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Insects: making a buzz about green roofs

by Matt Downs

In his latest Academic Corner column, Dr Tom Young of TEP focuses on entomology and the impact of green roofs on insect habitats. To help find out more about the role of entomologists  and what can be done to improve green roofs as habitats for insects, he taps into the knowledge of expert Dr Konstantinos Tsiolis of Pollinating London Together…

Dr Tom Young, Blue-Green Infrastructure Associate at The Environmental Partnership (TEP).

Green roofs can provide fantastic habitat for insects in urban areas. With this in mind, GRO has recently helped to publish a children’s book on this topic in collaboration with Tales from Mother Earth, which is available to buy at talesfrommotherearth.co.uk. However, this is an area I know very little about, and so to explore this topic further I thought I would enlist the help of Dr Konstantinos Tsiolis, who is a very knowledgeable pollinator ecologist and entomologist, who works for Pollinating London Together. 

The academic literature on the topic of insects and green roofs is still relatively sparse, but has improved in recent years as the role of green infrastructure in urban ecology becomes better known.  

In general, the consensus is that green roofs, compared to normal roofs, attract significantly more biodiversity to cities, which includes birds, insects and other invertebrates (Wooster et al. 2022). This can have knock-on effects across the food chain. For example, a study on a large green roof in New York found that bat feeding activity on the roof was strongly correlated with the presence of a certain type of moth. This moth was attracted to the green roof due to the vegetation and habitat provided, which in turn attracted the bats, providing them with a valuable food source (Partridge et al. 2020).

However, all green roofs are not the same, and changes in vegetation type, vegetation coverage, substrate type and additional microhabitat features all combine to determine how effective green roofs can be for insects (MacIvor & Ksiazek 2015). In addition, the size of the green roof and type / quality of surrounding habitats all play a part (Ksiazek-Mikenas et al. 2018), and native plants have been shown to increase insect abundance on green roofs (Fenoglio et al. 2023).

To better understand how people become entomologists and what can be done to improve green roofs as insect habitats, I asked Dr Konstantinos Tsiolis a few questions about his career and work with Pollinating London Together (PLT).

Tom Young (TY): What is your background?
Konstantinos Tsiolis (KT): I come from a small rural community in Cyprus where the region’s primary income was traditionally from crops such as hazelnuts, almonds, vines, cherries and apples. I have grown up working on our family farm, helping cultivate crops and selling our produce at various markets. 

The quality of our family life was always dependent on the yield of our farm, and I have experienced first-hand the frustration and negative financial impacts of low yields at times. My parents have only completed primary education but are rich in valuable empirical farming skills and knowledge. However, I realised that the lack of access to scientific knowledge was a limiting factor to sustainably successful farming practices. Having realised the value of science and education, I decided to enrol in higher education in the UK to gain knowledge and skills which I could use to contribute towards my passion for ecology and agriculture. 

One of the areas that immensely fascinated me during my undergraduate studies was pollination ecology. I was amazed that approximately 70% of 270 bee species in the UK are ground-nesters (Else & Edwards 2018), and several are considered good crop pollinators. For instance, solitary ground-nesting bee species are the UK’s most economically important pollinators of apple crops (Garratt et al. 2016). Nevertheless, little is known about where they nest in agricultural landscapes and their specific nesting habitat preferences. The eagerness to study them and discover more about their biology led me to study their nesting preferences in commercial fruit orchards for my Master’s degree and PhD. Since the spring of 2022, I have been working for Pollinating London Together (PLT), assessing the pollinator and pollinator-friendly planting diversity in the City of London and adjacent areas, and spreading awareness of pollinator diversity and importance. 

TY: What is an entomologist?
KT: Entomologists study insects, either amateur, as a career or both. Over half of the described two million living species are insects and have been around for over 350 million years. Insects play a crucial economic, ecological, and public health role. Some insects are vectors of many severe plant, human and animal diseases. In agriculture, they can cause many problems as pests, but they can also be very beneficial as decomposers, pollinators, and natural predators. Understanding the biology and ecology of insects enables entomologists to control harmful insects and promote beneficial ones. 

TY: What is Pollinating London Together? 
KT: Pollinating London Together’s mission is to enhance green spaces in central London so that natural pollinators can thrive and their habitats can be enjoyed by everyone, starting in the City of London. The vision is to create a template for change and action through leadership that can be implemented in urban environments across the UK.

PLT’s objectives are: 

• To redress the decline in pollinators in urban environments by promoting action to increase pollinator-friendly planting and habitats, starting in the City of London and its immediate environs.

• To raise awareness of the human benefits of pollinators and pollinator-friendly planting across the wider population of residents, workers, and organisations, starting in the City of London. 

• To inform and encourage companies, organisations, and individuals to make meaningful decisions to make this happen.

To achieve its objectives, PLT engages in a variety of activities to raise awareness, educate, and influence action that will help pollinators and their habitats thrive. Specific activities include:

• Creating new networks for positive action, change, and influence;

• Running a green space habitat review programme for outdoor spaces in the City of London;

• Providing a resource library with information sheets and videos to help others learn about pollinators and take positive action;

• Creating an event series to engage members on the importance, needs, and joy of pollinators and their role in nature and human life.

TY: How do you become an entomologist?
KT: Someone interested in becoming an entomologist in the UK can take the academic route to study zoology, biology or other relevant degrees, and then do a Master’s or PhD in entomology. 

An alternative route can be to join an entomological society and attend courses on the group of insects that you’re interested in, and attend workshops and surveys to learn from more experienced entomologists. Regardless of which route one decides to take, the level of expertise will depend heavily on how much time is dedicated to studying them.

TY: Why are green roofs good for insects?
KT: In very built-up urban cities such as the City of London, there are limited green spaces at ground level, and many of them have restricted sunlight exposure, which is essential for most flowering plants and insects. Green roofs are often exposed to the sun for most of the day, and they can provide an excellent habitat for pollinators and other beneficial insects. They can also help establish biodiversity corridors and enable insect movement between green spaces.  

TY: How do you improve green roofs for insects/pollinators?
KT: Bees and other pollinators’ survival depends heavily on food and nesting resources. Many of them can have short flight ranges, between 150-600 metres (Gathmann & Tscharntke 2002); hence, nesting habitat and food resources must be in close proximity. Green roofs can be improved for insects / pollinators by providing diverse pollinator-friendly plants from March to October, and nesting resources such as bee / bug hotels for cavity nesters and mounds of sandy loam for ground nesters. 

www.tep.uk.com / Email: tomyoung@tep.uk.com

Contact Konstantinos +44 (0)75977 43175 / website: pollinatinglondontogether.com

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