Publisher :
Place of publication :
Publication year : 0
Thematic : Marine Resources
Language : English
Note
Aim
To determine whether the diversity of resident and transient coral-dwelling
fish responds differentially to gradients in regional species richness.
Location
Three regions in the Indo-Pacific (Red Sea, western Indian Ocean, Great
Barrier Reef) which contain increasingly larger regional diversities of reef fish.
Methods
I surveyed fish residing within branching coral species. Fish species
were a priori categorized as resident or transient based on the degree of affiliation
between the fish and live coral. To compare among regions that differ in coral
diversity I used a modified species–volume relationship (SVR). Each point in the
SVR represents the total number of fish species, resident or transient, found within
the cumulative volume of a specific coral species. Empirical SVRs were further
compared with random-placement null models.
Results
For transient species, I found that the observed SVRs did not differ consistently
from those expected from random samples drawn from the corresponding
regional species pools. In addition, for a given volume of coral, more fish species
were found in richer regions, indicating strong regional influences on local diversity.
In contrast, resident richness was lower than that expected from random samples of
the species pool, and richness in rich regions was reduced comparably more than in
poor regions. The SVRs of resident species were similar among regions with different
regional diversities.
Main conclusion
These results suggest that, within coral species, transient fish
richness is mostly influenced by stochastic allocation of species from the regional
pool. Conversely, richness of resident species within a coral species is limited,
making it independent of regional diversity. Since higher regional diversity of
resident fish was not accompanied by higher richness per coral species or by decreased
niche breadth, higher regional diversity of resident fish species must be rooted in
higher coral richness. Consequently, ecological interactions between functional
groups (coral and fish) can be powerful drivers of regional biodiversity.
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Keywords : Vernaya fulva
Encoded by : Pauline Carmel Joy Eje
