Diego’s research on scaling metabolism from individuals to reef-fish communities won the first prize for ‘best student presentation‘ at the The International Biogeography Society Early Career Conference 2014 in Canberra.
As fish disperse to find new habitats, scientists have developed a new model to judge a species’ success in colonising new places. The study, published this week on PNAS (open access), has shown some surprising results, suggesting that success can best be determined in the traits of adult individuals, and not in a species’ larval stages, as previously thought.
“The more places a tropical fish species lives,” says lead author Osmar Luiz, “the less it is endangered to extinction. It is important, then, to identify exactly which features of a species can best determine the scope of their distribution across the oceans, so we can more accurately predict and identify endangered species.”
Marine organisms disperse mostly by ocean currents as larvae. Until now, it has been thought that species with longer larval periods can disperse further, and achieve larger geographic distribution across the oceans – thus having a lower chance of extinction.
However, Luiz and team found that, instead of this larval stage, there are some specific adult characteristics of species that can better predict distribution size among these species. He points to the colonization success, of when new populations build up in a new area, as a better determinant of ongoing species safety.
“Our study warns that predictions of species dispersal potential based on the variability in they larval stage are misleading, and we indicate three other adult characteristics that relates to dispersal ability and should be used in such analysis.”
“Very counter intuitively, these characteristics manifest while fishes are adults, so we were until now looking into the wrong life-stage,” says Luiz.
These characteristics are schooling, nocturnal activity, and large size. These three characteristics emerged across different oceans despite interregional differences in habitat geography.
The comprehensive study used the largest dataset in analysis of this type, collecting data for 590 species, across three different oceans. Luiz and his supervisor Joshua Madin have been exploring the dispersal patterns of tropical fish for some time, both globally and in Australia.
The Coral Trait Database is a growing compilation of scleractinian coral life history trait, phylogenetic and biogeographic data. The database was initially a series of spreadsheet tables, but starting in 2013 this data is being transitioned into an online collaborative database with a growing number of contributors.
As of August 2013, there were 78318 trait entries (observations) for 1555 coral species in the database. Most of these trait entries are for shallow-water, reef-building species. Data contributors have access control over the data they enter. Nonetheless, an increasing proportion of these data is publicly accessible.
In findings published today in the Marine Ecology Progress Series, researchers have found that ocean currents may explain why the Indo-Pacific lionfish Pterois volitans living in the Atlantic is yet to make its way to Brazil.
Osmar Luiz, from Macquarie University, and collaborators have investigated migration patterns of reef fishes in the area, and found that vagrant species migrations are more common in the direction of the North Brazil Current, which flows from Brazil towards the Caribbean than the reverse.
“Knowing that the species demonstrates infrequent migration against the currents may slow the pace of the potential invasion, which could help eradication programs in Brazil,” says researcher Osmar Luiz.
Since its introduction to the northwestern Atlantic, around 15 years ago, the species has rapidly spread through the Greater Caribbean. Though it is predicted they will extend their range throughout most of the eastern coast of South America, they are yet to be recorded in Brazil.
Researcher do warn though currents may slow their migration, the lionfish has a suite of traits that would eventually lead it over that barrier and so these areas are still at risk.
“These results show there is still uncertainty in the scenarios that could emerge from the lionfish invasion in the Brazilian Province, and precautionary actions are recommend,” says Luiz.