Ups and downs

I haven’t blogged for many months. I’m sure most will understand when I say ‘there have been a myriad of reasons’ for my yap gap.

My last post was – posted – before the Covid madness had descended. The pandemic has changed every-bodies lives, everywhere in the world and continues to do so.

There’s a lot of talk about what the new normal is going to be, the one that emerges after all this period of change settles down, but who’s to know when that will be, or what it will look like. A phrase that I keep going back to is one about how the only constant in our lives is change. Every day is a new day, also comes to mind.

Except for a swath along the equator, most of the world sees constant, seasonal change. Even equatorial regions have alternating wet and dry seasons. No two seasons are ever exactly the same, although patterns and trends may be clearly evident.

Since my last posting, the ice and snow that covered our field, marsh and forest has melted away, replaced by many shades of mostly greens. A blue pond now compliments the summer skies. Goslings and ducklings have come to be and fawns now need be aware of bears as well as wolves. It’s summer!

Anyway, thoughts about the consistency of change that comes with the seasons is an underlying premise of this blog. Things are always different than they used to be, although trends are clearly evident..

The posting has been published. It’s my latest column in Ontario Out of Doors magazine. 

As per my practice, the posting is the unedited version of the column. I know the two are always a bit different, but I seldom compare the two and if I do, it’s only a very cursory look. Editors edit – that’s their job and most are good at it.

I’ll keep posting. There was a time when I posted about once a week – well, I can’t do that anymore.

Until next time, stay safe.

 

What Goes Up, Does Come Down

By: Bruce Ranta

I heard the hunter before I saw him. When we met on the trail, he looked at me, somewhat perplexed, then blurted out “They’re extinct!”

We were hunting moose – moose weren’t ‘extinct’, of course, but it did seem that way. Neither of us had seen a fresh track or any other sign of moose.

Unfortunately, the lack of moose didn’t surprise me. Moose on my stomping grounds close to my Kenora home had been on a steep decline for several years – and not just where I liked to hunt. Moose populations had been on a similar downhill slide in much of northwestern Ontario, neighboring Manitoba and Minnesota, as well as further afield, in places like Vermont and New Hampshire.

What was going on?

There were many theories. To sort it through, Dr. Murray Lankester, a parasitologist with Lakehead University and I analysed data pertaining to moose and deer in the Kenora area going back, in some cases, over 100 years. We concluded that several factors were driving forces behind moose (and deer) population fluctuations.[i]

For one, we found that both moose and deer populations surged in the aftermath of large, landscape scale disturbances, namely fires, large blowdowns, clear-cut logging and spruce budworm epidemics.  Deer abundance was also tied to winter severity – long, cold and snowy winters knocked deer down – short winters without much snow saw big upticks in deer numbers.

In the 1990s, deer and moose numbers swelled in tandem. Winters were mild and food was abundant. Even a bad winter in 1995 didn’t have much of an impact on deer – the woods were full of easy to reach and nutritious arboreal lichens growing on millions of balsam trees killed by a spruce budworm outbreak. The same thing had happened 40 years earlier.

When deer became super-abundant, moose numbers began to plummet. Brain worm appeared to be a factor. The parasite has no discernible impact on deer, but is deadly on moose. When deer densities get above 4-5 deer/km2, the disease becomes problematic to moose.

Deer densities rose to at least twice that level.

Exacerbating the problem was the weather – a series of wet summers made conditions ideal for terrestrial snails and slugs, the brainworm’s conduit for the disease.

High deer numbers also led to skyrocketing wolf numbers.

The quantity and quality of moose browse declined precipitously with a slowdown in logging and the maturing of burns and blowdowns.

In short order, the moose population crashed.

Deer eventually depleted the supply of arboreal lichens. Winters turned cold and snowy. Wolves were everywhere. Deer too, crashed.

Today, there aren’t a lot of moose or deer in much of the Kenora area (except in the city where deer are relatively safe from wolves and people feed them).

With deer numbers down, will the moose recover?

Maybe, although with only low levels of logging and no recent large forest fires or blowdowns, moose habitat is presently sub-optimal.

Deer have continued their downward spiral owing to a spate of snowy winters and continued predation by wolves. With few deer, wolves will eventually crash. Then, with at least a few mild winters – deer might stage a comeback. The next spruce budworm epidemic will help, but that’s still a few years off (budworm outbreaks occur about every 40 years).

The fact is, ups and downs are normal in many populations of wildlife.  Stable populations, especially in seasonal climates, are the rarity.

What happened in the Kenora area isn’t exactly why moose – or deer – numbers have gone up or down elsewhere. Still, there are parallels and commonalities.

Food availability is commonly linked to population changes, as is weather, the abundance of predators and human hunting pressure. Diseases are also problematic, especially during population peaks.

Across North America, some populations of barren ground caribou have recently shown dramatic declines. Although somewhat alarming, it’s not unprecedented. Northern herds have a history of spectacular ups and downs. In Alaska, the caribou population dropped by more than 50% in the late 1970’s. In Quebec/Labrador, the caribou population jumped from less than 200,000 in the late 70’s to around 1 million in just 20 years. They have recently plummeted to only a few thousand.

In winter, caribou eat lichens, a very slow-growing plant, almost exclusively. Although over-grazing lichens isn’t the only issue they face (wolves, hunting pressure, disease and parasites and the weather are also important), food does matter.

After being reduced to paltry numbers (and extirpated in eastern Canada), wild turkeys, aided by re-stocking and re-introductions, underwent a huge expansion in range occupancy and population. But in the USA, turkey numbers peaked about a decade ago, and have since declined – again, not unexpectedly – ‘new’ or reintroduced populations often flourish, subside, then have years of – you guessed it – ups and downs.

While wildlife population ups and downs can’t be curtailed, they can be managed.

As OFAH Wildlife Biologist Keith Munro says, “We really need to take a big picture approach to wildlife management. Rather than focusing on a single factor that may be affecting a wildlife population, we need to consider the whole system which includes, but is not limited to, harvest (both licenced and rights-based), predation, competition between species, diseases, parasites, and habitat”.

But no matter what we do, what goes up – does come down.

[i] To read the entire study, see Ranta, B., and M. W. Lankester. 2017. Moose and deer population trends in northwestern Ontario: a case history. Alces 53: 159–179. https://alcesjournal.org/index.php/alces/article/view/227)

 

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