 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued September 11, 2014          Decided January 20, 2015

                       No. 13-5136

               CAROL GRUNEWALD, ET AL.,
                     APPELLANTS

                             v.

         JONATHAN B. JARVIS AND SALLY JEWELL,
                      APPELLEES


        Appeal from the United States District Court
                for the District of Columbia
                    (No. 1:12-cv-01738)


    Katherine Anne Meyer argued the cause for appellants.
With her on the briefs was William S. Eubanks II.

    Lane N. McFadden, Attorney, U.S. Department of Justice,
argued the cause for appellees. With him on the brief was
Robert G. Dreher, Acting Assistant Attorney General.

    Before: GARLAND, Chief Judge, PILLARD, Circuit Judge,
and SENTELLE, Senior Circuit Judge.

   Opinion for the Court filed by Senior Circuit Judge
SENTELLE.
                                2

     SENTELLE, Senior Circuit Judge: The National Park Service
of the Department of Interior adopted a plan for the management
of deer in Rock Creek National Park in Washington, D.C. The
plan involved the killing of white-tailed deer. The consideration
and adoption of the plan included the issuance of an
environmental impact statement. Appellants, five individuals
and an organization called “In Defense of Animals,” brought the
present action for declaratory and injunctive relief, alleging that
the Park Service’s plan violated statutes governing the
management of the Park and was not adopted in compliance
with the Administrative Procedure Act. The complaint further
alleged that the environmental impact statement did not meet the
requirements of the National Environmental Policy Act. The
district court granted summary judgment in favor of the
defendants. Plaintiffs brought the present appeal. We affirm.

                         BACKGROUND

     Rock Creek Park in Washington, D.C., was created by Act
of Congress in 1890 as a “public park or pleasure ground for the
benefit and enjoyment of the people of the United States.” Rock
Creek Park Enabling Act (“Enabling Act”), Ch. 1001, § 1, 26
Stat. 492. Originally, the Park was under the joint control of the
Commissioners of the District of Columbia and the Chief
Engineers of the United States Army. Id. § 7. In 1916,
Congress established the National Park Service under the
National Park Service Organic Act, 16 U.S.C. § 1, and the Rock
Creek Park came under the authority of the Park Service. Both
Acts authorize the management of natural phenomena such as
wildlife within the park. The present controversy arises over the
management of the deer population.

    According to the Park Service, few if any white-tailed deer
inhabited Rock Creek Park at the turn of the twentieth century.
See National Park Service, Final White-Tailed Deer
                                3

Management Plan/EIS (“Final EIS”) at ii (2011). Over the
years, however, conditions changed. Areas surrounding Rock
Creek Park became urbanized or suburbanized. Predators, such
as cougars and wolves, no longer populated the mid-Atlantic
region. Deer became increasingly common in Rock Creek Park.
Occasional deer sightings emerged in the 1960s and continued
sporadically throughout the 1970s. By the early 1990s, deer
sightings were so common that the Park Service no longer
recorded individual sightings. In 1989, the Park Service
recorded the first incident of a deer struck and killed by a
vehicle. See id. at 14. From 2003 to 2007, the Park Service
recorded an average of 42 deer-vehicle collisions per year. See
id. at 148.

     Deer are herbivores and generally browse vegetation from
ground level to approximately six feet in height. A large deer
population can result in a visible “browse line,” a line at
approximately six feet above ground level, “below which most
or all vegetation has been uniformly browsed.” Id. at 535. Deer
browsing can adversely impact native vegetation by over-
consuming existing shrubs and herbaceous species. Excessive
browsing of tree seedlings interferes with the forest’s ability to
naturally regenerate itself. See id. at 1.

     By the mid-1990’s, the Park Service began formally
monitoring deer population levels. Based on intensive scientific
evaluation, the Service estimated that, by 2009, Rock Creek
Park would have a deer density of 67 per square mile, or
approximately 315 total deer in the Park. See id. at 56. Given
the increase in deer population and the increase in attendant
problems, the Park Service convened a science team, comprised
of experts from various state and federal agencies, to provide
technical background information and research to support the
preparation of a deer management plan. Science Team Final
Report: Rock Creek Park Deer Management Plan/Environmental
                                 4

Impact Statement (“Science Team Final Report”) (2007). In
September 2006, the Park Service published a notice in the
Federal Register that it intended to prepare a white-tailed deer
management plan and an accompanying environmental impact
statement for Rock Creek Park, and invited comments from the
public. 71 Fed. Reg. 55012, 55012–13 (Sept. 20, 2006). During
the so-called “public scoping,” the Park Service held two public
meetings and received 140 written comments. See National
Park Service, Record of Decision: Rock Creek Park White-
Tailed Deer Management Plan and Final Environmental Impact
Statement (“Record of Decision”) at 11 (2012). In July 2007,
the science team published its summary and recommendations,
suggesting that an initial goal of 15 to 20 deer per square mile in
2009 “would be appropriate for Rock Creek Park.” Science
Team Final Report at 5.

     In 2009, the Park Service published its Draft White-Tailed
Deer Management Plan/Environmental Impact Statement
(“Draft EIS”). The Draft EIS stated a need to address the
“potential of deer becoming the dominant force in the park’s
ecosystem, and adversely impacting native vegetation and other
wildlife,” a “decline in tree seedlings caused by excessive deer
browsing and the ability of the forest to regenerate,” and
“[e]xcessive deer browsing impacts on the existing shrubs and
herbaceous species” as well as on the “character of the [park’s]
cultural landscapes.” Draft EIS at 1–2 (2009). The Plan’s
objectives included protecting “the natural abundance,
distribution, and diversity of native plant species . . . by reducing
excessive deer browsing, trampling, and nonnative seed
dispersal,” and protecting the habitat of birds and “rare plant and
animal species from adverse effects of deer.” Id. at 2. The Draft
EIS identified four alternatives, including a “no-action”
alternative (Alternative A). Under Alternative B, the Park
Service would utilize non-lethal actions for deer control,
including large-scale exclosures and reproductive controls.
                                5

Alternative C would include lethal actions, reducing the size of
the deer herd through sharpshooting or capture and euthanasia.
Alternative D would include both lethal and non-lethal actions,
using lethal actions to quickly reduce the deer herd, with the
possible use of reproductive controls to maintain herd size. Id.
at 41–42. The Park Service identified Alternative D as its
preferred alternative, and as the environmentally preferred
alternative. Id. at 92.

     After releasing the Draft EIS, the National Park Service
announced an extended public comment period and held a
public meeting on its Draft EIS. See Record of Decision at 11.
Over 125 people attended the meeting, and the Park Service
received 414 pieces of correspondence during the comment
period. See id. at 11–12. The Park Service ultimately chose
Alternative D in its Final EIS, finding that a combination of
lethal and non-lethal controls would promote enhanced forest
regeneration, improve the quality of Rock Creek’s scenery and
ecological diversity, and provide flexibility for the potential use
of non-lethal means to control deer herd size. See id. at 8–10.
The Park Service rejected the no-action alternative, Alternative
A, as it would allow deer over-browsing and trampling to
continue to adversely impact native vegetation. Alternative B,
using only non-lethal reproductive controls, would not reduce
the deer population quickly enough, given the long life cycle of
white-tailed deer. Alternative C, using only lethal controls,
would accomplish many of the Park Service’s objectives, but
would not allow future use of non-lethal methods, should the
Park Service later find reproductive controls feasible and
effective in maintaining acceptable deer densities. See id. at
9–10.

    The Park Service published its Final Deer Management Plan
and EIS for public review on January 13, 2012, and issued its
Final Record of Decision on May 1, 2012. Plaintiff–appellants
                                6

filed their complaint in federal district court on October 25,
2012. The parties jointly agreed that the Park Service would
stay implementation of the deer management plan until March
15, 2013, to give the district court time to rule on the merits. On
March 14, 2013, the district court granted summary judgment
for the defendants. Grunewald v. Jarvis, 930 F. Supp. 2d 73
(D.D.C. 2013). Plaintiffs appeal, assigning several grounds of
alleged error. Upon review, we conclude that the National Park
Service acted reasonably and within the scope of its authority,
and therefore affirm.

                           ANALYSIS

     We review the district court’s grant of summary judgment
to the National Park Service de novo, applying the
Administrative Procedure Act standard that “requires us to set
aside agency action that is ‘arbitrary, capricious, an abuse of
discretion, or otherwise not in accordance with law.’” Jicarilla
Apache Nation v. Dep’t of Interior, 613 F.3d 1112, 1118 (D.C.
Cir. 2010) (quoting 5 U.S.C. § 706(2)(A)). Applying that
standard, we consider each of appellants’ allegations of error.

    A. Whether the Deer Management Plan Violates the Rock
Creek Park Enabling Act

      Appellants argue that “the district court erred in deferring
to the agency’s post hoc construction of the Rock Creek Park
enabling statute.” Grunewald Br. 28. This is not precisely the
question before us, as we review the agency’s decision de novo.
The question, then, is not whether the district court erred in its
consideration of the agency’s construction of the statute, but
whether upon review of the administrative record we determine
that the agency’s construction of the Enabling Act is sustainable.
                                 7

    The relevant portion of the Enabling Act reads as follows:

    [T]he public park authorized and established by this act
    shall be under the joint control of the Commissioners of the
    District of Columbia and the Chief of Engineers of the
    United States Army, whose duty it shall be, as soon as
    practicable, to lay out and prepare roadways and bridle
    paths, to be used for driving and for horseback riding,
    respectively, and footways for pedestrians; and whose duty
    it shall also be to make and publish such regulations as they
    deem necessary or proper for the care and management of
    the same. Such regulations shall provide for the
    preservation from injury or spoliation of all timber, animals,
    or curiosities within said park, and their retention in their
    natural condition, as nearly as possible.

Enabling Act, § 7. Although the National Park Service, rather
than the Commissioners and Engineers named in the Enabling
Act, is now responsible for its administration, no one contends
that the Enabling Act no longer applies. As we note further
below, the Organic Act of the National Park Service, 16 U.S.C.
§§ 1, 3, is also relevant, but we nonetheless agree that the
provisions of the Enabling Act are still effective.

     In beginning our review of appellants’ objection to the
agency’s adherence to the Enabling Act, we note that we afford
the Park Service the deference mandated in Chevron, U.S.A.,
Inc. v. NRDC, 467 U.S. 837 (1984). Appellants urge that the
agency is not due such deference, as the Park Service’s position
that the statutes permit the killing of deer is “post hoc,” and first
appeared as the litigation position of the agency in the district
court. Appellants are mistaken. The agency has consistently
treated the Enabling Act as setting forth “the most fundamental
criteria against which the appropriateness of all plan
recommendations” are to be tested. National Park Service, Rock
                                 8

Creek Park Final General Management Plan/EIS at 11–12
(2005). The agency has recognized among those criteria the
mandate to “preserve and perpetuate” the park, its “ecological
. . . resources,” and its “scenic beauty,” in “as natural a condition
as possible.” Id.; Final EIS at 11. The first sentence of the
executive summary of the deer management final environmental
impact statement applies that interpretation of the Enabling Act.
Specifically, the EIS states:

    PURPOSE OF AND NEED FOR ACTION

    The purpose of this action is to develop a white-tailed deer
    (Odocoileus virginarius) management strategy that supports
    long-term protection, preservation, and restoration of native
    vegetation and other natural and cultural resources in Rock
    Creek Park. White-tailed deer herds have increased
    substantially within and around Rock Creek Park. In 2007,
    sampling indicated 82 deer per square mile in the park, and
    deer densities continued at high levels in 2008 (66 deer per
    square mile) and 2009 (67 deer per square mile). Results of
    vegetation monitoring in recent years have documented the
    adverse effects of the large herd size on forest regeneration.

Final EIS at i. The Record of Decision is to the same effect.
See Record of Decision at 1. In short, the agency has
consistently interpreted the Act permitting it to conduct the
proposed killing of deer, and there is nothing post hoc about that
position. Before this court, however, the Park Service raises a
harder line position that the Enabling Act does not apply to the
present deer management plan at all.

     The agency’s hard-line position begins with a meticulous
review of the precise language of the Act. The agency points to
the Act’s last sentence, requiring that “[s]uch regulations shall
provide for the preservation from injury or spoliation of all
                                9

timber, animals, or curiosities within said park, and their
retention in their natural condition, as nearly as possible.”
Enabling Act, § 7. The term “such regulations,” it argues, must
relate back to the last preceding reference to what might be
described as “such regulations.” As the agency argues, that last
reference comes in the next preceding sentence, where the
predecessor agencies of the Park Service are given the duty “to
make and publish such regulations as they deem necessary or
proper for the care and management of the same.” Id. (emphasis
added). The argument of the agency proceeds that this next
raises the question of what referent is intended by the term “the
same.” This time, the Park Service looks back to the earlier
parts of that same sentence which refer to the “duty” of the
agency to “lay out and prepare roadways and bridle paths, to be
used for driving and for horseback riding, respectively, and
footways for pedestrians.” Id. Thus, the Park Service argues,
§ 7 of the Enabling Act refers only to regulations governing
roadways, bridle paths, and footways, and has no applicability
to regulations governing other parts of the park, such as the one
before the court.

     While the agency’s hard-line interpretation has some logic,
we do not find it necessary to uphold that construction of the
statute, as the statute, taken as applying to the regulation of the
whole park, nonetheless is consistent with the Park Service’s
decision in this case. The agency’s fallback position, actually
more consistent with its position in the Record of Decision and
the Environmental Impact Statement, is that even under the
Enabling Act, properly construed, the Park Service has the
authority to implement the plan as presented.

    Taken at its simplest, appellants’ position is that because the
Enabling Act requires that regulations “provide for the
preservation from injury or spoliation . . . animals . . . within
said park . . . as nearly as possible,” a plan which involves
                                 10

killing some animals is not consistent with the authority and
duty granted to the governing agency. However, despite the
simplicity of that interpretation, we agree with the agency that
the meaning of “possible” can no more be taken to the
metaphysical limit of “possibility” than the term “necessary” in
the Necessary and Proper Clause of the Constitution. U.S.
Const. art. I, § 8. Just as there is no question that Congress need
not discover the direst and most absolute necessity in order to
execute its enumerated powers, neither can it be that the Park
Service must refrain from wildlife management unless it can
determine that it is utterly impossible to avoid that form of
management. Under the Chevron analysis, we defer to an
agency’s interpretation, not only where it is the best
interpretation, but where it is merely “reasonable.” Chevron,
467 U.S. at 844. We do not suggest that the agency’s
interpretation of its authority here is not the best, but only assure
that it is at the very least reasonable.

     The National Park Service interpreted the mandate to
preserve animals from harm “as nearly as possible” to permit
killing some animals to prevent serious harms to other natural
resources, even before those harms have fully materialized.
That interpretation was reasonable. We note that the Tenth
Circuit considered a similar issue in interpreting the Secretary
of Interior’s authority under Section 3 of the Organic Act to
“provide in his discretion for the destruction of such animals . . .
as may be detrimental to the use of any of said parks,” 16 U.S.C.
§ 3. In rejecting the argument that something is only
“detrimental to the use” of a park if it causes a present harm, the
court observed:

    The obvious purpose of this language is to require the
    Secretary to determine when it is necessary to destroy
    animals which, for any reason, may be detrimental to the
    use of the park. He need not wait until the damage through
                               11

    overbrowsing has taken its toll on the park plant life and
    deer herd before taking preventive action no less than he
    would be required to delay the destruction of a vicious
    animal until after an attack upon a person.

New Mexico State Game Comm’n v. Udall, 410 F.2d 1197, 1201
(10th Cir. 1969).

      In our focus on the interpretation of the Enabling Act
responsive to the appellants’ assignment of error, we do not lose
sight of the ultimate purpose of our review: We are to uphold the
agency’s action unless it is “‘arbitrary, capricious, an abuse of
discretion, or otherwise not in accordance with law.’” Jicarilla,
613 F.3d at 1118 (quoting 5 U.S.C. § 706(2)(A)). Indeed, in
first setting forth the two-step process of Chevron analysis, the
Supreme Court noted that the review of an agency’s enabling
acts occurred in the context of reviewing regulations that “are
given controlling weight unless they are arbitrary, capricious, or
manifestly contrary to the statute.” Chevron, 467 U.S. at 844.
It was in that context that the Chevron Court observed that “a
court may not substitute its own construction of a statutory
provision for a reasonable interpretation made by the
administrator of an agency.” Id. There is nothing unreasonable
about an agency charged with the preservation of “all timber,
animals, or curiosities within said park,” Enabling Act, § 7
(emphasis added), determining that preventing an imbalance that
allows one species of its protectees to destroy others is within
the power granted by its enabling act.

     The reasonableness of the Park Service’s interpretation of
the Enabling Act, and indeed, the propriety of its decision under
the arbitrary and capricious standard, is buttressed by the fact
that the Park Service is required to comply not only with the
Enabling Act, but also with the National Park Service Organic
Act, 16 U.S.C. § 1, et seq. The Organic Act, which creates the
                               12

Park Service as an agency of the Department of Interior,
provides the Service power to

    promote and regulate the use of the Federal areas known as
    national parks, monuments, and reservations hereinafter
    specified . . . to conserve the scenery and the natural and
    historic objects and the wild life therein and to provide for
    the enjoyment of the same in such manner and by such
    means as will leave them unimpaired for the enjoyment of
    future generations.

16 U.S.C. § 1.

     Further, the Organic Act expressly provides that the
Secretary of the Interior (of whom the Service is the delegee)
“may also provide in his discretion for the destruction of such
animals and of such plant life as may be detrimental to the use
of any said parks, monuments, or reservations.” Id. § 3. Given
the express empowerment under the Organic Act, the agency’s
interpretation is, at the very least, reasonable.

     Appellants discount the effect of the Organic Act by
claiming that the Organic Act is overridden by the Enabling Act.
In support of this proposition, they point to 16 U.S.C. § 1c(b),
which provides, “[e]ach area within the national park system
shall be administered in accordance with the provisions of any
statute made specifically applicable to that area.” Thus, the
normal canon that the later-enacted Organic Act would
supersede the earlier-enacted Enabling Act is inapplicable. That
may be. Nonetheless, our earlier observations, that the agency’s
interpretation of the two Acts as giving it the power it exercises
in the decision under review are consistent and reasonable,
remain undisturbed. In short, we reject appellants’ first
assignment of error.
                                13

    B. Whether the Deer Management Plan is Otherwise
Arbitrary and Capricious

     Aside from their argument that the Deer Management Plan
violates the Park’s Enabling Act, appellants raise other issues
that we analyze under the Administrative Procedure Act.
Appellants contend that “[e]ven accepting the agency’s position
as articulated in its brief to the district court – that ‘NPS must
reduce the deer population if necessary to prevent “injury or
spoliation” of the “timber” and other resources of the Park, “and
their retention in their natural condition as nearly as possible,”’
– the Park Service simply cannot demonstrate that such
circumstances are present here.” Grunewald Br. 31–32 (quoting
NPS Mot. Summ. J. 30, Grunewald v. Jarvis, No. 1:12-cv-1738
(D.D.C. Jan. 25, 2013), ECF No. 18) (emphasis added by
appellants). Appellants claim that the Park Service has not
demonstrated that deer are causing a problem for forest
regeneration, and has not demonstrated that deer, rather than
some other factor (such as invasive, nonnative plant species), are
to blame for any detrimental impacts on native plant species.
Thus, appellants argue, the Park Service has not shown that
killing deer is necessary for the protection of the natural
ecology. See Grunewald Br. 31–39.

     We first observe that appellants have misconstrued the Park
Service’s interpretation of the Enabling Act. Appellants contend
that, under the Park Service’s own interpretation of the Enabling
Act, reduction of the deer population must be necessary to
prevent injury to plant life. However, appellants make this
argument by selectively quoting the Park Service’s district court
summary judgment brief out of context. In the relevant section
of the brief, when the Park Service described the conditions
under which the Enabling Act’s text “arguably compelled” the
killing of deer, it was adverting to a potentially non-
discretionary core of its duty to act. See NPS Mot. Summ. J. 30.
                                14

The Park Service was not thereby delineating its own reasonable
interpretation of the outer limit of its prophylactic management
authority, consistent with the Park’s Enabling Act and agency
Organic Act, to select to kill deer as a prudent strategy to
manage competing natural resources in the Park. Contrary to
appellants’ contentions, and consistent with our analysis of the
governing statutes above, the Enabling Act does not require the
Park Service to wait until killing deer is absolutely necessary to
protect other native species. The agency’s Organic Act gives
the Park Service broad discretion to take preventive measures to
control species overpopulation. See, e.g., New Mexico State
Game Comm’n, 410 F.2d at 1201. In this case, the Park Service
did not need to wait until deer overbrowsing took an even
greater toll on native plant species, that is, until the problem met
the appellants’ definition of “necessary,” before taking action.

     Appellants further claim that the Park Service lacks the
“data it said were needed before it could take any action to kill
deer in this Park.” Grunewald Br. 32 (emphasis in original).
They contend that the Park Service’s science team established
a “threshold for taking action” based on Park staff’s monitoring
of tree seedling counts and deer browsing impacts, and that the
Park Service failed to show that conditions in Rock Creek Park
met this threshold. Id. at 32–37. We disagree. The record
shows that the Park Service met its “threshold for taking action.”
The record documents a dramatic reduction in tree seeding
stocking rates from 1991 to 2007. See Final EIS at 176. Under
high deer densities, such as those present in Rock Creek Park,
normal forest regeneration may be expected to occur when 67%
of observed plots have at least 153 seedlings. See id. at 46.
None of the plots observed in 2007 had 153 or more seedlings
present. Id. at 176.

    Appellants argue that the Park Service’s seedling count
analysis is flawed because it looked at unfenced plots only, and
                               15

thus could not isolate deer as a causal factor. See Grunewald Br.
at 33–35. We are not persuaded by this argument. First, the
failure to undertake paired plot studies does not mean that the
Park Service failed to meet its self-defined “threshold for taking
action.” Monitoring unfenced plots sufficed to meet that
threshold. See Final EIS at 45–46. Second, the Park Service has
conducted a paired plot study to isolate the effects of deer, and
found that detrimental ecological “impacts can be directly
attributed to deer browsing.” Id. at 17. Thus, the Park Service
had the data necessary to meet its “threshold for taking action,”
and did not need to undertake any further studies before
deciding to take lethal action against deer.

     Appellants’ contention that the Park Service had not shown
that deer, rather than some other factor such as invasive plants,
are responsible for harming native plants also fails. The district
court addressed this issue at length, see Grunewald, 930 F.
Supp. 2d at 83–84, 88–90, and we agree with the district court’s
conclusion that the record shows that “the deer are having
negative impacts on Rock Creek Park,” id. at 83. The Park
Service is not required, under the Park’s Enabling Act or
otherwise, to show that deer and only deer are threatening the
native ecology. The Final EIS repeatedly acknowledges the
concurrent threat that invasive plant species pose to the native
ecology. “Anyone reviewing the [Final EIS] does not have to
read far before the subjects of deer management and exotics are
discussed together: there are five mentions of the two subjects
in the first two pages.” Id. at 89. The Park Service has also
shown that deer independently threaten native plants. The Park
Service has compared vegetation cover between fenced and
unfenced plots to help isolate the impacts of deer browsing on
native plants. Final EIS at 17–18. The Park Service has directly
monitored the effects of deer, including observing the effects of
deer browsing. See id. at 14. The Park Service has reasonably,
and on the basis of sufficient evidence, concluded that “deer
                               16

herbivory is having significant negative impacts on forest
vegetation in the park.” National Park Service, Impacts of Deer
Herbivory on Vegetation in Rock Creek Park, 2001-2009 at 10
(2011). Therefore, we hold that the National Park Service’s
Deer Management Plan for Rock Creek Park is not arbitrary,
capricious, or otherwise in contravention of the Administrative
Procedure Act.

      C. Challenges Under the National Environmental Policy
Act

     In addition to their arguments relying on the Enabling Act
and the Administrative Procedure Act, appellants contend that
the Park Service did not comply with the National
Environmental Policy Act (“NEPA”). In reviewing appellants’
arguments on this subject, we recall at the outset that NEPA’s
mandate “is essentially procedural.” Vermont Yankee Nuclear
Power Corp. v. Natural Res. Def. Council, Inc., 435 U.S. 519,
558 (1978). NEPA requires agencies to take a “‘hard look’ at
environmental consequences,” Kleppe v. Sierra Club, 427 U.S.
390, 410 n.21 (1976), and to “provide for broad dissemination
of relevant environmental information,” Robertson v. Methow
Valley Citizens Council, 490 U.S. 332, 350 (1989). It is “well
settled that NEPA itself does not mandate particular results, but
simply prescribes the necessary process.” Robertson, 490 U.S.
at 350. NEPA is “not a suitable vehicle” for airing grievances
about the substantive polices adopted by an agency, as “NEPA
was not intended to resolve fundamental policy disputes.”
Found. on Econ. Trends v. Lyng, 817 F.2d 882, 886 (D.C. Cir.
1987).
                                17

         1. Whether the Park Service Violated NEPA in its
         Failure to Consider Exotic Vegetation Abatement as a
         Fifth Alternative

     Appellants argue that “by failing to consider the reduction
of exotic plant species as an alternative way to protect the native
vegetation in the Park,” Grunewald Br. 39, the National Park
Service violated its NEPA obligation to consider “all
‘reasonable alternatives’ to the proposed action,” Nevada v.
Dep’t of Energy, 457 F.3d 78, 87 (D.C. Cir. 2006) (quoting 40
C.F.R. § 1502.14). Appellants argue that the Park Service has
recognized that the proliferation of exotic plants seriously
threatens native vegetation. They further contend that removing
exotic plants could accomplish the stated objective of the Deer
Management Plan to protect native plants, and that the Park
Service violated NEPA when it refused to consider exotic plant
removal as an alternative to killing deer.

     Again, appellants’ argument is not persuasive. In reviewing
an agency’s selection of alternatives, we owe “considerable
deference to the agency’s expertise and policy-making role.”
City of Alexandria v. Slater, 198 F.3d 862, 867 (D.C. Cir. 1999).
“[W]e review both an agency’s definition of its objectives and
its selection of alternatives under the ‘rule of reason.’”
Theodore Roosevelt Conservation P’ship v. Salazar, 661 F.3d
66, 73 (D.C. Cir. 2011). “[A]s long as the agency ‘look[s] hard
at the factors relevant to the definition of purpose,’ we generally
defer to the agency’s reasonable definition of objectives.” Id.
(quoting Citizens Against Burlington, Inc. v. Busey, 938 F.2d
190, 196 (D.C. Cir. 1991)). “If the agency’s objectives are
reasonable, we will uphold the agency’s selection of alternatives
that are reasonable in light of those objectives.” Id.

    Under this deferential standard, we conclude that the Park
Service did not err when it failed to include removing exotic
                                 18

plants as a stand-alone alternative. In arguing that the Park
Service could have achieved its stated objectives without killing
deer, appellants quote selectively from the record. They
emphasize the Management Plan’s objectives to “[p]rotect the
natural abundance, distribution, and diversity of native plant
species,” and “[m]aintain, restore, and promote a mix of native
plant species and reduce the spread of nonnative plant species.”
Final EIS at i (quoted in Grunewald Br. 40). However,
appellants omit other, more specific objectives that the Park
Service cannot accomplish through plant management alone.
These objectives include “[p]rotect[ing] habitat of rare plant and
animal species from adverse effects of deer, such as excessive
deer browsing, trampling, and nonnative seed dispersal”; and
“[p]rotect[ing] the integrity, variety, and character of the cultural
landscapes by reducing excessive deer browsing, trampling, and
nonnative seed dispersal.” Final EIS at ii.

     The Park Service reasonably determined that the
overpopulation of white-tailed deer in Rock Creek Park
detrimentally affects the Park’s ecology. Given this concern, it
was not unreasonable for the Park Service to define its
objectives in terms of abating the effects of deer browsing and
trampling. A stand-alone exotic plants management plan would
not address the deer problem. The agency did not adopt “an
‘unreasonably narrow’ definition of objectives that compels the
selection of a particular alternative.” Theodore Roosevelt, 661
F.3d at 73. Instead, it reasonably defined its objectives and
alternatives in light of its legitimate concern with deer
populations. Accordingly, the Park Service did not violate
NEPA when it did not consider a “plants-only” option as an
alternative.
                               19

         2. Whether NEPA Requires the National Park Service
         to Analyze the 2004 Draft Exotic Plant Management
         Plan as a “Connected” or “Similar” Action

     Appellants argue the Park Service violated NEPA when the
Park Service did not analyze its 2004 Draft Exotic Plant
Management Plan in the same NEPA document as its Deer
Management Plan. Appellants contend that an agency should
consider “connected” or “similar” actions within a single NEPA
document. Connected actions are “closely related and therefore
should be discussed in the same impact statement.” 40 C.F.R.
§ 1508.25(a)(1). Similar actions are those “which when viewed
with other reasonably foreseeable or proposed agency actions,
have similarities that provide a basis for evaluating their
environmental consequences together.” Id. at § 1508.25(a)(3).
Therefore, appellants contend, the National Park Service’s 2004
Draft Exotic Plant Management Plan, which aims to combat the
proliferation of invasive plants in Rock Creek Park, is a
“connected” or “similar” action and the Park Service should
have considered it alongside the Deer Management Plan within
a single programmatic EIS. We disagree. The Park Service did
not violate the requirements of NEPA by analyzing the 2004
Draft Exotic Plant Management Plan and the Deer Management
Plan in different documents. “Even when [an EIS addresses]
one of a series of closely related proposals, the decision whether
to prepare a programmatic impact statement is committed to the
agency’s discretion.” Izaak Walton League of Am. v. Marsh,
655 F.2d 346, 374 n.73 (D.C. Cir. 1981). “Only if the decision
is arbitrary and capricious will we overturn it.” Nevada, 457
F.3d at 92 (citations omitted). In determining whether a
programmatic EIS is necessary, we consider “the extent of the
interrelationship among proposed actions and practical
considerations of feasibility.” Kleppe, 427 U.S. at 412.
                                20

     We reject appellants’ contention that the Park Service was
required to consider the Draft Exotic Plant and Deer
Management Plans together in a single EIS as similar actions.
The regulation cited by appellants does not support appellants’
contentions. Defining “similar actions,” the regulation provides
that an agency “may wish to analyze [similar] actions in the
same impact statement,” and “should do so when [it is] the best
way to assess adequately the combined impacts of similar
actions or reasonable alternatives.” 40 C.F.R. § 1508.25(a)(3)
(emphasis added).

      The Park Service did not act arbitrarily, but rather exercised
its lawful discretion, when it declined to analyze the Exotic
Plant and Deer Management Plans together. While the Park
Service acknowledges that the subjects of deer management and
invasive species management are “in some ways related,” the
Park Service maintains that they are distinct actions “addressed
in two different planning efforts.” Final EIS at 380. Appellants
point out that the Rock Creek Park General Management Plan
lists future “invasive species control” and “deer management”
implementation plans as “[c]onnected, [c]umulative, and
[s]imilar [a]ctions.” See Grunewald Br. 42–43. However, the
fact that each plan may be related to the Park’s General
Management Plan (which is the “basic document for managing
Rock Creek Park,” Rock Creek Park Final General Management
Plan at 1) does not mean that the plans are so closely related to
each other that NEPA requires concurrent analysis of deer
management and exotic plant control. As the Supreme Court
has held, “[a]n agency enjoys broad discretion in determining
how best to handle related, yet discrete, issues in terms of
procedures and priorities.” Mobil Oil Exploration & Producing
Se. Inc. v. United Distribution Cos., 498 U.S. 211, 230 (1991)
(citations omitted). The Park Service has not abused that broad
discretion here.
                               21

     Similarly, appellants’ contention that the Park Service
arbitrarily failed to consider the Deer Management and Draft
Exotic Plant Plans together as “connected” actions is unavailing.
Under the regulation, actions are “connected” if they
“[a]utomatically trigger other actions which may require
environmental impact statements”; “[c]annot or will not proceed
unless other actions are taken previously or simultaneously”; or
“[a]re interdependent parts of a larger action and depend on the
larger action for their justification.” 40 C.F.R. § 1508.25(a)(1).

     Again, the Park Service acted within its discretion when it
declined to analyze the Exotic Plant and Deer Management
Plans together as “connected” actions. Nothing in the record
indicates that any of the regulatory definitions of “connected”
apply. Neither Plan automatically triggers other reportable
actions. Actions pursuant to the Deer Management Plan have
already proceeded, and have not depended on the concurrent or
previous undertaking of the Draft Exotic Plant Plan or some
other action. The Plans are not interdependent parts of a larger
action. The fact that the Plans have similar goals, protecting the
native ecology, does not make the plans sufficiently intertwined
to require concurrent NEPA analysis. “[A]n agency need not
solve every problem before it in the same proceeding.” Mobil
Oil, 498 U.S. at 231. A court “cannot force an agency to
aggregate diverse actions to the point where problems must be
tackled from every angle at once. To do so risks further
paralysis of agency decisionmaking.” Nw. Res. Info. Ctr., Inc.
v. Nat’l Marine Fisheries Serv., 56 F.3d 1060, 1069 (9th Cir.
1995) (citation omitted). We hold that the Park Service did not
err in concluding that the Deer Management and Exotic Plant
Plans are not “similar” or “connected” for the purposes of
NEPA.
                                22

         3. Whether the National Park Service Violated NEPA
         by Failing to Consider the Deer Management Plan’s
         Effects on the “Human Environment”

     Appellants argue that the National Park Service “violated
NEPA by failing to consider the adverse impact its decision to
kill wildlife will have on the public’s ability to enjoy this
extremely special national park which for over 120 years has
been . . . completely free of any violence against wildlife.”
Grunewald Br. 52. Appellants reason that NEPA requires an
agency to consider “the environmental impact of the proposed
action,” 42 U.S.C. § 4332(C), including the “aesthetic” aspects
of a decision, 40 C.F.R. § 1508.8, and how the action will affect
“the relationship of people with [the natural and physical]
environment,” id. § 1508.14. Appellants stress the views of park
goers, expressed in several public comments, that allowing the
killing of deer will “significantly mar their ability to enjoy using
this Park” and “fundamentally transform the overall character of
the Park from a tranquil place . . . to a place where wildlife is
shot, maimed, and killed” regularly. Grunewald Br. 53. They
maintain that the district court wrongly dismissed these concerns
as mere “psychological harms,” and that the Park Service did
not adequately consider and address them. We disagree.

     The National Park Service complied with NEPA by
adequately considering the Deer Management Plan’s effects on
the human environment. The Final EIS discusses at length the
potential impacts of each alternative on visitor use, experience,
and safety. Final EIS at 240–55. The EIS discusses the costs
and benefits of archery and sharpshooting; the possibility of
adverse impacts on those who might see or hear the killing;
ways to prevent visitor encounters with dead or dying deer; and
mitigating the impact of gunshots on the “soundscape” of the
park. Id. The Plan mitigates its effects on visitor experience by
limiting culling activities to night or times when the park is
                               23

closed; concentrating activities during winter months, when
there are fewer visitors; and separating visitors from culling
activities or uncollected deer carcasses. See Record of Decision
at 5. In short, the Park Service adequately considered the
impacts that killing deer could have on the human environment.
It squarely addressed the potential effects on visitors of seeing
or hearing the killing of deer, and other tangible and physical
impacts of the Plan.

     The National Park Service was not required to consider the
psychological harm that some visitors may suffer from simply
knowing that the intentional killing of deer happens at Rock
Creek Park. The appellants fail in their attempt to recast their
psychic injuries as concerns relating to visitor experience and
the human environment. They claim that the killing of deer
fundamentally changes the character of the Park and destroys its
value to some visitors. However, once we set aside what the
Park Service has addressed (witnessing killings, encountering
carcasses, hearing gunshots, etc.), appellants’ claim supports at
most a psychological harm—appellants’ knowledge that deer are
killed, even if they perceive no such killings. NEPA requires
agencies to consider “the effect of their proposed actions on the
physical environment.” Metropolitan Edison Co. v. People
Against Nuclear Energy, 460 U.S. 766, 772 (1983) (emphasis
added). NEPA does not require an agency to consider the
potential that its action may remotely cause “psychological
health damage” for some members of the public. Id. at 775–76.
The Park Service adequately and comprehensively considered
the impacts of its proposed alternatives on the “human
environment.” It was not obligated to address the potential for
some members of the public to be psychologically harmed by
simply knowing that deer are killed in Rock Creek Park; this
kind of remote impact is outside the scope of NEPA.
                               24

                         CONCLUSION

     While there might not have been any white-tailed deer
present in Rock Creek Park at its founding in 1890, deer
populations have risen dramatically since the first deer sightings
in the 1960s. With no natural predators, deer populations grew
unabated. While the native deer are a valued park resource, the
National Park Service became concerned with the deer’s
ecological impacts. The National Park Service, exercising its
expertise, studied the deer and their effects on Rock Creek Park.
The Park Service concluded that the deer pose a threat to the
Park’s native ecology, and proposed taking action to reduce the
deer population to sustainable levels. The Park Service
eventually decided to take lethal action against the Park’s deer,
quickly reducing the herd to an ecologically sustainable level.
The Park Service held open the potential future use of
contraceptives to maintain population levels. In reaching this
decision, the Park Service fully complied with the Rock Creek
Park Enabling Act, the Administrative Procedure Act, and the
National Environmental Policy Act. Therefore we affirm the
judgment of the district court.

                                                     So ordered.
