Plant Health and Biosecurity

Globally, the impact of invasive alien species is second only to habitat destruction in terms of the most important cause of biodiversity loss.

Invasive alien species are organisms (animals, plants, microorganisms) that are introduced accidentally or deliberately into a natural environment where they are not normally found, with serious negative consequences for their new environment.  They represent a major threat to native ecosystems, and their impacts are exacerbated by human activity, trade, habitat disturbance, pollution and climate change, amongst others. Globally, the impact of invasive alien species is second only to habitat destruction in terms of the most important cause of biodiversity loss.

Plant Health and Biosecurity
Asian longhorn beetle which poses a serious threat to a wide range of broad-leaf trees outside of its natural range.

Over the centuries, botanic gardens have introduced many thousands of plant species from around the world into cultivation. The majority of plant introductions to botanic gardens have been beneficial but inadvertently some have had characteristics which make them invasive in the region they are introduced. It is estimated that in Europe, 80% of current invasive alien plants were introduced as ornamental or agricultural plants. Invasive plants, which were introduced deliberately as ornamentals, include Japanese Knotweed (Fallopia japonica), common rhododendron (Rhododendron ponticum) and giant hogweeds (Heracleum spp.).

Botanic gardens need to be aware of their responsibilities to prevent future invasions. Several codes of conduct have been developed by and for botanic gardens, for example the Invasive Plant Species Voluntary Code of Conduct for Botanic Gardens and Arboreta and the European Code of Conduct for Botanic Gardens on Invasive Alien Species.

Due to the way in which many plant collections are organised and because of the increased movement of plants and plant material, as well as mobility of staff and visitors, botanic gardens and arboreta can be especially vulnerable to the impact of invasive plant pests and pathogens. Such organisms can arrive in botanic gardens naturally, for instance through range extension, but introduction through human activity, whether deliberate or accidental, is the most common pathway.

Whether botanic gardens are receiving or sharing plant material, it is vital to ensure that neither the plant itself nor any associated pests or diseases will affect the collections of the botanic garden or the wider environment. Careful planning, preparation and management of plant material, good record keeping and robust procedures can help safeguard biodiversity and avoid serious environmental and economic impact.

Additionally, botanic gardens provide a unique tool in combating invasive alien species. Botanic gardens are estimated to contain 30% of all known plant species, many of which are exotic species. These specimens can therefore act as plant sentinels that help to predict which organisms are likely to pose a threat in the sentinel’s native range in the future. BGCI’s International Plant Sentinel Network aims for institutes to work together in order to provide an early warning system of new and emerging pest and pathogen risks.