@ARTICLE {McGill2003a,
AUTHOR = {McGill, B.J.},
TITLE = {Does Mother Nature really prefer rare species or are log-left-skewed
SADs a sampling artefact?},
JOURNAL = {Ecology Letters},
YEAR = {2003},
VOLUME = {6},
PAGES = {766-773},
NUMBER = {8},
MONTH = {aug},
ABSTRACT = {Intensively sampled species abundance distributions (SADs) show left-skew
on a log scale. That is, there are too many rare species to fit
a lognormal distribution. I propose that this log-left-skew might
be a sampling artefact. Monte Carlo simulations show that taking
progressively larger samples from a log-unskewed distribution (such
as the lognormal) causes log-skew to decrease asymptotically (move
towards -infinity) until it reaches the level of the underlying
distribution (zero in this case). In contrast, accumulating certain
types of repeated small samples results in a log-skew that becomes
progressively more log-left-skewed to a level well beyond the underlying
distribution. These repeated samples correspond to samples from
the same site over many years or from many sites in 1 year. Data
from empirical datasets show that log-skew generally goes from
positive (right-skewed) to negative (left-skewed) as the number
of temporally or spatially replicated samples increases. This suggests
caution when interpreting log-left-skew as a pattern that needs
biological interpretation.},
OWNER = {brugerolles},
TIMESTAMP = {2007.12.18},
}