Is there a complete loss of genetic diversity for the Thalassia testudinum populations at the species margin in Florida's coastal waters?
   Brad Peterson, Stony Brook University

Abstract: A recent investigation of Thalassia testudinum (tutlegrass) populations within the northern Indian River Lagoon (IRL) found that the genetic diversity was extremely low, perhaps zero. Remarkably, only a single genotype was present over a 9 km stretch of IRL. This has enormous implications regarding the ability of these seagrass beds at the northern extent of their range to adapt to changing environmental parameters or disease. We propose to quantify the extent of this lack of genetic diversity in IRL and determine if the same pattern exists at the species margin on the western coast of Florida as well. The primary objective of this proposal is to determine the susceptibility to catastrophic loss of Thalassia testudinum populations occurring at the species margins on Florida’s eastern and western coasts. Specific goals to reach this objective are: 1. Establish if Thalassia beds to the north of the single genotype observed in Indian River Lagoon are composed exclusively of the same genetically unique individual. 2. Quantify if genetic diversity increases in Indian River Lagoon populations south of the areas already sampled. 3. Determine if the Thalassia populations along the species’ margin on the west coast of Florida are characterized by a similar lack of genetic diversity. 4. Estimate how much of the observed lack of genetic diversity can be apportioned to environmental stress, biological limits, anthropogenic influences, or geologic segregation 5. Provide coastal resource managers with information critical for determining and prioritizing Thalassia populations and regions at greatest risk of catastrophic loss. This project will produce unambiguous evidence about the genetic diversity of species-margin populations of an important seagrass species. Data about the genetic diversity, spatial structure, population structure, sexual reproduction estimates, and estimates of recruitment will be critical in assessing the potential for this species to persist under changing environmental conditions. The data collected in this project will allow resource managers to assess the susceptibility of these populations to local extinction and determine the suitability of restoration efforts in these areas.

Award Matching Funds Total
$97,705.00 $97,705.00 $195,410.00

Year Funded Starting Date Ending Date
2009 7/1/2010 6/30/2013

Location: Escambia, Franklin, Gulf, Indian River, Martin, Pinellas and St. Lucie Counties