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Apr. 2nd, 2006 @ 09:57 am (no subject)
(Hrm - long time, no posts... I was talking with someone about this community the other day, and they thought it was an interesting idea, if only as a forum to force yourself to read one paper per...oh, month, week, whatever personal deadline you have set for yourself, and then post a normal-person-readable assessment of it - an idea that perhaps some of y'all might be interested in, if only as a way to force you to confront the ever growing Stack that I know is sitting on your desk)


So, I was recently fascinated by Essington et al's Fishing Through Marine Food webs. As a conservation minded food web ecologist, I open nearly every grant proposal with something like "In marine systems, we are removing species at the top of the food web first (Pauly 1998)." Which comes from Paul's Fishing down the food web paper. Now, the data from that is actually publically available, and I recently decided to jump in to look at patterns of biomass change by trophic level in California. And you know what, I didn't see the "fishing down the food web" thing at all. Rather, change in mean trophic level was driven soley by anchovy, sardine, and oyster harvest. Weird, I thought to myself.

And then comes Essington's piece, showing that "Fishing down the food web", the phenomena of fishing at lower and lower trophic levels at species at the top of the food chain are depleted, at least in catch data, is only true for the Gulf of Maine. Everywhere else, it's driven by ADDITIONS of lower trophic levels, while biomass at upper trophic levels stays relatively constant.


Of course, there's all of the work by Ram Myers and the like that shows that, when looking at assessment data, not catch data, we're still taking out the top of the food web first, but, this whole thing has made me look at fisheries catch data and data from harvesting (e.g. logging, hunting, etc) with a far more critical eye. How useful is this data, and what care needs to be taken with it? Quel interesant.
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furry lobster arms
Jan. 22nd, 2006 @ 04:38 am Introduction, as required
Current Mood: curiouscurious
I just joined this community, and as requested...

an introductionCollapse )
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ice crystals
Jan. 16th, 2006 @ 11:30 am Overreach much?
So, I'm a big fan of Sterner and Elser's Ecological Stoichiometry book - I was a convert who now believes that stoichiometry can sure explain a whole lot more than one would initially give it credit for (especially when it comes to making biotic interactions conditional). In the book, there's a great flow chart about how stoichiometry can explain 99% of ecological and evolutionary theory. I am highly skeptical. Then, I saw this. Early Cambrian food webs on a trophic knife-edge? A hypothesis and preliminary data from a modern stromatolite-based ecosystem. I haven't yet read it (I should be working on a review right now), but the abstract seems to say that the Cambrian Explosion was determined entirely by phosphorus ability, and they demonstrate it by showing that snail grazing is maximized at intermediate phosphorus levels. They link this together with the idea that, the Cambrian explosion linked with higher P availability. Subsequent extinctions are linked with dramatically higher or lower P values.

Their reasoning from the paper's discussionCollapse )

Is this an example of dramatic overreaching, or do you find some logic in all of this? Opinions? Can stoichiometry explain everything?
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Jan. 11th, 2006 @ 10:31 am (no subject)
Quote of the day:

"Science advances by the gall of graduate students." - Don Strong

On a "huh?" kind of note, I've been trying to puzzle out Mumby et al's recent Science paper. There's a good summary of it and it's implications by Ove Hoegh-Guldberg. To summarize, implementing marine reserves on coral reefs restores predator biomass. However, while herbivores will be reduced in size and density, due to the continued size escape of a few large grazers that do most of the grazing, there will be no trophic cascade. In reefs, this is great, as it means corals will not be overgrown by algae, and perhaps even suggests that in pristine reefs, most of the grazing is done by both many small bodied grazers and a scarce few predation-escaped large grazers.

Personally, I find this a bit of a mind-bender. I understand the importance of a few large versus many medium sized grazers, but the overall decline in grazer biomass is pretty large. I guess grazing in these systems way back in the day was determined by large sea-cows and turtles which have largely been driven to extinction, so, perhaps it isn't a surprise. Still, though...I wonder if this is general to terrestrial reserves? What about reserves in typically algal dominated systems?
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Nov. 28th, 2005 @ 10:11 pm (no subject)
Since, an introductory post was requested in the userinfo, here it is.

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Nov. 10th, 2005 @ 09:37 pm On ecology and paper companies
I'd like to talk about an idea that many environmentalists have about how printing companies and other factories are bad for the environment.

I have an idea in my mind that perhaps there is something more subtle than just "the evil engine of capitalism" at work here.
After working for 48 hours in a printing factory, I came to understand the real reason why factories are so notorious for clear cutting and destroying the environment. Inefficiency.

If things were more efficient, we would be losing half the amount of trees we're currently losing daily.

Read more...Collapse )

Now, if someone came up with a more efficient way to get what needed to be done done, I think there wouldn't be nearly such a ridiculous amount of waste at these plants. The question is how would one do that.
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Nov. 10th, 2005 @ 05:04 pm (no subject)
Does anyone have any suggestions for programs that can be used for calculating species diversity? I tried searching online, but all I could find were ones that required whole numbers (like species counts) and my data is based on biomass. I have been calculating stuff in Excel, but I know there is an easier way than entering the formula over and over (there is probably an easier way to do it in excel too).

Oh, and while I am asking questions...I know there are a couple marine people here, so does anyone have any suggestions for measuring tidal height besides using a meter tape and surveyor's gear. We know there is an easier way for this too.

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Oct. 3rd, 2005 @ 10:30 am Species Invasions, Biocontrol, and Aparent Competition
Today's issue of Ecology is filled with some neat stuff. One which jumped out at me immediately was Noonber and Byer's More harm than good: when invader vulnerability to predators enhances impact on native species, mostly as I've been thinking about interactions between invasives and their potential predators. In short, it uses traditional food web models (good ole' Lotka-Volterra and the like) and shows that the addition of a new competitor for a resource that is also consumed by a common predator decreases the region of paramater space where co-existence is possible. In other words, just because a predator eats an invasive species does not mean that it will exclude the invader while favoring the native. One new prey item eaten means that predators have more energy to reproduce and consume natives as well. Of course, there is a region of parameter space where both co-existence and exclusion of the native are possible, but given that invaders often arrive with some sort of advantage - better nutrient assimilation, faster growth, fewer parasites, etc - that biocontrol of an invader may actually lead to the elimination of the native species rather than the invader.

Thoughts? Do you like this approach? Any examples spring to mind that you'd care to discuss?
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Sep. 7th, 2005 @ 08:09 pm random thoughts
So I completely failed in the journal discussion department, but I have some random thoughts I have been playing around with that would be interesting to discuss because they have both ecological and societal implications. The system is marine, but I think I can relate it to a general ecology audience too.

In order for this to all make sense I provided a bunch of background info. Sorry that it is kind of long. impactsCollapse )
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