Blog #2 in our ‘Ask The Expert’ series: Climate change and inns adaptation
Insights from Eloise M.K. Holmes Msc, Bsc
Both the climate crisis and invasive non-native species (INNS) cause severe threats to biodiversity and human health. In our previous blog we explored how the combination of the two is impacting ecosystems, and how all stages of invasion will be impacted by climate change. This poses a significant challenge to species management companies, who have had to evolve their methods to match the adaptation of INNS in our changing climate. Let’s look at the current management techniques and how feasibly they can be changed, before diving into how species adapt to change.
General(ised) principles
The UK government currently restricts importing, keeping, breeding, transporting, selling or cultivating INNS. However, private collectors and licensed keepers (i.e., for research, conservation or education) may keep potentially dangerous species. If you find an INNS on your land, there is a lot of information surrounding INNS by the government but isn’t always where you expect to find it. However, you should take this advice with a pinch of salt as it is highly simplified and may not apply to your exact INNS scenario. Before removing an INNS from your land, consider conducting an Environmental Impact Assessment (EIA) or site survey to determine the biodiversity levels in the affected area and whether any protected species reside there. This will be important baseline information for monitoring the area after INNS removal.
The issue with invasive plants in England and Wales is the severity of establishment, and the multiple sources of entry. The most recent comprehensive review of UK INNS policy was conducted over 5 years ago, called the Great Britain Invasive Non-native Species Strategy (2015). This was first published in 2008 following a comprehensive review of policy in 2003. However, the economic impact, effectiveness of campaigns and frameworks for eradication are yet to be updated.
I’ve found an alien!
If you live in the UK and are impacted by an INNS, government might allocate you a “Country Stewardship” grant. You get £340 per hectare to control the species using appropriate methods, but it only applies to specific species like Himalayan balsam, Japanese knotweed and the aquatic Floating pennywort. These grants also come with a catch – there is a comprehensive but somewhat confusing matrix of advice and guidelines to follow (SP4: Control of invasive plant species supplement – GOV.UK (www.gov.uk). We’ve whittled this down into four main approaches to controlling the spread of invasive plant species: physical removal; chemical control; burning; direct consumption.
Roots up
Physical removal of an INNS includes cutting back the plant to prevent seed dispersal, digging and pulling it out whole. Disposing of potentially toxic plants yourself can be dangerous, so enlisting the help of a professional is crucial. Removed plants (or plant waste material) need to be disposed of alongside the soil surrounding their roots, in a place where risk of re-establishment is minimal. Burial in landsites or specialist locations can be carried out by a company, such as Environment Controls (EC) that holds a Waste Carrier’s Licence as there are regulations to be followed in the RPS 178 document (Treatment and disposal of invasive non-native plants: RPS 178 – GOV.UK (www.gov.uk). The waste can be sent to authorised landfill sites or specialist disposal sites listed by local councils or on the Environment Agency’s (EA) public register. Do NOT compost removed INNS as they are likely to survive and re-infect whatever soil they are put into.
Chemical control
INNS can also be controlled using government approved herbicides. Repeat treatments are often required to prevent regrowth, especially in larger patches. Permission from Natural England is required to chemically control INNS in protected areas, alongside agreement from the EA if in/near water. This is because herbicides entering the watershed can cause mass elimination of aquatic life through a process called eutrophication. However, it must be noted that only certain Glyphosate products are approved for aquatic use, main issues are run-off of other herbicide formulations hence why we have LERAP’s (local environmental risk assessment for pesticides). This gives a buffer zone between the waterbody and the product being sprayed. It’s also important to carry out a COSHH assessment, and hold a certificate of competence for herbicide use or be supervised by someone who does. Chemical control must be carried out with regard to the ecosystem to avoid herbicides used on an INNS affecting surrounding native species.
Burn it with fire (not recommended)
Not to be used for INNS listed on Schedule 9 of the Weed Act, especially Hemlock as burning would release toxins. This method requires a ‘burning waste in the open’ exemption from the government, and regulations are surprisingly vague. According to the RPS 178 document, you must not “cause a nuisance” and should follow local bylaws on burning. You must also not “cause risk to water, air, soil, plants or animals”, or “harm countryside or places of special interest”. It’s a good idea to contact your local council to check if burning is permitted, as this method may not guarantee complete destruction of the plant rhizomes/ roots and risks collateral damage to surrounding plant life.
Aliens for tea
You can find a plethora of online blogs and advice services on consumption of INNS, many of which include recipes, however, as with any foraging activity, it’s important to take caution when harvesting invasive species for consumption, as they can be mistaken for toxic imitation species. For instance, Japanese knotweed (Reynoutria japonica) can be used in similar ways to Rhubarb but other species such as Hemlock Water Dropwort is highly poisonous. Direct consumption of invasive species is certainly a controversial management technique. Creating a market may prompt pressure to maintain a problematic species, leading to recreation in uninvaded regions. Could this trigger local protection of harmful species and exacerbate the management problems we currently face? Many questions remain to be answered in this arena of INNS management – if indeed it can be called ‘management’!
Species adaptation
Plant adaptations are specific changes to a plant (species) that help it increase its chances of survival in a given environment. When their specific habitat changes, and this could be due to a climatic or ecosystem switch, biological changes must also happen for it to thrive. This can be in the form of physiological, structural or behavioral adaptations. Adaptation is not instant, it happens gradually over a period of time and as a result of a change in gene expression or random mutations. As the changes get passed on to future generations of the species, it becomes adopted by the species – natural evolution. Those that do not adapt will naturally die out.
Control adaptation
As INNS adapt to climate change so must weed management companies also adapt their skills and methodology to match, otherwise we may lose the battle for control. The buzzword within the industry is Integrated Weed Management (IWM). This approach looks at ways to diversify the methods used, or use multiple methods to achieve the best results, without harming the environment or its natural habitats. Switching up the traditional ‘ingredients’ of a treatment programme may mean a combination of several carefully chosen methods and conservation techniques.
It will pay to keep a degree of fluidity with IWM as the planet continues to heat up, get wetter, drier or simply more difficult to culture and sustain. Choice of chemical, its usage or volume used may also need to change, as they become either less or more effective. Mechanical techniques may become more effective, and the use of equipment such as drones may make works easier as rivers either flood or dry up seasonally.
And finally…
When working towards INNS removal from a region of land, each stage of establishment should be considered and addressed. These include:
- Transport and introduction
- Establishment of new invasives
- Altered impact of existing invasives
- Altered distribution of existing invasives
- Altered effectiveness of control strategies
Here’s the Government’s list of widely spread INNS in England and Wales:
Invasive non-native (alien) plant species: rules in England and Wales – GOV.UK (www.gov.uk)