Wolves and Livestock Depredations

[mdunc8]

Here's a new study on the efficacy of using lethal measures on wolves thought to be involved with livestock depredation. Thoughts?

 

[shoots-straight]

Well it might increase livestock depredation but surely will decrease the amount of wildlife killed. So increasing the kill of predators has some great side benefits. Just kidding Eric, Shooter etc.

They claim that a 25% harvest of wolves is unsustainable, but from what I've heard from experts that will only keep the predators at bay. =

 

[RobG]

The sustainability argument doesn't make sense. I don't think you need to decrease them by 25% every year for improvement - just maintain them at a level at least 25% less than your baseline. For example, if you originally have 100 wolves the study suggests that
1) you will make things worse if you maintain a population of 90 wolves;
2) you will break even if you maintain 75 wolves;
3) you will improve the situation if you maintain 50 wolves (but your losses won't be reduced by 1/2).

 

[Pinecricker]

I hate getting into these kinds of discussions because they tend to lead nowhere, BUT the flaw in the analysis is that there really isn't very good data on the true wolf population or how quickly it is expanding <wolf lovers flame away>.

The "documented breeding pairs" data is sketchy at best. Wolf biologists (the ones actually working for Fish and Game departments responsible for trying to count wolves - not those from NGO's) are the first to admit this. States have scant resources to cover an impossible amount of terrain. Counting every last wolf, or even developing an accurate estimate, is and exercise in futility. This is why they are always careful to quote their counts as minimum numbers, and to caveat them as very rough estimates based on sampling.

If the total numbers, or rate of expansion were even moderately higher than the numbers cited in this study, then a completely different conclusion could be drawn. That being said, it is a very interesting hypothesis. Better data is needed to draw any meaningful conclusions one way other the other.

 

[RobG]

A layman's interpretation of the study is here. The pack breaks up if the leaders are shot and more breeding pairs are created.

This thread last month was based on the same study: http://onyourownadventures.com/hunttalk/showthread.php?t=261581

 

[Deleted member 16014]

I agree with Pinecricker on this for the most part.

I've combed that paper pretty carefully and have a few beneficial take-away's, as well as a few issues.
--A curvalinear relationship for predator/prey interactions is not uncommon.
--The 25% lambda (intrinsic growth rate) is a very fluid number, but the fact that the break of the curve (wolves killed vs. cattle depredation) is at roughly 25% adds some weight to the results
--I don't feel that a correlative, west-wide, assessment has much real world applicability when PVA's (population viability assessments) and depredation issues occur at a state/forest level.
--In reference to the correlations, some of the r-squared values are pretty low (.15-.30) despite being statistically significant.
--Having gone through the supporting literature the authors cite, the assumption that breeding pairs do the majority of killing may or may not be true. It's probably very seasonal and locally biased. Biased in the statistical, not opinionated, sense.

Creel and Rotella (2010--Meta-analysis...) came to the conclusion that human removal of wolves has a far greater influence on population viability than originally thought. The apparent contradiction between their conclusions and those of the paper in question is likely a matter of scale in my view. That Creel/Rotella paper made a lot of waves when it came out as I recall.

I think the paper in the OP brings up some good points and it's rational to consider whether predator management techniques are achieving what we think they are. This is often skipped by all sides of the argument.

 

[Deleted member 16014]

Thanks for posting that Rob.

The Brainerd studies talk a lot about the effects of removal on wolf social structure. If I recall it's a pretty complex deal.

 

[TheJason]

One question that I think needs answered is, did livestock management practices stay the same? Did they try any preventative measures? Did time of year influence the depredations?

Correlation does not equate to causation.

 

[Pinecricker]

One question that I think needs answered is, did livestock management practices stay the same? Did they try any preventative measures? Did time of year influence the depredations?

Correlation does not equate to causation.

Great questions JLS. I think that instead of looking at the total numbers for the three states, they need to do a sort of case study for a smaller geographic area with a few packs, where they can actually isolate cause and effect.

Perhaps the take away from the study is that for controlling damage to livestock, you really need to kill the entire problem pack, not just one or two individual wolves.

 

[1_pointer]

I agree with Pinecricker on this for the most part.

I've combed that paper pretty carefully and have a few beneficial take-away's, as well as a few issues.
--A curvalinear relationship for predator/prey interactions is not uncommon.
--The 25% lambda (intrinsic growth rate) is a very fluid number, but the fact that the break of the curve (wolves killed vs. cattle depredation) is at roughly 25% adds some weight to the results
--I don't feel that a correlative, west-wide, assessment has much real world applicability when PVA's (population viability assessments) and depredation issues occur at a state/forest level.
--In reference to the correlations, some of the r-squared values are pretty low (.15-.30) despite being statistically significant.
--Having gone through the supporting literature the authors cite, the assumption that breeding pairs do the majority of killing may or may not be true. It's probably very seasonal and locally biased. Biased in the statistical, not opinionated, sense.

Creel and Rotella (2010--Meta-analysis...) came to the conclusion that human removal of wolves has a far greater influence on population viability than originally thought. The apparent contradiction between their conclusions and those of the paper in question is likely a matter of scale in my view. That Creel/Rotella paper made a lot of waves when it came out as I recall.

I think the paper in the OP brings up some good points and it's rational to consider whether predator management techniques are achieving what we think they are. This is often skipped by all sides of the argument.

Nerd level analysis! Quite refreshing, thanks!

As an aside, I tried to get a graduate degree with Creel as I knew one of his advisers at Purdue. No funding and thus I went elsewhere and to a different field...

 

[RobG]

Thanks for posting that Rob.

The Brainerd studies talk a lot about the effects of removal on wolf social structure. If I recall it's a pretty complex deal.

What do you think of the statement that 25% reduction is unsustainable? (Page 12 - because it will lead to relisting). It seems nonsensical - you don't need to reduce the population by at least 25% each year, you need to use management to keep levels at least 25% below unmanaged levels. Surely the wolf advocates will latch onto this "science."

The main conclusion about increased breeding pairs seem plausible, but I read that particular conclusion about unsustainability and it makes me question the author's motives. Missing also is a suggestion that removing entire packs as a viable option, which is consistent with their findings.

These seem to be fairly obvious oversights that should have been caught by the reviewers. Is this a respected peer reviewed journal?

 

[Deleted member 16014]

I agree that the statement you are referring to is a reach. I think that because their curve broke around 25% and some other people figured that lambda might be around 25%, they thought they were really on to something.

General Linear Models and regression analyses are great for teasing out relationships in observational data. Their weakness is that they don't tell you much about the why/how, and may or may not mean anything on the ground. Ideally, as Pinecricker noted, you'd take the relationships that were seen here and test them on a smaller scale so you can eliminate a lot of the noisy variables that aren't useful.

I'd personally put PlosOne in the second tier of primary literature. Probably not a Science, Journal of Ecology, or REM level, but professionally peer reviewed nonetheless. I could be wrong, these are circles I dabble in, not run in.

JLS, I can just about guarantee that management was different all over the study area and between years. Even if livestock operators didn't hire additional cowboys, adjust pasture use, etc. (which they probably did), they definitely spent a lot more time looking for dead animals. They typically only get paid by state game damage boards for losses if wildlife officials verify that it was a depredation. Therefore it's in their best financial interest to invest the time to find kills before they can't be verified---this leads to less time w/ the livestock, which is usually bad for both the resource and the animals.

Pointer, in my experience Dr. Creel is very intelligent, errs on the side of preservationism, and comes across as arrogant. There are others in the MSU ecology/biology stable that are much easier to get along with, but the guy has published some big time stuff and I respect him as a scientist. He is also a heck of a mountain runner and ice climber.

 

[TheJason]

Perhaps the take away from the study is that for controlling damage to livestock, you really need to kill the entire problem pack, not just one or two individual wolves.

I think that is a very accurate statement.

I am very interested in the research results for non-lethal measures, as I think that should be the focus for long term deterrence of depredations. However, for dealing with the right here and right now, I think removal of the entire pack or majority of the pack might very well be the most effective option.

 

[mtlion]

Pointer, in my experience Dr. Creel is very intelligent, errs on the side of preservationism, and comes across as arrogant. There are others in the MSU ecology/biology stable that are much easier to get along with, but the guy has published some big time stuff and I respect him as a scientist. He is also a heck of a mountain runner and ice climber.

Friends of mine were terrified of Creel as undergrads. He had a way of looking through you and we always joked he was scanning our brains to judge us. It doesn't surprise me that he comes off as arrogant but I will say this he is quite likely one of the smartest men I've met and it must be quite difficult to deal with "normys" when you see the world like he does.

As a side note Rotella was my advisor as an undergrad and I took a grad-level population bio course from him, one of the nicest guys you will meet. Super good guy.

 

[katqanna]

I think that is a very accurate statement.

I am very interested in the research results for non-lethal measures, as I think that should be the focus for long term deterrence of depredations. However, for dealing with the right here and right now, I think removal of the entire pack or majority of the pack might very well be the most effective option.

JLS, I set up a presentation fall 2013 that sought proactive preventative measures between large carnivores and livestock. I invited several members of APHIS to do presentations on a new program they are trying here in MT focusing on preventative methods; we had Abby Nelson, FWP's wolf biologist ; George Edwards with the livestock loss program with the grants for preventative methods. I also brought in Peggy Dezabou, a sheep rancher northwest of Helena and a breeder of Akbash guardian dogs (she brought 2 with her); Becky Weed, a sheep rancher just north of Bozeman that uses pyrenees; Matt Barnes a range rider that works with Keystone Conservation with cattle ranchers (they also use Kuvash breeds of dogs); Hilary Zaranek a range rider and cattle rancher.

Hilary ranches and runs a range riding cooperative in the Centennial Mountains area. When they began applying range riding and other preventative methods their depradations dropped to 0 and have been that way for the few years they have been doing this. They have wolves and bears to contend with regularly. One of the things she spoke about was training the cattle to act more like bison, a wild quality that was bred out of the domestic cattle in favor of passivity.

While these methods often take trial and error to find the right timing of application or combinations that work best for the geography, weather, etc. for the individual rancher, they can assist, especially since genetics cannot necessary be comped with the loss payments.

Recently APHIS has taken the layout and participants of my presentation and put them on in a few cities, the most recent Dillon. My hope is to remove some of the social/political conflict between wildlife and ag, partly because I have interests in both. But looking through numerous academic papers on predator subjects, which I know is contentious in itself, you are not going to please everyone, no matter what "science" is produced and posits.

 

[Dakota79]

Just curious but how do you train cattle to act more like bison?

 

[katqanna]

Dakota79, bison graze the land more on the move, rather than camping for awhile in an area. So one thing the range riders do is to keeping them moving, more like wild bison, making them less of a target and they are more bunched during the grazing. Another thing Hilary pointed out was that when threatened, bison bunch up, weaker ones like calves in the center, so they train them to bunch when threatened for defense.

Just tried to find the video I took of the meeting for her other points, but that was pre new harddrive and OS install last winter, so who knows what folder I shoved that in before I migrated files. But I did find an interview she did with NPR where she stated,

ZARANEK: And, of course, cattle are the domestic version of bison. And so there's no reason cattle can't function similar to bison.

ROTT: She believes all they need is a little training. So Hilary comes out every day, twice a day at dawn and dusk, and takes her cows to school. She's a mother of three, so it's a bit taxing. But she says, so far, it's been worth it.

So the ones that you had kind of trained to group up like that, like a herd...

ZARANEK: We had no depredations. And there was a den in that pasture.

ROTT: A wolf den?

ZARANEK: Mm-hmm.

ROTT: Oh, that's pretty good evidence that it, that is it...

ZARANEK: It's a start.

She was in a short film which showed some of that, I believe it was at the Emerson here in Bozeman but with the concussed brain, I cant remember which group produced the film to even find it right now. It will probably come to me when I try to fall asleep.