New Berkeley study on grass and global warming misses one very important issue

Caveat, no, it isn’t about “grass use” in UC Berkeley, and note the press release with the key word, “could” in the title.

From the University of California – Berkeley

Exotic Grass: At Tom's Point in Marin Co., Calif., near Tomales Bay, the exotic grass Holcus lanatus is common. Credit: Brody Sandel

Warming climate could give exotic grasses edge over natives

Invasive grasses are better equipped than natives to deal with increasing temperatures

California’s native grasses, already under pressure from invasive exotic grasses, are likely to be pushed aside even more as the climate warms, according to a new analysis from the University of California, Berkeley.

In the study, which has been accepted for publication in the journal Global Change Biology and is now available online, UC Berkeley biologists catalogued the ranges of all 258 native grasses and 177 exotic grasses in the state and estimated how climate change – in particular, increased temperature and decreased rainfall – would change them.

They concluded that many of the traits that now make exotic grasses more successful than many natives also would allow them to adapt better to increased temperature and likely expand their ranges.

“When we looked at current patterns, we found that warmer temperatures favor certain traits, and these are the traits possessed by exotic species,” said coauthor Emily Dangremond, a graduate student in the UC Berkeley Department of Integrative Biology. “This led us to predict that, if the mean temperature increases in all zones in California, there is an increased likelihood of finding exotic species, and an increase in the proportion of species in a zone that are exotic.”

The study was inspired by a 2008 class run by David Ackerly, a UC Berkeley professor of integrative biology, that focused on the role plants play in their ecosystem and how those roles may alter with climate change. This area of study, called functional ecology, is being used more and more by ecologists to predict the consequences of global warming.

“The ‘trait-based’ approach lets us test hypotheses about plant distributions in relation to climate without tying them to the identity of particular species,” Ackerly wrote in an email from South Africa, where he is on sabbatical. “As a consequence, the analyses can be generalized beyond California to other grassland areas.”

With grasses, the increase in exotics could make the state more prone to wildfires, since invasive grasses dry out in the summer more than do native grasses. Some grasses serve as reservoirs for viruses and other pathogens that attack food crops, while others more efficiently suck up water that would normally be used by other grasses and plants,

Dangremond is involved in a study of European beachgrass (Ammophila arenaria), which she has found harbors deer mice that eat endangered lupines. The beachgrass has invaded sand dunes along much of the coast in California, Oregon and Washington, she said.

For the current study, Dangremond and postdoctoral fellow Brody Sandel, now at Aarhus University in Denmark, divided California into 800 zones, and characterized all the grasses in these zones according to 10 distinct traits related to growth, reproductive and light capture strategies. These traits included grasses’ maximum height; plant and leaf lifespan; seed mass; month of first flowering; length of flowering period; specific leaf area, leaf length and width; leaf nitrogen concentration per mass and per area; and the grass’s specific photosynthetic pathway. The data came primarily from the updated “Jepson Manual: Higher Plants of California” published by UC Press.

Some zones in the state contained as many as 163 grass species, while others had as few as three. In some zones, two-thirds of all grasses were exotics. The researchers found that, in general, the higher the average temperature in a zone, the greater the proportion of exotic grass species.

Exotics differed significantly from natives on seven of the 10 traits in ways that made them more adaptable to higher temperatures. For example, exotics tended to be taller, have longer and wider leaves, higher specific leaf area, higher nitrogen mass in the leaves and higher seed mass, and were less likely to be perennial. Noxious invasives were even more extremely adapted to warmer temperatures.

These traits account for the success of invasive exotic grasses, Dangremond said. Taller grasses, for example, give exotics more light-capturing ability and the ability to outcompete natives for light. Similarly, the larger seeds of exotic species could give these grasses a competitive advantage at the seedling stage.

“As climate changes in the coming century, which at this point is quite certain, this means we expect the distributions of the grasses to change as well,” Ackerly wrote. “Sadly, what this predicts is that the alien species that already dominate the Central Valley and other hotter regions of the state will become even more widespread in the future.”

“I hate to be a doomsayer, but the problem is getting worse because of humans,” Dangremond said. “Humans promote the spread of invasive species by disturbing areas and letting weedy species come in, and grazing herbivores like cows and elk tend to have a negative effect on native plants anyway. Native species really have a lot to contend with now.”

For more information:

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Here’s the issue. Former State Climatologist Jim Goodridge shows that most of the warming since 1900 in California is in the most populated areas.

Unfortunately, these studies don’t seem to take things like this into account, choosing instead, blanket assumptions on temperature.

But when they say “”I hate to be a doomsayer, but the problem is getting worse because of humans,”  they are partially correct. As Jim Goodridge shows, UHI driven by human population does in fact create a warming trend in California. I suppose that means weeds in our cities and backyards might get more common than native grasses, but isn’t that the case anyway?

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73 thoughts on “New Berkeley study on grass and global warming misses one very important issue

  1. Has not California had a cooler than usual Summer?

    I notice we are meant to feel ever more guilt for being born as humans!

  2. If you take away the emotional loading of “invasive”, this is simply a tautological statement of basic evolution. A species or variety that moves into an area is doing so because it’s more adaptable to different conditions. (If it wasn’t adaptable, it couldn’t “invade”.)

  3. AGW is good for evil grass, bad for nice grass. Apparently.

    How does warming know-heat isn’t this smart, or diabolical-to only help the bad life forms and hurt the good ones? The idea that this is the case, which is the impression one gets reading the various news stories, leaves me, and I hope any sentient individual, incredulous.

  4. If the goal were the genetic purity of North American grass species, I’d say that ship has sailed a long while ago. We have thousands of grass species in Colorado, and hundreds of what the researchers are calling “exotics”. The “invaders” no doubt came in waves: on the moccasins of what we now call natives who crossed the Bering Straits; or on the cloaks of explorers from Europe during the ages of exploration.

    One grass we have a lot of in Colorado, and doing fine in this era of soaring greenhouse temperature (/ sarc) — despite being a short grass — is a brome everybody calls “cheatgrass”. Nobody seems to like downy brome because it affords little forage, and turns browns early in the summer. One story of its etymology is interesting to me because it suggests its age. Cheat, comes from the word eschete, which is an old French variant of “fall”. In Medieval times, lands would fall back to the Lord of the Fee, if their designated inheritors failed to be recognized as legitimate. Such property became known as eshete lands, and they often fell into disuse, their crops going to waste, and the less favored grasses moved in: the eschete grasses.

    So, FWIW, the invading aliens are already here… living amongst us…

  5. Thanks for the historical temperature data sorted by population! Very interesting, and potentially benifical when discussing social justice items with the powers that be in the state.

    I can think of lots of interesting ways to sort and evaluate the data further. By chance has Jim Goodridge evaluated the data sets further? Asphalt vs concrete surfaces come to mind as something I’d like to see data on, etc.

  6. Eco-systems are complicated. I attended a talk about native plant protection recently in the bay area and learned a few things. All these comments are related to populated areas. One: fire protection steps may adversely affect some native grasses. Tall dry grasses are no-no in these parts. They are always mowed down by the start of the dry season. This would benefit shorter species. Two: plants are affected by the insect and wild life population. We have an explosion of deer population. They eat certain plants and won’t others. For example, the star thistle, which is a non-native plant, thrives because deer won’t eat them. These factors alone can select what species will thrive and what will not. They have very little to do with temperatures.

  7. Every drop in CO2 has been hand in hand with a plant evolution…
    . one of the biggest drops was when grasses evolved

    Of course more CO2 is better for grasses………………..

  8. in the land of fruits and nuts…grass is king (queen?)

    Ben D Hillicoss

    ps so glad I moved to Maine and out of California

  9. Well darn, I guess that leaves NW California out in the cold. It’s been getting cooler the past 7 years, and those pesky native grasses stay green all year. Especially if you pull up the invasives and nix the expesive herbicides, or stop weed-whacking everything to bare dirt death.

  10. “As climate changes in the coming century, which at this point is quite certain, this means we expect the distributions of the grasses to change as well,” Ackerly wrote. “Sadly, what this predicts is that the alien species……….
    ================================================================

    lmao!!! You mean, sniff, that the earth, the flora sniff…sniff and the fauna isn’t static!!! sniff, sniff, waaahhhh…… waaahhh!!!!

    Yes, sadly, very sad.

    They should do like Kansas did. Just 10 miles west of here, at the junction of U.S. 169 and U.S. 400, there is a rest area. And, in that rest area, there is a patch of ground that has native prairie grass in it. We’re very proud. We’ve got signs and explanation of the flora. I kid you not. Imagine a traveler, having gone the width and breadth of Kansas, seeing nothing but miles and miles of prairie grass, gets to stop and see…… prairie grass. Preserved for posterity, I suppose. I’m kinda surprised Cali didn’t think of something that insipidly stupid, first. Prolly, someone from Cali that imported to here……
    (No offense to the sensible people still left in that state……. both of them.)

  11. Oh come on, Anthony. Everyone knows BC (British California) grass is better than mere California grass; and, if this is true, it will be even better. Or have I missed something :)

  12. No matter mankind’s role in the changing climate, 2°C or .1°C, here sounds the clarion call of the midget minds, wanting the safety and security of an unchanging environment. A new plant or a new animal appears on the scene and all that was taken for granted is out the window. It strikes terror in the hearts of those seeking the safety and comfort of the known, the familiar.

    Well, guess what … that’s the way the universe works and has worked for over 13 billion years … never ending change.

  13. Here’s the issue. Former State Climatologist Jim Goodridge shows that most of the warming since 1900 in California is in the most populated areas.
    ———-
    Well UHI is a reasonable explanation for this. But it is not an open and shut case because “correlation is not causation”.

    An important factor is that cities tend to be coastal. And if coastal conditions cause a greater temperature trend then that could represent an alternative explanation that makes equal sense or is at least a contributing factor.

  14. “For example, exotics tended to be taller, have longer and wider leaves, higher specific leaf area, higher nitrogen mass in the leaves and higher seed mass, and were less likely to be perennial. Noxious invasives were even more extremely adapted to warmer temperatures.”

    Since they’re generalizing, let a real physiologist have a go….

    1. The most competitive invaders are perennials, not annuals. Fire kills annuals, not perennials. Lack of natural burning favors invasive annuals, native or not. Fire is native, lightning is a natural occurrence. Go figure.

    2………taller…..longer…..wider leaves………… higher leaf area……….higher seed (yield) mass
    = INCREASED YIELDS. Whoa, did i just write that?

    3. Wheat is a non-native grass. Corn is a non-native grass. Oats. Barley. What’s your point. Who cares where it comes from?

    4. Different species of rusts, viruses, bugs etc. attack native and non-native grasses. Deal with it.

    These folks just don’t like people. We should live like the Indians. Let the populace eat cake. Etc.

  15. Yes, Anthony, always point out caveats in papers and articles. The more times, the better. Draw attention to their fudging uncertainty, while usually letting MSM headlines blare abject certainty.

    It is dishonest for the scientists to let such headlines pass.

    It IS honest, though, if the caveats are in the titles/headlines. But still, WUWT should point out the iffy-ness for what it is – them saying they don’t really KNOW.

  16. By the way, one of the most efficient grasses known to man is called johnsongrass. It is classified as a noxious weed in most states. Under certain circumstances, it can cause death when eaten by cattle and horses (long dry spells with high soil nitrogen availability). We could save a ton of expelled CO2 on annual plantings if we taught people how to raise it instead of outlawing it. Guess they’re being a bit hypocritical.

  17. If I recall my history correctly, California has already had most of its native grass overrun by the invasive species several decades ago. I doubt it can get worse. Everything seems to be fine so far.

  18. I have just come back from northern California and never in my life have I experienced such massive temperature variation within such short distances. 20F in less than a mile, and that was the case all over – from the Sonoma coast to Big Sur, from the Bay area up to Napa. How anyone can claim an accurate T record for that part of the world is beyond me.

  19. Biologists were the first to become post normal scientists. Anything good for humans is bad for the plants and animals. They are not climate scientists but they are certain that:

    ““As climate changes in the coming century, which at this point is quite certain…!!!!

    Quite? Isn’t this a bit mealy mouthed. Is she pregnant or not? Also, it is not a scientific paper that uses terms like “sadly” “hate to be doomsayer but humans….”

    As a geologist and an engineer I never write such stuff: Sadly, the comet impact killed off the dinosaurs. I hate to be a doomsayer but hominids and humans wiped out the wooly mamoth and the latter brought asian plant seeds to North America. I don’t trust a biologist under 150 years old.

  20. MJ says:
    July 29, 2011 at 3:59 pm

    We just need more cows, sheep, and goats in California…
    *****
    Wow MJ, I didn’t know you could burn sheep!

  21. Another important question: does a COOLING climate benefit native grasses?
    If not, the non-native grasses win EITHER WAY… and the study is entirely moot regardless of warming…

  22. Off Topic but Breaking News….Tropical Storm Don just virtually collapsed as it moved inland. Low level circulation still evident south of Corpus but the deep convection has collapsed. Sorry moisture starved Texas. I’m sure some re-generation of shwr/t-storm activity is in the offing around the low level center tomorrow during the heating of the day but widespread rains look unlikely now.

  23. In Australia, buffalo grass from the USA is classified as a pest, even though livestock producers love it. Similarly, buffel grass from Africa is called a pest but it has saved many livestock producers in Australia.
    change the seasons and grazing patterns and the flora changes. Nothing to do with CAGW causing it, it is a response to various factors.

  24. of course if rural areas warm by 1C and urban areas warm by 2C, then the fact that urban warms faster than rural, doesn’t negate the warming that happens in rural areas.

    ““This led us to predict that, if the mean temperature increases in all zones in California, there is an increased likelihood of finding exotic species, and an increase in the proportion of species in a zone that are exotic.”

    classic If, then.

    If it warms in a zone ( be it urban or rural or whatever) THEN you will increase the likelihood of seeing plants there that like it warmer. if, then.

    If it doesnt warm more in rural, then of course you’re likelihood will not go up.

    Seems pretty basic: if, then.

    the question of course is … will it? or has it?

    grassmometers

  25. I am happy to get to the source (paper, or report?) of the Jim Goodridge’s Figure. Thanks.

  26. LazyTeenager-Actually, physically speaking one would probably expect coastal sites to warm less than inland. There is generally a tendency for oceans to warm or cool less than land areas expected due to the difference in heat capacity of the oceans versus land, and much as you will tend to find that there is less seasonal variation near coastal areas than inland, but more than over the oceans themselves, one would expect long term trends to be smaller at the coasts than farther inland, although presumably larger than the sea surface itself. In other words, we expect the opposite of your proposed alternative explanation. :)

  27. Coming from an agriculture background, I have to say that the study deserves a big “So What! What’s the Big Deal?” The reason behind the increase in forest fires is the federal government’s mismanagement of the forests for allowing underbrush to grow unabated. The Indians of time-past exercised, indirectly, proper forest management with the practice of starting fires during the fall season to force game down to the lower elevations for ease of hunting, a habit which eliminated the heavy growth of underbrush that serves as gasoline for a huge fire.

  28. Those wild oats at Point Reyes are terrifying!
    What shall we do, Rhett, what shall we do?

  29. This study is exactly wrong.

    More CO2 gives ALL grasses a disadvantage because more CO2 takes away the advantage that C4 grasses had over C3 broad-leafed plants, trees and bushes when CO2 levels are low as they have been for the past 24 million years.

    Grasses are not as efficient as broad-leaf plants in total biomass volumes except when CO2 levels are very low and/or when it is hot and/or when it is dry. When CO2 levels are low, C3 broad-leafed plants need to open their “breathing” stomata more. This means that there can be more envirotranspiration of water and broad-leafed plants can die off if there is not enough rainfall, especially if it is hotter. So it is hot and dry and low CO2 that gives grasses an advantage.

    High CO2 means grasslands are doomed because C3 broad-leafed plants will out-compete them except for perhaps hot and dry locations like the Saharra where grasses will now grow instead of desert conditions prevailing.

    In addition, greenhouse theory is based on increased temperatures increasing the water vapour in the atmosphere which also means there will be more rainfall everywhere (other than a 9 day delay when water vapour accumulates in the atmosphere – the increased drought propositions are not really based on the science – rainfall will increase everywhere).

  30. “I hate to be a doomsayer, but the problem is getting worse because of humans,” Dangremond said. “Humans promote the spread of invasive species by disturbing areas and letting weedy species come in, and grazing herbivores like cows and elk tend to have a negative effect on native plants anyway”.

    Smoking grass can make a person depressive and seriously delusive.
    Especially in California.

  31. Pathetic – people actually feel pride in getting paid to produce such mindless garbage?
    How many things can I find wrong with this pile of elk dung?

    “Humans promote the spread of invasive species by disturbing areas and letting weedy species come in, and grazing herbivores like cows and elk tend to have a negative effect on native plants anyway. Native species really have a lot to contend with now.”

    Bad ol’ humans up to their tricks again huh? But wait, what about animals and birds – they have no effect on migration of ‘weedy species’? They don’t ‘disturb areas’? Come on!
    Grazing herbivores have been in America for eons – how did the poor native flora survive all this time? Apparently they have to ‘contend’ with more now. Come on! Emotional claptrap. Get a life (and a real job) UC Berkeley biologists.

  32. Pretty scary…until you think about how California’s “native grasses” got to be California’s native grasses.

    James Sexton says (July 29, 2011 at 4:38 pm): “(No offense to the sensible people still left in that state……. both of them.)”

    None taken. :-)

  33. Speaking of grass and Berkeley……

    You can oft times smell grass burning when passing through Berkeley. But that’s a different grass.

  34. Hi all –

    One of the original authors on the paper here. It’s interesting to see what you all have to say about this. I’d just like to make a few things clear.

    First, the results in the paper are a prediction based on data. They are not politically, socially or economically motivated. We don’t think people are “bad”, “evil” or anything like that. The results of our analysis could certainly have gone the other way – it is possible that temperature increases will HELP some native species. It seems that’s not the case for grasses.

    Why should you care? Well, there is some economic value in native grasses (as forage for livestock, etc.). There is also a conservation reason. I happen to think there is value in maintaining, at least somewhere, the state’s plant species. This includes grasses, why shouldn’t it? You might disagree – in your mind native and exotic plants might have equal value. That’s a totally separate question from whether the results of the study are valid, though.

    The graph in the OP is interesting. It suggests that our prediction will be strongest in heavily populated areas.

    “timetochooseagain says: AGW is good for evil grass, bad for nice grass. Apparently.

    How does warming know-heat isn’t this smart, or diabolical-to only help the bad life forms and hurt the good ones? The idea that this is the case, which is the impression one gets reading the various news stories, leaves me, and I hope any sentient individual, incredulous.”
    If anyone were claiming that temperature changes were planning to hurt certain species, you should be incredulous. Fortunately, we aren’t. Temperature changes are likely to hurt some species and help others. We asked a simple question – which groups will be hurt, and which helped. We got an answer to that question.

    “Bill Parsons says: So, FWIW, the invading aliens are already here… living amongst us…”
    That is true. In fact, we show data in the paper estimating how the number of exotic species in the state has increased through time.

    “Lonnie Shubert says: If I recall my history correctly, California has already had most of its native grass overrun by the invasive species several decades ago. I doubt it can get worse. Everything seems to be fine so far.”
    True again! Much of CA is already covered by exotic species. However, there are parts of the state where that is not true, particularly as you move into the mountains. Whether that is fine or not depends on whether you place value on conserving native species.

    “Dave Stevens says: Another important question: does a COOLING climate benefit native grasses?
    If not, the non-native grasses win EITHER WAY… and the study is entirely moot regardless of warming…”
    Yes, our results suggest that cooling should favor native species.

    Anyway, as I said, it’s very interesting to see all these comments. I’m happy to continue this discussion, and will try to check back for responses.

  35. Bill Illis-”the increased drought propositions are not really based on the science – rainfall will increase everywhere).”

    Actually this is not quite right. While indeed models project total precipitation over the whole Earth to increase, they differ wildly about the distribution of changes in precipation, and do not, in fact increase it “everywhere” but have some areas lose and some gain, in net more gains than losses. Mind you, they vary a great deal about what areas will lose and which will gain, but they do all lack uniform increases. Additionally, you are incorrect about the reason why precipitation increases overall-it is not because of higher humidity but rather higher evaporation, which always equals precipitation globally. The alleged wv feedback is not a consequence of evaporation, incidentally, even though many scientists explain it that way-it is actually because saturation vapor pressure of wv is higher at higher temperatures, and models have wv follow the Clausius clayperon models have water vapor follow cc scaled to the level of relative humidity which is held quasi constant or even increases in models (which corresponds to forcing wv to even more tightly follow cc) and this independent of the evaporation question.

  36. This is a case of being smarter than the problem. We create a native grasses exchange program set up where all the nations of the world export their best native grasses to another country where, according to this article, they will prosper. This will ensure that all nations have the very best non-native grasses in abundance. If it was good enough for Estonia, it’s good enough for me, I say. I hope they appreciate our Kentucky Blue grass, where ever it goes.

  37. Thanks, Mr. Sandel, for commenting. Welcome!

    I’m curious about the assumption that with warmer world there will be less precipitation. Is that based on data that have been seen in California or is there a particular model you used as the basis for the temperature-rainfall connection?

  38. Hey brody thanks for stopping by. I found the reaction to the paper be rather odd. But I’m curious about the data and the 800 zones. Any way I can get my hands on that?

  39. California has not had a “natural” landscape for several millennia. The “native” grass lands of California were structured to a very great extent by seasonal fires, largely started by the indians. The “immigrant” invading grasses are annuals that tend to mature earlier and have shallow roots that are killed by fire. The “native” grasses were largely perennial with deeper root systems that could survive fire. There also many more species of flowering annuals and perennials around. Suppression of seasonal burning is the single biggest problem faced by the native grass. If we really wanted to help it, we could star setting seasonal fires in the fall, but I can see the regional air boards agreeing to that – not.

  40. Maybe native grasses will respond better to higher CO2 levels…. But I ‘spose they didn’t look for that?

  41. Hello again,

    Thanks for your responses. It’s a little scary jumping into a discussion like this, but I really think we won’t make much progress unless people can have honest debates (even with those they disagree with). So, I thought I’d give it a go!

    To your question, Eric: My understanding is that precipitation changes have much greater uncertainty than temperature changes. Various models have predicted either increases or decreases. In the paper, we said that changes in precipitation are uncertain, but are likely to include modest decreases in some areas. This was based on the work of Cayan et al. (Climate change scenarios for the California region), which can be found here: http://www.springerlink.com/content/6rr76v0l151283p7/. They evaluated different climate models and emissions scenarios. For the results of our paper, though, precipitation is not likely to matter a great deal – temperature was by far the dominant control on grass distributions.

    To Steven: We’re certainly open to sharing data. Some of the data that we used is in databases that don’t belong to us (trait databases), but most of it is, in fact, publicly available. Feel free to contact me directly and we can discuss what you need (my email is easily found on the web).

    Finally, to dp: I suspect you might have been joking here (at least a little?), but this has actually been seriously proposed. It is often called “assisted migration”. It’s VERY controversial among ecologists, particularly those who are concerned that we don’t know enough about most species to make reasonable guesses about where they should go, and what they would do when they got there.

  42. I thought greater bio-diversity was a good thing, with a greater number of species of both perennial and annual grasses, the effects of a greater range of climate variations will be dampened, as the micro climates of sections of fields, allow an even greater growth rate for the composite culture as opposed to a more monoculture blend on natives.

    Different species have peak growth times under different conditions, and the sod is almost always a composite of all species, each finding its preferred niche of soil type shade and moisture requirements. Having converted Kansas marginal crop land back to graze able cover crops starting with seeding selected grasses and alfalfa, and watching what the blend of grasses and weeds end up like over 25 years, under different grazing pressures, I understand the slow transition to better adapted species. There also is a shift from what I planted as the bare dirt is more covered with sod, the auto reseeding of legumes and thistles in bare dirt, yields to a fuller blend of all grasses as the top soil improves, insects and earth worms need a constant supply of edible organic matter that builds soil tilth and fertility.

    The addition of small flowering weeds and wild flowers supports flying insects, bees, wasps, spiders, praying mantis, grasshoppers, crickets, and many other segments of the natural food chain, that benefit from the greater diversity of the vegetation that supports the whole system. Birds, small mammals, rodents, squirrels, chipmunks, groundhogs, and the local predators, and scavengers.

    In the 25 years I have spent returning my 160 acres back to a more sustainable bio diverse habitat, I have noticed that no one thing takes over, but many share the times of the year they grow and bloom, change where they prefer to grow in wetter and dryer times, colder and warmer years.

    Rough weeds are there to make a fast growth and cover the bare dirt with leaves, stalks, and roots to stop erosion in the early stages of the land reclamation process, the grasses build sod to hold and filter soil crumbs out of the runoff, until the buildup of organic matter is faster than the decay into top soil, and the absorbancy of rain fall is enhanced. More variety just gives more plants different seasonal windows to do their peak growth, so in the end there is something sprouting, shooting up, blooming, dying and decomposing at all times. Just a wise people select there friends, plants share there space, water, sunlight, and nutrients with their neighbors as well.

  43. grazing herbivores like cows and elk tend to have a negative effect on native plants

    Well now, the time has come to have a negative effect on my breakfast.

  44. And exactly who is paying for this unneccessary “research”? You, friends — you. As a nation, we are currently locked in a struggle of whether or not we continue to fund such nonsense — and I say, we have more importantant priorities. This is a fascinating discussion; I side with the more pure evolutionary proponents, but this is hardly the most important issue on the table at the moment. Many of us need to be expressing our heartfelt opinions not only here, but in forums that can have an impact in the present.

    It’s only a matter of time now until the CAGW fraud becomes the past. Not encouraging y’all to end the conversation, but could some of the more intelligent posters here start foccusing your attention on what is happening within the US Government? Apoligies to Anthony, who has done a spectacular job in unhorsing the libs on “climate change,” and may God bless him. He has won.

    Let us rejoice in the successful conclusion of this battle and concentrate our efforts on the far more real battle ahead, defeating this illiberal mindset at its roots.Much more is at stake here than our opinions on climate change. L

  45. Aren’t those “invasive species” native to neighbouring regions. So effectively heating is improving their range. Presumably, climate change will also allow those threatened “native species” to spread to areas that were previously inhospitable to them.

    Surely the only real conclusion is that climate change results in movement of the “native areas” or all species. Hardly an earth shattering conclusion.

  46. They say……. and grazing herbivores like cows and elk tend to have a negative effect on native plants anyway. Native species really have a lot to contend with now.”

    Certainly in the UK (which used to be entirely forested) and I guess it applies elsewhere, without grazing animals, grasslands turn to scrub and scrub turns to trees & forest and forests are not especially well known for their ‘grassiness’ Trees are not grass – its the grazing animals that make the grasslands.
    As usual, they know everything but understand nothing.

  47. Does not this ‘research’ ignore the fact that the native grasses survived previous warmer periods? If this research were valid then there would be only the invasive species growing and these would then be called ‘native’.

    These people have too much time on their hands.

  48. I do appreciate the caveats–both Anthony’s and the authors’. Much of scientific research is based upon measurements. All measurements have uncertainty. Sometimes the relative uncertainty is small; sometimes it’s humongous.

    Whenever a measurement is reported, the estimated uncertainty should also be given. This can be done explicitly, or it can be done indirectly, by using the correct number of significant figures. Discussing uncertainties is definitely NOT the same as being mealy-mouthed or wimpy. Caveats are an essential part of scientific honesty, even though some policy makers don’t want to hear about them.

    About the life sciences. Biologists are probably the most honest of all the scientists riding the AGW gravy train. How so, you ask? Unlike climate modelers, climate change biologists START with the assumption of global warming, and they use the estimates from the IPCC reports, and they’re very upfront about that fact. Then they do their level best to make projections about the effects of putative global warming on individual species, and on ecosystems as a whole. In other words, they’re playing the If-Then game.

    If biologists don’t feel comfortable stepping outside the boundaries of their specialties, and screaming, “BS” at the climate modelers, I can’t fault them for that. On the other hand, some biologists have too much Gaian religious fervor, which is both off-putting and unprofessional.

  49. Did anybody notice the green cult is all about stopping evolution?
    Climate is evoling – we must stop it!
    Plants are being replaced by other plants that are better adapted to environment – we must stop it!
    Species is becoming extinct because it’s not adapted to its environment – we must stop it!

    Sorry to say that but evolution is what caused us being here. What we consider “normal” grass was exotic grass way back when it became replacing its less adapted predecessor. And unadaptive species were always becoming extinct naturally. We can’t stop evolution. And if we stop evolution of anything, it will become unadaptive and it will be extinguished by nature.

  50. StuartMcL says: “Surely the only real conclusion is that climate change results in movement of the “native areas” or all species. Hardly an earth shattering conclusion.”

    That’s not quite the conclusion we drew from the data. We predicted that the native areas will shrink, and where natives and exotics are mixed together (which is actually much of the state), exotics will make up a larger portion of the community.

    Pete from the UK says: “Certainly in the UK (which used to be entirely forested) and I guess it applies elsewhere, without grazing animals, grasslands turn to scrub and scrub turns to trees & forest and forests are not especially well known for their ‘grassiness’ Trees are not grass – its the grazing animals that make the grasslands.”

    You’re right – in many areas grazing (or fire) is required to maintain grassland. Our intention was to note that heavy grazing (as opposed to light grazing) can favor exotic species. Sorry if that was unclear.

    John Marshall says: “Does not this ‘research’ ignore the fact that the native grasses survived previous warmer periods? If this research were valid then there would be only the invasive species growing and these would then be called ‘native’.”

    That’s a good question – certainly these species have been through climate cycles in the past. There are many possible answers to it, but two major ones that come to mind are that 1. it hasn’t been as hot as it is expected to be in 100 years for a very long time, and 2. these native and exotic species have not been in contact with each other for a very long time. Change, as Leon Brozyna pointed out above, is the name of the game. It’s our job to try to understand how and why things change, so we can make useful predictions.

    Thanks for the thoughtful post, Mr. Fields. I thought your description of uncertainty in science was very well put.

  51. MJ says:
    July 29, 2011 at 3:59 pm

    We just need more cows, sheep, and goats in California
    +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    Nope. their farts will create more methane which will be baaaaaaaa’ d (sorry)

    On a more serious note, your participation is welcomed and appreciated Professor Sandel. It is a shame that others are not willing to do so.

  52. No one knows how many thousands or tens of thousands of years the native americans used fire to control their environment – California was know as “the land of smoke” to the first Old World travelers to it from their ships, as far as they traveled up and down the coast they could see it was continuously on fire. In Oregon the natives proudly presented to the white newcomers the vast prairies they had carved using fire. And in Maine, it was noted that natives use of fire had created an environment so open that a man could drive a horse and carriage for 50 miles between the wide-space trees… Amusing that such attention is paid to grasses and other “exotics” that have been arriving and leaving for hundreds of thousands of years, as the glaciers have come and gone and come again… Nature is eternal and cannot be broken and it is only the infinite hubris of man to believe we can ever know what SHOULD grow here and what SHOULD NOT grow here… Here is a thought – in all of North and South America, over the millennia, EVERY brief environment has changed ALWAYS to another brief environment. And another. And another. That grassland? Once a forest. That forest? Once a grassland. That swamp? Once a desert. That desert? Once an ocean. And so on. Only our incredible short-sightedness convinces us that any environment we see is “eternal”.

    I say enjoy the interglacial while it lasts.

  53. wonder how the spread of the proposed GM grasses for home use , as well as the already spreading GM golf couse stuff is going to seriously crimp ALL other grasses styles?FDa admitted its long lost the plot re regulating anything. and no GM plants ever! stayed put or not outbred.

  54. Got to hand it to Academics these days, they sure do know how to guage the climate in the publication business. Either that, or there’s a lot of ver sympathetic editors that are bending over backwards to help these folks get published. Wouldn’t make too much of the wordsmithing, it’s all academic. What people “publish” and what they “believe”, really, truly, with their whole mind and soul, is usually, almost always, normally –or not– quite different. The Chinese have a very old time-tested system that’s of tremendious value when judging where people are coming from. There’s the Outer Self that we show to the Public. There’s the Middle Self that we show family and our closest friends. And, there’s the Inner Self that we show no one; it is hidden from all but ourself. This paper was written by Outerselves communicating with the Public. It should be approached carefully, very carefully, and studied for whatever reason you think it may be of value to your Public Self, Middle Self, and Inner Self. Buyer Beware!

    PS: Try the Chinese Method. It really does help you see the World in a very different light. Honest!

  55. Similar to the saying that a weed is a plant in the wrong place, I suppose for Californians Holcus lanatus is an ‘exotic’.

    It’s common name in the UK is ‘Yorkshire Fog’ – and very pretty it is, too.
    However, it must be getting pretty cold in California for it to thrive:
    “In Britain, plants of Yorkshire fog require vernalization in order to flower, with a minimum exposure of 25 days at a temperature of 5°C.
    (My bold)
    Link:http://www.gardenorganic.org.uk/organicweeds/weed_information/weed.php?id=81

    Regarding Ammophila arenaria – this is Marram grass, and has been and still is widely used to stabilise sand dunes. Chances are, this particular species has been imported, to do just that.

    These two particular species caught my eye, but given their wide spread, latitudinally, I am not so sure they ought to be used as indicators of warming.
    It gets pretty nippy in Yorkshire, come the winter …

  56. Considering that long-term predictions of climate models are unreliable, however hot it’s expected to be in 100 years is so much hand waving. In the meantime, changes in precipitation patterns could transform those grasslands into forest or desert.

    With grasses, the increase in exotics could make the state more prone to wildfires
    Really? It would be easier to judge if this were quantified. How much greater is the risk? Which of the 800 zones face this greater risk? What percent of the state would be affected? Is the increased risk significant? Wouldn’t the “increased” risk in wildfires simply be a return to historical conditions? Aren’t there native vegetation that require fire for germination and so forth, such that the increased fire risk is beneficial to their survival—or is the focus simply on grasses? How do the exotic grasses affect native non-grass species? Is there any benefit to the exotic species—which include wheat, corn, oats, barley, rice (wild and Asian), rye? Speaking of which, were any of the 800 zones dominated by commercial farming?

  57. Had this same argument once with a Koolaid drunk greenie who insisted that a certain species of grass was “invasive” in Northern Arizona. He was attempting to enlist “volunteers” from the staff to scourge the woods with him on a search and destroy mission to eradicate “invasive species.” He never made the connection that within the past 2000 years or so, the entire area had been covered for thousands of square miles with volcanic ash. EVERY species currently growing there (including the 3 and 4 foot diameter Ponderosa Pines) are “invasive” to the area within that time frame. That would also include the Native Americans and modern humans who slowly returned to the area after the volcanoes INVADED their native homelands! Brings to mind the phrase “nature disaster” is an oxymoron; only humans have disasters when they ignore the forces of Nature! Guess that makes me a greenie, too!

  58. MJ says:
    July 29, 2011 at 3:59 pm

    “We just need more cows, sheep, and goats in California”

    Yes. Get enough goats and California won’t have an exotic grass problem – nor a native grass or weed problem either! The goat doesn’t graze; it pulls anything green out by the roots. Goats equal instant desert. You just have to look at what has happened to great stretches of Southern Africa over the last six or seven decades.

  59. I notice the visiting author(s) don’t respond to the observation that their use of emotive evaluations like “sadly” “hate” “doomsayer”, etc., is totally inappropriate. This is just Berkeley Science. Not the real thing.

  60. Brody said:

    Finally, to dp: I suspect you might have been joking here (at least a little?), but this has actually been seriously proposed. It is often called “assisted migration”. It’s VERY controversial among ecologists, particularly those who are concerned that we don’t know enough about most species to make reasonable guesses about where they should go, and what they would do when they got there.

    Actually, I was alluding to the well known and oft repeated proverb: The grass is always greener on the other side of the fence. It reflects my pragmatic view of invasive species – they are called that because the species has no naturally occurring predator in the new environment. In my ‘yoot’ growing up in Hawaii we were often reminded of invasive species brought to the islands and I recall even then, and that was in 1957, that all species in Hawaii are invasive but some invaded a long time ago and seem to get a free pass.

    So these invasive grass species will, one day, have been here long enough that they are considered native. I’m already past that.

    More grist for the proverb mill: Anywhere they hang their hat is home. Any abundance will attract a predator. Nature abhors a vacuum.

  61. Brian H says “”This is just Berkeley Science. Not the real thing.”

    Not a wildly scientific response there – and you criticize others for having a bias?

  62. Richard Holle says “I thought greater bio-diversity was a good thing,”

    Ask the folks dealing with Asian Carp or if that is a good thing.

    Interesting Cornell study referenced here;

    “The broader issue is that without attention and action, invasives—either
    plant, animal or even viral—can continue a march, easily transferring from watershed
    to watershed. The costs are astronomical. Four years ago, Cornell University
    researchers pegged the annual price tag of environmental losses and damage
    due to all invasives at nearly $120 billion. That figure has likely climbed given an
    accelerated rate of spread and increased amount of species that have made their
    way into the U.S. Those same researchers further reported that 42 percent of the species
    on the threatened or endangered species lists are at risk primarily because of invasives.”

    http://www.seagrant.noaa.gov/focus/documents/2010NOAASG_NatStories.pdf

  63. What is sad is that minds are being wasted on this kind of trivia.
    Lots of study without producing anything other than fear.

  64. Ok brody thanks. It might be a bit as I have other projects looming. But it’s good to know the data is somewhat available. I have some ideas for it

  65. Amino Acids in Meteorites says “You can oft times smell grass burning when passing through Berkeley”.
    I was fortunate to visit Berkeley in 1971. It was certainly an eye opener to this young (naive) Australian pasture agronomist (grass mechanic) at the time. I thought it was fantastic that large numbers of the students were apparently endorsing my profession – as they were walking around with big lapel badges boldly stating that “Grass is a Gas”. I acquired several of the badges to take home for my professional colleagues to wear when visiting local landholders. Back in Australia it was a few years before I became aware of the same sweet smelling smoke wafting through the student dormitories of our University campuses.
    Incidentally the exotic grasses in California are said to make a significant contribution to the State’s biodiversity. But don’t mention that to green zealots who believe plant diversity only refers to endemic plants.

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