With its picturesque landscapes and unique biodiversity, New Zealand is under siege. The invaders? Exotic plants. While they may appear innocuous, these non-native species pose a significant threat to the delicate balance of New Zealand's ecosystems. In this comprehensive exploration, Native Restorations delve into the problem of exotic plants, their origins, the importance of their removal, and how individuals and communities can combat this ecological menace.
Exotic plants, also known as non-native or invasive species, have been introduced to an environment where they did not evolve naturally. In New Zealand, these plants outcompete native flora, disrupt ecosystems, alter habitats, and threaten indigenous wildlife. Their rapid proliferation can lead to the degradation of natural areas, loss of biodiversity, and economic impacts on agriculture and forestry.
How Did Many Exotic Plants Get To New Zealand?
Introducing exotic plants to New Zealand can be traced back to human activity. Whether intentionally or inadvertently, settlers and travellers brought seeds, cuttings, and plant materials from their homelands. Some were introduced for ornamental purposes, others as agricultural crops, and some hitchhiked as contaminants in soil, cargo, or vehicles.
Today, New Zealand enforces strict biosecurity measures to prevent introducing exotic plants and seeds into the country. These measures are crucial for safeguarding New Zealand's unique biodiversity and agricultural industries from the potentially devastating impacts of invasive species.
Biosecurity Inspections: New Zealand's biosecurity system includes stringent inspections at ports of entry, including airports, seaports, and mail centres. Biosecurity officers thoroughly inspect incoming cargo, luggage, and mail to detect and intercept prohibited items, including plant material and seeds.
Risk Assessments: Before importation, plant material and seeds undergo risk assessments conducted by biosecurity experts. These assessments evaluate the potential risks the imported material poses, considering factors such as the origin of the material, its intended use, and the likelihood of introducing pests or diseases.
Import Restrictions: New Zealand maintains a list of prohibited and restricted plants and seeds that cannot be imported into the country without special permits or exemptions. Prohibited items are strictly banned from entry, while restricted items may be permitted under specific conditions, such as treatment or certification requirements.
Permits and Certifications: Before importing plant material and seeds into the country, importers must obtain permits or certifications from New Zealand's biosecurity authorities. Permits may require pre-export inspections, treatments, or documentation to ensure compliance with biosecurity regulations. In sunny Marlborough, New Zealand we take biosecurity very seriously when it comes to the care of our environment. The Marlborough District Council is passionate about the eradication of pest plants and species, leading the way to protect natural habitats and native flora and fauna.
Quarantine Facilities: Incoming plant material and seeds may be subject to quarantine procedures to prevent the introduction of pests or diseases. Quarantine facilities provide controlled environments where imported items can be inspected, treated, or tested before release into the country.
Public Awareness and Education: New Zealand's biosecurity agencies, such as the Ministry for Primary Industries (MPI), engage in public awareness campaigns and educational initiatives to inform travellers, importers, and the general public about the importance of biosecurity and the risks associated with bringing prohibited items into the country.
International Collaboration: New Zealand collaborates with international partners, including other countries, international organisations, and research institutions, to share information, best practices, and scientific expertise related to biosecurity and invasive species management.
By implementing these comprehensive biosecurity measures, New Zealand aims to prevent introducing exotic plants and seeds that could threaten the country's ecosystems, agriculture, and natural heritage. These efforts are essential for protecting New Zealand's unique biodiversity and maintaining the health and integrity of its ecosystems.
How to Remove and Report Exotic Plants in New Zealand
Recognising and removing exotic plants is crucial to preserving New Zealand's native ecosystems. Individuals can contribute by familiarising themselves with common invasive species and reporting sightings to local authorities or environmental organisations. Removal methods vary depending on the species and the scale of the infestation but may include manual pulling, herbicide application, or biological control measures.
Main Exotic Weeds and Plants in New Zealand
Several notorious exotic weeds and plants have established themselves in New Zealand, wreaking havoc on native ecosystems. Some of the most prevalent include:
Gorse (Ulex europaeus) - This spiny shrub crowds out native vegetation and is particularly problematic in pasturelands.
Old Man's Beard (Clematis vitalba) - A rampant climber that smothers trees and shrubs, disrupting forest ecosystems.
Japanese Knotweed (Fallopia japonica) - Known for its rapid spread and destructive root system, Japanese Knotweed can cause structural damage to buildings and infrastructure.
Wild Ginger (Hedychium gardnerianum) - This invasive plant forms dense colonies, displacing native understory species in forests. The World Conservation Union considers it one of the 100 worst invasive species in The World.
Tussock Needle Grass - This resilient perennial tussock grass, often referred to as Chilean Needle Grass, has established itself as an invasive species within New Zealand's ecosystem. See below for an example of invasive Tussock and native Tussock. Making this a challenging pest to eradicate to the untrained eye.
What Plants Are Banned in New Zealand?
New Zealand has implemented strict biosecurity measures to prevent further introductions of invasive species.
Purchasing, selling, and propagating certain plants is prohibited under the National Pest Plant Accord (NPPA). The NPPA serves as a regulatory framework to prevent the sale, distribution, and propagation of specific pest plants across New Zealand, as outlined in the Accord list. These designated plants are classified as unwanted organisms under the Biosecurity Act 1993, making their distribution or sale illegal in New Zealand. The NPPA focuses primarily on pest plants that are widely spread through casual and formal horticultural trade.
While it's not mandatory to remove an NPPA-listed plant from your garden if it's already present, propagating or relocating such plants from your property is unlawful.
Many plants are banned from importation or cultivation, with a few examples listed below. For an in-depth search of the entire list of prohibited plants, the Ministry for Primary Industries (MPI) has a wonderful search option here.
Water Hyacinth (Eichhornia crassipes) is a highly invasive aquatic plant that can rapidly cover water bodies, impeding navigation and disrupting aquatic ecosystems. Although these plants may seem beautiful, they are serious water weeds.
Alligator Weed (Alternanthera philoxeroides) - Another aquatic menace that forms dense mats, choking waterways and displacing native aquatic plants and wildlife.
Salvinia (Salvinia molesta) is a free-floating fern that can clog water bodies and negatively impact biodiversity. It poses a serious threat to New Zealand’s precious water ecosystems.
Banana Passionfruit—The banana passionfruit, originating from the Andes, is a highly invasive tropical vine known for its aggressive growth in disturbed areas. Its detrimental effects include the suppression of trees, a decline in biodiversity, and the promotion of invasive species like feral pigs, which are attracted to the fruit as a food source.
Port Jackson Fig Tree - The Port Jackson fig, a type of strangler fig, is characterised by its ability to grow into a long-lived, sizable tree. This species poses a threat as it can harm or even kill the host plant it wraps around. It exhibits invasiveness by encroaching upon scrub and forest areas in various stages of succession, regardless of disturbance. Notably drought-tolerant, it poses a significant danger to native lava communities, such as those found on Rangitoto Island.
Rhododendron Ponticum - While the wild rhododendron poses a significant pest problem in Britain, its naturalisation in New Zealand remains limited. This species forms dense patches as its branches take root, creating an impenetrable mass. The thick canopy of leaves blocks sunlight, depriving native plants of vital light and hindering the establishment of new growth underneath. Additionally, the species spreads through both rooting branches and the dispersal of tiny seeds by the wind.
If you've encountered or suspect the presence of exotic pests or diseases, please contact the Biosecurity New Zealand Exotic Pest and Disease Hotline at 0800 80 99 66 or report online at report.mpi.govt.nz/pest. Your prompt reporting is crucial for safeguarding New Zealand's ecosystems and agricultural industries.
What Plants Should I Choose to Help Protect Native Flora and Fauna In New Zealand?
Choosing native plants for landscaping and revegetation projects is an effective way to support indigenous biodiversity. Native species are adapted to local conditions and provide essential habitat and food sources for native wildlife. Some recommended native plants include:
Pōhutukawa (Metrosideros excelsa) - Known as the New Zealand Christmas tree, this iconic coastal tree provides nectar for birds and insects.
Kōwhai (Sophora spp.) - With its vibrant yellow flowers, kōwhai attracts native birds such as tui and bellbirds.
Harakeke (Phormium tenax) - A versatile plant used by Māori for weaving, harakeke supports a variety of native insects and birds.
Kaka Beak (Clianthus puniceus) - This striking shrub produces clusters of vibrant red or orange flowers, attracting native birds like tui and kaka.
Pūriri (Vitex lucens) - A majestic tree with glossy leaves and clusters of purple flowers, pūriri provides habitat and food for native birds and insects.
Nikau Palm (Rhopalostylis sapida) - The only native palm in New Zealand, the nikau palm adds a tropical touch to gardens and provides shelter for native birds.
Kahikatea (Dacrycarpus dacrydioides) is New Zealand's tallest native tree. It is well-suited for wet areas and attracts a variety of bird species.
Cabbage Tree (Cordyline australis) - Its distinctive tuft of leaves and creamy-white flowers makes it a hardy and versatile plant for gardens and landscaping.
Hebe (Hebe spp.) - With a wide range of species and cultivars available, hebes offer diversity in size, foliage, and flower colour, making them popular choices for gardens.
Pittosporum (Pittosporum spp.) - This diverse genus includes many species native to New Zealand, offering options for hedging, screening, and ornamental planting.
Toetoe (Austroderia spp.) - Also known as New Zealand tussock, toetoe adds texture and movement to gardens with its tall, graceful seed heads.
Coprosma (Coprosma spp.) - With glossy foliage and colourful berries, coprosmas are excellent for adding interest to gardens and attracting native birds.
Koromiko (Hebe stricta) - A hardy shrub with slender leaves and spikes of purple flowers, koromiko is ideal for sunny, well-drained spots in the garden.
With a bit of consideration for the precious New Zealand ecosystem, avid gardeners can create beautiful landscapes while supporting local biodiversity and providing essential habitats for native wildlife by incorporating these native plants into their gardens. At Native Restorations, we are passionate about encouraging avid New Zealand gardeners to embrace our native flora. This not only has a wonderful impact on the aesthetic of your yard, but it will also attract native species and wildlife into your local area.
Community Involvement in Exotic Plant Management
Individuals alone cannot win the battle against exotic plants. Community involvement is essential for effective management and eradication efforts. Community groups, conservation organisations, and local councils often organise volunteer events, weed control initiatives, and educational campaigns to raise awareness and mobilise action. By working together, communities can protect New Zealand's precious natural heritage for future generations.
Sadly, the threat of exotic plants in New Zealand is real and pressing. Through vigilant monitoring, proactive management, and collective action, we can mitigate the impacts of invasive species and safeguard the integrity of New Zealand's ecosystems.
It's time for us all to join forces in the fight against botanical invaders and ensure a thriving future for all who enjoy life under the long white cloud.
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