Blog #1 in our ‘Ask The Expert’ series: Climate change and inns adaptation
Guest blog by Eloise M.K. Holmes BSC, Msc
We asked marine biologist Eloise for her views on climate change and INNS adaptation.
Around 1/5th of our planet is at risk from plant and animal invasions. Invasive, non-native species (INNS) are currently classified as any non-native animal or plant introduced outside its natural past or present distribution. INNS establishment can cause severe damage to the environment, the economy, our health and the way we live. Meanwhile, it is widely understood that the persistent increase in global average temperature is a symptom of climate change, directly linked to rising atmospheric CO2 concentration. Extreme weather patterns are predicted by climate changes around the globe, now unignorably impacting the UK. Events such as heatwaves and floods have littered the news during the summer of 2022 and are worse in 2023, with temperatures surpassing 40∘C for the first time in history (see The Future of Extreme Weather Events and Climate Change in the UK | Earth.Org for more).
So what does climate change mean for INNS, and how will this impact our lives in the decades to come? This question increasingly beleaguers the scientific community, and for good reason. Predicted outcomes for humanity under future climate scenarios depend highly on the outcomes for native plant species, and the degree to which they are impacted by the double whammy of climatic changes and encroachment by INNS. What’s so special about native species? Whether you realise it or not, you consume (directly or indirectly) plant-based products every day. Be it the oxygen you breathe, the cereals grown for your toast, or the fibres used to make your clothes, plants matter to you.
What is a ‘native’ and why should we care?
Native plants are indigenous to a certain region as a result of natural evolution. They typically occupy branches of a complex ecological hierarchy underpinned by facilitative relationships. This means success of one species depends on the proliferation of another, both of which are dependent on the level of grazing they receive. When one branch of the hierarchy is disturbed, its relationship with dependent and supporting branches is broken down. Such consequences are common with the out competition of native species by an INNS. Persistence of extreme environmental conditions, combined with the ability of many INNS to survive these new extremes, may increase the extent to which we lose our native species and the facilitative roles they play in ecological hierarchies.
Ecological interactions
We can expect range shifts in both native AND invasive plants, decreased ecosystem functional diversity and varied responses of insect pests and other organisms depending on plants affected by climate change. The complex ecological hierarchy we discussed stands subject to great changes, now and in the future. And whilst climate change impacts every ecosystem on the planet, its effects are unequally felt across the tree of life. The responsiveness of a species to climate change is highly dependent on its capacity to evolve and retain adaptive traits to enhance survival in the new conditions, or to expand to more suitable environments.
Plants, being highly sessile (non-moving), are limited to their innate genetic diversity and dispersal mechanisms. For instance, the dandelion propagates by its seeds blowing across the landscape and settling in a new location. Other plants use different dispersal mechanisms, like pollinating insects and birds which consume and/or carry propagules to new locations. These facilitative relationships are particularly vulnerable to both invasion and climate change, as the environmental tolerance of consumer species may not necessarily match that of the plants making up their diet. Many invasive species are mimics of the native they out compete but are toxic when consumed. One such example is the highly poisonous Hemlock water dropwort, often mistaken for the edible herb Chervil which is popular with foragers.
Future invasions
So far, we’ve discussed the impacts of climate change on existing invasive species. But what about new ones? The establishment of an INNS can be broken down into several phases. In 2008, Hellmann et al. predicted that climate change would alter every one of these stages in some way or another. This means 1) altered transport and introduction mechanisms, 2) establishment of new invasive species, 3) altered impact of existing invasive species, 4) altered distribution of existing invasive species, 5) altered effectiveness of control strategies. Food security is a growing concern for scientists across the globe, and the UK is no stranger to this.
A scapegoat for food security is genetically modified organisms (GMO), with certain traits such as rapid growth, broad environmental tolerances and far-reaching dispersal mechanisms being selected for. Unfortunately, these traits are synonymous with the characteristics of species able to colonise new environments and become invasive. Indeed, peaceful coexistence of GMO with non-GMO plants is a myth.
Read more about this topic in the next blog in this ‘Ask The Expert’ series: