Tuesday, February 7, 2017

Feral Cats And The Trickle Down Effect

If Tasmanians were really serious about sustainable environmental management the might consider tackling the 'feral cat' problem. With trees dying at various times and in various bio-regions it is very clear that something is out of kilter in the natural environment. And most of all the 'problem' will ultimately come back in large measure to humanity's impact upon the current and evolving ecosystem.

Given that the 'blame game' has to begin somewhere and typically as far away from 'human impacts' as possible, one can pick almost any point in the spectrum to start  doing some research.  The fashionable thing to do these days is to call out 'climate change'. Usefully it comes with a convenient amount of 'political cargo' that all too often can be claimed to originate 'somewhere else' and/or with 'someone else'.

Speculatively, let's throw the feral cat issue into the ring in regard to the current tree decline events being experienced in Tasmania. It's unlikely to be the whole problem but its equally unlikely that feral cats are playing no part at all.

There has been speculation that insect predation on 'White Gums (E. viminalus)' and feasibly that could be a factor. Indeed it was in the Tasmanian Midlands but there possums were also predating the trees and the trees were under drought stress. However, after a somewhat wet winter it's feasible to exclude insects and drought working together. Nonetheless. the consequent flourishes of new growth plus a relatively warm summer might turn out to be good for the insects but in ecosystems there is always something waiting opportunistically in the wings. Here that might well be 'the birds'  and it has been noted by some that the numbers are down.
So which birds are missing? How many compared to some known number in the past? What factors are impacting upon what populations? What are the knock-on effects of any perceived change? What landscapes are the birds being lost from? And there will be even more questions arising from these.

If feral cats are thrown into the equation, what do we know, that's actually know, about their population level? Is there a correlation between 'cat numbers' and 'bird numbers'?  If so why so? If so what action to be taken if any?

Indeed, who is asking such questions and in  what context? It is speculated upon, based upon anecdotal evidence, that feral cats are having an enormously negative impact upon 'cultural landscapes'. Just what are the impacts and on what evidence?

The research task here is non-trivial and 'citizen scientists'  with a modicum of literacy and numeracy might well play a role IF they weren't sidelined by 'the professionals'. The Southern Indian State of Kerela is an exemplar where 'citizen science' was employed for such a purpose. In fact Kerela can lay claim to being the home of LANDliteracy and mainly so because of the region's very high literacy levels that has facilitated the region's high levels of 'social activism'.

All that aside it is well known that if there is a lot of something in a cultural landscape it is possible to remove it, often extinguish it, via the mechanism of 'unsustainable harvesting/exploitation'. It's a tried and proven methodology and should feral cats be implicated in 'TREE DECINE' harvesting them for a profit is a potential way forward.
 
Forget any notion of a subsidised eradication program and especially so in Tasmania. It was tried with foxes in Tasmania and not a fox was found until the program looked like it might be abandoned. More to the point there was a parallel refusal to address the feral cat issue as, according to some, "that'd kick-in when the fox thing is over". That's possibly a bit cynical but there may be some truth in it?

REFERENCES: 

Literacy Campaign, Land Literacy and Watershed Development
Subrata Sinha and Arun Ghosh Economic and Political Weekly

Vol. 32, No. 6 (Feb. 8-14, 1997), pp. 280-288 ... https://www.jstor.org/stable/4405071?seq=1#page_scan_tab_contents