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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 "'.~ " 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. J U N E 2 007 U R BAN LA N 0 101