Cli­mate change aids in­va­sive species


It’s un­clear how many peo­ple in New­found­land and Labrador know the name Mem­bra­ni­pora mem­branacea — cof­fin box.

It is an in­ver­te­brate, a bry­ozoan, a tiny fil­ter feeder that at­taches it­self to things in the wa­ter and builds up into rough mats, colonies. It’s not ex­actly wel­comed.

“It tends to form very thick crusts on the sur­face of kelp and th­ese crusts in­ter­fere with some key bi­o­log­i­cal as­pects of the seaweed,” said Pat Gagnon, with Me­mo­rial Uni­ver­sity of New­found­land’s de­part­ment of ocean sciences, who has stud­ied the bry­ozoan in New­found­land and Labrador.

Apart from lim­it­ing the kelp pho­to­syn­the­sis, it lim­its its re­pro­duc­tion and, by adding weight to the blades, can re­sult in the seaweed break­ing off in heavy waves.

“That’s biomass that’s no longer avail­able for other species that de­pend on kelp,” he said.

Gagnon men­tioned the cof­fin box when asked about what he sees re­lat­ing to cli­mate change in New­found­land and Labrador. The species popped up on the U.S. At­lantic coast, and was recorded in Nova Scotia by the 1990s. A pa­per pub­lished in 2012 in Marine Bi­ol­ogy, au­thored by Gagnon and Scott Caines, ad­dresses the im­por­tance of wa­ter tem­per­a­ture for its pro­lif­er­a­tion. The pa­per fol­lowed their ex­am­i­na­tion of kelp sam­ples and tem­per­a­ture read­ings taken from eight sites, on a north-south range of 450 kilo­me­tres along west­ern New­found­land and the south of Labrador.

“You only re­ally need to have an idea of the tem­per­a­ture pro­file at one site to be able to pre­dict how much of that bry­ozoan you get on the kelp. So there’s a very strong re­la­tion­ship be­tween the tem­per­a­ture and the abun­dance,” Gagnon said.

De­spite its name, de­spite its pres­ence here af­ter hav­ing al­ready de­stroyed en­tire kelp forests in the Gulf of Maine, ac­cord­ing to the De­part­ment of Fish­eries and Oceans, Gagnon doesn’t talk about the cof­fin box as be­ing good or bad. They just are.

If the tem­per­a­ture is right and they can spread and col­o­nize, they will.

“It is ex­pected that ocean warm­ing will trig­ger range ex­pan­sion in many marine in­ver­te­brate. There­fore, a corol­lary hy­poth­e­sis is that kelp habi­tats at the south­ern and north­ern tips of New­found­land and in Labrador will be in­creas­ingly at risk as sea tem­per­a­ture con­tin­ues to rise and growth con­di­tions be­come more favourable for Mem­bra­ni­pora mem­branacea,” the pa­per stated.

Look­ing to land, the Na­ture Con­ser­vancy of Canada (NCC) main­tains a gallery of in­va­sive species to Canada.

NCC na­tional con­ser­va­tion bi­ol­o­gist Dan Kraus said not all in­va­sive species are a nui­sance or harm­ful, but some are. And plenty are al­ready here to stay.

“Prob­a­bly one of the best things we can do is, first of all, use it as a les­son and think about how they got here and how we can keep oth­ers from com­ing in,” Kraus said.

The aware­ness is even more im­por­tant, he sug­gested, as cli­mate change af­fects long­stand­ing nat­u­ral bar­ri­ers, like the one keep­ing kudzu — “the vine that ate the South” — from in­vad­ing.

A patch was spot­ted in south­ern On­tario in 2009.

“It can grow very rapidly and take over huge ar­eas and it hadn’t been able to grow in Canada be­cause of our win­ters, but there’s an ex­am­ple of a plant where, be­cause of warm­ing cli­mate, it could start to get es­tab­lished,” he said. “There’s ac­tu­ally quite a few species like that, where us­ing cold against an in­va­sive species maybe isn’t as ef­fec­tive as it used to be in Canada.”

With im­proved reg­u­la­tions around ev­ery­thing from bal­last wa­ter to nurs­ery plants, Kraus said there is gen­eral im­prove­ment in pre­ven­ta­tive mea­sures against new in­vaders.

How­ever, in­di­vid­u­als should be aware their own ef­forts can make a dif­fer­ence. He pointed to an ag­gres­sive re­sponse by gov­ern­ment af­ter re­port of a snake­head fish in a pond in Bri­tish Columbia and the pro­gram in On­tario to erad­i­cate the Asian longhorned beetle.

“I think cli­mate change, it means we re­ally have to dou­ble down on our vig­i­lance,” Kraus said. “So hav­ing an in­formed pub­lic out there so when they see some­thing they can hope­fully help iden­tify and re­port it, so we can man­age it quickly.”

He rec­om­mended try­ing the app inat­u­ral­ist (inat­u­ral­ to help iden­tify and map species you spot, all with the snap of a pic­ture.

But there are species al­ready ar­rived where dis­rup­tion will have to be man­aged.

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