11th ICRS Abstract book - Nova Southeastern University

Oral Mini-Symposium 26: Biodiversity and Diversification of Reef Organisms
26-17
Commonness, Rarity, And Biodiversity On Indo-Pacific Coral Reefs
Sean CONNOLLY* 1,2 , Maria DORNELAS 2,3 , Terry HUGHES 2 , David BELLWOOD 1,2
1 School of Marine and Tropical Biology, James Cook University, Townsville, QLD,
Australia, 2 ARC Centre of Excellence for Coral Reef Studies, James Cook University,
Townsville, QLD, Australia, 3 Gatty Marine Laboratory, University of St Andrews, St
Andrews, Fife, United Kingdom
Patterns in the commonness and rarity of species are a fundamental characteristic of
ecological assemblages, and are frequently used to test alternative models of biodiversity.
However, attempts to test between alternative models for such patterns often lead to
inconclusive results, leading to calls for a greater diversity of approaches to testing
species-abundance models. Here, we examine patterns of commonness and rarity in
tropical reef fishes and corals from a 10,000-km transect across the Pacific Ocean, and
we assess their concordance with species-abundance models based on lognormal, gamma,
and neutral model distributions. To overcome problems with previous analyses, we
develop a new goodness-of-fit test that explicitly treats individuals, rather than species, as
the units that are sampled. We find that the lognormal provides substantially better fit to
patterns of commonness and rarity than the alternatives, deviates from the data by less
than 1%, on average, and produces far better estimates of metacommunity diversity than
the alternatives. Neutral and gamma-based alternatives perform poorly because our data
exhibit a combination of many very rare species and a few highly abundant species,
which these models cannot simultaneously capture. It is likely that interspecific
differences, such as those implicit in models generating lognormal distributions, will be
required to explain this kind of heterogeneity in species abundances.
26-18
Coral Species Abundance Distribution: Patterns Of Commonness And Rarity
Maria DORNELAS* 1 , Sean CONNOLLY 1
1 ARC Centre of Excellence for Coral Reef Studies, Townsville, Australia
Species abundance distributions portray the patterns of species rarity and commonness in
ecological communities, and therefore are important measures of biodiversity. However,
the abundances of rare species, which are often particularly important for conservation,
require large samples to be confidently estimated. Here, we present the species
abundance distribution for a sample of >40,000 coral colonies from a single bay in Lizard
Island. This exceeds existing samples of coral assemblages by over an order of
magnitude. Although species abundance distributions are widely accepted to follow a
lognormal distribution, our data have a multimodal distribution. Three different model
selection procedures all indicate that the underlying community abundance distribution
has at least three modes. Thus, the multiple modes in our data are a real feature of
community abundance distributions, rather than stochastic sampling effects. We
hypothesize that this pattern may be caused by variability in species spatial distributions.
26-19
The Stability Of Clonal Lineages Over Space And Time
Daniel PETTAY* 1 , Todd LAJEUNESSE 1 , Dustin KEMP 2
1 Pennsylvania State University, University Park, PA, 2 University of Georgia, Athens, GA
Recent use of molecular techniques has revealed that the dinoflagellate genus Symbiodinium,
once believed to be one pandemic species, includes many highly divergent clades, each
containing numerous species or “types” (based on rDNA ITS1 & 2 fingerpinting). While much
research has been conducted to determine the specificity between host and symbiont, little is
known about the clonality of a particular symbiont “type” over a single colony and within a
colony over time. To examine the clonal diversity of clade B types over space and time, nine
polymorphic microsatellite loci were amplified and sequenced to yield a multilocus genotype.
While certain host and symbiont taxa appear to be more flexible in their ability to associate with
numerous partners, a majority of the data indicate strong specificity between host and symbiont.
Even the Caribbean coral Montastrea faveolata, which can associate with symbionts
belonging to clades A through D, shows specificity for only a small subset of subcladal types
that correlate with both bathymetry and geography. Hosts like the coral Meadrina
meandrites epitomize this specificity by associating with only one ITS2 type throughout the
Caribbean. Analyzing samples collected from hosts like the two described above enable
comparisons to be made between both symbioses which appear to be more flexible and
symbioses which are quite specific. Host species known to display a range of specificity (i.e.
low specificity = M. faveolata, high specificity = M. meandrites) were sampled repeatedly
to determine clonal diversity spatially. To examine the longevity of clonal lineages, a subset of
colonies were also sampled seasonally. To date, the data indicate that a majority of the colonies
host a single symbiont lineage over the entire colony. Continued research in this area will also
allow species boundaries to be determined and provide insight into the evolutionary processes
of Symbiodinium.
26-20
Diversity Dynamics Of Reefs And Level-Bottom Communities Compared: Paleontological
Evidence For Reefs As Sources Of Biodiversity Over The Last 240 Myr
Wolfgang KIESSLING* 1
1 Museum of Natural History, Humboldt University, Berlin, Germany
The fossil record of Mesozoic-Cenozoic reefs is used to evaluate the role of evolutionary origin
versus ecological maintenance in the biodiversity of living and ancient reefs. Data from the
Paleobiology Database (http://paleodb.org) were analyzed to compare the diversity dynamics of
taxa with a statistically significant preference for reefs with those having a preference for nonreef
marine habitats.
After standardizing for different sample sizes (reef data are more limited than other data) the
results suggest that reefs have significantly greater rates of speciation than level-bottom
communities. Except for mass extinction episodes, in which reef taxa are more substantially
affected than level-bottom taxa, there is no evidence for generally greater or smaller extinction
rates of reef taxa. Therefore reefs can be viewed as cradles of evolution over long stretches of
time, whereas there is no evidence for reefs preserving diversity better than other ecosystems.
Although these results strictly apply to only those taxa that are readily fossilized (corals,
hypercalcified sponges, bivalves, gastropods, echinoderms and brachiopods), there is no reason
to assume that other taxa should not follow the same basic trends.
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