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Activity Number:
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377
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Type:
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Contributed
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Date/Time:
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Wednesday, August 9, 2006 : 8:30 AM to 10:20 AM
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Sponsor:
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Biometrics Section
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| Abstract - #305544 |
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Title:
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Assessing Similarity of Two Assemblages with Unseen Species in Samples
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Author(s):
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Tsung-Jen Shen*+ and Anne Chao and Robin L. Chazdon and Robert L. Colwell
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Companies:
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National Chung Hsing University and National Tsing Hua University and University of Connecticut and University of Connecticut
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Address:
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250 Kuo Kwang Road, TaiChung, 405, Taiwan
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Keywords:
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beta diversity ; biodiversity ; forest succession ; species overlap
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Abstract:
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A variety of similarity indexes for comparing two assemblages based on species incidence data have been proposed in the literature. These indexes are generally in terms of two simple incidence counts: the number of species shared by two assemblages and the number of species unique to each. We provide a new, probabilistic derivation for any incidence-based index that is symmetric and homogeneous. The probabilistic approach is further extended to formulate abundance-based indexes. Thus, any symmetric and homogeneous incidence index can be modified easily to an abundance-type version. Applying the Laplace approximation formulas, the proposed estimators that adjust for the effect of unseen shared species on our abundance-based indexes will be presented. Data on successional vegetation in six tropical forests are used for illustration.
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