Lab 6 Coastal Sage Scrub - SCa

Lab 6 Coastal Sage Scrub - SCa - Group Name: Members...

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Group Name: Members Present: Lab 6: Coastal Sage Scrub Plant Community, Species Diversity, and Invasive Species (adapted from Lab 3: Coastal Sage Scrub Plant Community by Michael Fugate, PhD at UCR) I. Communities and Community Structure : A community is an association of interacting populations of species inhabiting some defined area. Based on competition, exploitative interactions (predation, disease, parasitism, etc.), and mutualisms, communities represent the biotic portion of an ecosystem that participate in energy flow and matter cycles. Community ecologists seek to understand how abiotic and biotic aspects of the environment influence the structure of communities. Community structure includes attributes such as the number of species, relative abundance of species, and kinds of species within a community. II. Our Local Community : The California Coastal Sage Scrub and Chaparral ecoregion ranges from northern Baja California, Mexico to coastal southern California and extends eastward to the Colorado (a.k.a. Sonoran) Desert and southward to Punta Baja, Mexico. The landscape is flat to foothills and is only 1 of 5 Mediterranean-climate ecoregions in the world. The winters are cool and wet, but the summers are hot and dry. Annual average rainfall is low, between 150 and 500mm (Dallman, 1998 www.worldwildlife.org ). Coastal Sage Scrub (CSS) has dense stands of typically drought-deciduous subshrubs (0.5-2m in height). Dominant plants in the Riverside area historically included California sagebrush ( Artemisia californica ) and brittlebush ( Encelia farinosa ). Other native shrub species include California buckwheat ( Eriogonum fasiculatum ), Black sage ( Salvia mellifera ), White sage ( Salvia apiana ) and Purple nightshade ( Solanum xantii ). Encelia tends to favor and dominate south and east facing slopes while the others north and west facing slopes. Within the last 2-3 decades, non-native annual grasses invaded CSS communities in southern California and replaced many native species found on north-facing slopes. In their native habitat, these species ( Bromus diandrus , Bromus madritensis , and Avena barbata ) are found only in recently disturbed areas and are replaced by perennial forbs and shrubs. In California, they also invade disturbed areas, but replacement by native flora is often delayed indefinitely. 1. What sort of climate do you think the non-native grasses evolved in? 2. Given the very hot and dry summers along with human ignition sources (cars, cigarettes, etc.), what sort of disturbance do you think might be common to our area? Would this potentially contribute to the establishment of non-native grasses? Several factors may contribute to the success of the non-native grasses in our area including life history
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Lab 6 Coastal Sage Scrub - SCa - Group Name: Members...

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