Asphalt Ecosystems: Native Landscapes as Urban Biodiversity Havens

Learn with Cristina Ayala-Azcárraga about the benefits and the impact of native plants in the urban environment in Asphalt Ecosystems: Native Landscapes as Urban Biodiversity Havens.

Currently, cities house 55% of the global population, and it is estimated that by 2050 this figure will increase to 68% (ONU-Hábitat, 2022). This accelerated urban growth presents enormous challenges for nature, such as habitat fragmentation, species loss, and resource depletion. In this context, urban green spaces have emerged as vital refuges for biodiversity, which struggles to adapt to environments dominated by concrete.

More and more cities are recognizing the importance of these spaces, which not only promote human health but also provide essential ecosystem services such as air purification, climate regulation, and support for wildlife (Cameron, 2016; Muñoz-Pacheco et al., 2022; Van Oijstaeijen et al., 2023). However, not all urban landscapes equally benefit local wildlife. The choice of plant species, whether native or exotic, has a direct impact on the ability of urban ecosystems to support biodiversity and ecological resilience.

Vegetación / Vegetation
Fotografía / Photography: Bruno Ngarukiye

Various studies highlight that native plants strengthen local biodiversity and improve ecosystem stability through coevolutionary interactions with native wildlife. These plants have developed specialized relationships with pollinators and other animal species, promoting greater ecological diversity and functionality (Archer de Carvalho et al., 2022; Prendergast et al., 2022). For example, some native plants produce nectar adapted to specific pollinators, while certain birds, such as hummingbirds, rely on flowers designed in shape and color to suit their feeding habits.

Despite these benefits, exotic species can also offer certain advantages. Some complement floral resources during times of the year when native plants are scarce, thus stabilizing pollination networks. For example, a study in Paris showed that exotic plants are crucial for providing nectar in the fall, when native resources decrease. While native species attract a greater diversity of pollinators in spring and summer, exotic species form more generalist interactions that can be valuable at certain times (Zaninotto et al., 2023).

Jardín para polinizadores / Garden for pollinators
Fotografía / Photography: Juris Freidenfelds

Additionally, in extreme urban environments, some exotic species show greater resilience, contributing to shade and thermal regulation in densely built areas. However, their proliferation can have negative consequences, such as the loss of biological diversity, disruption of ecological cycles, and homogenization of landscapes, which increases vulnerability to pests and diseases (Olden et al., 2004; Jarić et al., 2019).

The introduction of exotic species also contributes to biotic homogenization, reducing biodiversity. A study conducted in Montreal and Quebec revealed that highly urbanized areas have lower biodiversity due to the dominance of exotic plants, making ecosystems more uniform and less diverse. However, native species still maintain some functional diversity, highlighting the need to promote heterogeneous landscapes and manage green spaces properly to mitigate these effects and sustain greater ecological richness (Blouin et al., 2019).

Oasis urbano / Urban oasis
Fotografía / Photography: Pexels

With this in mind, it is crucial to adopt a balanced and mindful approach to urban vegetation management. The goal is not to indiscriminately remove exotic species, but to design landscapes that maximize ecological benefits. Prioritizing native plants is essential for conserving biodiversity and maintaining the ecological functionality of cities. These plants not only provide key resources for local wildlife but also promote complex ecological interactions that have evolved over thousands of years. By incorporating native species, we can create green spaces that beautify cities, strengthen ecosystems, and improve quality of life, ensuring a more resilient and sustainable urban environment in the face of climate change and urbanization.

Prioritizing native plants is essential for conserving biodiversity and maintaining the ecological functionality of cities. 

Parque japonés / Japanese park
Fotografía / Photography: Shernon Hague

Bibliographic references

Blouin, D., Pellerin, S., & Poulin, M. (2019). Increase in non-native species richness leads to biotic homogenization in vacant lots of a highly urbanized landscape. Urban Ecosystems, 22, 879-892

Cameron, R. W., & Blanuša, T. (2016). Green infrastructure and ecosystem services–is the devil in the detail?. Annals of botany, 118(3), 377-391.

Jari´c, I.; Heger, T.; Castro Monzon, F.; Jeschke, J.M.; Kowarik, I.; McConkey, K.R.; Pyšek, P.; Sagouis, A.; Essl, F. Crypticity in Biological Invasions. Trends Ecol. Evol. 2019, 34, 291–302.

Olden, J.D.; LeRoy Poff, N.; Douglas, M.R.; Douglas, M.E.; Fausch, K.D. Ecological and evolutionary consequences of biotic homogenization. Trends Ecol. Evol. 2004, 19, 18–24.

Prendergast, K.S., Tomlinson, S., Dixon, K.W., & Bateman, P.W. Urban native vegetation remnants support more diverse native bee communities than residential gardens in Australia’s southwest biodiversity hotspot. Biological Conservation, 2022rico, L., et al. Plant and microbial biodiversity in urban forests and public gardens: Insights for cities’ sustainable development. Urban Forestry & Urban Greening, 2018.

Van Oijstaeijen, W., e Silva, M. F., Back, P., Collins, A., Verheyen, K., De Beelde, R., … & Van Passel, S. (2023). The Nature Smart Cities business model: A rapid decision-support and scenario analysis tool to reveal the multi-benefits of green infrastructure investments. Urban Forestry & Urban Greening, 84, 127923.

Zaninotto, V., Thebault, E., & Dajoz, I. (2023). Native and exotic plants play different roles in urban pollination networks across seasons. Oecologia, 201(2), 525-536.