Original Publication: 09/07/2012
Edited for grammar/syntax: 07/25/2019
The Coral Triangle is a biodiversity hotspot located in what is commonly considered to be the “East Indies,” but actually includes the following countries and their surrounding waters: Indonesia, Malaysia, Philipines, Brunei, Timor, Papua New Guinea, and the Solomon Islands. Despite it being a biodiversity hotspot, preservation management is limited, and so this area is also at great risk, particularly the reef and reef fish ecosystems. This article explores the origins of biodiversity in the Coral Triangle, assesses numerous case studies of biogeography carried out in the area, and examines the possibility of using concordant patterns of biogeography to inform management decisions.
The Coral Triangle is a unique area in that it is relatively young, geologically speaking, with high biodiversity shifting into this region from the Tethys Sea approximately 19 – 25 mya. The exact cause of pulses of biodiversity occurring in this region during that time is unknown, but studies suggest that plate tectonics played a roll, altering surface currents and isolating the region geographically at the same time. The article suggests that a combination of plate tectonics and surface currents shifting created an atmosphere of vicariance, that is, there is a high probability that extant species throughout the region and some ~19-25 mya were subject to vicariance events.
While the origin of biodiversity is still undergoing exploration, the patterns of invertebrate biogeography offer more concordant results between studies, with clear areas of vicariance appearing (e.g., the Sunda Shelf, a large suture zone). However, fish biogeography does not follow concordant patterns, suggesting differences in dispersal and life history affect the presence or absence of broad biographic patterns.
What are the benefits of observing these concordant patterns for ecological managers? In the case of the invertebrates, the identification of clear concordant patterns shows promise that biographic regions can be split up into management units, allowing managers to split their efforts into some small scale, targeted efforts along with some large scale, broader efforts. In other words, the use of these management units allows managers to become more effective at conserving biodiversity. However, studies in the Coral Triangle are still young (only within the last 10 years), and the full extent of biodiversity and potential concordant patterns have not been explored. The existence of highly divergent, and cryptic, mitochondrial lineages complicates things as morphology-based identification is already confounded by cryptic species. The Coral Triangle will likely allow for many more years of biogeographic study, and the addition of multi-loci genetic analysis will lend itself well to better understanding the biogeography of the area.