Chapter 9 The long road to Freshwater Paths
John Measey
Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
It all started when I read another paper written by a group of German researchers published in Proceedings of the Royal Society of London (Vences et al., 2003). Their paper was exciting. They were using a phylogenetic approach to show that amphibians, without any doubt, had dispersed over marine barriers. I was fascinated. At the time I had just come back from one such island with an entire set of remarkable, endemic, amphibian species. I settled down to read the paper and was enthused to see what they would say about my study site and the amphibians it contained.
But the paper didn’t mention them. In fact, before the end of the first paragraph of the introduction, it even denied that their existence:
“One important argument for such interpretations, ever since Darwin (1859), has been that heretoforth no endemic amphibians were known from oceanic islands.”
— Vences et al. (2003)
The rest of the study was very nice. They went on to explain how they could show that a group of amphibians had crossed an oceanographic barrier. But for me, I was stuck on that first paragraph and that they had completely overlooked my study site when I thought that everyone knew about it. After all, if I knew about it, then surely this group of distinguished German researchers should know?
It was 2003, and I was a Marie-Curie Fellow at Institut de Recherche pour le Développement (IRD) stationed at Bondy near Paris. I had already been there 18 months following a couple of short post-docs in South Africa and Brazil. But my fellowship wasn’t going particularly well. I had visited the island of São Tomé on the recommendation of Bob Drewes (CalAcad), who I’d known for a number of years. Bob had spent nearly an entire conference banging on about São Tomé and how excellent it was, and how easy it was to find my study organisms: caecilian amphibians.
FIGURE 9.1: A combination of events started the ball rolling on this manuscript. The publication of Vences et al. (2003), indoctrination from Bob Drewes about São Tomé, and my visits there in search of the ‘cobra bobo’ (Schistometopum thomense).
I emailed Bob, sent him a copy of Vences et al. (2003) and asked how it was possible that they had forgotten about São Tomé, and what were we going to do about setting the record straight. Bob fired straight back that we should contact Vences and ask why they hadn’t included the (then) five known endemic species living on the island. Further, we asked whether Miguel would be interested in participating in a paper setting the record straight: that the endemic amphibians of São Tomé had undisputedly colonised the island by crossing a marine barrier, and that this had been (implicitly) known (although admittedly not explicitly stated) for more than 100 years (Bocage, 1873). São Tomé is one in a chain of volcanic islands (~13 Mya) in the Gulf of Guinea with minimum distances of at least 220 km from mainland Africa. The amphibians had been described since the mid-19th century, and their endemism had never been disputed. There followed some discussion and a delay while I went to Amsterdam to meet Miguel and sequence tissue that Bob had collected from an endemic frog (Ptychadena newtoni) from São Tomé.
From this point on, what had been intended as a simple reply to Vences et al. (2003) became something far more complex and interesting. I had met oceanographers at IRD who worked in the Gulf of Guinea, and discussed ideas relating to the colonisation events of these islands. Bernad Bourles’ data on oceanic currents and surface salinity was self-evident when put in this context. Lastly, Martim Melo was studying birds of the Cameroon line, and his expert knowledge about the island endemics was superlative - hence a comprehensive argument could be included about why the frogs had not been carried to the islands by birds.
9.1 Submitting the manuscript
The manuscript was finally finished and written up for Biology Letters as it proposed a new explanation about how it was possible for amphibians to cross saltwater barriers using freshwater paths. I was proud of the paper, and I was sure that it was appropriate for Biology Letters. It was submitted in September 2004, and it did get reviewed. One review was favourable, and the other pointed out four putative weaknesses, and suggested that for the paper to be more than conjecture some of these should be ‘strongly supported’ in order make the paper convincing.
I appealed. I wrote a long explanation as to how in fact the manuscript already tackled three out of the four points convincingly, and that the fourth could at least be given a high probability. I have no record of whether or not the appeal was even considered. Presumably not. So I was resigned to picking out another journal. Discussion ensued, and we decided on Journal of Biogeography. This required re-writing the manuscript as a full paper, but on reflection this also allowed me to pull in a lot more of my reading into the manuscript and more convincingly address the points raised by Reviewer #2 from our Biology Letters submission.
The new manuscript was submitted to Journal of Biogeography early in 2005, and once again it was reviewed. The reviews took a long time coming. I think I must have written and asked about it as the decision email started with an apology. This time the reviewers were not short and punchy, but very long, asking for a substantial rewrite, and more sequencing of the specimens to produce a more convincing phylogeny. My fellowship had ended and I was unemployed. Still working on manuscripts as well as funding applications, job applications and all those other occupations that make the life of an unemployed Early Career Researcher so much more painful and unfulfilling than those in work. Discussions about the reviews ensued, and it was decided that we needed to do the additional sequencing to produce the new phylogeny, and that this could be done by a new postgraduate of Miguel’s, Ylenia Chiari, while I got to work rewriting and responding to the text.
This was a real low point for me. I had a crisis in confidence as I was an inexperienced researcher trying to head up an important paper with much more senior scientists and fellow ECRs as co-authors. What did they think of how I was handling the manuscript? Had I imagined the importance of this work? Should I rather hand the manuscript over to someone with more experience? At the same time, the slow progress on this manuscript was impeding momentum on my career. I really wanted to be able to have this as a completed project. Lastly, I had that nagging doubt that someone, maybe even the reviewers, would publish on this subject before me. Many people had now seen this idea, and they all had access to similar resources that could provide similar lines of evidence. It was an uncomfortable time during which I came to believe that the manuscript would never be published.
That hiatus of doubt, sequencing and rewriting might have lasted as long as a year to 18 months. At long last, the sequencing and reanalysis was done and the manuscript rewritten with the extensive reviewer comments addressed.
the manuscript was again ready to submit and send back to Journal of Biogeography. More time passed. This time we managed to get a decision of Minor Revision, but the reviewers wanted us to change the title of the manuscript. They didn’t like “Freshwater Paths” and I felt heartbroken because this was at the crux of the manuscript, the idea that enough freshwater was exiting the Congo River in a very large plume that would lower sea-surface salinity all the way to the Gulf of Guinea islands. Under duress, I changed the title.
Happily for me, the Journal of Biogeography handling editor was Bob McDowell. Bob liked the title and urged me to change it back again. He also had quite a lot of suggestions to improve the readability of the text. Suddenly, I felt as if I was turning the corner on this manuscript. An editor liked it and was prepared to make sure that it was as good as it could be before going to print. It did shuttle forwards and backwards again a few times between myself and the Journal of Biogeography editorial team, but by then I had the feeling that it would all come out ok. Things were also looking up for me as I had a new postdoc starting. The paper was published in 2007: Measey et al. (2007).
FIGURE 9.2: Time spent on São Tomé also had its ups and downs. My field assistant Quintino Quade celebrates our fantastic haul of caeclians, after a day spent digging in the rain in the island’s forested interior.
9.2 Looking back
At the time, I would have been happy had the manuscript been accepted in Biology Letters, but it would not have been nearly as good as the manuscript that was accepted at the Journal of Biogeography. The reviewers that I was convinced were trying to make life as difficult as possible for the manuscript, had made it a lot better. I think that the editors of the Journal of Biogeography had made a huge difference in their commitment to getting a good manuscript for their journal.
The payoff has been that this has been one of my best cited papers over the years, and it’s a publication that I’m proud of. It introduced me to a better way of collaboration over antagonism when responding to an error made by colleagues, and it resulted in lots of connections with people from other disciplines that I would not have otherwise met.
The study has inspired others too. I’ve had a bunch of different undergraduates telling me that they read the paper as a part of their course, and enjoyed it (something that doesn’t happen too often). In addition, the study became the subject of a chapter in a popular book about biogeography by Alan de Queroz (2014): The Monkey’s Voyage: How Improbable Journeys Shaped the History of Life.