1 Macquarie University – Sydney, NSW 2109, Australia
2Universidade Federal de Santa Catarina – Campus Reitor Jo˜ao David Ferreira Lima, s/n - Trindade, Florian´opolis - SC, 88040-900, Brasil, Brazil
3 Universit´e de Montpellier – Institut de recherche pour le d´eveloppement [IRD] : UMR237, Centre National de la Recherche Scientifique - CNRS – 34095 Montpellier Cedex 5, France
4Universidade Federal de Santa Catarina – Campus Reitor Jo˜ao David Ferreira Lima, s/n - Trindade, Florian´opolis - SC, 88040-900, Brazil
Competition is a key process structuring ecological communities, as it affects individual survival and, ultimately, species distributions. Reef fish, contests for corals, algae and ben- thic invertebrates as shelter and food result in agonistic interactions that evidence direct intra- and inter-specific competition. However, the proximate and ultimate drivers of such aggres- sive behaviour remain underexplored. We hypothesize that high species density may stimulate competition, which may be fiercer among species that occupy similar functional roles in the com- munity. To test this, we investigate the influence of species abundance and functional similarity on the structure of reef fish agonistic interactions in three Indo-Pacific locations (Fiji, Bali, and Moorea). In each location, we recorded 50 remote (non-diver-operated) high-resolution video samples. Each video consisted of a 15-minute continuous shot of 2m2 of shallow sheltered reefs, from which we extracted the number agonistic interactions among fish species, and estimated the relative density of all species, observed interacting or not. We then built weighted networks to depict the interacting fish species as nodes connected by links whose thicknesses were pro- portional to their frequency of agonistic interactions. We also calculated functional traits and density distances among all interacting species. Using multiple regression quadratic assignment procedure (MRQAP), we tested whether such covariates affected the structure of the agonistic networks. Our findings reveal that neither functional proximity nor density explain the strength and distribution of agonistic interaction among fish. Conversely, the frequency of agonistic interactions was positively associated with overall density when considering both interacting and non-interacting species. The rate of increase in interactions with increasing overall density differed among locations, particularly at lower densities. Our findings indicate that reef fish agonistic behaviour is not solely driven by the density of interactig species neither by their func- tional similarity, although overall species density may play a role. Phylogenetic proximity may influence agonistic interactions due taxonomical conservation on species-pairs among networks,
Emergent patterns of genetic diversity across the Indo-Pacific Ocean
Libby Liggins ∗ 1,2, Eric Crandall 3, Cynthia Riginos 4, Michelle Gaither
5, Chris Bird 6, Sean Connolly 7, Loic Thibaut 8, Eric Treml 9, Elizabeth Sbrocco 10, Maria Beger 11, Peter Cowman 7, Rob Toonen 5, Diversity Of
The Indo-Pacific Network (dipnet) 12
1 Massey University – Auckland, New Zealand
2 Auckland War Memorial Museum – Auckland, New Zealand
3 California State University, Monterey Bay – United States
4The University of Queensland – Brisbane, Australia
5Hawai’i Institute of Marine Biology, University of Hawai’i at Manoa – Hawai’i, United States
6 Texas AM - Corpus Christi – Texas, United States
7 ARC Centre of Excellence for Coral Reef Studies, James Cook University – Townsville, Australia
8 James Cook University – Townsville, Australia
9University of Melbourne – Melbourne, Australia
10Ronin Institute – Montclair, New Jersey, United States
11 University of Leeds – Leeds, United Kingdom
12 http://diversityindopacific.net/ – Several countries, United States
Patterns of genetic diversity provide a window into the historical and contemporary de- mography of a focal species, and can inform their conservation management. However, despite the potential for genetic diversity information from a whole community of species to provide insight regarding the origin, maintenance, and future of that community, there have been few synthetic analyses of genetic diversity patterns across multiple species in the marine environ- ment. There is the general expectation that patterns of genetic diversity will mirror patterns of species diversity owing to common underlying drivers of biodiversity, such as habitat area (+), isolation (-), and stability/age of habitat (+), as suggested by the theory of island biogeography for species richness and Wright’s island model for genetic diversity. For instance, large areas of shallow reef habitat within the Indo-Australasian Archipelago – a well described species diver- sity hotspot – may also be expected to support large population sizes, and therefore high levels of genetic diversity. Although many researchers have independently collected genetic data for Indo-Pacific marine organisms over the past several decades, combining these data to address multi-species patterns of genetic diversity has been previously impeded by data accessibility and interoperability of database infrastructures. To overcome these challenges, the Diversity of the Indo-Pacific Network (DIPnet) was formed, and the Genomic Observatory Metadatabase (GeOMe) was established to provide a centralised repository for genetic data of marine species.
GeOMe is now the most extensive database of georeferenced mitochondrial DNA sequences com- prising over 35,000 individuals and over 200 species. In my talk I will present some of the first multi-species, synthetic analyses regarding genetic diversity patterns for Indo-Pacific marine or- ganisms, conducted by DIPnet and based on GeOMe data. Our analyses suggest that genetic diversity weakly correlates with patterns of species diversity in the Indo-Pacific Ocean. Fur-
∗Speaker
thermore, regions where genetic diversity and species diversity diverge are identified, providing insight into the processes generating diversity patterns across the biodiversity hierarchy.
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 re- sponsive to changes in local coral reef ecosystems. This study focusses on initial investigations into the linkages between Pomacentrid damselfish community composition, benthic habitat com- position, 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 link- ages 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 in- corporated 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 hu- man 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 incor- porate NOAA CREP data, in addition to exploring potential temporal changes in community composition and abundances following past disturbance events.
∗Speaker
Evolutionary processes underlying reef fish latitudinal differences in biodiversity
Alexandre Siqueira ∗† 1, Luiz Oliveira-Santos 2, Peter Cowman 3, Sergio Floeter 4
1College 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 asso- ciated 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, extinc- tion 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 cal- ibrated phylogenies for four families (Chaetodontidae, Labridae, Pomacentridae and Sparidae) and applied evolutionary models that allow the estimation of speciation, extinction and disper- sal 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
Further insight into the iterative ecological radiation of damselfishes (Pomacentridae)