Highly disturbed populations of seagrass show increased resilience but lower genotypic diversity

Connolly, Rod M., Smith, Timothy M., Maxwell, Paul S., Olds, Andrew D., Macreadie, Peter I., and Sherman, Craig D.H. (2018) Highly disturbed populations of seagrass show increased resilience but lower genotypic diversity. Frontiers in Plant Science, 9. 894.

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The response of seagrass systems to a severe disturbance provides an opportunity to quantify the degree of resilience in different meadows, and subsequently to test whether there is a genetic basis to resilience. We used existing data on levels of long-standing disturbance from poor water quality, and the responses of seagrass (Zostera muelleri) after an extreme flood event in Moreton Bay, Queensland, Australia. Sites were grouped into high and low disturbance categories, in which seagrass showed high and low resilience, respectively, as determined by measuring rates of key feedback processes (nutrient removal, suppression of sediment resuspension, and algal grazing), and physiological and morphological traits. Theoretically, meadows with higher genotypic diversity would be expected to have greater resilience. However, because the more resilient meadows occur in areas historically exposed to high disturbance, the alternative is also possible, that selection will have resulted in a narrower, less diverse subset of genotypes than in less disturbed meadows. Levels of genotypic and genetic diversity (allelic richness) based on 11 microsatellite loci, were positively related (R2 = 0.58). Genotypic diversity was significantly lower at highly disturbed sites (R = 0.49) than at less disturbed sites (R = 0.61). Genotypic diversity also showed a negative trend with two morphological characteristics known to confer resilience on seagrass in Moreton Bay, leaf chlorophyll concentrations and seagrass biomass. Genetic diversity did not differ between disturbed and undisturbed sites. We postulate that the explanation for these results is historical selection for genotypes that confer protection against disturbance, reducing diversity in meadows that contemporarily show greater resilience.

Item ID: 74908
Item Type: Article (Research - C1)
ISSN: 1664-462X
Keywords: Disturbance, Genotypic diversity, Resilience, Seagrass, Zostera muelleri
Copyright Information: Copyright © 2018 Connolly, Smith, Maxwell, Olds, Macreadie and Sherman. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Date Deposited: 22 Aug 2022 02:25
FoR Codes: 31 BIOLOGICAL SCIENCES > 3103 Ecology > 310305 Marine and estuarine ecology (incl. marine ichthyology) @ 70%
31 BIOLOGICAL SCIENCES > 3108 Plant biology > 310804 Plant developmental and reproductive biology @ 30%
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