silver plains project ~ why native? silver plains project ~ why native?

why native?

Take a look around, how many native plants do you see growing in your yard or along the street where you live? When you walk or drive to work are sidewalks edged with native plants that thrive in local soils and are adapted to fluctuations in climate; plants that require few, if any, inputs such as fertilizer and watering? Some of the plants growing around you may be native to the part of the world you’re in but most citizens of Canada and the United States don’t know the difference. In fact, the majority of people don’t realize there is a difference to be known about. For them, if it isn’t a crop or didn’t come from a garden centre it’s a weed. Few prairie dwellers, for example, have ever heard of, let alone seen, big bluestem. Yet it is the dominant grass of a once magnificent ecosystem.

big bluestem

big bluestem

western prairie fringed orchid

western prairie fringed orchid

Western prairie fringed orchid is listed as an endangered species by the Province of Manitoba and is on the IUCNInternational Union for Conservation of Nature Red List. One place the plant is trying to survive in is a highway ditch in the southeastern corner of the Province; a ditch which is used by residents of a nearby town as an ATV trail.

This perceptual state is called “shifting baseline”:Marine biologist Daniel Pauly: shifting baseline

Each generation is born into a world that was altered by previous generations. What each of us grows up with is considered normal.

For example, if Dad mowed a lawn then you are likely to do the same; in fact Dad will encourage you in this regard. If Mom (or sometimes Dad) planted a flower garden then you are likely to plant one when you get your own place. And so it goes, expanding outward to boulevards and urban parks and highway ditches.

on the yard again

The norm I (and most who read this) grew up with has a long history. Humans have been altering landscapes around their habitations for millennia. The current convention, in Canada and the United States, of expansive lawn with pocket gardens, started in Europe where the wealthy kept horses before invention of the automobile. Just one horse needs about two hectares (five acres) of grazable land annually to sustain itself. Needless to say, grass, et cetera, around estates, was generally short. Great expanses of close cropped vegetation — construed as normal — became popular among the well-to-do who started employing grounds keepers with scythes to keep vegetation short on even more hectares; this also allowed for keeping horses away from nascent lawns; the animals could be fed hay gathered by the workmen.

As settlements became established in North America, the European approach to grounds maintenance migrated across the Atlantic; well-to-do emigrés emulated their European contemporaries. The lawnmowerLAWN MOWERS, by John H. Lienhard was invented in 1830, making it possible for one person to do the work of several men (or days) in short periods of time. Anyone could have a lawn. In 1841, horticulturist Andrew Jackson Downing published an influential bookA Treatise on the Theory and Practice of Landscape Gardening, Adapted to North America, Andrew Jackson Downing; 1841 which disseminated the model to a burgeoning middle class. "Landscape Gardening" of one’s property became a requirement of life in the New World:

To hold one’s head up in respectable society one had to have a well kept lawn, ringed with flowers, dotted with shrubs or trees, all grown in a nursery somewhere nearby. (Downing owned such a nursery.)

Today, the form is ubiquitous in Canada and the United States. Yet it is common knowledge that watering lawns — especially in dry areas — is stressing or draining aquifers; that fertilizer runs off into drainage systems and then rivers, contributing to dead zones in estuaries of lakes and oceans. Fertilizers are applied to lawns because grass doesn’t grow in monocultures in the wild, and to flower gardens because plants are well-spaced in semi-isolation, dead matter is often removed and without legumes in their midst nitrogen is not fixed in the soil naturally. Most urban centres in both countries even have by-laws obliging home owners to keep their lawns cut short.Colorado State Grass Unacceptable For Garden! Cutting the grass is usually accomplished with devices and vehicles that are fueled by gasoline and require motor oil to keep them running. We humans think of ourselves as intelligent yet something that has such a negative impact on the rest of the biosphere is supported by convention and enforced by human laws.

purple loosestrife

purple loosestrife

Coincident with settlement of North America by millions of Europeans (over a few centuries) was introduction of foreign plants. Some were deliberately imported for crops or forage, many more tagged along in bags of grain, as contaminants in ship ballast, and in settlers’ belongings. The "Landscape Gardening" approach, advocated by plant vendors, promoted use of mostly imported plants. While most alien plants sold in garden centres today are well-behaved, that hasn’t been the case for all newcomers. Many have escaped and are a recurring problem in both domestic landscapes and wild areas. One egregious example is purple loosestrife which forms monocultures that squeeze everything else out, including animals and insects.

While there are many conservation and restoration projects in Canada and the US, with few exceptions, what’s growing in ditches beside highways in southern Manitoba, where I live, is ninety to ninety-eight percent introduced material. Left to its own devices, indigenous flora has lost the battle here. A new ecosystem is developing in the region. When an ecosystem is altered none of us knows when the scale will tip for each of the many species who belonged to and relied on the previous ecological community.

The native ecosystem I am familiar with is Tallgrass Prairie from the Great Plains of North America. Having traveled round the regionsoutheastern Manitoba near my home, to some original prairie remnants, I’ve noticed, in spots that rarely if ever see a mower, there are next to no alien plants. Many protected areas have stretches for parking and paths that are mowed once or twice a year and which are always littered with dandelions, clovers and the like. The reason for this seems fairly obvious:

Mowing makes the soil accessible to seed.

Dense thatch, which is the natural state for a grassland, prevents a lot of seed from reaching the soil; at least it does so when there are no herds of bison and other ungulates to press seed into the ground.

One could argue here that mowing also allows native plant seed to find soil to germinate in, but a majority of Tallgrass Prairie natives are slow starters. Most are perennials — they don’t need to propogate that much — and many have high seed dormancy. It can take several years before a seed will germinate even if conditions are optimal. Meanwhile alien plant seeds germinate immediately. Too, bare soil, which is commonplace where agriculture and horticultural gardening take place, is a ready invitation to wind blown and bird deposited seed. Whichever plant starts growing first has the upper hand in competition for resources.

Something else I’ve noticed, now that my spouse and I are planting native flora in our yard, is that many native plants take their time about sending down roots while introduced species are in a hurry. We have a couple of spots where we sowed blue grama grass seed. They previously had quackgrass (introduced) growing in them. In spite of carefully eradicating the latter before sowing the new seed, bits of rhizome remained which allowed the quackgrass to return. In a single season these rhizomes can reach up to a meter in length and are often a tangle that looks like electrical cords running this way and that just under the surface of the soil. The blue grama, meanwhile, takes more than a year before its dense, fibrous roots extend out- and downward from the seedling. I am told that quackgrass and smooth brome (which is also introduced and has similar rhizomes) was/is seeded in some areas because they prevent soil erosion during periodic flooding in the Red River Valley. But I have dug up both native and foreign plants, the former inadvertantly while removing the latter. Once established, the blue grama is extremely difficult to dig. The imports are difficult too, mostly because the rhizomes are long and abundant, but their hold on the soil is nothing compared to the native species. Consensus regarding which plants to favour would probably be different had our collective forebears done a little research. Big bluestem, mentioned above, has dense fibrous roots that can go as far down as 4.5 meters (14 feet).

While the “Landscape Gardening” or horticultural approach of neatly arranged splashes of colour delights human eyes, this practice forgets that plants in the wild grow in communities — ecosystems — that are mutually supportive of both flora and fauna. Each ecosystem, which evolved over millennia, has checks and balances that prevent some species from forming monocultures and allow all to flourish. Alien plants, though, don’t know the etiquette of new regions to which they are brought. Some have done very well in North America to the detriment of every pre-existing ecosystem on the continent.

Today, invasive alien species are the second greatest cause of extinction behind habitat destruction.

… if humans continue to combine species from different ecoregions, there is the potential that the world’s ecosystems will end up dominated by a few, aggressive, cosmopolitan “super-species”.Wikipedia ~ Biodiversity

While many birds, insects, amphibians, fish, and mammals have adapted to the changes, some species have already disappeared, many more are on the verge of disappearing, others are in decline. Without flora indigenous to ecosystems of which they are a part they are unable to survive.

Apparently we’re at the beginning of the Sixth Mass Extinction, the first one caused by a lifeform:

By the most pessimistic estimates, if the current rate of extinction continues, we could wipe the planet clean in the next hundred years. And since we depend on other life for food and medicine, I guess that scenario involves wiping ourselves out as well.Bob McDonald ~ CBC ~ International Year of Biodiversity

Many disregarded indigenous plants were, and still are, used for medicinal purposes:

purple coneflower, primrose, golden alexander, three flowered avens, black-eyed susan, blue-eyed grass, blue flag iris, purple prairie clover, gaillardia, grass of parnassus, common milkweed, showy milkweed, little leaved pussytoes, red columbine, seneca root, smartweed, nuttall’s sunflower, wild licorice, and prairie rose.

All of the foods we grow as crops, from grains to cucumbers, started as wild plants. Corn, a staple of the North American diet, originated as wild maize in what is now northern Mexico. The following are some of the native plants that sustained aboriginals before the arrival of Europeans:

purple prairie clover, brackenfern, silverweed (also kept many early settlers of the Great Plains alive on first arrival), smooth camas, narrowleaf sunflower, junegrass, prairie dropseed, sloughgrass, witchgrass, common cattail, baltic rush, fireberry hawthorn, and prairie rose.

Indigenous flora also provides a number of services:

Not that long ago it was possible to drink water from most North American streams and lakes. But one of the first things settlers of the continent did, after tilling the readily usable land, was to drain or alter wetlands (swamps, bogs, fens). In addition to the debilitating effects this had on regional fauna, the practice reduced or eliminated the capacity of these natural filters to store and clean water as it drains into waterways and is absorbed into aquifers below the earth. Wetlands remove heavy metals and other contaminants from water.paraphrased from McGill University Biodiversity website

While not the case for all native ecosystems in Canada and the United States, the Tallgrass Prairie of the Great Plains had some of the richest soil on the planet. Millennia of manure from grazing ungulates, deadfall decomposition, and the effects of fire produced a layer of clay loam mix on top of a bed of clay that retains water. (Prehistoric Lake Agassiz once covered most of the region.) The combination of fertile soil and moisture retention makes for fantastic growing conditions. One could say that the soil’s strength has been the former ecosystem’s downfall:

Just about all of the Great Plains has been tilled and turned into farmland or is covered by cities and towns and roads.

Continent-wide, reduction of habitat, deliberate or inadvertant planting of alien species, mowing (which favours alien species), and disturbed soil (which also favours the aliens) has had a devastating effect on indigenous flora and the fauna it supports.

In most regions of Canada and the United States, various levels of government protect different tracts of land from the encroachment of humans. They have been marginally successful at this; many parks and preserves are also popular tourist destinations. Unfortunately, for species other than our own, protected areas are separated by sprawling urbanity and criss-crossed with stretches of pavement; high speed vehicles are an added hazard for fauna who need to get from one side of a road to the other.

Tallgrass Prairie Preserve

Tallgrass Prairie Preserve

Agassiz Interpretive Trail

Agassiz Interpretive Trail

Near the southeastern corner of Manitoba, by Tolstoi and Gardenton, there are remnants of virgin Tallgrass Prairie only because the area is littered with boulders left behind by a retreating glacier; it was too much work to clear it, to make it over into fields of grain, and because Ukrainian settlers of the area thought it was a good idea to regularly burn the grasslandHad they not done this the area would have filled in with trees; today it would resemble the Aspen Parkland.. This distinct ecosystem had covered a sizable portion of the province in 1870. By the late 1980s — when an area that had never seen the plow was discovered — only 1% remained. But,

only 1/20th of 1% of the original Tallgrass Prairie remains today. A part of even that tiny remainder is plowed up and paved over every year.John P. Morgan of Prairie Habitats.
John, along with Marilyn Latta and Manitoba Naturalists Society (now Nature Manitoba), started the Tall Grass Prairie Inventory project in 1986/87. This group identified what is now the Tallgrass Prairie Preserve and initiated the Tallgrass Prairie Conservation Project.

Manitoba ~ extent of Tallgrass Prairie c 1870:
6,000 square kilometers

remaining Tallgrass Prairie c late1980s:
30 square kilometers

One has to wonder why previous generations didn’t choose to integrate themselves into local ecosystems. It’s a lot of work to put in lawns and gardens, to drain and fill in wetlands. Many settlers, history books tell us, were fleeing religious and political tyranny; they were miserable in the Old World; they were looking for a new life, a new way of living. Yet they ended up mimicking so many forms and norms from the places which they fled.

A comment from a local farmer comes to mind as I wrap this up:

“If only we could get rid of the weeds,” he said.
“That’s easy,” I responded. “Stop mowing!”

It’s not as simple as that, to be sure. But mowing is one activity, that we all do, which fosters the growth and spread of alien plants we all call weeds, that we all seek to eliminate. Were we, in southern Manitoba, to stop thinking of indigenous flora as weeds, to stop mowing everywhere, and to replant yards and highway ditches with native species, many side benefits would accrue:

• Considerable time would be freed up,
• less petroleum would be burned,
• a source of noise polution would be gone,
• application of fertilizer would be reduced or eliminated, and,
• because native flora will not encroach on farmers’ fields as quickly or as much as do all the introduced species that currently dominate highway ditches, use of chemical herbicides would be reduced (if not done away with).

What I advocate here (and many others do as well) is easier said than done. I know, from first-hand experience, how much work is involved to replant one small parcel of land with native flora. The work is made harder by a simple numbers game:

Currently seed in the soil and air of unwanted alien plants vastly outnumbers seed from the natives we are trying to get established.

Were this reversed, were the alien plants displaced, all be it eventually, then it might actually happen one day that we could spend a summer just enjoying the native flora and the fauna it attracts; the park, if you will, would be right outside our door(s).

And there’s an ancilliary benefit:

Other species, which are adversely affected by our current ways, could go about their business.

The baseline for future generations would shift in a positive direction.

Robert G. Mears

August 2010