|BOTANICAL ELECTRONIC NEWS|
|No. 298 November 18, email@example.com||Victoria, B.C.|
Garry oak ecosystems in Canada form mosaics with maritime meadows, coastal bluffs, vernal pools, grasslands, rock outcrops, and transitional forests. The current global distribution of Garry oak ecosystems spans an extensive north-south range, from southwestern British Columbia to southern California. The Canadian distribution is limited to southeastern Vancouver Island, the Gulf Islands, and outlier stands on Savary Island and in the Fraser Valley, all within British Columbia. A Mediterranean-like climate prevails over most of the Canadian range of Garry oak ecosystems. Different species associated with today's Garry oak ecosystems arrived at different times following the last glacial retreat. Current climate and ecosystem models predict that much of what is currently Douglas-fir forest in coastal British Columbia will likely be replaced by Garry oak and related ecosystems within the next half century.
The Garry oak landscape in British Columbia is located within the traditional territories of the Coast Salish First Peoples. Prior to European settlement, First Peoples used regular burning to maintain the open vegetation structure favourable to camas (Camassia quamash and C. leichtlinii), the primary vegetable food. Grazing of domestic animals, land clearing, and fire suppression followed European settlement. In the last 150 years, agricultural, residential, and industrial development have vastly reduced the extent of Garry oak ecosystems. Current estimates suggest that only about 1-5 % remains in a near-natural condition. Remnant habitat is under threat from continued urban development. Garry oak is the only native oak in British Columbia. On moister sites, the oaks tend to be out-competed by faster growing conifers unless maintained by disturbance. Acorns are dispersed primarily by Steller's jays, Cyanocitta stelleri, in British Columbia. Deep taproots confer a high degree of drought tolerance to Garry oak seedlings. Mature oaks are shade intolerant. Oaks reproduce vegetatively by sprouting and from underground rhizomes as well as by seed. Oak regeneration may be a problem for Garry oaks in British Columbia, but this has not been documented.
Habitat fragmentation results in small parcels of ecosystems that are subject to risks related to patch size and patch isolation. The ability of larger patches to support larger populations of species is important for preventing local extinctions. In general, smaller animals require less space than larger animals. Carnivores tend to require more space than omnivores, who in turn require more space than herbivores. The ability of the surrounding landscape to help support species depends upon the characteristics of the landscape. In British Columbia, Garry oak patches surrounded by highly developed areas contain fewer species of birds than patches in less developed areas. Breeding populations of birds associated with oak and grassland habitats have declined in the urban Victoria area since the 1970's.
The history of oak-prairie ecosystems throughout North America is inextricably linked with fire. Relatively frequent, low-intensity fires were largely a result of landscape-management activities of local First Peoples. Fire suppression following European settlement has resulted in dramatic changes to the composition, structure, and function of the ecosystems. Without fire, many prairies convert to shrublands and savannahs, and savannahs convert to closed canopy woodlands and conifer forests. Large- scale conversions of prairie and oak savannah have been documented in the United States. Fire has been described as the most serious ecological problem facing remnant Garry oak stands that are protected from development. Stand dynamics have not been described in any detail for Garry oak ecosystems in Canada, but similar patterns have been observed at some locations. Prescribed fire has been used as a restoration tool at some Garry oak sites in the United States. The efficacy of fire as a restoration tool is equivocal because some invasive plants are favoured by fire. The responses of vertebrates to a fire regime are largely mediated by fire effects on vegetation structure. Invertebrates are vulnerable to direct fire-caused mortality.
Biological invasions are among the most serious modern ecological problems. Invasions are most pernicious when they cause ecosystem-level changes. The prevalence of exotic plants in Garry oak and associated ecosystems in British Columbia has been documented in a number of studies. Sampling found up to 82 % of herbaceous cover composed of invasive species. Scotch broom (Cytisus scoparius) and other invasive shrubs pose some of the most serious threats to the ecosystems. Exotic grasses dominate the herbaceous flora at many if not most sites. A variety of management tools have been employed for control of different exotic plants. Overall, efforts have been resource intensive and success has been limited. The European starling (Sturnella neglecta) has been implicated in the decline of native cavity-nesting bird species. Twenty one percent of all mammal species in Garry oak and associated ecosystems in British Columbia are exotic. The introduced eastern gray squirrel (Sciurus carolinensis) may potentially contribute to declines of the native red squirrel (Tamiasciurus hudsonicus) and compete with a number of native animal species for acorns. Four invasive insects have caused, or have the potential to cause, serious damage to Garry oak trees. Evidence for the potentially devastating impacts of introductions also exists in lesser-known taxonomic groups. Earthworms on southeastern Vancouver Island are almost exclusively introduced species. The introduced black slug (Arion ater) may be harming populations of some rare plants. In California, a fungus associated with an oak epidemic that has spread hundreds of miles in 5 years may be an introduced exotic species.
In conclusion, the range of biological and cultural values vested in Garry oak and associated ecosystems confers great significance to ecosystem conservation. The extent and rate of decline imparts urgency to the development and implementation of conservation initiatives. Research is needed to fill the many information gaps, but conservation actions, based upon the best available knowledge, must be applied in the meantime.
[This was the abbreviated Executive Summary of Fuchs, Marilyn A. 2001. Towards a Recovery Strategy for Garry Oak [Quercus garryana] and Associated Ecosystems in Canada: Ecological Assessment and Literature Review. Technical Report GBEI/EC00030. Environment Canada, Canadian Wildlife Service, Pacific and Yukon Region. http://www.goert.ca/assets/docs/litreview.pdf
The report gives an extensive bibliography of various aspects of Garry oak.
See also http://www.fs.fed.us/pnw/olympia/silv/publications/oak/bibliography/quercus_garryana.htm
Relatively little is known about the reproductive potential, silviculture, or ecology of Oregon white oak (Quercus garryana). Oregon white oak ranges from British Columbia to southern California mostly west of the Cascade-Sierra crest in a wide range of soil and moisture conditions. Oregon white oak habitat has been diminishing since the beginning of Euro-American settlement due to conversion to agriculture, urban areas, other forest types and introduction of exotics (Ewing 1997, Chappell & Crawford 1997, Tveten & Fonda 1999).
Little is known about Oregon white oak acorn production, even though acorns are a rich source of food for many animals. Acorns are an especially important winter food for western gray squirrels, which are threatened in Washington (Roderick 1987). Information is needed on when acorn production begins, average crop sizes, regularity of flowering and variability within and between stands and locations (Stein 1990). It is not known if acorn crop variation is primarily controlled by variation in flower production, or success of flowering and fruit production.
Anecdotal information indicates that Oregon white oak produces heavy seed crops on an irregular basis. Heavy seedcrop years appear to be followed by one or more years of poor productivity, and good and bad years are somewhat synchronized over broad geographic areas. Understanding the factors that influence production of Oregon white oak acorns could help managers increase acorn crop size as many of the factors can be altered by management activities.
To determine tree, stand, and environmental characteristics influencing acorn production, we surveyed 284 trees in September and October 1999. Surveyed trees extended from Whidbey Island, Washington, to Roseburg, Oregon, and ranged in age from 11 to over 300 yr. Acorn production was ranked on a 1-4 scale (non-producing to heavily producing).
In general acorn production in our sample was influenced by competition , moisture, age, and fire history. Acorn production started around 20 yr and plateaued around 80 yr. Productivity tended to be highest on well watered, well drained sites on trees at least 6080 yr old that were growing under little competition from neighbors. Trees in urban parks with fertilization or irrigation also produced well.
As competition increased, crown contact increased and tree shape changed. Oregon white oak is not shade tolerant and loses lower limbs under lateral shade, resulting in the vase shape typical of trees growing in dense stands. Crown shape, was an easy variable to code and a good predictor of productivity. Trees with vaseshaped crowns typical of dense forest stands produced fewer acorns than those with columnar or mushroomshaped crowns typical of more open areas. Open-grown trees growing in well-drained, loamy soils had the highest productivity within natural settings. We assume shape was important because it serves as an integrator of the competitive environment around the tree for an extended time period.
In our sample open-grown trees are better acorn producers than crowded trees. We do not know what level of stand density would result in the best productivity per unit area. A forest of vase shaped oak trees may have higher acorn production per unit of land than a savanna of mushroom shaped trees because every area in the forest is producing acorns. The relationships between tree and standbased measures of acorn productivity will need to be evaluated to provide managers with better tools to make decisions.
Underburning is a useful tool for reducing shrub and tree competition, but may affect acorn productivity. This is important when managing acorn-consuming wildlife. Our data suggest that underburning may reduce acorn production in the year following burning, but may contribute to higher production 6-10 yr after underburning. Trees underburned 6-10 yr before the survey produced better than trees not underburned or trees underburned more recently. This relationship implies a reproductive benefit to trees following underburning and recovery, but the duration of the benefit is unknown. Most of the underburned trees in this study had a shrub understory component at the time of burning, which made fires more intense. Low intensity grass fires probably cause less tree damage and may not result in an initial loss of acorn production. Acknowledgments We thank Fort Lewis, and the Fort Lewis Forestry Department, for providing financial and logistical support and the landowners and volunteers that made data collection over this wide geographic area possible.
Condensed from: Peter, D., and C. Harrington. 2002. Site and tree factors in Oregon white oak acorn production in western Washington and Oregon. Northwest Science 76(3): 189-201.
For more information go to: http://www.fs.fed.us/pnw/olympia/silv/oaksurvey/oak.htm
Regeneration of Garry oaks (Quercus garryana) may be inadequate to sustain oak populations. Processes that mediate oak regeneration can be influenced by where acorn hoarding animals take acorns and how deep the acorns are buried at these hoarding sites. I planted acorns to determine the role of habitat type and burial depth on emergence and first-year survival of Garry oak seedlings. In all habitats that I examined, vertebrates removed > 53% of acorns placed on the ground surface. However, in approximately one half of the habitats, vertebrates removed <49 % of acorns buried in the ground cover or soil. Predation on buried acorns was high in habitats with sparse herb, dense shrub, and moderate to high tree cover. Predation on buried acorns was low in habitats with various structural characteristics, including those with dense herb cover and sparse shrub or tree cover. The mortality rate of buried acorns that were not removed by predators was low (<17%) in all but one habitat. Perhaps because of desiccation, the mortality rate of surface acorns was > 40 % in all but one habitat. Regardless of burial depth, once seedlings emerged, seedling survival was > 65 % in most habitats. Some habitats with high seedling emergence had relatively low seedling survival, and vice versa. In habitats on a south facing slope, characterized by rocky outcrops and absence of conifers, many seedlings died from desiccation. Other seedling mortality may have been caused by shoot browsing, root browsing, or insect herbivory. Seedling survival was not related to percent cover of overstorey vegetation, indicating that first year Garry oak seedlings were not protected by shade and can survive in habitats with limited light.
I observed harvesting, transporting, and caching of Garry oak (Quercus garryana) acorns by Steller's Jays (Cyanocitta stelleri) to assess the role of the jays in acorn dispersal. I watched Steller's Jays that I encountered as I traversed 2 study sites in British Columbia during August, September, and October 1994. I also classified substrates and habitats and described vegetation structure at cache sites and at locations along transects in the study sites. The jays used visual, tactile, and perhaps aural cues to select mature, relatively undamaged acorns for caching. Jays cached acorns between a few centimetres and at least 600 m from harvest locations and probably transported some acorns more than 1 km. Scattered trees in a meadow were used by jays as stopover points during transport journeys and appeared to facilitate acorn dispersal. More than 77 % of acorns were cached on their sides, which permits unimpeded extension of the epicotyl. Virtually all cached acorns were buried in the substrate and 88-92 % were fully hidden from view. Seventy five-76% of acorns were cached in the ground cover and only one acorn was cached more than 1 cm below the soil surface. Hidden, buried acorns are less likely to be taken by acorn predators or desiccate than those on the surface. Steller's Jays did not prefer or avoid substrates (rock, wood) unsuitable for seedling establishment. Steller's Jays preferred locations with extensive tree and shrub cover and sparse herb cover for caching acorns. All habitat types in the study sites characterized by this vegetation structure were used in greater proportion than they were available. Steller's Jays avoided locations with sparse tree cover, sparse shrub cover, or dense herb cover. Habitats preferred by Steller's Jays are unfavourable for seedling emergence because a high proportion of acorns buried in these habitats are subsequently removed by acorn predators. Low light levels in preferred habitat may also be unfavourable for survival and growth of older Garry oak seedlings and saplings. Although jays preferred some habitat types, approximately half of the cached acorns were distributed among nonpreferred habitats. Survival of acorns and first year seedlings is relatively high in some of these nonpreferred habitats, and many have more available light than habitats preferred by Steller's Jays. Use of non-preferred habitats may be essential for effective acorn dispersal by Steller's Jays and may be facilitated by juxtaposition of patches of preferred and non preferred habitats. Although less than 2 % of cached acorns produced seedlings, individual Steller's Jays probably cache thousands of acorns per season and are probably responsible for the presence of Garry oak seedlings far from mature oaks. Steller's Jays are probably the primary dispersal agent for Garry oaks in British Columbia, but this dispersal system may be less effective than those of oaks dispersed by other species of jays. Irregular occupation of Garry oak habitats in B.C. by Steller's Jays and habitat preferences of the jays place substantial constraints on the numbers of acorns buried in suitable habitats.
From: Frank Lang
Subject: Fw: Of Frank Lang and Garry oaks
Adolph, In an effort to stamp out parochialism, I have been fighting a losing battle to get folks to use Garry oak instead of Oregon white oak. Thought you might be interested in Darren Borgias' reaction to my proposal. As far as I know, he is not in favor of calling Douglas-fir, Oregon false hemlock. Would this (with his permission of course) be a good BEN item? Thought you might "enjoy" it, in any event. - Frank Lang
From: Darren Borgias [firstname.lastname@example.org]
Subject: What's in a name: an opinion on the importance of the common name "Oregon white oak" for Quercus garryana, or Who was Garry, anyway? [posted here with the author's permission]
Plants named after people, typically historically important but now somewhat obscure botanists, collectors, benefactors, friends, etc., represent an important honorary historical marker, and may indeed offer important scientific insight into a species. In many cases, however, that marker is not as useful as more pertinent morphological, biological, ecological, or evolutionary references in the common name. This is born out repeatedly in the common names of plants. A quick glance at a list of trees of California would indicate that most trees with scientific names honoring people do not retain the honored person's name in common use. For example, consider Douglas fir (named for Menzies), sugar pine (Lambert), California black oak (Kellogg), Pacific dogwood (Nuttall), madrone (Menzies), blue oak (Douglas), interior live oak (Wislizenus) , mountain hemlock (Mertens). Should all of these be renamed in common use as well?
The center of distribution for Oregon white oak is Oregon, especially considering what Oregon implies in terms of the historic Oregon Territory, an important geographic and ecological attribute. Hundreds of thousands of people live here in Oregon among the rounded lobed leaves of the oaks. And millions more in the surrounding states and the extreme southern corner of a Canadian province nearby, where the range of the oak extends, should know that the center of distribution for the tree is Oregon. Millions more around the world know about Oregon. And Oregon is not, for example, the East Coast, or the Arctic, or subsaharan Africa, or the Canadian midwest prairies around Winnipeg.
The "Oregon white oak" is just that. It is a white oak, with rounded leaf lobes, not a black oak, or a red oak, or a cork oak, or an evergreen oak, or huckleberry oak, or a tan oak. This is an important distinction about which "Garry" tells us little. Who was Garry, again? Who but a few botanical wizards care particularly? Is this oak to be confused with the oak found in Gary Indiana?
Perhaps it is sad that the information provided in "Oregon white oak" on the range and character of the oak is more useful to a user of common names than knowledge of the honor bestowed by David Douglas on his friend Nicholas Garry, then director/deputy governor of the Hudson's Bay Company, and for whom the city of Winnipeg was once named Fort Garry (but it was changed).
It is not surprising that the preference for the use of "Garry oak" appears perhaps somewhat provincial, expressed most strongly by Canadians and some USA citizens trained in or in close proximity to Canada. It must be somewhat galling that the predominant usage throughout the vast majority of the range of the plant fails to recognize an important icon of the British Empire and the Canadian historic experience. If ever I named a new plant species, which is not likely, I might well choose to honor certain significant botanists in my life, Lang and Taylor, among them, but if I did, I would also offer a common name based on geography, ecology, morphology anything to help identify and provide information about the species. Common names should be useful, and not necessarily direct translations of the scientific name. And besides all this, no one has proposed to remove the honor bestowed by Douglas on his friend Garry by changing the specific epithet.
EPILOGUE: Who was Garry, anyway?
From: Page 10 in Wallace, W. Stewart (General Editor) 1948. The Encyclopedia of Canada, Vol. 3: Gabarus - Laurierville. Toronto.
Garry, Nicholas (1782?-1856), deputy governor of the Hudson's Bay Company (1822-1835), was born in England about 1782, the natural son of Nicholas Langley (d. 1783) and Isabella Garry, whose name he took. He was brought up by his uncle, Thomas Langley, who became a director of the Hudson's Bay Company in 1807; and he himself became a director in 1817. In 1821 he was selected to visit Canada to supervise the amalgamation of the Hudson's Bay Company with the North West Company; and the Diary of his journey has been printed in the Transactions of the Royal Society in Canada for 1900. From 1822 to 1835 he was deputy-governor of the Hudson's Bay Company; but in 1835 he became of unsound mind, and his affairs were administered by the master in chancery from about 1839 until his death at Claygate, Surrey, England, on December 24, 1856. Fort Garry [=Winnipeg] and other places in western Canada were named after him.
Post Scriptum: Not speaking about Garry oak (Quercus garryana), also known as Oregon white oak, and Silktassel (Garrya). Both names were proposed by David Douglas, apparently to acknowledge the help of Nicholas Garry and the Hudson's Bay Company during his travels through the Pacific Northwest. - AC
Kew Gardens has released the first stage in a new online information resource discovery service called ePIC, the electronic Plant Information Centre. From the ePIC interface at:
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This unique resource currently holds more than 145,000 individual records, mostly for published material like monographs and pamphlets. About 700 of the ca. 4,000 periodical titles held at Kew have entries on the catalogue, mainly those acquired by purchase.
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