Dear list,
We are carrying on a study to evaluate the effects of trampling on the
abundance/diversity/distribution of pioneer vegetation in a natural
beach. The extent of the area sampled is quite narrow: 1650 m length and
6 m width. We've sampled vegetation in May (pre-tourism season) and in
September (post-tourism season), taking each month 500 random 1m2
samples (different ones for each season). There are 3 areas where
trampling is excluded. We want to evaluate interaction between protected
areas and season.
We have proposed the following steps to analyse the dataset:
1. Model selection. We have generated a previous GLM for each season
with the explanatory variables (excluding protection to be able to
analyse it a posteriori). Due to autocorrelated nature of response and
explanatory variables, we have proposed to perform model selection by
means of Conditional Gaussian Random Fields.
2. Protection analysis. As variography of the residuals from the
selected model results with a range of 40m, we have proposed to group
them in blocks of 25mx6m separated by at least 50m. Each block
constitutes a fully protected or unprotected area. Then, we would test
interaction between protection and season by means of conventional
statistics.
Any help appreciated, maybe also some references to relevant articles.
Thank`s a lot
Regards
--
David March Morlà
Doctorando / PhD student
Instituto Mediterraneo de Estudios Avanzados (UIB-CSIC)
C/Miquel Marqués, 21
07190 Esporles
Islas Baleares - Spain
Tel: +34 971 611 722
Fax: +34 971 611 761
Email: [EMAIL PROTECTED]
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