Changing landscapes

Historically, humans have settled on land with productive soils and favourable climates located along waterways. Through urbanisation, new conditions have evolved. Our cities and neighbourhoods have undergone significant change in terms of temperature, climate and hydrology. This has created a myriad of micro-climates, sub-environments and novel ecosystems enabling cities to support a diversity of species, including threatened species20. In the midst of the biodiversity crisis, cities must act to enhance the biodiversity they support through implementing species specific and evidence-based solutions. We can no longer accept the notion that anything ‘green’ or any action will do.

Species have unique needs, requiring different food and habitat resources. The complexity of species within cities emphasises the need to understand species requirements, both within their natural range and novel urban ecosystems. Urban spaces have been vastly altered and species have responded to this change. For example, in the city of Perth, Carnaby’s black cockatoo relies on an introduced pine plantation, which enable the use of novel food resources in locations where their natural food source has been removed.

Emphasis on Indigenous

Many species are still largely reliant on the evolutionary relationships they hold with their Indigenous counterparts. In urban green spaces, indigenous plants are vital for supporting diverse insect communities and species they co-evolved with. However, vegetation structure also requires consideration. Research has uncovered that vegetative and structural complexity of a plant species, regardless of its origin, is as important in increasing biodiversity. Traditional urban management practices have favoured simplistic landscapes with minimal structure, for example grassed lawns with tree canopy, which hinder the potential for urban green spaces to support biodiversity and enable climate change action.

Species' resource requirments

Management interventions and restoration projects must carefully consider the resource requirements of species. For example butterflies rely on plants for food, and as hosts for the larval stage of their life cycles. Green spaces that are floristically diverse with a wide variety of larval host plants support greater diversity and abundance of butterflies25. However, resources relevant to one species may not be for another. Large woody trees are optimal habitats for cavity-nesting bees, while patches of bare ground are essential for supporting ground-nesting bees.

In a world where urban expansion is ongoing and our landscapes are constantly evolving with climate, it is crucial that biodiversity is planned for and present in our cities. Urban practitioners must understand the resource requirements of target species and ensure urban habitats offer a variety of resources to support diverse communities. Carefully curated urban habitats may act as places of refuge during periods of resource scarcity. These spaces will be integral to enhancing the capacity of cities and neighbourhoods to support biodiversity.