Disturbance and Invasion in Coastal Sage Scrub PDF Download

Author: Genie M. Fleming
Publisher:
ISBN:
Category :
Languages : en
Pages : 186

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Author: Kyra R. Engelberg
Publisher:
ISBN: 9781124607245
Category : Sagebrush
Languages : en
Pages : 192

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Abstract: Coastal sage scrub (CSS) is a unique and highly threatened vegetation community in coastal Southern California and northern Mexico, with 90 percent lost to development, agriculture, and invasive species. Understanding CSS recovery is critical to its survival. This study looks at the long-term effects of grazing and cultivation in southern California by tracking the extent of exotic grassland in two valleys in the Santa Monica Mountains over sixty years. The rates of native shrub return in a grazed valley were compared to those in a cultivated valley. Transects compared physical differences of stable and recovering grassland-shrubland boundaries. Native shrubs returned to the grass valley that was grazed nearly one and one-half times faster than the valley that was cultivated. Cultivation may result in a type conversion of CSS to a new steady state of exotic annual grassland. The field transects showed that stable and recovering boundaries had different physical characteristics.

Author: Francisca Dinora Herrera
Publisher:
ISBN:
Category : Soil seed banks
Languages : en
Pages : 224

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Author: Celeste Wilson
Publisher:
ISBN:
Category : Ice plant
Languages : en
Pages : 284

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The results of this study demostrated that, if Carpobrotus edulis is exterminated, indigenous species, specifically Baccharis pilularis, will replace it under certain environmental conditions.

Author: Claire Elizabeth Wainwright
Publisher:
ISBN: 9781124540108
Category :
Languages : en
Pages : 31

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Exotic annual grasses are invading native plant communities in many areas including the western United States, and pose a significant challenge to habitat restoration. Observations in California grasslands suggest that exotic species may become active earlier in the growing season than native species, and that this distinct phenology may contribute to invasion success. We hypothesized that flexible germination cues may allow exotic annual grasses to start annual growth early each growing season and preempt resources prior to native seedling establishment, a kind of seasonal priority effect. Flexible germination cues could incur a cost, however, if they cause seeds to germinate before the onset of favorable growing conditions. To evaluate these predictions, we compared native and exotic species performance in a coastal sage scrub community under both early (off-season) and ambient (natural) rainfall timings. Exotic annual grasses germinated substantially with off-season watering, but none of the early seedlings survived until the onset of the natural rains. Exotic annual grasses that experienced off-season watering had a depleted seedbank and lower germination following the natural rains. In contrast, native species did not germinate following the off-season watering pulse, and instead emerged with the beginning of the cold natural rains. Our results suggest that phenology is an important factor influencing invasion success and invader impact. Under some conditions, pre-growing season watering could be an important restoration strategy for native plant communities in early stages of invasion by depleting the exotic seedbank and allowing for native species to establish with reduced competition.

Author: Wendy Dunbarr
Publisher:
ISBN:
Category :
Languages : en
Pages : 66

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Non-native invasive plants threaten native plants in ecosystems through competition for resources, alteration to ecosystem functions and disturbance regimes, and changes to food webs and mutualistic relationships. Decades of intense disturbance and fragmentation of coastal sage scrub in Southern California have led to type conversion from mixed native shrub cover to non-native annual grassland in many places. Restoration efforts have been carried out by various government and private land managers in an effort to preserve existing coastal sage scrub and create additional habitat. Ecological restoration typically focuses on vegetation for both restoration activities and assessments of project outcomes. Additional measures of ecosystem function should be considered when evaluating the progress of restoration projects. Terrestrial arthropods occupy a wide breadth of niches and provide valuable ecosystem services (seed dispersal, x decomposition, food sources for higher trophic levels). They are also sensitive to subtle, small-scale changes in the environment, which makes them more likely to be restored before larger animals. This study compared terrestrial arthropod assemblages along with vegetation characteristics among three types of sites (invaded, restored, native) to evaluate the success of two coastal sage scrub restoration projects within the Santa Monica Mountains National Recreation Area. Terrestrial arthropod assemblage compositions were successfully restored at both canyons. These results agreed with vegetation results at Cheeseboro Canyon, but contradicted vegetation results at Zuma Canyon. The results of this study indicate that restoration projects at both canyons were successful. The successful restoration of arthropod assemblage compositions despite spatial isolation and vegetative differences of the restored areas supported the Field of Dreams hypothesis that “if you build it, they will come”. The addition of terrestrial arthropod data to the standard practice of vegetation monitoring provided a more thorough evaluation of the status of these restoration projects, and should be used by land managers in the future.

Author: Harold Mooney
Publisher: Univ of California Press
ISBN: 0520278801
Category : Nature
Languages : en
Pages : 1008

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This long-anticipated reference and sourcebook for CaliforniaÕs remarkable ecological abundance provides an integrated assessment of each major ecosystem typeÑits distribution, structure, function, and management. A comprehensive synthesis of our knowledge about this biologically diverse state, Ecosystems of California covers the state from oceans to mountaintops using multiple lenses: past and present, flora and fauna, aquatic and terrestrial, natural and managed. Each chapter evaluates natural processes for a specific ecosystem, describes drivers of change, and discusses how that ecosystem may be altered in the future. This book also explores the drivers of CaliforniaÕs ecological patterns and the history of the stateÕs various ecosystems, outlining how the challenges of climate change and invasive species and opportunities for regulation and stewardship could potentially affect the stateÕs ecosystems. The text explicitly incorporates both human impacts and conservation and restoration efforts and shows how ecosystems support human well-being. Edited by two esteemed ecosystem ecologists and with overviews by leading experts on each ecosystem, this definitive work will be indispensable for natural resource management and conservation professionals as well as for undergraduate or graduate students of CaliforniaÕs environment and curious naturalists.

Author: Shannon M. Kirshtner
Publisher:
ISBN:
Category : Ants
Languages : en
Pages : 174

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Author: Spring Larine Strahm
Publisher:
ISBN:
Category :
Languages : en
Pages : 180

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Author: Michael Barbour
Publisher: Univ of California Press
ISBN: 0520249550
Category : Nature
Languages : en
Pages : 732

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Book Description
"This completely new edition of Terrestrial Vegetation of California clearly documents the extraordinary complexity and richness of the plant communities and of the state and the forces that shape them. This volume is a storehouse of information of value to anyone concerned with meeting the challenge of understanding, managing or conserving these unique plant communities under the growing threats of climate change, biological invasions and development."—Harold Mooney, Professor of Environmental Biology, Stanford University "The plants of California are under threat like never before. Traditional pressures of development and invasive species have been joined by a newly-recognized threat: human-caused climate change. It is essential that we thoroughly understand current plant community dynamics in order to have a hope of conserving them. This book represents an important, well-timed advance in knowledge of the vegetation of this diverse state and is an essential resource for professionals, students, and the general public alike."—Brent Mishler, Director of the University & Jepson Herbaria and Professor of Integrative Biology, University of California, Berkeley