“Classifying and valuing ecosystem services for urban planning” by Erik Gómez-Baggethun and David Barton presented a different perspective on urban plant life. While aesthetics plays a role—increasing property values for tree-lined streets and park views—urban plants have very different jobs and expectations than their country counterparts. For instance, Baggethun and Barton document how urban plants purify the air, which can reduce health care costs, as well as mitigate water runoff and heat transfer, which may reduce other city expenses not often considered in urban planning. Plants around cities can offer a buffer to protect from natural elements, including storm surges. Urban plants offer green spaces to migrating animals and birds, which not only increases biodiversity, but their excrement can be potent fertilizer and germinate seeds eaten elsewhere. Finally, urban gardens may provide more than sustenance, but a sense of community that draws people together for a common cause where rural agriculture may be run by a corporation or single family.
The demands on city plants, similar to humans, requires adaptability and ability to survive intense environments. Covered in Wild Urban Plants of the Northeast by DelTredici, non-native species found in urban environments may be the only plant life that can survive and thrive in variable climates, precipitation, sunlight and potentially lack of soil or groundwater inherent to urban landscapes. These species were introduced via Europe and Asia to North America over hundreds of years and joined our own species of plants that are capable of adapting quickly. If it were not them to colonize these areas, including sidewalk cracks, abandoned plots, or neglected rooftops, what other plant life would be capable? These plants, perhaps unwelcome for their aesthetic appearance, help cleanse the air, give sustenance to urban animals and insects, and fill in a biotic gap that humans have created by removing native species. The Tree of Heaven, aka the ghetto palm, is able to grow in places made inhospitable to the native plant life by urbanization, but it is not displacing any pre-existing plant life, it is filling in a niche left empty by urbanization. These plant species have the ability to adapt to the challenges we created, not only growing, but becoming the primary plant life outside of human cultivation. We may consider the areas they colonize abandoned, or a wasteland, but they add to the biological diversity lacking in cities.
This is the same way that Emma Marris in Rambunctious Garden views “novel ecosystems” which are a combination of native and non-native species that have grown, most often without human maintenance. These areas may comprise up to 35% of the non-glaciated landscape, and perhaps the majority of urban and semi-urban areas. We should study these areas more thoroughly to understand their unique diversity, and especially what makes them work together, to assist our understanding of re-growing areas that have been devastated by human or natural disturbance. Perhaps we should consider introducing invasive species that might thrive in ruined environments, such as reclaiming the rainforest, which has been clear-cut for agricultural use and animal grazing. Although this might not be the final result, it might help nature get a leg-up in reforestation and soil-generation that could not occur if left only to native species and would otherwise take significantly longer. The “invasive” species might attract and give shelter to other wildlife, insects, animals and plants, which might not have the ability to exist alone in a bare landscape.