Spotlight Series: Pulchérie Bissiengou & the challenges of taxonomy

Dr. Pulchérie Bissiengou is the Head Assistant of National Herbarium of Gabon. She is also a co-PI of ForestGEO’s Rabi, Gabon plot, where she got her start with the ForestGEO network in 2016. Pulchérie’s research focuses on the systematics and phylogeny of the Ochnaceae family, more precisely the African genus Campylospermum. She loves working in the field to identify plant species. 

When did you realize you wanted to be a scientist/work in forest ecology? How did you decide to go down this career path?

I realized that I wanted to be a scientist during the second year of my studies at the University of Gabon. There was a practical fieldwork course that allowed students to learn about various ecosystems within Gabon, which is my country. The discovery of these ecosystems such as the canyons and mangroves amazed me because because these ecosystems were not familiar to me. To know more about these ecosystems, I had to pursue my studies in the field of systematics and plant diversity to obtain a PhD degree. This degree enabled me to join the National Herbarium of Gabon, whose mission, among others, is to describe plants and their ecology. This structure allows me to know several families of plants and the associated ecosystems.

What led you down the path to your current job? What has been your biggest challenge in getting to this point in your career?

In Gabon, many plants are still unknown and even for those that are known, there is often a lack of adequate documentation. Many trees are exploited for timber production, but it is likely that the general public would not be able to recognize these trees in the wild because of the lack of tools that allow them to identify these trees. Botanists, such as myself, provide these tools, in various forms (field guide, book of flora), to identify each tree found in Gabon. This is the reason why I chose to be a botanist.

In order to make the general public aware of the different types of plants, botanists have to go into the field to collect these plants. My biggest challenge, which has remained the same my whole career, is collecting data in areas that are difficult access because of their remote location. As a result, some areas in Gabon are little known or remain totally unknown botanically to me.

When did you first get involved in the ForestGEO network?

I started to take part in the ForestGEO network in 2016 when we started the second census of the Rabi plot. I am the field manager and data coordinator, so my duties include training field teams and describing plants encountered in the field. I also process the data collected in the field and am involved in some publications concerning the plot data.

What is the most interesting or unique aspect of your site?

The Rabi plot is within a protected area, where private sector companies operate (Assala, former Shell Gabon, an oil company and CBG, a logging one). Specifically, the Rabi plot sits on an oil concession and a logging concession, which results in protection from illegal hunting and logging. No human communities exist in the immediate vicinity of the plot, nor are historic communities known. Although oil field workers are housed in nearby camps, oil concession regulations restrict access, vehicle speed, and hunting that may influence biodiversity. Areas adjacent to the oil field are largely public lands or logging concessions. At the Rabi plot we gain valuable insight into the south Gabonese littoral lowland forest at a location where natural resources are extracted in relative harmony with the environment.

What questions are you currently addressing in your research/site?

One question concerns the role of pathogens and mycorrhizae on the latitudinal gradient of plant diversity. Specifically, we aim to test how pathogens and mycorrhizae interact to affect forest diversity and how this varies with the type of mycorrhizae. In addition, we will test how climate and soil characteristics influence the global distribution of these important groups of plant-associated microbes.

There is also the question of tree-fungus interactions, which focuses on the case of Phylloporia spp, a parasitic fungus on Warneckea spp. and forest litter dynamics.  The mycological inventories carried out in the Rabi plot have increased mycological knowledge in Gabon. Five new species of fungi have already been described: Phylloporia flabeliforma, Phylloporia gabonenis, Phylloporia inonotoïdes, Phylloporia littoralis, Phylloporia rinoreae. 

These parasitic fungi grow on the trunks of living trees, including Warneckea spp, Dichostema glauscences, Crotonogyne gabonenis and Memecylon sp, which are among the twenty most abundant species in the Rabi plot. Phylloporia are described as parasitic species but their impact on tree growth is very poorly documented to date.

In 2018, we initiated a comparative study on the evolution of DBH of parasitized and non-parasitized trees, taking as a starting point the DBH measurements of 2012. We would like to carry out further measurements on parasitized and non-parasitized trees recorded in 2018 in order to be able to analyse the evolution of DBH, but also to evaluate the effects of parasites on health and performance of the parasitized trees. To this DBH parameter, we propose to develop a protocol on the study of litter dynamics, by combining measurements of leaf indices of parasitized and non-parasitized trees on the trees surveyed in 2018. The objective is to be able to quantify the annual litterfall of contaminated and non-contaminated trees within the same species to compare the leaf turnover of parasitized and non-parasitized trees.

What kind of capacity building opportunities does your site provide for students, early-career researchers, and the local community?

Local capacity building is an essential component of the plot activities. The plot supports the studies of students by participating in the field activities. This allows these early career professionals to gain valuable experience in collecting data and preparing reports and presenting their results under the guidance of experienced scientists. Some students have developed skills to work with ArcGIS mapping software to review deforestation in Gabon. Others prepared a photo database using Picasa software.

Field activities included training of Gabonese students and technicians. This training was a combination of brief classroom discussions followed by an extended period in the field using a hands-on workshop format. Participants learned methods for measuring, monitoring and reporting on all the dominant pools that make up ecosystem carbon stocks.

What is your favorite part about your work?

My favourite part of my work is being in the field to identify plants.

What do you like to do when you’re not studying forest dynamics? 

What I like to do when I am not studying forest dynamics is to spend time with my family.

Web Presence: ForestGEO Rabi Plot Webpage | Plateforme de l'Herbier National du Gabon

Select Publications:

Decock, C, Yombiyeni, P and Memiaghe, H (2015) Hymenochaetaceae from the Guineo-Congolian rainforest: Phylloporia flabelliforma sp. nov. and Phylloporia gabonensis sp. nov., two undescribed species from Gabon. Cryptogamie, Mycologie 36 (4): 1-20. http://dx.doi/10.7872/crym/v36.iss4.2015.1

Memiaghe, H, Lutz, J, Korte, L, Alonso, A and Kenfack, D (2016) Ecological Importance of small-diameter trees to the structure, diversity and biomass of a tropical evergreen forest at Rabi, Gabon. PLOS ONE, 1-15. http://dx.doi.org/10.1371/journal.pone.0154988

Ekomo Nguema, D, Memiaghe, H, Bissiengou, P, Mounoumoulossi, E, Alonso, A and Kenfack, D (2017) Rabi, Ogooue-Maritime Province, Gabon. Plants of the Rabi Plot – Rubiaceae. Field guide.

Ekomo Nguema, D, Memiaghe, H, Bissiengou, P, Mounoumoulossi, E, Alonso, A and Kenfack, D (2017) Rabi, Ogooue-Maritime Province, Gabon. Plants of the Rabi Plot – Ebenaceae. Field guide.

Labrière, N, Tao, S, Chave, J, Scipal, K, Le Toan, T, Abernethy, K, Alonso, A, Barbier, N, Bissiengou, P, Casal, T, Davies, S, Ferraz, A, Hérault, B, Jaouen, G, Jeffery, K, Kenfack, D, Korte, L, Lewis, S, Malhi, Y, Memiaghe, H, Poulsen, J, Rejou-Mechain, M, Villard, L, Vincent, G, White L, and Saatchi, S (2018) In Situ reference datasets from the TropiSAR and AfriSAR campaigns in support of upcoming spaceborne biomass missions. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 2018: 1939-1404

Engone Obiang, N, Kenfack, D, Picard, N, Lutz, J, Bissiengou, P, Memiaghe, H, Alfonso, A (submitted) Determinants of spatial patterns of canopy tree species in a tropical evergreen forest, in Gabon. Journal of Vegetation Science. http://doi.org/10.1111/jvs.12778.