Quercus Garryana Research Articles

Physiological Response of Garry Oak (Quercus garryana) Seedlings to Drought

The purpose of this study was to determine physiological differences in drought response among Garry oak (Quercus garryana Douglas ex Hook. [Fagaceae]) seedlings from acorns collected at seven acorn collection sites in Washington state. Our objective was to aid in Garry oak restoration efforts by investigating potential differences in drought tolerance for seedlings grown from acorns collected at different sites. Acorns were collected from six sites east of the Cascades, and one site on Whidbey Island (Oak Harbor) west of the Cascades. Differences in morphological and photosynthetic characteristics observed for seedlings grown from acorns collected at these different sites became more pronounced after drought stress was induced by withholding water. Seedlings from acorns collected at the northernmost east-side site (Swauk Creek) were most susceptible to drought and had photosynthetic rates that were 35% lower under drought conditions than when well-watered. Seedlings from acorns collected at the site west of the cascades (Oak Harbor) were the least susceptible to drought and had assimilation rates under drought conditions that were similar to those when well-watered. Differences were also observed among seedlings from different sites in the occurrence of drought-induced loss of stem hydraulic conductivity and changes in leaf water potential and relative water content in response to drought. We conclude that seedlings grown from Garry oak trees at different sites across Washington State have distinct physiological responses to drought that may lead to differing survivorship when used in reforestation efforts and exposed to drought stress in the field.

A Multi-Proxy Environmental Narrative of Oregon White Oak (Quercus garryana) Habitat in the Willamette Valley, Oregon

Oregon white oak (Quercus garryana) habitat is a priority for conservation in the Pacific Northwest, with process-oriented management considered fundamental for the restoration of these ecosystems. Given that natural and anthropogenic processes operate across a wide spatial and temporal range, an historical perspective provides a more holistic understanding of the complex dynamics of these systems. To this end, we employed a multi-proxy approach to develop an environmental narrative of the Willamette University at Zena Forest (WUZ), Willamette Valley, Oregon between AD 1800 and 2014. We used historic written records, aerial photographs, ecological community characteristics, climate data, and dendrochronological data to investigate forest patterns and processes at the plot, stand, site, and regional scales. Our results illustrate temporal shifts in the importance of factors, including land use and ecological succession, in driving landscape change and forest development at WUZ. Critically, this narrative indicates that modern, patchwork vegetation patterns at WUZ are largely a consequence of anthropogenic practices that became increasingly targeted and intensive over the period of interest. This use of multiple proxy records provides a more comprehensive understanding of the dynamic ecological legacies and human-environment relationship necessary to guide restoration. Setting current management into a broader historical context enhances the efficacy of restoration efforts focused on improving the ecological health and function of oak habitat at WUZ, while contributing to the network of key sites maintaining these priority oak habitats in the Pacific Northwest.

The death cap mushroom (Amanita phalloides) moves to a native tree in Victoria, British Columbia

Amanita phalloides (Vaill. ex Fr.) Link, the death cap mushroom, is an invasive ectomycorrhizal fungus in North America that was inadvertently introduced from Europe. Death cap mushrooms are highly toxic and have caused three recorded poisonings in British Columbia (BC), including one recent death. In BC, these mushrooms fruit mostly in urban environments in the greater Vancouver and Victoria areas under planted exotic broadleaf trees. In California, A. phalloides was demonstrated to also form ectomycorrhizas with a native oak species. Here we report that A. phalloides forms ectomycorrhizas with Quercus garryana, which is BC’s only native species of oak, and can fruit in association with this tree host. If death cap mushrooms spread in Q. garryana habitat, the risk for serious mushroom poisoning will increase, and mushroom harvesters, the medical community, and park managers will need to be made aware of this increased risk.

Research to policy: Enabling oak woodland restoration

are encouraged to report it via a dedicated CISR website. More information on this pest and the invasion can be found at http:// cisr.ucr.edu/palmarum.html. There’s currently no public funding for monitoring or con- trolling the weevil, however. Federal support likely won’t be available until the adoption of the next Farm Bill, currently slated for 2018. Hoddle is also applying for funding through the CDFA Specialty Crop grant program, and plans to apply for re- search funding from UC Agriculture and Natural Resources. While Hoddle radiates positive energy, he’s also distinctly realistic about the prospects for eradicating the South American palm weevil, given the large population in Tijuana, its flying ability, and the extent of the invasion already in the San Diego area. In the future, he said, control strategies may turn to de- fending selected, high-value trees using systemic insecticides that can kill weevil larvae. In Spain, he said, where the red palm weevil — native to Southeast Asia and a close relative of the South American palm weevil — are well-established, orna- mental Canary Island date palms in public areas are commonly fitted with showerhead-type applicators that douse a tree with insecticide every few months. c — Jim Downing Research news Research to policy: Enabling oak woodland restoration C Yana Valachovic UC and UCCE research on the impact of conifer encroachment helped facilitate policy changes that make it easier for California landowners to remove conifers from oak woodlands. alifornia black oak and Oregon white oak woodlands throughout California have been shrinking due to decades of conifer encroach- ment, which has led to a loss of wildlife habitat, biodi- versity and grazing land. Many years of fire suppression have created condi- tions that enable conifers to invade oak woodlands. Slowing the process of encroachment is difficult, as trees need to be removed manually, which is expen- sive. Additionally, landowners have been hindered in removing confers from oak woodlands by California’s Forest Practice Rules, which require that owners re- plant conifer trees after harvesting trees even when the goal is to promote oak restoration. A collection of policy changes adopted last year make it significantly easier for California landown- ers to manage this type of conifer encroachment. AB 1958, authored by Assemblymember Jim Wood (D-Healdsburg), removes permitting hurdles for re- moving small-diameter conifers from oak woodlands on a 7-year pilot-test basis starting January 1, 2018. Separately, the state Board of Forestry established a new timber-harvest rule for oak woodland restoration projects, effective January 2017, that allows landown- ers to remove conifers that have encroached on Oregon white and California black oak woodlands. “AB 1958, developed with the expertise of UC Cooperative 22 CALIFORNIA AGRICULTURE • VOLUME 71, NUMBER 1 Extension, allows private land owners to manage their land and preserve these valuable oak habitats,” said Wood. “It’s a great step forward in responsibly man- aging our environment.” UC Cooperative Extension (UCCE) worked directly with the Board of Forestry, the California legislature and interested stakeholders to facilitate these changes. UCCE also helped establish the scientific basis for the new rules by documenting the degree and nature of the encroachment in a three-year study completed in 2016. Under a UC Agriculture and Natural Resources competitive grant, UCCE Humboldt County director and forest advisor Yana Valachovic led a broad team of researchers that included area fire advisor Lenya Quinn-Davidson, UC Berkeley–based specialists Rick Standiford and Maggi Kelly and professor Matthew Potts, along with private landowners and collabora- tors from Humboldt State University and government agencies. “This is an exciting time for oaks and it has been great to help create science-based policy,” said Valachovic. “I am grateful for UC’s support. This much-needed scientific assessment has helped to de- velop awareness of these important habitat types in need of restoration.” The team evaluated the impact and extent of Douglas-fir encroachment in 10 oak sites across Humboldt and Mendocino counties, and documented the age structure and tree health of these oak stands. The team learned that most of the encroachment be- gan after 1940 and that the oaks are much older than the Douglas-fir trees. The researchers also studied factors that influenced encroachment, such as cli- mate and moisture, and mapped oak woodlands and compared them to historic photos. The data collected directly informed and gave confidence to the policy- makers working on the rule changes. c —Debbie Thompson

Oak mistletoe (Phoradendron villosum) is linked to microhabitat availability and avian diversity in Oregon white oak (Quercus garryana) woodlands

Mistletoes are parasitic or hemiparasitic flowering plants that parasitize woody plants around the globe. Important food and cover resources provided by mistletoes have been related to strong patterns of positive association between wildlife diversity and mistletoe density. Mistletoes also create microhabitat features known to be important to wildlife by causing deformations in their host trees. However, links between availability of mistletoe-formed microhabitat and wildlife diversity has not been well-studied. We investigated this relationship by quantifying microhabitat features and avian abundance and diversity related to infection by oak mistletoe (Phoradendron villosum (Nutt.) Nutt. ex Engelm.) in Oregon white oak (Quercus garryana Douglas ex Hook.). Quercus garryana woodlands support several avian species of conservation concern, so understanding the influence of mistletoe on wildlife habitat is critical. Our results suggest that (i) structural heterogeneity within tree crowns is positively associated with mistletoe load; (ii) avian species richness and abundance are positively associated with mistletoe load; and (iii) the fruit of P. villosum is an important food for Western Bluebird (Sialia mexicana) and other wildlife in late autumn and early winter. If a goal of restoration is to maintain habitat for oak-associated bird species, managers should consider the retention of some oaks hosting mistletoe.

Prescribed fire and conifer removal promote positive understorey vegetation responses in oak woodlands

Summary Fire‐prone woodlands and savannas world‐wide face management challenges resulting from fire exclusion and subsequent encroachment of fire‐sensitive trees. In the Pacific Northwest (USA), Quercus garryana oak woodlands and savannas are threatened by encroachment from the native conifer Pseudotsuga menziesii in the absence of fire. In the Bald Hills of Redwood National Park (California, USA), prescribed fire and conifer removal have been used to restore encroached woodlands. We examined the effects of encroachment and restoration on understorey vegetation, comparing four treatments: prescribed fire, prescribed fire and conifer removal, conifer removal, and encroached (control). Treatments including prescribed fire had the greatest native species richness. These two treatments also had the greatest non‐native species richness, at both the site level and the treatment level. Woodlands treated with conifer removal and no prescribed fire were intermediate in species richness and diversity compared to burned treatments and encroached woodlands. Encroached woodlands had diminished richness and diversity compared to all restoration treatments. Non‐metric multidimensional scaling (NMS) ordination demonstrated that conifer basal area, conifer litter and fine wood were associated with low species richness and diversity and that elevation and thatch were associated with higher species richness and diversity. Indicator species analysis identified that most native species and non‐native species were associated with burned woodlands that were never encroached. Synthesis and applications. Our results suggest that both prescribed fire and conifer removal have benefits for understorey plant communities, increasing species richness, diversity and cover in oak woodlands and shifting understorey communities from forest‐associated species to more woodland‐associated species. Restoration of remnant Quercus garryana oak woodlands is complicated by the persistence and abundance of non‐native herbaceous plants.

A Tale of Two Sisters: Family Histories from the Strait Salish Borderlands

Based on legal and genealogical records, this microhistory chronicles the difficult choices between whiteness and Indianness made by two Salish sisters and their biracial children in order to maintain their kinship networks throughout the Salish Sea borderlands between 1865 and 1919. While some of these choices obscured individual family members from historical records, reading their lives in tandem with other family members’ histories reveals remarkable persistence in the midst of dramatic racial and political transformation. Focused primarily on San Juan Island residents, this article suggests that indigenous and interracial family histories of the Pacific Northwest and other borderland regions in the North American West can be more fully understood when examined collectively rather than in isolation. Such a model emphasizes the importance of personal borderlands histories and allows historians to overcome the archival silences so common among people living on the margins. Family histories from the San Juan Islands are as distinctive as the slow-growing Garry oaks native to the valleys and meadow slopes of the island chain. One of those knotted and gnarled oaks stands near the center of San Juan Island, on a slight rise that yields a panoramic view of the valley farmed by Danish immigrant Peter Jewell and his Strait Salish wife, Fanny, in the 1860s and 1870s. (See figure 1.) Standing beneath its more than sesquicentennial branches, one can imagine the laughter of Fanny’s daughters as they played in its shade with maternal cousins who lived a mile or so away. Fanny might have served lunch under the tree to day laborers between …

Relative vulnerability to climate change of trees in western North America

Many recent changes in tree species distributions, mortality, and growth rates have been linked to changes in climate. Managing forests in the face of climate change will require a basic understanding of which tree species will be most vulnerable to climate change and in what ways they will be vulnerable. We assessed the relative vulnerability to climate change of 11 tree species in western North America using a multivariate approach to quantify elements of sensitivity to climate change, exposure to climate change, and the capacity to adapt to climate change. Our assessment was based on a combination of expert knowledge, published studies, and projected changes in climate. Of the 11 species, Garry oak (Quercus garryana) was determined to be the most vulnerable, largely because of its relatively high sensitivity. Garry oak occupies some of the driest low woodland and savanna sites from British Columbia to California and is highly dependent on disturbances, such as periodic, low intensity fire. Big leaf maple (Acer macrophyllum) was determined to be the least vulnerable, largely because of its adaptive capacity. Big leaf maple can reproduce quickly after disturbances and its seeds can disperse long distances potentially allowing it to move in response to a changing climate. Our analyses provide a framework for assessing vulnerability and for determining why some species will likely be more vulnerable than others. Such information will be critical as natural resource managers and conservation practitioners strive to address the impacts of climate change with limited funds.

Climate-driven changes in forest succession and the influence of management on forest carbon dynamics in the Puget Lowlands of Washington State, USA

Projecting the response of forests to changing climate requires understanding how biotic and abiotic controls on tree growth will change over time. As temperature and interannual precipitation variability increase, the overall forest response is likely to be influenced by species-specific responses to changing climate. Management actions that alter composition and density may help buffer forests against the effects of changing climate, but may require tradeoffs in ecosystem services. We sought to quantify how projected changes in climate and different management regimes would alter the composition and productivity of Puget Lowland forests in Washington State, USA. We modeled forest responses to four treatments (control, burn-only, thin-only, thin-and-burn) under five different climate scenarios: baseline climate (historical) and projections from two climate models (CCSM4 and CNRM-CM5), driven by moderate (RCP 4.5) and high (RCP 8.5) emission scenarios. We also simulated the effects of intensive management to restore Oregon white oak woodlands (Quercus garryana) for the western gray squirrel (Sciurus griseus) and quantified the effects of these treatments on the probability of oak occurrence and carbon sequestration. At the landscape scale we found little difference in carbon dynamics between baseline and moderate emission scenarios. However, by late-century under the high emission scenario, climate change reduced forest productivity and decreased species richness across a large proportion of the study area. Regardless of the climate scenario, we found that thinning and burning treatments increased the carbon sequestration rate because of decreased resource competition. However, increased productivity with management was not sufficient to prevent an overall decline in productivity under the high emission scenario. We also found that intensive oak restoration treatments were effective at increasing the probability of oak presence and that the limited extent of the treatments resulted in small declines in total ecosystem carbon across the landscape as compared to the thin-and-burn treatment. Our research suggests that carbon dynamics in this system under the moderate emission scenario may be fairly consistent with the carbon dynamics under historical climate, but that the high emission scenario may alter the successional trajectory of these forests.

Effects of topoclimatic complexity on the composition of woody plant communities.

Topography can create substantial environmental variation at fine spatial scales. Shaped by slope, aspect, hill-position and elevation, topoclimate heterogeneity may increase ecological diversity, and act as a spatial buffer for vegetation responding to climate change. Strong links have been observed between climate heterogeneity and species diversity at broader scales, but the importance of topoclimate for woody vegetation across small spatial extents merits closer examination. We established woody vegetation monitoring plots in mixed evergreen-deciduous woodlands that spanned topoclimate gradients of a topographically heterogeneous landscape in northern California. We investigated the association between the structure of adult and regenerating size classes of woody vegetation and multidimensional topoclimate at a fine scale. We found a significant effect of topoclimate on both single-species distributions and community composition. Effects of topoclimate were evident in the regenerating size class for all dominant species (four Quercus spp., Umbellularia californica and Pseudotsuga menziesii) but only in two dominant species (Quercus agrifolia and Quercus garryana) for the adult size class. Adult abundance was correlated with water balance parameters (e.g. climatic water deficit) and recruit abundance was correlated with an interaction between the topoclimate parameters and conspecific adult abundance (likely reflecting local seed dispersal). However, in all cases, the topoclimate signal was weak. The magnitude of environmental variation across our study site may be small relative to the tolerance of long-lived woody species. Dispersal limitations, management practices and patchy disturbance regimes also may interact with topoclimate, weakening its influence on woody vegetation distributions. Our study supports the biological relevance of multidimensional topoclimate for mixed woodland communities, but highlights that this relationship might be mediated by interacting factors at local scales.

Invasive Scotch broom (Cytisus scoparius, Fabaceae) and the pollination success of three Garry oak-associated plant species

A growing number of studies have reported an effect of invasive species on the pollination and reproductive success of co-flowering plants, over and above direct competition for resources. In this study, we investigate the effect of the invader Scotch broom (Cytisus scoparius) on the visitation, pollen deposition, and female reproductive output of three co-flowering species (two native, one exotic) of the critically endangered Garry oak grassland ecosystem on the Saanich peninsula of Vancouver Island. The presence of C. scoparius was largely neutral, with the exception of some facilitation of pollen deposition to the native Camassia leichtlinii, the one species exhibiting pollinator overlap with Scotch broom. Yet, this pattern occurred despite a decreased visitation rate from pollinators. There was little observed effect of the invader on the native Collinsia parviflora or the exotic Geranium molle. Because broom was not favourited by any of the observed pollinators, this study provides evidence that the spread of Scotch broom is not due to the reduction of pollination success of natives nor is C. scoparius likely to be facilitating the pollination of other exotics in Garry oak ecosystem remnants.

Paleoecology and fire history of Garry oak ecosystems in Canada: implications for conservation and environmental management

Garry oak (Quercus garryana) ecosystems are listed as “at-risk” or endangered throughout their global range. In Canada, they are an umbrella for over one hundred species that are endangered to some degree. In order to effectively recover or allow these species to persist where possible, understanding of the ecological processes essential to their ongoing survival is needed. Fire suppression, aboriginal land-use, climate change, and post-colonial development have lead to drastic changes in the structure and amount of Garry oak ecosystems in North America. This paper presents new data using pollen and charcoal analysis to reconstruct past vegetation change and disturbance regimes for Garry oak and coastal Douglas-fir ecosystems over the past ~500 years. Significant change in vegetation at the study sites has occurred with the greatest change in community structure and decline in Garry oak ecosystems occurring after the end of the Little Ice Age and as the impacts of western colonization occurred in the mid to late 19th century. Understanding mean fire return intervals (MFRI), ecosystem dynamics over time, and the role of people in this ecosystem structure is critical to the success of conservation efforts that are designed to ensure the long-term survival of these communities. The MFRI, inferred from charcoal analysis, ranges from 26 to 41 years on Vancouver and Pender Islands, Canada. Our results indicate that fire suppression, cessation of aboriginal land-use, climate change, western colonization and subsequent intensification of land-use has greatly altered Garry oak ecosystems. This study illustrates the utility of using paleoecological investigations to help in the development of land management strategies and prescribed burn plans.

A new model to simulate climate-change impacts on forest succession for local land management.

We developed a new climate-sensitive vegetation state-and-transition simulation model (CV-STSM) to simulate future vegetation at a fine spatial grain commensurate with the scales of human land-use decisions, and under the joint influences of changing climate, site productivity, and disturbance. CV-STSM integrates outputs from four different modeling systems. Successional changes in tree species composition and stand structure were represented as transition probabilities and organized into a state-and-transition simulation model. States were characterized based on assessments of both current vegetation and of projected future vegetation from a dynamic global vegetation model (DGVM). State definitions included sufficient detail to support the integration of CV-STSM with an agent-based model of land-use decisions and a mechanistic model of fire behavior and spread. Transition probabilities were parameterized using output from a stand biometric model run across a wide range of site productivities. Biogeographic and biogeochemical projections from the DGVM were used to adjust the transition probabilities to account for the impacts of climate change on site productivity and potential vegetation type. We conducted experimental simulations in the Willamette Valley, Oregon, USA. Our simulation landscape incorporated detailed new assessments of critically imperiled Oregon white oak (Quercus garryana) savanna and prairie habitats among the suite of existing and future vegetation types. The experimental design fully crossed four future climate scenarios with three disturbance scenarios. CV-STSM showed strong interactions between climate and disturbance scenarios. All disturbance scenarios increased the abundance of oak savanna habitat, but an interaction between the most intense disturbance and climate-change scenarios also increased the abundance of subtropical tree species. Even so, subtropical tree species were far less abundant at the end of simulations in CV-STSM than in the dynamic global vegetation model simulations. Our results indicate that dynamic global vegetation models may overestimate future rates of vegetation change, especially in the absence of stand-replacing disturbances. Modeling tools such as CV-STSM that simulate rates and direction of vegetation change affected by interactions and feedbacks between climate and land-use change can help policy makers, land managers, and society as a whole develop effective plans to adapt to rapidly changing climate.

The Dendroclimatological Potential of Willamette ValleyQuercus garryana

We develop a 341-year Oregon white oak (Quercus garryana Dougl.) tree-ring chronology in Oregon's Willamette Valley to evaluate climate-growth relationships and determine the species' dendroclimatological potential at our site and in the surrounding region. The standardized and residual chronologies exhibit significant positive correlations with previous-year April and May temperatures, inverse correlations with previous-year spring precipitation and summer PDSI, a positive correlation with current-year July precipitation and summer PDSI, and inverse correlations with current-year June temperatures. The strength of these relationships varies over time. Significant shifts in the chronologies' mean and variance align with phase changes in the Pacific Decadal Oscillation (PDO), with lower and more variable growth during the warmer, drier positive phase of the PDO over the instrumental record. The absence of similar shifts prior to the 1900s, suggests a lack of temporal consistency in the expression of PDO variability at our site. The strong crossdating at our site reflects a cohesive climate signal, and the climate analysis illustrates the potential to develop proxy data over multiple centuries. Together, these results indicate a potential to expand the network of currently available climate proxy data by utilizing Q. garryana in dendroclimatological research.

Phytoliths as indicators of plant community change: A case study of the reconstruction of the historical extent of the oak savanna in the Willamette Valley Oregon, USA

The Oregon white oak savanna, once common in Oregon's Willamette Valley, has been reduced to less than 1% of its former extent. For ecological restoration purposes, we used phytolith analysis to establish both historical vegetation composition and structure at the Jim's Creek research site in Oregon, USA. We sampled the soil at 47 selected plots, extracted the phytoliths, and determined the composition of the phytolith assemblages. Based on the ratios of grass and tree phytoliths in the samples, each site was assigned to one of three ecotopes that, through phytoliths, describe the historic vegetation mosaic. By reconstructing the spatial distribution of historic vegetation types, we were able to confirm the pattern of conifer encroachment on former savanna as suggested by other studies.

Characterization of Fast Pyrolysis Products Generated from Several Western USA Woody Species

Woody biomass has the potential to be utilized at an alternative fuel source through its pyrolytic conversion. Here, fast pyrolysis bio-oils derived from several western USA woody species are characterized by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) to determine molecular-level composition. The composition and properties (pH, electrical conductivity, and elemental analyses) of the biochar byproduct were also determined. The bio-oils are comprised mainly of Ox species. Oak (Quercus garryana Douglas ex Hook), mixed conifer (Pseudotsuga menziesii Mirb. Franco, Tsuga heterophylla (Raf.) Sarg, Abies concolor (Gord. & Glend.) Lindl. ex Hildebr.), and scotch broom (Cytisus scoparius (L.) Link) bio-oils contain lower Ox (O1–O7) species that exhibit bimodal distributions whereas mixed conifer feedstock from a fire salvage harvest contains a larger range of Ox species (O2–O13) that exhibit a mainly monomodal distribution. Boron-containing species in the pyrolysis oils were also identified for the first time by FT-ICR MS. Biochar analysis revealed that all biochars had similar pH values (∼7–8); however, the electrical conductivity and elemental analyses varied across the samples. Understanding the composition of pyrolysis byproducts will help direct their uses to the most appropriate locations.

Environmental change in Garry oak (Quercus garryana) ecosystems: the evolution of an eco-cultural landscape

Globally, colonialism resulted in the suppression of aboriginal land manage- ment practices, abetted by the concept of terra nullius, ''belonging to no one''; the belief that aboriginal people had little influence on or ownership of the land. Until recently, this ideology was entrenched in resource management and policy. Traditional ecological knowledge, historical ecology, archaeology, and palaeoecological research have shown these assumptions to be wrong. In this paper we take a multidisciplinary approach (bio- geography, paleoecology, dendrochronology, and bioclimatic envelope modeling) to better understand the role of climate and fire in the formation of eco-cultural landscapes. We synthesize results from pollen and charcoal analysis in Garry oak ecosystems that indicate there were continuous and frequent prescribed burning events, with more severe fires occurring every 26-41 years in southwest British Columbia throughout the Anthropocene (*last 250 years) that substantially altered forest structure and composition. These results are consistent with stand age reconstructions in BC and Washington with Garry oak establishment beginning *1850 AD, corresponding with modern fire exclusion, aboriginal population decline, and end of the Little Ice Age. Douglas-fir recruitment has been con- tinuous since *1900, with succession of oak woodland to closed conifer forest at most sites. These findings indicate that the structure of many Garry oak ecosystems have been profoundly influenced by eco-cultural practices. Overwhelming evidence indicates that in many cases these ecosystems are dependent on prescribed fire for their open structure. In

Macrolichen Communities of <em>Quercus garryana</em> in the Puget Trough and Columbia River Gorge Areas of Washington State

We investigated macrolichen diversity on Quercus garryana at ten sites in the Puget Trough and Columbia River Gorge areas of Washington. The known ranges of some oak-associated species are expanded within Washington and occurrences of several species new to the state are reported. We identified 111 lichen taxa, 80 of which occurred at more than one site and three species, Fuscopannaria pulveracea, Placidium fingens and Collema quadrifidum , which are reported for the first time for Washington. We report four additional species, Bryoria furcellata, Dendriscocaulon intricatulum, Usnea cavernosa and Waynea californica , which are reported from oaks on two or fewer sites in Washington prior to this study. We compiled records from herbaria and other Washington oak lichen studies to evaluate the rarity of observed species and potentially rare species known from nearby locations. Using macrolichens we developed an Index of Ecological Continuity for oak habitats in Washington to help land managers assess the health of the lichen communities on oaks. We also recorded lichen species diversity and abundance in air quality monitoring plots at six of our sites in order to assess the threat level from increasing air pollution to oak lichens. We discuss the effects of management practices on lichen diversity and abundance at oak sites and suggest species of interest for future conservation efforts.

Novel ecosystems in the restoration of cultural landscapes of Tl’chés, West Chatham Island, British Columbia, Canada

The small archipelago of Tl’ches, in coastal British Columbia, has gone through drastic social-ecological change culminating in the decline of traditional management practices, invasion of exotic plant species and, in the early 1960s, land abandonment. This is a common trend in cultural landscapes around the world. Cultural landscapes have great social-ecological significance, including cultural safeguarding and renewal, as well as maintenance of biodiversity, ecosystem functions and services, making them objects of special attention in conservation and restoration efforts. This study investigates the relationship between the Lekwungen people and heavily altered ecosystems in the context of ecological restoration for the cultural landscapes of Tl’ches. In order to thoroughly explore the ecological, social and cultural aspects and processes involved in the restoration of Tl’ches, this study combined different environmental sciences methodologies, including historical and archival research, semi-structured interviews and participatory observation with Lekwungen participants, as well as ecological field assessments and an innovative mapping approach termed Terrestrial Cultural Ecosystem Mapping (TCEM). This study generated historical and spatial references for ecosystem and land use change in West Chatham Island, as well as cultural and ecological understandings to support restoration. Although important native species such as Camassia spp. are still thriving, present-day ecosystems on this island are heavily altered from the natural Garry oak ecosystem reference sites and are largely dominated by exotic invasive shrubs and graminoid species. This investigation indicates that the Lekwungen value both the historical ecological conditions of the island and particular types of the present-day novel or hybrid ecological states, such as the overgrown heritage orchard and nonnative berries found on the islands. Present-day ecosystems of Tl’ches are a result of a hybrid management system (traditional and conventional), coupled with land abandonment for many decades. Restoration of Tl’ches must involve both ecological and cultural components. Therefore, intervention strategies should consider the incorporation of novel and hybrid ecosystems (i.e. naturalized exotic species) into a restoration plan for ecological, cultural, historical, and subsistence values.

Effect of Plant Sterols and Tannins on Phytophthora ramorum Growth and Sporulation

Elicitin-mediated acquisition of plant sterols is required for growth and sporulation of Phytophthora spp. This study examined the interactions between elicitins, sterols, and tannins. Ground leaf tissue, sterols, and tannin-enriched extracts were obtained from three different plant species (California bay laurel, California black oak, and Oregon white oak) in order to evaluate the effect of differing sterol/tannin contents on Phytophthora ramorum growth. For all three species, high levels of foliage inhibited P. ramorum growth and sporulation, with a steeper concentration dependence for the two oak samples. Phytophthora ramorum growth and sporulation were inhibited by either phytosterols or tannin-enriched extracts. High levels of sterols diminished elicitin gene expression in P. ramorum; whereas the tannin-enriched extract decreased the amount of 'functional' or ELISA-detectable elicitin, but not gene expression. Across all treatment combinations, P. ramorum growth and sporulation correlated strongly with the amount of ELISA-detectable elicitin (R (2) = 0.791 and 0.961, respectively).