All life is surging with the first rains in the Top End
Early morning falls drought break of 20mm fills the reservoir lagoon
The cane toads are at it in broad daylight
45 killed in less than18 hours
Eggs in long spaghetti tubes
You can hall them in like its own fishing net
on the first morning after waters are all but clear of eggs
Some slip through defences in coming days
A price of not living here all the time
Now the water is thick with toadpols and it is hard to imagine that any other species has survived
Toadpols are a herding animal
They run from your shadow and can be corralled into
shallow corners to be scooped up in the thousands
It is carnage
The only bicatch is the water boatman who may well make it back to water - not a good sign for the few native frog spawn that was also present on the first day but it feels like a positive step.
I sing Dana Lyons’ ‘Cane Toad Muster’ as i wade through ankle deep waters net in hand.
The modified ecological context for this situation needs explaining
Sometime we call it the causeway
Sometimes we call it the dam wall
It goes into the natural sink hole that forms the wet season lagoon
Topsoil has been bulldozed on top of itself to be above the seasonal high water mark
Around it topsoil has been scraped away down to the coffee rock extending the period of standing water
within is a remnant lagoon that holds water longer than the rest of the natural lagoon
When rainfall exceeds 10mm the runoff from the woodland at Rakhi is captured within the remnant lagoon forming early pools frequented by numerous water birds
At the beginning and end of the wet season it holds a shallow body of water in the sun that is subject to daily heating and evaporation. A fairly common natural occurring situation where intermittent standing water is eventually inundated by a seasonal lagoon each year.
The excavation has effectively created a large swale that holds water both earlier and later in the rainy season providing extra soil moisture on the down side of it
It creates a situation for natural self sustaining rainforest once a canopy and leaf litter layer are established to reduce ground evaporation rates
Sometimes the early rains dry out and kill all early toads and tadpoles alike
With excess irrigation water pressure from the bore now being redirected into the remnant lagoon the waters have kept native fish through the season but will also keep the toad spawn alive
Chaos ever present when tinkering with ecology - I had not anticipated being overrun this year by the cane toad breeders
This year, my efforts aside, the early spawning has a good chance to make it to toads
There are a lot of them
When they get larger still and the water is higher they will swim together in a ball also making them easy to harvest, perhaps as fertiliser.
The behaviour makes sense for a poisonous mass spawning. Anything starts eating them they will be poisoned pretty quick.
Not my old pool net
I try to create enough space in the food Web for the other local species.
It is reported that the tadpol phase may last from three to twenty weeks
The rains fell on 18th October and by friday 2nd November - 15 days - there are toadlets in the 100s around the water’s edge while a mass of black toadpols still school together in the remnant waters.
In other years 10 toads in 24 hours would be a normal haul at the first rains
45 is a new record by a long way.
They were coming over the dam wall like cavalry over the battlements
Does it indicate a surge in toad numbers?
Last year was a big wet and all January and February the nights were full of toad song in the 20 hectare lagoon
That lagoon is yet to hold water as the dried soils soak up the early rains
The last thing we want is this modified ecological situation to benefit the toads at the native species expense
The grand chorus shared in a previous blog is yet to occur but i fear waters already full of toads will impact the productivity of this native frog breeding ground
The cane toad muster is faltering here at Rakhi and a new approach is required
My designers mind turns to modification of the Dam Wall to be a Toad Wall.
I think it could be a triumph of aesthetics and function but it is going to take time not available this season
This is certainly no endorsement of Trump policies although i am bemused by the ironic comparison. Shared humanity aside, I believe Mexican workers have had significantly better impacts on the US economy than Cane Toads on our ecology...
It may take a few years yet but It would be fitting to create a safe place for native amphibians, like this Roth's Tree Frog (rescued from the wall fan), to continue to breed and thrive here at Rakhi Retreat