Understanding just how invasive Tamarisk trees suck the life out of native Fremont Cottonwood ecosystem, may help us in rebuilding all other various types of ecosystems successfully without relapse
|Mr Doug Fir's fake Facebook status account created with www.statusclone.com|
In almost every discussion I've ever had about ecosystem &/or habitat restoration with various people and groups, the methods &/or techniques discussed have always been (removal = mechanical & toxic chemicals) followed by (solution = selected native nursery grown plants plugged into ground vacated by exotics) and viola it's restored. But of course it's not that easy as can be testified by the fact that they have to continue with numerous follow-up restorations until they feel they have attained a measure of success. Those continued follow-ups are the exact result of almost no one considering inoculating the soil around the plants with a healthy blend of plant specific mycorrhizal inoculum. When I bring this subject up because I usually always get those who aalways insist, "Oh you don't need to do that, because all those good fungal spores are just everywhere in the air." Yeah, maybe way back when ecosystems were more untouched, but not now in our modern times. I've written previously how many of my many years of favourite truffle collection spots have ceased to produce and mainly it came a few years prior to their host's dying. Why did this happen ? I have no idea. But there are a plethora of things scientists in general do not understand despite their putting happy faces stamped on their proposed solutions.
|Image - Roeselien Raimond|
"The answer my friend
When you look at and deeply ponder any type of weedy infestation within a former healthy native ecosystem which is almost exclusively exotic invasives, it's a pretty good probability that those beneficial fungal mycorrhizal networks most likely don't exist in that soil profile anymore. That's logical since the fungi need a viable specific host in order to actually keep alive and the annual invasive weeds (Ruderals or exotic shrubs & trees) have employed a phytochemical tool coupled with continuous human disturbance (Agriculture, Wildfire, etc), we can pretty much assume a bacterial soil profile has taken it's place. The conventional theory is, disking & blitzing the weed infested area in question with Roundup, then following up with planting a native seed blend version of "Meadow in a Can" isn't going to cut it. You have to restore the underground mycorrhizal soil profile with inoculated perennial native plants like Lupines, Poppies, etc for the restoration to succeed. Same is true with restoring native trees & shrubs. Logically, if we observe above ground failure of an entire ecosystem, it's a pretty good bet that something may not be functioning normally under the ground on a microscopic level. In my own experience with planting various pine specimens I collected for my own 3+ acres up in Anza, California, I'd often find that nearby healthy looking scrub oaks really came to life with heavier foliage and larger leaves the following year after planting my inoculated pines with Pisolithus tinctorius. The fungal system which colonized the pines moved underground, also formed a bond with the scrub oaks and truffles appeared in the Spring just outside of the oak's dripline area. What puzzled me was why this specific fungi not been already present before when large tree areas on the other side of Hamilton Canyon always had them ? Apparently we cannot count on the air being our friend. Take this picture below. A recent discussion on "California Invasive Plant's" Facebook page motivated me to address this subject and finish this post that I originally started as a draft some months back.
|Image - R.R. Alexander in 2010|
California Poppies - Diamond Valley Reservoir south of Hemet
|Image - Jeff Schalau via slco.org|
Reduced mycorrhizal responsiveness leads to increased competitive tolerance in an invasive exotic plantAfter acknowledging and providing info on how Star Thistle grows unsuccessfully where soils are Vascular Arbuscular Mycorrhizal (VAM) coupled with the presence of perennial bunchgrass Stipa pulchra, take note in the later part of this sentence in the first bullet point under the Summary:
" . . , although this remains poorly studied."Now notice this other study on how invasive Black Mustard (Brassica nigra) has been shown to change soil microbial dynamics by suppressing mycorrhizal fungi and changing the underground system to a bacterial one and take a look at this last sentence:
"There is a need for additional research for more informed agricultural decisions over large spatial scales to avoid potential negative impacts of members of the Brassicaceae on native plant communities."Here is yet another example study done on a different European invasive called Garlic Mustard (Alliaria petiolata) which has invaded North American forests suppressing mycorrhizal networks which have effect all hardwood seedlings.
"Nevertheless, experimental data on species-level impacts of exotic plants are still limited."
"Further research in these directions is needed to better understand the effects of this invader on natural ecosystems and the mechanisms involved."Finally, moving away from non-mycorrhizal ruderal weeds and looking at ability of an aggressive non-native tree, Tamarisk, to change underground soil biological mechanisms, here is the research on how invasive Tamarisks suppress mycorrhizal connections for Freemont Cottonwoods along aquatic habitats. Notice some of the same wording of where little is known and more study on the subject must be researched.
Disrupting mycorrhizal mutualisms: a potential mechanism by which exotic tamarisk outcompetes native cottonwoods
" . . . yet our understanding of this mechanism's role in exotic species invasion is still in its infancy."This next link from the United Nations agricultural department get's to the heart of the matter in utilizing Endo & Ecto Mycorrhizal fungi in restoration projects regarding cottonwoods & willows with regards riparian habitats high in soil salinity, especially where massive invasive of Tamarisks have exacerbated the problem to higher salinity levels. They recommended two types of mycorrhizal fungi, Hebeloma crustuliniforme and Paxillus involutus, which have the best qualities of eliminating the negative effects of high salinity in soil. But once again, take special note of the disclaimer they have on more research needed.
" Although the current data are very fragmentary, they suggest that inclusion of mycorrhizal management in reclamation strategies of salinity affected land may increase the success of such measures. It is obvious that more information is needed on the interaction and possible ameliorative influence of mycorrhizae for poplar under salt stress."
|Photo - Michael Wood & MykoWeb|
Again, in almost every single study I've ever read and or researched, you'll notice in the concluding comments where they admit how little effort has been put forth into investigation of mycorrhizal fungal research as much as Scientists has been obsessed with putting more focussed resources into studying those negative microbial elements such as pathogenic fungi Fusarium oxysporum which they admit has been researched for over 100 years. But why ??? Because there is far more money in the continual fight against pathogens with science-based synthetic toxins year after year, than creating an ecological equilibrium which is perpetually sustainable. Any Tamarisk eradication project I've ever seen is mostly about mere removal. That's great, but you need to replace with natives which provide an ongoing mycorrhizal (ecto & endo) soil system. Like fungal spores, native riparian tree seeds won't magically blow in on the next wind and heal the system. The system doesn't work as it once did. The misuse and abuse of various science disciplines have reversed engineered ecosystems so badly, that many need a hands on approach when engaging in restoration work. Otherwise the Tamarisk comes back which as I've stated before is job security for some people with a vested interest in keeping the status quo. Clearly from the above links, you can see that many in the Science biz have done the research and revealed how nature really works. But unfortunately that's not the type or kind of Science that rules academia or big business. Why ??? Ever read this quote before:
“It is difficult to get a man to understand something when his salary depends upon his not understanding it.”
|Image - Go.Nature,com|
Well, they can make the determination to do research
& inform mankind about how Nature really works.
Or yield to the demands of your Corporate employers.
Like the Hebeloma crustuliniforme mycorrhizal fungi referenced in the Cottonwood vrs Tamarisk research paper, another mycorrhizae, the Paxillus involutus, also forms ectomycorrhizal relationships with a broad range of riparian tree species and not just cottonwoods. According to that research, if there are healthy populations of these ectomycorrhizal fungi in present within Fremont Cottonwood groves, the Tamarisk apparently has a tougher time dominating. There are clearly multiple benefits from these symbiosis as the fungul partners reduces their host's intake of heavy metals, high soil salinity and actually increase their host's resistance to the pathogen fungus like Fusarium oxysporum. These and other important varieties fungi and beneficial bacteria need to be employed within the blueprints of any riparian restoration planning.
"Most areas were cut by hand, thereby selectively cutting out the tamarisk while leaving the native shrubs unharmed. Only a 7.5 acre (3 ha) section that was heavily infested (> 95%) was cleared using a bulldozer." "In the 7.5 acres (3 ha) that was bulldozed, natives established much more slowly than in the hand-cleared areas."
"In the 7.5 acres (3 ha) that was bulldozed, natives established much more slowly than in the hand-cleared areas."This quote from the article is fascinating. So areas cleared in a large scale mechanized way by bulldozers in the heavier infested area with large trees provided a clean slate upon which to rebuild and restore native vegetation, but it recovered more slowly compared to other area cleared by hand. An area cleared by hand would be more carefully methodical and surgical in it's approach to not disturb other native shrubs. This faster recovery of the later site makes sense because no matter how unseen mycorrhizal networks are to the naked human eye, they never the less do exist under the ground. This same phenomena of hand removal vrs mechanized on this project was also reported and commented upon by the Angeles Chapter of the Sierra Club. But beyond the acknowledgement of the outcome (mechanized removal vrs hand tool removal), not one of the Authors commented on improving techniques for restoration through biomimicry by utilizing a surgical proceedure of hand tool clearing as opposed to using big machinery and stripping eveything of the surface of the land. Clearly mechanical stripping completely destroys the mycorrhizal grid underground and it takes plants much longer to establish themselves. It was also interesting about the revitalized Spring reappearing mere hours after Tamarisk removal.
"A Spring Reflows"
"Remarkably, the spring in Thousand Palms Canyon began flowing again for the first time in years just hours after the first large tamarisk cutting effort there. Revegetation of all the cleared areas occurred quickly and inexpensively. Seeds were collected from nearby shrubs and trees and strewn onto the cleared areas after the tamarisk was removed. In the area that was bulldozed, natives established much more slowly than in the hand-cleared areas. Native inkweed, saltbush, quailbush, and alkali goldenbush are now growing in dry areas, and the desert fan palms, willows, cottonwoods, and common reed are well-established in wet areas."
Some major roadblocks to Tamarisk eradication and native Riparian plant restoration
|Photo - U.S. Geological Survey|
|Robert Browman/Albuquerque Journal (2013)|
|Image - Cornell Lab|
|Jay Calderon The Desert Sun|
Lawsuit Filed to Save Endangered Southwestern Songbird From Habitat Destruction Caused by Invasive Beetles
Some references on successful restoration and other observationsOne of the most outstanding anomalies from removal to me was the response of the long dried up Spring at the 1000 Palms Canyon Oasis reappearing and flowing on the surface again just mere hours after Tamarisk removal. There has been some intellectual criticism by those wanting the Tamarisk to be left alone arguing that native riparian vegetation also creates evapotranspiration just like Tamarisk. So ??? Nobody would dispute that, but clearly the Tamarisks do suck down more water because the native vegetation which has replaced them still allows these springs to flow freely. It's a given that any riparian plant ecosystem with trees would evapotranspirate, but clearly not as bad as a massive Tamarisk infestation. In this age of dwindling fresh water supplies, why would hydrologists everywhere not be looking at this ? Remember what was observed by the 1000 Palms Oasis Tamarisk removal site ? Springs flowed again within hours of removal. The native vegetaton never suppressed the Spring and now even the various native critters can all benefit as a result of surface waterflow. Major win win all around for everyone and everything. Where have Roger C. Bales (UC Merced) & Michael Goulden (UC Irvine) been all this time when we really needed them ??? 🙄
|Image .Gifloop 2011|
"Remarkably, the spring in Thousand Palms Canyon began flowing again for the first time in years just hours after the first large tamarisk cutting effort there."Okay, the photo GIF above is not the actual 1000 Palms Canyon Oasis spring referenced in those articles. I merely used it here for an illustrative purpose. Clearly however, Tamarisk do use massive amounts of water when compared to other native vegetation as evidenced by this restoration program's outcome. That's not say riparian trees don't use water, they do. But their effect is not as dramatic on the ecosystem. Below is a link to the NASA website's Multimedia Invasive Species page where they use various animations to illustrate this tree's aggressive ability by means of a deepermassive root infrstructure and phytochemical warefare to outcompete the natives and eventually creating an almost entirely Tamarisk monoculture. No room for left for other plant biodiversity. Apparently this goes totally unnoticed by the Center of Biological Diversity who now wish to coddle and cuddle this plant.
|Credit . National Park Service|
"Experts estimate that one large tamarisk plant has the potential to absorb up to 200 gallons of water per day – that’s twice the amount the average person uses in the same timeframe."
Credit: NASAWow, 200 gallons of water per day ? Well, let's compare that with a couple of native plants which are often heavily demonized in Texas by the Cattlemen's Association. These would be Mesquite and Ashe Juniper. Both of these shrubby trees are natives, not invasives, but labeled invasive noxious weeds by those with a vested interest in something that provides a living like grasslands. In this case grasslands are the desired plant community.
|Arizona Daily Independent|
"Mesquite trees, for example, have lateral root systems extending up to 50 feet from the tree, greatly increasing their ability to absorb available moisture. A mesquite trees eight- to 12-feet tall can consume 20 gallons of water per day; ten such mesquites can use as much water in one day as one Texan does."Interesting. So compared to a Tamarisk tree, a Mesquite tree uses only 20 gallons of water per day as compared to 200 gallons per day. And apparently 10 Mesquite trees suck 200 gallons per day just like your average Texan. Here is another demonized tree, the Ashe Juniper. Like the Mesquite, it too is a native to Texas.
"A large juniper can consume 40 gallons of water per day during the midsummer with moderate soil moisture. Six junipers, then, use about as much as one Texan does daily."Interesting again, but of course this tree is said to use 40 gallons of water per day. It takes six of them to equal one Texan whom like the Tamarisk consumes 200 gallons per day. Seriously though, I would have guessed that the Juniper would be using less water than the mesquite tree. But there is an interesting reason as to why these two trees are being demonized below. Cattle Ranchers only want grasslands for their personal business interests to thrive. Take a look below from the same website where this info came from and their reasoning.
|Image - Cedar Eaters of Texas|
Junipers have a deep root structure and a dense mat of fibrous roots near the soil surface that allow them to absorb moisture from the driest of soils, to the detriment of grasses, creeks and springs. Mesquite and cedar have no ability to conserve water and will throw off what ever amounts they absorb. Other trees conserve and limit their water usage during the heat of the day, controlling their water loss or output.Now the only thing I'm walking away with here in the reading this article is that probably both Tamarisk and Texans are what really need to be eradicated. Okay I'm kidding. Well, at least on the part about Texans😉. Again, the link above under the NASA photo of the Tamarisk tree along with it's critique on Tamarisk water usage, also provides good animation of just how aggressive the evapotranspiration of Tamarisk is when compared to a Fremont Cottonwood. There are those that will dispute the 200 gallon of water per day figure. For example the other government site, US Geological Survey site disputes the higher figure. Ultimately the scientists behind the research (one way or another) are motivated by personal bias, compensation by those funding their study and they are also prone to mistakes. The Tamarisk removal and restoration of native plants at the 1000 Palms Canyon site in Coachella Valley is a prime example of what is more likely true as a result of the resurfacing of the stream within hours when water sucking Tamarisk was removed. The key here is figuring how much was used can be easily assessed by the fact the water resurfaced within hours. Had it been many days or a week, then maybe not. This animation below illustrates what happens when the wrong vegetation exists along a river or creek bed and much further away inland from the surface waters.
|(Illustrations from Alley and others, 1999)|
Diagrams of groundwater movement in relation to streamflow
If you notice the top illustration we see a normal surface flow with the native Fremont Cottonwoods, Willows and Mesquite. Logically the Cottonwoods & Willows would be closest to the water course, while Mesquite would form large Bosque woodlands much further away as a result of a very high water table. No ill effects of dense Mesquite thickets would be experienced if the 20 gallon per day usage per tree were true. Also by means of the capillary action of water from the higher water table far away from the river or stream and actually moving up higher than into the banks and foothills in the floodplain. This would be further enhanced by the hydraulic lift and redistribution of deep subsoil moisture towards those higher surfaces by the native trees and shrubs. I have yet to find any similar phenomena with Tamarisk in any literature. On the other hand if the thickets were invaded by Tamarisk with a higher need for water, then the seond illustration would go into effect with a lowering of the below ground water table. At this point the surface water is not dependent so much on volume of water from the water table as it is forced to give it's reserves from the upstream intake down into the water table causing the surface flow to shrink. In the third picture the stream is totally separated from the water table and in our desert scenario it would be bone dry as the water table would be maybe 3 meters or 10' below the floodplain with river bed surface being dry in a desert scenario. To further counter the new Tamarisk love affair by researchers who now say it's not such a bad guy after all when it comes to being thirsty, here is a video below of how the huge extensive infrastructure of Tamarisk Windbreaks are maintained in the Coachella Valley along I-15 & the Railroad right-of-ways.
Why and how Windbreaks are needed and maintained with massive water flooding in the Coachella Valley
|Image - CS Trains.com|
Tamarisk Windbreaks along ATSF track right-of-way in
the Coachella Valley between I-10 and Palm springs
I can verify for a fact that there is a massive water wasting by the railroad in irrigating these Tamarisk windbreaks. In actual fact when I was on the ground down by those tracks in the earlt 1980s and walked the right-of-way, I saw those heavy duty irrigation pipes just pouring out water from 2" openings in between each tree. There was no drip system. I further verified this wasteful massive need for water from the Desert Water Agency's, Ronald Baetz, who said massive amounts of water were required for the Tamarisk to heal itself from the constant sand blasting it receives from high intensity winds through Windy Point. He insisted it was the only plant that could rapidly regenerate itself, but I had seen the same thing from various native dune Mesquites out there. It's true, the winds are insane and sands storms are constant here and need for permanent windbreaks can be seen from the picture of this railroad track right of way in the Namibia desert in Africa. But perhaps building a permanent large berm structure from local natural materials (sand, rock, etc) and heavily planting this structure with multiple diverse native desert trees and shrubs is the way to go. I previously wrote about this with regards UCSD's old Mesquite Dune Project.
Finally in ConclusionThe studies on how Tamarisk changes soil chemistry and disrupts the mycorrhizal mutualism between both endo & ecto mycorrhizae and Fremont Cottonwood (not to mention how all other non-mycorrhizal invasive plants accomplish this) illustrates how important it is for restoration groups to inoculate at time of planting. In a year's time a sterilized riparian habitat could be dense enough to crowd out and kill Tamarisk seedlings which hate shade.
|Image - Stillwater Sciences (2006)|
In many extreme cases, total stripping of landscape may be necessary depending on how heavily infested a site is with multiple invasive species. Admittedly, in such cases the mycorrhizal grid will be totally destroyed. Same with heavy ruderal weed thatch needing to be mowed and possibly deep plowed under before planting perennial native wildflowers and grasses back into the landscape. Generous mycorrhizal inoculation will be necessary for the restoration to succeed. Think of the underground and take necessary steps, it'll be worth it. The site above with bare soil is also the same location in the photo below after two years with cottonwood trees. Remember, Fremont Cottonwood will do best with a couple of good species of ectomycorrhizal fungi. It's imperative to do everything right from the start, otherwise you'll most likely need more major followups. Weeding might be necessary the first year, but shouldn't be that bad. Heavy mulch should also be applied. Remember that a dense canopy of thick riparian trees is imperative to shade out any newer Tamarisk seedlings. You can thin out later, remember that this is what nature would naturally do with massive amounts of competition after major flooding during the rainy season.
Stillwater: Bradford Island Riparian and Wetland Restoration
|Image - River Partners|
|Riparian Invasion Research Lab (RIVRLAB)|
|photo is mine - El Cajon 2007|
Two years old California Sycamores, planted in 2005 and all
six trees from one gallon containers. All were six inches high
Ever see a massive boulder strewn dry expansive floodplain in SoCal up in San Bernadino or riverside county and wonder how a giant specimen of water loving tree like California Sycamore or Fremont Cottonwood got there when they are a mile or more from a main river or creek channel ? Me too. A lot has to do with wetter rainy season patterns in facilitating establishment and root infrastructure development to the water table. Amazingly this can be replicated in restoration work and urban landscapes where water is rare, precious and expensive. That's what I did above with these six inch high California Sycamore seedings which were planted in September 2005 and photographed above in June 2007. Let's take a real quick short lesson here, shall we ??? 😁😉
|Sycamore-lined Alameda Creek @ Sunol Regional Wilderness|
Most of us in dry areas of the Southwestern United States picture the water loving Sycamore in a habitat where was can be permanently seen when visited or even if streambed is dry, it's a perennial stream and Sycamores generally line it's banks. But this is not the only place you'll find the picturesque California or even Arizona Sycamore.
|Image taken from Google Earth|
Here is a photo taken from Google Earth along the Interstate 215 freeway in Devore California. This is a normal dry hot and often times exposed windy area north of San Bernadino. The grographical habitat is an expansive alluvial floodplain with temps in summer almost always over 110+ Fahrenheit or 40 celsius. Most of the vegtation type is low growing sage scrub or chaparral and grasses with annual wildflowers. But did you notice the small sycamore right smack in the middle of all this ??? Have you ever wondered, how did such a water loving tree get here and how does it still survive now ???
|Image - San Franciscon Estuary Institute|
Further question is how does such a sapling eventually turn into a giant multi-trunked speciment like the one here above in an alluvial woodland ??? If you figure out the how and why, you'll be able to establish anything in a restoration project or urban landscape layout. Here's what I wrote about Bajadas or Alluvial Fans (2013).
Some other references regarding habitat restoration, especially riparian ecosystems