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Emergent patterns of genetic diversity across the Indo-Pacific Ocean, Libby Liggins [et al.]

Emergent patterns of genetic diversity across the Indo-Pacific Ocean, Libby Liggins [et al.]

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thermore, regions where genetic diversity and species diversity diverge are identified, providing

insight into the processes generating diversity patterns across the biodiversity hierarchy.



111



Environmental drivers of Pomacentridae

distribution and abundance in American

Samoa

Motusaga Vaeoso

1



∗ 1



American Samoa Department of Marine and Wildlife Resources – PO Box 3730, Pago Pago, 96799.,

American Samoa



Currently, no detailed ecological analyses of Pomacentridae species have been conducted in

American Samoa. There is a local resource management need to improve coral reef monitoring

methods to incorporate rapid assessment techniques, including the use of indicator species responsive to changes in local coral reef ecosystems. This study focusses on initial investigations

into the linkages between Pomacentrid damselfish community composition, benthic habitat composition, specific coral species, and local environmental variables. In 2015 a US-EPA funded

project was developed between local resources agencies to increase the understanding of the linkages between water quality and coral reef health. Additional project goals included identifying

the most likely drivers of poor reef health, and how to address spatially different management

priorities around the main island of Tutuila. As part of this project, thirty reef slope sites were

surveyed over a three-week period in November 2016 around Tutuila Island, which included a

comprehensive survey of damselfish conducted by one surveyor. Sites were selected based on a

human population density gradient, and all sites were located at the same distance from major

stream mouths. Recent studies on trophic level and functional group categorization were incorporated into analysis on trends in trophic feeding groups. Using univariate and multivariate

statistical methods, initial investigations were conducted to determine whether the distribution

and abundance of different functional groups are driven by habitat composition, using benthic

cover data derived from photo-quadrat surveys and analyzed by CPCe. Environmental variables

were derived using GIS data layers to develop proxies for natural environmental factors and human stressors. When considering these environmental variables, there were no clear relationships

between the distribution and abundance of the most common Pomacentrid species. Additional

analysis relating trends in species composition between sites, showed predictable correlations

with benthic cover data and coral species demography data. This initial investigation into the

comprehensive Pomacentrid species data set will be complemented with future studies to incorporate NOAA CREP data, in addition to exploring potential temporal changes in community

composition and abundances following past disturbance events.







Speaker



112



Evolutionary processes underlying reef fish

latitudinal differences in biodiversity

Alexandre Siqueira



∗† 1



, Luiz Oliveira-Santos 2 , Peter Cowman 3 , Sergio

Floeter 4



1



College of Science and Engineering/Center of Excellence for Coral Reef Studies, James Cook

University (JCU) – Townsville, QLD, 4810, Australia

2

Departamento de Ecologia, Universidade Federal do Mato Grosso do Sul (UFMS) – Campo Grande,

MS, 79070-900, Brazil

3

Center of Excellence for Coral Reef Studies, James Cook University (JCU) – Townsville, QLD, 4810,

Australia

4

Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina (UFSC) –

Florian´

opolis, SC, 88040-970, Brazil



Although it has been described for many taxa and many hypotheses have been raised to

explain it, the latitudinal diversity gradient (LDG) remains poorly understood with respect to

its underlying processes. Part of this lack of understanding occurs because, for a long time,

historical and evolutionary factors have been overlooked as part of the explanation. Reef associated fishes make ideal candidates for the study of these evolutionary aspects since they reflect

a strong LDG with diversity distributed among tropical (coral reef) and extratropical (rocky

and algal reef) environments, and have relatively well resolved phylogenetic relationships. In

the present study, we examined the temporal dynamics of the processes of speciation, extinction and dispersal in the marine realm using phylogenies to reveal the evolutionary mechanisms

that promote latitudinal differences in biodiversity. Using phylogenetic comparative methods

we assessed whether tropical reef fish lineages show higher diversification rates and whether

the majority of extratropical lineages have originated from tropical areas. We used fossil calibrated phylogenies for four families (Chaetodontidae, Labridae, Pomacentridae and Sparidae)

and applied evolutionary models that allow the estimation of speciation, extinction and dispersal rates associated with geographic ranges. Further, we performed simulations to assess our

ability to distinguish between popular hypothesis for the LDG and explored potential biases

from unsampled characters. We found that tropical lineages show higher rates of speciation

and tended to have lower extinction rates. Overall, we identify higher net diversification rates

for tropical lineages compared with those in extratropical regions in all four families. Rates

of dispersal tended to be higher for lineages with tropical origins expanding into extratropical

regions. Within the family Labridae, two tropical lineages were found to exhibit higher net

diversification rates, above that expected from latitudinal differences. Our results offer support

for the predictions of the ‘out of the tropics’ and ‘evolutionary speed ’ models of evolution, both

of which highlight the marine tropics as an important evolutionary engine promoting latitudinal

differences in reef fish biodiversity. Moreover, we find that two tropical labrid lineages have

undergone exceptional diversification associated with additional traits, possibly linked with the

extreme sexual dichromatism observed in both clades.







Speaker

Corresponding author: alexandre.siqueira@my.jcu.edu.au



113



Further insight into the iterative ecological

radiation of damselfishes (Pomacentridae)

Laura Gajdzik 1 , Gilles Lepoint 2 , Loic Michel 2 , Nicolas Sturaro 2 , Eric

Parmentier 1 , David Lecchini 3 , Bruno Fr´ed´erich ∗ 1,2

1



Laboratory of Functional and Evolutionary Morphology, – AFFISH Research Center, University of

Li`ege, Li`ege, Belgium

2

Laboratory of Oceanology – MARE Centre, University of Li`ege, Li`ege, Belgium

3

Centre de recherches insulaires et observatoire de l’environnement (CRIOBE) – Universit´e de

Perpignan Via Domitia, Ecole Pratique des Hautes Etudes, Centre National de la Recherche

Scientifique : USR3278 – BP 1013 Papetoiai 98729 PAPETOAI, France



The evolutionary history of Pomacentridae (damselfishes) is a rare example of the occurrence of an iterative ecological radiation in the ocean. Damselfishes have experienced many

repeated convergences wherein subclades radiated across similar trophic strategies (i.e. pelagic

foragers, benthic feeders, and an intermediate group) and similar morphologies. The presence

of evolutionary convergences in damselfishes was recently highlighted by the combination of

ecological and morphological data, and the use of phylogenetic comparative methods. Nevertheless, many other aspects of these replicated sets of lineages remain unexplored. For example,

little is known about the functional diversity of assemblages including convergent lineages that

emerged from iterative processes of ecological radiation, or which of the niche-related processes

and phylogenetic conservatism are the major factors shaping these assemblages. Here, we conducted a quantitative comparison of these processes in damselfish assemblages that belong to

three distinct Indo-Pacific coral reefs differing in taxonomic composition, morphology and degree of human disturbance. Using various metrics, we compared the functional diversity (based

on a dataset of eight functional traits) and the isotopic diversity (a proxy of trophic diversity)

among assemblages, grasping many aspects of the eco-functional diversity of Pomacentridae. We

also tested whether these eco-functional traits displayed some evolutionary conservatism. Our

results demonstrate that the eco-functional diversity of damselfishes follows similar patterns

among Indo-Pacific coral reefs. The trophic space remains equivalent despite gradient in species

richness, whereas the number of functional entities occupied by taxa dictates the size of the

functional space. In each assemblage, eco-functional niches are highly differentiated and evenly

distributed in spaces of similar size. The inconsistent phylogenetic structure of eco-functional

traits suggests that the similarity in the diversity of damselfish assemblages is mainly driven by

niche-based processes and not by phylogenetic relatedness. We suggest that a broader application of our approach will help to uncover the mechanisms of reef fish community assembly over

space and time.







Speaker



114



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