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The Unintended Consequences of Pollinator Gardens

Pollinators are essential organisms to the health of most ecological communities and aid human populations with producing vital necessities such as crops, clothing, and livestock. Unfortunately, along with many other organisms, pollinators are extremely vulnerable to our world’s increasingly volatile climates and rising temperatures, and the influx of invasive species brought about by global trade has put these foundational species at risk of significant population decline, and even extinction. In recent years, interest in pollinator health and restoration has grown within the general public. Beginning with the popular “Save the Bees” campaign, peoples’ love and respect for pollinators began to move beyond sharing trendy infographics and into their own homes, or more specifically, their own gardens. 

One of the largest threats to pollinators remains loss of habitat. The major contributor to this habitat loss is the clearing of land for developmental purposes and industrial monoculture crop production. When land is cleared, so are the native plants that historically covered the ground and serve as primary producers for the ecosystems they inhabit. This has led many people who have become enamored with the small pollinator species to take matters into their own hands by doing away with their single species grass lawns and diversifying them with wildflowers and other plants that attract pollinators such as birds, bees, and bats. These urban and suburban pollinator oases aim to rehabilitate pollinator species from the ground up, by providing them with places for food, shelter, rest, and breeding grounds. 

While pollinator gardens are extremely thoughtful and well intentioned demonstrations of activism, they often come at the detriment of local ecosystems and biodiversity. To start, many people fail to do the appropriate research on native plant life and plant harmful and invasive species in their gardens. Oftentimes, seed packages for wildflowers contain a melange of flowers from various states and regions. Additionally, online seed retailers fail to accurately provide information on the types of seeds their packs contain, which has potential to ignite ecological disasters.

Moreover, many of the plants that end up in these gardens are weeds, or unwanted plants, which grow at extremely rapid rates and reproduce even faster than typical angiosperms. If not contained, the species can spread outside of their planted region and push out native species of plants which are no longer viable due to the influx of new plants. Even if one goes to great lengths to physically contain these plants, it is nearly impossible to stop their spread through wind, and ironically, pollination. This can prove to be particularly harmful to plants in urban areas. Urban cityscapes tend to lack ground space for seeds to settle, increasing the effects of competition on a plant’s ability to thrive within the ecosystem. Airborne seeds and pollen that migrate from poorly contained urban and suburban pollinator gardens are able to settle and take hold in even the smallest of crevices within sidewalks. As they multiply, they begin to slowly push out native urban plants, and ultimately lead to their extinction. Invasive plant life in cities is particularly dangerous, as it is already a fragile ecosystem that is exposed to extreme change due to human interactions and pressures placed on the habitats.

A lesser understood effect of pollinator gardens is their tendency to attract the wrong kinds of pollinators, which can oftentimes adversely affect other conservation efforts. In urban areas in particular, pollinator gardens are frequented by an invasive species known as the Paper Wasp. These wasps are attracted specifically to monarch oriented gardens, and will set traps for monarch larvae amongst milkweed leaves. Because milkweed gardens are perfectly oriented to monarchs’ needs, they provide a limitless feeding ground for the wasps. Additionally the invasive Paper Wasps predation on the monarchs is not a part of the normal ecological processes, and can have extreme consequences on their populations. Thus, pollinator gardens have the potential to exacerbate the threats that have already been posed to these vulnerable populations by other anthropogenic factors. 

While the possible consequences of planting a pollinator garden may be overwhelming, it is still possible to create a healthy and safe environment for native pollinators to thrive. To start, it is important to research wildflowers and plants that are native to the area in which the garden will be planted. Additionally, it is important to buy seeds and plants for a garden from local nurseries rather than online vendors, as this provides the opportunity to ask questions about local species and ensure the appropriate plants are being bought. There should be a wide variety of plants planted to ensure a diverse selection of native pollinators are drawn to the space. At the same time, it is best to avoid modern plant hybrids, which have been bred to increase bloom and have less pollen and nectar available to the animals. It is also important to prioritize weed growth over mulching and fabric lawns, in an effort to maximize the food supplied to the pollinators. When curated with these guidelines in mind, pollinator gardens have the ability to improve the quality of pollinator lives, and aid in the efforts to increase their populations.  

Though poorly planned and planted pollinator gardens pose many threats to pollinator populations, these gardens can be extremely helpful methods in aiding the natural ecological community. The best way to ensure the safety of ecosystems while aiming to preserve and protect pollinator species is to do thorough research on native plant species, and ensure that the right species are planted in local gardens and pollinator gardens alike. Pollinator health is a direct reflection of the health of our own ecological communities, and without their help humans would be at a loss for many desired and essential products. In order to help restore their habitats and communities, it is important to channel good intentions through careful planning, research, and consideration of how the actions one takes may result in detrimental ecological consequences. 

Sources:

Baker, A.M., Potter, D.A. Invasive paper wasp turns urban pollinator gardens into ecological traps for monarch butterfly larvae. Sci Rep 10, 9553 (2020). 

Johnson MT, Thompson KA, Saini SH. 2015.  Plant evolution in the urban jungle. American Journal of Botany 102:  1951– 1953.

Planting Pollinator-Friendly Gardens. Penn State Extension. 2018. 

van Kleunen M, Dawson W, Essl F, Pergl J, Winter M, Weber E, Kreft H, Weigelt P, Kartesz J, Nishino Met al. 2015.  Global exchange and accumulation of non‐native plants. Nature  525:  100– 103.