Prof. Helen Roy on Predicting Biological Invasions to Prevent Extinctions

On Tuesday 8 February 2022, CELCE and the Extinction Studies DTP co-hosted a fascinating seminar led by Professor Helen Roy (which you can watch here). Hailing from the UK Centre for Ecology & Hydrology (, Helen principally discussed the relationships between invasive species and extinction, particularly in island systems, but somehow found time to touch upon everything from ladybirds to citizen science. Helen wove a deft tapestry of links between biodiversity, extinctions, citizen science, and community participation in conservation exemplified the interconnectedness she addressed in her talk. Likewise, her attention to questions of scale, from the local to the global brought together epitomised the different levels and different kinds of extinction that we study. 

Many non-ecologists in the audience were struck by the revelation that only a few introduced non-native species become invasive, a phenomenon exemplified by the contrast between Britain’s tiny population of introduced Bryony Ladybirds near London and our exploding population of invasive Harlequin Ladybirds, which are implicated in the decline of native two-spot ladybirds. Helen also, by describing schemes to control invasive bumblebees in Chile and hornets in the UK, showed the important role citizen scientists, indigenous people, and local communities play in providing valuable and fascinating ecological information and combatting biological invasions – something the professional scientists in the audience found particularly thought-provoking! Islands featured heavily in Helen’s talk, as she took us on a jet-setting journey from the Caribbean, where invasive green iguanas threaten localised island species of iguana, to St. Helena, where she described the biosecurity measures needed to protect these vulnerable island ecosystems. Islands are particularly important, Helen explained at the Q&A afterwards, because they are likely to contain many highly localised and endemic specialist species, which can be outcompeted or displaced by more generalist invaders. And adverse impacts on one island specialist species can impact across an ecosystem largely composed of such unique specialists. 

The interconnections and interactions of the human and the nonhuman, and humankind’s role in ecology is an area particularly near to my heart, and Helen spoke eloquently about the need to address both ecosystems and societies, and engage people at the sharp end of biological invasions. She painted a wonderful picture of an interconnected world, where humans can play pivotal roles in both introducing invasive species and controlling them. It is easy to come out of discussions of extinction and the ongoing ecological crises feeling despair and anxiety, but Helen’s holistic view and boundless enthusiasm instead left me more convinced than ever of humanity’s ability to help our beautiful planet flourish. 

That’s not to say there aren’t any challenges. Helen’s talk demonstrated how huge knowledge gaps hinder any attempts to predict future invasions or identify species of concern. Similarly, Helen vividly outlined the shocking rate of ongoing biodiversity loss. Nevertheless, her emphasis on the interconnections between species, between ecosystems, between societies, normal people and nature, provided a wonderful perspective on how all of us can, as scientists, researchers and citizens, participate in the work which needs to be done in helping this planetary ecosystem we all share. 

Jon Roberts 

 Jonathan Roberts ( is a PhD student in the Extinction Studies DTP and the School of Biology at the University of Leeds.  He studies the history and biology of disease eradication, focusing particularly on hookworm and guinea worm, combining approaches from ecology, parasitology and the history of medicine.