Month: June 2011

Cultural Lag: Public policy lags behind science regarding “invasion biology”

This is a good-news-bad-news story.  The good news is that the most successful environmental organization devoted to the preservation and conservation of wildlands, The Nature Conservancy, has announced its intention to reorder its priorities in what we hope will be a less destructive direction.  The Conservancy is a science-based environmental organization that is unique in that regard.  It employs over 600 scientists to guide and inform its projects, in contrast to many other organizations that employ more lawyers than scientists.  The scientific orientation of the Conservancy undoubtedly puts it in a position to reflect and respond to the increasingly loud voices of other scientists who are expressing concern about the costs and environmental damage that are the unintended consequences of the “restorations” which have evolved out of invasion biology.

The bad news is that public policy regarding native plant “restorations” lags far behind the developing scientific consensus regarding invasion biology, namely that original theories require revision.  This is the consequence of the cultural lag that is inevitable when science moves forward, but communication of its findings to the general public lags behind. 

The Nature Conservancy redefines its goals

In the past few months, the Chief Scientist of the Nature Conservancy, Peter Kareiva, has written several articles in the Conservancy’s publications expressing his views about the future of conservation.  In “Beyond Man vs Nature,”(1) Kareiva is quoted as saying that species preservation should not be the top priority of the Conservancy.  He admits he is “not a biodiversity guy.”  Rather, he says, “The ultimate goal [should] be better management of nature for human beings.”  He does not agree with those who claim that the earth is fragile and man must be excluded from nature in order to protect it.  He considers nature resilient.  He calls the concept of “biodiversity hot spots” sham science and he rejects the notion that conservation and development are mutually exclusive.  We wants conservation efforts to focus on the things that people need from nature such as clean water and clean air.  If and when people experience the benefits of conservation, they will support and participate in those efforts.  The Conservancy can’t save the world alone.  The active participation of the human population is required to achieve the Conservancy’s conservation goals. 

Golden Gate Park San Francisco. Most plants and trees in GG Park are not native. Creative Commons Attribution - Share Alike

In “Conservation should be a walk in the park, not just in the woods,”(2) Kareiva says that the Conservancy should participate in more urban conservation projects because that’s where most people live and even more will live in the future.  He wants conservation to be more visible to people and he wants people to benefit directly from the projects.

In his most recent publication, “Invasive Species:  Guilty until proven innocent?” Kareiva acknowledges the debate about invasive species.  On the one hand, a few invasive species have done a great deal of harm, particularly on islands.  On the other hand, many invasive species aren’t doing any harm and some are benefitting native species, even endangered species in some cases (e.g., Southwestern Willow Flycatcher in Tamarisk).  He concludes, “Science-based conservation cannot be about knee-jerk platitudes and simple views of good and evil…the fact is we cannot control all invasive species, and in many cases, yesterday’s invaders have become plants and animals that are beloved by local people.” 

There is nothing scientifically new to us in what Kareiva has said recently.  What’s new is that he speaks as a representative of one of the most important environmental organizations in the world.  Therefore, he makes a connection between scientific theory and action.  That is new….very, very, new and very encouraging.

Public policy always lags behind science

Public policy is inherently conservative.  It usually reflects consensus and consensus occurs late in every scientific debate.  Once that consensus is finally reached, changing it is a slow process.  And so, we are not surprised by the most recent example of a local community continuing the crusade to eradicate non-native trees.  Two ordinances were recently passed in the Los Altos Hills on the San Francisco peninsula, to do just that. 

  • Citizens building or expanding buildings on their properties will be required by ordinance 10-2.802 to cut down all eucalypts within 150 feet of any roadway or structure.
  • “Town guidelines concerning restoration action” (5-8.08) “deems certain trees undesirable,” including Monterey pine and cypress, as well as eucalyptus.

We are heartened by the publication which announces these new policies.  The author objects to being dictated to regarding her tree preferences.   She also responds to the usual myths regarding the negative qualities of eucalyptus.  In response to the usual justification for its eradication, that it is not native, the author says, “Who cares?”  Indeed, who cares?  We certainly don’t care and we speculate that the vast majority of people in Los Altos Hills don’t care either.  When we speak up on behalf of our trees, we speed the process of changing public policy to reflect the considerable scientific evidence that non-native trees are not harming anything or anyone.   Indeed, their eradication is causing far more harm to the environment by releasing tons of sequestered carbon and requiring greater herbicide use.    

(1) Nature Conservancy, Spring 2011

(2) Nature Conservancy, Issue 2, 2011

Fortress Conservation: The loss of recreational access

Sharp Park, Pacifica, CA. Photo by Erica Reder, SF Public Press

The recent publication of an article about Sharp Park in Pacifica, featuring a photo of this sign has inspired us to consider the recreational access restrictions that often accompany native plant and animal conservation projects.

In this case, an 18-hole golf course in Sharp Park is at stake.  A coalition of environmental organizations (1) recently sued the City of San Francisco to close this golf course, based on their claim that the golf course violates the Endangered Species Act by harming two endangered species (Red-legged frog and San Francisco garter snake).  The City of San Francisco claims that the golf course can be reconfigured to accommodate these species.  Meanwhile, conservation efforts requiring closure of recreational areas, according to this sign, are continuing.

The organizations that have sued San Francisco also claim that the closures they demand will actually improve recreational opportunities.  This claim is based on an assumption that the preferred form of “recreation” is standing on a trail or boardwalk behind a fence, looking at wildlife through binoculars.  Naturally, people who play golf see it otherwise.

We don’t claim to know the needs of these particular endangered species.  However, based on similar claims in other parks, we are skeptical.  In our experience, environmentalists—and sometimes park managers—often claim that animals are more fragile than scientific evidence or actual experience suggests.  We therefore suspect that animals are sometimes used by environmentalists and park managers to justify closing recreational areas. 

Loss of recreational access at Fort Funston, San Francisco

In a series of closures from 1997 to 2000, the Golden Gate National Recreation Area (GGNRA) fenced visitors out of more than 28 acres of Fort Funston (about 15% of total acreage), claiming the land was “bank swallow habitat” and that the swallows needed the closures for protection of their breeding colony.  In fact, the fenced land is not bank swallow habitat.  The swallows do not nest, breed, feed, roost, or do any of the normal activities a bird does in its habitat, inside the closures.  The swallows fly over it on their way from their nests on the cliff face above the beach to Lake Merced where they feed on insects.  The GGNRA sponsored a study(2) of wildlife in the fenced areas during the breeding season of the swallows, when the swallows were present.  The study included a census of all birds observed inside the enclosure and reported not a single bank swallow.

A swallow expert, William M. Shields, SUNY Professor of Biology, said of the closures, “I do not believe that a closure of the size and type described by the park service is required or even would benefit the Bank Swallow at all.”  He said that the closure was based on “…their [GGNRA’s] misrepresentations about the needs and safety of the Bank Swallows breeding in the cliffs.”  Dr. Shields classified GGNRA’s claims of providing improved feeding habitat as, “…a major stretch and smacks of special pleading to me.”

Bank swallow burrows (circled) in cliff above beach at Fort Funston

The bank swallows nest in burrows in the cliff faces at Fort Funston, where they are out of reach of recreational visitors who seldom even notice the presence of the birds.  Furthermore, as Dr. Shields notes, “The Bank Swallow like other swallows is quite suited to live with humans and their pets.”  Another swallow expert, Barrett Garrison says in his monograph Bank Swallow, “Bank Swallows appear relatively insensitive to moderate levels of human-induced disturbance.”  Garrison lists documented land uses around Bank Swallow colonies:  hydroelectric power generation, irrigation, recreational boating, commercial agriculture, vehicular and pedestrian traffic, and livestock grazing.

Bank swallow nests in……
…a sheep pasture

When the public was fenced out of large areas of Fort Funston, the bank swallow was just a phony excuse.  We try to avoid speculating about the motivation of others, but in this case the massive native plant “restoration” that followed the closure seems the likely goal of the closure. 

Loss of recreational access at Albany Bulb in the East Bay

Frenced enclosure at Albany Plateau for theoretical burrowing owls

In 2008, 8 acres of the Albany Plateau (the flat area at the east end of the Albany Bulb) was fenced at a cost of $125,700.  The stated purpose of this fenced enclosure was to create habitat for the burrowing owl, although owls had never been seen nesting there.  Three years later there are still no burrowing owls in this fenced enclosure.  In fact, there is nothing in this fenced area and nothing is happening there.  Update:  Ten years later, no owls have been seen nesting there.  November 2017

How did we lose this recreational resource?  That is a fascinating story:  “During the planning process for the Eastshore State Park…the demonstration of community need for sports fields led to the designation of the eastern side of the Albany Plateau as “active recreation” land use category.  This was problematic because of its proximity to the Albany Mudflats State Sanctuary and because State Parks is not in the practice of operating formal sports fields facilities.”(3)  Consequently, the Tom Bates Regional Sports Complex south of Golden Gate Fields was approved for development as sports fields.  Unfortunately one burrowing owl had been seen (but was not nesting) in that area two years before.  Therefore, environmentalists demanded “mitigation” for the development of a sports field in that area.  The “mitigation” was the creation of the 8-acre fenced enclosure on the Albany Plateau.  So far, burrowing owls have not elected to use the fenced area.

But why would a burrowing owl choose to nest on the Albany Plateau when it has a nesting area just a few miles down the road at the Cesar Chavez Park?  Burrowing owls can be seen nesting at Cesar Chavez Park every year from October to April.  There are post-and-rope fences that designate their nesting area, but those fences are not impenetrable as is the chain link fence on the Albany Plateau.  People (often with their dogs on leash) walk on trails within 20 feet of the owls.  The owls don’t seem disturbed by this activity and apparently prefer the busy Cesar Chavez Park to the fenced Albany Plateau.

Burrowing owl, Cesar Chavez Park, Berkeley

Are animals being used as tools to restrict recreational access?

We wish the animals could speak for themselves.  Do they require the enclosures that environmentalists demand for them?  We think the answer to that question is sometimes “NO!”  And when environmentalists make these claims repeatedly, do they lose their credibility when the evidence indicates that such restrictions are in fact not needed?  In other words, are environmentalists crying wolf?  Or do they accomplish their true goals by successfully fencing people out of our parks?  Is their goal an example of Fortress Conservation or a sincere effort to protect animals from harm?  Do park managers prefer parks without people?

(1) Wild Equity Institute, Sierra Club, Audubon Society, National Parks Conservation Association, Center for Biological Diversity

(2) “Evaluating Wildlife Response to Coastal Dune Habitat Restoration in San Francisco, California” by Will Russell, Jennifer Shulzitski and Asha Setty, Ecological Restoration, Vol. 27, No. 4, 2009

(3) City of Albany City Council Agenda Staff Report

Facts about carbon storage in grasses do not support assumptions of native plant advocates

We have received many comments from native plant advocates regarding carbon storage.  These comments defend projects in the Bay Area to destroy non-native forests and “restore” native plants by claiming that native plants will actually sequester more carbon than the forest that they propose to destroy.  As always, we are grateful for comments that give us the opportunity to research the issues and report what we have learned about this complex and important subject.

Carbon cycling in a terrestrial plant-soil system

The storage of carbon in plants and soil occurs as plants and soil exchange carbon dioxide (CO₂) with the atmosphere as a part of natural processes, as shown in the following diagram (1):

Green Arrow:  CO₂ uptake by plants through photosynthesis

Orange Arrows:  Incorporation of Carbon into biomass and Carbon inputs into soil from death of plant parts

Yellow Arrows:  Carbon returns to the atmosphere through plant respiration and decomposition of litter and soil Carbon.  Carbon in plant tissues ultimately returns to atmosphere during combustion or eventual decomposition.

Rates of carbon uptake and emissions are influenced by many factors, but most factors are related to temperature and precipitation:

  • Higher temperatures are associated with faster plant growth, which accelerates photosynthesis and carbon uptake.
  • Higher temperatures also accelerate decomposition of plant materials, thereby accelerating the return of stored carbon into the atmosphere.
  • The effect of moisture in the soil on decomposition can be graphed as a “hump.”  In extremely dry soils, decomposition is slow because the organisms that decompose vegetation are under desiccation stress.  Conditions for decomposition improve as moisture in the soil increases until the soil is very wet when lack of oxygen in the soil impedes decomposition.

Although temperature and precipitation are important factors in carbon storage, they don’t change appreciably when one type of vegetation is replaced with another.  Therefore, these factors aren’t helpful in addressing the fundamental question we are considering in this post, which is “Does native vegetation store more carbon than the forests that presently occupy the land in question?”

Where is carbon stored?

Source: U.S. EPA, 2018

Much of the carbon stored in the forest is in the soil.  It is therefore important to our analysis to determine if carbon stored in the soil in native vegetation is greater than that stored in non-native forests.  The answer to that question is definitely NO!  The carbon stored in the soil of native vegetation in Oakland, California is a fraction (5.7 kilograms of carbon per square meter of soil) of the carbon stored in residential soil (14.4 kilograms in per square meter of soil). (9)  Residential soil is defined by this study as “residential grass, park use and grass, and clean fill.”  This study (9) reports that the amount of carbon stored in the soil in Oakland is greater after urbanization than prior to urbanization because Oakland’s “wildland cover” is associated with “low SOC [soil organic carbon] densities characteristic of native soils in the region.”

Native plant advocates have also argued that the carbon stored in the soil of perennial native grasslands is greater than non-native trees because their roots are deeper.  In fact, studies consistently inform us that most carbon is found in the top 10 centimeters of soil and almost none is found beyond a meter (100 centimeters) deep. (1, 4) In any case, we do not assume that the roots of perennial grasses are longer than the roots of a large tree.

Another argument that native plant advocates use to support their claim that native perennial grasslands store more carbon in the soil than non-native trees is that native grasses are long-lived and continue to add carbon to the soil throughout their lives.  In fact, carbon stored in the soil reaches a steady state, i.e., it is not capable of storing additional carbon once it has reached its maximum capacity. (1)

It is pointless to theorize about why grassland soils should store more carbon than forest soils.  The fact is they don’t.  In all regions of the United States forest soils store more carbon than either grassland or shrubland soils.  (9, Table 5)

We should also describe Oakland’s native vegetation before moving on:  “Vegetation before urbanization in Oakland was dominated by grass, shrub, and marshlands that occupied approximately 98% of the area.  Trees in riparian woodlands covered approximately 1.1% of Oakland’s preurbanized lands…”  (5)  In other words, native vegetation in Oakland is composed of shrub and grassland.  When non-native forests are destroyed, they will not be replaced by native trees, especially in view of the fact that replanting is not planned for any of the “restoration” projects in the East Bay.

The total amount of carbon stored within the plant or tree is proportional to its biomass, both above ground (trunk, foliage, leaf litter, etc.) and below ground (roots).  Since the grass and shrubs that are native to the Bay Area are a small fraction of the size of any tree, the carbon stored within native plants will not be as great as that stored in the trees that are being destroyed.

Whether we consider the carbon stored in soil or within the plant, the non-native forest contains more carbon than the shrub and grassland that is native to the Bay Area.

Converting forests to grassland

If we were starting with bare ground, it might be relevant to compare carbon sequestration in various types of vegetation, but we’re not.  We’re talking about specific projects which will require the destruction of millions of non-native trees.  Therefore, we must consider the loss of carbon associated with destroying those trees.  It doesn’t matter what is planted after the destruction of those trees, nothing will compensate for that loss because of how the trees will be disposed of.

The fate of the wood in trees that are destroyed determines how much carbon is released into the atmosphere.  For example, if the wood is used to build houses the loss of carbon is less than if the wood is allowed to decompose on the forest floor.  And that is exactly what all the projects we are discussing propose to do:  chip the wood from the trees and distribute it on the forest floor, also known as “mulching.”  As the wood decomposes, the carbon stored in the wood is released into the atmosphere:  “Two common tree disposal/utilization scenarios were modeled:  1) mulching and 2) landfill.  Although no mulch decomposition studies could be found, studies on decomposition of tree roots and twigs reveal that 50% of the carbon is lost within the first 3 years.  The remaining carbon is estimated to be lost within 20 years of mulching.  Belowground biomass was modeled to decompose at the same rate as mulch regardless of how the aboveground biomass was disposed” (8)

Furthermore, the process of removing trees releases stored carbon into the atmosphere, regardless of the fate of the destroyed trees:  “Even in forests harvested for long-term storage wood, more than 50% of the harvested biomass is released to the atmosphere in a short period after harvest.”  (1)

Will thinning trees result in greater carbon storage?

Native plant advocates claim that thinning the non-native forest will result in improved forest health and therefore greater carbon storage.  In fact, the more open canopy of an urban forest with less tree density results in greater growth rates.  (3)  Although more rapid growth is associated with greater rates of carbon sequestration, rates of storage have little effect on the net carbon storage over the life of the tree.  (6)  Net carbon storage over the life of the tree is determined by how long the species lives and how big the tree is at maturity.  These characteristics are inherent in the species of tree and are little influenced by forest management practices such as thinning. (6)

More importantly, even if there were some small increase in carbon storage of individual trees associated with thinning, this increase would be swamped by the fact that over 90% of the urban forest will be destroyed by the proposed projects we are evaluating in the East Bay.  The projects of UC Berkeley and the City of Oakland propose to destroy all non-native trees in the project areas.  The project of the East Bay Regional Park District proposes to destroy all non-native trees in some areas and thin in other areas from 25 to 35 feet between each tree, reducing tree density per acre by at least 90%.  No amount of “forest health” will compensate for the loss of carbon of that magnitude.   

Responding to native plant advocates

  • The vegetation that is native to the Bay Area does not store more carbon above or below the ground than the non-native forest.
  • Chipping the trees that are destroyed and distributing the chips on the ground will not prevent the release of carbon from the trees that are destroyed.
  • Thinning the trees in our public lands will not increase the capacity of the trees that remain to store carbon.

 ————————————————————————————————–

Bibliography

  1.  Anderson, J., et. al., “The Potential for Terrestrial Carbon Sequestration in Minnesota, A Report to the Department of Natural Resources from the Minnesota Terrestrial Carbon Sequestration Initiative, February 2008.
  2. Birdsey, Richard, “Carbon storage and accumulation in United States Forest Ecosystems,” USDA Forest Service, General Technical Report WO-59, 1992
  3. Environmental Protection Agency, “Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2008,” April 15, 2010., EPA 430-R-10-006
  4. Fissore, C.,  et.al., “Limited potential for terrestrial carbon sequestration to offset fossil-fuel emissions in the upper Midwestern US,” Frontiers in Ecology and the Environment, 2009, 10.1890/090059
  5. Nowak, David, “Historical vegetation change in Oakland and its implication for urban forest management,” Journal of Arboriculture, 19(5): September 1993
  6. Nowak, David, “Atmospheric Carbon Reduction by Urban Trees,” Journal of Environmental Management, (1993) 37, 207-217
  7. Nowak, David. Crane, Daniel, “Carbon storage and sequestration by urban trees in the U.S.A.,” Environmental Pollution, 116 (2002) 381-389
  8. Nowak, David, et.al., “Effects of urban tree management and species selection on atmospheric carbon dioxide,” Journal of Arboriculture 28(3) May 2002
  9. Pouyat, R.V. (US Forest Service)., et.al., “Carbon Storage by Urban Soils in the United States,” Journal of Environmental Quality, 35:1566-1575 (2006)

Spartina alterniflora: Treasured on the East Coast, reviled on the West Coast

Spartina alterniflora (Smooth Cordgrass) is a species of marsh grass native to the Atlantic and Gulf coasts of the United States, where it is considered a valuable plant making important contributions to the coastal ecology:

  •  Its dense growth provides protection against storm surge and “erosion control along shorelines, canal banks, levees, and other areas of soil-water interface.”(1)
  • It filters nutrients, sediments and toxins from the water that flows off the land before reaching the ocean, acting as a natural water treatment facility.
  • It provides cover and food for birds, mammals and marine animals that live in the coastal marsh.  Many other marsh plants occupy the same marshlands.

    Spartina alterniflora, Smooth Cordgrass. USDA photo

Where Smooth Cordgrass has died back in its native range, the dieback has been considered a serious environmental threat:

  • In 2001 the Governor of Louisiana declared a “state of emergency” when Smooth Cordgrass declined and the state obtained $3 million of federal funding to study and hopefully reverse the decline.  This study resulted in the development of a method of aerial seeding of Smooth Cordgrass to restore declining areas of marshland.(2)
  • A similar, but smaller dieback of Smooth Cordgrass in Georgia led to a collaborative research and on-going monitoring effort by 6 research institutions in Georgia.(3)
  • Similar dieback of Smooth Cordgrass has been reported as far north as the coast of Maine.  A researcher at the Connecticut Agricultural Experiment Station is quoted in that report as saying, “In New Orleans, if their marshes were intact, the storm surge of Katrina would not have reached the levees.”(4)

The war on Smooth Cordgrass in the West Coast 

Smooth Cordgrass is not native on the Pacific Coast of the United States.  Therefore it is treated as an alien invader to be eradicated with herbicides:

  • $24 million was spent to eradicate Smooth Cordgrass in San Francisco and Willapa Bay from 2000 to 2010 (5)
  • $16.3 million is projected to be spent on eradication efforts on the entire West Coast from 2011 to 2020 (6)

In 2006, 2,000 acres were treated with herbicides to eradicate Smooth Cordgrass in the San Francisco Estuary.    Most were retreated 3 to 5 times after initial treatment.  In 2010, twenty five sites were slated for retreatment, usually with herbicides.  The San Francisco Estuary Invasive Spartina Project (ISP) “defines a need for a zero tolerance threshold on invasive Spartina in the San Francisco Bay.”(7)

The ISP reports that imazapyr (Habitat) will be used in most sites, although it will sometimes be mixed with glyphosate (Roundup). (See SaveSutro for more information about imazapyr and its use in San Francisco.)  The ISP acknowledges that:

  •  “little is known about the interactive effects” of combining these herbicides or any of the surfactants used with these herbicides.
  • These herbicides will be applied using a variety of methods, including aerial spraying by helicopter.
  • Although the ISP considers imazapyr a relatively non-toxic herbicide, it also acknowledges that imazapyr has only been used since 2005.  Therefore, “Only few toxicity studies exist for birds…no data exist for the potential toxicity of imazapyr to shorebirds.”(8) Given that one of the stated purposes of eradicating Smooth Cordgrass is to benefit the endangered Clapper Rail, it seems surprising that nothing is known about the effects of imazapyr on any shorebird, including the Clapper Rail.

Why is Smooth Cordgrass treasured on the East Coast and reviled on the West Coast?  That question was asked and answered by Professor James Morris at an Environmental Law Conference in Eugene, Oregon on March 5, 2011.  Professor Morris studies Smooth Cordgrass at the Baruch Institute for Marine & Coastal Sciences at the University of South Carolina.  We urge our readers to watch a video of his presentation to the conference in Oregon.  We will draw upon that video in addressing the claims (9) made by those who are attempting to eradicate Smooth Cordgrass on the West Coast:

Indictment:  Smooth Cordgrass will invade mud flats, eliminating valuable habitat for plants and animals that inhabit that segment of marshland.

Defense:  According to Professor Morris, Smooth Cordgrass was introduced to the West Coast in shipments of Eastern oysters over 100 years ago without eliminating mudflats.  Europe has had similar experience with Smooth Cordgrass which was introduced there to reduce sediment in harbors.  Professor Morris showed pictures of Danish and Dutch estuaries in which Smooth Cordgrass has existed since the 1930s without radically altering the composition of the marshland.

Indictment:  Smooth Cordgrass will invade waterways, making them impassable.

Defense:  Again, since this has not happened in 100 years, there is no reason to assume it will happen in the future.  Furthermore, the USDA describes the narrow range of Smooth Cordgrass:  “the width and thickness of vegetative colonies are controlled by a number of site specific conditions such as elevation, shoreline slope, and frequency, depth and duration of flooding” as well as salinity and acidity.  In other words, the range of Smooth Cordgrass is limited.

Indictment:  Smooth Cordgrass does not provide habitat value equal to the native species of cordgrass with which Smooth Cordgrass competes, particularly for the endangered Clapper Rail.

Defense:  Mike Casazza at the Dixon Field Station of the USGS is presently studying the effect of eradicating Smooth Cordgrass on the reproductive success of the Clapper Rail:  “Removal of invasive Spartina accomplishes the goal of Spartina eradication, but if rails fail to survive and reproduce, then the goal of species protection is unfulfilled…the potential for impact from invasive Spartina removal and the potential for mitigation by rail ecology and behavior remain poorly understood.”(10)  Clapper Rails live in Smooth Cordgrass on the East Coast:  “numerous” Clapper Rail families were observed nesting in Smooth Cordgrass on Dewees Island, South Carolina.(11)

Indictment:  Smooth Cordgrass is outcompeting the native Pacific Cordgrass (Spartina foliosa) by displacement and hybridization.

Defense:  This is probably true because of the characteristics of the Pacific Cordgrass:  “S. foliosa occupies a very limited range in the intertidal zone, and the leaves and stems wither in fall and shed in the winter, leaving sparse standing matter that is ineffective at trapping sediment.  Seedlings of S. foliosa are seldom found in established marshes and appear only intermittently in sheltered upper mudflats.”(12)  In other words, the range of the native cordgrass is narrower, it does not grow as densely, and it is not foliated year around, thereby creating opportunities for the non-native cordgrass to occupy bare ground.  Since marsh grasses are beneficial to the environment and its inhabitants, the ability of Smooth Cordgrass to occupy this vacuum seems a benefit, particularly since native cordgrass is less capable of removing sediments from water, reducing its effectiveness as a filter of pollutants from water flowing into the bay.(13)

Smooth Cordgrass is treasured on the East and Gulf Coasts because it performs valuable ecology services.  Although it performs the same ecological functions on the West Coast, it is being eradicated.  The evidence available to us suggests that we are spending a lot of money and effort, as well as using a lot of herbicides, to eradicate Smooth Cordgrass only because it is not native to the West Coast.   

  • Smooth Cordgrass provides superior storm surge protection particularly during winter months when native cordgrass is dormant.
  • Smooth Cordgrass is more capable of filtering pollutants from water flowing into the bay.
  • Smooth Cordgrass provides at least equal habitat quality to the endangered Clapper Rail and probably other marsh plants and animals as well.
  • Smooth Cordgrass has not blocked waterways or eliminated mud flats in comparable situations over long periods of time

We invite our readers to supply us with evidence that there are legitimate reasons for the campaign against Smooth Cordgrass.

(2) Dorset Hurley, “Geogia’s Marsh Die Back and Louisiana’s Marsh Browning,” Altamaha Riverkeeper

(3) Ibid.

(4) “What’s killing off our salt marshes,” Going Coastal Magazine, September 15, 2008

(5) “West Coast Governor’s Agreement on Ocean Health,” May 2010, page 5

(6) Ibid., page 6

(7) “San Francisco Estuary Invasive Spartina Project, 2010 Pesticide Application Plan,” page 15.

(8) Ibid. page 31

(9) “West Coast Governor’s Agreement on Ocean Health,” May 2010

(10) “Ecology of California Clapper Rail in the San Francisco Bay/Delta Region,” USGS Western Ecological Research Center

(11) Judy Drew Fairchild, “Watch for Clapper Rails and chicks,” Dewees Island, SC

(12)“West Coast Governors’ Agreement on Ocean Health,” May 2010, page 12

(13) “San Francisco Estuary Invasive  Spartina Project, 2010 Pesticide Application Plan,” page 10