Red deer threat !

I really disagree with this, and the very flimsy 'science' it's based on.

There is no good evidence that sika will outcompete red on a national level. Absolutely none, despite a lot of people putting in a lot of effort to find some.

They may do so in some very specific local contexts - such as dense commercial conifer plantations. But even there, the more likely explanations for sika being more abundant in those areas are simply that (a) reds are much easier to detect and shoot, and (b) reds were absent or at extremely low density when sika arrived in these areas. There is NO good evidence of sika displacing red from anywhere where red were abundant when sika arrived.

There is also no evidence of ongoing hybridisation with reds. 15 years ago, the fear was that the whole GB Cervus population would turn into a hybrid ‘swarm’. This hasn’t happened. There is no genetic evidence for recent hydridisation events: all the detectable introgression is now several generations old. Yes, there are areas with hybrids, but these are descendants of cross matings that happened in the 90s and early 2000s. There are large areas where both species occur, and no new hybridisation.

This article is based on some extremely shoddy work published last month that trotted out tired old claims about sika being some kind of Uber deer, based on data that I'd have failed an Hons student for. The fact is that sika have been out there for over 100 years, and during that time BOTH red and sika numbers and range have expanded. The comparison with red and grey squirrels falls completely flat.

Sika are a commercial pest if you're a forester. They may cause you some problems if you're attempting to regrow native woodland (though we don't yet have much data on this). They don't seem to much like arable land. They largely avoid the open hill and rough grazing.

Any landowner with a well implemented deer management plan informed by clear objectives and decent population data will effectively manage sika just as well as any other deer. There really is no need to be alarmist about them.

(All of this I told the Non Native Species Secretariat in the Invasive Species Risk Assessment I wrote for them last year. They were very unhappy about it, and I suspect the recent uptick in anti-sika material appearing in various places is because someone on the panel leaked the draft report).
 
But you'd agree that red deer have been unfairly hammered at least ?
That's a lot less clear - the answer is very context dependent. It is also a completely separate issue to sika. It helps no one to conflate sika deer (mis)management with red deer deer population declines.

The overall picture for GB as a whole is an increase in both red deer total population and range. This is especially true in England and in lowland areas of Scotland, where there have been pronounced range expansions into areas that hadn't held red deer for hundreds of years (and have very little history of red deer management).

The picture for Scotland is very messy, made worse by the lack of a consistent nationwide survey. The best available guesstimates suggest little change in the total number of reds, or possible a slight decline from a high in the early 2000s - but with so much error in the estimates that you can't really have any confidence in any apparent trends. What seems clear, however, is very high local variance. Some areas have seen dramatic declines as a result of savage culling, both by FLS and by private estates starting to undertake large scale tree planting. However, other areas have seen dramatic increases, or reds appearing for the first time.

There is absolutely zero risk of reds going extinct, either because of overshooting or being outcompeted by sika. They may well be shot to to lower densities than we're used to, and that will mean a bit of getting used to. But anyone who claims they're going to be extirpated either doesn't know what they're talking about, or is being deliberately dramatic.
 
Well, it's good to have that overall picture. From the layman's eyes, it just seemed red deer had been reduced to vermin status for political ends.
 
Is it understood why sika crossbred with red deer but don't do it now, and you'd presume won't do it in future? It seems an odd situation.

There is also no evidence of ongoing hybridisation with reds. 15 years ago, the fear was that the whole GB Cervus population would turn into a hybrid ‘swarm’. This hasn’t happened. There is no genetic evidence for recent hydridisation events: all the detectable introgression is now several generations old. Yes, there are areas with hybrids, but these are descendants of cross matings that happened in the 90s and early 2000s. There are large areas where both species occur, and no new hybridisation.
 
Well, it's good to have that overall picture. From the layman's eyes, it just seemed red deer had been reduced to vermin status for political ends.
Oh they have.

But that doesn't mean that they're going to be driven to extinction. Even the most rabid tree planting green zealots acknowledge that SOME deer are desirable.

Even if the Scottish government decided to try to actively eradicate them, they'd fail.

Red deer numbers will probably come down across a lot of the traditional open hill range, probably to about a tenth of what they were at their peak, at least in the short term. However, keeping them there will require that someone pay the ongoing costs of hind control. Once the subsidy money or green investment direct grants run out, it's not clear who this will be. So my prediction will be that the very low population density will only last a decade or so at most in many areas, and then it will start creeping back up. By then, they'll be in areas that are now covered in woodland - which is (as everyone knows) much, much harder to control deer in. So give it 50 years, and there will probably be just as many again - just now in the middle of forests.

There are people who think this is where sika will have the edge, and they will invade new woodland faster and outcompete reds, excluding them in the long term. The available evidence from New Zealand suggests not, and indicates that they do undergo some niche separation, allowing co existence.
 
If you think about it, given ScotGov's track record, the very best thing they could do to ensure the continued persistence of red deer is decide to eradicate them...😁
 
Is it understood why sika crossbred with red deer but don't do it now, and you'd presume won't do it in future? It seems an odd situation.
It looks like it tends to only happen in very restricted populations, where there is limited choice and limited or no option for dispersal,

Most commonly when red stags got into fenced enclosures with sika hinds. The height difference means it's mechanically very difficult for sika stags to mount red hinds.

Almost all the original crosses can be traced back to deer parks or enclosures.

Where they have free choice and freedom of movement, the genetics suggests that they don't cross breed very often at all.
 
Look at Crows/Hooded Crows they have adapted to keep the 2x populations apart with an area of overlap.

Red deer, will have some gene flow, from Sika, long term which genes will dominate will be heavily influenced by how the habitat develops and thus favours one species at the expense of the other.
 
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