Species mean elevational range size pattern
Our study showed that the mean elevational range size pattern of
breeding birds in Lebu Valley was a hump-shaped pattern. It is worth
noting that there are several frequently used methods to describe
species mean range size patterns. McCain (2013) used the “Steven’s
method”, “midpoint method” and “quartile method” to explore the
relationships of species mean range size and elevation for vertebrates
from 160 mountains, and the results generated by these three methods
vary greatly (McCain & Knight, 2013). For example, the result by using
the Steven’s method showed that 40% of datasets found a positive
relationship between species mean range size and elevation. However,
only 0% and 38% of datasets found a positive relationship when using
the midpoint method and the quartile method. Our study conducted three
most commonly used methods to access the species mean elevational range
size pattern, and all approaches yield a consistent hump-shaped pattern
which indicated that our result was robust and unaffected by the
measuring methods. However, to compare the results of different studies,
we should use comparable methods to
access the elevational range size pattern across regions or taxa.