Air Pollution harms Native Chaparral Plants and increases the Wildfire risk

Photo: National Park Service.

This was certainly no surprise to me. I have been wondering about this possible phenomena nitrogen enrichment actually degrading native vegetation for a couple of decades now by destroying the underground mycorrhizal network and creating a more favourable nutrient enriched soil which converts the healthy symbiotic mycorrhizal fungal grid system to a bacterial one that favours non-native weeds (Ruderals). Well low and behold there are finally others who've gotten a clue about this by actually researching this very real possibility. The study which was done in the Santa Monica Mountains did indeed show harm not only in the degenerative effects of Chaparral native plant seedling regeneration, but also a favourable system for various weeds and other non-native grasses which are labeled as flash fire plants. The photo above right shows Interns measuring plots of California Sagebrush that have been injected with various levels of nitrogen as part of a three-year study to learn how air pollution is impacting native plants and increasing the fire risk. Below is the actual article:

Date: January 14, 2014  

Contact: Kate Kuykendall, 805-370-2343 

THOUSAND OAKS, Calif. – Initial results from experiments conducted in the Santa Monica Mountains indicate that high levels of nitrogen may adversely impact native plants and, by extension, increase the risk of wildfire.

"No one will be surprised to learn that our data shows increased air pollution on the eastern end of the mountains, closer to Los Angeles," said Dr. Irina Irvine, restoration ecologist for Santa Monica Mountains National Recreation Area. "What's more intriguing about this study is learning how high nitrogen levels affect native vegetation and what that might mean for fire risk in such a fire-prone region."

The preliminary results are from the first year of a three-year study undertaken by Irvine, UC Riverside's Dr. Edith B. Allen and the U.S. Forest Service's Dr. Andrzej Bytnerowicz and Dr. Mark Fenn.

Researchers measured atmospheric nitrogen deposition levels at 10 sites throughout the Santa Monica Mountains and found significantly higher pollution levels in the eastern end (See map) . At the two sites with the best air quality, they added various levels of nitrogen into experimental plots of coastal sage scrub to simulate pollution levels found throughout the mountains. 

Higher levels of nitrogen led to a decline in native shrub seedlings and an increase in nonnative grasses. Other studies in Australia and California have demonstrated a link between nonnative grasses, also known as "flashy fuels," and larger and more frequent wildfires.

Funded by the National Park Service's Air Resources Division, the $100,000 study will help scientists better determine the "critical load" when vegetation shifts, causing alterations to the structure and functionality of ecosystems. Coastal sage scrub once covered much of coastal California and is now an endangered habitat type, primarily due to development. 

Generally attributed to vehicle emissions in the Santa Monica Mountains, nitrogen deposition is the air pollution from industry, agriculture and transportation that settles out of the atmosphere and onto the earth's surface.

Santa Monica Mountains National Recreation Area (SMMNRA)is the largest urban national park in the country, encompassing more than 150,000 acres of mountains and coastline in Ventura and Los Angeles counties. It comprises a seamless network of local, state and federal parks interwoven with private lands and communities. As one of only five Mediterranean ecosystems in the world, SMMNRA preserves the rich biological diversity of more than 450 animal species and 26 distinct plant communities. 

Visit: http://www.nps.gov/samo/index.htm

UC Riverside's Plant and Botany Sciences Department conducts cutting-edge research in plant biology to advance fundamental scientific knowledge and solve critical issues for the state of California, and educates and trains graduate and undergraduate students to become science professionals and informed global citizens. 

Visit: http://plantbiology.ucr.edu 

USFS Pacific Southwest Research Station develops and communicates science needed to sustain forest ecosystems and other benefits to society. Headquartered in Albany, Calif., it has research facilities in California, Hawaii and the U.S.–affiliated Pacific Islands. For more information,  

(source)

Warning: You should know the California Chaparral Institute's owner, Richard Halsey, has dismissed this research as of little account & flawed. Whatever! 😒

Photo: Joe Decruyenaere

Adenostoma sparsifolium and Ceanothus megacarpus,
upper Stunt Canyon, Santa Monica Mountains

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(Update: Jan 17, 2014)
The above article is fascinating and certainly revealing of what is happening out there in the Natural World not only at present, but has actually been going on for the last several decades. It is popular today to blame everything wrong with the Earth as global warming. Global Warming has always been a lousy title for describing what is going wrong with the Earth, especially climate. But there are so many natural components to ecosystem breakdown that very few of the Experts seem capable of putting all the pieces together. Yes there are these CO2s exacerbating the problems with regard climate, but there is so very much more. Almost all of Earth's old growth vegetation systems are being depleted and if you have read much within these "Earth Internet" archives, you've come to realize from the references provided, along with my personal observation and practical application (without practical application, any knowledge or understanding is completely useless), that science for decades has known about the major role playing that healthy vegetation (& not just this love affair with Rainforests love, not that there is anything wrong with rainforests mind you) play in global cloud formation, seasonal rainfall and overall global climate moderation. But vegetation breakdown doesn't simply happen by means of climate change. From the above article, clearly it is a mechanisms issue. If there is a breakdown in the adjoining plant components like beneficial fungi or bacteria, then the bad health and eventual death of vegetation won't need to experience drought for total shutdown. 

There have been other articles in the past, some decades ago alluding to this potential problem in the future. But guess what ? The future has arrived and with a vengeance. For example this paper (here) by Duke University in 1993, which suggested that, "Increased nutrient availability reduces vesicular-arbuscular mycorrhizal (VAM) associations with plants". Of course complete understanding then was not what it is now, but at least they were giving this as a possible future issue. But then there was another paper in 2003 by the Ecological Society of America, who has a commitment to soil ecology and rebuilding ecosystems. They had a great piece on this same issue, which clearly had gotten worse since the studies since 1993, and there was a great illustration inside this piece which unfortunately I cannot link to anywhere, but I've substituted one below from another site for learning purposes only. 

Illustration - semanticscholar.org

The subject in the paper was, (nitrogen enrichment alters mycorrhizal allocation at five mesic to semiarid grasslands) and the illustration in that paper as you scroll down at page #1897 had an animation of two grassland plants, on the left with normal healthy microbial soil and on the right, soil with nutrient enrichment of nitrogen. The left side had far more roots and mycorrhizal networking associated with the plant, the one on the right dramatically less root and fungal colonization. Now look above left at the photos. This is a Pine seedling colonized on the right with ecto-mycorrhizae,  Pisolithus tintorius and the photo on the left has been digitally altered to remove the fungi in the picture and reveal the lack of enhanced mechanism which the the fungus offers the plant for vastly improved growth and survival. The nitrogen nutrient enriched soil will destroy this mycorrhizal colonization of the plant as represented by the picture on the left. This destruction is actually a removal of a major extensive network plumbing network which is extremely efficient at providing 200% more water and nutrients the plant would otherwise not receive on it's own. You can test this out yourself in your own healthy organically maintained landscape, if you even have one, by changing your maintenance regime to Scotts Miracle Gro or any other Industrial Science produced product sold at your local hardware. But rather than do this, take not only my word, but the studies done on this. Over decades this nitrogen(& other nutrients) has built up in our wildland soils to the point of where concentration levels have increase so much, we are now seeing the unhealthy effects of most all vegetation foliage. This is especially true in the western USA where dead or dying ecosystems are now not only a horrible habitat for wildlife, but even more of an increased wildfire hazard. It also offers clues as to why there would also naturally follow the present  breakdown in weather creation and maintenance mechanisms around the Earth.

(Further Update February 16, 2014)

University of Minnesota study finds, Fertilization destabilizes global grassland ecosystems

(earlier July 3, 2013) Study reports on declines in ecosystem productivity fueled by nitrogen-induced species loss

University of Nebraska - Lincoln "Worldwide study finds that fertilizer destabilizes grasslands"

 Nutrient Network: A Global Research Cooperative

Further research is also being conducted on the possible negative effects of Biocrustal degradation in deserts as a result of nitrogen nutrient enrichment. Here is an advert looking for research participants for a project running from Spring of 2014 to 2015 at the University of Las Vegas. This was originally posted at my attention from Mathew Bowker's site. Clearly, no living ecosystem is immune from the effects of nutrient enrichment where it doesn't belong.

Biological Soil Crusts: The Role of Trampling, Climate Change and Nitrogen Deposition in Affecting Community Species Composition

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(Further Update February 19, 2014)

Another interesting article on a little plant called Duck Weed in ponds or lakes. Often times demonized for taking over and becoming weedy. Over fertilization of waterways or otherwise known as Eutrophication, is actually what is responsible for this excessive growth of Duckweed. Much like the pea soup green of an algal infested pond, it's the human overuse of fertilizers or other nutrient enriched runoff from streets during rainstorms which fuels the population explosion other organisms. It is not the fault of the organisms, but rather once again human error. Needless to say, this was also an enlightening article. It reveals how duckweed has been  been used to clean up contaminated waters and as a source to produce pharmaceuticals. Now as a source to create biofuels. Still, it's human cause imbalances in nature which trigger the imbalances.

Pond-dwelling powerhouse's genome points to its biofuel potential

Now, continuing on with an even later article from the same Ecological Society of America recently in 2011 entitled: Using Air Pollution Thresholds To Protect And Restore Ecosystem Health  which deals with the same issues of air pollutants and their effects on the environment as a result of their prolonged accumulation over time in the soils. The USFS also did a reprint of it (here). It's this accumulation factor over time that I have also wondered about which may further make invasive weeds & other non-native grasses gradually more and more successful over the past decades. These were most always bottomland dwellers as a historic rule. They thrived where traditionally an accumulation of nutrients from much higher elevations over time build up in mountain meadows and/or lower elevation valley floodplains. They thrive in a nutrient higher bacterial setting, not a nutrient poor mycorrhizal setting on mountain tops. However nutrient poor such a setting is on mountains, it nevertheless suits the chaparral plant community perfectly. Clearly there is more we need to know about how this system works so successfully. When I was a kid growing up in El Cajon and if Rattlesnake Mountain or any other wild region did catch fire, the following Spring after Winter rains, it was mostly native wildflowers smothering the landscape, many of which are nitrogen fixers as part of Nature's soil rehabilitation mechanism which would appear in complete cover, only to gradually disappear or rather become smaller and more inconspicuous as chaparral took over in the gradual natural progression or plant succession. Take a look at the picture below posted on David Senesac's blog where he photos still pristine areas after fire in western Riverside County CA.

Photo by David Senesac

Spring 2008 Wildflower Trip Chronicles 
from Lake Elsinore to Coyote Canyon

Wikipedia (Deerweed)

The above picture of a mass flower scene with multiple species of wildflowers was typical of what I saw growing up as a kid in and around El Cajon. The following year after such beautiful displays however, these wildfire annuals would give way to more longer lived perennials like Deerweed (Lotus scoparius) and White Sage (Salvia apiana) which were always the two dominant plants to rule over the mountainous landscape prior to Cal-Buckwheat & Sagebrush asserting their dominance a decade later. Like the various species of native California wildflowers, the White Sage and Deerweed would always remain present, but in smaller forms in between the dominant Sagescrub plants. Still, decades after the 1960s, you could sense things changing if you lived in and around this area and hiked it's pathways yearly. Something more than human mechanical damage is allowing these plants to succeed on the slopes where they never historically could before.

Photo Mine (2013 Rattlesnake Mountain, El Cajon California)

Invasive non-native African bunch grasses normally used by Cal-Trans and seen along Interstate Freeways in Southern California for supposedly holding banks together and preventing erosion. This view is on Rattlesnake Mountain in El Cajon and was taken in Spring of 2013 prior to me being threatened by surrounding neighbourhood Sky  Ranch Housing Community residents for being on protected conservation land. These were the same neighbourhood community people that chained sawed the remaining 30 foot Torrey Pines behind this shot because they said the were an invasive species and were known to cause brushfires. The trees had their first crop of cones that previous year and the folks insisted they would spread. They did indeed reseed with some seedling under California Buckwheat with help of ScrubJays, but most of the ones I saw did not make it through these dry present drought years. Even still, what a success story. Yeah, what a crime that would have been to see such plants as Torrey Pines succeed. You should however take note in the scene above and on the other side of those non-native African Bunch Grasses at the top of the picture are several solid acres of invading Mediterranean Black Mustard and Yellow Star Starthistle which previously never existed up there before. Especially prior to Star Ranch Development. While these plants (with the exception of Starthistle) were in existence back in the 1960s on the El Cajon Valley floor, they were non-existent in the higher elevations above and never did make any headway, even after fire. Now the soil dynamics have clearly changed, becoming somehow enriched and which proves that something else is allowing them to be successful beyond the usual human soil disturbance. Clearly nutrient enrichment by means of pollution may well be the culprit, even if it comes in the form of rainfall with a nutrient content even if slight. Over decades, concentration buildup takes it's toll.

There was something else the article mentioned, that I had briefly noticed and thought about previously, but dismissed it as of little consequence. This is the increase in Mistletoe and such beneficial organisms such as Lichens on chaparral plants. As previously written about before in this blog citing studies, Mistletoe can be actually beneficial, despite it's being unfairly demonization by the so-called experts. The above referenced article at the top however, also mentioned this about Lichens:

“Fertility sounds like a good thing,” Driscoll said, “But over-fertilization can cause the sudden overgrowth of some plants, algae or bacteria at the expense of other species.” The characteristic algal blooms that follow sewage releases or agricultural runoff are caused by the influx of nutrients. Overgrowth of plant life in estuaries can push oxygen levels so low that fish die. 

Tree-inhabiting lichens and tiny, distinctive, single-celled algae species called diatoms are very sensitive to nitrogen compounds, and so changes in their relative abundance make good early warning signs for larger ecosystem changes, say the authors. Atmospheric ammonia is a particular problem because it is not regulated.

Image: Rick Halsey - Chaparral Institute

Now the term here being used is Tree-inhabiting Lichens. These Lichens have been present everywhere in chaparral and other plant communities since before Trees and Shrubs were in existence and they are actually foundational to ecosystem recovery and plant succession. There is an ignorant viewpoint of lichens as tree-inhibiting or destroying and this was parroted around the middle of last year after the 2013 Mountain Fire near Idyllwild California. The resident Biologist referring to chaparral with an abundance of Lichens and Mosses labeled the community as old and decadent, in other words in need of burning by fire. What interested me in the abundance of the presence of Lichens is not that they kill trees and shrubs, but that under stressful environmental or other unhealthful conditions they will be more abundant. Lichens are not tree or chaparral killers, but their increased presence may mean that there quite possibly may be a break down in the immune system health of these plants, whose natural defenses have allowed Lichens to increase. Perhaps drought or as is the case here, increased nitrogen increase. I have noticed increase in Lichens on Chaparral, but have paid it no mind in the past. Now I myself will rethink the observation the next time I'm out in the field. It may well be that these lichens could be viewed upon as bioindicators that the nitrogen cycle is cascading to the extent that the ecosystem is in collapse. Any research references or Foresters will tell you that lichens do not harm trees, and that typically, they grow so slowly as to be imperceptible. Here are some relevant quotes from that US Forest Service piece about increased presence of Lichen being an indicator of something else going wrong, aside from increased nitrogen's effect on invasive weeds:

US Forestry: "Setting Limits: Using Air Pollution Thresholds to Protect and Restore U.S. Ecosystems"

"Biodiversity of plant communities is sensitive to N added by air pollution. Nitrogen-loving species are often favored and increase in prominence as ecosystem nitrogen availability increases. Forests and woodlands in many regions of the world show large changes in epiphytic lichen communities in response to chronic atmospheric nitrogen deposition. These lichen community impacts occur at nitrogen pollution thresholds as low as 3-6 kg/ha/yr."

The photo below here is illustrative of massive amounts of excessive Lichen growth on Chaparral in the eastern Anza area and especially Burn Valley. This area also has one of the worst problems of over colonization of Mistletoe which also is strangling what life is left in these shrubs. But it is hardly the sole reason for the major decline in chaparral health. Drought in combination with nutrient enrichment no doubt favour such a decrease of plant health and increased growth activity of Lichens and Mistletoe. But for some years to the present, this region was also my best mycorrhizal truffle collection area, but as time went on, sharp declines in truffle formation and availability became apparent. Along with the sharp decline in truffle, I also saw massive die offs in Coulter & Jeffrey Pines at these same exact locations. It is interesting that lack of truffle presence was followed by sudden die offs of trees. This first happened in and around 1990, but was not limited to eastern Anza. Garner Valley was effected in mass die off as was the whole of eastern Palomar Mount and over in Arizona when we would visit Prescott National Forest in and around the city of Prescott. Literally 10s of 1000s of trees were dying or dead. It was a sad time, but certainly a memorable one as everyone was talking about it back then. Of course the Bark Beetle gets the blame, but as with Lichen increases there is clearly something else going on which is unseen to the naked eye.

photo by Vandekar

Chaparral being swallowed by excessive infection of Lichens

"Lichen community change from oligotrophic [Oligotrophs are characterized by slow growth, low rates of metabolism, and generally low population density] and to eutrophic species dominance" [fast-growing, nutrient enriched like this one, bigger than the branch it's on!]

From Table 1., Nitrogen Deposition: US Forest Service

"Adding nitrogen to forests whose growth is typically limited by its availability may appear desirable, possibly increasing forest growth and timber production, but it can also have adverse effects such as increased soil acidification, biodiversity impacts, predisposition to insect infestations, and effects on beneficial root fungi called mycorrhizae. As atmospheric nitrogen deposition onto forests and other ecosystems increases, the enhanced availability of nitrogen can lead to chemical and biological changes collectively called 'nitrogen saturation.' As nitrogen deposition from air pollution accumulates in an ecosystem, a progression of effects can occur as levels of biologically available nitrogen increase."

It would be interesting for those who are avid outdoors people and love hiking to take special note of areas with increased Lichen colonizations which were never observed before and take ongoing note of any increase and death of trees or shrubs. This of course would not be the fault or result of increased Lichen grows as it would indicate something unbalanced and going on terribly wrong within the soil itself which is actually creating the so-called decadence or branch die-off as many mistakenly describe Chaparral. It has been well known for some time that in the landscape and garden, the excessive use of high nitrogen fertilizers will actually harm beneficial soil organisms and actually attract pests to your plants. This may actually be the cause of so much ecosystem decline around the Earth, aside from the usual suspects, and may not have been noticed previously until present high levels of contaminants have reached this present critical concentration levels everywhere. There truly is far more than mere global warming and CO2s effecting our natural world. In any event, experimenting with various fertilizers in the landscape may just illustrate this point more rapidly. Again, pests get a bad rap, but only because hidden things are out of balance. 

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Update: April 8, 2015

"Nitrogen deposition reduces Swiss plant diversity"

"High human atmospheric nitrogen emissions lead to a reduction of plant diversity. Researchers at the University of Basel analyzed plots all over Switzerland and report that the plant diversity has decreased in landscapes with high nitrogen deposition. The journal Royal Society Open Science has published their results."

(Source: University of Basel)

"Nitrogen deposition poses a threat to the diversity of Europe's forest vegetation"

"Unless nitrogen emissions are curbed, the diversity of plant communities in Europe's forests will decrease. Atmospheric nitrogen deposition has already changed the number and richness of forest floor vegetation species in European forests over the last 20–30 years. In particular, the coverage of plant species adapted to nutrient-poor conditions has reduced. However, levels of nitrogen deposition in Finnish forests remain small compared to Southern and Central Europe."

(Source: Finnish Environment Institute SYKE)

Even seemingly isolated and pristine areas like Desert ecosystems which seem far removed from polluted environments are in trouble. Update 2018

Image: Saguaro National Park

"Healthy ecosystems can naturally buffer a certain amount of pollution, but as nitrogen and sulfur accumulate, a threshold is passed where the ecosystem is harmed. “Critical load” is a term used to describe the amount of pollution above which harmful changes in sensitive ecosystems occur (Porter 2005). Nitrogen deposition exceeds the critical load for one or more park ecosystems (NPS ARD 2018)." 

Park Air Profiles - Saguaro National Park

Anyone care to take a guess what the nitrogen and other contaminant concentrations levels are in and around the wild landscape we call Asia ??? What effect does this have on those native plants and their symbiotic companions ??? Oh wait, too late. A Japanese Scientist has already answered this here in the New York Times:

Scientist Says Pollution From China Is Killing a Japanese Island’s Trees 

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Further Educational Reading References

http://www.fs.fed.us/psw/publications/fenn/psw_2011_fenn002.pdf