Francesca Gherardi (1955–2013) – a woman of many talents

This special issue of Ethology Ecology & Evolution is dedicated to the memory of Francesca Gherardi, a good friend and a great woman, who passed away last year after a long struggle with cancer. Francesca was an outstanding scientist, who explored biological invasions in freshwater ecosystems, publishing articles and books in the most authoritative journals of the world, indeed significantly improving our understanding of the patterns of spread and impact of invasive species in these highly vulnerable ecosystems. Francesca collaborated with a large number of fellow scientists on a wide variety of topics and had nearly 300 publications to her credit. Francesca also dedicated much energy to teaching, creating a very productive group of young and enthusiastic researchers at the University of Florence, and also organising the only post-graduate course in invasion biology in Italian academia. It is for us a great pleasure to see that several papers of this volume are co-authored by ex-students of Francesca, confirming the high level of the science in the research group that she created.

Francesca was President of the International Association of Astacology (IAA) from 2004–2006. She was awarded Distinguished Astacologist status by the IAA in 2010 and was invited to give the Sture Abrahamsson Memorial Lecture at the IAA’s 19th international symposium held in Innsbruck (Austria) in 2012. She was an active member of the International Union for Conservation of Nature (IUCN) SSC Invasive Species Specialist Group for many years, providing advice to practitioners on the management of invasive species and inputs on policy making.

In Crayfish NEWS, volume 27, issue 2, (2005) (the newsletter of the IAA), one of us (David Holdich) wrote, “Why organize one conference in a week when you can organize two?” This relates to the fact that Francesca and her team not only organized the final CRAYNET meeting in Florence, but also an international workshop on biological invasions in inland waters (INWAT). Both were highly successful. This was typical of Francesca – always busy organizing meetings, finding the funds, giving papers in perfect English and making sure the outcomes were published. Francesca will be remembered by many for turning up at symposia with a group of her students trailing behind – she used to say, “I am a shepherdess and this is my flock”.

David first met Francesca on the side of a lake during a field visit during the 11th IAA symposium in 1996 at Thunder Bay (Canada). It was her first IAA symposium. We were being shown how the lake had been invaded by the rusty crayfish Orconectes rusticus. She said, “So you are David Holdich; how would you like to help me organize a workshop in Florence on invasive crayfish?”. Of course, Francesca was so charming that one rarely said “no” to her requests! She obtained the funds and set up the meeting without too much help from me! The meeting was the first of its kind to be held on invasive crayfish and was very successful – 70 delegates from 15 countries attended. It resulted in the publication in 1999 of “Crayfish in Europe as alien species. How to make the best of a bad situation?”, with Francesca and me as editors. Subsequently, I asked Francesca if she would contribute to my new book on crayfish, and she wrote an excellent chapter on crayfish behaviour in Biology of freshwater crayfish that was published in 2002. She then asked me to help her edit a book she was planning – Biological invaders in inland waters: profiles, distribution and threats – but I had to say no due to other commitments, although I did contribute a chapter with a colleague. Anyway, Francesca went ahead and did the editing on her own – the book amounted to 733 pages and was published in 2007.

Although when Francesca set out on the research trail in the mid-1980s she worked on freshwater crabs, and subsequently on hermit crabs and even the octopus, it was the invasion of Italian waters by the red swamp crayfish, Procambarus clarkii, that sparked her interest in crayfish in 1995. She continued this interest until her untimely death. Francesca gave her last presentation in January 2013. This was entitled “Integrating animal behavior and conservation biology: a case study of invasive crayfish”, and was given at the meeting of the Society of Integrative and Comparative Biology, in San Francisco. In what was her last individual publication, “Crayfish as global invaders: distribution, impact on ecosystem services and management options”, Freshwater Crayfish 19 (2): 177–187 (2013), she highlights the problems being caused by non-indigenous crayfish, both to indigenous crayfish species and the freshwater environment, and makes the prediction that “we should be ready to lose forever heritage crayfish species and suffer from the associated damage on ecosystems”. As shown by Holdich et al. in this volume, this is certainly proving to be the case in Great Britain, as it is in some other European countries, particularly France, Italy and Spain.

The compilation of articles of this issue well reflects the interests of Francesca in her studies, in particular on crayfish invasions, that she has investigated in all aspects, from the biological traits of invaders, to the large-scale patterns of invasions, to the impacts they cause.

In fact, several papers of this volume analyse the invasions by crayfish. The article by one of us (David Holdich) and co-authors provides an overview of invasions by crayfish in Great Britain, in particular focusing on the impacts caused by the American signal crayfish, costing over £ 2 million/year to GB. Huys and co-authors report interesting data on the introduction of several species of crayfish and of their symbionts in the area of Greater London. Souty-Grosset and several colleagues, including Francesca Gherardi, report the results of a study on the burrowing activity of the red swamp crayfish (Procambarus clarkii) in an area of France recently invaded by this species. In their article, Stephanie Peay and Alison Dunn discuss the efficacy of dewatering for controlling crayfish, providing interesting data for managers. On the issue of management, Paul Stebbing and co-authors provide a valuable review of the response to crayfish invasions, including prevention, eradication and management, and present suggestions to develop integrated approaches to this problem. The paper by Kozubíková-Balcarová and co-authors assesses the impact of the crayfish plague pathogen (Aphanomyces astaci) on indigenous crayfish in the Czech Republic, investigating in particular the possibility of the recovery of threatened species.

We are particularly glad to have had the possibility to publish the latest paper co-authored by Francesca and one of us (Piero Genovesi), finalized by two of her most brilliant former students, Giuseppe Mazza and Elena Tricarico, that focusses on the impacts of invasive species on human health, a topic on which Francesca had focused much of her work in her last year. The interest of Francesca in understanding the mechanisms of impact of invasive species is also reflected in the paper by Belinda Gallardo, based on a set of 10 of the worst invasive species in Europe, that analyses the main correlates of invasion, taking into account climatic, habitat and socio-economic factors, and highlighting the crucial importance of socio-economic factors in determining the vulnerability to invasions.

The biological traits of invasive species are the topic of the paper by Fanini and co-authors, who explored the daily activity patterns of the very harmful red palm weevil.

Several of the articles compiled here review regional or global aspects of biological invasions. The paper by Bella Galil and co-authors assesses the patterns of arrival of non-indigenous species in the European seas, based on a large dataset on marine organisms. The study highlights the rapidly growing rate of invasions in our seas, launches a question on the possibilities of achieving the targets set by the European Biodiversity Strategy, and suggests a more realistic target for 2020. Another review paper has been produced by Mattia Menchetti and Emiliano Mori, who have analysed the data of impacts by alien parrots at the global scale. The contribution by Verena Platt and Jonathan M. Jenscke investigates the very basis of invasions, testing two interesting hypotheses using data from 70 animal species, confirming that asexual reproduction is correlated to the invasion potential of animal species.

In conclusion, we believe the issue that you now have in your hands provides a valuable assemblage of studies of biological invasions in all their aspects, from the causes and general patterns of this phenomenon, to the mechanisms of impact, to the most effective response strategies that can be enforced. We believe that circulating these important contributions is the best way we have to honour the memory of our good friend Francesca, and we would like to thank the Chief Editor of the journal, Francesco Dessì-Fulgheri, for having invited us to be the guest editors of this volume.

More detailed tributes to Francesca can be found in the three articles below, including a list of her publications in Kawai et al.

1. Photo taken by David Holdich shows Francesca in organizing mode as she leads a party round Siena during a break from the 1997 Florence workshop.