HomeMy WebLinkAbout2007 09 12 Hand Out given by Michael Mingea
September 12, 2007
HAND OUT GIVEN BY MICHAEL
MINGEA, CITY ARBORIST, TO
THE BEAUTIFICATION OF
WINTER SPRINGS BOARD AT
THE REGULAR MEETING ON
SEPTEMBER 12, 2007.
B 0 DIVERSI
in the
nv'ronment
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How a site is planned and landscaped can have
a significant impact on the local ecosystem.
daily with the site. Just as green design con-
siders the needs and comforts of humans in
the built environment, design for biodiversity
needs to consider those same issues for the
organisms that will make up the ecological
community at a site.
The design should allow for efficient and
comfortable movement through the landscape.
Areas of light and shade are needed, as well
as variation in the structure and topography
of the landscape. Successful promotion of bio-
diversity is seen in design schemes that pay
attention to the nonliving aspects of the land-
scape, such as rocks~
Biodiversity can be measured in many ways.
Two important metries are the variety of organ-
isms at a locality, referred to as alpha-diversity,
SOIL, SLOPE, TOPOGRAPHY, and hydrology
all affect the plant community at a site. The
plant community, in tum, affects the animal
community. Together, these elements make
up the biological community of a site-they
are the local ecosystem. Biodiversity is simply
the diversity of living things.
At the basic level, the more different types
of living things there are in one place, the
better and more diverse it is. Diverse systems
are more stable and resistant to pests and
weeds, and an increase in plant
diversity is also an aesthetic
benefit for those who interact
98 U R BAN LA N 0 J U N E 20 0 7
VICTORIA WOJCIK
and the variation between localities, called beta-
diversity. In the best-case scenario, both values
would be high, representing a region in which
there are many unique local sites.
The best ways to increase local biodiver-
sity include augmenting the number of plant
species at a site, using locally native plant
species, and focusing on plants that are im-
portant resources for local wildlife. Choosing
plant species that attract beneficial insects
and birds is the next step. Although having a
variety is better, a well-chosen single-species
planting can do a lot to attract and support a
range of birds, insects, and other organisms, as
well as a landscape that comprises rocks and
logs that can be used as potential homes by
these organisms.
Trees and shrubs that bear fruit provide a
benefit to both birds and bees. When in .
.
bloom, their flowers attract pollinating insects.
The resultant fruit serves as a food source for
many birds and small mammals. Wild sun-
flowers (Helianthus spp.) and other composite
asters are a great choice for attracting a wide
range of bees, butterflies, and birds through-
out the season. Their composite structure and
disclike shape provide larger-bodied bees ant
butterflies a secure landing pad. Small bees
and hummingbirds can easily forage on this
plant as well. later in the season when s~
develop, they become a food source for othet
birds and small mammals. Penstemons (fen'
stemon spp.), phacelias (Phacelia spp.), and
sages (SaMa) all have tubular flowers that art
used by butterflies, hummingbirds, and bees.
Penstemon and SaMa plants, in particular,
have a wide range of species, varieties, and
--.
cultivars that can meet the needs of any
design. The benefit of sage species is their
perennial nature. They can become perma-
nent features of a landscape plan that will
augment the local biodiversity of the site with-
out much care. Rhododendron and Sambucus
are also great attracters of all groups. The key
is to look for a locally native species of these
plants because this will be the best plant for
the local wildlife.
When it comes to green building certifica-
tion, biodiversity is not rewarded as heavily
as using sustainable harvested materials and
energy-efficiency measures. But choosing to
increase the biodiversity of a site could raise a
structure from one certification level to another.
Of the 69 points available under the latest
Leadership in Energy and Environmental Design
(LEED) 2.2 certification, only two-within the
Sustainable Site Credit-are gained through
directly providing landscape elements that
can increase biodiversity. Sustainable Site
Credit 5.1 deals with the creation of a habitat
or the mitigation of a removed habitat. Some
reference information on endangered species
is provided, which is commonplace these
days in landscape management There are
sets of rules and regulations such as the
Endangered Species M. that outline provisions
to protect these organisms. The mitigation of
habitat also is clearly outlined with a set of
guidelines that dictate what kind and how
much is needed. The promotion of general
biodiversity is less clear and more effort has
to be made at the site-specific level to
achieve this goal. The task is, however, sim-
pler than it seems and has been successfully
achieved, at times unknowingly, in urban
areas and design projects across the globe.
Sustainable Site Credit 5.2 focuses on
open-space provisioning. This one is tricky
because creating a single-species-dominated
open space, such as a large lawn area, quali-
fies for a credit, but does little to help increase
biodiversity. This can be easily overcome, how-
ever, by adding bordering vegetation to the
edge of the property. Other ways to increase
biodiversity in open spaces could include a
wildflower field or a variety of native grasses.
As suggested in LEED, native species should
always be specified.
A vacant lot (below) with an effect diversity of nearly zero, was planted with some
70-plus plant species and subsequently attracted 3S-plus bee species, as well as
numerous beetles, spiders, moths, flies, and birds (above).
JUNE 2007
99
URBAN LAND
Indirectly, two other LEED credit require-
ments can be met to maximize biodiversity
at a site. Water Efficiency Credits 1.1 and 1.2
focus on reducing the need for irrigation by
half; using native species that can best toler-
ate local precipitation pattems will accomplish
this goal. A subset of more tolerant native
species will require no additional watering,
eliminating the need for any irrigation.
Innovation in Design (lD) Credit 1 is an
open-ended credit that invites innovation in
technology and theory to the sustainable
building process. Its intent is to reward ex-
ceptional performance in any existing credit
to sustainability strategies not outlined in the
current LEED program. A developer could pro-
pose an ID credit for providing a habitat that
supports a vital community of plants and ani-
mals through a landscaping and management
plan. Under a correctly outlined design plan,
there is the potential that all five credits-
SS 5.1 and 5.2, WE 1.1 and 1.2, and ID 1.1-
could be achieved providing an ambitious
project with five LEED points.
Surprisingly, private individual landowners
who have a personal interest in gardening
have been the most prolific in producing
biodiverse sites. Studies of urban garden
ecosystems in North America and Europe
have documented hundreds of insect species
associated with diverse private gardens. On
average, biodiversity is higher in urban areas
in Europe and North America than in the adja-
cent landscape due to the planting of exotic
species and basic personal gardening pat-
tems. English author and scientist Jennifer
Owen studied the diversity of species that
visited her tiny Leicester garden over the
course of 15 years. To her surprise, and to
100 U R BAN LA N 0 J U N E 2 0 0 7
Applicability
djverse and supports local species
aside forthepurpose of creating
ts and animals.
,at are "ppfopriate fur increasing
te also locally adapted to water
these. plants Will not require
ts.
dscape management plan that
izing biodiversity may qualify as
innovation.
that of many of her colleagues, she has
accounted for more than 25 percent of the
known national diversity in butterflies, moths,
and beetles. She also noted 55 species of
birds and seven species of mammals.
Urban ecosystems are starting to be stud-
ied more extensively and pattems of biodiver-
sity are beginning to emerge. It is clear that
the urban environment is more biodiverse
than was originally thought. The next step is
the conscious integration of this knowledge
into green construction, as well as the incor-
poration of appropriate species to promote
functional biodiversity. Regionally appropriate
species will interact with the local ecosystem
and add benefits; diverse exotic species will
do little to interact with the local ecological
communities.
Though many projects set aside space for
habitats, few have the explicit goal of design-
ing for biodiversity. This is not surprising, as
there is little in the current commercial litera-
ture that outlines the procedures one should
take to achieve this goal. Much of this infor-
mation still rests within academic joumals-
where there has been a recent movement
toward assessing and analyzing the health
of ecosystems within urban areas. The tenta-
tive conclusion in the academic literature is
that conserving and promoting biodiversity
in the built environment is a workable con-
cept that has potential.
Research conducted at the University of
Califomia at Berkeley by the Frankie Bee Lab-
oratory tested the idea of building a diverse
habitat for the purpose of attracting bees into
an urban residential area. A site measuring
only 900 square feet (83.6 sq m) attracted
v
BIODIVERSITY in the BUILT ENVIRONMENT
more than 35 species of bees within two
years of planting. A team of Rorida scientists
conducted a study of the bird diversity both
before and after a new community develop-
ment preserved a remnant habitat and added
native plantings, concluding that bird diversity
at the site increased after development
In Europe, most notably Scandinavia,
Switzeriand, and England, green roofs have
been noted to be venues for significant biodi-
versity within the urban environment. In addi-
tion to the originally planted floral species,
insects, birds, and small mammals and rep-
tiles have been recorded on rooftops. Simi-
larly, the green roof on the Gap headquarters
in San Bruno, Califomia, has been colonized
by various forms of local wildlife. This positive
occurrence helps us to think more deeply
about the nature of landscape planning as we
move beyond aesthetics and water efficiency.
Recently, the London Development Agency
in England issued Design for Biodiversity,
which describes how planning for a biodiverse
urban landscape can fit within the planning and
development process. Highlighted projects are
the green roofs at the Laban Centre and the
Creekside Educational Trust-both planned with
the goal of maximizing biodiversity. They not
only incorporated varied topography to increase
microhabitats, but also paid close attention
to the diversity and composition of the floral
resources planted to ensure food or shelter for
local wildlife species. A highlight of these proj-
ects was a "nooks and crannies" approach to
the landscape that promoted critters.
Few development projects have been com-
pleted with the stated goal of promoting bio-
diversity. The landscape and design firm Rana
Creek in Carmel Valley, Califomia, considered
increasing biodiversity as an essential part of
creating green buildings. Rana Creek focuses
on green roofs and native plant landscaping,
and has made an effort to go beyond what
has been outlined in LEED in terms of increas-
ing biodiversity in its projects. The firm is cur-
rently installing a green roof at the Califomia
Academy of Sciences building, under con-
struction in San Francisco's Golden Gate Park
and scheduled to open next year. The roof
will be planted with a variety of native plants
known to attract bees, flies, moths, and but.
terflies, one of which, the Bay Checkerspot
butterfly, is on the state's endangered species
list. Other biodiverse green roofs are in the
planning process, and include a potential net-
work of green roofs in the south San Fran-
cisco Bay that would also provide habitat for
the Bay Checkerspot.
Sites need not be vast and expansive to have
a major impact on the local ecology. What land-
scape designers need to focus on is the micro-
habitats that exist, or can be created, on the site.
A set of guidelines developed specifically to draw
a diversity of bees to a small garden site, for ex-
ample, can be applied to other organisms with
modifications made in the plant species:
[> Aim for patches that measure 13 feet by 13
feet (4 m by 4 m);
[> Choose plant species known to be attrac-
tive or essential to individual organisms;
[> Plant ten or more species of plants;
[> Provide vertical structure in the landscape;
and
[> Leave soil bare in some areas to increase
the variability in microhabitats.
Biodiversity is an important factor in the
healthy functioning and sustainability of an
ecosystem. Developing greener cities calls for
an understanding of how these ecological
communities interact. Efforts to "green" the
built environment have started with the core
of the constructed structure. Moving outward
from the core, through the shell, and to the
junction of the building with the natural envi-
ronment is the next big step. U.
VICTORIA WOJCIK is a PhD student at the Univer-
sity of Califomia at Berkeley, studying the effect that
the urban landscape has on native bee species and
how this landscape can be managed to increase the
populations of these important organisms.
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