How do local gardeners teach us about climate change impacts in the Mediterranean region?

Threatened urban gardens’ ecosystem services in Cataluña.

At the beginning of April 2021, I started going to Sant Cugat del Vallès, a municipality located in the metropolitan area of Barcelona, Spain, to collect LICCI data for my master thesis. The main focus of my research was to understand the climate change impacts that local gardeners are perceiving through time and how they are adapting to that. To do so, I conducted 20 in-depth semi-structured interviews in the urban gardens of Sant Cugat, especially targeting older gardeners with continuous and significant dedication to the garden, as well as informal conversations, and non-participant observation.

View of L’Ateneu urban Garden

Sant Cugat del Vallès is a city located 134 meters above sea level and in the full domain of the Mediterranean coastal climate. This site was selected to be my case study due to its long-term urban food garden history and municipality support to urban food gardening projects, its agrarian past, and its climatic characteristics in terms of being located in a climate change hotspot region. In the context of Climate Emergency Plans disseminated around the globe, the City Council of Sant Cugat promotes urban agricultural aiming to enhance environmental, cultural, social, educational, and health benefits in the municipality. The urban gardens of Sant Cugat are divided into three categories: school gardens, social gardens, and community gardens for organizations. In this study, we choose to collect data in four relatively homogenous urban food gardens belonging to the category of community gardens described by the municipality, prioritizing those that were created the longest ago.

The interview with local gardeners followed a guideline aiming to understand the environmental changes that they had noticed in the local ecosystem focusing on those affecting urban gardens. After identifying the climate change impacts, I associated this information with the categories of The Economics and Ecosystems Biodiversity (TEEB, 2011, p.3-4) to identify which ecosystem services of urban gardens are being directly and indirectly affected by reported LICCIs.

In the four urban gardens that I conducted the interviews, the gardeners reported several environmental changes in the climatic, physical, biological, and human systems that are currently affecting the garden activity as well as several adaptation strategies they are performing to deal with that. Specifically, I identified 30 LICCIs, six ecosystem services affected by LICCIs, and nine local adaptation strategies.

Local Observations of Climate Change Impacts and Affected Urban Gardens Ecosystem Services

The results of this research show that local gardeners are perceiving changes in the climatic system the most, such as an increase in the mean temperature, increase in the frequency of heavy rainfall events, and changes in the transition between seasons in the sense that nowadays is more irregular than in the past. The reported observations in the climatic system perform a “cascading” effect on the following systems, affecting urban gardens productivity and human livelihoods. For instance, in the physical, biological, and human systems the most reported observations were respectively that now there is a reduction in the number of snowfall events, now there are fewer insects such as bees and ladybugs, and that now it’s possible to extend summer crops until October. Asking gardeners for the possible drivers for those observations, they mentioned climatic factors such as increased temperatures in winter, spring, and summer season but they also mentioned non-climatic factors such as globalization and pollution, evidencing a combination of complex and interacted pressures. Additionally, local gardeners associated climate change with relevant changes such as that now some vegetables are blooming before, which sometimes results in harvest loss, and that now there are more allergies and intolerances, affecting human health.

In parallel, following the TEEB Manual for Cities (2011) categories, the reported LICCI observations provided by gardeners resulted in six ecosystem services that are currently being threatened to be fully provided to society. I found that the food provision is the ecosystem service impacted by more reported LICCIs, following for maintenance of genetic diversity, biological control, erosion prevention and maintenance of soil fertility, recreation, and mental and physical health, and pollination.

Local Adaptation Strategies to deal with Climate Change Impacts

Aromatic plants combined with food to attract biodiversity in Mira-sol urban garden

Gardeners have been implementing new management practices to adapt to environmental changes in the area and improve the efficiency of ecosystem services of urban gardens that have been affected by LICCIs. Those are mainly related to irrigation, pest treatment, maintaining and attracting biodiversity, heat protection of the soil, and crops calendar.

Basically, in response to LICCIs, gardeners are irrigating the crops more than they used to, are using new techniques to prevent and treat pests such as the potassium soap, are now using a wood structure called “insect hotel” to improve biodiversity, and are using the mulching technique to cover and protect the soil against increased temperatures and decrease in the mean rainfall. Interestingly, gardeners also reported that they are changing the time that they plant summer crops, advancing it in about 40 days. This is in response to higher temperatures in the spring season, which makes it possible to plant summer crops in spring and sometimes have two harvestings.

In conclusion, urban gardens, increasingly affected by environmental changes, became a hotspot to identify climate change impacts in urban environments. At the same time, these community spaces are an essential strategy in urban planning and design to meet the paradigms of nature-based solutions to mitigate climate change in peri-urban sites. Therefore, the range of pressures imposed by climate change that urban gardens are facing will determine the success of this valuable green-infrastructure strategy in urban management. In this way, local knowledge has an essential role in contributing to climate change research and policymaking to enhance the provision of several benefits associated with urban gardening activity such as food provision, contact with nature, and mental and physical health, and thus increasing resilience capacity-building to deal with climate change shocks and stresses that we are already facing.

Júlia Mattos (Mastert student)