In today’s society, we can witness the increasing spread of solar panels in many regions. It is widely known that these installations can supply clean energy. However, beyond serving as energy providers, they have an additional mission: to protect the natural environment. For instance, facing the continuous decline in the number of crucial pollinating insects, many developers have begun to plant native wildflowers around the arrays of solar panels.
In a comprehensive study, researchers spent five years observing that planting native wildflowers around these facilities could effectively increase the number and diversity of pollinating insects. This practice not only benefits the ecology around the solar panel arrays but also brings about what is known as the spillover effect: that surrounding farmland also benefits. This study was published in the journal Environmental Research Letters.
From 2018 to 2022, landscape ecologist Leroy J. Walston and his research team at Argonne National Laboratory in the United States conducted regular surveys of two solar photovoltaic stations in southern Minnesota. These stations cover tens of thousands of square meters. The researchers recorded the number and types of pollinating insects attracted by the wildflowers, which included bees, beetles, butterflies, and moths. The results showed that the number of pollinating insects near the solar photovoltaic stations had significantly increased. In stark contrast, in other areas of the United States, the numbers of these beneficial insects are actually in continuous decline.
There are many factors leading to the decline in pollinating insect numbers, including the widespread use of pesticides, the emission of greenhouse gases, and the destruction of habitats. For example, over the past twenty years, the population of monarch butterflies in the United States has plummeted by 80%. Additionally, according to a 2017 report from the Center for Biological Diversity in the United States, about a quarter of native bee species are at risk of extinction. If this trend continues, the US ecosystem and agriculture could suffer catastrophic harm. It is known that 75% of North American plant species depend on pollinating insects for survival.
It is noteworthy that to achieve energy goals, the US federal government plans to transform tens of thousands of square kilometers of land into solar photovoltaic stations, and over 80% of the projects will involve the use of agricultural land. Planting native wildflowers around these solar stations becomes a possible strategy to save pollinators in danger.
Furthermore, Walston and his research team found that as goldenrods bloomed around the photovoltaic stations, beetles from the family Chrysomelidae, named after this flower, gathered. As various types of flowers bloomed one after another, a symphony of diverse insects came alive. The increase in the number of native bees was particularly astounding—at the end of the study, their numbers had grown by 19 times. The population of monarch butterflies also increased, gliding between the solar stations, flaunting their vibrant wings. In fact, soybean fields near the solar stations welcomed more bees, twice the number found in distant soybean fields, bringing benefits to the farmland close to the photovoltaic stations, equivalent to the farmland surrounding protected land.
Ecologist Zara Dowling is working on a special project: promoting the dual use of photovoltaic power generation and plant cultivation in Massachusetts, USA. She noted that although the benefits of wildflower planting have been proven, photovoltaic power station owners are still hesitant due to concerns about the cost of planting wildflowers and potential risks. However, Dowling believes that, with an increase in future incentive policies and the emergence of more research findings, this environmentally friendly practice can become widespread without much effort. She says, “As far as I know, if this method is economically viable, many people are willing to try it.” Even in other environmental conditions, such as the desert areas of the Southwest, the effectiveness of this method requires further study, but in places like the Midwest of the United States, planting wildflowers seems to be a beneficial choice. The situation in these areas shows that once wildflowers are planted near photovoltaic power stations, pollinators will quickly be attracted.
In this land increasingly covered by solar panels, developers have begun to plant native wildflowers around photovoltaic arrays, offering a new approach to engage residents and protect the natural environment. A five-year study published in the journal Environmental Research Letters shows that planting wildflowers can significantly increase the number and diversity of pollinators, and even benefit the surrounding farmland due to this so-called “spillover effect.” Between 2018 and 2022, landscape ecologist Leroy J. Walston from the Argonne National Laboratory and his team regularly surveyed two photovoltaic power stations in southern Minnesota. They monitored and recorded the variety of pollinators attracted by wildflowers, including bees, beetles, butterflies, and moths. The results showed a significant increase in the number of pollinators near the photovoltaic power stations, contrasting the declining trend of pollinators in many other regions.
The reasons for the decline in pollinator numbers are varied, with common ones including the use of pesticides, greenhouse gas emissions, and habitat destruction, among others. For instance, over the past 20 years, the number of Monarch butterflies (Danaus plexippus) within the United States has plummeted by 80%. Moreover, according to a 2017 report released by the Center for Biological Diversity, nearly a quarter of native bee species face the risk of extinction. If this trend continues, it could have a disastrous impact on the ecosystems and agriculture of America. Pollinators play a crucial role in the growth of plants, affecting over 75% of plant species in North America. In the pursuit of energy goals, thousands of square kilometers of land will be developed to build photovoltaic power stations, and most of this will likely be land that was originally used for agriculture.
Planting vegetation around solar power stations might become an important initiative to save threatened pollinating insects. Walston and his research team discovered that when a species of goldenrod bloomed around the solar panels, it attracted swarms of beetles from the family Lampyridae, which are named after these yellow blossoms.
Later, as more flowers opened one after another, a symphony composed by various insects began to resonate. Particularly noteworthy was the significant increase in the local bee population—at the end of the study, their numbers had surged by 19 times. The numbers of monarch butterflies also increased; they fluttered their colorful wings and danced around the solar power stations.
In fact, soybean fields adjacent to solar power stations attracted more bees, with numbers being twice that of fields further away from the stations. This means that the agricultural output of lands close to solar facilities, which participated in conservation plans, showed no difference compared to others.
Zara Dolin, as an ecologist responsible for overseeing and guiding the combined solar power and plant cultivation projects in Massachusetts, believes that despite the solar developers’ slow adoption of wildflower planting strategies—partly due to station owners’ concerns about the risks and costs involved—the practice is hopeful to be widely adopted with the introduction of incentive policies and further supportive research.
“As far as I know,” said Dolin, “many people would be willing to adopt this method as long as it ensures the balance of expenses and income.” Although it remains to be seen how effective this idea may be in other regions of the United States, like the deserts of the Southwest, Walston still believes that at least in the midwestern United States, “if we plant wildflowers around solar power stations, pollinating insects will naturally come to these places.”
