By Roisin Gowen
This research was conducted as part of an undergraduate project by Roisin Gowen at Trinity College Dublin, who assessed different park management strategies and how they impacted plant and pollinator diversity, and urban park users’ relationships with green spaces and biodiversity.
Roisin won the Environmental Sciences Association of Ireland Undergraduate of the Year Award 2021/22 for her research. This award recognises students in third level institutions who have excelled in the area of environmental research at undergraduate level.
How Can Urban Parks Help Pollinators?
Despite the overwhelming decline of pollinators and biodiversity in urban areas, urban green spaces are increasingly recognised as having pollinator conservation potential.
Amenities such as parks provide access to nature in urban environments where green spaces may be scarce. Consequently, there are calls to protect urban green spaces and their biodiversity, particularly plant and pollinator species.
Many urban green spaces are managed by local authorities under specific regimes. Parks are predominantly designed for public recreational use, and so are often subject to intensive management characterised by frequent mowing, lower plant height, and lower vegetation diversity.
But some areas are managed less intensively with less frequent mowing, higher plant height, and a greater number and diversity of flowers. Studies have shown how pollinators can thrive in appropriately managed urban green spaces with sufficient floral resources and nesting sites.
There is a balance to be struck: although urban green spaces must provide a service for people, they can also protect pollinators.
Surveying Parks in Dun Laoghaire-Rathdown
I carried out a study of several urban parks managed by Dun Laoghaire-Rathdown County Council.
This research focus was inspired by the second objective of the All-Ireland Pollinator Plan, which focuses on “making public land pollinator friendly”. My research sought to support this objective by determining which park management strategy is most effective in promoting plant and pollinator biodiversity in the selected urban parks in the Dun Laoghaire Rathdown County Council area.
The different types of management were represented by three commonly implemented strategies:
Amenity Grassland (AG): An area that is used for recreational purposes and is thus intensively managed and mowed, often referred to as the traditional management style of urban parks.
Formal Planting (FP): Planting in parks or green areas defined by a clear and organised structure of plants/vegetation. Like gardens, areas within these parks will range from being highly landscaped to lightly managed.
Areas Managed for Wildlife (AW): Areas and parks with low intensity management practices often designated by local or national authorities to promote biodiversity conservation whilst also maintaining its purposes for public use.
Replication was ensured by surveying three sites within each management style, resulting in a total of 9 parks surveyed (Fig. 1).
Areas Managed for Wildlife have far greater pollinator richness and abundance
Following quadrat surveying (for plant species) and observation transect walks (for pollinator species), I found that Areas Managed for Wildlife had a higher pollinator and plant richness and abundance compared to areas managed under Amenity Grassland and Formal Planting strategies (Figure 2).
This can likely be attributed to less frequent mowing, less intensive management, and less fragmented habitat structure. AW leads to greater floral diversity and abundance which, in turn, attracts more pollinators than more intensely managed areas.
Interestingly, there was a little difference observed between Formal Planting and Amenity Grassland strategies. Although FP presented a high variability in plant species richness and abundance, likely due to pockets of curated, diverse ornamental flower patches, areas managed under this strategy had overall low pollinator richness and abundance, similar to results seen in Amenity Grassland areas.
It was assumed that Formal planting would have had a more positive impact on plant diversity than Amenity Grassland. However, the disproportionately small area of these diverse flower patches compared to the remainder of the park area probably resulted in overall low levels of plant and pollinator diversity.
Improving our urban green spaces for pollinators and people
To improve pollinator biodiversity in urban parks, Areas Managed for Wildlife appears to be the best management strategy for several reasons.
From an ecological perspective, less intensive management supports a greater diversity of plant species. Areas Managed for Wildlife provided better habitats and resources for pollinator species, which in turn promoted greater levels of pollinator diversity. These areas were therefore the most beneficial and effective for improving plant and pollinator diversity, and could result in improved ecosystem services, ecosystem functioning and wider urban biodiversity.
Reducing management intensity not only reduces costs and saves time, but also promotes floral and pollinator diversity in urban parks relatively easily. Not only is this beneficial for our urban wildlife, but also for our urban dwellers. Increased exposure to natural habitats has been proven to have a suite of benefits for urban populations, including stress relief and better mental cognition.
Managing these important urban green spaces to provide these benefits will be increasingly important as cities face rapid urbanisation. Potentially, a more mixed management approach could be adopted, where more urban parks are subject to the AW management style.
Alongside the ecological survey, research was conducted which showed that increasing the proportion of Areas Managed for Wildlife in these parks would not disrupt their role as amenities for activities such as exercise, socialising, and relaxing.
Future studies and actions
The richness and abundance of pollinator species varies from year to year, so this research would have benefited from repeating over several years to see if patterns are consistent.
Additionally, most studies into urban bee diversity are on a local and landscape scale, so expanding this research across different countries could be valuable in determining broader trends of urbanisation and urban diversity. Comparing the impacts of management strategies not only in different parks, but also in the context of different cities and different countries could provide better insight into best practices for urban park management and biodiversity conservation on a much broader scale.
The results of this study suggest that more public urban green spaces in Dun Laoghaire-Rathdown County Council could be brought under the strategy of Areas Managed for Wildlife. Designing and managing parks for pollinators and plants would benefit not just biodiversity, but also the people who use these important green spaces.
About the author:
Roisin Gowen is an early-career environmental scientist with experience in research primarily focusing on urban pollinator conservation, nature-based solutions, renewable energy, and biodiversity conservation. She graduated from her BSc in Environmental Sciences at Trinity College Dublin in 2022, whereafter she has worked in a research role and project management.