2019 Julie S Denslow & Peter Ashton Prizes for the Outstanding Articles Published in Biotropica

Abstract

Every year, Biotropica’s Editorial Board selects two outstanding papers published in our journal in the previous calendar year as the recipients of the Julie S. Denslow and Peter Ashton Prizes, with which we honor the outstanding articles published in our journal in the previous calendar year. Criteria for selecting the papers to receive these awards include clarity of presentation, a strong basis in natural history, well-planned experimental or sampling design, and the novel insights gained into critical processes that influence the structure, functioning, or conservation of tropical systems. Below the authors of the award-winning articles describe what motivated their studies and how they hope the work will inspire other researchers; we hope you enjoy these insights into the process that led to their discoveries and ask that you join the Editorial Board of Biotropica and The Association for Tropical Biology and Conservation in congratulating the 2019 recipients.

Jennifer S. Powers, Editor-in-Chief

University of Minnesota

St. Paul, USA

Orou G. Gaoue, Choukouratou Gado, Armand K. Natta, and M'Mouyohoun Kouagou. 2018. Recurrent fruit harvesting reduces seedling density but increases the frequency of clonal reproduction in a tropical tree. Biotropica 50: 69–73.

Sub-saharan Africa produces less than 1% of the world scientific publications (Sooryamoorthy 2018), and addressing this issue is an important academic and development imperative. Strategic capacity building in science can play an important role in improving Africa’s contribution to global scientific research. I was born and raised in Africa but received my PhD in the United States. Holding an academic position in the United States and actively collaborating with scientists in Africa gave me a different perspective on the importance of and the kind of scientific capacity building that is needed in Africa. The low scientific productivity in Africa is related to the type of research questions that are investigated by scientists on the continent more so than the lack of resources. Our paper, Gaoue et al. (2018), which received the 2019 Julie Denslow prize was the result of an effort for such capacity building in Africa. The goal was to create efficient north-south scientific collaborations geared toward the sustained scientific production in peer-reviewed journals. Our paper was the result of a collaboration with Armand Natta (Figure 1a), a professor at the University of Parakou in Benin and two undergraduate students at the same institution. In this collaboration, I was more interested in the co-development of research ideas and co-publication.

After discussing different ideas for ecological research using study systems in Benin, Natta and I decided to investigate the effects of recurrent fruit harvesting by local farmers on the reproductive performance of Pentadesma butyracea (Clusiaceae) and how this disturbance may change plant investment in clonal versus seed-based reproduction (Gaoue et al. 2018). We were also interested in answering a follow-up question about how greater investments in clonal reproduction in disturbed populations can demographically buffer these populations (Gaoue et al. 2017). These two research questions were proposed to two undergraduate students, Choukouratou Gado (Figure 1b) and M’Mouyohoun Kouagou (Figure 1c), for their engineering degree theses at the University of Parakou. Under my co-supervision with Natta, the students developed their research proposals and conducted fieldwork to collect the data. I worked with both students training them on biological data analysis using R. The goal of this whole process was to train the students in proposal writing, field research planning, data collection, analysis, and scientific writing. Working through this process with the students improved their ability in statistical analysis and confidence in scientific writing. We produced two papers from this project including the paper that was the winner of the Julie Denslow prize (Gaoue et al. 2017, 2018). As it is often the case for most manuscripts, both papers were rejected previously and went through several revisions before they were published. It was interesting to have both students and their co-supervisor be part of this process and witness the behind the scene process of peer-reviewed publication.

Most publications by African scientists target local or regional journals (Tijssen 2007). Publication in these journals is often quick with limited peer-review. Rejection in these local journals is also less frequent than in top tier peer-reviewed journals. Therefore, co-authors were surprised by the lengthy and elaborated process of publishing this paper in Biotropica. Co-developing the research and engaging in the publication process with my collaborators were beneficial for all of us. This was an opportunity for me to develop a new study system and also get involved in capacity building beyond my university. The collaboration provided my co-authors with an opportunity to be part of a different kind of publication process and encouraged them to target international journals for their own work. Particularly for the students, this was the beginning of their career in academia and development. Kouagou went on to receive his master in biostatistics. Kouagou is currently doing his PhD, which I co-supervise with Armand Natta, on the synergistic effects of forest fragmentation and seed harvest on the dynamics of Pentadesma butyracea. Over the years, Kouagou acquired important skills in statistics and mathematical modeling, and he is now giving back by training several undergraduates and graduate students at his university to analyze their data. Gado was able to use the experience; she acquired working on our project to develop her master project on the ecological economics of Pentadesma butyracea. She is also working as a regional development officer in Benin.

I learned that capacity building while doing science is a slow and challenging process. This takes patience and also willingness to collaborate on both parts. I was fortunate to be part of this collaboration with colleagues at the University of Parakou, and this serves as a platform to develop several other collaborative projects with scientists in Africa. This includes studying the link between functional traits and population demography (Amahowe et al. 2018), the influence of road on the dynamics of plant communities in biosphere reserves (M’Woueni et al. 2019), and the population dynamics of mangroves (Gaoue & Yessoufou 2019). Several other collaborative projects are ongoing on the link between population and community level processes and theoretical ethnobotany.

Orou G. Gaoue

Department of Ecology and Evolutionary Biology, University of Tennessee Knoxville, TN 37996, USA. Email: [email protected]

Gabriela S. Adamescu, Andrew J. Plumptre, Katharine A. Abernethy, Leo Polansky, Emma R. Bus,h Colin A. Chapman, Luke P. Shoo, Adeline Fayolle, Karline R. L. Janmaat, Martha M. Robbins, Henry J. Ndangalasi, Norbert J. Cordeiro, Ian C. Gilby, Roman M. Wittig, Thomas Breuer, Mireille Breuer-Ndoundou Hockemba, Crickette M. Sanz, David B. Morgan, Anne E. Pusey, Badru Mugerwa, Baraka Gilagiza, Caroline Tutin, Corneille E. N. Ewango, Douglas Sheil, Edmond Dimoto, Fidèle Baya, Flort Bujo, Fredrick Ssali, Jean-Thoussaint Dikangadissi, Kathryn Jeffery, Kim Valenta, Lee White, Michel Masozera, Michael L. Wilson, Robert Bitariho, Sydney T. Ndolo Ebika, Sylvie Gourlet-Fleury, Felix Mulindahabi, and Colin M. Beale. 2018. Annual cycles are the most common reproductive strategy in African tropical tree communities. Biotropica 50:418-430.

After finishing my studies, I was interested in handling large data sets and working with R programming language, because I found it to be great at answering my scientific questions during my degree. One day, I contacted my future to be supervisor, Colin Beale, whom I knew had an interest in the kind of work I was looking for. This was when I first found out about the African sites I would have the chance to study in the following year. I was extremely happy to be given the opportunity to handle 12 African sites with more than 12,000 trees and excited to uncover their secrets in terms of phenology patterns, and relationship with the African climate hallmark (Figure 2). The story of these sites captured my attention immediately, so I took the decision to pursue my Masters studies and to take on this challenging experience. I have not worked with tree phenology before, and everything was completely new to me. However, being a nature lover and passionate about research and unmet world challenges proved to be a great asset, helping me to persistently navigate through this unknown world of African tree phenology (Figure 3).

Phenological studies have been conducted in temperate systems where changes in phenology due to climate change have been reported, and measurements have been already taken to protect endangered species. On the other hand, the phenology of tropical plants is poorly understood, due both to the paucity of long-term data sets and the complexity of individual patterns. This research was the first one to build a bigger phenological picture of the African tropical forests via a cross-continental comparison of the flowering and fruiting cycles at each site, using Fourier analysis.

Plant phenology is directly linked to animals and the entire ecosystem. Hence, phenological complementarity between plants and animals is crucial for the ecosystem organization, processes, and function. Changes in plant phenology can lead to various cascading effects on the entire ecosystem and cause phenological mismatch between plants and animals cycles. We conducted this study at 12 sites across Africa, which allowed us to compare and contrast individual tree species spatially and temporally. Individual species analysis is an important approach, as it reveals the wide variety of phenological patterns tropical plants have. Since there is little information about fruiting and flowering patterns of individual tree species in the African tropical forests, filling the gaps was necessary.

To assess the major cyclic patterns for flowering and fruiting at the sites, we used Fourier analysis to identify dominant cycles per individual tree. Fourier analysis requires continuous regular data collection, which was done at each site by trained assistants between 6 and 18 years. We assessed the smoothed spectral estimate for each individual tree and extracted the cycle frequency with the highest power, representing the strongest cycle in the data.

We concluded that across all sites, more trees flowered and fruited annually than sub-annually (more than once a year) or supra-annually (above 12 months), however, sub-annual flowering cycles and supra-annual fruiting patterns were present at all sites. Some sites had a minority of individual trees reproducing annually; however, no site had an absence of annually reproductive trees, in contrast to what we expected according to the literature. Seasonality at most sites covers two wet and two dry seasons, providing potential for environmental cues at a sub-annual cycle length but we found relatively low frequencies of sub-annual cycling.

What is exciting about our results is that they provide an important baseline from which future changes in seasonality and cycle length can be assessed across the continent. Given the complexity of individual responses, further understanding about the triggers of phenophase (individual flowering and fruiting), and how climate change may affect this aspect of tropical forest ecology, will require widespread measurement and recording of local climate variables alongside continued collection of phenological data. We showed that there is considerable variation in the frequency of different phenological cycles at different sites and that there is some geographic patterning in the distribution of site-specific phenological cycle profiles (Figure 4).

Finally, I am extremely pleased that our results got materialized in a published paper in Biotropica, especially because this study brought together the work of many passionate researchers who collected data for scientific purposes at different sites across the continent. The nomination for Peter Ashton Prize is a great honor for all the authors involved in this massive work. It also encourages future work on the phenology of African tropical forests under the influence of global warming, work that is becoming more and more critical now, when we are trying to understand and fight the ecological crisis we are facing.

Gabriela Simina Adamescu

University of York, United Kingdom and Gabriela Simina Adamescu PFA, Bucharest, Romania