One form of acroecology (“ecology of agricultural systems with respect to soil science, plant science, insect ecology and their interactions”[1]) is called permaculture. This example of NBS is a sustainable land use system that applies natural processes found in healthy ecosystems to human-made environments in order to create stable, sustainable systems.[2] Ecosystem components, including biotic and abiotic factors, are considered as a web of relationships. “In a natural ecosystem, there is no waste; instead, the outputs of one element become the inputs of another.”[3]
With this in mind, permaculture aims to design “self-sustaining, holistic and stable systems.”[4] As an example, rather than applying commercial fertilizers, permaculture systems may rely on manure, compost, mulching and the use of nitrogen-fixing plants to enrich soil. While conventional practices may include separating food gardens from flower beds and naturalized areas, permaculture blends different purposes into a single ecosystem. Many practices used in permaculture are derived from Indigenous practices of acroecology.[5]
Recommended Practices
There are twelve principles to permaculture:[6]
Observe and interact. Employ adaptive management in the system.
Catch and store energy. Aim to keep energy in the system for as long as possible. This includes various forms: living biomass, solar energy, wind, water and waste
Obtain a yield. The yield must be sufficient to provide food, as well as energy, social benefits and ecosystem services. In this way, permaculture focuses on a holistic understanding of yield and takes into account the efficiency of the system versus effort inputs.
Apply self-regulation and accept feedback. The system should be as self-sustaining and self-regulating as possible. Maximizing the ecosystem services within the system is key to permaculture being self-regulating. Permaculture uses both positive and negative feedback loops: positive feedback promotes energy accumulation and speeds up growth, while negative feedback increases the resilience of the system in the case of instability or scarcity.
Use and value renewable resources and services. Permaculture focuses on maximizing the use and function of ecosystem services. Waste (e.g., manure) can be used to revitalize soils and nutrient cycles and to mitigate drought. Nitrogen-fixing legumes can be used to provide more efficient yields of plants by adding this nutrient to the system.
Produce no waste. These systems operate as a cycle of energy and matter, so anything considered waste in a conventional system should be utilized for a purpose in permaculture and considered an integral part of the system.
Design from patterns to details. Permaculture aims to mimic natural ecosystems as much as possible. As such, natural ecosystems should be observed and their patterns replicated, while considering abiotic factors.
Integrate rather than segregate. Rather than having separate garden and flower beds, for example, permaculture integrates all parts of the “farm” system, including combining livestock and crops into one area. In one example, chickens can be loose in a fruit orchard and used as pest control for the plants.
Use small and slow solutions. Permaculture may be slower (i.e., availability of nutrients from nitrogen-fixing legumes versus from commercial nitrogen fertilizer); however, the systems are designed to be more sustainable in the long-term and more efficient uses of land.
Use and value diversity. Increasing biodiversity through permaculture can lead to more stable provision of ecosystem services and increased resilience and self-sufficiency of the food production system as a whole.
Use edges and value the marginal. Increasing the heterogeneity of the landscape and land uses creates more edges that add value through the provision of ecosystem services such as pollination and supporting natural predators to pests. Edges and “marginal” land may be more diverse and productive in a permaculture system.
Creatively use and respond to change. Since permaculture aims to emulate ecosystems, it can provide dynamic stability and flexibility for the system to adapt to changing conditions and evolve over time.
Project Considerations
Municipalities, developers and communities or individual homeowners may leverage permaculture systems to reduce urban air pollution through the plants used. Permaculture experts and agroecologists should be consulted in the planning stages of the implementation of this type of NBS.
The Business Side
Permaculture does not require specialized equipment, capital-intensive solutions or continual inputs (e.g., fertilizers) and can therefore be a cost-effective solution to producing food and mitigating air pollution in urban areas, particularly in marginalized communities.[7] When used in cities, whether on public or private property, permaculture can increase local food security and the provision of valuable ecosystem services in the community. It can be practiced in an urban backyard, or scaled up by communities to much larger systems.
The Nature Side
Food production systems designed from a permaculture perspective aim to maximize their similarity to nature and ecosystems, thereby providing an increase in biodiversity and ecosystem services, such as nutrient cycling, soil building, carbon sequestration, water infiltration into soil and uptake by plants (which can have a positive impact on erosion and flooding during major weather events) and reduction in the urban heat island effect. Since permaculture does not employ chemical fertilizers or pesticides, it can provide benefits to pollinators and water quality as well.
The Community Side
The permaculture principle to integrate rather than separate also applies to community and this example of NBS aims to bring people together through collaboration, sharing, trade and gathering places. Permaculture also can add nature to urban and periurban areas, which has positive impacts on human physical and mental health. Food produced in these systems adds to local food security and production. Since the systems are designed to mimic natural ecosystems, they can also bring enjoyment to people through recreational activities related to wildlife viewing.
[1], [5], [6] Krebs, J. & Bach, S. 2018. Permaculture—Scientific Evidence of Principles for the Agroecological Design of Farming Systems. Sustainability 10(9):3218.
[2], [3], [4] Grewal, A. 2014. Green Acreages Guide: Landscape and Garden Chapter. Land Stewardship Centre of Canada.
[7] Moran, C. 2019. Using Plants in Conjunction with Permaculture Design Principles to Provide an Effective and Affordable Way to Address Air Pollution in Urban Areas. SECAM 2019 – Yaoundé – Cameroon.
Grewal, A. 2014. Green Acreages Guide: Garden and Landscape. Land Stewardship Centre of Canada.
Krebs, J. & Bach, S. 2018. Permaculture—Scientific Evidence of Principles for the Agroecological Design of Farming Systems. Sustainability 10(9):3218.
Moran, C. 2019. Using Plants in Conjunction with Permaculture Design Principles to Provide an Effective and Affordable Way to Address Air Pollution in Urban Areas. SECAM 2019 – Yaoundé – Cameroon.