Kenneth S. Norris Rancho Marino Reserve

29 Jun, 03 AM - 29 Jun, 07 AM

Understanding why some exotic species flourish more than others and how they establish greater densities in their introduced ranges relative to their natives ranges are important issues for basic community ecology and the management of invasive species. Proposed hypotheses to explain successful establishment and spread of invasive species include advantages that invasive species experience in their introduced ranges, such as release from natural enemies, increased competitive ability, and increased colonization due to disturbance. Most research exploring these hypotheses has focused exclusively on communities into which invasive species have been introduced, however, we can attain a better understanding of processes underlying successful invasions by employing comparative studies of invasive species in their introduced and native ranges. Furthermore, species that are also invasive in their native range may provide a novel opportunity to examine the processes promoting invasibility by allowing comparisons between native non-weedy populations and weedy populations and populations invasive elsewhere. We will test three hypotheses for exotic plant invasions success:(i) escape from specialist insect herbivores, (ii) the evolution of increased competitive ability (EICA), and (iii) a greater response to disturbance in the introduced range using the South African native species Oxalis pes-caprae, a cosmopolitan weed in many parts of the world, including its native range in South Africa. These hypotheses will be tested using parallel manipulative experiments across distribution ranges in South Africa and USA, and by conducting reciprocal transplants between weedy and non-weedy populations within South Africa. We will experimentally manipulate insect herbivore pressure, interspecific competition , and create small-scale disturbances to determine how these factors affect the performance of Oxalis pes-caprae. Examining the role of these three factors in the invasion success of Oxalis pes-caprae can help develop management strategies that are specific in both its native range in South Africa as well as its introduced range elsewhere.

Visit #21907 @Kenneth S. Norris Rancho Marino Reserve

Approved

Under Project # 21997 | Research

Testing three hypotheses for the success of weedy Oxalis pes-caprae in the native and introduced range.

graduate_student - Cornell University

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Indrani Singh Jun 29, 2010 (1 days)

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Day Use Only 1 Jun 29 (4 hours)