Sedum spathulifolium

A follow-up to the post on Eriophyllum lanatum, these are photographs on the same island by Sheila’s friend and co-kayaker, Stephanie Meinke. Thank you, Stephanie!

As Sheila noted to me, these plants were “growing in rocky crevices and depressions wherever a little bit of soil could accumulate”, a similar phenomenon to what was mentioned in this entry on lichen diversity. Over time, most biologically barren surfaces will eventually be colonized by some living pioneers. These pioneers are often (partially) replaced by a succeeding wave of other organisms, which are in turn succeeded by others and so on – a process termed succession. As mentioned by Brent in the comments of the Eriophyllum entry, the nearby Winchelsea Islands sustain a Garry oak woodland community of plants, while these seemingly do not, i.e., the Winchelsea Islands are at a later seral stage (a later stage in the successional process).

Knowing that the Winchelsea Islands are larger in area than the Ada Islands and assuming 1) both groups of islands have the same geological origins and substrate (a fairly safe assumption); 2) the surfaces of both groups of islands have been exposed from the ocean for a similar length of time (a not so safe assumption); and 3) the Winchelsea Islands peak higher than the Ada Islands (could someone please confirm?), what do you think are the factors that have prevented the Ada Islands from going through the successional stages that would allow them to similarly host a Garry oak woodland forest?

A quick note from Olduvai George: Happy Birthday, Charles Darwin.

Photography resource link: While browsing in a bookstore a couple days ago, I was delighted to discover “Tree – A New Vision of the American Forest”, by writer-photographer James Balog. When someone takes an entire day to photograph a tree section by section, you can imagine the result is going to be something spectacular. It is. Site navigation is a bit tricky, but check out the section on Trees – two of my favourites are “Stagg” Giant Sequoia and Sycamore. As an aside, there is no Amazon link because I’ve decided such a program isn’t the right thing for UBC BG in most cases (and I will be removing most of the few existing links to Amazon from the site).

Sedum spathulifolium
Sedum spathulifolium

7 responses to “Sedum spathulifolium”

  1. sheila williams

    Actually there was indeed a ‘pocket’ of garry oaks on Ada Island, certainly not a forest. Very stunted from wind and weather, in a spot sheltered from the North and facing South. Although definitely ‘bonsai’d’which added to their overall beauty, they were extremely healthy and vigourous.

  2. Daniel Mosquin

    Thanks for the correction, Sheila. It makes the question even more interesting, but doesn’t change the bones of it, i.e., “what is preventing the development of a woodland?”

  3. Karla Murray

    Thanks for featuring the sedum – it was what I focused on in the first picture. We have Sedum ternatum here in the Blue Ridge, and it is infrequent so I’ve not come across it in the wild yet – flowers are white.

  4. Maureen

    This doesn’t have anything to do with the beautiful photos in today’s BOTD post … just wanted to tell you thanks for what you said about the Amazon links … seems like thousands of blogs and other websites automatically link to when they write about books. I myself support my locally owned small bookstores rather than order through Amazon. Nothing against Amazon, but it is so huge it really doesn’t need more publicity. Why not link to some local Vancouver bookstores? Just a suggestion. I would understand if UBC chose not to do that either, in order not to play favorites.
    As usual, thanks Daniel for the great informative post. James Balag is someone I’ve admired for years. I wish I had the patience to make composite photos like he does. It takes an enormous amount of time at the computer. But it’s an amazing and effective way to convey the grandeur of large trees.

  5. Ron B

    Garry oak grows where it can get light. Precipitation tolerance wide, but cannot persist where other trees will overtake it (it is very slow growing, apparently even madrona is able to exclude it as at Three Tree Point, south of Seattle).
    Sedum spathulifolium is a superior ornamental species, probably the preeminent stonecrop (dwarf, creeping) type.

  6. Stephan Meinke

    We believe there are a few reasons why the Gary Oak have not developed a grove on this island:
    1) The island is smaller than Winchelsea, as mentioned previously, this affects fresh water retention.
    2) Most of the island has a southern aspect making it very dry in the summer. We have noticed recently dead oaks on other nearby islands as a result of last two years of dry summers.
    3) Most of the island will be subject to salt spray during storms.
    4) The island is lower than Winchelsea but more significantly it generally slopes down gently on the side of the prevailing winds whereas Winchelsea rises more steeply from the water. I believe this increases the amount of wind that the plants are subjected to on this Ada island. In addition there are few places on the island where soil and fresh water can collect.
    I would agree that all the islands share a similar geologic origin, but I would be careful in suggesting that they share similar substrates. The location the picture was taken from has granitic bedrock, but many of the islands also have basaltic bedrock. My wife and I will have to further investigate the differences between the islands on our next trip.

  7. Daniel Mosquin

    Very comprehensive, Stephan!
    Those are all likely to be contributing factors. My line of thinking had to do with the general lack (and inability) of soil establishment due to the physical properties of the island, which as you rightly point out enables fresh water retention. I also speculated that there might be issues of mechanical abrasion from wind and wave action (and from sea lions moving about, perhaps!).
    While what we (you and I, so far) think isn’t enough to say something is true in the scientific sense of the word, the keen observations and informed imagination of natural history can help lead science in the right direction of developing hypotheses to be tested. After some experimentation, what we think can either be verified, discarded as untrue or cited as “not yet proven or unproven”.

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