What is Eco-sourcing?
Eco-sourcing is “the propagation of native plants from a representative sample of the local wild population.” * This refers to the collecting of indigenous New Zealand plant propagating material (seeds or cuttings) from naturally occurring native stands of vegetation. The subsequent progeny are planted back in the same ecological district or locality from which they originated.
At a hui held at Wai-Ora this week, Dr Peter Heenan spoke on his recently published paper ‘Ecosourcing for resilience in a changing environment’ discussing the genomes of Mānuka and Kānuka throughout New Zealand. He argues that the strict boundaries of the current eco-regions of New Zealand should be re-examined and that the type of land that the parent plant is growing in is what is more important to the success of a planting. For example, a plant growing in a cold, wet situation will produce progeny that is suited to the same. Therefore, the region is less important than the situation of the parent plant and the planting. While this perspective is heavily debated, this article will use the traditional eco-sourcing boundaries to fully explain what eco-sourcing is.
Every community of native bush differs in species composition from neighbouring areas. The genetics of each species can also differ from others of the same species found in different areas. These genetic differences manifest themselves in many ways, the most obvious being visible differences in plant form or leaf shape, less obvious could be genetic immunity to disease. As a result, eco-sourced plants tend to be specified in ecological restoration and habitat rehabilitation projects.
At the recent hui, an excellent point was made that “Eco-sourcing is a process- a plant is only eco-sourced when it is planted.”(unknown). This statement clarifies what we mean by eco-sourcing. As a nursery, we eco-source all of our seed for revegetation projects. The goal of eco-sourcing is to enhance the ecological integrity and biodiversity of a particular area. Eco-sourcing aligns with the principles of ecological restoration by seeking to restore and enhance the natural balance and functions of ecosystems. While our plants are intended for restoration projects, some are shipped out of the region altogether and others are used in amenity plantings where their heritage is not important.
Why is eco-sourcing important in ecological restoration?
Rehabilitation of degraded or damaged ecosystems by human activities or natural events is the goal of environmental restoration. Restoration aims to return ecosystems to a more natural and healthy state, promoting biodiversity, ecological resilience, and sustainability.
Eco-sourcing plants from populations that are native to the specific geographic region or ecosystem where the project is taking place. These local populations have evolved to survive in the unique climate, soil, and other environmental factors of that area. Using plants adapted to local conditions increases the likelihood the plants will thrive within the first year after planting. Wai-Ora Nursery’s plants have had a 97% success rate in various planting projects throughout Canterbury in the last few years. These plants will go on to establish, grow, and reproduce, contributing to the restoration of native ecosystems.
Genetic diversity is crucial for the resilience of plant populations, enabling them to adapt to changing environmental conditions and resist diseases or pests. Using seeds from various local populations helps preserve the full range of genetic traits that have evolved. It helps prevent the introduction of non-native or genetically distant plant material that may disrupt local ecological interactions.
Restoring native plant communities through eco-sourcing contributes to the reestablishment of ecological networks. These networks facilitate the movement of species, helping to reconnect fragmented habitats and improve overall landscape connectivity. Eco-sourced plants are more likely to thrive, resist pests and diseases, and contribute to ecosystem functions.
Eco-sourcing is a critical strategy in ecological restoration. It enhances the ecological and genetic integrity of restored ecosystems, promotes biodiversity, and contributes to the long-term sustainability of restored landscapes.
Why does Wai-Ora grow Eco-sourced Native plants?
We aim to protect biodiversity by using appropriate plants for an ecological area and its environmental conditions. This preserves as much of our natural environment as we can and restores modified areas as close as possible to their natural state.
With this in mind, we’ve been growing eco-sourced plants for over twenty years. As part of our values, we take care and operate with integrity. This is reflected in our choice to supply ecological restoration projects with eco-sourced plants. By working to care for the land and our community, we believe that growing eco-sourced plants is our purpose. In 2019, we decided to focus solely on producing eco-sourced plants for Canterbury. This decision clarified how our actions reflect our values.
Local and Regional Identity
In Christchurch, which has few remaining natural stands of indigenous vegetation, eco-sourcing is of vital importance. Wai-Ora sources its seed from wild populations and advocates for eco-sourced plants to be used in landscaping as well as ecological restoration.
Eco-sourcing promotes a sense of local and regional identity. It utilizes plant materials that are part of the natural heritage of a specific area. Our focus on eco-sourcing Canterbury plants grown for Canterbury projects may seem provincial compared to the nationwide distribution efforts of similar nurseries. However, we already grow over fifty varieties of plants found in Canterbury, some of which can only be found in Canterbury. Canterbury is also heavily degraded, with most of the plains having ecosystem coverage of less than 5%, as seen in pink on the map above. (refer to Eco-index, a tool to aid in ecological restoration planning.) This demonstrates how important ecological restoration is for Canterbury.
Ecosystem Restoration and Preservation
Many organizations engage in ecosystem restoration projects to rehabilitate degraded habitats, combat invasive species, and enhance overall ecosystem health. Eco-sourced native plants are a key component of such restoration efforts. Growing eco-sourced native plants contributes to the preservation of indigenous flora, which may have cultural significance to local communities. This aligns with broader efforts to promote sustainable and culturally sensitive practices.
At Wai-Ora, we source from nearly 300 different properties in 20 different eco regions throughout Canterbury. We do not attempt to collect from every eco region but focus on what types of projects are coming up and their locations. When eco-sourcing, we source from the immediate vicinity of the planting project wherever possible. So, the seed collection plan needs to be finalised 18 months before a project is expected to take place.
After gaining permission from landowners, we collect from as many naturally existing parent sources in a locality as possible. Care is always taken to preserve existing natural stands. Seed collection starts in December with sedges and Matagouri. We prepare the Matagouri seed immediately for propagation. When grass-type seed comes back to the nursery, we clean and measure it, putting it into storage until later in the year. This is because those plants germinate and grow more quickly. Other species, particularly Coprosmas and Griselinea need to be sown fresh, so collecting the right number is crucial.
Shrubs and trees continue to produce seed until Autumn. This means that all summer, we collect seeds about twice a week throughout Canterbury, focusing on specific locations each time.
How does Wai-Ora track the eco-source of all the plants it grows?
When seeds are brought to the nursery, they are cleaned, weighed, and catalogued. The catalogue contains details for each source, including who collected the seed, the date, and GPS coordinates. Each entry is given a unique five-digit number beginning with the last two digits of the year of collection. For example, seed source 321 for the year 2023 is coded as 23321. The numbers grow consecutively from 001 and finish at the last lot of collection for the calendar year.
This seed number then becomes the stock code for that seed. Stock codes are designated with a C for cutting, S for seed and D for duff when material is gathered for propagation. Along with these signifiers, the eco location is recorded and follows each plant crop through production.
Each tray of germinating seedlings is marked with this information, which is then put onto a tag for each tray of plants and on the crop tag at the front of the crop. When a customer places an order, the best-suited eco-source is chosen for each species, if the source is available. Then, when picking up plants for orders, the dispatch team look for these specific codes for each order. In this way, we can trace each seed from the wild source through to the point of sale, and in many cases through to planting.
The challenges of growing eco-sourced plants
Wai-Ora endeavours to supply the best eco-sourced plant material available. However, we do not always have stock available from every region; in those instances, we offer the choice of alternatively sourced plant stock most suited to your climate and conditions. Supplying the right plant for a project comes down to growing it first and this is the biggest challenge.
Plants adapted to a particular climate may face difficulties when exposed to different climates. For example, frost-sensitive plants such as Ngaio and Māhoe need protection from frosts at Wai-Ora as the seedlings of these species are not adapted to our open growing environment. This tough environment is usually a strength in our plant production, as the plants grow hardy and are more likely to survive when planted out.
Human activities, such as urbanization, agriculture, and infrastructure development, can introduce disturbances to ecosystems. Wild sources of plants can be viewed as problematic for some landowners. They may choose to kill unwanted plants on their property. In other cases, roadside plants may disappear during road maintenance and construction. A plant population or a single plant may no longer exist when collectors attempt to collect seed.
Ethical Seed Harvesting
When collecting seeds or plant material from natural populations, nurseries should avoid harm to the local ecosystem and aim to preserve existing natural stands. This can be challenging. Harvesting should be done in a way that allows for the continued health and reproduction of the source populations. Harvesting seeds sustainably and ensuring genetic diversity in small populations is essential for successful plant propagation. At Wai-Ora, we only collect 20% of the existing seed on a specimen. We leave the rest for bird food and natural reproduction cycles. We cut seed heads off from sedges, flax and toetoe and remove only seeds from trees. Cutting tree limbs guarantees that there will be no source of seed from that limb the following year. It is a shortsighted practice.
Some plant species may be protected by conservation laws. Ensuring that the collection and cultivation of eco-sourced plants comply with legal and ethical standards is crucial. Seed legally belongs to the landowner and collecting seed on private or public property requires permission. Most landowners are happy to allow sustainable seed collection on their property, if permission is gained first, and the landowner knows when to expect the collector. Seeds on publicly owned land, like parks and roadsides, require an annually issued collection permit from the local council. The Department of Conservation has its own set of rules about seed collecting on DOC land which require permits. Fines are applicable.
Addressing these challenges requires careful planning. For most ecological restoration projects, Wai-Ora plans well ahead and has stock suitable for smaller projects in Canterbury. However, larger projects require seed collection of specific seeds up to five years before the project will be planted. This is because some species are incredibly slow growing and in other cases, it is because the seed is not available or viable in the one season collection before planting. We recommend that plant requirements be communicated with the nursery a minimum of 18 months before planting, 36 months being the ideal.
Seed Collection requires careful consideration and a commitment to sustainable practices. The goal is to minimize any negative impact on the local ecosystem while supporting the continued health and reproduction of the source populations. We choose specimens that are healthy and abundant, avoiding rare or vulnerable plants to minimize the impact on the population. The practice of collecting 20% of available seeds allows natural processes to continue, supporting the overall health of the ecosystem. We collect seeds to represent the genetic diversity of the population, like in our Forest Duff lines. This helps maintain the adaptability and resilience of the propagated plants, especially important in the face of changing environmental conditions.
Seed collection (as opposed to limb collection) allows the parent plant to continue its natural growth and reproduction cycle. Leaving tree limbs intact ensures that the structural components necessary for the tree’s overall health and seed production are preserved. This approach supports the continuation of annual seed growth. While collecting, we also note the health of source populations. If negative effects are observed, we may not collect any seed that year or note that the site needs some attention, especially if our ecological restoration team cares for the site.
*Taken from Commercial Horticulture’s article on eco-sourcing by Wayne Bennett. Feb/March 2010