Get­ting reef back

Port Douglas & Mossman Gazette - - CLASSIFIEDS -

SHOCKS caused by cli­mate and sea­sonal change could be used to aid re­cov­ery of some of the world’s badly de­graded coral reefs, an in­ter­na­tional team of sci­en­tists has pro­posed.

A new re­port by Aus­tralian and Swedish marine sci­en­tists in the jour­nal Fron­tiers in Ecol­ogy and the En­vi­ron­ment sug­gests that it may be pos­si­ble to restore liv­ing coral cover to a badly-de­graded reef sys­tem - though not easy.

With 70 per cent or more of the world’s coral reefs now as­sessed as de­graded, adopt­ing a busi­ness-as-usual ap­proach to how we use and man­age reefs is no longer an op­tion, says lead author of the re­port Dr Nick Gra­ham from the ARC Cen­tre for Coral Reef Stud­ies and James Cook Univer­sity.

‘‘We are un­likely to be able to keep many of the world’s reefs in a pris­tine state, but with good man­age­ment we may be able to main­tain them in a coral­dom­i­nated con­di­tion and in some cases we may be able to bring back reefs from a de­graded state,’’ he said.

The re­searchers have taken heart from ex­am­ples on land in de­ser­ti­fied land­scapes; ex­cep­tional falls of rain, in com­bi­na­tion with con­trols on graz­ing pres­sure, can re­sult in wide­spread re­growth of nat­u­ral veg­e­ta­tion.

They ar­gue that coral reef man­agers may be able to take ad­van­tage of shocks like trop­i­cal storms, pe­ri­ods of cloudy weather or even strong sea­sonal ef­fects on abun­dance to restore coral cover on de­graded reefs.

‘‘Nor­mally we think of th­ese shocks as dam­ag­ing to coral reefs - but re­search sug­gests they are just as dam­ag­ing to the or­gan­isms that can re­place coral. In other words they may act as a cir­cuit- breaker that al­lows corals to re­gain con­trol of a reef.’’

The key to the new think­ing is re­silience: healthy corals reefs are nat­u­rally re­silient to shocks - but dam­aged ones may be­come over­grown with sea weeds, and the corals van­ish.

‘‘ Weed- dom­i­nated sys­tems are pretty re­silient too and, once es­tab­lished, it is very hard to restore the corals,’’ Dr Gra­ham ex­plains.

‘‘How­ever a weed-dom­i­nated reef can be dam­aged by big storms too. Cloudy weather and sea­sonal changes in wa­ter tem­per­a­ture can also cause the weeds to die back.

‘‘This dieback of weeds opens a win­dow through which corals can re-es­tab­lish.’’

The key to bring­ing back corals is ex­actly the same as pre­vent­ing coral cover be­ing lost in the first place, Dr Gra­ham says - re­duc­ing hu­man im­pacts through reg­u­la­tion of fish­eries and wa­ter qual­ity.

If reefs are pre­pared in this way, they may bounce back when a win­dow for re­cov­ery opens.

Prof David Bell­wood from the Cen­tre and JCU em­pha­sised that ‘‘when it comes to sav­ing our coral reefs, preven­tion is al­ways bet­ter than cure and early ac­tion is im­por­tant to slow or re­verse degra­da­tion’’.

The re­searchers em­pha­sise that both pro­tec­tion and re­cov­ery of the world’s coral reefs call for a fun­da­men­tal change in how peo­ple in­ter­act with and use reef ecosys­tems.

‘‘ Un­til now the fo­cus has mainly been on con­serv­ing small parts of a reef in marine pro­tected ar­eas, said Prof Bell­woodwe’re talk­ing about broader ap­proaches to change the re­la­tion­ship be­tween hu­mans and coral reefs to re­duce hu­man im­pacts across the whole ecosys­tem."

The pa­per con­cludes, ‘‘Al­though the com­po­si­tion of coral reefs will likely con­tinue to vary over time, it may be pos­si­ble to main­tain coral-dom­i­nated reefs and their as­so­ci­ated ecosys­tem goods and ser­vicesS­ci­en­tists and man­agers could take ad­van­tage of op­por­tu­ni­ties for change by har­ness­ing shocks and nat­u­ral vari­abil­ity as po­ten­tial stim­uli for ben­e­fi­cial shifts in ecosys­tem states.’’

The pa­per, ‘‘Man­ag­ing re­silience to re­verse phase shifts in coral reefs’’ by Nicholas AJ Gra­ham, David R Bell­wood, Joshua E Cin­ner, Terry P Hughes, Al­bert V Norstro¨ m and Mag­nus Nys­tro¨ m ap­pears in the jour­nal Fron­tiers in Ecol­ogy and the En­vi­ron­ment.

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