[Coral-List] Source for "coral occupy <1% of the seafloor but house more than 25% of species"

Thu Dec 17 00:12:12 UTC 2020

Hi Hanny,

I always thought the <1% came from the World Atlas of Coral Reefs (Spalding, M., Ravilious, C. & Green, E. University of California Press, 2001).

The UNEP-WCMC World Atlas of Coral Reefs map produced allowed an estimate of global shallow reef extent, concluding that “shallow coral reefs worldwide occupy some 284,300 sq km – “half the size of Madagascar, less than 1.2% of the world’s continental shelf area and only 0.089% of the total area of the worlds oceans”

Historic estimates of coral reef area have ranged from 255,000 (Spalding and Grenfell 1997) to 1,500,000 km2 (Copper, 1994) (Copper 1994) and from approximately 0.1–0.5% of the ocean floor. Some variability is to do with the method used: direct calculation from maps vs more predictive techniques based on reefal shelf area. And of course some of these differences are to do with how “coral reef” is defined. For example, Copper (1994) disagreed with the exclusion of “inter-reef tract”, suggesting that its inclusion might expand Smith and Crossland’s estimates to 1.5 million sq km (Copper 1994).

Recently, a team at Arizona State University used convolutional neural networks to generate a globally consistent coral reef probability map—a probabilistic estimate of the geospatial extent of reef ecosystems—combining a global mosaic of high spatial resolution Planet satellite imagery with regional Millennium Coral Reef Mapping Project reef extents to build training, validation, and application datasets. This new estimate gave a global extent range of 154,049 km2 to 301,110 km2, I think this is the most recent estimate of global shallow tropical coral reef extent! (Li, J. et al. A global coral reef probability map generated using convolutional neural networks. Coral Reefs, doi:10.1007/s00338-020-02005-6 (2020).)

Cheers!

Emma

Atmospheric CO2 this month: 412.89 ppm. It was 410.25 ppm last December (2019)
------------------------------------------------------------------------------------------------------------------------------
Dr. Emma Kennedy | Postdoctoral Research Fellow
Remote Sensing Research Centre | Room 416a | Level 4 | Chamberlain Building (#35)
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-----Original Message-----
From: Hanny Rivera <hrivera28 at gmail.com> 
Sent: Wednesday, 16 December 2020 4:46 AM
To: coral-list at coral.aoml.noaa.gov
Cc: David Obura <dobura at cordioea.net>
Subject: Re: [Coral-List] Source for "coral occupy <1% of the seafloor but house more than 25% of species"

Hi Dr. Obura,

I opted for a sentence very similar in spirit but with referenced numbers: "
While comprising only a small fraction of seafloor (0.2%) (Smith 1978), coral reefs are home to an estimated 830,000 species of organisms (Fisher et al. 2015)."

If you or anyone else is curious about the piece, you can find the full article here:
https://sciencepolicyreview.org/2020/08/coral-reefs-are-critical-for-our-food-supply-tourism-and-ocean-health-we-can-protect-them-from-climate-change/

I had actually meant to advertise it to this list a while ago and didn't get around to it. It's an overview of coral/reef focused policy and management efforts with some general policy recommendations.
Would love to hear any feedback from the community on it! Andrea Chan and Victoria Luu (both Knauss Policy fellows were co-authors).

Best,
Hanny

On Thu, Dec 10, 2020 at 10:25 PM Hanny Rivera <hrivera28 at gmail.com> wrote:

> Hi all!
>
> A while back, I had written asking for help tracking down the source 
> for this statement. Thank you to all who responded and helped! There 
> were a number of folks who also asked me to let them know what I 
> found. Sorry for the long delay! A recent twitter post reminded me I hadn't followed up.
>
> Anyways: The original reference (at least the most original that I 
> could
> find) is McAllister 1991. I had to do a lot of digging to find the 
> actual paper, though I finally came across it here:
> https://babel.hathitrust.org/cgi/ptid=uc1.31822009136755&view=1up&seq=
> 22 As you might see, it's not entirely clear where the numbers come 
> from though.
>
> Dan Barshis
> had pointed me to Smith 1978 
> (https://www.nature.com/articles/273225a0) as a more viable source for 
> the area estimation (though it's a bit outdated) and Fisher et al 2015 
> (
> https://www.sciencedirect.com/science/article/pii/S0960982214016236) 
> as a reference for species richness on reefs.
>
> A more recent area estimate is Spalding et al. 2001 (
> https://www.sciencedirect.com/science/article/pii/S0308597X17300635)
> which was pointed out to me by Dennis Allemand
>
> Dennis Allemand also has several other references for species #s that 
> live on reefs in his paper (
> https://www.sciencedirect.com/science/article/pii/S2352485518305978?vi
> a%3Dihub)
> on page 2.
>
> Thanks again all! Hope this is helpful for folks going forward.
>
> Best, Hanny
>
> --
> Hanny E. Rivera, Ph.D.
> Postdoctoral Associate and Lecturer
> Boston University, Biology Department
> Davies Marine Population Genomics Lab
> https://www.linkedin.com/in/hannyrivera
> http://sites.bu.edu/davieslab/members/
>

--
Hanny E. Rivera, Ph.D.
Postdoctoral Associate and Lecturer
Boston University, Biology Department
Davies Marine Population Genomics Lab
https://www.linkedin.com/in/hannyrivera
http://sites.bu.edu/davieslab/members/