Endangered and Threatened Wildlife and Plants; Proposed Designation of Critical Habitat for the Cirsium hydrophilum, 18456-18493 [06-3343]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 71, Number 69 (Tuesday, April 11, 2006)]
[Proposed Rules]
[Pages 18456-18493]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 06-3343]



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Part III





Department of the Interior





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Fish and Wildlife Service



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50 CFR Part 17



Proposed Designation of Critical Habitat for the Cirsium hydrophilum 
var. hydrophilum (Suisun thistle) and Cordylanthus mollis ssp. mollis 
(soft bird's-beak); Proposed Rule

Federal Register / Vol. 71, No. 69 / Tuesday, April 11, 2006 / 
Proposed Rules

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AU44


Endangered and Threatened Wildlife and Plants; Proposed 
Designation of Critical Habitat for the Cirsium hydrophilum var. 
hydrophilum (Suisun thistle) and Cordylanthus mollis ssp. mollis (soft 
bird's-beak)

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to 
designate critical habitat for Cirsium hydrophilum var. hydrophilum 
(Suisun thistle) and Cordylanthus mollis ssp. mollis (soft bird's-beak) 
pursuant to the Endangered Species Act of 1973, as amended (Act). 
Approximately 2,119 acres (ac) (857 hectares (ha)) fall within the 
boundaries of the proposed critical habitat designation for C. 
hydrophilum var. hydrophilum in Solano County, California, and 
approximately 2,313 ac (936 ha) for C. mollis ssp. mollis in Contra 
Costa, Napa, and Solano Counties, California.

DATES: We will accept comments from all interested parties until June 
12, 2006. We must receive requests for public hearings, in writing, at 
the address shown in the ADDRESSES section by May 26, 2006.

ADDRESSES: If you wish to comment, you may submit your comments and 
materials concerning this proposal by any one of several methods:
    1. You may submit written comments and information to Field 
Supervisor, U.S. Fish and Wildlife Service, Sacramento Fish and 
Wildlife Office, 2800 Cottage Way, Room W-2605, Sacramento, California 
95825.
    2. You may hand-deliver written comments to our Office, at the 
above address.
    3. You may send comments by electronic mail (e-mail) to 
SuisunplantsCH@fws.gov. Please see the Public Comments Solicited 
section below for file format and other information about electronic 
filing.
    4. You may fax your comments to (916) 414-6713.
    5. Federal eRulemaking Portal: https://www.regulations.gov. Follow 
the instructions for submitting comments.
    Comments and materials received, as well as supporting 
documentation used in the preparation of this proposed rule, will be 
available for public inspection, by appointment, during normal business 
hours at Sacramento Fish and Wildlife Office, 2800 Cottage Way, Room W-
2605, Sacramento, California 95825 (telephone (916) 414-6600).
    For more information on submitting or viewing comments, see 
``Public Comments'' under SUPPLEMENTARY INFORMATION.

FOR FURTHER INFORMATION CONTACT: Arnold Roessler, Listing Branch Chief, 
Sacramento Fish and Wildlife Office, 2800 Cottage Way, Room W-2605, 
Sacramento, California 95825, (telephone (916) 414-6600; facsimile 
(916) 414-6713).

SUPPLEMENTARY INFORMATION:

Public Comments

    We intend that any final action resulting from this proposal be as 
accurate and as effective as possible. Therefore, comments or 
suggestions from the public, other concerned governmental agencies, the 
scientific community, industry, or any other interested party 
concerning this proposed rule are hereby solicited. Comments 
particularly are sought concerning:
    (1) The reasons any habitat should or should not be determined to 
be critical habitat as provided by section 4 of the Act, including 
whether the benefit of designation will outweigh any threats to the 
subspecies due to designation;
    (2) Specific information on the amount and distribution of Cirsium 
hydrophilum var. hydrophilum and Cordylanthus mollis ssp. mollis 
habitat, and what habitat is essential to the conservation of the 
subspecies and why;
    (3) Land use designations and current or planned activities in the 
subject areas and their possible impacts on proposed critical habitat;
    (4) Any foreseeable economic, national security, or other potential 
impacts resulting from the proposed designation and, in particular, any 
impacts on small entities;
    (5) Whether our approach to designating critical habitat could be 
improved or modified in any way to provide for greater public 
participation and understanding, or to assist us in accommodating 
public concerns and comments;
    (6) Whether State-, county-, or local government-managed lands that 
are within the proposed designation should be excluded from the 
designation; and
    (7) The relative benefits of designation or exclusion of any lands 
for Cirsium hydrophilum var. hydrophilum and Cordylanthus mollis ssp. 
mollis in the Suisun Marsh (see Suisun Marsh Management Strategies 
section for specifics).
    (8) Information concerning pollinator species for C. mollis spp. 
mollis and whether sufficient information exists to determine if such a 
feature should be considered a primary constituent element for the 
subspecies.
    If you wish to comment, you may submit your comments and materials 
concerning this proposal by any one of several methods (see ADDRESSES 
section). Please submit Internet comments to SuisunplantsCH@fws.gov in 
ASCII file format and avoid the use of special characters or any form 
of encryption. Please also include ``Attn: Suisun Plants CH'' in your 
e-mail subject header and your name and return address in the body of 
your message. If you do not receive a confirmation from the system that 
we have received your Internet message, contact us directly by calling 
our Sacramento Fish and Wildlife Office at phone number (916) 414-6600. 
Please note that the Internet address SuisunplantsCH@fws.gov will be 
closed out at the termination of the public comment period.
    Our practice is to make comments, including names and home 
addresses of respondents, available for public review during regular 
business hours. Individual respondents may request that we withhold 
their home addresses from the rulemaking record, which we will honor to 
the extent allowable by law. There also may be circumstances in which 
we would withhold from the rulemaking record a respondent's identity, 
as allowable by law. If you wish us to withhold your name and/or 
address, you must state this prominently at the beginning of your 
comment, but you should be aware that the Service may be required to 
disclose your name and address pursuant to the Freedom of Information 
Act. However, we will not consider anonymous comments. We will make all 
submissions from organizations or businesses, and from individuals 
identifying themselves as representatives or officials of organizations 
or businesses, available for public inspection in their entirety. 
Comments and materials received will be available for public 
inspection, by appointment, during normal business hours at the above 
address.

Designation of Critical Habitat Provides Little Additional Protection 
to Species

    In 30 years of implementing the Act, the Service has found that the 
designation of statutory critical habitat provides little additional 
protection to most listed species, while consuming significant amounts 
of available conservation resources. The Service's

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present system for designating critical habitat has evolved since its 
original statutory prescription (into a process that provides little 
real conservation benefit, is driven by litigation and the courts 
rather than biology, limits our ability to fully evaluate the science 
involved, consumes enormous agency resources, and imposes huge social 
and economic costs). The Service believes that additional agency 
discretion would allow our focus to return to those actions that 
provide the greatest benefit to the species most in need of protection.
    Attention to and protection of habitat is paramount to successful 
conservation actions. The role that designation of critical habitat 
plays in protecting habitat of listed species, however, is often 
misunderstood. As discussed in more detail below in the discussion of 
exclusions under ESA section 4(b)(2), there are significant limitations 
on the regulatory effect of designation under ESA section 7(a)(2). In 
brief, (1) designation provides additional protection to habitat only 
where there is a Federal nexus; (2) the protection is relevant only 
when, in the absence of designation, destruction or adverse 
modification of the critical habitat would in fact take place (in other 
words, other statutory or regulatory protections, policies, or other 
factors relevant to agency decision-making would not prevent the 
destruction or adverse modification); and (3) designation of critical 
habitat triggers the prohibition of destruction or adverse modification 
of that habitat, but it does not require specific actions to restore or 
improve habitat.
    Currently, only 473 species, or 37 percent of the 1,272 listed 
species in the U.S. under the jurisdiction of the Service, have 
designated critical habitat. We address the habitat needs of all 1,272 
listed species through conservation mechanisms such as listing, section 
7 consultations, the section 4 recovery planning process, the section 9 
protective prohibitions of unauthorized take, section 6 funding to the 
States, the section 10 incidental take permit process, and cooperative, 
nonregulatory efforts with private landowners. The Service believes 
that it is these measures that may make the difference between 
extinction and survival for many species.
    In considering exclusions of areas proposed for designation, we 
evaluated the benefits of designation in light of Gifford Pinchot Task 
Force v. United States Fish and Wildlife Service. In that case, the 
Ninth Circuit invalidated the Service's regulation defining 
``destruction or adverse modification of critical habitat.'' In 
response, on December 9, 2004, the Director issued guidance to be 
considered in making section 7 adverse modification determinations. 
This proposed critical habitat designation does not use the invalidated 
regulation in our consideration of the benefits of including areas in 
this final designation. The Service will carefully manage future 
consultations that analyze impacts to designated critical habitat, 
particularly those that appear to be resulting in an adverse 
modification determination. Such consultations will be reviewed by the 
Regional Office prior to finalizing to ensure that an adequate analysis 
has been conducted that is informed by the Director's guidance.
    On the other hand, to the extent that designation of critical 
habitat provides protection, that protection can come at significant 
social and economic cost. In addition, the mere administrative process 
of designation of critical habitat is expensive, time-consuming, and 
controversial. The current statutory framework of critical habitat, 
combined with past judicial interpretations of the statute, make 
critical habitat the subject of excessive litigation. As a result, 
critical habitat designations are driven by litigation and courts 
rather than biology, and made at a time and under a time frame that 
limits our ability to obtain and evaluate the scientific and other 
information required to make the designation most meaningful.
    In light of these circumstances, the Service believes that 
additional agency discretion would allow our focus to return to those 
actions that provide the greatest benefit to the species most in need 
of protection.

Procedural and Resource Difficulties in Designating Critical Habitat

    We have been inundated with lawsuits for our failure to designate 
critical habitat, and we face a growing number of lawsuits challenging 
critical habitat determinations once they are made. These lawsuits have 
subjected the Service to an ever-increasing series of court orders and 
court-approved settlement agreements, compliance with which now 
consumes nearly the entire listing program budget. This leaves the 
Service with little ability to prioritize its activities to direct 
scarce listing resources to the listing program actions with the most 
biologically urgent species conservation needs.
    The consequence of the critical habitat litigation activity is that 
limited listing funds are used to defend active lawsuits, to respond to 
Notices of Intent (NOIs) to sue relative to critical habitat, and to 
comply with the growing number of adverse court orders. As a result, 
listing petition responses, the Service's own proposals to list 
critically imperiled species, and final listing determinations on 
existing proposals are all significantly delayed.
    The accelerated schedules of court-ordered designations have left 
the Service with limited ability to provide for public participation or 
to ensure a defect-free rulemaking process before making decisions on 
listing and critical habitat proposals, due to the risks associated 
with noncompliance with judicially imposed deadlines. This in turn 
fosters a second round of litigation in which those who fear adverse 
impacts from critical habitat designations challenge those 
designations. The cycle of litigation appears endless, and is very 
expensive, thus diverting resources from conservation actions that may 
provide relatively more benefit to imperiled species.
    The costs resulting from the designation include legal costs, the 
cost of preparation and publication of the designation, the analysis of 
the economic effects and the cost of requesting and responding to 
public comment, and in some cases the costs of compliance with the 
National Environmental Policy Act (NEPA). These costs, which are not 
required for many other conservation actions, directly reduce the funds 
available for direct and tangible conservation actions.

Background

    It is our intent to discuss only those topics directly relevant to 
the designation of critical habitat in this proposed rule. For more 
information on Cirsium hydrophilum var. hydrophilum and Cordylanthus 
mollis ssp. mollis, refer to the final listing rule published in the 
Federal Register on November 20, 1997 (62 FR 61916).
    Tidal marshes in the San Francisco Bay Estuary have been 
significantly affected by habitat loss, fragmentation, and degradation 
over the last 200 years. San Pablo Bay and Suisun Bay have seen 70 and 
79 percent reductions in tidal marshes, respectively (San Francisco 
Estuary Institute (SFEI) 1998; Goals Project 1999). A large portion of 
historic tidal marshes in San Pablo Bay are diked and managed for 
agricultural production and livestock grazing. In Suisun Bay, most 
historic tidal marshes are diked and managed for wildlife, especially 
waterfowl. Suisun Marsh, the largest managed marsh in the estuary, is 
primarily used to provide wintering feeding habitat for migrating 
waterfowl (Suisun Ecological Workgroup 2001). These historic reductions 
in turn have

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affected the extent and composition of tidal marsh plant communities. 
As a result, many native halophytic (salt-tolerant) plants are 
exceedingly rare in tidal marshes within the estuary (Goals Project 
2000).

Cirsium hydrophilum var. hydrophilum

    The original description of Cirsium hydrophilum var. hydrophilum by 
Greene (1892) indicated that the subspecies was ``[v]ery common in the 
brackish marshes of Suisun Bay, California, where it grows within reach 
of tide water.'' Later references (Jepson 1901; Munz and Keck 1968) 
indicate that the subspecies was found in marshes or brackish marshes 
about Suisun Bay, but these references lacked detailed information on 
its distribution. Herbarium records at the University of California at 
Davis (UCD) (2005) from 1863 to 1974 indicate that the subspecies 
occurred in the Suisun Marsh area. This information suggests that the 
subspecies probably did not occur outside of the Suisun Bay area in 
Solano County.
    By 1975, Cirsium hydrophilum var. hydrophilum was thought to have 
been extirpated from Suisun Bay because the subspecies had not been 
seen for about 15 years. The subspecies was later rediscovered in 1989 
in Suisun Marsh (California Native Plant Society 2001). Populations 
(groups of plants based on occurrence records or reports) were 
discovered and described during further field surveys in 1991 and 1992 
at Rush Ranch (Solano Land Trust) and Peytonia Slough Ecological 
Reserve, respectively (California Department of Water Resources (CDWR) 
1993 and 1994). The subspecies' current distribution is limited to 
scattered colonies within relict undiked high tidal marshes (fully 
tidal, emergent estuarine marshes) at Rush Ranch, the Joice Island 
portion of Grizzly Island Wildlife Area, and Peytonia Slough Ecological 
Reserve in Solano County (L. C. Lee and Associates (LCLA) 2003, 
California Natural Diversity Database (CNDDB) 2005). These marshes 
occur from the mean high water mark to the marsh'upland ecotone 
(transition zone) (Goals Project 1999 and 2000).
    There are two areas known to currently support Cirsium hydrophilum 
var. hydrophilum (CDWR 1996; CNDDB 2005). These areas are the Rush 
Ranch/Grizzly Island Wildlife Area and the Peytonia Slough Ecological 
Reserve. Field surveys have found several thousand individual plants at 
Rush Ranch and much smaller numbers at Grizzly Island Wildlife Area 
(CNDDB 2005; LCLA 2003; CNDDB 2005). The population at the Peytonia 
Slough Ecological Reserve declined to a single individual plant 
observed in 1996 (CDWR 1996).
    Cirsium hydrophilum var. hydrophilum colonies at Rush Ranch/Grizzly 
Island Wildlife Area are associated with tidal marsh habitats that are 
hydrologically connected to the First and Second Mallard Branches, 
Suisun Slough, and Cutoff Slough (CDWR 1996; LCLA 2003). The population 
at the Peytonia Slough Ecological Reserve is associated with tidal 
marsh habitat hydrologically connected to Peytonia Slough.

Cordylanthus mollis ssp. mollis

    Cordylanthus mollis ssp. mollis is endemic to the San Pablo Bay and 
Suisun Bay area. The subspecies was historically found in high tidal 
marshes along the Petaluma River and Napa River through the Carquinez 
Strait to Suisun Bay and the San Joaquin-Sacramento River Delta in 
Marin, Sonoma, Napa, Solano, Contra Costa, and Sacramento Counties 
(Gray 1867; Munz and Keck 1959; Chuang and Heckard 1973; Rae 1978; UCD 
2005). The subspecies is currently found in widely scattered 
populations from Point Pinole and Fagan Slough marsh through the 
Carquinez Strait to Suisun Bay in Napa, Solano, and Contra Costa 
Counties (Stromberg and Villasenor 1986; Ruygt 1994; CNDDB 2005). C. 
mollis ssp. mollis has been listed as rare within its range since July 
1979 under the Native Plant Protection Act of 1977 and California 
Endangered Species Act of 1984 (California Department of Fish and Game 
(CDFG) 2006).
    The largest populations of Cordylanthus mollis ssp. mollis are 
found in Suisun Marsh (Rush Ranch, the Joice Island portion of Grizzly 
Island Wildlife Area, and Hill Slough Wildlife Area in Solano County), 
Fagan Slough Marsh (Fagan Marsh Ecological Reserve in Napa County), 
Southampton Marsh (Benicia State Recreation Area in Solano County), and 
the Concord Naval Weapons Station (CNWS) in Contra Costa County 
(Stromberg and Villasenor 1986; Ruygt 1994; Rejmankova and Grewell 
2000; CNDDB 2005). There are eight occurrences considered extirpated 
(Antioch Bridge; Beldons Landing, Bentley Wharf, Cullinan Ranch, Mare 
Island, Martinez, Petaluma Marsh, and San Antonio Creek Marsh) in 
Marin, Sonoma, Napa, Solano, Contra Costa, and Sacramento Counties 
because of habitat loss or degradation, or the inability of finding the 
subspecies after extensive and repeated field surveys (Ruygt 1994; 
CNDDB 2005).
    Cordylanthus mollis ssp. mollis has a high degree of population 
size variability from year-to-year at any given location. Periodic 
field surveys have shown that most extant locations have high densities 
of plants numbering in the thousands to the tens of thousands within 
small, localized populations (Stromberg and Villasenor 1986; Ruygt 
1994; CNDDB 2005). Other locations consist of widely scattered 
populations with few individual plants. Some populations may fail to 
appear entirely for several years and reappear later in the same 
general area. The reasons for the population fluctuations are not well 
known.

Suisun Marsh Management Strategies

    In evaluating areas to propose as critical habitat for Cirsium 
hydrophilum var. hydrophilum and Cordylanthus mollis ssp. mollis, we 
recognized that Federal, State, and local conservation planning efforts 
in the Suisun Marsh are ongoing. This proposed designation includes all 
habitat in the Suisun Marsh for the two subspecies that meets our 
criteria for identifying the essential features for the two subspecies, 
including lands that are a part of these planning efforts. We seek 
public comment about whether the developing Suisun Marsh Habitat 
Management, Preservation, and Restoration Plan and the previously 
developed Suisun Marsh Protection Plan would provide an alternative to 
a critical habitat designation that provides special management for 
those physical and biological characteristics that are essential to the 
conservation of the subspecies. The potential result of the plan would 
be to avoid critical habitat designation because the special management 
or protection would not be necessary or the benefits of excluding the 
areas as critical habitat outweigh the benefits of inclusion. One 
reason the benefits of exclusion could outweigh those of inclusion is 
that designating a particular area might prevent the implementation of 
a local plan which would otherwise provide a greater benefit to the 
species.
    It is the Service's goal to identify and support innovative 
cooperative conservation approaches that have a similar or greater 
likelihood of providing for the conservation of listed subspecies when 
compared to traditional regulatory approaches such as designation of 
critical habitat. In our determination of whether habitat is in need of 
``special management or protection,'' the Service will evaluate the 
Suisun Marsh Habitat Management, Preservation, and Restoration Plan and 
the previously developed Suisun Marsh Protection Plan to determine 
whether their implementation would provide a

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similar or greater level of conservation benefits to the Cirsium 
hydrophilum var. hydrophilum and Cordylanthus mollis ssp. mollis when 
compared to a final designation of critical habitat. The two management 
strategies are outlined below.

The Suisun Marsh Protection Plan and the Suisun Marsh Preservation Act

    The Suisun Marsh Protection Plan of 1976 (SMPP) establishes a 
``primary management area'' in Suisun Marsh that encompasses the entire 
range of Cirsium hydrophilum var. hydrophilum, and also includes the 
areas we propose as critical habitat units 2 and 4 for Cordylanthus 
mollis ssp. mollis (SFBCDC 2006, 1976). The Plan recommends that areas 
within the primary management area ``should be protected and managed to 
enhance the quality and diversity of the habitats' (SFBCDC 2006). It 
further recommends that ``[t]he tidal marshes in the primary management 
area should be preserved'' and that ``[w]here feasible historic marshes 
should be returned to wetland status.'' The SMPP was incorporated into 
State law by the Suisun Marsh Preservation Act of 1977 (SMPA), which 
utilizes a State-level permitting process and a county-level protection 
program to prevent development in the marsh that is inconsistent with 
the SMPP (SFBCDC 2005).

Suisun Marsh Habitat Management, Preservation, and Restoration Plan

    The Suisun Marsh Habitat Management, Preservation, and Restoration 
Plan (SMHMP) is being developed by the Suisun Marsh Charter Group 
(Charter Group), a collaborative effort among of Federal, State and 
local agencies with primary responsibility for actions in the Suisun 
Marsh. The Charter Group principal agencies are the Service, USBR, 
CDFG, DWR, Suisun Resource Conservation District, California Bay--Delta 
Authority, and National Oceanic and Atmospheric Administration's 
National Marine Fisheries Service. Additional public entities 
participating in the Charter Group include: U.S. Army Corps of 
Engineers (USACE), San Francisco Bay Conservation and Development 
Commission, and San Francisco Bay--Delta Science Consortium. The 
Service and USBR are participating as National Environmental Policy Act 
(NEPA) co-lead Federal agencies, and the CDFG is the lead California 
Environmental Quality Act (CEQA) State agency, for the development of 
the Programmatic Environmental Impact Statement/Report (PEIS/R). These 
lead agencies will oversee the environmental review process for the 
SMHMP.
    The Charter Group was formed in 2001 to resolve issues of amending 
the Suisun Marsh Preservation Agreement (SMPA), obtain a Regional 
General Permit from the USACE, implement the Suisun Marsh Levee 
Program, and recover threatened and endangered species. The broader 
purpose of the Charter Group was to develop and agree on a long-term 
implementation plan for the Suisun Marsh consistent with, and in the 
context of, the CALFED Bay--Delta Program (a consortium of State and 
Federal agencies working cooperatively to improve the quality and 
reliability of California's water supplies while restoring the Bay--
Delta ecosystem). The mission of the CALFED Bay--Delta Program is to 
develop and implement a long-term comprehensive plan that will restore 
ecological health and improve water management for beneficial uses of 
the Bay-Delta System.
    The Charter Group has been charged with developing a regional plan 
that would outline the actions needed in Suisun Marsh to preserve and 
enhance managed seasonal wetlands, restore tidal marsh habitat, 
implement a comprehensive levee protection and improvement program, and 
protect ecosystem and drinking water quality. The proposed SMHMP would 
be consistent with the goals and objectives of the Bay--Delta Program, 
and balance them with SMPA, Federal and State Endangered Species Acts, 
and other management and restoration programs within the Suisun Marsh 
in a manner responsive to the concerns of all stakeholders, and based 
upon voluntary participation by private landowners. The proposed SMHMP 
also would provide for simultaneous protection and enhancement of: (1) 
The Pacific Flyway and existing wildlife values in managed wetlands; 
(2) threatened and endangered species; (3) tidal marshes and other 
ecosystems; and (4) water quality, including, but not limited to, the 
maintenance and improvement of levees. The SMHMP has seven goals:

     Goal 1, Ecological Processes: Rehabilitate natural 
processes where feasible in the Suisun Marsh to more fully support, 
with minimal human intervention, natural aquatic and associated 
terrestrial biotic communities and habitats, in ways that favor 
native species of those communities, with a particular interest in 
waterfowl and sensitive species.
     Goal 2, Habitats: Protect, restore, and enhance habitat 
types where feasible in the Suisun Marsh for ecological and public 
values, such as supporting species and biotic communities, 
ecological processes, recreation, scientific research, and 
aesthetics.
     Goal 3, Levee System Integrity: Provide long-term 
protection for multiple Suisun Marsh resources by maintaining and 
improving the integrity of the Suisun Marsh levee system.
     Goal 4, Non-Native Species: Prevent the establishment 
of additional non-native species and reduce the negative ecological 
and economic impact of established non-native species in the Suisun 
Marsh.
     Goal 5, Water and Sediment Quality: Maintain or improve 
water and sediment quality conditions to provide good quality water 
for all beneficial uses and fully support healthy and diverse 
aquatic ecosystems in the Suisun Marsh; and to eliminate, to the 
extent possible, toxic impacts to aquatic organisms, wildlife, and 
people.
     Goal 6, Public Use and Waterfowl Hunting: Maintain the 
heritage of waterfowl hunting and increase the surrounding 
communities' awareness of the ecological values of the Suisun Marsh.
     Goal 7, Long-Term Funding, Plan Implementation, and 
Regulatory Reliability and Efficiency: Develop and implement a plan 
that: (1) Addresses long-term funding, (2) creates an efficient and 
reliable regulatory climate, (3) promotes effective management 
practices, and (4) improves coordination of activities among 
agencies within and adjacent to the Suisun Marsh.

    The Charter Group is committed to a planning process, consistent 
with the CALFED Record of Decision that includes strong local 
involvement, is integrated with other programs, uses the best available 
scientific and commercial information, and is open and transparent. 
Public scoping has been completed for the PEIS/R. The Service's 
External Affairs Program is conducting ongoing public outreach through 
the publication of a newsletter. When the Draft PEIS/R is completed, it 
will be available for public review and comment. The SMHMP is in the 
final stages of development, and it is anticipated that the Draft PEIS/
R will be available for public review and comment in the fall of 2006 
before the final designation of critical habitat. Once the SMHMP has 
been finalized and the Draft PEIS/R is available to the public, we will 
reopen the comment period on this proposal to solicit comments. We 
recognize that the public is not able to comment on specific aspects of 
the plan without it being available for review, but we would like to 
solicit public comments as described below.

Public Comments Solicited

    In addition to the analysis conducted when assessing potential 
economic impacts of the Cirsium hydrophilum var. hydrophilum and 
Cordylanthus mollis ssp. mollis critical habitat designation, the 
Secretary will evaluate other considerations as part of the 4(b)(2) 
exclusion process. As part of the

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Secretary's deliberative process, the Service identifies the benefits 
of inclusion and exclusion of various areas.
    The Service will evaluate whether the regulatory benefits of 
designation of critical habitat in the Suisun Marsh for the Cirsium 
hydrophilum var. hydrophilum and Cordylanthus mollis ssp. mollis 
outweigh the conservation benefits of implementation of the SMHMP. In 
this proposed rule, we are soliciting public comment on the relative 
merits of a critical habitat designation when compared to 
implementation of the SMHMP. We are particularly interested in public 
comment on the following issues:

     What is necessary to ensure the conservation of the 
Suisun thistle and soft bird's-beak with regard to private lands in 
the Suisun Marsh;
     Whether areas preserved by the Suisun Marsh Protection 
Plan or covered under the SMHMP should be designated as critical 
habitat and the degree to which a critical habitat designation would 
confer conservation benefits on the Cirsium hydrophilum var. 
hydrophilum and Cordylanthus mollis ssp. mollis when compared to the 
likely benefits of the alternative SMHMP;
     The degree to which the designation or the SMHMP would 
educate members of the public such that conservation efforts would 
be enhanced;
     The degree to which a critical habitat designation or 
the SMHMP would have a positive, neutral, or negative impact on 
voluntary conservation efforts on privately owned lands;
     Whether the tidal restoration and habitat protection 
goals proposed in the upcoming SMHMP will protect the habitat 
sufficiently; and
     Whether a critical habitat designation of private lands 
already occupied by the Cirsium hydrophilum var. hydrophilum and 
Cordylanthus mollis ssp. mollis and subject to the regulatory 
provisions of the Act will provide additional regulatory 
conservation benefits to accrue on those lands and whether 
traditional methods of regulation under the Act (for example, 
section 7 consultation with the USACE) are adequate to provide for 
the long-term conservation of the C. hydrophilum var. hydrophilum 
and C. mollis ssp. mollis on private lands in the Suisun Marsh.

    The Service will evaluate information received on these and other 
issues when making a decision concerning the final designation of 
critical habitat. Comments on the SMHMP may be sent to the Field 
Supervisor of the Sacramento Fish and Wildlife Service (see ADDRESSES 
section). Any economic exclusions would be predicated on the results of 
the economic analysis.

Previous Federal Actions

    Cirsium hydrophilum var. hydrophilum and Cordylanthus mollis ssp. 
mollis were listed as endangered in the final listing rule published in 
the Federal Register on November 20, 1997 (62 FR 61916). In the final 
listing rule for the two subspecies, we determined that the designation 
of critical habitat was not prudent because that the designation would 
not be beneficial to the conservation of the two subspecies.
    On November 17, 2003, the Center for Conservation Biology and 
others filed a lawsuit in the Northern District of California against 
the Secretary of the Interior, challenging the not prudent 
determination of critical habitat for the two subspecies (Center for 
Biological Diversity, et al. v. Gale Norton, Secretary of the 
Department of the Interior, et al., CV 03-5126-CW). On June 14, 2004, 
the U.S. District Court Judge signed an Order granting a stipulated 
settlement agreement between the two parties. The Service agreed to 
propose critical habitat for the two plant subspecies on or before 
April 1, 2006, and finalize the designation on or before April 1, 2007. 
For more information on previous Federal actions concerning Cirsium 
hydrophilum var. hydrophilum and Cordylanthus mollis ssp. mollis, refer 
to the final listing rule published in the Federal Register (62 FR 
61916) on November 20, 1997.

Critical Habitat

    Critical habitat is defined in section 3 of the Act as--(i) the 
specific areas within the geographical area occupied by a species, at 
the time it is listed in accordance with the Act, on which are found 
those physical or biological features (I) essential to the conservation 
of the species and (II) that may require special management 
considerations or protection; and (ii) specific areas outside the 
geographical area occupied by a species at the time it is listed, upon 
a determination that such areas are essential for the conservation of 
the species. Conservation, as defined under section 3 of the Act, means 
to use and the use of all methods and procedures which are necessary to 
bring any endangered species or threatened species to the point at 
which the measures provided pursuant to the Act are no longer 
necessary. Such methods and procedures include, but are not limited to, 
all activities associated with scientific resources management such as 
research, census, law enforcement, habitat acquisition and maintenance, 
propagation, live trapping, and transplantation, and, in the 
extraordinary case where population pressures within a given ecosystem 
cannot be otherwise relieved, may include regulated taking.
    Critical habitat receives protection under section 7 of the Act 
through the prohibition against destruction or adverse modification of 
critical habitat with regard to actions carried out, funded, or 
authorized by a Federal agency. Section 7 requires consultation on 
Federal actions that are likely to result in the destruction or adverse 
modification of critical habitat. The designation of critical habitat 
does not affect land ownership or establish a refuge, wilderness, 
reserve, preserve, or other conservation area. Such designation does 
not allow government or public access to private lands. Section 7 is a 
purely protective measure and does not require implementation of 
restoration, recovery, or enhancement measures.
    To be included in a critical habitat designation, the habitat 
within the area occupied by the species must first have features that 
are essential to the conservation of the species. Critical habitat 
designations identify, to the extent known using the best scientific 
data available, habitat areas that provide essential life cycle needs 
of the species (areas on which are found the primary constituent 
elements, as defined at 50 CFR 424.12(b)).
    Habitat occupied at the time of listing may be included in critical 
habitat only if the essential features thereon may require special 
management or protection. Thus, we do not include areas where existing 
management is sufficient to conserve the species. As discussed below, 
such areas may also be excluded from critical habitat pursuant to 
section 4(b)(2). Accordingly, when the best available scientific data 
do not demonstrate that the conservation needs of the species so 
require, we will not designate critical habitat in areas outside the 
geographical area occupied by the species at the time of listing. An 
area currently occupied by the species but was not known to be occupied 
at the time of listing will likely, but not always, be essential to the 
conservation of the species and, therefore, typically included in the 
critical habitat designation.
    The Service's Policy on Information Standards Under the Endangered 
Species Act, published in the Federal Register on July 1, 1994 (59 FR 
34271), and Section 515 of the Treasury and General Government 
Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658) 
and the associated Information Quality Guidelines issued by the 
Service, provide criteria, establish procedures, and provide guidance 
to ensure that decisions made by the Service represent the best 
scientific data available. They require

[[Page 18461]]

Service biologists to the extent consistent with the Act and with the 
use of the best scientific data available, to use primary and original 
sources of information as the basis for recommendations to designate 
critical habitat. When determining which areas are critical habitat, a 
primary source of information is generally the listing package for the 
species. Additional information sources include the recovery plan for 
the species, articles in peer-reviewed journals, conservation plans 
developed by States and counties, scientific status surveys and 
studies, biological assessments, or other unpublished materials and 
expert opinion or personal knowledge. All information is used in 
accordance with the provisions of Section 515 of the Treasury and 
General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 
106-554; H.R. 5658) and the associated Information Quality Guidelines 
issued by the Service.
    Section 4 of the Act requires that we designate critical habitat on 
the basis of the best scientific data available. Habitat is often 
dynamic, and species may move from one area to another over time. 
Furthermore, we recognize that designation of critical habitat may not 
include all of the habitat areas that may eventually be determined to 
be necessary for the recovery of the species. For these reasons, 
critical habitat designations do not signal that habitat outside the 
designation is unimportant or may not be required for recovery.
    Areas that support populations, but are outside the critical 
habitat designation, will continue to be subject to conservation 
actions implemented under section 7(a)(1) of the Act and to the 
regulatory protections afforded by the section 7(a)(2) jeopardy 
standard, as determined on the basis of the best available information 
at the time of the action. Federally funded or permitted projects 
affecting listed species outside their designated critical habitat 
areas may still result in jeopardy findings in some cases. Similarly, 
critical habitat designations made on the basis of the best available 
information at the time of designation will not control the direction 
and substance of future recovery plans, habitat conservation plans, or 
other species conservation planning efforts if new information 
available to these planning efforts calls for a different outcome.

Methods

    As required by section 4(b)(2) of the Act, we used the best 
scientific data available in determining areas that contain the 
features that are essential to the conservation of Cirsium hydrophilum 
var. hydrophilum and Cordylanthus mollis ssp. mollis. The following 
geospatial, tabular data sets were used in determining critical 
habitat: occurrence data for C. hydrophilum var. hydrophilum and C. 
mollis ssp. mollis (CNDDB 2005); historic and modern habitats of the 
San Francisco Bay Estuary (SFEI 1998); data gathered for the 
development of the draft recovery plan (Service 2005); Contra Costa, 
Napa, and Solano County soil survey data (Natural Resources and 
Conservation Service (NRCS) 2005c); vegetation mapping and tidal marsh 
data for Suisun Marsh (Vaghti and Keeler-Wolf 2004a and 2004b); 
National Wetlands Inventory data for Contra Costa, Napa, and Solano 
Counties (National Wetlands Inventory (NWI) 2005); black and white 
1:24,000 scale digital orthophoto quarter quadrangles (U.S. Geological 
Survey (USGS) dated June/July 1993); Teale data for California wetlands 
and hydrography (California Spatial Information Library 2005); color 
mosaic 1:9,600 scale digital aerial photographs for Suisun Bay (dated 
June 16, 2003) (CDFG 2005c); and 1:24,000 scale digital raster graphics 
of USGS topographic quadrangles. Land ownership was determined from 
geospatial data sets associated with 2003 parcel data from Contra Costa 
and Napa Counties (SFWO 2005), 2005 parcel data for Suisun Marsh (CDFG 
2005a), and boundary data for CDFG lands (CDFG 2005b).
    Additional information was provided by Brenda Grewell (ecologist 
with the U.S. Department of Agriculture (USDA), Agricultural Research 
Service at the University of California at Davis) and staff from CDFG, 
California Department of Parks and Recreation (CDPR), East Bay Regional 
Park District (EBRPD), Solano Land Trust, and the U.S. Department of 
the Navy (USDN). We also conducted local site visits at Rush Ranch, 
Hill Slough and Grizzly Island Wildlife Areas, Peytonia Slough 
Ecological Reserve, Southampton Marsh, Point Pinole Regional Shoreline, 
and McAvoy Boat Harbor.
    We have reviewed available information that pertains to the habitat 
requirements of Cirsium hydrophilum var. hydrophilum and Cordylanthus 
mollis ssp. mollis. There is limited information on habitat 
requirements for these subspecies, but the primary informational 
sources are (1) CNDDB (2005); (2) CDWR (1993, 1994, 1996, 1999, and 
2001) correspondence and reports for Suisun Marsh; (3) Baylands 
Ecosystem Goals Project (1999 and 2000); and (4) information gathered 
for the development of the draft recovery plan for the subspecies 
(Service 2005). We reviewed scientific studies and survey reports for 
C. hydrophilum var. hydrophilum (LCLA 2003) and C. mollis ssp. mollis 
(Stromberg and Villasenor 1986; Ruygt 1994; Rejmankova and Grewell 
2000; Grewell et al. 2003; Grewell 2004; EBRPD 2005). A variety of 
other non-peer and peer-reviewed articles were reviewed for background 
information on wetland ecology and hydrology, plant ecology and 
biology, and historical accounts of the San Francisco Bay and Joaquin-
Sacramento River Delta.

Primary Constituent Elements

    In accordance with section 3(5)(A)(i) of the Act and regulations at 
50 CFR 424.12, in determining which areas to propose as critical 
habitat, we are required to base critical habitat determinations on the 
best scientific and commercial data available and to consider those 
physical and biological features (primary constituent elements (PCEs)) 
that are essential to the conservation of the subspecies, and that may 
require special management considerations and protection. These 
include, but are not limited to, space for individual and population 
growth and for normal behavior; food, water, air, light, minerals, or 
other nutritional or physiological requirements; cover or shelter; 
sites for breeding, reproduction, and rearing (or development) of 
offspring; and habitats that are protected from disturbance or are 
representative of the historic geographical and ecological 
distributions of a species.

Space for Individual and Population Growth and Normal Behavior

    The San Francisco Bay Estuary is the largest contiguous tidal marsh 
system on the Pacific Coast of North America. The estuary undergoes two 
daily tidal cycles with large differences between successive high and 
low tidal cycles. The primary source of fresh water entering the 
estuary is through the San Joaquin-Sacramento River systems (Pestrong 
1972; Conomos et al. 1985). Saltwater and seasonal freshwater inflows 
into the estuary affect salinity levels, sediment deposition, tidal 
flushing, and the vertical extent of marsh vegetation in tidal marshes 
(Purer 1942; Josselyn 1983).
    The depth, duration, and frequency of tidal flows directly affect 
tidal marsh channel networks and distribution of plant communities. 
Under natural tidal regimes, channels develop and migrate through 
erosion and deposition processes (such as channel undercutting, bank 
slumping, and sedimentation) during daily flood and

[[Page 18462]]

ebb flows and seasonal storm events (Pestrong 1965 and 1972; Garofalo 
1980). These networks delineate the degree of tidal flooding based on 
the width, depth, and elevation of existing channels. The intensity of 
tidal events controls the level of tidal flushing within marshes. 
Flushing actions as well as seasonal freshwater inflows help to 
moderate soil and ground water salinity on a spatial and temporal basis 
(Purer 1942; Sanderson 1998; Sanderson et al. 2000 and 2001). These 
natural processes acting together impose a strong influence on plant 
germination and growth in tidal marshes (Vine and Snow 1984; DeLaune et 
al. 1987; Pennings and Callaway 1992; Konisky and Burdick 2004).
    Significant changes can occur in tidal marshes, above normal 
seasonal conditions, to affect plant distributions when natural tidal 
hydrology is artificially modified by construction of tide gates, 
mosquito abatement ditches, levees, or other water control structures 
to restrict its full tidal range. These include changes to soil 
salinity, chemistry, and aeration (for example, leading to soil 
subsidence and compaction); lowering of water tables; reductions in 
sedimentation rates and vertical marsh accretion; and increases in 
organic materials (Mahall and Park 1976; Balling and Resh 1983; 
Anisfeld and Benoit 1997; Burdick et al. 1997; Portnoy and Giblin 1997; 
Bryant and Chabreck 1998; Kuhn et al. 1999; Portnoy 1999; Goals Project 
2000; Reed 2002). This is often followed by a change in the 
vegetational composition from typical native halophytic marsh plants to 
less salt-tolerant native and non-native plants (Roman et al. 1984; 
Goals Project 2000). These changes generally fail to support rare tidal 
marsh plants such as Cirsium hydrophilum var. hydrophilum and 
Cordylanthus mollis ssp. mollis (Goals Project 2000) and therefore, 
only those areas that have been shown to support populations of the two 
subspecies or shown to support the features identified as essential for 
the two subspecies have been proposed for designation.

Landscape Ecology of Cirsium hydrophilum var. hydrophilum

    Most Cirsium hydrophilum var. hydrophilum occurrences are found 
along the banks of canals or ditches, within 50 to 100 feet (15.2 to 
30.5 meters (m)) of the high water mark of natural tidal channels, and 
on tidal floodplains within tidal marshes (CDWR 1993; LCLA 2003; CNDDB 
2005). Occurrences in these areas may result from tidal inundations 
lowering soil and ground water salinity (tidal flushing) producing a 
less stressful environment for plant establishment (Balling and Resh 
1983; Sanderson 1998). The subspecies is also most often found in 
regularly flooded and permanently saturated habitats (LCLA 2003; NWI 
2005). Few occurrences are located in seasonally flooded or saturated 
habitats (LCLA 2003). The subspecies does not appear to thrive in diked 
wetlands or along narrow fringe high tidal marshes on the outboard side 
of levees (CDWR 1994; Goals Project 2000). These areas were not 
considered to be capable of sustaining or supporting populations of the 
subspecies and have not been included in the proposed designation.
    Common native plant associates of Cirsium hydrophilum var. 
hydrophilum include Argentina egedii ssp. egedii (Pacific silverweed), 
Atriplex prostrate (triangle orache), Cicuta maculate var. bolanderi 
(spotted water hemlock), Distichlis spicata (inland saltgrass), 
Euthamia occidentalis (western goldentop), Grindelia stricta (Oregon 
gumweed), Jaumea carnosa (gray marsh jaumea), Juncus balticus (Baltic 
rush), Salicornia virginica (Virginia glasswort), Schoenoplectus 
pungens var. pungens (common threesquare), and Senecio hydrophilus 
(water ragwort). Common non-native plant associates include Apium 
graveolens (wild celery), Lepidium latifolium (broadleaved 
peppergrass), and Rumex crispus (curly dock) (CDWR 1994; LCLA 2003; 
plant names referenced from NRCS 2005b). Lepidium latifolium is of 
special concern since it forms large monotypic patches that displace 
native marsh vegetation (Renz 2000). LCLA (2003) observed that the five 
most dominate associates at Rush Ranch, based on canopy coverage in 
sample plots, were Argentina egedii ssp. egedii, Schoenoplectus pungens 
var. pungens, Juncus balticus, Lepidium latifolium, and Grindelia 
stricta.

Landscape Ecology of Cordylanthus mollis ssp. mollis

    Most extant occurrences of Cordylanthus mollis ssp. mollis are 
located in high tidal marshes that receive full tidal inundations (SFEI 
1998; CNDDB 2005). Narrow fringe high tidal marshes on the outboard 
side of levees do not appear to support the subspecies (CDWR 1994; 
Goals Project 2000). Fully tidal marshes at Hill Slough Marsh, Rush 
Ranch, the Joice Island portion of Grizzly Island Wildlife Area, 
Southampton Marsh, Fagan Slough Marsh, McAvoy Boat Harbor, and Point 
Pinole Shoreline account for approximately 80 percent of the total 
mapped occurrences from CNDDB (2005). Non-specific occurrences include 
data sources with imprecise location information. These data are mapped 
as circles of varying radii based on data reliability (Bittman 2001). 
There were nine non-specific C. mollis ssp. mollis occurrences (Antioch 
Bridge, Bentley Wharf, Cullinan Ranch, Cutting Wharf, Mare Island, 
Martinez, McAvoy Boat Harbor, Petaluma Marsh, and San Antonio Creek 
Marsh) that were mapped with radii of 0.1 to 1 mile (0.16 to 1.6 
kilometers) (CNDDB 2005).
    Specific occurrences of Cordylanthus mollis ssp. mollis in muted 
high tidal marshes (marshes with reduced tidal range due to physical 
impediments (Goals Project 1999, page 79)) are found on the CNWS and a 
small area adjacent to the CNWS just north of the General Chemical 
plant along the Contra Costa shoreline. They account for approximately 
6 percent of all specific occurrences.
    Diked and managed marshes account for approximately 14 percent of 
all specific Cordylanthus mollis ssp. mollis occurrences. These marshes 
are located in the eastern portion of Suisun Marsh and around the 
perimeter of high tidal areas at Hill Slough and Fagan Slough marshes. 
The occurrence of C. mollis ssp. mollis populations in diked and 
managed marshes may likely be a result of dormant seed bank(s) and 
associated marsh conditions that still promote their establishment. 
However, future land use and management activities in these marshes may 
rapidly alter marsh conditions to further restrict or exclude the 
subspecies from the local plant community (Goals Project 1999 and 
2000).
    Populations of Cordylanthus mollis ssp. mollis typically occur 
above mean high water to the marsh-upland ecotone (Ruygt 1994; CDWR 
1999; Goals Project 1999). Most subspecies occurrences are found in 
regularly flooded and permanently saturated habitats (NWI 2005). 
Current populations are most often found in mixed halophytic plant 
communities with an average canopy height equal to or less than 20.5 
inches (in) (52 centimeters (cm)) (Grewell 2003). Tidal events are 
important for regulating tidal marsh plant communities and may be a 
critical factor in regulating the hemiparasitic life cycle of the 
subspecies (Ruygt 1994; Grewell et al. 2003).
    Cordylanthus mollis ssp. mollis establishes fragile parasitic root 
connections to their host plants by means of a specialized structure 
called a haustorium (Chuang and Heckard 1971; Grewell et al. 2003). 
These connections produce an extensive network of intertwined roots 
that provide the subspecies with part of its

[[Page 18463]]

water and nutritional requirements to augment its growth. C. mollis 
ssp. mollis does not appear to have a specific host plant preference 
(Grewell 2004). Seedlings will attach to a wide range of host plants, 
but not all plants are suitable hosts. Non-native winter annuals such 
as Hainardia cylindrical (barbgrass) and Polypogon monspeliensis 
(annual rabbitsfoot grass) or native winter annuals such as Juncus 
bufonius (toad rush) are not suitable hosts since they typically die 
before C. mollis ssp. mollis can flower and produce seeds (Grewell 2003 
and 2004). Known suitable hosts include Distichlis spicata (salt 
grass), Salicornia virginica (pickleweed), and Jaumea carnosa (marsh 
jaumea) (Grewell 2003 and 2004). Seedlings suffer increased mortality 
when they germinate near unsuitable hosts or in habitats with a low 
availability of suitable hosts (Grewell 2004).
    Common native plant associates of Cordylanthus mollis ssp. mollis 
include Atriplex prostrate, Cuscuta salina (saltmarsh dodder), 
Distichlis spicata, Jaumea carnosa, Limonium californicum (California 
sealavender), Plantago maritima (goose tongue), Salicornia virginica, 
Symphyotrichum expansum (southwestern annual saltmarsh aster), and 
Triglochin maritimum (seaside arrowgrass). A common non-native plant 
associate is Polygonum arenastrum (oval-leaf knotweed) (Ruygt 1994; 
Grewell 2003; plant names referenced from NRCS 2005b). Cuscuta salina 
is the most common plant associate of C. mollis ssp. mollis throughout 
its range (Grewell 2003).

Soils

    Soil survey data (NRCS 2005c) for Contra Costa, Napa, and Solano 
Counties are delineated by soil map units (series). A soil map unit 
represents an area dominated by one or several types of soils (NRCS 
1995). Each map unit is named based on its taxonomic classification of 
the dominant soil(s). Boundaries between soil types are determined by 
field surveys and soil models, but may not be fixed, since individual 
soils merge into one another as their properties gradually change over 
the landscape. The degree of soil genesis is driven by natural and 
anthropogenic processes on a landscape level that may further alter 
soil properties over time (Buol et al. 1980).
    Occurrences of Cirsium hydrophilum var. hydrophilum and 
Cordylanthus mollis ssp. mollis used for soil area estimates only 
include populations that have a specific polygon mapping precision 
(CNDDB 2005). Approximately 92.4 percent (98.3 ac/39.8 ha) of C. 
hydrophilum var. hydrophilum occurrences are found on hydric soil 
series that are slightly to moderately saline within the first 3 feet 
(ft)(0.9 meters (m)) of soil depth (USDA 1993, page 194; NRCS (2005a, 
2005c, and 2005d)). C. mollis ssp. mollis occurrences are found on 
approximately 91.1 percent (480.7 ac/194.5 ha) of hydric soil series 
that are slightly to moderately saline within the first 3 ft (0.9 m) of 
soil depth (USDA 1993, page 194; NRCS (2005a , 2005c, and 2005d)).
    It is not known whether the respective soil series associated with 
occurrences of Cirsium hydrophilum var. hydrophilum and Cordylanthus 
mollis ssp. mollis are due to limited seed dispersal, colonization 
potential, plant competition, changes in tidal marsh regimes, specific 
edaphic requirements, or other potential factors (Ruygt 1994; LCLA 
2003; Service 2005). Additional studies are needed to determine how 
soils affect the distribution of these subspecies in tidal marshes.

Reproduction in Cirsium hydrophilum var. hydrophilum

    Cirsium hydrophilum var. hydrophilum is a perennial plant that dies 
after flowering and bearing seeds. Its vegetative period is usually 1 
year, but if small vegetative plant size or unfavorable environmental 
conditions delay flowering, a plant may grow back from its central root 
crown after the winter, and thereby live for more than a year. 
Flowering occurs throughout the summer during most years and continues 
through the production of ripe seed heads (Service 2005).
    Pollination ecology of Cirsium hydrophilum var. hydrophilum has not 
been studied to identify specific flower pollinators. Field 
observations at Rush Ranch indicate that several bee species may be 
important in pollinating the subspecies (LCLA 2003; Service 2005). The 
most common species observed gathering pollen at the ranch was the 
yellow-faced bumble bee (Bombus vosnesenskii) (LCLA 2003).
    The reproductive output of Cirsium hydrophilum var. hydrophilum has 
not been quantified for individual plants. Results from sample plot 
data at Rush Ranch indicated that 21 percent of the plants were 
reproductive flowering adults and the rest were either first or second 
year non-flowering individuals (LCLA 2003). Flowering plants may 
produce hundreds of seed heads. Seed heads observed in July of 2000 had 
three to five ripe seeds per head, but many of them contained aborted 
seeds or were found with insect larvae engaged in active seed predation 
(Service 2005). Plant-eating insects can significantly limit seed 
production and plant demography as seen in several other Cirsium 
species (Louda and Potvin 1995; Palmisano and Fox 1997; Louda and 
O'Brien 2002; Rand and Louda 2004; Louda et al. 2005; Rose et al. 
2005).
    Information on short and long distance seed dispersal for Cirsium 
hydrophilum var. hydrophilum is lacking. The subspecies usually has a 
plumed pappus (tufted appendage) attached to each mature seed to aid in 
wind dispersal; however, the plumed pappus may sometimes detach from 
the relatively thick-walled, heavy seeds before it disperses (Service 
2005). Studies on other species in the same family have shown that most 
plumed seeds are wind dispersed only a few meters (Sheldon and Burrows 
1973; McEvoy and Cox 1987; Klinkhamer et al. 1988; Wallace et al. 
2005). The extent of horizontal seed dispersal is affected in part by 
local topography and surrounding vegetation (Sheldon and Burrows 1973; 
McEvoy and Cox 1987; Wallace et al. 2005). Streams and tidal flows have 
been shown to be important dispersal mechanisms in Cirsium vinaceum 
(Sacramento Mountain thistle) and certain halophytic plants (Koutstaal 
et al. 1987; Huiskes et al. 1995; Craddock and Huenneke 1997).
    The presence of numerous small, discrete colonies of Cirsium 
hydrophilum var. hydrophilum as seen by LCLA (2003) at Rush Ranch 
suggests that the subspecies may have relatively local breeding micro-
habitats resulting in limited seed dispersal. However, the relatively 
tall stature of this subspecies, as compared to other associated tidal 
marsh plants, and flat topography of the surrounding marsh could 
potentially allow for long distance seed dispersal. It is unlikely that 
seeds would be dispersed by attachment to animal fur or feathers since 
they have a smooth, glossy seed coat (Service 2005).
    Specific conditions for germination and growth of Cirsium 
hydrophilum var. hydrophilum are not known, but field observations 
suggest they are associated with small gaps or sparsely vegetated 
areas. Dense cover of marsh plants in wet years may restrict the 
establishment of the subspecies (CDWR 1996 and 1999).

Reproduction in Cordylanthus mollis ssp. mollis

    Cordylanthus mollis ssp. mollis, an annual, regenerates from a 
persistent, dormant seed bank. The longevity of seed banks is unknown, 
but some populations fail to emerge for several years and then 
reappear, suggesting

[[Page 18464]]

long-term viability of dormant seeds (Service 2005). The peak seed 
germination period occurs during the most frequent tidal inundations in 
areas of bare soil (CDWR 1994; Ruygt 1994). Seedling growth rapidly 
increases by mid-March when tidal inundations reach an annual low. 
Flowering generally reaches a peak in mid-summer and declines by late 
August. The number of flowers produced per plant varies greatly and 
appears to be dependent on plant height and degree of branching (Ruygt 
1994).
    Cordylanthus mollis ssp. mollis is probably dependent on insects 
for successful pollination and reproduction. Ruygt (1994) observed 
three bee species that were visitors to various C. mollis ssp. mollis 
populations in Napa and Solano Counties. Bumble bees (Bombus 
californicus) were the most frequent visitors seen foraging among 
flowers. The low number of potential pollinators at some locations 
suggests that the subspecies may rely to some degree on self-
pollination to fertilize flowers within larger populations (Ruygt 
1994). During a pollinator exclusion experiment, Ruygt (1994) observed 
that several plants were able to produce seeds through self-
fertilization, but the viability of these seeds were not tested or 
compared to those for non-experimental plants. Grewell et al. (2003) 
observed five bee genera and one bee fly acting as potential 
pollinators at a recently reintroduced population of C. mollis ssp. 
mollis at Rush Ranch and a natural population at Hill Slough Marsh.
    Seed production in Cordylanthus mollis ssp. mollis varies greatly 
among individual plants. Mature plants are multi-branched with each 
branch producing numerous seed capsules. Sampled capsules from three 
populations (Ruygt 1994) contained from 8 to 39 seeds (averaging 23.5 
seeds per capsule). Based on this data, the estimated average seed 
production at Hill Slough Marsh was 495 seeds per plant (Ruygt 1994). 
Stromberg and Villasenor (1986) observed capsules that contained 
between 15 to 40 seeds per capsule at several C. mollis ssp. mollis 
populations. Grewell (2004) observed up to 32,000 seeds per plant under 
ideal growing conditions. However, seed production can be significantly 
influenced by flower, fruit, and seed predation from lepidopteran 
larvae (Ruygt 1994; Grewell et al. 2003).
    Limited information exists on seed dispersal mechanisms for 
Cordylanthus mollis ssp. mollis. Seeds may disperse short distances 
from parent plants by tidal inundations or animals (Grewell et al. 
2003), but successful long distance dispersal by these or other events 
have not been documented. Stromberg and Villasenor (1986) observed that 
most of the mature seed capsules remained closed on parent plants. They 
believed that the majority of the seeds were probably released from 
seed capsules after mature plants fell to the ground and decayed. This 
would likely result in seeds germinating directly beneath parent 
plants. This seed dispersal mechanism may partly explain the reason for 
the high densities of plants often seen in some populations.
    The deep reticulated seed coat (Chuang and Heckard 1972) of 
Cordylanthus mollis ssp. mollis can trap microscopic pockets of air 
that allow seeds to float in saline and fresh water (Ruygt 1994). This 
feature may enable seeds to disperse during tidal events and establish 
local seed banks. Several authors found that tidal events can be 
important agents in seed dispersal for a variety of tidal saltwater and 
freshwater marsh plants (Koutstaal et al. 1987; Huiskes et al. 1995; 
Griffith and Forseth 2002; Wolters and Bakker 2002; Neff and Baldwin 
2005). C. mollis ssp. mollis seeds may persist in dormant seed banks 
for years, but information on the dynamics of these seed banks is 
limited and requires more study (Grewell et al. 2003). Population 
expansion is dependent on viable seeds dispersing to appropriate 
habitats, germinating, and establishing early parasitic connections to 
the roots of suitable tidal marsh host plants.
    The specific PCEs required for Cirsium hydrophilum var. hydrophilum 
and Cordylanthus mollis ssp. mo