June 2009, as we are unable to extract a meaningful signal from a single record. We find modulation of the strain rate with a 12.4 h period, that of the tide with the largest amplitude, that is significant at the 99% level. The amplitude of this modulation suggests that the slip rate during slow slip events oscillates, on average, 25% above and below its mean value during a tidal cycle. Tidal modulation estimates at three other periods are significant with more than 70% probability. The phase of maximum strain rate in the 12.4 h M2 period coincides with the phase of the maximum tremor rate taken from a catalog in an overlapping region. Comparison with a simple tidal loading model shows that the phase of maximum strain rate in the M2 period may occur at the maximum shear stress or up to 90° before it, depending on the location of slip in the subduction zone.

Giant short-faced bear (Arctodus simus) from late Wisconsinan deposits at Cowichan Head, Vancouver Island, British Columbia

A giant short-faced bear ( Arctodus simus ) ulna fragment was found at the base of exposed Quaternary sediments at Cowichan Head, southern Vancouver Island, British Columbia. In this paper, the ulna fragment and its geological context are described and a reasonable taphonomic trajectory is presented. The radiocarbon age of 22 750 ± 140 BP on the bone indicates that these bears were on Vancouver Island during the late Wisconsinan. A likely source for the Cowichan Head A. simus was from the mainland to the southeast.

Generation and evolution of a topographically linked, mesoscale eddy under steady and variable wind-forcing

Numerical simulations with the Regional Ocean Modeling System (ROMS) are used to study the initial spin-up and the evolution of a mesoscale, topographically linked eddy under steady and variable wind conditions. The development of a pool of dense water on the southern Vancouver Island shelf allows cyclonic eddies formed by coastal upwelling off Cape Flattery to spread westward, ultimately contributing to the shelf-wide circulation known as the Juan de Fuca Eddy. This dense water arises through upwelling of water present in the underlying canyon system and tidal mixing over several shallow banks to the north. Tidal mixing is critical to the separation of the eddy from the coast. Although steady upwelling winds with a seasonal mean magnitude (combined with estuarine flow and tides) produce an eddy, only fluctuating winds with timescales and magnitudes typical of the region result in an eddy with a westward extent similar to seasonal observations. With each period of upwelling-favorable winds, newly upwelled water from the coast is entrained into the eddy which grows in size and moves westward. Wind events also significantly affect the baroclinic structure of the eddy. Specifically, during typical summer wind reversals, model surface drifters continue to move cyclonically within the eddy for several days after each downwelling wind event. Under upwelling-favorable wind conditions, model drifters exit the eddy to the southeast as the eddy and coastal upwelling fronts merge into a continuous southeastward shelf break jet.

Summer Feeding Habits of River Otters Inhabiting a Contaminated Coastal Marine Environment

Abstract In two recent studies, North American river otters (Lontra canadensis) inhabiting the urbanized/industrialized harbors of southern Vancouver Island, British Columbia, Canada were found to be exposed to elevated levels of environmental contaminants, primarily industry-produced polychlorinated biphenyls (PCBs). Contaminant exposure in those studies was assessed non-invasively, by measuring chemical residue concentrations in river otter feces collected from established marking sites (latrines). As river otter exposure to contaminants is primarily through their diet, our aim was to characterize river otter prey selection from feces collected at latrine sites inside the contaminated harbors and along the relatively uncontaminated coastline outside the harbor systems. Fish occurred in 95.5% of all feces analyzed, with species of gunnels (Pholidae), sculpins (Cottidae), pricklebacks (Stichaeidae), toadfish (Batrachoididae), clingfish (Gobiesocidae), flatfish (Pleuronectiformes), and snailfish (Liparidae...

Fecal genotyping and contaminant analyses reveal variation in individual river otter exposure to localized persistent contaminants

The present study investigated polyhalogenated aromatic hydrocarbon (PHAH) concentrations in feces of known river otters (Lontra canadensis) along the coast of southern Vancouver Island, British Columbia, Canada. Specifically, we combined microsatellite genotyping of DNA from feces for individual identification with fecal contaminant analyses to evaluate exposure of 23 wild otters to organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenylethers (PBDEs). Overall, feces collected from otters in urban/industrial Victoria Harbor had the greatest concentrations of nearly all compounds assessed. Fecal concentrations of OCPs and PBDEs were generally low throughout the region, whereas PCBs dominated in all locations. Re-sampling of known otters over space and time revealed that PCB exposure varied with movement and landscape use. Otters with the highest fecal PCB concentrations were those inhabiting the inner reaches of Victoria Harbor and adjacent Esquimalt Harbor, and those venturing into the harbor systems. Over 50% of samples collected from eight known otters in Victoria Harbor had total-PCB concentrations above the maximum allowable concentration as established for Eurasian otter (Lutra lutra) feces, with a geometric mean value (10.6 mg/kg lipid wt) that exceeded the reproductive toxicity threshold (9 mg/kg lipid wt). Those results are consistent with our findings from 1998 and 2004, and indicate that the harbors of southern Vancouver Island, particularly Victoria Harbor, are a chronic source of PCB exposure for otters. The present study further demonstrates the suitability of using otter feces as a noninvasive/destructive biomonitoring tool in contaminant studies, particularly when sampling of the same individuals at the local population-level is desired.

Northern Cascadia episodic tremor and slip: A decade of tremor observations from 1997 to 2007

We analyze continuous seismic and GPS records collected in the last decade (1997–2007) to establish the most comprehensive observational basis for northern Cascadia episodic tremor and slip (ETS) events. A simple “ETS scale” system, using a combination of a letter and a digit, is proposed to quantitatively characterize the spatial and temporal dimensions of ETS events. Clear correlation between GPS and tremor signals is observed for all A/B class episodes, but the GPS signature is less obvious for minor ones. Regular ETS recurrence can be established only for A/B class episodes in southern Vancouver Island. Halting and jumping are very common in ETS migration patterns, and along‐strike migration can happen in both directions. A prominent tremor gap is observed in midisland around 49.5°N. This gap coincides with the epicenters of the only two large earthquakes beneath Vancouver Island. ETS tremors also tend to occur in places where the local seismicity is relatively sparse. The tremor depth distribution shows a peak in the 25–35 km range where strong seismic reflectors (i.e., the E layer) are documented. Detailed waveform analysis confirms the existence of shallow tremors above the currently interpreted plate interface. Our results suggest that a significant portion of the tremor activity and perhaps associated shearing are taking place along well‐developed structures such as the E layer, while fewer tremor bursts are generated elsewhere in response to the induced stress variation throughout the source volume.

Modelling physico-chemical factors affecting occurrences of a non-indigenous planktonic copepod in northeast Pacific estuaries

Estuarine ecosystems along the Pacific coast of North America are vulnerable to invasions by non-indigenous planktonic copepods, with documented invasions by at least nine species introduced via ship’s ballast. One of these, the calanoid copepod Pseudodiaptomus inopinus, now occurs in a relatively wide geographical area in coastal estuaries of Washington and Oregon States. Although it appears to be well established in the region, plankton surveys conducted in 1992, 1996, 2000, and 2004 in estuaries from southern Vancouver Island in British Columbia, Canada, to northern California, United States indicate that it has not expanded its range. This static distribution suggests that P. inopinus has reached a distributional limit, and it may thus be a good organism for applying models for predicting planktonic invasions, by characterizing estuaries with and without populations of the copepod. In this study, we applied both parametric, linear (discriminant function analysis, logistic regression) and nonparametric, non-linear (classification trees) techniques to develop models for occurrence of P. inopinus, to identify parameters that may lead to successful invasions and to identify specific estuaries or regions that might be at risk of invasion by this species. Both model types had similar results, identifying relatively simple salinity- and stratification-based models as good predictors of P. inopinus. While different models selected slightly different sets of variables and thresholds, all models identified relatively low salinity and stratification of water column temperature and salinity as important predictors of P. inopinus presence. The models also identified several “false positives” that mainly occurred in more inland waters of Puget Sound—estuaries that did not have P. inopinus, but had the conditions that support it, and which may be at risk for future invasions by this species.

Thermal and metamorphic environment of subduction zone episodic tremor and slip

Episodic tremor and slip (ETS) have been detected in the Cascadia and southwest Japan subduction zones, where the subducting crust is relatively warm because of the young incoming lithosphere (&lt;20 Ma) and modest plate convergence rates (∼40–60 mm/a). In the southwest Japan subduction zone, low‐frequency earthquakes occur on the plate interface at depths of 30–35 km beneath Shikoku where finite element thermal models predict temperatures of ∼425°C in the subducting oceanic crust and at depths of 30–40 km beneath the Kii Peninsula where predicted temperatures are ∼325°C. Warmer temperatures of ∼575°C are predicted at ETS depths beneath southern Vancouver Island in the Cascadia subduction zone, but here tremor also occurs within the overlying fore‐arc crust where temperatures are lower. In the southwest Japan and Cascadia subduction zones, subducting oceanic crust passes through the blueschist, greenschist, and amphibolite metamorphic facies where mineral dehydration reactions are complex. The different temperatures predicted for the two subduction zones suggest that ETS does not coincide with a specific temperature or metamorphic reaction. Several lines of evidence indicate that a free H2O‐rich fluid is present, at least transiently, in subducting oceanic crust and fluids released by prograde metamorphic dehydration reactions may help trigger or enable ETS within the subducting plate. Less clear is the role H2O may play in tremor observed in the Cascadia fore‐arc crust where free H2O may exist locally in faults and fractures, but retrograde hydration reactions are expected to consume H2O.

Current and future trends in juvenile wood density for coastal Douglas-fir

Increment cores from 10 full-sib families in each of three planting series were collected on 22 test sites per series (a total of 7063 samples across 63 sites). Juvenile wood density for individual test sites ranged from 0.378 to 0.481. Stepwise multiple linear regression analysis with wood density as the dependent variable and a battery of annual and monthly climate variables as independent variables was used to model the current distribution of wood density across the landscape in coastal British Columbia. Differences in the average temperature between the coldest month and the warmest month, precipitation in July, and the mean annual precipitation were the only significant variables predicting wood density, accounting for 47% of the total variation across all sites. Using two future climate change models (CGCM2 A2x and HADCM3 A2x) to predict changes in the three climate variables, wood density was mapped. Wood density will be reduced generally in the present range of coastal Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii ), especially on southern Vancouver Island and along the coastlines of southern British Columbia. This may have implications for the future utility of Douglas-fir as a structural wood species, as well as for breeding and deployment.

Sea-level change and paleogeographic reconstructions, southern Vancouver Island, British Columbia, Canada

Forty-eight new and previously published radiocarbon ages constrain deglacial and postglacial sea levels on southern Vancouver Island, British Columbia. Sea level fell rapidly from its high stand of about +75 m elevation just before 14 000 cal BP (12 000 radiocarbon yrs BP) to below the present shoreline by 13 200 cal BP (11 400 radiocarbon years BP). The sea fell below its present level 1000 years later in the central Strait of Georgia and 2000 years later in the northern Strait of Georgia, reflecting regional differences in ice sheet retreat and downwasting. Direct observations only constrain the low stand to be below −11 m and above −40 m. Analysis of the crustal isostatic depression with equations utilizing exponential decay functions appropriate to the Cascadia subduction zone, however, places the low stand at −30 ± 5 m at about 11 200 cal BP (9800 BP). The inferred low stand for southern Vancouver Island, when compared to the sea-level curve previously derived for the central Strait of Georgia to the northwest, generates differential isostatic depression that is consistent with the expected crustal response between the two regions. Morphologic and sub-bottom features previously interpreted to indicate a low stand of −50 to −65 m are re-evaluated and found to be consistent with a low stand of −30 ± 5 m. Submarine banks in eastern Juan de Fuca Strait were emergent at the time of the low stand, but marine passages persisted between southern Vancouver Island and the mainland. The crustal uplift presently occurring in response to the Late Pleistocene collapse of the southwestern sector of the Cordilleran Ice Sheet amounts to about 0.1 mm/yr. The small glacial isostatic adjustment rate is a consequence of low-viscosity mantle in this tectonically active region.

NEW CRETACEOUS AND EOCENE DECAPODA (ASTACIDEA, THALASSINIDEA, BRACHYURA) FROM BRITISH COLUMBIA, CANADA

Abstract A collection of Cretaceous and Eocene specimens of decapod crustaceans from southern Vancouver Island, British Columbia, Canada, has yielded the following new taxa: Cowichianassa meckerti, new genus, new species (Callianassidae); Comoxianassa haggarti, new genus, new species (Callianassidae); Preclarocarcinus parvus, new genus, new species (Homolodromiidae); and Nitotacarcinus canadensis, new species (Tumidocarcinidae). Two of the new taxa are callianassid ghost shrimp, each of which displays sexual dimorphism and is well documented from major and minor claws as well as abdomina, unusual in the fossil record and especially unusual for Cretaceous forms. Nitotacarcinus was known previously only from the Eocene of Denmark; thus, the new species extends its paleobiogeographic range dramatically. The layers in which the decapods were collected from the Paleogene Via Appia Beds were deposited in generally high-energy conditions favoring the formation of glauconite. Cuticular structures of Eucorystes pl...

Patterns of within and between-colony microsatellite variation in the endangered Vancouver Island marmot (Marmota vancouverensis): implications for conservation

Among the 14 extant species of the genus Marmota the Vancouver Island marmot (Marmota vancouverensis) is the most endangered. In 2007 as few as 85 individuals were left in the wild, with an additional 162 individuals maintained in captivity. To facilitate genetic monitoring of both wild and captive populations, polymorphic genetic markers were identified. Thirty-three different microsatellite loci were tested for amplification and variability in ≥30 wild-born individuals. Only 11 of these loci proved to be polymorphic and were subsequently analysed in 105 samples collected from wild Vancouver Island marmots. The average number of alleles (A) at those 11 loci was only 2.1, and the intraspecific variation (HE between 8 and 23% within colonies) was low compared to other marmot species. Variation within the small and geographically isolated Mt. Washington colony was particularly low (A = 1.3, HE = 0.08). Genetic distances between the Mt. Washington colony (11 individuals) and those of the Nanaimo Lakes region (94 individuals) on southern Vancouver Island were large (D values ranging from 0.42 to 0.50), while genetic distances among colonies within the latter area were much smaller (D values from 0.01 to 0.13). Given the low within-population genetic variation, and the resulting risk of inbreeding depression at Mt. Washington, we support the decision to maximize overall genetic variation of the species by crossbreeding marmots from the two different areas despite the possibility of local adaptation.

Complexity in modelling forest ecosystems: How much is enough?

The levels-of-integration concept in ecology suggests that while the population and community levels of biological organization provide understanding, they do not provide an adequate basis for predicting future states of populations, communities or ecosystems. Empirical models of populations and communities are implicitly ecosystem level because they are based on measures of the results of all past determinants that affected the populations and communities in question. They can be good predictors under unchanging conditions, but they are not able to predict for changing conditions, which requires the explicit representation of those ecological processes that are anticipated to change. The question addressed in this paper is: how does the performance of a “simple” stand-level model change as representations of these processes are added, and how much complexity is enough? Examples are given of change in performance of the ecosystem management model FORECAST run as a light competition model as nutrient regulation of growth and understory interactions are added singly or in combination. These examples are framed in comparisons of simulations for a white spruce stand in the in boreal mixedwood region in northern British Columbia, for a long-term thinning-fertilization trial in a Douglas-fir stand on southern Vancouver Island, and for yield decline in Chinese fir in south eastern China. It is concluded that the effect of adding complexity on the predictions of this model depends on the time scale of the simulation and the management or natural disturbance regime that is being simulated. The results supported Occam's razor: that models should be as simple as possible but as complex as necessary.

Paleomagnetism and counterclockwise tectonic rotation of the Upper Oligocene Sooke Formation, southern Vancouver Island, British Columbia

The age of the Sooke Formation on the southern coast of Vancouver Island, British Columbia, Canada, has long been controversial. Prior paleomagnetic studies have produced a puzzling counterclockwise tectonic rotation on the underlying Eocene volcanic basement rocks, and no conclusive results on the Sooke Formation itself. We took 21 samples in four sites in the fossiliferous portion of the Sooke Formation west of Sooke Bay from the mouth of Muir Creek to the mouth of Sandcut Creek. After both alternating field (AF) and thermal demagnetization, the Sooke Formation produces a single-component remanence, held largely in magnetite, which is entirely reversed and rotated counterclockwise by 35° ± 12°. This is consistent with earlier results and shows that the rotation is real and not due to tectonic tilting, since the Sooke Formation in this region has almost no dip. This rotational signature is also consistent with counterclockwise rotations obtained from the northeast tip of the Olympic Peninsula in the Port Townsend volcanics and the Eocene–Oligocene sediments of the Quimper Peninsula. The reversed magnetozone of the Sooke sections sampled is best correlated with Chron C6Cr (24.1–24.8 Ma) or latest Oligocene in age, based on the most recent work on the Liracassis apta Zone molluscan fauna, and also a number of unique marine mammals found in the same reversed magnetozone in Washington and Oregon.

Estimating nitrogen exports in response to forest vegetation, age and soil types in two coastal-forested watersheds in British Columbia

This study compared the variability in nitrogen (N) export as a function of (i) vegetation types, (ii) soil types, and (iii) both vegetation and soil types using the least square estimation method for two coastal-forested watersheds in southern Vancouver Island, British Columbia, Canada. Nitrogen exports estimated using both vegetation and soil types were found to be more accurate than those estimated by either vegetation or soil types alone. Results showed that forested wetlands had the highest N exports ranging from 0.16 to 0.98 kg ha −1 year −1 for ammonium-N (NH 4-N), from 0.27 to 2.95 kg ha −1 year −1 for nitrate-N (NO 3-N) and from 3.48 to 5.61 kg ha −1 year −1 for total N (TN). Young forests had the lowest N exports ranging from 0.03 to 0.74 kg ha −1 year −1 for NH 4-N, from 0.01 to 0.21 kg ha −1 year −1 for NO 3-N and from 0.57 to 1.03 kg ha −1 year −1 for TN. Duric Dystric Brunisols had the highest N exports, 2.78 kg ha −1 year −1of TN and Orthic Ferro-Humic Podzols had the lowest, 1.54 kg ha −1 year −1 of TN. A Hoerl curve described the response of N export rates to the change of forest ages well. Average TN export decreased from 4.00 kg ha −1 year −1 for forest regeneration to 0.75 kg ha −1 year −1 for young forests and then increased from 1.28 kg ha −1 year −1 for mature forests to 1.74 kg ha −1 year −1 for old-growth forests. Using watershed protection, as an example, that will eventually convert all the current forests into old-growth forests, an even area distribution of forest ages from regeneration to mature will reduce N export from forested lands to streams by up to 37% in Sooke Lake watershed.

A 90-year sea warming trend explains outbreak patterns of western spruce budworm on Vancouver Island

Three outbreaks of western spruce budworm were recorded on southern Vancouver Island between 1909 and 1930. After 1930, outbreaks were restricted to interior regions of British Columbia. We show that warming winter temperatures on southern Vancouver Island, related to warming sea temperature, promoted earlier larval emergence while the timing of bud flush has remained constant. This differential response to changed climate has resulted in a significant departure from optimal phenological synchronization that would explain the outbreak history. Key words: climate change, phenology, bud flush, Douglas-fir

Castilleja victoriae (Orobanchaceae): a New Rare Species from Southeastern Vancouver Island, British Columbia, Canada, and the Adjacent San Juan Islands, Washington, U.S.A

ABSTRACT Castilleja victoriae is described from the vicinity of southwestern Victoria, southern Vancouver Island, British Columbia, Canada and from San Juan Co., Washington, U.S.A. It is an annual member of subg. Colacus (Jeps.) T.I. Chuang & Heckard, sect. Oncorhynchus (Lehm.) T.I. Chuang & Heckard, formerly placed in the genus Orthocarpus Nutt. It is apparently most closely related to either Castilleja ambigua Hook. & Arn. or Castilleja tenuis (A. Heller) T.I. Chuang & Heckard. The new species differs primarily in its uniformly dull reddish-brown floral bracts and calyces, bicolored and unspotted corollas, and restrictive habitat requirements. Several historic populations are extirpated, and of the three extant populations only one consists of enough individuals in a protected location to be considered reasonably secure. We advocate additional surveys of its limited habitat and conservation measures to protect the species.

Markets for Western Canada's Forest Products in East Asia

Introduction While the United States has long been the most important destination for western Canada's forest products, markets in Asia have also played an important role in the development of western Canada's forest industry. Japan has been an especially significant market, although demand for western Canada's exports in Japan has fallen in recent years. Western Canada's reliance on U.S. demand has increased as a result, and a strong economy and a widespread construction boom in the United States have provided a further pull toward this market. However, U.S. demand has recently weakened, creating risks to the sustainability of an industry that plays a critical role in western Canada's economy. At the same time, the economic landscape in Asia is shifting, creating both opportunities and threats for western Canada's forest sector. This article will discuss several topics related to the role of East Asia's markets in western Canada's forest industry. First, the history of western Canada's forest industry and export trends will be reviewed. The current state of forest product markets in Asia will then be examined. Some specific trends that may affect future demand for forest products in Asia will be identified, and overall economic trends in some key markets will be summarized. Examples of initiatives to improve Canada's forest product trade with Asia will be outlined. Finally, advantages that western Canada's forest product exporters have and some of the challenges they face in the region will be discussed. The Early Development of Western Canada's Forest Industry The first recorded export of forest products from western Canada took place in 1788, when a ship set sail from Vancouver Island's Nootka Sound carrying planks and spars to be sold in China (Mackay 1982). While the value of western Canada's forests was recognized by early explorers and settlers, shipments such as this were incidental through the late 18th and early 19th centuries, and most timber was harvested for local use. Indeed, western Canada's Aboriginal people have harvested timber and other forest products for local use for thousands of years. Aboriginal communities historically used timber for constructing houses, canoes, totem poles, and boxes, and made items such as baskets, hats, mats, rope, and clothing from yellow and red cedar. They also used timber and other vegetation for fuel, food, medicines, and a variety of other domestic uses (Turner and Cocksedge 2001). However, by the early 1860s, some of the newly arriving settlers on Canada's west coast had established sawmills on southern Vancouver Island and the mainland (around what is now the City of Vancouver), and shipments to a variety of destinations in the Pacific Rim began to occur. Lumber and spars were shipped to markets in the United States, Mexico, Hawaii, China, Australia, Peru, and Chile (Lawrence 1957). Beams made of prime British Columbia timber were shipped to China for use in the Imperial Palace in Beijing (Mackay 1982). The early industry struggled: many sawmills operated for only a year or two before going out of business or changing hands. The arrival of the Canadian Pacific Railroad in 1886 swept the industry out of its pioneer stage and into growth and change (Mackay 1982, 16). The timber needs of the railroad itself were a source of demand, and once in operation, the railroad provided a ready means for transporting products outside the region. The railroad also helped financial and human capital flow into western Canada, facilitating the region's economic growth (Lawrence 1957). However, the arrival of the railroad also shifted the focus of western Canada's forest industry toward supplying markets in the east, especially in the rapidly growing prairie region, rather than overseas. By the end of the First World War, markets in the east had declined, and lumber manufacturers on Canada's west coast once again looked across the Pacific for opportunities. …

Recovery of nontarget Lepidoptera on Vancouver Island, Canada: One and four years after a gypsy moth eradication program

The gypsy moth (Lymantria dispar) is a destructive defoliator that is not established in British Columbia, Canada, because of successful eradication programs involving the microbial insecticide Bacillus thuringiensis var. kurstaki (Btk). In 1999, three aerial applications of Btk were made over two areas, totaling 12,805 ha, on southern Vancouver Island, Canada. The impacts of these Btk applications on nontarget Lepidoptera were studied from 1999 to 2004 on Garry oak (Quercus garryana) and common snowberry (Symphoricarpos albus). In 1999, lepidopteran larvae were collected from S. albus foliage at 24 urban parks and from Q. garryana foliage at 28 oak-dominated habitats. The initial impacts (i.e., 1999 data) were published previously, and the present paper is a continuation of the same study. We tested two hypotheses: Reductions of nontarget Lepidoptera would be more severe at 12 to 13 months postspray than at one to two months postspray, and recovery would be significant, though not necessarily complete, at four years postspray. The total number of nontarget Lepidoptera on S. albus and Q. garryana was significantly reduced in the treatment sites in each year of the study: the reduction was greatest in 2000. Relative to the reference sites, each of 11 species that were initially reduced by the Btk applications showed an increase in the treatment sites between 2000 and 2003, by which time only four species remained significantly reduced in the treatment sites. The uncommon species were significantly reduced in 1999 and 2000 but not in 2003, indicating that some recovery had occurred. Limitations and economic implications of the present study are discussed.