the immortal red crust

  
  FHL Marine Botany  ::::::::::::::::::::::::::::::   Taxonomy | Habitat | Morphology | Life History | Ecology | Overgrowth
 

 

HABITAT

 

[H.1] Hildenbrandia sp. covering the walls of a tide pool at Botanical Beach. Note the other less abundant crusts (including a greenish crust right above Hildenbrandia). Also note the absence of trapped rocks, which would otherwise be scouring the bottom of the pool and preventing further colonization.

[H.2] Hildenbrandia rubra living with Littorina spp. on exposed rock in the high intertidal. This simple community/food web -- thin crust and periwinkle -- is a common site, and it is indicative of the simple life on the high shore.

  

Where in the world can you find Hildenbrandia?

In short, everywhere (1). H. rubra and H. occidentalis are readily found on both coasts of North America, from Alaska down to Panama, and from New Brunswick down to the Caribbean and other Atlantic islands. H. rubra (recently reported to be non-monophyletic; see Taxonomy) has also been found on both coasts of South America, all over European shores, on both coasts of Africa, on islands in the Indian Ocean, up and down the east coast of Asia, on Australian shores, and on many Pacific islands. This enormous range is most likely attributable either to vage taxonomic divisions or to Hildenbrandia's incredibly flexible ecology.

 

 

 

Where on the shore can you find Hildenbrandia?

In short, everywhere. Hildenbrandia grows on rocks of all shapes and sizes. The habitat in which it is most conspicuous is high intertidal pools (2). But Hildenbrandia can be found in nontrivial abundances in pools and exposed rock literally through the intertidal, and subtidally to at least -12 m for H. rubra and -21 m for H. occidentalis (3). In general, the more physically stressful the habitat, the more likely it is that Hildenbrandia will be growing there (e.g., high pools, sea caves, intertidal cobbles, and freshwater seeps). Hildenbrandia's tolerance of harsh environmental conditions is exemplified by the 5 freshwater congeners (see Taxonomy), whose ability to deal with physical stress has allowed them to escape the ocean.

 

 

 

 
   
  1. Range information retrieved from AlgaeBase. 2009. http://www.algaebase.org
  2. Dethier (1987, see below) reports that small, high tide pools are the one habitat where H. occidentalis is absent. Insofar as beach-going humans spend most of their time on the high shore (e.g., at high tide) and tend to stare into tide pools, we can assume that H. rubra is the more familiar species.
  3. Dethier, M. N. 1987. The distribution and reproductive phenology of intertidal fleshy crustose algae in Washington. Canadian Journal of Botany 65:9, pp. 1838 - 1850.