The glass grass

The attitudes and practices of colonialism did incalculable damage, and not least on the list is the fact that (by and large) the colonizers completely disregarded indigenous people's knowledge of their own lands.

The inevitable result was that much of that knowledge was lost.  Not only general, broad-brush information such as how to raise food in climates unfamiliar to the colonial cultures, but specific details like the uses of native plant and animal species.  The colonizers, secure in their own arrogance, instead imported the species they had back home -- thus adding another problem on top of the first.

Because, of course, this is a huge part of why there's such a problem with invasive exotics.  Some jumped accidentally; but a great many were deliberate imports that have proceeded to wreak havoc on native ecosystems.  Consider, for example, the problems caused by the introduction of European rabbits to Australia -- and the millions of dollars that have been spent since trying to control them.

I bring up Australia deliberately, because it's a prime example of colonizers completely ignoring millennia of experience and knowledge by indigenous people, embodying Adam Savage's oft-quoted line "I reject your reality and substitute my own."  You'd think they would have listened, wouldn't you?  Not only does Australia have a tough climate by most anyone's standards, plagued by droughts and floods that seem to alternate on a monthly basis, its native species have adapted by becoming tough and resilient.  The indigenous Australians managed in much the same way; learning how to deal with the climate's vagaries -- and relying on the native plants and animals to provide sustenance.

This meant making use of damn near everything, including species that seem on first glance to be worse than useless.  Take, for example, spinifex grass (Triodia spp.), which grows all over inland Australia.  Not only is it able to survive in broiling hot desert conditions -- it can survive temperatures of 60 C -- it puts down roots as long as thirty meters in an attempt to access what groundwater there is.  In a place where any kind of vegetation is fair game for herbivores, spinifex has developed ways to defend itself; it absorbs silica from the soil and deposits it in the tips of the leaves.  Silica, I probably don't need to point out, is better known as glass.

Walking through a field of spinifex in shorts is a good way to come out with your legs embedded with thousands of glass splinters.

An Australian grassland ecosystem, with two species of spinifex -- the green plants are soft spinifex (Triodia pungens), and the gray-green ones are lobed spinifex (Triodia basedowii). [Image licensed under the Creative Commons Hesperian, Triodia hummock grassland, CC BY-SA 3.0]

Despite its difficulties, the indigenous Australians made full use of this odd plant.  The fibers of the stems were used for weaving and thatching huts; the waxes and oils extracted from it were hardened into a resin that could be used as a glue or a sealant.  And now, spearheaded by the Indjalandji-Dhidhanu people of the upper Georgina River, spinifex is being reintroduced as a 21st-century commodity -- with potential international markets.

Scientists at the University of Queensland, working with Indjalandji-Dhidhanu elder Colin Saltmere (himself an adjunct professor of architecture), have analyzed spinifex's unique properties, and found that not only does the resin (used for thousands of years by indigenous peoples) have properties similar to moldable plastic, the fibers in the stems have high flexibility, exceptional resistance to fatigue cracking -- and eight times the tensile strength of an equal diameter of steel.  The potential applications are already a very long list, including cable manufacture, production of resilient membranes (possibly superseding latex in gloves, for example), and creation of substitutes for wood, plastics, and carbon nanofibres.

"For thousands of years, spinifex was a building block for the Aboriginal societies in the desert; now it will continue to play a role in advancing local Aboriginal communities through business and employment opportunities," Saltmere said.  "The fine fibres at a nanoscale make this plant remarkable – and because it is so fine, we can make a fully renewable gel that is 98% water, and on a scale where we can sustainably generate hundreds of thousands of tonnes of material."

What seems to me to be nothing more than common sense -- "Listen to the people who know the land way better than you do" -- was effectively ignored for hundreds of years.  It's heartening that at least some of those voices are now being heard.  And given what's happening to the climate, we're going to need every advantage we have.  Better late than never, I suppose.  In this case, making use of a strange crop that was considered little more than a weed by the European colonizers, the multiple uses of which are only now becoming wider knowledge outside of the communities of indigenous Australians.

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Meadow management

My wife and I live on a 3.5 acre bit of land in the hills of upstate New York.  We're lucky to have that kind of space, and the place itself is beautiful; it's crossed by a little stony-bedded creek, and has a swimmable pond and lots of big old trees for shade.

And lots of lawn.  At least it did when we moved in here eighteen years ago.  We've been gradually doing battle with the lawn for most of that eighteen years.  We replaced some with gardens -- which was a net loss of discretionary time, since weeding a garden takes a great deal more time than mowing an equal-sized piece of lawn.  My wife got the idea of replacing a lot of the grass in the back yard with clover, and she was helped out in that endeavor by our large galumphing dog Guinness, who essentially does a hockey stop whenever he's chasing his tennis ball, tearing up large strips of turf and thus earning himself the nickname "Skidmark."  But the clover's finally taken hold in a big way, and it not only looks great and needs way less mowing, it's a happy place for the honeybees.

That last bit was our incentive for turning a chunk of our front yard into a meadow.  A wonderful local nursery, The Plantsmen, specializes in native wildlife-friendly plants, so a couple of months ago we went down and came back with my Honda Element packed with such unusual finds as blue-stemmed goldenrod (Solidago caesia), nannyberry (Viburnum lentago), American scarlet elderberry (Sambucus racemosa), two different kinds of bergamot (Monarda spp.), fragrant sumac (Rhus aromatica), serviceberry (Amelanchier canadensis), and in a corner that has a permanent spring, the charming and water-loving buttonbush (Cephalanthus occidentalis).

The Meadow thus far.  Okay, it doesn't look like much yet, but just you wait until our plants have a couple years' growth behind them.

The reason this topic comes up is because of a study that came out this week in the journal Biological Conservation about the role of verges in preserving valuable pollinators and beneficial insects.  Verges, they tell us, are hotspots for flowers and pollinators, often containing a dramatic diversity of different species (not all of which are native, of course; but then, neither is the white clover we seeded in our back yard, and I still consider it to be on balance a beneficial plant).  

Of course, roads themselves are a necessary evil, replacing and fragmenting habitat, not to mention the never-ending problem of roadkill.  (Don't just think of mammals, here; think of the number of insects killed yearly by windshield collisions, and keep in mind that even the National Pesticide Information Center says that 97% of insect species are neutral with respect to humanity, or else actively beneficial).  So given that roads aren't going anywhere, the best thing to do is to figure out how to maximize whatever's positive about them, and minimize the negative ecological impact.

Verges seem to be the biggest positive feature, as long as they're managed properly.  The key, says the researchers (a group led by environmental scientist Benjamin Phillips of the University of Exeter), is to mow as infrequently as is practical for the spot.  Surprisingly, "don't mow at all" turns out to be a bad idea.  The authors write:

An observational study of 19 road verges in the UK found that mown verges (cut once between May and August, cuttings not removed) had on average 67% fewer flowers and 61% fewer pollinators across the summer than unmown verges, experimentally manipulated mowing frequency (cuts/year: 0, 1 (early autumn) or 2 (early summer and early autumn)) and removal of cuttings (left in the verge or removed) in a single road verge (with a species-rich plant community) in the Netherlands.  Increasing the number of cuts from 0 to 1 cut resulted in 3.5 times greater flower density and 2 times greater flower species richness, but no significant effect on pollinator density, though increasing from 1 to 2 cuts/year resulted in 3.5 times greater pollinator density.

This is good information for our own little meadow, because I wasn't sure if we should mow at all, but it sounds like it's a good idea; in our case, not only for the pollinators, but because in our area, completely stopping mowing is a good way to turn a meadow into a tangle of walnut saplings and nasty, fast-growing exotics like Tatarian honeysuckle and multiflora rose.

So it sounds like mowing once or twice -- maybe once in spring and once in fall -- might be the way to go.  That way the plants that die all the way back to the ground in the winter (like the goldenrod and bergamot) will get a fresh start each year, and we won't have competitors for the woody shrubs (such as the sumac, nannyberry, serviceberry, and elderberry).

I can't mow near where the buttonbush is, however, because the spring keeps that piece of the lawn soggy, and if I try to mow it our lawn mower sinks up to the axle and then I have to tow it out with my car.

Yes, that's the voice of experience, right there.

In any case, this paper was nicely timed from my perspective, as I was wondering what I'd do after the first frost when everything starts to die back.  Since we planted as we did to encourage the bees and butterflies, it's good to know that there's some solid scientific research to back up our choice of how to handle it.

With luck, in a couple of years we'll have something really beautiful to enjoy -- and a nice habitat for wildlife, as well.

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This week's Skeptophilia book of the week is for anyone fascinated with astronomy and the possibility of extraterrestrial life: The Sirens of Mars: Searching for Life on Another World, by Sarah Stewart Johnson.

Johnson is a planetary scientist at Georgetown University, and is also a hell of a writer.  In this book, she describes her personal path to becoming a respected scientist, and the broader search for life on Mars -- starting with simulations in the most hostile environments on Earth, such as the dry valleys of central Antarctica and the salt flats of Australia, and eventually leading to analysis of data from the Mars rovers, looking for any trace of living things past or present.

It's a beautifully-told story, and the whole endeavor is tremendously exciting.  If, like me, you look up at the night sky with awe, and wonder if there's anyone up there looking back your way, then Johnson's book should be on your reading list.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]