Some detailed biogeographical/macroecological patterns - Nonequilibrium Ecology - page 142

Figure 9.2. Geographical patterns in reef fish diversity in the Indo-Pacific oceans.
Richness is far greater in the center than in outlying regions. IPR - Indonesian/
Philippine region. a, b, clines (solid lines) defined as the number of species whose
geographical ranges include a point in latitude or longitude, respectively. c, d,
distributions of mid-latitudinal or mid-longitudinal ranges (bars). Effects of the
mid-domain effect were tested by running a null-model (for details see Mora et al.
2003 ); dotted lines correspond to the maximum and minimum values after running
the model. The result shows that the great species richness in the center cannot be
explained by a mid-domain effect. Reprinted fromMora, Chittaro, Sale, Kritzer, and
Ludsin ( 2003 ), with the permission of MacMillan Publishing Ltd., and the authors.
Reef fishes: geographical distribution is determined by a center
of diversity and dispersal from it
Mora et al.( 2003 ) examined the distribution of 1970 species of Indo-Pacific
reef fishes (more than 70% of all the species expected in any reef fish
community) from 70 locations, demonstrating a center of high diversity
in the Indonesian and Philippine regions. Species numbers decreased
steadily along latitudinal and longitudinal axes away from this center
(Figure 9.2 ) . Although superficially similar to a distribution resulting from
a mid-domain effect, the observed nonrandom distribution with the very
high species numbers in the center cannot be explained by such an effect.
Threehypothesestoexplainthelarge-scalepatterninreeffishdistribu-
tion have been proposed, i.e., the center-of-origin hypothesis (the center is a