[Coral-List] FW: Loss of reef biodiversity - any recent data?

[David Blakeway]

Hi Peter, Zoe, Austin,

It does seem a bad situation. Losing diversity must be worse than losing
cover (not that they are independent).
But, especially in Zoe's Lizard Island example, it would be good to have
some sort of null model to compare the observed changes against. I mean a
theoretical population in which some proportion of species are
intermittently present and absent. If we time-sampled that population we
would record multiple local extinctions and new records, even if there were
no long term trend in diversity (that may be what your 'observed vs.
expected' tests are doing Zoe?). It is interesting from that perspective
that you found 51 new records in addition to the 28 + 31 losses. Though I
guess some of those new records may have been present all along.
I don't mean to imply that I doubt your conclusion that this could be a
real, anthropogenic, negative trend in diversity at Lizard Island. It seems
parsimonious, and the 2011-2017 loss is clear in Fig 1a & b. And I know you
will have already considered all these points. I am just trying to
understand what patterns *could* occur if (industrialized) humanity hadn't
appeared.

Austin, could you share some of the research questions you would like to
see addressed? I feel they would likely provide some perspective and focus
for us all.

Regards,
David