Jorge A. Navarro Alberto & Bryan F.J. Manly 
Introduction to Ecological Sampling [PDF ebook] 

This book shows how to use sampling procedures for ecological and environmental studies. It incorporates both traditional sampling methods and recent developments in environmental and ecological sampling methods, including mark-recapture, adaptive, and removal sampling. The book explains the methods as simply as possible, keeping equations and their derivations to a minimum. Accessible to biologists, the text only assumes a basic knowledge of statistical methods. Data sets and R code are available on a supplementary website.