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
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:
- Climate change and the invasion of California by grasses (Global Change Biology, 7/13/11)
- Climate change puts ecosystems on the run (press release, 12/23/09)
- Climate change could severely impact California’s endemic plants (press release, 6/24/08)
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?
We are already seeing invasive grass in California – being planted by invasive illegal aliens.
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.
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.
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
I am happy to get to the source (paper, or report?) of the Jim Goodridge’s Figure. Thanks.
BREAKING NEWS!!!!!!!!
Climatologists discover evolution. Man to blame.
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. 🙂
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.
Those wild oats at Point Reyes are terrifying!
What shall we do, Rhett, what shall we do?
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).
“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.
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?
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.
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. 🙂
Speaking of grass and Berkeley……
You can oft times smell grass burning when passing through Berkeley. But that’s a different grass.
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.
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.
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.
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?
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?
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.
Maybe native grasses will respond better to higher CO2 levels…. But I ‘spose they didn’t look for that?
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.
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.
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.
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