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Restoring
the
Urban Ecosystem
of Central Park’s
North End
Janet Fang
Abstract
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The Restoration Site |
History
– According to the Central Park Conservancy, before it became “an urban
wonder
of the world,” Central Park was 843 acres of
rocky, swampy,
muddy terrain. This undeveloped land was purchased for approximately $5
million
in the mid-19th Century by New York City’s commissioners,
who saw
the need for public green space. In 1858, Frederick Law Olmsted and
Calvert
Vaux created the “Greensward Plan” to make this space into the first
major park
intended entirely for public use, trusting in nature’s ability to act
as a
haven against the drudgery of city life; this plan was part of a
competition
sponsored by city commissioners to design a new park. To Olmsted,
Central Park
“is of great importance as the first real Park made in this century – a
democratic development of the highest significance.” Olmsted and
Vaux will come to be known as the creation
ecologists behind
Central Park.
For decades,
Central Park was used
for the purposes it was created, but its heavy use also meant that it
has
succumbed to much degradation, including pollution, soil compaction,
and erosion.
By the end of the 19th Century, automobiles became a new
stress upon
the park, and by the early 20th Century, the park began to
degrade
out of negligence.
The first
restoration project for
Central Park took place in 1934. By then, Central Park was in near
ruins and
its “lawns, unseeded, were expanses of bare earth, decorated with
scraggly
patches of grass and weeds that became dust holes in dry weather and
mud holes
in wet.” But the positive results of this restoration project were was
short-lived and the park continued to deteriorate well past the mid-20th
Century. In 1980, the Central Park Conservancy was formed and a new
master
restoration plan was begun: “Rebuilding Central Park for the 1980s and Beyond.” Together with the city, the Conservancy
signed a
contract that would ensure the continuing maintenance of Central Park.
Background
to the Restoration Site, At Present – The focus of this project
is on
the continuous water/stream system of the Pool, the Loch, and the
Ravine in the
North End of Central Park in Manhattan, New York (figure 2). The Pool
lies just
south of the park entrance at 103rd Street and Central Park
West. From
there, the Ravine (which includes the Loch) flows northeastward and
terminates
down a metal-grated hole in the ground between Huddlestone
Arch and Lasker Pool/Rink, just south of
106th
Street.
Presently, the Pool (figure 1) is a two-acre body of water fed into by a 48-inch pipe hidden behind a boulder in its southwest corner. Water is brought from the Reservoir, which lies between 97th and 86th Streets and is the main source of water that keeps many of the water bodies within the park running. The grassy bank of the Pool is sparsely surrounded by willows, red maples, thickets, and shrubs, and aquatic plants line the water’s edge. As the Ravine flows out of the Pool, the scenery changes to a canopy of oaks, elms, and maple, until the environment becomes a deciduous forest of oak, hickory, maple, and ash (figure 4). The floor is covered with deadwood, herbaceous plants, and sometimes a thick layer of leaf litter. The Loch, which was originally designed to be a small lake, has since reverted to its pre-park stream form where the streamside thickets grow on islands of accumulated silt. The Ravine/Loch is the only stream valley in the park and is part of a 90-acre woodland named North Woods. The stream ends as it drains into the conduit underground, just downstream from Huddlestone Arch (figure 5).
Many vertebrate species inhabit this riparian woodland. This includes over 200 species of birds seen regularly throughout the park, including year-round birds and annual migrants, with families that span across the phylogenetic spectrum from Gaviidae (loons) to Fringillidae (finches), according to The Birds of Central Park. Central Park has become grounds for their breeding, nesting, and wintering, providing them with food and shelter resources in this isolated green space within New York City.
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Current Problems |
Because of its location, Central Park’s
North End faces many
problems, which includes water pollution, heavy foot-traffic, off-trail
trampling,
littering, and vandalism and other illegal activities. This restoration
project
will focus on three specific threats that are particularly troublesome
to the
wildlife species that depend on this space: noise pollution, light
pollution,
and the urban heat island effect.
Noise Pollution – While parts of the stream were deliberately dammed to create the sounds of cascades, any potentially pastoral intonations are nearly drowned out by the cacophony of cars (traffic, sirens, car alarms), helicopters and airplanes overhead, and people in general (amplified music, crowds). All this contributes to the ambient city noise.
The effects of noise pollution are numerous. It most poignantly threatens the biodiversity of song birds that inhabit the streamside thickets. Human-altered environments are changing the communication signals of wild bird species (Brumm & Todt, 2002), (Patricelli & Blickley, 2006), (Warren, 2006). Urban song birds sing at a higher frequency than their rural counterparts so that their songs stand out better against the city noise, which tends to be at lower frequency. New kinds of machinery that were not present in the evolution of song birds have created a new selection pressure on wildlife species that use acoustic signals to achieve reproductive success (Slabbekoorn & Peet, 2003). Two dominant environmental factors affecting signal efficiency for birdsong are sound transmission properties and the level of interference by ambient noise. Successful acoustic communication requires that sounds propagate through the environment between the sender and receiver; vocalizations that transmit effectively in the habitat in which they are used are favored by natural selection, through a process known as acoustic adaptation. This differential selection is expected to create two groups of species: those that can adapt their signals to the competing noise, and those that cannot. For those species in the latter group, anthropogenic noise affects breeding opportunities, forcing them to suffer from auditory masking, and ultimately contribute to a decline in species density and diversity (Wood & Yezerinac, 2006). Globally, this phenomenon of responding to anthropogenic changes in the acoustic environment by altering their songs, has been documented in great tits of Leiden, Netherlands (Slabbekoorn & Peet, 2003), which was also the inaugural study of urban birdsong, house finches in southern California (Fernández-Juricic, 2005), nightingales in Germany (Brumm, 2004), and song sparrows in Portland, Oregon (Wood & Yezerinac, 2006). Within Central Park’s North End, the affected species include song sparrows (Melospiza melodia) and nonnative birds, such as blackbirds (Family Icteridae), and European passerines like the house sparrow (Passer domesticus).
The mechanisms of acoustic adaptation have not been fully understood. For those song species that have managed to sustain themselves in the city, it’s hypothesized that either (1) random mutations in behavioral plasticity have allowed them to pass on their altered (and thus successful) songs to the male sons that they sire, or (2) some birds who possess a wide range of frequencies can tailor their songs to their environments (Slabbekoorn & Peet, 2003).
Male song birds have good reason to maintain clear song transmission because their reproductive success depends on it. Songs play a role in male-male conflicts, functioning to maintain territories and repel intruding males, and female mate choice in song birds is also heavily influenced by male song. The proximate pressures are intimately coupled with sexual selection. However, sexual selection is often contrary to natural selection (Darwin, 1874). Although higher-frequency songs may improve communication efficiency for song birds in noisy environments, this may come at a cost. In noisier locations, song birds may sing more loudly, which has been shown to increase rates of oxygen consumption and energy expenditure. The possible effects of vocal modifications in response to anthropogenic noise may actually decrease individual health (Wood and Yezerinac, 2006).
This then begins the divergence of song
phenotypes between
urban and rural metapopulations. Urban versus rural is certainly the
central
subdivision of species at the heart of this discussion. As previously
inferred,
should migration or dispersal occur between the city and countryside,
there may
not be any species recognition. Does Central Park (or Manhattan in
general) have
its own subspecies of song birds? The answer is most likely no, because
there
are no actual biological restrictions at play, just behavioral,
although
sometimes behavioral differences are enough to constitute a species or
subspecies boundary. There are further subdivisions of song birds in
New York.
Since the city is not homogenously good, patchiness results, which in
turn
results in metapopulations within the city. So song birds have settled
into the
patches, and most likely, each patch is characterized by a different
noise
disturbance. It’s entirely possible that even the general phrase
“higher
frequency song” that has been used here can be further complicated into
different degrees of high frequency because the sounds of urban noise
is so
varied. A species is the sum of all its metapopulations, and there
needs to be
multiple populations in attempts to secure the persistence of the
species. So urban song birds on the whole will
persist (especially because
their year-round range spans across the
In the long-term, through magnifications in a biological chain of events, these specialized urban birds are only mating with other local city birds, ultimately reducing their genetic diversity and opening up opportunities for the deleterious effects of small or isolated populations. Evolutionary restoration ecology and population genetics must play a large role in the management of these song species.
Although the mechanisms of acoustic
adaptation are
undetermined, it’s not likely that these song species possess enormous
behavioral
plasticity and are then capable of changing the frequency at which they
sing at
will, after they’ve made an assessment of the frequency of the ambient
noise.
It’s far more likely that this sexual selection took generations,
beginning
with an individual that, by chance, sang at a higher frequency and was
better
heard by females and whose territory was better announced to competitor
males;
because selection is simply differential reproduction, this bird in
this
specific case has a better chance of mating success and was thus better
equipped to pass on his genes, which, presumably, includes the tendency
to sing
a higher frequency song. This presupposes that singing at higher
frequencies is
a heritable trait, although, it is also likely that what is heritable
is not so
much the particular song or singing ability, but the behavior of
teaching his
male offspring this particularly high-frequency song.
According to Foundations of Restoration
Ecology (2006),
genetic variants that evolved within historically different
evolutionary
contexts may thus be pitted against novel and mismatched current
conditions,
and that the degree of this mismatch should then determine the pattern
and
strength of selection acting on trait variation in such populations.
Contemporary
evolution should occur whenever there is sufficient heritable variation
for a
trait under directional selection with selection favoring a shift in
the mean
trait value toward the optimum (highest net fitness value). This
selection
pressure for songs pitched at higher frequencies is a stunning example
of
contemporary evolution in the face of anthropogenic disturbances: the
proliferation of a trait (singing at higher frequencies) in a
population
(Central Park song birds) through a stimulus (urban noise pollution).
Genetic diversity serves as the basis for
adaptive evolution
in all living organisms and that heritable
differences
among individuals influence how they interact with the physical
environment and
how they function within ecosystems. We already know that the extant
Central
Park song birds have taken advantage of their existing genetic
diversity. That
explains how they have been able to amplify their songs above the
city’s white
noise: there was a genetic variant for songs occurring at higher
frequencies.
However, if genetic diversity is the primary basis for adaptation to
environmental uncertainty, the future of these Central Park song birds
is in
danger because they have become so specific to their isolated location.
Generally,
it is not entirely detrimental to become highly specialized relative to
the
ecosystem, but in the case of this urban ecosystem, the problems are
numerous.
Most poignantly, urban song birds are slowly losing, through strong
selection
pressures acting in the opposite direction, their ability to sing at
the
“normal” pitch. Rural females will not recognize the breeding songs of
urban
males, so these males are restricted to only urban females,
correspondingly.
These Central Park song species are not only living in isolated
populations,
but even if they were to come into contact with other populations,
there is a
good chance that there will be no species recognition.
Additionally, populations with individuals containing different genes for adaptation to new conditions are more likely to persist, but populations with a narrower range of genotypes (more phenotypically uniform) may fail to survive and reproduce as conditions become less locally favorable. So this introduces a timeliness element to this restoration project; noise pollution must be reduced before song species establish a unilateral runaway acoustic adaptation and have lost all genetic capabilities to sing at their normal frequencies.
And finally, noise pollution also makes Central Park less of the pastoral retreat for urbanites than it was originally designed to be.
Light Pollution – The unnatural glow of cities (which includes over-illumination, glare, clutter, and sky glow), resulting from automobiles, street lamps, and brightly-lit sky scrappers disrupt the natural light-dark cycles. This “ecological light pollution” (Longcore and Rich, 2004) affects the behaviors of wildlife by increasing the length of the photoperiod for plants and by creating extended pseudo-daylight hours for diurnal birds.
Animals can experience disorientation from additional illumination and are attracted to or
repulsed by glare, which affects foraging, reproduction, communication, and other critical behaviors (Longcore and Rich, 2004). Artificial light disrupts interspecific interactions evolved in natural patterns of light and dark. Birds rely on both internal and external mechanisms for reproduction and migration. As a result of light pollution, male birds may continue to expend energy singing their higher frequency songs past daylight hours. Migrating birds are extremely disoriented by city night-lights. Night-migrating birds are especially attracted to lighted areas; that, combined with windows, glass, and other reflective surfaces of brightly-lit tall buildings, are resulting in fatal collisions. These fatalities number in the hundred millions per year, in American cities alone.
Additionally, according to the Fatal Light Awareness Program (FLAP), once inside a beam of light, such as those projected by the light posts that line the major streets of Central Park, birds oftentimes do not want to leave the lit area to enter into the dark sky. So they will continuously flap around within the beam of light. Not only does this make them more visible to nocturnal predators, such as owls, this incessant flapping eventually ends when they drop to the ground out of exhaustion, making them further vulnerable to predators.
The unnatural light-dark cycles have affects on the physiological processes of plants as well, especially seed-germinating species and flowering plants. Seasonal events are important in the life cycles of most photosynthetic plants. The environmental stimulus that most plants use to detect the time of year is the photoperiod, which is the relative length of night and day. Night length, and not day length, actually controls the physiological responses to photoperiod. If the nighttime part of the photoperiod is interrupted by light, or is cut short of the critical night length, many species will not flower (Campbell, 1999). Without flowering, there is no sexual reproduction, and these plants face a decline on account of their ecophysiological constraints.
Also facing decreased reproduction rates are plants that depend on nocturnal insect-pollinators. Nighttime light interferes with the ability of moths and other nocturnal insects to navigate (Longcore and Rich, 2004).
Urban Heat Island – This is defined as a metropolitan area that is significantly warmer than its rural surroundings. Among its many causes are buildings that block the view to the colder night sky, the lack of evapotranspiration, the common use of surface materials with higher heat capacity and thermal conductivity, and CO2 emissions and land-use developments that contribute to fluxes in the natural carbon cycle. (The language of the urban heat island is similar to climate change and global warming.)
City
birds are strongly affected by unnatural thermodynamics (Oke, 1982).
Similar to the effects of
light pollution, the artificial warming allows male birds to continue
singing
their costly songs even in the dark (figure 6). The urban heat island
also
causes birds to breed earlier and nest sooner. When not in breeding
season, a song
sparrow’s diet consists of weed and grass seeds and a few berries, in
addition
to insects. During breeding season, both parents feed the young a diet
made up
primarily of insect foods, such as beetles, flies, and caterpillars.
But if the
birds are not synchronized with the availability of resources, they are
out of
sync with food and nesting supplies, resulting in starved hatchlings,
according
to the National Wildlife Federation.
What results from the combination of light pollution and the urban heat island are modern generations of birds with stressful lifestyles. City birds sing at a more costly frequency and for longer periods of time. They mate during the night as well as the day, and across all seasons; this results in a shorter recovery time between each costly reproductive act. Ultimately, the stress of city-living will lower the immune responses of these birds and increase the incidence of disease.
Migratory birds on the Atlantic Flyway travel long distances via migration corridors from their breeding grounds in North America to their wintering grounds in the neotropics. Like local birds, the alteration of environmental factors leads to increased stress, which causes decreased natural immunity and increased susceptibility to disease. Their migration corridors are plagued by habitat loss and fragmentation, radio towers and tall buildings, and even disease (Aguirre, 2006).
Plants are affected as well, inevitably, because of their ecophysiological constraints. The increased nighttime temperatures are increasing respiration among plants, which ultimately result in increased CO2 (greenhouse gas) concentrations. Affecting the natural carbon balance in this way results in a positive feedback loop. Increased CO2 concentrations will tend to increase photosynthesis (which decreases CO2), but since nighttime is for respiration (which generates more CO2), the warmer nights are allowing plants to respire more. And increases in CO2 concentrations are making the atmosphere reradiate more radiation back to earth’s surface, resulting in a net warming urban island effect. A complementary positive feedback loop is how as it gets warmer, more people turn on air conditioners, which increase energy usage, which in turn contributes to thermal air pollution.
Some plants such as cottonwood have increased growth rates (Gregg et al., 2003), while others are flowering/budding earlier (Neil & Wu, 2006). As in the case with birds, if different species within the same habitat do not respond to artificial temperature changes in the same way, the loss of synchrony will break the vital links among interdependent species.
This loss of synchrony that results from the urban heat island has severe repercussions for community and food-web ecology. The web of relationships has very intricately coevolved between predator and prey. In this case, it is not a matter of removing a consumer or a terminal predator to influence bottom up or top down trophic levels; here, it is a matter of mismatching the carefully timed physiological processes within co-dependent species.
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The Restoration Plan, including
Benefits, Timeline, & Budget |
Noise Pollution – Acoustic adaptation gives song birds greater mating success (which leads to increased population density), but they also make them so specialized for mating purposes locally that they are not recognizable outside of their urban metapopulation (which leads a decreased genetic diversity). Such behavior-affected reproductive isolation isolates these city song birds, resulting in a type of undesirable subspeciation, and a reduction in diversity. The results of this threat are not immediately obvious, and since these birds are so common across the country, they have a conservation status of “least concern.” However, preserving genetic diversity of our city’s song birds through noise suppression will also provide services to New Yorkers as well. Central Park was deliberately designed by Olmsted and Vaux to provide a type of retreat from the foreseeable urban chaos. If the park within is as noisy as the park without, Central Park would have failed in its lofty design.
To suggest any
large-scale change
to Central Park is far too ambitious, so a gradual approach will work
well for
both wildlife and humans alike. This gives the song birds
time to gradually readapt to more “normal” noise conditions. There is
certainly
a very small chance of rerouting airways overhead or subways routes
that cut
the corners of the park, so I plan to gradually reroute automobile
traffic
within and around the park; in order to control the low-frequency noise
pollution of Central Park and gradually have the selection pressures
directed
towards the “normal” pitch of bird calls, automobile traffic must be
managed.
Phase
½: The riparian
woodland alongside the Pool, the Loch, and the Ravine will need to be
made denser
(figure 7). This will be a natural way of suppressing noise. I will
plant more of
the exact same species of trees as those already present, such as red
maple and
hickory. This phase will take many years to become effective in
suppressing
noise, but the plantings of saplings and slightly more mature trees
will take
place in six months. $10,000 will be allotted to the purchase of these
trees
and required materials, and the labor of planting will be kept at a
minimum by
utilizing the helpfulness of New York Park Restoration volunteers.
Phase I: Since the Ravine/Loch flows directly
under Glen
Span and Huddlestone Arches (figure 3),
this area is
most poignantly affected by noise-related stresses. I plan to gradually
close
down one of these two park drives. I have selected to keep Central Park
Drive, the
street through Huddlestone Arch, because
its
proximity to Lasker Rink/Pool already has
it
suffering from noise pollution. Park Drive S, the street that runs
through Glen
Span will be closed in order to maximize the reduction of noise in the
western
half of the North End. This will be accomplished over the course of one
year.
For the first four months, the street will be closed during off-peak
hours, and
then during the following eight months, the time slot where cars are
allowed
will be gradually scaled down until it is feasible to completely close
off Park
Drive S to all cars and trucks. The budget for this phase will be
$50,000 for signs,
public announcements, and the hiring of a crew to guide and redirect
cars
during the gradual close-down period.
Phase
II: (The
implementation of this phase is entirely contingent on the acceptance
and
actual feasibility of Phase I. After the first year, adaptive
management must
be called upon to readjust this phase as necessary.) The Loch and the
Ravine
are not located directly adjacent to any of the four major transverse
roads; in
fact, they lie nearly at the midpoint between Central Park North and 96th
Street. Thus I plan to eliminate the auto-use of the transverse road of
96th
Street.
Since the 86th
Street
cross-park road is the “mid-latitude” road, I would keep that one, so
as to not
too terribly inconvenience east-west commuters. Also, 86th
Street
runs through the less “natural” areas of the park anyways: the
Metropolitan
Museum of Art, the Police Precinct, and three playgrounds. However,
since this
road may have to be widened to accommodate all the redirected traffic,
this
comes as a sacrifice to the ecosystems south of the Reservoir and north
of the
Great Lawn, which will have increases in noise, auto-pollution, and
overall
disturbance; this includes the Arthur
Ross Pinetum. For that reason,
79th Street will remain as well, since it is near Belvedere
Castle, Swedish
Cottage Marionette Theatre, and playgrounds.
Similar to Phase
I, this phase will also take place over the course of one year,
beginning with
the gradual closure of
Phase III: (The execution of this phase is entirely subject to the completion of Phase I and II.) The auto traffic that circumnavigate the park (such as Fifth Avenue and Central Park North, South, and West – especially Central Park North, because that borders the Loch and the Ravine) will be reduced. This will be made feasible by redirecting usage to, and widening, parallel streets farther from the park (such as Columbus, Madison, 57th, and 110th). In doing so, I will temporarily be increasing noise pollution because of construction; I would like to start this restoration at a time when breeding is at a minimum so that the loudest sounds will be past by the time their official breeding season begins. So the timeline for this visionary phase will also be one year. During peak-breeding season, traffic will be gradually redirected to parallel streets farther from the park, and during off-peak breeding season, construction will begin and end. With the rerouting of transverse streets within the park and the streets that are parallel to the streets that circumnavigate the park, I will not only be managing noise pollution, but auto-generated disturbances as well.
The budget for
this phase will be
the greatest because of the sped-up timeline and the anticipated
opposition.
There will need to be funding specifically directed at the mitigation
of these
objections; this will include campaigns to educate the public on the
importance
of preserving genetic diversity and even the benefits of alternative
energy and
commuting methods. The budget will be $8 million, for the materials and
human-hours of de/re-construction of streets during one winter season.
Light Pollution – By decreasing light pollution, we can save
the biodiversity-ecosystem
function of pollination by nocturnal insects. This then also helps with
plant biomass
production, which further serves as suitable habitats for invertebrate
and
vertebrate species.
This is not only
a problem for
birds and plants; it is a problem for people as well. Light trespass is
a
general irritant for residents and especially for amateur astronomers. Glare,
in particular, is an issue in road safety, as bright and badly shielded
lights
around roads may partially blind drivers (especially those with high
astigmatism) or pedestrians unexpectedly, and contribute to accidents;
this has
even been termed “Disability Glare.” So the
benefits to residents and drivers make this an even
more relevant
restoration concern.
Since the light
posts have already
been eradicated along the Ravine throughout the woodland area, light
pollution
is only a major problem for the local birds and plants along the Pool
and
around Central Park. Those lights will be taken out and replaced with
(1) low
pressure sodium lights, which have an easy-to-filter single wavelength,
that
are (2) encased in “full cutoff” fixtures, which reduce sky glow by
preventing
light from escaping unnecessarily. Although these lights and light
fixtures
will cost money to purchase, they are both more energy-efficient so the
city
will actually be saving money
ultimately.
Each light will
be equipped with a
motion sensor that is keyed to higher magnitude ground movement, so
that light
will only come on when there is a jogger/runner or someone walking
through the
park at nighttime, for security reasons. The budget for this will be
$20,000.
Urban Heat Island – As I previously mentioned, the urban heat
island uses
the same language as the far more politically-charged global warming;
so in that
sense, this project must take into account climate change’s
implications for urban
restoration. Reducing the effects of the urban heat island is a benefit
for all
the species in an urban ecosystem, including its human residents.
Rising CO2
levels from emissions, land-use policies, and cement production are
already
contributing to a worldwide enhanced greenhouse effect, so it is
definitely not
advantageous to further increase CO2 levels on the microscale by forcing plants to respire more at
nighttime.
Much of the
urban heat island
effect is a result of cities lacking evapotranspiration, which is the
combination
of evaporation and transpiration of water into the atmosphere from
living
plants and soil. However, since Central Park has a sufficient amount of
vegetation
and standing water, it is cooler than its surround environ because of
its
relatively more abundant encouragement of evapotranspiration.
Much of the
surface materials of
Central Park North End are still absorbing solar radiation instead of
reflecting
it. So the surface thermal properties must be managed by replacing
black
asphalt with albedo-enhancing white concrete. This is a very disruptive
process, so it will also take place during the winter off-peak breeding
season,
along with the widening of transverse and circum-park streets. The
budget for
this will be $5 million, which includes materials, equipment, and
enough
human-power to accomplish this task within the given time frame.
|
Conclusions |
Future considerations – After the restoration project has been
implemented, we
should have a self-sustaining ecosystem. In order to test for the
effectiveness
of this restoration project, post-mortem, I will apply elements of the
Before-After–Control-Impact Studies.
·
Noise Pollution – Phylogenetic studies of the song sparrow (our
test
species) will be conducted to determine whether the narrowing diversity
has
been alleviated and whether genetic introductions of rural song
sparrows can
contribute to the city’s gene pool.
·
Light Pollution
and Urban Heat Island –
Plant
productivity and CO2 levels will be measured and correlated
to the
changes in temperature and light exposure. With healthier ecosystems,
we can
expect quality food and resources for nesting, breeding, and migratory
birds; migrant
species of the Atlantic Flyaway will be surveyed, and compared across a
long-term reassessment study.
Song birds that have conservation statuses
of “least
concern” and widespread plants that grow throughout the city may not
immediately incite the empathy of conservationists, especially when
their
conservation depends upon a large-scale, multi-million restoration
project
might, initially, negatively affect Central Park’s visitors and NYC
commuters. And
worse yet, the ecosystem functions are not immediately obvious as well.
While the
song birds are becoming less genetically diverse intraspecifically,
their populations are not necessarily declining, nor is there a decline
in
animal biomass production (even though the life span of an individual
song bird
has been shortened, their reproduction rates have not suffered a net
decrease).
And since there
certainly
is redundancy among the song birds of Central Park, even if there is a
decline
of one seed-pollinating song species, there will be others to replace
it. But
when considering the ecosystem functions that benefit wildlife species,
we must
also considering ecosystem services that benefit us, those that will be
designing, implementing, and funding restoration projects. As I have
shown, residents
and visitors to New York City can benefit from noise reduction,
unwanted glares
and glows, and a reduction of a city-scale anthropogenic warming. And
that makes
Central Park worth restoring.
|
References |
·
Alonso
Aguirre
(2006) “Disease Ecology and Migratory Species,” lecture given.
·
Henrik Brumm and Dietmar Todt (2002)
“Noise-dependent song amplitude regulation in a territorial songbird” Animal Behaviour
63:891-897.
·
Henrik Brumm (2004).
“Causes and
consequences of song amplitude adjustment in a territorial bird: A case
study
in Nightingales” Anais da Academia Brasileira de Ciências
76:289–295.
·
Neil
A. Campbell,
Jane B. Reece, Lawrence G. Mitchell ed. (1999) Biology 5th
Edition.
·
Charles
Darwin
(1874) “The Descent of Man.”
·
Esteban Fernández-Juricic et al. (2005) “Microhabitat Selection and Singing
Behavior
Patterns of Male House Finches (Carpodacus mexicanus) in Urban Parks in a Heavily Urbanized
Landscape
in the Western U.S.” Urban Habitats 3:49-69.
·
Jillian
W. Gregg,
Clive G. Jones, Todd E. Dawson (2003) “Urbanization effects on tree
growth in
the vicinity of New York City” Nature 424:183-187.
·
Travis
Longcore and Catherine Rich (2004)
“Ecological light
pollution” Frontiers in Ecology and the
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For more information, please also visit:
http://www.centralparknyc.org/centralparkhistory
http://www.centralparknyc.org/media/file/ag-birds1.pdf
http://www.sciencedaily.com/releases/2006/09/060901160821.htm
http://thenatureofnewyork.blogspot.com/
http://www.uvm.edu/%7Ermaurizi/oldStuff/urban.html
http://www.enviroliteracy.org/article.php/603.html
http://ive.cuny.edu/nynn/nature/life/birds.htm
http://www.newscientist.com/channel/life/mg19025483.700-evolution-gets-busy-in-the-urban-lab.html
http://en.wikipedia.org/wiki/Song_Sparrow