Dear friends,
I would like to know your opinion on an analytical issue I am
facing.
I am evaluating whether the main ideas found in the ecological
literature regarding forest succession in tropical regions (a large part
of which written or influenced by you) apply to intensively-logged
subtropical mixed forests in southern Brazil.
As some authors (Norden et al. 2009 is the most recent example), we
also have plots of adult trees with subsamples of poles and saplings
samples in subplots nested within the larger plots.
When it comes to the calculation of compositional similarities between
plots and across size classes through both NMDS ordinations and
similarity indexes (e.g. the Chao-Jaccard), however, an important doubt
arises:
How to procceed with these calculations if size classes were sampled
with different sample areas? I am inclined to simply use relativized or
standardized abundances as input to Chao-Jaccard similarities and to
NMDS. A second alternative would be to extrapolate species-specific
abundances of poles and saplings to the scale of larger plots.
How wouuld you handle with this problem?
Thank you in advance for your attention,
Best whishes,
Alexandre
Dr. Alexandre F. Souza
Programa de Pós-Graduação em Biologia: Diversidade e Manejo da Vida
Silvestre
Universidade do Vale do Rio dos Sinos (UNISINOS)
Av. UNISINOS 950 - C.P. 275, São Leopoldo 93022-000, RS - Brasil
Telefone: (051)3590-8477 ramal 1263
Skype: alexfadigas
[email protected]
http://www.unisinos.br/laboratorios/lecopop
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