[Coral-List] Dendrogyra

[sealab at earthlink.net]

Dear Gene,

You seem to be downplaying the significance of losing rare species.

Maybe I’m too sensitive because pillar coral are a particular favorite of mine, but I thought you might find this paper to be of interest.

I’ve highlighted some key points below.

Regards,

Steve Mussman

Frontiers | Fallen Pillars: The Past, Present, and Future Population Dynamics of a Rare, Specialist Coral–Algal Symbiosis | Marine Science

https://www.frontiersin.org/articles/10.3389/fmars.2019.00218/full

Demographic modeling based on molecular data agreed with the geological record that D. cylindrus was historically not a dominant species on Caribbean reefs and yet was able to survive as the sole remaining species in the genus. The forecasted increasing frequency of extreme warm water events in combination with associated disease outbreaks, and the observed absence of sexual recruitment in this species, project a high likelihood that D. cylindrus will become locally extinct in the Florida Keys in modern times (see below). The consequences of the loss of rare coral species and their symbionts are unknown but evidence from other ecosystems indicates that losing rare species can destabilize communities and degrade ecosystem function (Theodose et al., 1996; Lyons and Schwartz, 2001; Mouillot et al., 2014).

What are the consequences of losing rare species? Experimental removal of rare species was shown to reduce ecosystem resistance to invasion by an exotic grass (Lyons and Schwartz, 2001). It is possible that less common species significantly contribute to the proper maintenance of ecosystem function. Rare plant species were shown to more significantly impact nutrient cycling and retention in an alpine meadow compared to more abundant species (Theodose et al., 1996). In a comprehensive study of species occurrence datasets from coral reefs, alpine meadows, and tropical forests, rare species were repeatedly shown to predominantly support vulnerable functions (Mouillot et al., 2013). These vulnerable functions were defined as ecosystem roles with low redundancy, in that uncommon species with distinct trait combinations bolstered these particular functions. Despite the high diversity in these ecosystems, abundant species did not insure against the services lost by removing rare species (Mouillot et al., 2014). Therefore, maintaining these uncommon species is essential to overall community functional diversity.

Losing rare species and their corresponding functions may further reduce reef resilience and thus exacerbate coral reef decline beyond what has been predicted (Hoegh-Guldberg et al., 2017; Hughes et al., 2017).

Whether we and our politicians know it or not, Nature is party to all our deals and decisions, and she has more votes, a longer memory, and a sterner sense of justice than we do. (Wendell Berry)

On 5/25/21, 2:54 PM, Eugene Shinn via Coral-List <coral-list at coral.aoml.noaa.gov> wrote:

In all my 60+ yearsdiving in the Florida Keys (starting in my senior

year in high school(1953) I never saw a mailbox placed on pillar coral.

Remember there were few residents in the Keys and major canal dredging

started in the late 1950s extending into the early 1960s. I watched it

all. Major changes began in the 1970s much of it spurred on later by

creation of the Key Largo Coral Reef Sanctuary, the first Burger King,

and creation of dive shops.

While doing geological research and drilling around 100 reef cores we

never encountered Pillar coral. Living ones were rare in the 50s and 60s

and were never considered significant reef builders. They never could

have created significant habitat for reef fishes or other reef fauna. I

have photographed large ones on Jamaican reefs but I can not speak for

the rest of the Caribbean.Nevertheless, I seriously doubt they have ever

been significant reef builders anywhere in the Caribbean. They also do

not appear in exposures of Pleistocene coral reefs. You will not see

them in the beautiful exposures of reef limestone in the Florida Keys

Fossil reef quarry on Windley key.Gene

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