Viscin Cells in the Dwarf Mistletoe Arceuthobium ... - Davidsonia

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88 approximately 6000 years ago during the Holocene period, when the region experienced a warmer and dryer climate than at present (Allen et al. 1999). When the coastal climate changed to the wetter and cooler weather that we experience today, the hardwood ecosystems were outcompeted by conifers in many areas. Garry oaks and their associated plant communities persisted in Canada on rapidly draining soils present on steep south and west facing slopes, and on dryer sites with exposed bedrock and periodic fires (Erickson, 1993). Prior to European settlement ca. 150 years ago First Nations people harvested plants (e.g. Camassia quamash and Allium acuminatum) and deer (Odocoileus hemionus) from Garry oak savannas. To help maintain these valuable resources they periodically burned them to prevent encroachment from conifers and to promote food and forage species (Turner, 1999). Today, less then 5% of pre-European Garry oak savannas remain in British Columbia. This is primarily due to historical and recent urban and agricultural development. Furthermore, Garry oak ecosystems are threatened by invasive species that are believed to out-compete native taxa (Erickson, 1993). Approximately 100 plant and animal species are “at risk” in these systems, including 23 species that have been designated as threatened or endangered throughout their global range (GOERT, 2006). Given that the future of these ecosystems in Canada are in jeopardy, many community and scientific organizations are involved in conservation efforts. Some of these efforts involve protection from cattle grazing and reintroducing native species to meadows that have lost some of their original compliment of species. Garry oak ecosystems exhibit higher levels of biodiversity than most other ecosystems in western Canada (MacDougall, 2004). Biodiversity can be viewed as the variety of information contained in any biological community (Noss, 1990). For example, a population of a given species with high allelic variation would have high genetic biodiversity; a species with many subspecies would have high species biodiversity; and an ecosystem with a great variety of species represented would have high ecosystem biodiversity. Our brief ecological survey investigated one aspect of this latter type of biodiversity relating to changes in the overall patterns of distribution and abundance of six plant species that are characteristic of Garry oak communities.
Davidsonia 17:3 89 Photo: Esson et al. Figure 1. Sample site 1 at Somenos Garry Oak Protected Area, April 26 th , 2005. The general purpose of our study was to assess the extent to which Garry oak systems were influenced by agriculture and urban development by comparing a heavily disturbed site to a site that had been placed under protection and had a rehabilitation program in place. Specifically, we addressed the following two questions: (1) did the quantitative occurrence of a representative group of six plant species differ significantly between the two sites, and (2) did the two sites differ in their biodiversity information as expressed through the patterns of assemblages among the six species METHODS In late April 2005, we conducted a vegetation survey at two Garry oak parkland sites, which we visited during a University of British Columbia Botany Graduate Field Course. Site 1 was in the Somenos Garry Oak Reserve, and was adjacent to a new housing development (Figure 1).
Page 1 and 2: Volume 17, Number 3 July 2006 David
Page 3 and 4: Davidsonia 17:3 73 Editorial This i
Page 5 and 6: Davidsonia 17:3 75 Viscin Cells in
Page 7 and 8: Davidsonia 17:3 77 xylose and gluco
Page 9 and 10: Davidsonia 17:3 79 Image: Cynthia M
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Page 15 and 16: Davidsonia 17:3 85 such activity in
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Page 21 and 22: Davidsonia 17:3 91 Photo: Esson et
Page 23 and 24: Davidsonia 17:3 93 Based on purely
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Page 27 and 28: Davidsonia 17:3 97 REFERENCES Allen
Page 29 and 30: Davidsonia 17:3 99 The next step, t
Page 31 and 32: Davidsonia 17:3 101 plant cuticles
Page 33 and 34: Davidsonia 17:3 103 Gleanings Notes
Page 35 and 36: Table of Contents Editorial Taylor

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