Connectivity: What is it? How is it measured? Why is it important for management?

Implications for Coral Reef Management

Until now, management of coral reefs, where it exists, has been reactive rather than proactive.  With coral reefs entering a time of even greater stress, it is essential that managers develop more proactive management approaches, with a strong basis on science.

Connectivity refers to the interconnection of marine populations through larval dispersal, which in turn influence the dynamics of each population.  At present there is very little information on levels of connectivity in coral reef regions, and management in Marine Protected Areas (MPA) depend too much on good luck and “guesstimates”.  

Through a number of projects, the CRTR Connectivity Working Group is determining connectivity patterns for selected species in the Mesoamerican region and developing and testing new methods to build a connectivity database.  

The use of connectivity information to accurately assess linkages among locations and local demographic capabilities will ensure future management programs are capable of sustaining coral reefs. 

Key questions

• What is Connectivity?
• How is it measured?
• Why is it important?

Research Update

CRTR Program Connectivity Working Group Research Update - October 2006 [download]

Key Achievements

The Connectivity Working Group has commenced several distinct, but interrelated projects in the Mesoamerican region.  These projects are intended to advance the science and demonstrate its effectiveness in terms of measuring the connectivity for particular kinds of species.  Projects and studies include:

• The Connectivity Working Group is working closely with local management agencies to build a database of recruitment of particular species at sites through the region, because recruitment data can inform us of the demographic rates of local populations, and can provide basic data needed for determining connectivity patterns.
• Studies of fish concern one typical species that does not aggregate over large distances to spawn, and one species that aggregates for spawning once a year.
• Studies of corals centre on technique development for tracking dispersing planula larvae and for identifying them to species.
• Genetic studies of coral populations are being used to discern likely connectivity patterns in the past.
• Studies of coral settlement and early survival are being done because this early benthic phase may be a critical bottleneck to coral success.
• Data is being collected on lobster recruitment, and on lobster larval biology for use in building models of larval dispersal. Validated models can provide information on connectivity among locations.  However, the spiny lobster has one of the longest larval lives of any reef species, so determining its connectivity patterns may be very difficult.