Hot weather impacts on invasive species

So, I’m guessing that you’ve all sat in your gardens in the blazing sun, BBQ lit, burgers lined up, drinking a beer …thinking to yourself …. ‘I wonder what impact this weather will have on my Japanese knotweed problem’ …

Well I’m sorry, it’s not good news.

You may be thinking – roast Knotweed being slowly baked in the sun, must be killing the stuff off…maybe I don’t need to take any action.

The reality, unfortunately, is that alien species don’t follow that rule.

Most invasive plants have better stress tolerance and can cope with high heat and drought much better than local species. Japanese knotweed thrives on the sides of volcanoes in its native Japan with active fumerols spewing sulphurous gases into the atmosphere adjacent to where they grow – temperatures are extreme and yet the plant continues to spread. A few days of increased temperature in the UK isn’t going to cause this plant any problems..

Faster reproduction – warmer temperatures speed up the life cycles for many invasive plants and animals allowing them to multiply more quickly than native species.

New territory – warmer climate allows non-native species to move onto cooler regions where it may previously have been too cold for them to survive. Many alien species are progressively moving northward as climate changes.

Weakened defences – many of our native plants respond to the stress caused by heat waves by having a weakened immune system making them susceptible to pests and diseases.

Extreme weather causes habitat damage creating large open spaces where new species can rapidly take over.

Reduced water levels in rivers ponds and reservoirs as well as dying trees mean loss of shade and hiding spots that animals rely on.

All of the above result in allowing invasive species to thrive by increasing their resilience and weakening native plants and animals.

Unfortunately, I’ve now ruined your barbecue and put you right off your beer.

Sorry.

Mike C