Categorie archief: Researchreports

Children in the Mbendjele BaYaka society: diet, foraging, and acquisition of skills and botanical knowledge

A research report by Prof. Dr. Karline R. L. Janmaat (Instituut voor Biodiversiteit en Ecosysteem Dynamica, Universiteit van Amsterdam) on master thesis work carried out by Jorin Veen in 2019-2020.

Modern hunter gatherers need a wide variety of skills and knowledge to collect and consume the available resources. It has been hypothesized that the extended juvenile period in humans has enabled us to acquire these skills and knowledge. To study this, we focused on Mbendjele foragers in the northern part of the Republic of Congo. They live in semi-nomadic egalitarian societies, where food items are widely shared on demand. The children are known to start foraging independently from a young age, offering a unique opportunity to study their diet, foraging behaviour, and acquisition of skills and knowledge.

Research team on way to the forest. On a boat on the beautiful Motaba river together with – from left to right – prof. dr. Karline R.L. Janmaat, Moise Dzabatou, Bryndan O.C.M. van Pinxteren, and Merveille Dzabatou.

            Before data collection, the informed oral consent of the children, together with that of their parent(s) and/or caretaker(s), was obtained. In total, 27 children were accompanied during their foraging trips over a rainy period of six months in 2016 (March – August) and during a dry period of five months in 2019 – 2020 (November – March). The data were collected using a combination of a GPS and a voice recorder. In addition, the botanical knowledge of 17 children was tested using pictures of several parts (fruit/seed, leaf, trunk, bark) of foraging-related plant species known to produce edible fruits or seeds.

Flowers as hair decorations. After a full day of collecting fish, some of the girls decided to decorate their, mine, and Bryndan’s hair with flowers.

            It was found that the children spent most time collecting and eating fruits and tubers, with other food items such as caterpillars and honey being highly seasonal. Interestingly, the results indicated that boys spent more time collecting fruits (and honey) whereas girls spent more time collecting tubers (and fish). This resembles a sexual division in foraging behaviour previously observed in adults. Since sharing is a key value in this society, equal proportions of fruits and tubers were eaten by both boys and girls. Finally, the botanical knowledge of the children improved with increasing age, indicating a learning curve of the different foraging-related plant species during childhood.

            These results will, hopefully, provide new insights in the diet and foraging behaviour of modern hunter-gatherers and their acquisition of foraging-related skills and knowledge. In addition, I hope that it will contribute to the protection of the unique lifestyle of the Mbendjele themselves. Almost, if not all, Mbendjele are currently residing in logging concessions. This will most definitely reduce the available wild resources, which probably explains that more than half of their contemporary diet consists of agricultural foods.            

Specifically, I would like to thank my supervisor Prof. Karline Janmaat and Bryndan van Pinxteren for their major contributions, and Haneul Jang and Vidrige Kandza for data collected in 2016. Additionally, I would like to thank Moise Dzabatou and his daughter Merveille Dzabatou for local help with transport and translations. Also, the University of Amsterdam, Max Planck Institute, and the Institut de Recherche en Sciences Exactes et Naturelles (IRSEN) have contributed. Eternal gratitude goes towards the Mbendjele themselves, for welcoming me in their camp, letting me learn their language and participate in their highly valued dance and music activities. Finally, I would like to thank Treub Maatschappij for enabling this research and valuable personal experience. Like the Mbendjele would say: Esengo ike!

Disclaimer: Informed oral consent was obtained of the children and their parent(s)/caretaker(s), both for participation in the research and the use of their pictures. For further use of the pictures, permission has to be asked to Prof. Karline Janmaat and Jorin Veen.

Reconstructing the Eocene to Oligocene history of Sapotaceae in Myanmar

A research report by Daniel Perez-Pinedo (Instituut voor Biodiversiteit en Ecosysteem Dynamica, Universiteit van Amsterdam). The resulting masters thesis has been awarded the East-West Seed Graduation Prize for Plant Sciences 2020 of the The Royal Holland Society of Sciences and Humanities.


The Eocene–Oligocene Transition (EOT) (~33.9Ma) is characterized by climate cooling and paleogeographic change and constitutes one of the most remarkable time intervals in the Cenozoic. This climate transition had a major impact on SE Asia, one of the most biodiverse areas and tectonic active regions in the world. However, terrestrial vegetation response in SE Asia across the EOT transition remains poorly understood.

The Cenozoic vegetation dynamics of Myanmar have been scarcely documented, yet are of great interest to unravel paleogeographic and paleoclimatic history. The family Sapotaceae is of particular concern since it has been a dominant component of SE Asian megathermal lowland wet forests ever since the early Eocene. However, their genera delimitation, origins, and direction of evolutionary change across the EOT remain uncertain. The Central Myanmar Basin (CMB; Myanmar) holds a sedimentary record ranging from upper Eocene – lower Oligocene, which is subdivided into the Yaw and Shwezetaw formations respectively. This sedimentary record presents an excellent opportunity to study the development of the SE Asian forests across the EOT.


In this project I joined the Myanmar Paleoclimate and Geodynamics Research group which focuses on geodynamic, tectonic, paleoclimatic, and paleoenvironmental studies of the Burmese sedimentary archives over the last 120 Ma. The last MyaPGR expedition took place in January 2020. It was led by Dr. Alexis Licht and consisted of Dr. Pierrick Roperch and PhD candidate Jan Westerweel (both from Université de Rennes), Dr. Amy Gough (Royal Holloway, University of London), and myself (Universiteit van Amsterdam). The main goal of the expedition was to report changes in palyno-assemblages across the EOT revealed by the main pollen markers.

The expedition operated in the south of the CMB located at the southern edge of the eastern Himalayan orogen and the Indochinese margin (Figure 1). We traveled to the Minbu sub-basin and visited 6 geological sections of scientific interest where we sampled for pollen, biological markers, fossil wood, amber, and also collected samples in order to conduct paleomagnetic dating (Figure 2). In particular we focused on the Yaw and the Shwezettaw formations, ranging from the late Eocene to the Early Oligocene respectively.

Figure 1: Map of Myanmar and background elevation and sampling area in the Minbu sub-basin

Figure 2: The expedition team observing an outcrop where geological strata of Paleogene age are exposed (Myanmar). Photo credits: Amy Gough

The analysis

The samples were processed at the University of Amsterdam and pollen were examined under light microscopy (LM) and scanning electron microscopy (SEM). The palynological data were analyzed with a cluster analysis tool CONISS that is based on a broken stick model. We also applied ordination multivariate analysis such as Detrended correspondence analysis (DCA) and non-metric multidimensional scaling (NMDS). We observed differential palyno-assemblages resembling changing vegetation across the tropical Eocene into the cooler Oligocene. We also reported different depositional environments across the transition. We interpreted these changing trends to be derived from potential global cooling, increased aridity, and the progressive uplift of the Indo-Burman Ranges (IBR). The EOT reveals itself as one of the main drivers of paleoenvironmental dynamics leading to a pronounced terrestrial reorganization within terrestrial vegetation related to climatic and biogeographic dynamics in Myanmar, possibly extensive to SE Asia.


Having had the opportunity of going to the tropics to conduct fieldwork has resulted in a greater personal engagement in the project as well as a better understanding of the topic. I acquired a better grounded in situ understanding of both the ecological context (vegetation, forest composition) and the geological context regarding lithology and sedimentology of the outcrops of our interest in the Minbu sub-basin. Finally, having had the opportunity of working as a junior member of a well-structured professional research team which consisted of both international and Burmese researchers was both enriching and professionally and culturally challenging.

Symbiotic coral-dwelling crabs on Bonaire’s reefs

Dr. S.E.T. van der Meij and S. Bähr (GELIFES, University of Groningen , Groningen, The Netherlands)

Bonaire, Dutch Caribbean – 26 July – 17 August 2019

Coral reefs encompass the highest biodiversity of any marine ecosystem. Stony corals provide a large number of habitats that are home to various invertebrate species, many of which live in a close symbiotic relationship with a specific host coral. In an environment that is teeming with symbiotic relationships the minute and easily overlooked coral-dwelling gall crabs of the family Cryptochiridae represent a prime example of obligate symbiosis. These crabs are named after their close relationship with their coral hosts; they cause the development of a gall by modifying their hosts’ tissue.

The reefs along Bonaire’s coast are amongst the healthiest reefs in the Caribbean, however they are relatively understudied compared to nearby Curaçao and other islands with a strong research infrastructure. In this study we aimed to collect occurrence data of three Atlantic gall crab species (Fig. 1) over depth intervals along the Bonaire coast, to better understand the distribution of symbiotic species on coral reefs. In combination with coral cover measurements the results of this study provided us with baseline data about the status of Bonaire’s reef. Moreover, using the same approach as a similar study carried out on the reefs off Curaçao in 2015, it allows us to compare the results between the two islands.

We studied 25 dive sites along the west coast of Bonaire and around Klein Bonaire using 5-m2 belt transects (10m x 0.5m) at three different depths (8m, 12m, 18m), resulting in a surveyed area of 375 m2. Within each transect we measured the diameter of all corals known to host gall crabs, and counted the number of dwellings on each individual colony.

Our observations of the crabs Troglocarcinus corallicola and Kroppcarcinus siderastreicola represent new species records for Bonaire. Direct comparisons of coral cover data and gall crab density between Curaçao and Bonaire provides interesting insights in the status of the two reef systems. On Bonaire 19 out of 22 known host corals were observed in the transects, compared to 15 out of 22 of Curaçao. Strikingly, the number of examined coral colonies on Bonaire was with 4023 more than twice as high as the number of colonies examined on Curaçao (1874 colonies). The crab density of Opecarcinus hypostegus was with 6,3 crabs per m2, however, exactly the same at both localities. Troglocarcinus corallicola had with 5,22 crabs/m2 a slightly higher density on Bonaire than on the reefs off Curaçao (4,02 crabs/m2). Unfortunately the dwelling data for K. siderastreicola had to be excluded from the analyses due to some misidentifications of their dwellings in part of the study. 

Our results suggest that Bonaire’s reef system has a significantly higher coral cover than the reefs on Curaçao. Using further statistical analyses we will check for significant species level differences between the two islands, as well as between the various dive sites off Bonaire. Certain sites are heavily impacted by divers or industry (e.g. cruise ships, salines), whereas others are further away from human activities or rarely visited by divers – and we are keen to see if this impacts the distribution of the symbiotic gall crabs.

Figure 1: Dwellings with gall crabs found on corals off Bonaire. (A) Opercarcinus hypostegus in Agaricia lamarcki, (B) Kroppcarcinus siderastreicola in Siderastrea siderea, (C) Troglocarcinus corallicola in Orbicella annularis. Pictures: Pieter de Groot.

Palliative care needs and preferences in Ethiopia

Dr. J.J. Beltman and drs. M. de Fouw (Leids Universitair Medisch Centrum, Leiden, The Netherlands)

In Sub-Saharan Africa where life expectancy is short, supportive and palliative care for severely ill patients are hardly available. Ethiopia is one of the countries where lack of access to pain relief and palliative care are apparent. In our study we assessed palliative care and support programs for women, mostly affected by cervical cancer and breast cancer. Breast and cervical cancer are the leading cancers among women in Ethiopia, with 15244 and 6294 new cases each year.

Most women identified with cervical and breast cancer present in advanced stage where curative treatment is no longer an option. Comprehensive palliative care services are needed but scarce, strong analgesics like morphine are hardly available and knowledge of palliative services in health facilities is limited.

We aimed to understand the current practices of palliative care, and the needs and preferences of both patients and their caregivers. We conducted in-depth interviews with terminally ill women (34) and their caregivers (27), and key informant interviews (16) with community leaders, religious leaders, health care professionals and policy makers.

All patients received support from the palliative care programs, but stated that it was insufficient to meet their needs. Most women (4 out of 5) suffered from moderate to severe pain, half of the women frequently experienced moderate to severe difficulties with sleeping or eating.

“She (the volunteer provider) has been caring. However, I am not happy and lose hope when my pain comes back. I then feel uncertain about my life. I feel like am dying. It is bad to live under uncertainty, losing my ability to make decisions about myself. The volunteer at times fails to help under such circumstances” (42 years old female patient)

Besides pain, and difficulties with sleeping or eating women suffered from other complaints like cough and vaginal bleeding, that strongly limited their daily activities.

I bleed every time. It clots and clots and brought offensive smell since I do not have support to clean it and of course no one comes closer. I got weaker and weaker. Only recently volunteers came to help me – thank God.” (38 year old  female patient)

Women felt very worried about their situation, and did not often talk about their worries and concerns with their caregivers. Religion did support women in feeling more hopeful about their situation.

Caregivers were often related to the patients, in half of the cases a daughter or son cared for their own mother. Neighbours and other community members supported less than 1 in 4 patients. Most caregivers experienced sad feelings while providing support to terminally ill women and experienced the work as consuming. At the same time, they felt confident about the care they were providing although they missed information on the diagnosis, signs and symptoms.

Health care professionals, community leaders, religious leaders and policy makers recognized the existing gap in palliative care provision and lack of knowledge on palliative care services. They pointed out the lack of organization of care, lack of skilled providers, lack of budget and low priority that is given to palliative care services.

During our study we found that only a selected group of women was included in the support programs, although the programs define palliative care in a broad definition including chronic illnesses like diabetes and hypertension. Considering the population size in the areas where the programs are active, many women with palliative care needs are not identified.

Our study demonstrates that there is an unmet need for palliative care services, that palliative care services should focus more on pain and symptom relief including training of related caregivers, and palliative care services should be integrated with existing community networks, religious structures and local and national health systems.

One of the women receiving palliative care in her own home, Sidama zone, Ethiopia