In Alaska’s Kenai Fjords National Park, glaciers can be found at or near sea level. As they retreat (and all glaciers below 1500m (4905 ft.) in Alaska are retreating), sheer walls of bedrock cliffs are sometimes exposed. Once this new habitat becomes available, organisms quickly begin to colonize.
Lichens and mosses are generally the first macro-organisms to establish on the rock–a ecological process called primary succession. In this step of succession, organisms establish in an area where the initial ecological factors that determine abundance and distribution are solely abiotic (non-living): factors like slope, mineral composition, light availability, wind exposure, and so on. Once living things are present (and humus from the breakdown of these living things), it becomes more complicated for any new arrivals. In secondary succession, these new colonizers have to additionally contend with biotic factors like competition for sparse nutrients, herbivory, or space for seedling germination.
Despite the two photos today both being of post-glacial seaside cliffs (and quite near each other, at that), it is apparent that two different community assemblages have emerged through differences in the ecological factors affecting succession. I suspect that one of the differences between the two community assemblages is the angle of the cliffside slope (but one would need to do the research!). In the left image with the gulls, one could make the argument that a slightly gentler slope has permitted more organic material to accumulate in the crevices and benches. This has eventually led to the establishment of a Carex macrochaeta-dominated community (I’m best-guessing the identity from this technical report: Landcover Classes, Ecological Systems and Plant Associations: Kenai Fjords National Park (PDF)), which in turns provide favoured habitat for nesting gulls. The streaking on the still-exposed rocks is possibly from nitrogen-deposition via the gulls; few mosses seem to survive this (spottily, it seems, where there are overhangs) and there is certainly a different lichen community compared to the second photo. Sharp eyes will notice the first shrubs or young trees establishing in areas where the long-awned sedge is particularly abundant, presumably where organic material accumulation is the highest.
In the second image with the puffins, the near-vertical slope prevents organic accumulation in all but the narrow crevices. While there are a few individual Carex plants present, forbs such as Primula pauciflora and Potentilla sp. are evident. These perhaps arrived via bird dispersal or wind from nearby tundra. The crustose lichen community on the rock face is–dare I say it–evidently “old-growth”, with lichens layering upon lichens such that no bare rock is exposed. Despite having less overall vegetative biomass, I believe the second image shows a longer-established community; this photo was taken further away from the terminus of the glacier(s).
Feel free to disagree with my speculation!