Burn-off at Bujwa Bay

The only trouble with living in paradise (apart from the long commute) is combustibility.  Our gorgeous view – mile after mile of incendiary eucalypts.  So the still, dry days and nights of autumn were thick with smoke, not from the big bad one we’re dreading, but hazard reduction burns in the bush all round the town.

Last time I went down to Bujwa Bay, it was the kind of cool and breathless day that must make the Rural Fire Service very very happy.   Mist hovered over the water in a bright line of morning light.  Forty minutes of silent paddling past the sleeping celebrities of Berowra Waters and I was round Oaky Corner and into the sunshine.

In the quiet there was a cryptic crunching noise.   Eventually, I spotted the pair of glossy black-cockatoos hidden amongst at the shore-line casuarinas.  My sense of being some kind of bird whisperer evaporated when, after fifteen minutes fooling around trying to get a decent shot of the cockies, I looked up to meet the eye of a bloody great big white-bellied sea eagle sitting directly above me.  And then, just round the corner, his pal taking in the rays.  They’re not stupid these birds, parked in the sunniest spot on the bay.

Having bonded with the local bird-life, when I heard about the burn-off, I was worried.   What happens to it all when the bush goes up in smoke?

Bujwa bay wide view 2 best small

Egg the kayak entering Bujwa Bay after the burn-off

Drooping bark and grasstrees for crop square

Back-burnt grasstrees at Bujwa Bay

It’s not all bad news.

Harry Rechter describes  birds enjoying a feast during a controlled burn in Brisbane Waters National Park, not so far from here.
“Although fuel loads in the… heath and woodland were high, and flames soared above the tallest trees and shrubs, birds moved easily in front of and above the fire to appear minutes later on the blackened vegetation to feed on less fortunate insects and small lizards”.
I missed the raptors and the insectivores that no doubt turned up at Bujwa Bay at the first sign of smoke, looking for Cajun-style chow. But chances are these blackened grasstrees will be bursting into flower next time I paddle by.  I might see lyrebirds too, raking newly formed clearings.  Ground-feeders and grain-eaters – corellas for instance – return in force after fires have passed.  The little insectivores – thornbills, wrens and robins – that build nests close to the ground don’t miss the scorched canopy, and enjoy the bugs that flourish on the flush of new growth.  The carbonised shrubbery might even give me the chance of catching a blurry LBB or two on film.
Burnt crown and cliff

After the burn-off: partly scorched eucalypts

It’s a nice idea to think that the burn-offs that protect the town are a boon for the local plants and animals too.   And there’s a euphonious catchphrase that goes with that idea: “pyrodiversity begets biodiversity”. Fire incinerates the garden escapes and wakes the soilbank’s astounding store of dormant seeds. If we burn little and often, it’s been thought, we make a mosaic of habitats: patches of open space and newly germinating seeds; places burnt a few years back; and refuges long unburnt, full of craggy trees, hollow logs and dense undergrowth.

Pyrodiversity is popular amongst land management folks, and there’s some evidence that it works, at least in some places.  But not everyone buys the story that the frequent fires that protect people and property suit other critters too. Out in the mallee, near where I grew up, a fire and biodiversity project run by Deakin and LaTrobe universities has been laboriously checking the idea out.

For all the mallee’s underground lignotubers, ready to reshoot after fire, other parts of the ecosystem – large stretches of spinifex grass, for one, that shelter dragons and legless lizards – can take fifty or more years to return after a burn.  All of which makes me feel tremendously guilty about the swiftly abandoned spinifex-covered cubbies that my brother and sister and I used to make in the mallee scrub out the back of our house.  We will never know how many now-extinct species we displaced.

Away from regrets about the trail of ecological devastation I left in childhood and back to burn-off related angst. The research in these arid areas suggests it’s not pyrodiversity that’s important for a species-rich environment but having enough country that’s reached the right stage of maturity since the last fire.  As a person in mid-life, it pleases me to say that older vegetation often seems to sustain more species of birds, mammals and reptiles, including the rare ones. Even birds that like paddocks and open plains prefer unburnt land.  Some reptiles favour recently fired landscapes, but plant communities that haven’t been burnt for a decade or two harbor the richest variety of lizards and snakes.

I tried and failed to find the experts on biodiversity and fire on Hawkesbury sandstone.  But researchers studying both subtropical Queensland and foothill forests in Victoria said similar things.  A varied landscape is important, but

the richness of frugivore, insectivore and canopy forager assemblages is driven by the presence of structurally complex vegetation and old-growth canopy trees, which are more likely to be present in areas that have not experienced fire for a prolonged period of time (Burgess 2016)

Paston and colleagues put their conclusion bluntly: “prescribed fire is of little utility for the broadscale conservation of biodiversity” (2011, 3238).

And it seems, for birds at least, smaller patches of unburnt country won’t really do – it’s larger areas that haven’t seen fire for a while that are rich in species.  One bunch of researchers found that little islands of older habitat surrounded by new growth was grabbed by one or two aggressive predatory or colonial birds, rather than harbouring lots of different critters.  One recent paper, written about arid areas, sum it up:

Our results suggest a shift in current fire management thinking… is needed, away from a focus on creating small, unburnt patches towards preserving large, intact, unburnt areas (Berry 2015 493)

Burnt crown and dark silhouette from distance

What does all this mean for Bujwa Bay?

There was nothing moving in the incinerated trees on the ridgeline as I made my way up the creek at high tide, but then, it was early and damn chilly.  Even the herons had given up on fishing and were huddled in the trees, keeping their feet dry.

But the damp fringes of the mangroves were alive with silvereyes and yellow-faced honeyeaters, and I heard the plunk of a sacred kingfisher diving for breakfast.  Gullies are especially valuable habitats for birds at the best of times.  If they’re protected from fire by burning on the slopes nearby they can be an even better retreat when that big one comes.  The top of the creek was lush and green. I can only guess that the rangers and RFS know what they’re doing.

White faced heron in tree 2 square

Chilly looking white-faced heron

In the light of recent research, Taylor and his colleagues comment dryly “current fire management for avifaunal conservation may require substantial refinement” (Taylor, 2012, 525).

But let’s not fool ourselves.  Around here at least, fire management is not for the avifauna.  It’s for me, and people like me, who choose to live high on a hill, surrounded by the beautiful, burnable bush.

Additional references.  Because the whole thing is really is quite complicated and you might want to check I didn’t get it totally wrong.

Berry, L. Lindenmeyer, D, Driscoll, D. (2015) “Large unburnt areas, not small unburnt patches, are needed to conserve avian diversity in fire-prone landscapes” Journal ofApplied Ecology Vol 52 Issue 2

Burgess, Emma, and Maron, Martine (2016) “Does the response of bird assemblages to fire mosaic properties vary among spatial scales and foraging guilds?” Landscape Ecology March 2016, Volume 31, Issue 3,pp 687–699

Doty, A., Stawski, C, Nowack, J., Bondarenco, A. (2015) “Increased lyrebird presence in a post-fire landscape” Australian Journal of Zoology 63,9–11

Hope Ben (2012) “Short-term response of the long-nosed bandicoot, Perameles nasuta, and the southern brown bandicoot, Isoodon obesulus obesulus, to low-intensity prescribed fire in heathland vegetation” Wildlife Research 39(8) 731-744

Korczynskyj, Luke and Byron B. Lamont (2005) “Grasstree (Xanthorrhoea preissii) recovery after fire in two seasons and habitats” Australian Journal of Botany, 53 509-515

Kelly, Luke T. Andrew F. Bennett, Michael F. Clarke, and Michael A. McCarthy (2015) “Optimal fire histories for biodiversity conservationConservation Biology, Volume 29, No. 2, 473–485

Lindenmayer, David B., Wade Blanchard, Lachlan McBurney, David Blair, Sam C. Banks, Don A. Driscoll, Annabel L. Smith and A. M. Gill (2014) “Complex responses of birds to landscape-level fire extent, fire severity and environmental driversDiversity and Distributions 20, 467–477

Nimmo, D, Kelly, L., Spence-Bailey, L, Watson, S.J. Taylor, R.S., Clarke, M.F and Bennett, A.F. (2012) “Fire Mosaics and Reptile Conservation in a Fire-Prone Region” Conservation Biology 27 (12)

Pastro, Louise L., Christopher R. Dickman and Mike Letnic (2011) “Burning for biodiversity or burning biodiversity? Prescribed burn vs. wildfire impacts on plants, lizards and mammals”  Ecological Applications Vol. 21, No. 8, pp. 3

Robinson, Natasha, Leonard, Steven, Bennett, Andrew, Clarke, Michael (2016) “Are forest gullies refuges for birds when burnt? The value of topographical heterogeneity to avian diversity in a fire-prone landscape” Biological Conservation 200, pp.1-7

Sitters, Holly , Di Stefano, Julian, Christie, Fiona, Swan, Matthew, York, Alan (2016) “Bird functional diversity decreases with time since disturbance” Ecological Applications, 26(1), pp. 115–127

Smith, Annabel, C.Michael Bull, Don Driscoll (2013) “Successional specialization in a reptile community cautions against widespread planned burning and complete fire suppression”Journal of Applied Ecology 2013, 50, 1178–118

Alhambra on the Hawkesbury

The last few times I passed by Bujwa Bay, on my way downriver from Berowra Waters, it was shrouded in mist.

But last Sunday, in the golden light of late afternoon, there was a revelation.

I’m familiar with the Hawkesbury’s sculpture parks and sandstone art galleries.  But the fact that Berowra Creek had well preserved fragments of an ancient Moorish fortress – well, that was news to me.

When I went home and told RB I’d seen something very like the famous stucco inscriptions of the Alhambra on a estuarine cliffside at the end of Berowra Waters Road, his comment was “You’re barking!”.  And he’s probably right.

After all, the Alhambra is an artistic jewel, a masterwork of European Islam, preserved over the centuries after the Moors themselves were driven first into the mountains and then out of Spain altogether.  Its delicate carved plasterwork miraculously survived Christian conquerors, dodgy architectural restorers, squatters and tourists.  And the sandstone of Bujwa Bay is just, you know, rock.

But I’ve been reading about “thing power” and it’s given me a whole new angle on inanimate objects.  “Thing Power!” – sounds like a killer bathroom cleaner that will sort out all the disturbing life-forms, named and unnameable, in your shower cubicle.

But according to Jane Bennett, its “a creative not-quite-human force capable of producing the new [that] buzzes within the history of the term ‘nature’ ” (2010, 118).  Electrons, microbes, minerals, waste, all busily making and shaping things, inside, around, through, against and despite humans and their fancy-pants plans.  She reckons things and people rub along or against each other in a pattern that’s “not random or unstructured, but conforms to the strange logic of vortices, spirals and eddies” (2010, 118).

Kooky as it sounds, this is not a bad description of how the Bujwa Bay Alhambra came into the world, according to a paper coauthored, in a way that pleases my penchant for magical thinking, by a geologist from Granada, home of the famous palace.

Honeycomb weathering like this happens in all sorts of porous rocks, around the world – from Antarctica to Jordan – and maybe even on the surface of Mars. It might seem like  hollows would form in weaknesses in the rock, but it’s not necessarily so. Blistering heat, frost, chemical weathering and rain are all in the frame – with maybe a little help from the odd patch of algae or lichen. But mostly it’s about salt and wind.

Salty water – in this case from seaspray – seeps into the rock and crystallises, making tiny fractures. If there’s plenty of water, salt crystals forms on the outside surface to form efflorescence, a mineral flowers blooming on a cliffside or a cellar wall or a garden fence.  But the real damage is done deep in the rock.

According to Rodriguez and friends, once a depression is formed in the rockface, wind eddies and swirls inside the concave parts of the stone.  Faster breezes mean more evaporation and a super-saturated salt solution, meaning more salt crystals and more fretted stone. Eventually the rockface becomes lacework, without any intervention by a rock lacemaker.

Alhambra rocks 1 crop long

The other name for honeycombed rock is alveoli.  It’s stone with lungs.  Made of mineral flowers.  Not alive (or mostly not alive – sorry algae) but doing complicated and beautiful things.

Not immortal, invisible, unfathomable.  In fact, as fathomable as the waters of Bujwa Bay at low tide, that is, knee deep to a heron.  Just exceedingly hard to grasp.

And that’s not just me banging my head against a corroding brick wall of “Salt weathering: a selective review” – the geologists are still bickering over exactly how it works. In Bennett’s (possibly slightly loopy) words, it’s vital matter, “hard to discern… and, once discerned, hard to keep focused on.  It is too close and too fugitive, as much wind as thing” (119).  Or perhaps, in this instance, both wind and thing.

tiny crab and shadow.jpg

A crab wondering what I’m on about, on a beach near Bujwa Bay

References

Jane Bennett 2010 Vibrant Matter, Duke University Press

Eric Doehne (2002) “Salt Weathering: a selective review” from Natural Stone, Weathering Phenomena, Conservation Strategies and Case Studies. Vol 205, 51-64, Geological Society Special Publication

Carlos Rodriguez-Navarro, Eric Doehne,Eduardo Sebastian (1999) Origins of honeycomb weathering: The role of salts and wind, GSA Bulletin; August 1999; v. 111, no. 8; p. 1250–1255

Huinink, H. Pel, L, Kopinga, K. 2004 “Simulating the growth of tafoni” Earth Surface Processes and Landforms 29 1225-33

Of gods and map readers

I’m running out of map!

It’s not a real cartographic apocalypse – a Ken Loach-influenced Dr Who episode in which all the world’s maps are stolen away by some evil alien civilisation heavily invested in NavMan shares. But after a year with my canoe, there’s not much unexplored territory on this part of the Hawkesbury.  I’ve nearly done with the alchemy of my Saturdays: transmuting ink on paper into trees and water and mist.

Maybe it’s my fading memories, but as I paddled just after dawn from Deerubbin to Kimmerikong Creek, I kept thinking of the west coast of Scotland.  Something about morning fog: the sea eagles appearing and vanishing; mist spilling over the ridgelines and pouring down the slopes like an evanescent avalanche.

I remember my first view of Glen Coe through the bus window, RB naming each hill as we passed.  What a gift, I thought, to know a place like this so very well.

I was at a disadvantage this Saturday: I forgot my map, carefully folded into its extra large, double-sealed “Hercules” zip lock bag and left on the kitchen table. Google Earth is one of those things that prove we really do live in the future.  And RB is always complaining about how rubbish Australian mapmakers are compared to the unsurpassable Ordinance Survey.  Even so, I still think maps make us into gods.

With a map you know what’s going to happen next: what’s beyond the next hill or around the next corner.  Geological maps and navigational charts are even better – you see into the depths of ocean or stare right through the surface of the earth.  Short of being an X Man with laser eyes or clairvoyant powers, it just doesn’t get any better than that.

If you’re going to claim someone’s country or rewrite its history, of course, a map is a magnificent weapon.

Of course, the untraversed parts of the map are the tricky ones, a little bit too far away from a put-in, further than the old easy jaunts.  So it’s through known country to the unknown: past the Whirlpool of Death and Bar Island’s grumpy whistling kite, beyond the verdant urine-fertilised fields of warrigal greens at Back Beaches, though not quite as far as Ant Hill Point (saving that excitement for a really slow weekend).  Just when you feel you are truly in the wilderness, with only cormorants for company, you turn a corner and there’s a line of houses that look like they’ve been helicoptered in from deepest suburbia.  I half expected to hear a solar powered leaf blower or hedge trimmer.

Just across the other side of Berowra Creek, Muogamarra Nature Reserve is deliberately kept something of a secret.  It’s only open to the public six weekends of the year, in early spring.  There is a field station there, and in the water of Kimmerikong Bay scientists have been testing those Qx resistant oysters I regaled you about a couple of months back.  The reserve was originally declared in the 1930s to protect the many rock carvings, hand stencils, scarred trees, middens and grinding grooves there: this is a landscape long and intimately known.  However, I guess National Parks are trying to stop this particularly lovely part of Hawkesbury sandstone with its 14 mammal species (including tiger quolls!), 900 plant species and 140 varieties of birds from being “known” in a biblical sense; that is, not to put too fine a point on it, screwed.

I hear that Cowan, the town that sits on the edge of Muogamarra, had a crime-wave a while ago.  Since no-one locks their cars, a street’s worth of gps’s disappeared in a single night.  A sign was put up in the window the general store: if all the missing devices turned up outside the community hall there’d be no need to call the police.  Everyone got their Tom Toms back.  This story gives you a hint of how the people of Cowan might view the official regulations preserving the sanctity of Muogamarra.  Since I was an incomer from Berowra, a good six kilometres away, however, I figured I was safer keeping my feet in my canoe as I wound my way through down Kimmerikong Creek, deep into the reserve.

The creek, looping from the cliffside on one side of the valley to the escarpment on the other, looks nothing like it does on the map, but exactly as it does from space, the shroud of mysterious grey mangroves slowly falling back as you paddle upriver, exposing the glint of the creek to a satellite’s view.

Google Earth may have imaged the mangroves of Kimmerikong Creek to its satisfaction but I know I haven’t captured it to mine.  Somehow my wan photographs of these flooded forests fail to catch the sense of invisible ferment, mysteries hidden between the hoary tree trunks and their reflection, the hush that hints at unknown things slowly emerging.  I imagine a wading Ent, striding and squelching towards me through the mire, hairy-legged with pneumatophores and flanked by an bevy of miniscule leaping fish, wearing a National Parks and Wildlife uniform and demanding payment of that $3,000 dollar fine.

No Ents this time, though, and no bird photos either.  I heard, I think, maybe 138 species of bird as I ducked and crashed through the overhanging branches, and didn’t see even one.  Perhaps I need to get up even earlier – 4 am? 3 am? – to capture the mangrove’s magic, as The Goat the Wrote does in his stunningly beautiful photos.  The stalwarts of the Hawkesbury Canoe Classic can paddle all night, so why can’t I?  111 kilometres in a one day – with that kind of stamina the folds of the map would open up like a flower.  Ant Hill Point here I come!

I’ll have to work on it.  This time there was no bonk, but the pied cormorants of Milson’s Passage looked on pityingly as I swirled downriver through the tidal race, kermit-armed, back home to my plans and my maps.

Two sad islands, three whistling kites

It’s 7 o’clock on a midwinter Sunday morning.  It’s five degrees C.  And I’m about to go canoeing.

The thought that I may be slightly mad has passed through my mind.  A key motivation for hauling myself out of bed before sunrise was to try to get a better look at the whistling kite that hurtled past me into the distance last time I put the kayak in at Mooney Mooney.  And as I’m standing in my innovative Milan-style long-johns and wetsuit combination, what do I spy, perched in a dead tree right above the car park, but a whistling kite, defrosting in the first light.  Tempting get that pic and hightail it back to bed.

But no, Bar Island is calling me.  I’m heading back to the spot where I first decided, on a boatie camping trip just up the river at Back Beaches, that my mental health demanded the purchase of a cheap canoe.  And halfway across the river, when the first rays of the morning sun hit me, I feel truly blessed.

Bearing in mind my favourite quote from Antonio Gramsci (“pessimism of the intellect, optimism of the will”), I started out my jaunt by heading across to Olga Bay. Last time I was there, a magnificent white bellied sea eagle swooped through the golden afternoon sunshine and snatched a fish from the briny right in front of the boat.

Unfortunately, convinced that the Hawkesbury was going to sweep me out to sea, at the time I had my head down, as I blasted my way across the river.  The David Attenborough moment passed while I was fumbling around in the dank reaches of the canoe for my much abused camera.

Needless to say, the sea eagle didn’t do a repeat performance, though that Australian darter that I pursued heartlessly from perch to desperate perch up the Wyong River last weekend had an unpleasant surprise on that therapeutic holiday to a little hire cottage on Milson’s Passage that the doctor ordered.

Bar Island greeted me with the green flash of (what I think was) a sacred kingfisher watching from the mangroves as I clambered awkwardly (camera-less, of course) over the slippery rocks to the shore.

To be honest, I found it a gloomy place, weighed down by history and hemmed in by trees.  They’re important trees – casuarina glauca for the glossy black cockatoos and red ash which, according to the informative signs, feeds the copper jewel butterfly.  Perhaps I’ve been living with a Scotsman too long.  I have started to share his culture’s love of denuded landscapes and the sweeping views created by sheep, deer and industrialisation. We’ve dubbed the accompanying fear of excessive greenery “wood psychosis”.  There was a bit of wood psychosis going on in Bar Island this weekend.

And then there’s visible colonial history of the place.  St John’s Church was built on Bar Island in the 1870s, and the grave stones of some of the sixty or so European settlers who are known to have been buried there remain, along with reminders of the troubled history of the Hawkesbury as a brutal contact zone.  “A difficult time” as the plaque commemorated Sarah “Granny” Lewis carefully puts it.

The best spot to be on Bar Island on a chilly winter morning was, not coincidentally, the wooden seat near the midden on the northern tip of the island.  The midden’s metres deep, accrued over thousands of years of shared oyster eating by Darug, Darkinjung and Guringai people, whose country meets here.

And not far away, the resident kite and her nest, were also basking in sunlight.  RB has been working here, on and off, for three years, and the nest has been there for at least that long, renovated and extended each season.  The kite wasn’t moving, despite the clumsy paddling and clicking camera.  It’s her island now, and she knows it.

I thought I was smart, timing my trip upstream with a rising tide.  I wasn’t feeling quite so clever heading downriver again as I tried to take a racing line across an sharp S bend, with the current and the tide battling it out all round me.

First I ploughed exceedingly slowly, on that perfectly still day, through a stretch of strange standing waves.  And then I found myself swirling through a sequence of weird vortices, that churned up silt and the occasional jelly blubber.  I read Lisa-ann Gershwin’s Stung! On Jellyfish Blooms and the Future of the Oceans a while ago.  She concludes, to put it bluntly, that we should enjoy fish while they last, as the jellyfish, floating around in the oceans since the pre-Cambrian, are on their way back with a vengeance, thanks to acidified, over-fertilised and over-fished oceans (not to mention climate change).

Since then I see every jellyfish as a portent of doom.  Given this slightly apocalyptic worldview, after about an hour and a half trying to escape this turbid hellhole (okay, it was about ten minutes) I began to worry that one of those whirlpools were going to suck me down into the bowels of the river, just the icefloes in this extremely spooky youtube find.

Needless to say, I survived The Whirlpool of Death.  In marked contrast to many of the people who went to live at Peat Island, which I paddled past on the last leg of my route home. Built to detox alcoholics early in the twentieth century, the site was used for over ninety years mainly as an asylum for people with mental illnesses or learning difficulties.  From all reports it was a horrifying place where inmates were caged, neglected and sexually abused.

The last residents, treated somewhat less brutally than those who came before, left in 2010, and the site is now padlocked and empty, awaiting redevelopment into a 250 berth marina and suite of five storey apartment blocks.  Because there’s nothing that says “high density living” and “brownfield site” like a place with national parks on all four sides.

I spotted one last whistling kite – in fact, a whistling kite actually whistling – in the Norfolk Pines on the island.   And in the distance, somewhere out of view, the elusive sea eagles, honking away like a pair of castrati ducks.  I know it’s sentimental in the light of these grim tales of the river, but I hope the birds are still there when the jet skiiers come to stay.

Sprinter (not yet Sprummer)

Tim Entwhistle from the Royal Botanical Gardens suggests we add two seasons to the European standards: starting out with the clunkingly named Sprinter, to describe late winter and early spring when most things seem to burst into flower.  He reckons non-Indigenous Australians can’t handle the complexity of the diverse seasons observed by Kooris, Murris, Nunga, Noongar and all the first people of this place.

He’s probably right.  The D’harawal calendar – from people south of Port Jackson – says roundabout now is the time of Wiritjiribin – cold and windy. I think I saw Acacia floribunda blooming today, so that fits.  But maybe, since its getting warmer, it’s closer to the time of Ngoonungi, the time of the gathering of the flying foxes?  “They come in from the north-east, the north, the north-west and the west, and swirl over the Sydney area in a wonderful, sky-dancing display just after sunset”, says the D’harawal calendar on the BOM.  No signs here at least, in Dharug and Guringai country, of flying foxes yet.

Let’s face it: I’m clueless.  I’ve got no idea about the local wildlife, know nothing of how you might live off the land, can’t even figure out half the Latin names of the flowers in our neck of the woods – MuogamarraBerowra National Park, Lane Cove.

Ok, I’m cheating. Lane Cove is miles away, but I took some nice pictures there yesterday.  And it is (mostly) on Hawkesbury sandstone.  And they have a great website for the local flora.  Which is important because this is what our plant identification book looks like:

Destroyed Robbo rotated

All in all, I think I’m only up to Sprinter.