The River Misbourne, England (April 2020)
Many established species we consider native due to our familiarity with them have in fact been introduced by humans, and have over time evaded our control. As a result invasive species can cause both ecological and economical harm. From a conservation standpoint, it becomes essential to control the spread of invasive species lest they decimate native species essential to the ecological integrity of an ecosystem. During the COVID-19 lockdown I’ve taken the opportunity to consider the invasive species that I see regularly, if not daily.
Since childhood, my favourite flower has been the English/common bluebell (Hyacinthoides non-scripta). There’s something quintessentially British about a woodland carpeted by a sea of purple. Spanish bluebells (Hyacinthoides hispanica), while beautiful, are not indigenous to Great Britain. Through rapid spreading and hybridisation between the two species, the threat against native bluebells continues to grow. Controlling the spread of these flowers in gardens (especially those bordering woodlands) is essential to the survival of our beloved native bluebells.
Another, perhaps more widely known invasive species is the North American grey squirrel (Sciurus carolinensis). They are such a staple in our daily lives and gardens that it is difficult to believe an entirely different species used to dominate this niche in most of the UK. Brought to Great Britain in the Victorian Era, these quirky mammals quickly outcompeted the smaller and beloved red squirrels (Sciurus vulgaris), our only native squirrel species. Their range in the UK has drastically reduced, primarily due to disease transmission and food competition with grey squirrels, and other stressors such as habitat loss. Scotland remains the last stronghold of the red squirrel and conservation efforts are ongoing to ensure the future of this incredible species.
Another invasive species I see occasionally where I live is the Muntjac deer (Muntiacus reevesi), introduced to Great Britain from China and Taiwan. These now common and very successful deer, while adorable, can seriously impact woodlands due to their grazing habits by preventing tree regeneration, therefore affecting native flora and fauna. While there are six species of deer found in Britain only two, roe deer and red deer, are truly native.
Worldwide, invasive species are thriving due to man-made decisions. Many of them, such as the lionfish, the zebra mussel and the Kudzu plant, have few or no natural predators in their new environment, allowing their populations to spiral out of control, severely impacting native species. It can be really interesting to look up the situation in your area and to see how you can help!