There have been a number of posts made recently that discussed the issue of invasive species in wetlands. Jeremy started the current discussions by asking about giant reed research ideas. Mic****e then posed a question about control of reed canary grass (RCG) and asked –if you have a mitigation wetland surrounded by RCG is it feasible to meet a success criteria of <10% RCG? Invasive species issues have also been raised in response to other posts that were originally placed for different reasons, and which were not related to CWA 404 permitting.

The questions that I have seen raised (as per my interpretation and summary) seem to be:

1. Are invasive species regulated and/or should they be by the CWA?
2. Do we care about invasive species if they are not regulated by the CWA?
3. How do you control specific species?
4. Are certain control standards feasible in a mitigated wetland?
5. Can you establish a mitigation wetland in a landscape surrounded by invasive species and be expected to keep the adjacent invasive species out.

I suggest that we establish a new thread here and concentrate on questions #4 and 5 regarding mitigation wetland success criteria in wetlands surrounded by non-native. Dana suggested that a success criteria of <10% RCG might not be realistic in portions of the PNW. I have found use of reference wetlands very important in addressing non-natives in mitigation wetlands in that the mitigation wetland is not expected to be superior to the reference wetland in terms of non-native species composition. (Of course, there are also a lot of constraints and problems with the reference wetland concept). How do other individuals and/or agencies deal with this issue?

Johnny, I do hope that you will repeat your post and questions here.

Leslie posed 5 questions pertaining to invasive species and wetland mitigation and recommended that this thread focus on questions 4 and 5:

quote:

1. Are invasive species regulated and/or should they be by the CWA?
2. Do we care about invasive species if they are not regulated by the CWA?
3. How do you control specific species?
4. Are certain control standards feasible in a mitigated wetland?
5. Can you establish a mitigation wetland in a landscape surrounded by invasive species and be expected to keep the adjacent invasive species out.

I suggest that we establish a new thread here and concentrate on questions #4 and 5 regarding mitigation wetland success criteria in wetlands surrounded by non-native.

I think we should begin with considering the reason for compensatory mitigation and whether invasive species control can fit within that context. Typically, at least in theory, compensatory mitigation is done to provide replacement of ecological functions lost through unavoidable impacts to wetlands. To implement a mitigation project, one must either create wetlands where they previously did not occur or restore wetlands on areas where they formerly existed or where they still exist but in a degraded state. If, from an ecological perspective, a wetland that is overrun with invasive species is degraded, then one means of creating wetland value through restoration is to control exotic invasive species. This would not be an approach required by the regulatory community, but an approach chosen by an applicant to achieve the necessary lift in ecological value to offset impacts.

One might choose to do this for different reasons such as it is not feasible to create a wetland somewhere as establishing hydrology and earthmoving would be prohibitive or there is an onsite degraded wetland (already owned) that could be used if restored through control of exotics. Through the negotiation process, an invasives control approach agreeable to both sides is developed, including the success criteria. If appropriate success criteria relative to invasive species cannot be agreed to, then the applicant would be back to substituting a differnt restoration/creation project to fulfil the compensatory mitigation.
Because the mitigation planning process is (should be) a negotiation process, an applicant should never be faced with untenable success criteria as ther is no reason to agree to something that cannot be done within reason.

This gets us back to whether one can establish or restore a mitigation wetland in an area surrounded by invasives. The short answer is that for certain, unfortunately very diffiicult to control species, the answer had better be yes. Tallow and tamarisk leap immediately to mind. Both of these species are prodigious movers of water. If you need to create/restore 10 acres of wetlands to offset impacts and you have a 10-acre mitigation site, then you had better not have 10 acres of tallow or tamarisk. If you do, the odds are almost 1 that you will have much less than 10 acres of wetlands. The plants will likely eliminate the hydrology and convert the site to non-wetland.

I did not intend to provide complete answers to questions 4 and 5, just to provide a foundation for moving the thread forward. I did not attempt to address what success criteria would be appropriate - both from the standpoint of abundance of invasives or the time frame for the monitoring period or to come up with solutions to how to implement control measures. That should be our path forward.

I agree completely with the theory of compensatory mitigation and the idea that the mitigation planning process should be a negotiation process on what can and cannot not be done within reason. However, given the debate on whether or not mitigation is working as a whole, but especially with regard to invasive species, I tend to believe that there is a breakdown in the system (starting early in the "negotiating" process maybe) and that the reality of the situation is that potential invasive species are knocking at the back door (dare I say) of almost every mitigation area that has ever been constructed (not to mention almost every natural wetland too). The surrounding landscape/environment doesn't care about what performance/success criteria has been determined during the negotiation period. The system will become what the environment surrounding it wants it to become, right?

So, my questions: Are we focusing too much on the mitigation area itself? Should we think outside of the "box" and consider more of a landscape approach to compensatory mitigation? Or, do you believe that this discussion is currently taking place during the regulator/applicant negotiations?

One other question that I would like to see discussed further. If a mitigation was constructed (and is now a reedcanary grass patch - for example) within the same watershed as the wetland that was impacted, and say the impacted wetland was a reedcanary grass patch; isn't the mitigation functionally, at minimum, an in-kind replacement - functions and all? Are we to assume that because the pre-existing wetland was a reedcanary grass patch, that it was a degraded wetland and wasn't functioning as habitat like other wetlands in the landscape? Reedcanary grass is currently being recommended by the NRCS as a good soil erosion cover crop and fodder for livestock. I have also observed numerous wildlife and aquatic species while in reedcanary grass patches. I would say that reedcanary grass provides adequate habitat for a number of species.

Just some thoughts as I try to understand the causes and reasoning behind compensatory mitigation and how invasive species fit into planning/managing process.

This message has been edited. Last edited by: Michelle Selzer,

Whether an RCG wetland could be acceptable as a mitigation site (particularly with regard to final sign-off indicating a completed project with no further applicant responsibilities) would depend on the success criteria (It is a vicious loop.)and also on the regs the mitigation is implemented under.

If success criteris establish a maximum cover of invasive species and you are in an area where RCG is classified as an invasive, then an RCG wetland would not pass muster.

If success criteris specify a certain vegetation species diversity must be met and that diversity requires more than 1 dominant species in the herbaceous layer, then the RCG wetland would not be acceptable.

If you are in a state such as Ohio, where the state regs establish e categories of wetlands based on habitat quality and further require that compensatory mitigation wetlands (created or restored) be of moderate quality, then the RCG wetland would not pass muster. The state regs also define an invasive species monoculture (RCG is invasive in OH) as a low quality wetland, which is not suitable for mitigation.

The larger issue of what the surrounding landscape would drive the wetland to is a question od resource commitment and also of design. If the applicant is willing to commit the resources to controlling invasive species, it can be done. However, that position is generally not desirable from an economic standpoint and can lead to compensatory in theory becoming punitave in fact.

It is possible to design mitigation wetlands that will not be overrun by RCG in the midwest. However, whether that type of wetland would be acceptable (likely would not be in-kind) or economically feasible is another matter.

Let's say that a mitigation area was constructed according to the plans (seeded/planted - the works) and the invasive species criteria outlined in a permit issued was met at the end of the monitoring period with satifaction, do you believe that the mitigation would stand a better chance of not becoming overrun by a potentially invasive species that may be present in, or adjacent to, the wetland? If the answer is yes, how is it possible? Why do we see invasive species like purple loosestrife or phragmites move into what appears to be a natural "healthy" wetland system and eventually dominate? If we can't keep these species out of the natural wetlands, how can we expect to keep them out of the created wetlands?

With regards to a mitigation site, I clearly stated that a resource commirtment would be necessary to control the invasive species. For most mitigation sites, the invasion is going to happen.

However, it also is true that you can design and build a wetland (submerged aquatic plants) that has a hydrology that is unsuitable for establishment of RCG, purple loosestrife, and Phragmites. They can't invade where they can't establish. Of course milfoil and elodea could, but they do not as readily disperse to a closed site.

Unfortunately, these typically are not the wetland types that are impacted, so you end up with not in kind issues form a mitigation standpoint.

Going back to a couple of points Rich and Mic****e made earlier re mitigation in a watershed context-I am not sure that working at a watershed level would be punitive. One idea that I pursued a couple of years ago was to allow water rights to be dedicated to the local state resource agency for instream flows in agricultural areas. This was in a watershed in which the State already managed some instream flows, in which the river had been severely depleted by irrigation diversions, in which the agricultural wetlands that were jurisdictional were dominated by invasives, the agricultural land was being converted to housing and in which the historical wetlands (riparian forest) were struggling but not dramaticaly overrun by non-natives. I thought that the best mitigation would be to provide hydrologic support to the riparian wetlands in lieu of developing pasture wetlands in the middle of a housing development. I had a couple of developers quite excited about the idea but they decided to realize a short term economic gain in immediately selling the water rights, figuring that they would do mitigation with whatever money they had left at the end. In short, same old story that Johnny recounted so the idea didn't get very far but did have strong environmental group support. So, I do think that "out of the box" creative watershed level approaches can be done without being punitive, but I don't know of very many that have been done outside of a few SAMP's.

One thing that the COE has done in the past is allow for an in lieu payment, but its use now is very restricted and used for an established wetland restoration project that is short of funds (so that you can't just pay into a fee bank that can be used later). I am not sure if anyone is actively using this option anymore.

More comments on the other points raised in another post.

Regarding invasive species, Mic****e Selzer said;

"...If we can't keep these species out of the natural wetlands, how can we expect to keep them out of the created wetlands..?"

Dear Mic****e,

Thank you for posing the definitive question.

From the little bit that I have learned about wetlands mitigation, it appears to be a young science that emerged around 1986 when the Corps expanded it regulatory authority to include a new class of waters which it termed "waters of the United States."

It is not surprising that a few mistakes have been made, given limited scientific experience coupled with political pressures, and laws that are in a constant state of change. This is how I rationalize my understanding of those who expect (and sometimes demand) that we keep invasive species out of created wetlands.

Sometimes I drive by that old mitigation site, full of vibrant bright green tallow trees, and I search in vain for the oak trees that we planted. I shake my head. We gave them the benefit of the doubt because we needed a permit. We are right, they are wrong. Let us hope that responsible authorities, educated in the sciences and practiced in the field, will someday see their folly and change their minds.

This message has been edited. Last edited by: Johnny Stevens,

I am having some difficulty following this thread because I am not sure what an invasive plant is in the minds of others. I have always considered invasives to be non native plants that under some circumstances will invade and become overwhelmingly dominant on a site. Can native species be considered invasives? If so should we think about native and non native species differently in this context?

Invasive species = Nero's fiddle, "in this context".

Native vs. Non-native / Invasive vs. Non-invasive

I should think that it is very possible for a nonnative to be invasive .. but since preditors have coevolved they would be held at bay.

Thus it is non-native'ishness that enhances invasive'isness given that a non-native with invasive leanings in a native environment would become very invasive in a non-native environment.

Impact on clean water?
If the non-native fouls the water with its degrading product.. most likely

Gary poses an interesting question for this thread. Can a native species be an invasive. To answer this, one must first define native.
To do this, one must remember that the plants have not read the books or maps and have no concern for political boundaries. To this end, native should refer to the ecosystem (or ecosystems) that the species developed in.
This is the approach taken in Executive Order 13112 of February 3, 1999: Invasive Species, excerpted below:

(f) ‘‘Invasive species’’ means an alien species whose introduction does
or is likely to cause economic or environmental harm or harm to human
health.
(g) ‘‘Native species’’ means, with respect to a particular ecosystem, a
species that, other than as a result of an introduction, historically occurred
or currently occurs in that ecosystem.

The upshot of this is that a speices may be both native and non-native within a given political boundary. As I said, the plants have not read the books and laws or considered political boundaries.

Generally, a species would not become invasive within the ecosystem in which it developed. However, it is possible for a species with limited dispersal capabilities to develop in an isolated habitat surrounded by unsuitable habitat of sufficient size that dispersal is not possible naturally. If a means of dispersal becomes available that allows transport acorss the unsuitable habitat that casued the isoaltion of the species, then it could become invasive within its larger native ecosystem if it reaches other suitable habitat patches.

What has developed in practice is that USDA is the determinant of agricultural and most aquatic invasive species - those species that affect our crops, livestock, or boat access. The difference between an invasive species and a weed is paramount here, as many native species are classified as agricultural weeds.

Beyond that, states typically develop invasive species lists that focus on natural areas. The various Exotic Pest Plant Councils that have been organized in recent years try and identify those species that are non-native and encroaching on natural areas to the extent of displacing the native vegetation that created the natural resource value that led to the area being preserved. In application, many of the agricultural invasives will make the natural areas list, but the natural areas list will tend to be larger.

This then can lead us to attempting to determine what role the presence and subsequent control of invasive species should have in wetland mitigation.If a mitigation area is to be preserved, ultimately, as a natural area, then a success criterion of no more than some limited amount of invasive species would seem to be reasonable. As I have stated more than once, if part of the proposed mitigation is to achieve increased natural wetland habitat value through control of invasive species, and in so doing obtain a lesser mitigation ration, then committing to controlling invasive species would seem reasonable. If one of the mitigation goals is to provide hard mast species for small mammals and game animals and your oak species are displaced by tallow trees, then you end up with a lot of starving animals that must relocate or perish and clearly the mitigation goal is not met. The same would be true of a mitigation effort to create a sedge meadow - with its attendant habitat value and you end up with a field of RCG, phragmites, or purple loosestrife.

The ultimate question should be whether the presence of invasive species reduces the functional values that are to be created/enhanced. If the answer is yes, then some level of invasive species control would be warranted - the question then becomes how much and for how long? If the answer is no, then invasive species control, beyond what might be required by state or local law/ordinance would seem a superfluous demand on the applicant.

Regarding tallow tree wetlands mitigation, Richard Reaves said:

"...If one of the mitigation goals is to provide hard mast species for small mammals and game animals and your oak species are displaced by tallow trees, then you end up with a lot of starving animals that must relocate or perish and clearly the mitigation goal is not met..."

Dear Mr. Reaves,

Tallow tree forests cover millions of acres in southern states. I have read reports that tallow trees were introduced into this country over 200 years ago. Tallow trees thrive in both uplands and wetlands.

Your assertion that tallow tree forest is not suitable habitat for small animals and game animals is incorrect, but this argument is used to require out-of-kind mitigation for tallow tree wetlands. Tallow tree forests and wetlands provide habitat for small animals, snakes, skunks, raccoons, armadillos, wildcats, mice, rabbits, frogs, lizards, turtles, insects, wild hogs, deer, birds, and numerous plant species. Tallow tree forests often have dense underbrush which is inpenetrable for humans and difficult for hunting, but animals use this habitat.

My consultant challenged the presumption that tallow tree forest is degraded habitat, and the agencies responded by delaying our permit. They never justified this presumption so I remain skeptical. The Corps should update its policies and authorize like-kind mitigation for tallow tree wetlands.

Tallow forests have become established in southern states and should be recognized as a "naturalized" ecosystem.

Na. vs. No. / In. vs No. comments.

With Exec lingo and textbook descriptions aside, we are dealing with, and are talking about, a lot of "invasive" plant species that have been around for a long time, likely introduced by a variety of vectors including birds (e.g., migratory birds), animals, humans, etc.; are usually generalists with high genetic diversity - they grow where ever there's suitable habitat (with and without predators); and can occur over a variety of hydrologic regimes and proliferate if their environment is ideal. Now that to me is an adequate description/definition of the invasive plants that have been discussed thus far.

From a resource perspective, is there currently a conflict in management strategies when it comes to addressing invasive species in mitigation areas?

Applicants are obligated to manage for invasive species outlined in their permit, but at the end of the monitoring/managing period,after the conservation easement has been recorded and the consultant has left the building (I mean the mitigation area); who's the responsible party that ensures, as Reaves has stated, the mitigation achieves increased natural wetland habitat value?

Who's making sure that invasive species are continually managed and that the desired species aren't displaced?

From a regulatory perspective what, if any, resource commitments are in place to maintain the potential net gain from not-in-kind mitigation?

I'm not going to comment on the natural area invasion issue, though it disheartens me even more. Maybe on a different thread, some other day.

quote:

Your assertion that tallow tree forest is not suitable habitat for small animals and game animals is incorrect, but this argument is used to require out-of-kind mitigation for tallow tree wetlands. Tallow tree forests and wetlands provide habitat for small animals, snakes, skunks, raccoons, armadillos, wildcats, mice, rabbits, frogs, lizards, turtles, insects, wild hogs, deer, birds, and numerous plant species. Tallow tree forests often have dense underbrush which is inpenetrable for humans and difficult for hunting, but animals use this habitat.

While I do not know the basis for the above statement by Mr. Stevens, it is neither entirely correct as applied to my original statement nor is it entirely correct with regard to the ecology of tallow tree forests in the United States.

My statement was that if a mitigation goal (agreed to in mitigation plan) was to provide hard mast species for small mammals and game species and the mitigation goal would not be met if tallow eliminated all the oaks, which would result in those mast-dependent animals dying or relocating. Nothing in the above reply would rebut that statement.

Secondly, the assertion of the wonderful habitat values of tallow tree forests is demonstrably false. Tallow forests develop into a near monoculture. They lack herbaceous understory and prevent the growth of other woody species by winning the battle for the light.

As I peruse my book on wildlfie foods, I notice not a single species documented eating tallow tree roots, shoots, or fruit. Seems like someone would have found that the plant is used by some species in 200+ years if it was valuable for wildlife. Even chinaberry shows up as used by some birds in the wildlife book, so they were not avoiding exotic species in their gtallies. Granted there are birds that spread the seeds around, but it seems the spread and damage done by the species far exceeds the perceived utility of the species.

Based on a personal sample size of 200+ tallow woodlots of various stages of development throughout surveyed the southeast, I can state with certainty that "numerous plant species" do not occur in (use, in Mr. Stevens quote) tallow forests. It is true that numerous plant species occur in the forests that are invaded by tallow, but once the tallow is established those species are displaced and the plant diversity approaches 0. I have been in more than one acre+ sized patch where nothing but tallow grew at any level in the forest. The species will invade forests or grasslands - clearly an area converted from grassland to tallow trees no longer supports the grassland species.

Interesting that tallow is classified as an agricultural weed in Taiwan. Apparently it is not just this country that has a problem with the species.

If one totally ignores the loss of natural areas, the economic loss to the country from lost of bottomland timber resources and increased costs of forest products brought on by the necessity of control of this species to allow successful timber stand replacement in areas where tallow occurs is sufficient to warrant its classification as a noxious weed.


Now to return to the pint of this thread. When and to what extent should exotic species control be a component of an agreed to mitigation plan and how are or should success criteria be tied to exotic control.

As I mentioned before, one method may be to establish a mitigation site with habitat characteristics that are unsuitable for establishemtn of the exotic invasive du jour. However, this is frequently difficult with the requirement for in-kind mitigation. Therefore, for practical purposes, I thinnk that approach can be eliminated from further discussion.

Another approach would be to design the mitigation such that the introduction of the invasive would be deterred. Not possibly with a host of wind-dispersed exotics and extrmemly difficult with any bird dispersed exotic. Again, not suitable for further discussion as it is impractical for most of the species we are concerned with.

That brings us back to active control, monitoring, contingencies, and a timetable. How much, how successful, and for how long? All to be considered in the framework of satisfactory mitigation that does not become an excessive burden on the applicant.


More thoughts on this next post. Happy Thanksgiveing to all.

I would like to compliment Rich and Mic****e for their excellent discussion about invasive species issues. However, I still think it would be fruitful to go back to Rich’s first comment in which he discussed the trade-offs that people make during wetland permitting. As Rich stated so well, there is a sequence to go through during 404 permitting that can end up with a compensatory mitigation need. The applicant then proposes a mitigation project, with specific success criteria and timelines of implementation. If an applicant chooses enhancement through “weed” control and planting then that is what they need to do. If it doesn’t succeed, then it needs to be redone, as upon permit issuance, a contract is entered into.

Johnny stated earlier that the permittee in the tallow forest choose to go with a lower cost method of establishing oaks–that is use seed instead of tubelings as was recommended (specified in the plan?) When that happens, I can’t help but think that a permittee is trying to going through a process without producing a product. So, if I seed, regardless of the seed source, quality, timing, weather, etc. if it doesn’t work, I’m off the hook–there are too many adjacent non-native plants for this to succeed.

I’d like to distinguish between (1) the “see what I told you approach” in which specifications were only partially followed with an end result of a non-native species domination, (2) following specifications with monitoring, and (3) a real effort vs a understanding that this can’t work so that a functional plan is developed as to what can work and what can’t AND the permittee still gets to ok and sign off on it.


Any plan that really can’t work needs to be rejected. A plan that can work needs to be implemented as designed. There is no successful plan that I know of that can restore, create or enhance a wetland without follow-up monitoring or adjustment.

Regarding invasive species and wetlands mitigation, Rich Reaves said,

”That brings us back to active control, monitoring, contingencies, and a timetable. How much, how successful, and for how long? All to be considered in the framework of satisfactory mitigation that does not become an excessive burden on the applicant.”

Dear Rich,

Active control, monitoring, contingencies, and a timetable may be appropriate for landscaping and gardens. Wetland mitigation should achieve a natural eco-system that can thrive without human interference and maintenance.

Wetlands mitigation becomes an excessive burden when in-kind mitigation is replaced with high priced out-of-kind mitigation along with requirements for active control, monitoring, contingencies, and penalties for non-compliance with the mitigation plan.

Despite Rich’s distaste for tallow tree forests, this is the dominant eco-system on millions of acres throughout the South. Tallow tree wetlands are very common and have demonstrably good functional values, so I question why out-of-kind mitigation would even be considered for such wetlands. From my experience, out-of-kind mitigation for tallow wetlands usually fails, while in-kind mitigation is successful, cost effective, does not require active control, replaces lost functions, and is not an excessive burden on the permit applicant.

Johnny,
Do you have any journal articles substanting a good functional value of tallow forest? How about articles on melaleuca forests while your at it? I am really interested in your claims.
Ray

Ray,

I do not have journal articles or other scientific data to substantiate my claim that tallow tree wetlands provide good functions. My opinion is based on personal observations.

Tallow tree wetlands filter and retain stormwater which reduces flooding and recharges ground water. These wetlands also provide aquatic habitat to numerous plants and animals. These functions can easily be replaced by like-kind mitigation.

Tallow tree wetlands may not have the same functions and values as cypress tree wetlands, but this no reason to dismiss the functions that are provided. More importantly, functional values should be calibrated to match the dominant eco-system within the larger region of a proposed mitigation site.

Pre-existing wetland types, should not be mandated if such wetlands must compete against the larger eco-system. If new wetlands blend in with existing dominant wetlands types, then the mitigation process is more successful.

This message has been edited. Last edited by: Johnny Stevens,

IAM NOT FAMILIAR WITH METHODS THAT HAVE BEEN USED TO CONTROL TALLOW TREE. CAN YOU HELP ME TO UNDERSTAND WHAT METHODS HAVE BEEN USED AND WHY THEY WORK OR NOT.