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The Hawaiian freshwater algae biodiversity survey (2009-2014): systematic and biogeographic trends with an emphasis on the macroalgae.

Sherwood AR, Carlile AL, Neumann JM, Kociolek JP, Johansen JR, Lowe RL, Conklin KY, Presting GG - BMC Ecol. (2014)

Bottom Line: The Hawaiian freshwater algal biodiversity survey represents the first comprehensive effort to characterize the non-marine algae of a tropical region in the world using both morphological and molecular tools.Survey data were entered in the Hawaiian Freshwater Algal Database, which serves as a digital repository of photographs and micrographs, georeferenced localities and DNA sequence data.These analyses yielded an updated checklist of the non-marine macroalgae of the Hawaiian Islands, and revealed varied biogeographic affinities of the flora that are likely a product of both natural and anthropogenic dispersal.

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ABSTRACT

Background: A remarkable range of environmental conditions is present in the Hawaiian Islands due to their gradients of elevation, rainfall and island age. Despite being well known as a location for the study of evolutionary processes and island biogeography, little is known about the composition of the non-marine algal flora of the archipelago, its degree of endemism, or affinities with other floras. We conducted a biodiversity survey of the non-marine macroalgae of the six largest main Hawaiian Islands using molecular and microscopic assessment techniques. We aimed to evaluate whether endemism or cosmopolitanism better explain freshwater algal distribution patterns, and provide a baseline data set for monitoring future biodiversity changes in the Hawaiian Islands.

Results: 1,786 aquatic and terrestrial habitats and 1,407 distinct collections of non-marine macroalgae were collected from the islands of Kauai, Oahu, Molokai, Maui, Lanai and Hawaii from the years 2009-2014. Targeted habitats included streams, wet walls, high elevation bogs, taro fields, ditches and flumes, lakes/reservoirs, cave walls and terrestrial areas. Sites that lacked freshwater macroalgae were typically terrestrial or wet wall habitats that were sampled for diatoms and other microalgae. Approximately 50% of the identifications were of green algae, with lesser proportions of diatoms, red algae, cyanobacteria, xanthophytes and euglenoids. 898 DNA sequences were generated representing eight different markers, which enabled an assessment of the number of taxonomic entities for genera collected as part of the survey. Forty-four well-characterized taxa were assessed for global distribution patterns. This analysis revealed no clear biogeographic affinities of the flora, with 27.3% characterized as "cosmopolitan", 11.4% "endemic", and 61.3% as intermediate.

Conclusions: The Hawaiian freshwater algal biodiversity survey represents the first comprehensive effort to characterize the non-marine algae of a tropical region in the world using both morphological and molecular tools. Survey data were entered in the Hawaiian Freshwater Algal Database, which serves as a digital repository of photographs and micrographs, georeferenced localities and DNA sequence data. These analyses yielded an updated checklist of the non-marine macroalgae of the Hawaiian Islands, and revealed varied biogeographic affinities of the flora that are likely a product of both natural and anthropogenic dispersal.

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Graphical representation of dispersal-unit sizes by category of distribution. Graphical representation of dispersal-unit sizes of well-characterized Hawaiian non-marine algae, separated by category of distribution (as given for Figure 15).
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Figure 17: Graphical representation of dispersal-unit sizes by category of distribution. Graphical representation of dispersal-unit sizes of well-characterized Hawaiian non-marine algae, separated by category of distribution (as given for Figure 15).

Mentions: For each of the taxa in each of the categories above, thallus size and dispersal unit size ranges (as determined from the literature) were plotted to assess patterns associated with dispersal category. Thallus sizes were found to range from microscopic to macroscopic for representatives of all dispersal categories (although not necessarily for all individual taxa) (Figure 16). In contrast, dispersal unit size ranges were found to be uniformly ≤1 mm, and much smaller for both endemic and cosmopolitan taxa (Figure 17) (Additional file 2 contains a list of ordered taxonomic names for Figures 16 and 17).


The Hawaiian freshwater algae biodiversity survey (2009-2014): systematic and biogeographic trends with an emphasis on the macroalgae.

Sherwood AR, Carlile AL, Neumann JM, Kociolek JP, Johansen JR, Lowe RL, Conklin KY, Presting GG - BMC Ecol. (2014)

Graphical representation of dispersal-unit sizes by category of distribution. Graphical representation of dispersal-unit sizes of well-characterized Hawaiian non-marine algae, separated by category of distribution (as given for Figure 15).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4222836&req=5

Figure 17: Graphical representation of dispersal-unit sizes by category of distribution. Graphical representation of dispersal-unit sizes of well-characterized Hawaiian non-marine algae, separated by category of distribution (as given for Figure 15).
Mentions: For each of the taxa in each of the categories above, thallus size and dispersal unit size ranges (as determined from the literature) were plotted to assess patterns associated with dispersal category. Thallus sizes were found to range from microscopic to macroscopic for representatives of all dispersal categories (although not necessarily for all individual taxa) (Figure 16). In contrast, dispersal unit size ranges were found to be uniformly ≤1 mm, and much smaller for both endemic and cosmopolitan taxa (Figure 17) (Additional file 2 contains a list of ordered taxonomic names for Figures 16 and 17).

Bottom Line: The Hawaiian freshwater algal biodiversity survey represents the first comprehensive effort to characterize the non-marine algae of a tropical region in the world using both morphological and molecular tools.Survey data were entered in the Hawaiian Freshwater Algal Database, which serves as a digital repository of photographs and micrographs, georeferenced localities and DNA sequence data.These analyses yielded an updated checklist of the non-marine macroalgae of the Hawaiian Islands, and revealed varied biogeographic affinities of the flora that are likely a product of both natural and anthropogenic dispersal.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: A remarkable range of environmental conditions is present in the Hawaiian Islands due to their gradients of elevation, rainfall and island age. Despite being well known as a location for the study of evolutionary processes and island biogeography, little is known about the composition of the non-marine algal flora of the archipelago, its degree of endemism, or affinities with other floras. We conducted a biodiversity survey of the non-marine macroalgae of the six largest main Hawaiian Islands using molecular and microscopic assessment techniques. We aimed to evaluate whether endemism or cosmopolitanism better explain freshwater algal distribution patterns, and provide a baseline data set for monitoring future biodiversity changes in the Hawaiian Islands.

Results: 1,786 aquatic and terrestrial habitats and 1,407 distinct collections of non-marine macroalgae were collected from the islands of Kauai, Oahu, Molokai, Maui, Lanai and Hawaii from the years 2009-2014. Targeted habitats included streams, wet walls, high elevation bogs, taro fields, ditches and flumes, lakes/reservoirs, cave walls and terrestrial areas. Sites that lacked freshwater macroalgae were typically terrestrial or wet wall habitats that were sampled for diatoms and other microalgae. Approximately 50% of the identifications were of green algae, with lesser proportions of diatoms, red algae, cyanobacteria, xanthophytes and euglenoids. 898 DNA sequences were generated representing eight different markers, which enabled an assessment of the number of taxonomic entities for genera collected as part of the survey. Forty-four well-characterized taxa were assessed for global distribution patterns. This analysis revealed no clear biogeographic affinities of the flora, with 27.3% characterized as "cosmopolitan", 11.4% "endemic", and 61.3% as intermediate.

Conclusions: The Hawaiian freshwater algal biodiversity survey represents the first comprehensive effort to characterize the non-marine algae of a tropical region in the world using both morphological and molecular tools. Survey data were entered in the Hawaiian Freshwater Algal Database, which serves as a digital repository of photographs and micrographs, georeferenced localities and DNA sequence data. These analyses yielded an updated checklist of the non-marine macroalgae of the Hawaiian Islands, and revealed varied biogeographic affinities of the flora that are likely a product of both natural and anthropogenic dispersal.

Show MeSH
Related in: MedlinePlus