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?
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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.
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.
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.
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.
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.
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.
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.
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.
Anthropogenic Global Warming could lead to hemroids.
We know it requires a proctologist.
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.
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!
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 …
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?
It is difficult to see how this is not cargo cult science.
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!
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.
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.
Brody said:
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.
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?
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
What is sad is that minds are being wasted on this kind of trivia.
Lots of study without producing anything other than fear.
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
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.