Climate Change Will Lead to the Extinction of Coral Reef Fish

One of the many factors causing the global loss of reef building corals is anthropogenic climate change, which is slowly warming the world’s oceans. When summertime temperatures are warmer than usual, corals can die from “bleaching” and disease outbreaks. This in turn is devastating for the countless organisms that inhabit coral reefs.

A new paper (Graham et al 2011) by an international team of marine scientists describes a framework to predict and measure the impacts of coral loss on fish populations. They created an “extinction risk index” for reef fish, based on the habitat requirements, feeding ecology and other traits of each species. For example, obligate corallivores, fish that feed on corals such as butterflyfish, were scored as highly sensitive. In all, 56 of the 134 coral fish species studied were found to be at risk from loss of their habitat, shelter and food sources caused by climate change. Those most in jeopardy were the smaller fishes with specialized eating and sheltering habits. One of the interesting findings from this exercise is that fish predicted to be vulnerable to climate change are not vulnerable to over-harvesting, and vice versa.

The team then tested their model by comparing its predictions to documented fish extinctions caused by a massive coral bleaching event that occurred in 1998 in the Indian ocean in which whole landscapes of corals died off. The fish species predicted to be the most sensitive to such habitat degradation experienced the greatest population losses.

Taken broadly, their results indicate that more than a third of coral reef fish species are in jeopardy of local extinction from the impacts of climate change.

“The loss of particular species can have a critical effect on the stability of an entire ecosystem – and our ability to look after coral reefs depends on being able to predict which species or groups of fish are most at risk,” explains lead author Dr. Nick Graham of the ARC Centre of Excellence in Coral Reef Studies and James Cook University. “Until now, the ability to do this has been fairly weak.”

“Where there is a widespread death of corals from a climate-driven event such as bleaching, the fish most affected are the ones that feed or shelter almost exclusively on coral.”

The study does, however, offer encouragement by showing that the fish most at risk from climate change are seldom those most at risk from overfishing or other direct human impacts, pointing to scope to manage reef systems and fishing effort in ways that will protect a desirable mix of fish species that promote ecosystem stability.

Dr. Tim McClanahan of the Wildlife Conservation Society explains:

Critically, the species of fish that are important in controlling seaweeds and outbreaks of deleterious invertebrate species are more vulnerable to fishing than they are to climate change disturbances on coral reefs. This is encouraging, since local and regional commitment to fisheries management action can promote coral recovery between disturbances such as storms and coral bleaching events.

One thing I really like about the paper is that it focuses on the impacts of habitat loss on reef inhabitants. Corals are dying in droves from climate change and local impacts like runoff from coastal deforestation, but reef scientists are not worried about coral extinctions. It is reef ecosystems that we are going to lose along with all the ecological splendor and economic value that is based on them.

Their paper, “Extinction vulnerability of coral reef fishes,” by Nicholas A. J. Graham, Pascale Chabanet, Richard D. Evans, Simon Jennings , Yves Letourneur, M. Aaron MacNeil, Tim R. McClanahan, Marcus C. Öhman, Nicholas V. C. Polunin and Shaun K. Wilson, appears in the latest issue of the journal Ecology Letters.

New study finds growth of corals on the Belize Barrier Reef is slowing

A new study just published in PLos One (Castillo et al 2010) indicates massive corals (Siderastrea sideria) on the outer reefs of the Belizean Barrier Reef are growing more slowly than they did during the early and middle 20th century.

Lead author Karl Castillo (a post doc in my lab) is from southern Belize near the reefs where the study was conducted.  He and my UNC colleague Dr. Justin Ries took core samples from 13 massive starlet corals, a species that can grow to sizes of more than 1 meter across. They then measured the thickness of growth bands in the coral samples.


Core sections represent the most recent years of skeletal extension for Siderastrea siderea from the (A) forereef [core FR-12], (B) backreef [core BR-06], and (C) nearshore reef [core NS-14]. Numbers correspond to year of paired high-low density annual growth bands. Asterisks correspond to the annual growth bands formed during the 1998 coral bleaching event.


Natural and anthropogenic stressors are predicted to have increasingly negative impacts on coral reefs. Understanding how these environmental stressors have impacted coral skeletal growth should improve our ability to predict how they may affect coral reefs in the future. We investigated century-scale variations in skeletal extension for the slow-growing massive scleractinian coral Siderastrea siderea inhabiting the forereef, backreef, and nearshore reefs of the Mesoamerican Barrier Reef System (MBRS) in the western Caribbean Sea.

Methodology/Principal Findings

Thirteen S. siderea cores were extracted, slabbed, and X-rayed. Annual skeletal extension was estimated from adjacent low- and high-density growth bands. Since the early 1900s, forereef S. siderea colonies have shifted from exhibiting the fastest to the slowest average annual skeletal extension, while values for backreef and nearshore colonies have remained relatively constant. The rates of change in annual skeletal extension were −0.020±0.005, 0.011±0.006, and −0.008±0.006 mm yr−1 per year [mean±SE] for forereef, backreef, and nearshore colonies respectively. These values for forereef and nearshoreS. siderea were significantly lower by 0.031±0.008 and by 0.019±0.009 mm yr−1 per year, respectively, than for backreef colonies. However, only forereef S. siderea exhibited a statistically significant decline in annual skeletal extension over the last century.


Our results suggest that forereef S. siderea colonies are more susceptible to environmental stress than backreef and nearshore counterparts, which may have historically been exposed to higher natural baseline stressors. Alternatively, sediment plumes, nutrients, and pollution originating from watersheds of Guatemala and Honduras may disproportionately impact the forereef environment of the MBRS. We are presently reconstructing the history of environmental stressors that have impacted the MBRS to constrain the cause(s) of the observed reductions in coral skeletal growth. This should improve our ability to predict and potentially mitigate the effects of future environmental stressors on coral reef ecosystems.

They found that over the last 90 years, growth rates for corals in the forereef zone shifted from being the fastest of the three zones to the slowest, while the skeletal extension rates of corals closer to the coast remained relatively stable.

“Massive starlet corals are like old-growth trees in a forest, and the annual extension bands in these core samples tell a cautionary tale,” said the study’s lead author, Karl Castillo, Ph.D., a postdoctoral research associate in the marine sciences department in the UNC College of Arts and Sciences. “The forereef corals used to have the greatest linear extension, but since early last century their growth has clearly been stunted.”

“This suggests that backreef and nearshore corals may be accustomed to stressful conditions because of their regular exposure to high environmental stress,” he said. “But forereef corals — which have probably been less conditioned by baseline natural stressors — appear to be more susceptible to recent human-made impacts such as ocean warming.”

Listen to an interview with Glen De’ath about similar findings on Australia’s Great Barrier Reef here.

Republicans announce new climate strategy: Abandon Earth

Unfortunately, no, this isn’t a piece from the Onion: GOP members want to scrap NASA’s climate research funding to instead invest in a new mission to outer space. Have they been talking to Stephen Hawking?

Reposted in full from the Wonk Room:

Republicans have a new idea: instead of wasting time protecting this planet, let’s figure out how to escape it.

Over a hundred years ago, scientists started warning that the unconstrained burning of fossil fuels could make planet Earth uninhabitable for human civilization. Since then, we have spewed billions of tons of greenhouse pollution into the atmosphere, acidifying the oceans, devastating ecosystems, and intensifying catastrophic weather. Fortunately, scientists have also found that the strategy of reducing pollution would unleash an economic revolution with clean energy and keep our planet friendly to the human race. Many of these scientists work for the National Aeronautics and Space Administration’s (NASA), which has a billion-dollar budget for studying the “natural and man-made changes in our environment” that “affect the habitability of our planet.”

However, Republicans in Congress find the clean energy pathway unreasonable, arguing the costs of reducing our toxic dependence on coal and oil would be too great. Perhaps stung by accusations that they are simply the Party of No, a group of House Republicans have now put forward an alternate strategy to avoiding disastrous global warming: the first step being to scrap NASA’s world-leading climate science research funding, and direct it instead into sending people into unpolluted outer space:

Global warming funding presents an opportunity to reduce spending without unduly impacting NASA’s core human spaceflight mission. With your help, we can reorient NASA’s mission back toward human spaceflight by reducing funding for climate change research and reallocating those funds to NASA’s human spaceflight accounts, all while moving overall discretionary spending toward 2008 levels.

The signatories of this Abandon Earth letter to House Appropriations Committee Chairman Harold Rogers (R-KY) and Commerce, Justice, and Science Subcommittee Chairman Frank Wolf (R-VA) are Reps. Sandy Adams (R-FL), Rob Bishop (R-UT), Mo Brooks (R-AL), Jason Chaffetz (R-UT), Pete Olson (R-TX) and Bill Posey (R-FL), all from districts that play a role in the National Aeronautics and Space Administration’s (NASA) manned spaceflight program. As they are currently on planet Earth, they are also all from districts threatened by the effects of global warming.

Although the signatories don’t explicitly state that the goal of shifting funding from climate research into manned spaceflight is to find a new home for the 350 million people of the United States, one can only assume that they support that goal. Signatory Mo Brooks (R-AL), the new subcommittee chair for the House science committee’s panel on basic research and education, told ScienceInsider that “I haven’t seen anything that convinces me” that greenhouse emissions should be reduced, and will hold hearings about cutting as much of the U.S. climate research budget as possible.

As they are responsible politicians who worry about “[f]uture generations of Americans,” they surely don’t intend to stick our children with catastrophic sea level rise, summer-long heat waves of over 100 degrees, superfueled storms and floods, intense droughts, desertification, and mass species extinction without offering them a Planet B:

Space is the ultimate high ground and nations such as China, Russia, and India are anxious to seize the mantle of space supremacy should we decide to cede it. We must not put ourselves in the position of watching Chinese astronauts planting their flag on the moon while we sit earthbound by our own shortsightedness. Future generations of Americans deserve better.

The Planet-B Republicans rightfully recognize that the moon — without an atmosphere or liquid water — would lead to serious resource competition between the 6 billion people now on this planet, perhaps with China the greatest threat to our post-Earth plans. Although China does have a growing space program, its government is primarily investing in the “save this planet first” strategy, spending twice as much as the United States on clean technology, establishing mandatory standards for renewable energy production, mandatory energy efficiency standards, and mandatory fuel economy standards.

Some people might say that ramping up interplanetary travel from the 12 men who walked on the moon to millions or billions of people, while figuring out how to terraform lifeless planets when we’re failing to keep our own climate stable, in a few decades is a higher risk, more costly endeavor than increasing energy efficiency and renewable energy by one or two percentage points a year. Although those people would be technically correct, they would also be failing to appreciate the total awesomeness of the Abandon Earth plan.

Coral Reef Baselines

The pristine or natural state of a population or community is called the baseline in conservation biology. A baseline serves as a guide for setting conservation and restoration targets. Unfortunately, scientists rarely have reliable information on baselines, because in most cases quantitative data are not collected until long after the resource has been modified. This is particularly true for marine communities which can be difficult and expensive to monitor.

A new paper in Coral Reefs “Assessing loss of coral cover on Australia’s Great Barrier Reef over two decades, with implications for longer-term trends” (Sweatman et al. 2011) tries to get at what the baseline is for the Great Barrier Reef (GBR) using the results of ecological surveys performed by the Australian Institute of Marine Science (AIMS). Sweatman et al argue that the AIMS surveys, which began in 1986, are the most reliable evidence we have and that other evidence should be ignored. However, many other scientists surveyed reefs on the GBR (for various reasons) decades before AIMS began it’s monitoring program. Three papers have collated that data and combined it with the AIMS survey data to estimate how the GBR has changed over the last 4-5 decades.

The first such paper (published in Nature by Bellwood et al 2004) included this graphic of long-term change in coral cover (the percentage of the sea floor covered by living corals – because corals facilitate so many reef inhabitants, living coral cover is a key measure of reef habitat quality and quantity, analogous to the coverage of trees as a measure of tropical forest loss):

Figure 1 (from Bellwood et al 2004). Degradation of coral reefs. a, Results of a meta-analysis of the literature, showing a decline in coral cover on the Great Barrier Reef. Each point represents the mean cover of up to 241 reefs sampled in each year. b, The recorded number of reefs on the Great Barrier Reef, Australia, substantially damaged over the past 40 yr by outbreaks of crown-of-thorns starfish (COTS) and episodes of coral bleaching.

The second study (Bruno and Selig 2007) is a meta-analyses of coral reef survey data from 2667 reefs across the Indo-Pacific performed between 1968 and 2004 (Fig. 2).

Figure 2 (from Bruno and Selig 2007). Coral cover in ten Indo-Pacific subregions in each of three periods. Plotted values are means +/- 1 SE and values above each bar are the subregional sample sizes. *=no data available

The third paper, Pandolfi et al 2003, used a variety of historical and palontological data sources in an attempt to reconstruct the longer-term, including pre-human, history of the GBR and other reefs around the world (Fig. 3).

Figure 3 (from Pandolfi 2003). Time trajectories for reef regions over seven cultural periods.

All three studies essentially concluded that GBR coral cover and overall ecosystem health began to decline decades ago, despite the fact that the GBR is currently in better shape than many of the world’s reefs.

Sweatman et al dismiss pre-1986 data from all three studies, arguing that only AIMS survey data are suitable, and thus conclude that the GBR has changed little if at all due to human influences: “We argue that the GBR is currently less degraded from its natural, resilient state than some published reports have asserted”. Global climate change skeptics have frequently use a very similar approach: they rationalize cherry picking a favored data set and time interval in an attempt to show land and ocean temperatures haven’t increased, that sea ice hasn’t declined, etc.

Abstract (from Sweatman et al 2011):

While coral reefs in many parts of the world are in decline as a direct consequence of human pressures, Australia’s Great Barrier Reef (GBR) is unusual in that direct human pressures are low and the entire system of 2,900 reefs has been managed as a marine park since the 1980s. In spite of these advantages, standard annual surveys of a large number of reefs showed that from 1986 to 2004, average live coral cover across the GBR declined from 28 to 22%. This overall decline was mainly due to large losses in six (21%) of 29 subregions. Declines in live coral cover on reefs in two inshore subregions coincided with thermal bleaching in 1998, while declines in four mid-self subregions were due to outbreaks of predatory starfish. Otherwise, living coral cover increased in one subregion (3%) and 22 subregions (76%) showed no substantial change. Reefs in the great majority of subregions showed cycles of decline and recovery over the survey period, but with little synchrony among subregions. Two previous studies examined long-term changes in live coral cover on GBR reefs using meta-analyses including historical data from before the mid-1980s. Both found greater rates of loss of coral and recorded a marked decrease in living coral cover on the GBR in 1986, coinciding exactly with thestart of large-scale monitoring. We argue that much of the apparent long-term decrease results from combining data from selective, sparse, small-scale studies before 1986 with data from both small-scale studies and large-scale monitoring surveys after that date. The GBR has clearly been changed by human activities and live coral cover has declined overall, but losses of coral in the past 40–50 years have probably been overestimated.

For several reasons listed below, I think the main conclusion of Sweatman et al is unsupported once you consider the scientific record as a whole.

1) There is much more pre-1986 data available than Sweatman et al suggest

Our study alone (Bruno and Selig) includes data from 154 surveys of reefs across the Indo Pacific performed between just 1980 and 1982. We found that mean coral cover was 42.5% (95% CI, 39.3 and 45.6). Our analysis includes 104 GBR surveys performed between 1968 and 1983, all from published literature (see Fig. 2).

2) Baseline data from other regions indicates that historically GBR coral cover was higher than it is today (or was in 1986)

In the Caribbean a small number (a few dozen) of reliable quantitative surveys from before the early 1980s suggest the regional mean for coral cover was 30-40% (Gardner et al 2003, Schutte et al 2010: see Figs. 5 and 6 below). Because countless well trained reef scientists were working throughout the region and observed the state of reefs over the last 100 years, most Caribbean reef scientists think that historically, the regional mean of Caribbean coral cover was higher than this; probably closer to 50% (or greater). Most Caribbean reefs of this era were dominated by Acropora spp., as can be seen in the photo below from 1974:

Sweatman et al are effectively arguing that the GBR has naturally lower coral cover (averaging a mere 28%) than the Caribbean, which lacks plating species; even in dense thickets of branching Acroporids (as seen above), Caribbean coral cover rarely exceeds 70% whereas on the GBR, cover can easily reach 100% (see the photo below).

We also have substantially more older survey data for several non-GBR Pacific regions than are available for the GBR. For example, Gomez et al surveyed more than 600 sites in the Philippines in 1981 (Gomez et al 1981). Their work clearly shows a coral baseline far higher than today in the Philippines, the GBR or anywhere else in the world. Also see Fig. 4 below from Bruno and Selig (2010) that suggests the values reported in Gomez et al are representative of other regions at the time. And note the striking difference in the distribution of coral cover values among reefs between the early 1980s and for more recent surveys. Does it look like the Indo-Pacific as a whole, the Philippines or the reefs off mainland Asia haven’t changed? NO! They clearly have. Even assuming we had no pre-1986 coral cover data for the GBR, I don’t think it is logical to assume that the GBR hasn’t followed these global trends and that it has a much lower coral cover baseline than the rest of the world.

Figure 4. (From Bruno and Selig 2007) Histograms illustrating percent coral cover in the Indo-Pacific and selected subregions during different periods.

3) The GBR was already disturbed and changing by the time the AIMS monitoring program began

AIMS began surveying a few dozen reefs along the GBR in 1986 after it became obvious that the reef ecosystem was changing due to over-fishing, sediment pollution from coastal development, ocean warming and predator outbreaks. Sweatman et al argue the values recorded by the early AIMS LTMP surveys of the late-1980s, when cover was roughly 30%, are representative of the pre-human, historical baseline.  I see no reason to assume this given the well-documented anthropogenic disturbances that were already affecting the reef by then (see Fig 1).

4) Nearshore reefs were smothered by sediment from coastal development a century ago

Sweatman et al: Observations and models of the dynamics of flood plumes (Devlin et al. 2001) show that it is the inshore reefs that are frequently exposed to runoff, but these reefs constitute less than 5% of the reef area of the GBR.

Sweatman et al cite the early work of Devlin et al (2001), suggesting that only the inshore reefs are ‘frequently’ exposed to runoff, but this isn’t the case. More recent evidence from CSIRO suggests that terrestrial runoff affects a much greater area of the GBR than Sweatman et al suggest:

The remotely sensed images, taken from February 9 to 13 this year, challenge conventional thought that sediment travelling from our river systems into the GBR is captured by the longshore current and travels no more than 10 to 15km offshore, affecting only the inner Great Barrier Reef Lagoon and the inner reef corals.

Images captured by CSIRO show large plumes of terrestrial material following unconventional patterns and travelling quite fast as far as 65 to 130km, to the outer reef and, in some instances, travelling along the outer reef and re-entering the reef.

Sediment, brown and green against the blues that show 'normal' reef waters, from the Annie River (1), North Kennedy River (2), Normanby River (3) and Marrett River (4) washes into Princess Charlotte Bay, past Flinders Island (5) and along Corbett Reef (6) before being carried into the Fairway Channel (7) and into the ocean. (Credit: CSIRO: GeoScience Australia)

To quote CSIRO scientist Arnold Dekker: “A re-think is needed now that we know where flood plumes go, and what this means as organic micropollutants may be travelling to parts of the reef scientists hadn’t thought to look before”. This suggests that both mid and outer shelf reefs are impacted periodically by flood disturbance – traveling as far as 65-135km, and affecting much more than the 5% that Sweatman et al claim. Why is this important? Scientists from AIMS have already implicated nutrient runoff and and crown of thorns starfish plagues, suggesting that “frequent A. planci outbreaks on the GBR may indeed be a result of increased nutrient delivery from the land”. Further research by Jupiter et al from from the southern GBR shows that whilst the inshore reefs that are exposed to chronic high-magnitude events are clearly degraded, near shore reefs influenced by episodic, high-magnitude exposure are also showing signs of stress, with persistent high cover of fleshy macroalgae. While Sweatman et al select (cherrypick?) the stories that makes the GBR look resilient:

“There is other evidence of recovery; 6 years after bleaching, survey sites on inshore reefs in the Innisfail sector had the highest densities of juvenile corals (<10 cm diameter) of any inshore reefs of the GBR (Sweatman et al. 2007), though the densities of juvenile corals were much lower on inshore reefs in the Townsville sector.”

The inclusion of such data largely glosses over some of the other studies Sweatman et al have co-authored, showing reduced resilience and phase shifts from coral to macroalgal dominance: “In this study, 11 years of field surveys recorded the development of the most persistent coral–macroalgal phase shift (>7 years) yet observed on Australia’s Great Barrier Reef (GBR)” (read more)

5) The early GBR survey data are sound

Sweatman et al: Another concern is that the objectives of many early reef studies predisposed them to select areas of high coral cover…This change in research emphasis is likely to be reflected in the choice of study sites, with early studies selecting sites for their diverse communities and high coral cover where the study organisms are abundant and large samples can be found in a small area.

I initially thought this too, but once I got into the literature, I was reminded that the late 60s and early 70s were the heyday of disturbance ecology and most reef ecologists were community ecologists, and like their peers working in other systems, focused almost entirely on the effects of large disturbances on reef communities, e.g., Endean and Stablum 1973, Endean 1977, Connell 1978, Done 1992, Done et al. 1991, etc.  Thus, if anything, I think most the early bias is in the other direction.  Regardless, I agree site selection biases, both then and now, complicate long-term trend interpretation.

Sweatman et al: While the AIMS long-term data show a decline in average coral cover on GBR reefs from 28.1 to 21.7% between 1986 and 2004, two studies (Bellwood et al. 2004; Bruno and Selig 2007) based on unweighted meta-analyses have suggested that average coral cover on GBR reefs was considerably higher in the 1960s and 1970s than in the 1980s. Bellwood et al. (2004) presented a plot of mean coral cover on the GBR indicating that cover halved from ~40% in the early 1960s to ~20% in 2000, almost three times the rate of decline in the AIMS long-term monitoring data.

Bruno and Selig (2007) used information from 2,667 sites to assess change across the Indo-Pacific, including the GBR as one subregion. Based on published studies including AIMS monitoring data, they found that mean coral cover on the GBR declined by ~25% (in relative terms) from the period 1968–1983 to 1984–1996 and then was relatively stable until the end of their study period in 2004. We argue that this difference is substantially due to a change in the scale of surveys and in survey methods. The most compelling evidence for this is that, in the data sets of both studies, the annual estimates of the mean for coral cover on the GBR drop abruptly in 1986, the first year of large-scale moni- toring on the GBR, and then vary rather little around the new level in subsequent years.

The apparent abrupt drop in average coral cover on the GBR in 1986 is most probably due to the inclusion of AIMS monitoring data with cover estimates from small selected patches of reef from small-scale studies…

Like Sweatmean et al, Bruno and Selig and Bellwood et al found that at a regional scale, average coral cover on the GBR has changed little since 1984 (see Figs. 1 and 2 above).  A similar pattern has been documented for the Caribbean, where substantial coral loss in the early 1980s changed to relative regional stasis since (Figs. 5A and C), i.e., a very similar pattern has been found in other regions (regardless of the scale of surveys and survey methods – also see Bruno and Selig for other Indo-Pacific examples) in which AIMS has never surveyed. 

Figure 5 (From Schutte et al 2010). Annual cover values (±1 SE, closed circles, left y-axis) and site sample sizes (open circles, right y-axis) for (A) mean coral cover for all sites in the Caribbean basin (n = 1962; star: 1980, the year in which Hurricane Allen struck and white band disease outbreaks began); (B) mean macroalgal cover for all sites for which data were available (n = 875; star: 1983, the year in which the Diadema antillarum die-off began); (C) mean coral cover for all sites in the greater Caribbean except those in the Florida Keys (FLK; n = 1515); and (D) mean coral cover for all sites in the FLK subregion (n = 447)

6) Are the AIMS LTMP data sound?

Here’s what Professor Mike Risk had to say about the AIMS monitoring program:

“One of the largest monitoring programmes is operated by the Australian Institute of Marine Sciences (AIMS) (e.g. Sweatman et al. 1998). Like all large monitoring programmes, it is expensive and time-consuming. It is designed to detect changes over time in reef communities at a regional scale. There has been a massive amount of data collected in this programme, which is commendable. On the other hand, as annual surveys are run between September and May, beginning in the north and working south, seasonal changes will be difficult to separate from spatial and temporal changes. It will take perhaps 30-50 years to accumulate enough baseline data to allow useful generalizations to be made” – (Risk 1999)

The AIMS survey data presented in Sweatman et al used the “manta tow” technique; snorkelers are towed behind a boat, over a reef and visually estimate coral cover within 10m wide swaths to categories such as 0-5%, >5-10%, 10-20%, 20-30%, etc. I think the manta technique can be a valid tool for estimating crude spatio-temporal trends in coral cover. I even used the AIMS manta data in our Bruno and Selig paper, although I haven’t used it since (having spoken with several former AIMS technicians about the technique and it’s accuracy and precision). In short, Sweatman et al argue that their manta tow data is so superior to data from other sources, that only the AIMS manta data should be used to asses long-term trends in GBR state. I disagree; not to knock the AIMS manta data, but it is a visual quasi-quantitative estimate collected by technicians as compared to the pre-1986 GBR data which was all collected by renouned PhD scientists, e.g., Endean and Stablum, Connell, Done, etc, that spent their lives studying the GBR.

Furthermore, these pre-1986 GBR surveys were performed using wholly quantitative techniques such as underwater photography to estimate coral cover. I just don’t buy the argument that the AIMS-intern-manta tow data are superior to quantitative surveys by trained PhD scientists. For one, how can we know that the visual estimation of “20%” coral cover has stayed constant over time? Secondly, I really doubt any technique only capable of estimating coral cover to the nearest 10% (i.e., with such low precision) is sensitive enough to even detect the gradual decline in coral cover that has been reported for the GBR and elsewhere, e.g., ~0.5-2% a year. (Just take a look at the error bars in Fig. 2 from Sweatman et al in the Abstract above). Third, I doubt the AIMS manta surveys were run long enough to detect regional trends without including data from other sources. Given the inherent noise in the system, I usually look for 30+ years of data before I try to test for a large-scale trend.

Fourth, I think it is somewhat misleading to represent the manta tows as having far greater spatial coverage. This is only true if you compare the cumulative area of the samples. However, unlike the manta tows, quantitative benthic reef surveys include extensive independent replication and if properly designed will produce coverage estimates that are representative of the broader surrounding benthos.

Finally, I suspect that the manta technique substantially underestimates coral cover because it does not (and cannot) correct for uninhabitable (by corals) substrate that is encountered in surveying. When coral scientists use the term “coral cover”, they mean the percentage of the sea floor occupied by stony corals that is habitable by this group, i.e., hard substrate, not sand or other types of soft substrate. This is easy to factor out with other quantitative survey methods; you just divide the total coral cover by the total hard (suitable) substrate cover to calculate “coral cover”.   In most cases, the hard/suitable cover is nearly 100%. But because manta tows cover wide and long swaths of reef, they inevitably include small and large patches of sand, etc, and it is impossible to do the mental math to factor this out when estimating the coverage of corals and other benthic taxa while getting pulled behind a boat in shark infested waters!  (manta towing is a job for the young and immortal!) If you compare the AIMS manta data to the quantitative AIMS video transect data (~48 reefs surveyed annually) you can see this artifact: from 1994-2003 the mean coral cover from the AIMS manta tows was 21.7 +/- 0.5 (1 se) and 30.7 +/- 0.9 from the video transects. This suggests that the drop in GBR coral cover in the mid-1980s could be due to a methodological bias of the manta tow technique. Would this mean that the GBR hasn’t lost any coral or that “losses of coral in the past 40–50 years have probably been overestimated”?  Only if you think that the coral cover baseline, unlike the rest of the world, for the GBR is only ~30%: as I explained above, I think this is unlikely.

Figure 6 (From Gardner et al 2003). Absolute percent coral cover from 1977 to 2001. Annual coral cover estimates (black triangles) are weighted means with 95% bootstrap confidence intervals. Also shown are unweighted mean coral cover estimates for each year (black circles), the unweighted mean coral cover with the Florida Keys Coral Monitoring Project (1996–2001) omitted (X), and the sample size (number of studies) for each year (white circles, right y axis).

7) Other skeptic soundbites

Sweatman et al make a lot of noise about variation among reefs and subregions in coral cover trajectories and states. Basically, there is a high degree of spatio-temporal asynchrony in the system, as we discussed in Bruno and Selig and illustrated with this graphic:

Figure 7 (from Bruno and Selig 2007). Illustrative examples of asynchrony of coral cover among 25 randomly selected monitored reefs on the GBR (a) and in Indonesia (b).

This isn’t surprising or atypical and it doesn’t mean a long-term trend isn’t present or detectable, as Sweatman et al suggest. Climate change deniers use this argument frequently, suggesting that natural short term variation makes long-term, anthropogenically forced trends, unlikely or undetectable. This is in a sense what Sweatman et al are arguing as well. But the fact that there is great unforced spatiotemporal variation, i.e, noise or weather, does not mean that longer-term, human-induced change isn’t also happening. (Although this is indeed a big issue for many fields of global change science: how to detect slow, long-term trends in a sea of shorter term noise.)

Sweatman et al: A reef system that is stable in the long term will still show cycles of disturbance and recovery at a subregional scale

True, but so will a reef system that isn’t stable and is declining as has been shown for other regions such as the Caribbean (Schutte et al 2010).

Sweatman et al: In the kind of broad analysis presented here, reef resilience is manifested as substantial increases in coral cover following disturbance. In the great majority of sub- regions of the GBR, reefs showed both declines and sub- stantial periods of increasing living coral cover over the 19 years of surveys, evidence that many reefs retained their regenerative capacity.

This, I largely agree with. In fact, there isn’t much doubt that reefs on the GBR have not lost all their regenerative capacity, eg, see here.

Shifting baseline syndrome

In his classic 1995 paper in Trends in Ecology and Evolution, Daniel Pauly outlined his argument for shifting baseline syndrome in fisheries:

Essentially, this syndrome has arisen because each generation of fisheries scientists accepts as a baseline the stock size and species compostion that occurred at the beginning of their careers, and uses this to evaluate changes. When the next generation starts its career, the stocks have further declined, but it is the stocks at that time that serve as a new baseline. The result obviously is a gradual shift of the baseline, a gradual accommodation of the creeping disappearance of resource species, and inappropriate reference points for evaluating economic losses resulting from overfishing, or for identifying targets for rehabilitation measures.

The Sweatman et al paper is a great example of shifting baseline syndrome: coral reef scientists that accept as a baseline the state and coral reef cover that occurred at the beginning of their careers and use this to evaluate changes regardless of valid evidence of previously higher estimates.

In conclusion: The science certainly isn’t settled and I welcome this and future contributions by Sweatman et al and others on the matter.  I started working on this problem about 7 years ago and I frequently ask more experienced scientists and old-timers what they remember from the 60s and 70s and what they think the baseline distribution for coral cover  – which certainly varies among regions – really is.

We can’t know for sure without a time machine. But based on all the data at hand, I feel confident the GBR historically (before people starting mucking it up) had at least twice the coral it has now (including the nearshore reefs that we have lost and don’t even bother to survey anymore). This is pretty much what the vast amount of data (10,000+ surveys) for reefs around the world indicates has happened globally.

In Australia, this topic matters a lot because there has been an ongoing argument about how much the GBR has changed and how threatened it really is.  Sadly, much of this is playing out in the dodgy Aussie newspaper, the Australian. See past debunking of this nonsense about the GBR being “blue again” here, here, here, here and here.

Both shifting baseline syndrome and data cherry picking are more common in hard science and the peer-reviewed literature that you’d think. I am working on a followup post about another case of coral reef scientists playing fast and loose with the data in an attempt to support a pet idea; in this case they exclude a different set of survey data in an attempt to make the opposite point Sweatman et al did, namely to argue that reef decline is worse than has been reported. So stay tuned…

Some background and disclaimers: The lead author, Hugh Sweatman is a colleague and collaborator of mine. We have published several papers together and are working on other collaborative projects and started corresponding about coral reef baselines about five years ago. Dr. Sweatman is the director of the long-term monitoring program at AIMS (the analysis was based on the dataset from this program). I was a reviewer of the manuscript and made the same points in my signed (non-anonymous) review that I made above. Finally, Sweatman et al (2010) directly criticized findings of a paper on which I was the lead author (Bruno and Selig 2007).


Connell J.H. (1978). Diversity in tropical rain forests and coral reefs. Science, 199, 1302-1310

Endean R. (1977). Acanthaster planci infestations of reefs of the Great Barrier Reef. Third International Coral Reef Symposium, 185-191

Endean R. & Stablum W. (1973). The apparent extent of recovery of reefs of Australia’s Great Barrier Reef devastated by the crown-of-thorns starfish. Atoll Research Bulletin, 168, 1-41

Done T. (1992). Constancy and change in some Great Barrier Reef coral communities: 1980-1990. American Zoologist, 32, 655-662

Done T.J., Dayton, P.K.,  Dayton, A.E.,  Stege, R. (1991). Regional and local variability in recovery of shallow coral communities:  Moorea, French Polynesia and central Great Barrier Reef. Coral Reefs, 9, 183-192

Gomez, E. D., A. C. Alcala, and A. C. San Diego. 1982. Status of the Philippine coral reefs – 1981. Proceedings of the Fourth International Coral Reef Symposium, Manila 1:275-282

Risk, M.J. 1999. Paradise lost: how marine science failed the world’s coral reefs. Marine & Freshwater Research 50 831-837

Koch brothers now at heart of GOP power

You may remember that we posted material on the Koch Brothers.  These two billionaires have supported misinformation about the veracity of climate change on a grand scale .  Now we see their rising influence in Washington as a result of the changing political climate.  Here, the Los Angeles Times explores these changing circumstances.

The billionaire brothers’ influence is most visible in the makeup of the House Energy and Commerce Committee, where members have vowed to undo restrictions on greenhouse gases.

By Tom Hamburger, Kathleen Hennessey and Neela Banerjee, Los Angeles Times

February 6, 2011

Reporting from Washington

The billionaire brothers David and Charles Koch no longer sit outside Washington’s political establishment, isolated by their uncompromising conservatism. Instead, they are now at the center of Republican power, a change most evident in the new makeup of the House Energy and Commerce Committee.

Wichita-based Koch Industries and its employees formed the largest single oil and gas donor to members of the panel, ahead of giants like Exxon Mobil, contributing $279,500 to 22 of the committee’s 31 Republicans, and $32,000 to five Democrats.

Nine of the 12 new Republicans on the panel signed a pledge distributed by a Koch-founded advocacy group — Americans for Prosperity — to oppose the Obama administration’s proposal to regulate greenhouse gases. Of the six GOP freshman lawmakers on the panel, five benefited from the group’s separate advertising and grass-roots activity during the 2010 campaign.

Claiming an electoral mandate, Republicans on the committee have launched an agenda of the sort long backed by the Koch brothers. A top early goal: restricting the reach of the Environmental Protection Agency, which oversees the Kochs’ core energy businesses.

The new committee members include a congressman who has hired a former Koch Industries lawyer as his chief of staff. Another, Rep. Morgan Griffith of Virginia, won a long-shot bid to unseat a 14-term moderate Democrat with help from Americans for Prosperity, which marshaled conservative activists in his district. By some estimates, the advocacy group spent more than a quarter-million dollars on negative ads in the campaign. “I’m just thankful that you all helped in so many ways,” Griffith told an Americans for Prosperity rally not long after his election.

Perhaps the Kochs’ most surprising and important ally on the committee is its new chairman, Rep. Fred Upton. The Republican from Michigan, who was once criticized by conservatives for his middle-of-the-road approach to environmental issues, is now leading the effort to rein in the EPA.

Upton received $20,000 in donations from Koch employees in 2010, making them among his top 10 donors in that cycle, according to the Center for Responsive Politics.

In recent months the congressman has made a point of publicly aligning himself with the Koch-backed advocacy group, calling for an end to the “EPA chokehold.” Last week the chairman released a draft of a bill that would strip the EPA of its ability to curb carbon emissions. The legislation is in line with the Kochs’ long-advocated stance that the federal government should have a minimal role in regulating business. The Kochs’ oil refineries and chemical plants stand to pay millions to reduce air pollution under currently proposed EPA regulations.

Koch Industries is the country’s second-largest privately run company, a conglomerate of refining, pipeline, chemical and paper businesses. Their products include Lycra and Coolmax fibers, Brawny paper towels and Stainmaster carpets. Last year, Forbes magazine listed the brothers as the nation’s fifth-richest people, each worth $21.5 billion.

A spokesman for the famously press-shy family declined to comment. Koch allies say the brothers act out of ideological conviction.

A Washington energy consultant familiar with the Kochs, Javier Ortiz, said the committee agenda reflects the “needs of the American people” and a broad shift in political sentiment.

A symbolic arrival

When the 85 freshman GOP lawmakers marched into the Capitol on Jan. 5 as part of the new Republican House majority, David Koch was there too.

The 70-year-old had an appointment with a staff member of the new speaker, Rep. John A. Boehner (R-Ohio). At the same time, the head of Americans for Prosperity, Tim Phillips, had an appointment with Upton. They used the opportunity to introduce themselves to some of the new legislators and invited them to a welcome party at the Capitol Hill Club, a favorite wine-and-cheese venue for Republican power players in Washington.

The reception was a symbolic arrival for the Kochs, who have not always been close to the Republican hub. The brothers were known as hard-liners unafraid to take on conservative icons — even President Reagan and the American Petroleum Institute — whom theyoccasionally perceived to be too accommodating to liberal interests. David Koch ran as the Libertarian Party’s vice presidential candidate in 1980, when Reagan was the GOP presidential candidate.

The Kochs provided initial funding for the libertarian Cato Institute and are key donors to the Federalist Society, among other conservative organizations.

In recent years, they began drawing conservative media, business and political leaders to semiannual meetings in the West to discuss protection of the free-market ethos and to raise funds for their causes. The most recent was in Rancho Mirage a week ago.

Frustrated with the state of conservatism in Washington during the George W. Bush era, the Kochs began to shift the discussions at recent meetings from fundraising for think tanks to more specific electoral strategy.

Longtime ties

At the center of the new ground-level strategy is a beefed-up role for Americans for Prosperity. Along with other well-funded conservative groups, the group was very active in the congressional midterm election — in many cases taking on roles often performed by national and state parties.

Americans for Prosperity is the political arm of the Americans for Prosperity Foundation, which David Koch co-founded in the 1980s under the name Citizens for a Sound Economy. He is chairman of the board of the foundation, which says it aims to educate citizens on “a return of the federal government to its constitutional limits.”

Americans for Prosperity says it spent $40 million in the 2010 election cycle, organized rallies and phone banks, and canvassed door to door in nearly 100 races across the country. The organization found scores of energetic activists in the “tea party” movement to carry its message.

Throughout this effort, Americans for Prosperity kept a strong emphasis on promoting its views on climate change and energy regulation. In 2008, it began circulating a pledge asking politicians to denounce a Democratic-led effort to compel oil refineries and utilities to clean up emissions of greenhouse gases through a so-called cap-and-trade system. The organization said it amounted to a hidden tax increase.

The cap-and-trade legislation passed the House but died in the Senate. Americans for Prosperity began working to defeat House Democrats who voted for the bill, showing the power of its new activist base.

The advocacy group does not disclose spending in individual races. But it said it facilitated tens of thousands of phone calls and organized dozens of events in recent congressional campaigns. Among the beneficiaries, besides Griffith, were newly elected Reps. Cory Gardner (R-Colo.) and Adam Kinzinger (R-Ill.). All three now sit on the Energy and Commerce Committee.

Gardner and Kinzinger declined to comment on their relationship with Americans for Prosperity and the Koch brothers, although a spokeswoman for Gardner emphasized that the group’s work was “totally independent” of his campaign, in line with federal election rules.

Other committee members have deeper ties to the Kochs.

Rep. Mike Pompeo (R-Kan.), who represents Koch Industries’ home district, launched an aerospace company with investment help from a Koch subsidiary. He sold the company last year. His chief of staff is Mark Chenoweth, a former Koch Industries lawyer.

Phil Kerpen, vice president for policy at Americans for Prosperity, said the organization was pleased with the committee’s new members.

“From a policy standpoint, I think those are pretty good choices,” he said, mentioning Griffith in particular.

Griffith has questioned the EPA and the science behind its proposed regulation of global warming. “We have to be sure the EPA is reined in,” he said recently.

The Supreme Court ruled in 2007 that the EPA had the power to regulate greenhouse gases as air pollutants under the Clean Air Act. Pompeo, Griffith and others want to strip the EPA of that authority.

Until recently, Upton would have been an unlikely champion of that view.

In 2009, he told a Michigan newspaper: “Climate change is a serious problem that necessitates serious solutions.” Rush Limbaugh ridiculed Upton for his sponsorship of an energy-saving bill. Tea party groups opposed his bid for the committee chairmanship.

But as chairman, Upton said that EPA Administrator Lisa Jackson would have to attend so many hearings before his committee that she would need her own parking space on Capitol Hill. In daily e-mail blasts, he hammered at the EPA’s “job-killing” regulations.

His bluntest rhetoric against the EPA came in late December, in a Wall Street Journal commentary he wrote with Phillips of Americans for Prosperity.

The EPA’s regulation of greenhouse gas emissions, they wrote, “represents an unconstitutional power grab that will kill millions of jobs — unless Congress steps in.”

In an e-mail statement, Upton denied that his position on climate change had shifted, and he explained his work with conservative activists. “Meeting with and listening to individuals and organizations that will be affected by the laws and regulations this committee oversees is one of our fundamental responsibilities,” he said.

The change on the committee is “like night and day,” said Jeremy Symons, senior vice president of the National Wildlife Federation, a nonpartisan organization that lobbied the committee to stem greenhouse gas emissions.

“In the past the committee majority viewed the Clean Air Act as an effective way to protect the public,” Symons said. “Now the committee treats the Clean Air Act and the EPA as if they are the enemy. Voters didn’t ask for this pro-polluter agenda, but the Koch brothers spent their money well and their presence can be felt.”

Republicans wave off such comments, saying the focus on the Koch brothers is just the left’s latest conspiracy theory.

“[Former Chairman] Henry Waxman stacked the committee with liberal environmentalists,” said Rep. John Shimkus (R-Ill.), who now chairs the economy and environment subcommittee. “Now we are moving things back to the center.”

Copyright © 2011, Los Angeles Times

Severe cyclone poised to mash up the GBR and northern Queensland

Tropical cyclone Yassi is heading WSW at 21 mph with sustained winds of 140 mph and gusts to 165 mph.  This is a massive and severe store.  It is going to rock the GBR and could cause massive flooding and destruction in northern Queensland.  I hope for minimal damage to man and beast…

From ABC news:

Queenslanders have been told to prepare themselves for a terrifying 24 hours as the “most catastrophic storm ever” takes aim at heavily populated areas of the state’s north.

Severe Tropical Cyclone Yasi was upgraded to category five this morning as the weather bureau warned it was likely to be “more life-threatening” than any storm seen in Australia in living memory.

Tens of thousands of people are fleeing their homes ahead of the monster storm, which is expected to hit the coast between Cairns and Innisfail with winds of up to 295 kilometres per hour near the core.

Premier Anna Bligh says the storm’s expected landfall at about 10:00pm AEST is the worst possible news for a state which is already reeling from recent flooding.

She says Cyclone Yasi is the “most catastrophic storm to ever hit our coast”.

“Frankly, I don’t think Australia has ever seen a storm of this intensity in an area as populated as this stretch of our coast,” she said.

“Whether it’s cyclonic devastating winds, storm surge, or torrential rain further west as a result of this, we are facing an extreme event that will not be over in 24 hours, but will possibly take several days before the full flooding effect is felt across the region as well, potentially right through to Mount Isa.

“We are facing a storm of catastrophic proportions in a highly populated area. You’ve heard all of the statistics and what it all adds up to is a very, very frightening time for people and their families.

“This is not something that passes over the coast and is over in an hour. This is 24 hours of quite terrifying winds, anywhere up to 300 kilometres per hour, torrential rain, likely loss of electricity and mobile communications. People really need to be preparing themselves mentally as much as anything else.”

The weather bureau says Cyclone Yasi poses an “extremely serious threat” to life and property within the warning area, especially between Port Douglas and Townsville.

“This impact is likely to be more life-threatening than any experienced during recent generations,” the Bureau of Meteorology (BOM) said.

This morning, Cyclone Yasi was estimated to be 650 kilometres east north-east of Cairns and 650 kilometres north-east of Townsville, moving west south-west at 30 kilometres per hour.

The bureau says the low category five cyclone will continue to move in a west-south-westerly direction today, but could become a high category five before making landfall.

Senior bureau forecaster Gordon Banks says it could take at least 24 hours for Cyclone Yasi to weaken after it crosses the coast.

“There’s still potential for it to become stronger … as a strong category five we could see wind gusts in excess of 320 kilometres an hour, which is just horrific.”

He added: “If you’re bunkering down in the regions it’s going to be quite frightening and it’s going to go on and on for quite some time.”