Our Better Half: Examining Mass Extinction in Nova Scotia

The concept of biodiversity is relatively new to the mainstream, proposing that ecosystems can be appraised, so to speak, based on the variety of organisms they support. It states simply that a healthy forest cannot contain solely Balsam fir, nor a healthy river exclusively Atlantic salmon.

There must be multitudes of interconnected and interdependent living things, it states, their diversity allowing for greater adaptability and resistance to change, more productivity in the creation of clean air, water and soil, and swifter recovery from losses sustained. No single species can be taken by itself, only as part of a greater whole.

And the “whole” in question is immense. To date the scientific community has described something like 2 million multicellular species and many suspect another 6 million await their page in our textbooks, if not more.

Growing in stride with our understanding of biodiversity, however, has been its loss across the global, even here in Nova Scotia. Since European settlement we’ve eradicated the Great auk, Sea mink, Atlantic walrus, Passenger pigeon, Eelgrass limpet and Labrador duck from our small province, alongside species which can still, mercifully, be found elsewhere. Today our Atlantic whitefish and Boreal Felt lichen are on deck. Taken all together, these ongoing extinctions here and abroad suggest a mass extinction event, where loss begets loss until the entire system collapses, known to have occurred only five times in all of natural history.

The Sixth Mass Extinction, as this most recent trend is being called, is difficult to comprehend, especially on the local level. Speaking personally, I tend to focus on individual species-at-risk rather than face this problem in its entirety, threatening, as it does, the fundamental ecology on which we humans depend.

Late this summer I sought the expertise of Dr Tom Herman who, in his 36 years at Acadia University and in the field, has honed an extraordinary understanding of our biodiversity and its hastening decline. With facts, figures and considerable insight, he allowed me to appreciate this issue fully for the very first time.

Barred owl
Shown above is a Barred owl.
Zack Metcalfe photo

Extinction by the Numbers

Some people try dismissing extinction as a natural phenomena, something our biosphere has dealt with since its conception, but in this case, whether something is in fact “natural” has to do with its frequency, and context.

Our planet’s background rate of extinction – that is, “natural” extinction – is between 1-10 species per million per year, Tom explained. So even on the scale of natural history, extinction is rare, caused by climatic, geologic or biological shifts which certain species are unprepared for. Our modern rate of extinction, however, is about one thousand times higher than that background rate, a frightening estimate Tom believes to be conservative if anything.

“The loss of habitat is absolutely key,” said Tom, exposing this most potent driver of extinction. Climate change, excessive hunting, pollution and the rest are without doubt doing their part, but the loss of our wildest places to unsustainable forestry, agriculture, development and urban sprawl imperils these species most of all.

This makes the protection of terrestrial ecosystems indispensable in our prevention of mass extinction, but oddly enough, this relationship between land and biodiversity is not a linear one. In rough figures, Tom said that if a region losses 90 per cent of its natural spaces, it will lose 50 per cent of its species. Given that only 15 per cent of lands globally – shy of 13 per cent provincially – are under some form of protection, Tom said we’re closer to this calamitous scenario than is ideal.

“Alternatively, if we randomly protect 50 per cent of the planet, we will preserve about 85 per cent of its species,” he said. “If we targeted particular areas for protection in that 50 per cent, however – so-called biodiversity hotspots – we could improve that 85 per cent.”

Nova Scotian Old Growth
Shown above is Nova Scotian old growth forest.
Zack Metcalfe photo

Hotspots on the Homefront

When one imagines a biodiversity hotspot, the rainforests of Ecuador are a popular choice, but because life is as diverse as the regions which support it, all peoples have a responsibility to their corner of the planet. Even humble Nova Scotia contains biodiversity hotspots of global significance.

Tom made particular note of the southwestern disjuncts, a collection of species separated from their counterparts elsewhere in North America by our province’s semi-island status. They arrived in Nova Scotia during a climatic warming period some 6,000 years ago and have been trapped by the returning cold ever since, adapting differently to our region and offering a new exit off the evolutionary highway. Among these are the Blanding’s turtle, Eastern ribbonsnake, Southern Flying squirrel, fifty species of coastal plain flora and several insects.

Then there are the northern disjuncts of Cape Breton Island, species which would traditionally be comfortable farther north but have adapted to our province out of necessity, unable to leave. These include some shrews and several plants.

Of course there were other examples of Nova Scotia’s uniqueness, such as our unusual concentration of continental dragonflies, but suffice it to say, there’s a great deal here in need of protection under the aforementioned 50 per cent.

Defining Protection

Modern protection takes the form of a park or wilderness area in which our influence is restricted to “take only pictures, leave only footprints,” but when viewed through the lens of biodiversity, protections going forward demand a new approach.

Tom stressed his love and commitment to core protected areas across Nova Scotia, such as Kejimkujik National Park and the Tobeatic Wilderness Area, but while such places are indispensable to the protection of Nova Scotia’s biodiversity, they’re not enough.

There are two traps we fall into when depending solely on traditional protected areas, said Tom. The first is that these lands don’t tend to give species enough space, preventing their free movement across the province, even beyond protected border. If surrounding “unprotected” lands are still subject to the full force of human disturbance, all these parks and wilderness areas have done is herd our biodiversity out of the way, creating what Tom described as “postage stamps” of suitable habitat.

“If we create these islands of habitat then pretend we’ve protected their biodiversity, what happens when the climate changes and that entire island becomes uninhabitable for any particular species? Where does it go?” he said. “So protection of an area does not necessarily afford protection to the biodiversity within it.”

And climate change isn’t the only peril threatening those postage stamps. Consider the 1-in-100 year storm which could level its foliage, the rare wildfire whipping this habitat clean, the necessity of gene flow between two populations stuck in separate postage stamps. These areas of core protection need to be large and connected in order to effectively house biodiversity.

The second trap presented by core protected area, as suggested above, is that they abdicate our responsibility to the unprotected lands surrounding them, as though our safeguarded 13 per cent makes the remaining 87 per cent fair game. This, of course, can’t be the case when striving for 50 per cent protection.

“I’m not naive enough to suspect that we’re going to put a fence around 50 per cent of Nova Scotia and say, ‘this land is off limits,’ but we need that 50 per cent for biodiversity. So we need to change our behaviour in those spaces. We can’t carry out our present or historic approaches to forest management on that 50 per cent because it will degrade the environment for much of biodiversity. But does that mean we can’t manage forests in that 50 per cent? Of course not. What it means is that we have to place paramount importance on biodiversity and its wellbeing in that 50 per cent.”

I’ve heard this sentiment before, from some very intelligent people who have no desire, and see no need, to erect a hypothetical fence around 50 per cent of Nova Scotia. It’s only necessary to manage that 50 per cent in a way which prioritizes biodiversity. In the case of forestry, I’ve heard it suggested that we could rely more on selective harvests than clearcuts, maintaining the forest’s canopy and maturity, both of which biodiversity depends upon. The goal is to co-existence with biodiversity, not abstain from it.

It’s a powerful idea, managing lands surrounding our core protected areas in this gentle fashion, an undertaking considerably more practical and affordable than declaring half of Nova Scotia a provincial park. But what would it look like? I asked Tom how you would manage the sprawling farmland of the Annapolis Valley for biodiversity, a region altogether beautiful, productive, yet decidedly tamed.

“Hedgerows,” he said simple, an allowance of growth between fields, tempering the wind and allowing for the settlement of certain species, such as the bees on which pollination depends. There are countless methods of incorporating nature into human spaces, said Tom, some requiring a change in mindset, even machinery, but none prohibiting land use outright.

Eastern ribbonsnake
Shown above is an Eastern ribbonsnake.
Zack Metcalfe photo

Checks and Balances

I’ve been told not to mention 50 per cent protection out loud, at least not in reference to tiny Nova Scotia. It can sound like an impossible feat to the uninformed, made especially sad by the unwillingness of extinction to negotiate. I have faith, however, that once brought up to speed on its importance and appearance, 50 per cent will seem doable to your average Nova Scotian. We don’t have to give up these lands in order to protect them, only consider their needs in advance of our own. It’s a leap in priorities which we must achieve in order to stave off mass extinction here and afar, a leap we’re more than capable of.

Zack Metcalfe is a freelance journalist, author, and writer active across the Maritimes. This article was originally published with Rural Delivery Magazine.

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