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Spatial Competition

Reading Inquiry -- Week 3

During the week 3 readings, I learned how spatial and temporal competition among species and individuals can be employed by designers to create dynamic, sustainable, and more expressive garden communities. Five specific things that I have learned this week include:

  • That how and where plants grow (spatial structure) and thrive is a complex adaptive system influenced by various variables including microsite climatic conditions, inter/intra-species phytohormonal feedbacks, and competition among individuals.
  • That in natural plant populations, individuals are genetically diverse even among species that spread clonally or produce genetically similar offspring.
  • That competition between individuals can be harnessed to induce competitive exclusion against unwanted species. It is possible to prevent unwanted species such as English Ivy from spreading into a designed area by planting more desirable species that consume the same resources and occupy the same niche. This can help reduce the time and effort required to maintain a landscape.
  • That communities are affected by present competition as well as past competition. The concept of regeneration niches states that whenever one plant dies, another plant will take its place. This new plant might not necessarily be of the same species as the one it replaces. This regeneration is affected by a multitude of conditions -- many of which have been influenced by the plants that lived before and the conditions that they were under.
  • That landscapes should be allowed to be dynamic and to vary in size, structure, and composition. In other words, populations should be allowed to change over time. This helps to create a feeling of place, increases diversity, and leads towards more resilient populations appropriate for the temporal and physical environment of the design.

I found these five concepts interesting. Together, they form a paradigm that shifts the design of garden communities (including the urban forest) from being static and expensive to maintain towards being dynamic and auto-regulating (Pennisi, 2020). This shift away from traditional gardening is beneficial as the health benefits that parks, and green spaces provide are greater in poor areas. In poor communities, municipal resources are likely to be already spread thin due to lower property taxes. The required maintenance of gardens and parks can take away resources from other critical services such as schools (Semuels, 2016). Under traditional gardening, annuals and short-lived perennials are some of the most common underbrush vegetation. When an individual dies, an opportunistic, wild, and unwanted species often grows in its place during the spring (Lovejoy, 2014). The large number of factors influencing whether an individual plant will thrive or perish heavily fluctuates over time. Gardeners must constantly remove weeds and replace plants. Under self-regulating designs, high levels of genetic and species diversity can ensure that desired species are always available to fill in gaps as they open under a wide range of conditions (Beck, 2013, Chapter 2). Plants that successfully compete for resources and propagate are often better suited for the local site's climate and soil conditions (Beck, 2013, Chapter 3). Unlike the creation of cultivars (such as described in the "The Schenley Park Tree Research Grove" reading), however, genetic diversity is maintained among individuals and in seeds stored in the soil. Biodiversity helps to decreases the risk of garden susceptibility towards disease and pests.

While self-sustaining gardens are cost-effective in Canada and the United States where wages associated with labor are high, the initial costs to design a garden ecosystem that mimics the structure of natural communities are higher than traditional garden designs. In places where labor is cheap, cost-benefit analysis may reveal that it doesn't make as much sense for individuals and municipalities to invest resources into reducing the amount of work required for maintenance. Traditional gardens often provide extensive employment for less-skilled and less-educated workers in impoverished areas such as the Eastern Cape Towns of South Africa who would otherwise remain unemployed (King & Shackleton, 2020, 2021). While morally acceptable in developed nations where alternative employment is widely available, reducing the number of low-skilled gardeners could arguably be considered unethical in developing nations with poor economies where work is already in short supply.

Critical Comment

With the week three readings, I've come to wonder how dynamic garden landscapes can be better popularized among popular fashion and opinion. Throughout high school, I worked for a couple of different landscaping companies. Each company I worked for was relatively dismissive of non-traditionally structured gardens. The common claim was that they were not as attractive as static landscapes (possibly because the companies wanted to remain in business, but ignorance and lack of formal education also likely play a role). While the readings have helped me apply knowledge from past courses to an alternative landscape design paradigm. I feel that unless this information gets spread into the industry and popular imagination, there is likely to be resistance to the widespread city-level adoption of diversity and competition into our gardens, parks, and landscapes. Public outreach may take the form of gardening seminars, pamphlets, and fliers, but I'm not sure how effective these mediums can be. My question for this reading inquiry, and what I'll be doing further reading on, is how to better reach and educate the public towards better, more sustainable urban forest practices such as those mentioned in this week's readings.    

Bibliography

Beck, T. (2013). Principles of Ecological Landscape Design. Island Press.

King, A., & Shackleton, C. M. (2020). Maintenance of public and private urban green infrastructure provides significant employment in Eastern Cape towns, South Africa. Urban Forestry & Urban Greening, 54, 126740. https://doi.org/10.1016/j.ufug.2020.126740

King, A., & Shackleton, C. M. (2021). Working in poverty: Informal employment of household gardeners in Eastern Cape towns, South Africa. Development Southern Africa, 0(0), 1--14. https://doi.org/10.1080/0376835X.2021.1940867

Lovejoy, A. (2014, April 25). Creating a Low-Maintenance Garden. FineGardening. https://www.finegardening.com/article/creating-a-low-maintenance-garden

Pennisi, B. (2020). Care of Ornamental Plants in the Landscape | UGA Cooperative Extension. University of Georgia Extension. https://extension.uga.edu/publications/detail.html?number=B1065&title=Care%20of%20Ornamental%20Plants%20in%20the%20Landscape

Semuels, A. (2016, August 25). Good School, Rich School; Bad School, Poor School. The Atlantic. https://www.theatlantic.com/business/archive/2016/08/property-taxes-and-unequal-schools/497333/