[Federal Register: December 6, 2006 (Volume 71, Number 234)]
[Proposed Rules]               
[Page 70715-70717]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]



Fish and Wildlife Service

50 CFR Part 17

Endangered and Threatened Wildlife and Plants: 90-Day Finding on 
a Petition To List the Upper Tidal Potomac River Population of the 
Northern Water Snake (Nerodia sipedon) as an Endangered Distinct 
Population Segment

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 90-day petition finding.


SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
90-day finding on a petition to list the distinct vertebrate population 
segment (DPS) of the northern water snake (Nerodia sipedon) in the 
upper tidal Potomac River as endangered under the Endangered Species 
Act of 1973, as amended (Act). We find the petition does not provide 
substantial scientific or commercial information indicating that the 
petitioned action is warranted. Therefore, we will not initiate a 
further status review in response to this petition. We ask the public 
to submit to us any new information that becomes available concerning 
the status of this population of the northern water snake or threats to 

DATES: The finding announced in this document was made on December 6, 

ADDRESSES: The complete file for this finding is available for public 
inspection, by appointment, during normal business hours, at the 
Chesapeake Bay Field Office, U.S. Fish and Wildlife Service, 177 
Admiral Cochrane Drive, Annapolis, Maryland 21401. Submit new 
information, materials, comments, or questions to us at the above 

FOR FURTHER INFORMATION CONTACT: John Wolflin, Field Supervisor, 
Chesapeake Bay Field Office (see ADDRESSES) (telephone 410-573-4574; 
facsimile 410-269-0832).


[[Page 70716]]


    Section 4(b)(3)(A) of the Act (16 U.S.C. 1531 et seq.) requires 
that we make a finding on whether a petition to list, delist, or 
reclassify a species presents substantial scientific or commercial 
information indicating that the petitioned action may be warranted. We 
are to base this finding on information provided in the petition and 
information available in our files. To the maximum extent practicable, 
we are to make this finding within 90 days of our receipt of the 
petition, and publish our notice of the finding promptly in the Federal 
    Our standard for substantial information within the Code of Federal 
Regulations (CFR) with regard to a 90-day petition finding is ``that 
amount of information that would lead a reasonable person to believe 
that the measure proposed in the petition may be warranted'' (50 CFR 
424.14(b)). If we find that substantial scientific or commercial 
information is presented, we are required to promptly commence a status 
review of the species.
    In making this finding, we relied on information provided by the 
petitioner and evaluated this information in accordance with 50 CFR 
424.14(b). Our process of making a 90-day finding under section 
4(b)(3)(A) of the Act and Sec.  424.14(b) of our regulations is limited 
to a determination of whether the information in the petition meets the 
``substantial information'' threshold.
    On November 7, 2000, we received a formal petition dated November 
1, 2000, from Dr. Richard M. Mitchell requesting that we emergency list 
the northern water snake population found in the upper tidal Potomac 
River as a distinct population segment (DPS) under the Act. The 
petition included a report from a study performed by Dr. James M. Beers 
and Dr. Mitchell from July to September, 2000, entitled ``A 
Herpetofaunal Survey of the Upper Tidal Potomac River and its 
Associated Estuaries.''
    Action on the petition was precluded by court orders and settlement 
agreements for other listing actions that required nearly all of our 
listing funds for fiscal year 2001. However, the Service did evaluate 
the need for emergency listing based on the information provided in the 
initial petition and its attached report and determined that the 
threats described did not appear to constitute immediate threats of a 
magnitude that would justify emergency listing. A letter was sent to 
the petitioner on January 23, 2001, explaining this determination.

Species Information

    The northern water snake was first described by Linnaeus in 1758. 
The species is widely distributed in eastern North America, from 
southern Canada south through the Carolina and Georgia Piedmont, to the 
Gulf of Mexico, and west to eastern Colorado (Conant 1975, p. 145). 
This species occurs in most freshwater habitats within its range, 
inhabiting natural water bodies, wetlands, and even manmade 
impoundments (Dorcas and Gibbons 2004, p. 183). Northern water snakes 
tend to exhibit high site fidelity, although snakes in linear habitats 
such as rivers tend to wander more than snakes in discrete habitats 
such as ponds (Fraker 1990, pp. 666-669). The northern water snake is 
found in a diversity of habitats, and likewise consumes a diversity of 
prey. In fact, Gibbons and Dorcas (2004, p. 186) state, ``the 
documented diversity of prey species consumed by N. sipedon is greater 
than for any other water snake * * * [this] clearly indicates that N. 
sipedon is primarily an aquatic-feeding generalist that in most 
instances probably eats whatever is readily available.''
    The northern water snake is a moderately sized, nonvenomous water 
snake, and is highly variable in both dorsal and ventral color patterns 
(Dorcas and Gibbons 2004, p. 178). Selective pressure, namely 
predation, determines which banding patterns are exhibited in specific 
populations (Camin and Ehrlich 1958 in Beatson 1975, p. 241). This 
natural selection results in individuals with cryptic coloration that 
is highly specialized for their habitat. Coloration, when broken down 
into the most basic classes, ranges from the regularly banded morph, to 
a reduced pattern morph, to a uniformly unbanded morph (King and Lawson 
1995, p. 885). Most northern water snakes meet the standard description 
(i.e., the regularly banded morph); however, ``the range of variability 
cannot be overstated'' (Dorcas and Gibbons 2004, p. 179).
    Focusing on the geographic area of the petitioned action, the 
northern water snake is found throughout Maryland and Virginia, and its 
distribution in the Washington DC Metropolitan area of the Potomac 
River appears concentrated from just north of Great Falls National Park 
southward to just north of Indianhead, Maryland (Mitchell 1994, p. 

Distinct Vertebrate Population Segment

    We consider a species for listing under the Act if available 
information indicates such an action might be warranted. ``Species'' is 
defined by the Act as including any subspecies of fish or wildlife or 
plants, and any distinct population segment of any species of 
vertebrate fish or wildlife that interbreeds when mature (16 U.S.C. 
1532(16)). We, along with the National Marine Fisheries Service (now 
the National Oceanic and Atmospheric Administration--Fisheries), 
developed the Policy Regarding the Recognition of Distinct Vertebrate 
Population Segments (61 FR 4722; February 7, 1996), to help us in 
determining what constitutes a DPS. The policy identifies three 
elements that are to be considered regarding the status of a possible 
DPS. These elements include: (1) The discreteness of the population in 
relation to the remainder of the species to which it belongs; (2) the 
significance of the population to the species to which it belongs; and 
(3) the population segment's conservation status in relation to the 
Act's standards for listing. The following is our evaluation of these 
elements in relation to the petitioned entity, the upper tidal Potomac 
River population of the northern water snake.
    Discreteness: The DPS policy states that a population segment of a 
vertebrate species may be considered discrete if it satisfies either 
one of the following two conditions: (1) It must be markedly separated 
from other populations of the same taxon as a consequence of physical, 
physiological, ecological, or behavioral factors; or (2) it must be 
delimited by international governmental boundaries within which 
difference in control of exploitation, management of habitat, 
conservation status, or regulatory mechanisms exist that are 
significant in light of section 4(a)(1)(D) of the Act.
    The petitioner claims that the color pattern of the upper tidal 
Potomac River population of the northern water snake is different from 
dorsal patterns of other water snakes in Virginia. However, as 
referenced earlier, the northern water snake is highly variable in both 
dorsal and ventral color patterns (Dorcas and Gibbons 2004, p. 178). 
Therefore, color pattern alone does not provide sufficient information 
to support marked separation from other populations of the same taxon 
as a consequence of physical factors.
    In summary, the petitioner does not present any evidence to 
indicate that the species is markedly separated from other populations 
of the same taxon by physical, physiological, ecological, or behavioral 
factors, nor is it delimited by an international governmental boundary. 
The northern water snake within the upper tidal Potomac River

[[Page 70717]]

therefore does not meet the ``discreteness'' criterion.
    Significance: Pursuant to our DPS policy, in addition to our 
consideration that a population segment is discrete, we further 
consider its biological and ecological significance to the taxon to 
which it belongs, within the context that the DPS policy be used 
``sparingly'' while encouraging the conservation of genetic diversity 
(61 FR 4722; February 7, 1996). This consideration may include, but is 
not limited to: (1) Evidence of the persistence of the discrete 
population segment in an ecological setting that is unique for the 
taxon; (2) evidence that loss of the population segment would result in 
a significant gap in the range of the taxon; (3) evidence that the 
population segment represents the only surviving natural occurrence of 
a taxon that may be more abundant elsewhere as an introduced population 
outside its historical range; and (4) evidence that the discrete 
population segment differs markedly from other populations of the 
species in its genetic characteristics.
    The petition does not address these factors. Therefore, based on 
the lack of information in the petition and the information readily 
available in our files, the upper tidal Potomac River population of the 
northern water snake is not significant in relation to the remainder of 
the taxon.


    We reviewed the information presented in the petition, and 
evaluated that information in relation to information readily available 
in our files. On the basis of our review, we find that the petition 
does not provide substantial scientific or commercial information to 
indicate that the upper tidal Potomac River population of the northern 
water snake constitutes a valid DPS. This finding is based on the lack 
of substantial evidence indicating this population meets the 
discreteness element of the DPS policy and the lack of substantial 
scientific information that the upper tidal Potomac River population is 
significant in relation to the remainder of the taxon. Therefore, we 
conclude that the upper tidal Potomac River population of the northern 
water snake is not a listable entity pursuant to section 3(15) of the 
Act. We will not be commencing a status review in response to this 
petition. However, we encourage interested parties to continue to 
gather data that will assist with the conservation of the species. 
Information regarding this species may be submitted at any time to the 
Field Supervisor, Chesapeake Bay Field Office (see ADDRESSES section).

References Cited

    A complete list of all references cited herein is available, upon 
request, from the Chesapeake Bay Field Office (see ADDRESSES section).


    The primary author of this notice is Charisa Morris, U.S. Fish and 
Wildlife Service, Chesapeake Bay Field Office (see ADDRESSES section).


    The authority for this action is section 4 of the Endangered 
Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).

    Dated: November 28, 2006.
Kenneth Stansell,
Acting Director, U.S. Fish and Wildlife Service.
 [FR Doc. E6-20542 Filed 12-5-06; 8:45 am]