Simone Messina, a PhD student in the Behavioral Ecology and Ecophysiology Group in the Department of Biology at the University of Antwerp, shares the basis of his recent publication, “Glucocorticoids link forest type to local abundance in tropical birds”, as well as his opinion on the “highs and lows” associated with being an ecologist.

What is the background behind your paper?

View of the Segama river and surrounding forest from the suspension bridge in the Danum Valley Field Center, Sabah, Malaysian Borneo. Photo credit Simone Messina
View of the Segama river and surrounding forest from the suspension bridge in the Danum Valley Field Center, Sabah, Malaysian Borneo. Photo credit Simone Messina

The integrity of tropical forests and of their biodiversity are increasingly threatened by human activities. Selective logging is the main type of forest disturbance in the tropics, which consists of harvesting the biggest marketable trees from the forests. Such disturbed habitats are generally perceived as highly degraded, thus they are particularly susceptible to conversion to palm oil plantations or other land-uses. However, recent studies found that negative effects of selective logging on biodiversity are limited compared to other land-use changes. Thus, given the limited extent of remaining undisturbed tropical forests, selectively logged forests are increasingly recognised as important habitat to preserve for reaching global goals of biodiversity conservation. It is therefore important to study how this new habitat differs from the original forest, aiming to improve knowledge and techniques to maximize biodiversity conservation.

What is your paper about?

Our paper aimed to investigate if physiological stress mediated by the glucocorticoid hormone corticosterone explains changes in abundances of birds living in unlogged and selectively logged forests.

Glucocorticoids are one particular group of hormones that regulate many important body functions in animals, including feeding behaviour, reproductive activity, or energy management. The activity of glucocorticoids may be particularly relevant under new environmental conditions to regulate the energy budget.

We measured the concentration of corticosterone in feathers of 10 understory bird species living in both unlogged and selectively logged forests of Borneo. Corticosterone measured in feathers is considered an integrative measure of the circulating hormone during the time of growth of the feather. This technique is only weakly invasive for the animal and feathers are easy to collect and store.

Our main result was that bird species with higher concentrations of corticosterone in either unlogged or selectively logged forest in a year, were less abundant in the same forest the following year. This result suggests that glucocorticoid hormones may link current environmental conditions to individual fitness, translating into effects on population abundance.

Did you have any problems gathering your data?

Setting-up transects for mist-netting. Photo credit Cindy Cosset.
Setting-up transects for mist-netting. Photo credit Cindy Cosset.

The biggest challenge to work in the tropics was managing all of the bureaucratic paperwork! Prior to starting work in the forest, researchers have to apply for permits. This activity requires organization, coordination between all members involved, and it needs to be planned well in advance because of long waiting time for the approvals. However, once you are done with such paperwork, the problems in the jungle are much easier to handle. For example, you may reach your transect early in the morning and find that a huge tree fell down on your nets, or you may sense elephants around your plot and you don’t really want to meet them, or eventually it may start heavily raining while you are running your transect and you fly down from a muddy slope in a rush to close the nets.

What’s your current position?

I will be a PhD student for few more months, and I am now looking for new opportunities to keep working in academia. It would be amazing for me to start a new project in a tropical forest, but I will also consider other possibilities.

What is the worst thing about being an ecologist?

The rufous-collared kingfisher (Actenoides concretus) is a marvelous, uncommon bird to catch in the net. Photo credit Tanith Hackney-Huck.
The rufous-collared kingfisher (Actenoides concretus) is a marvelous, uncommon bird to catch in the net. Photo credit Tanith Hackney-Huck.

The worst thing about being an ecologist is when you have to spend weeks struggling with new techniques for data analyses. Statistical analyses are very important for scientists, and they are updated continuously for more complex and accurate outcomes. To continuously update data using the most recent techniques of data analysis, ecologists are often forced to forget about nature for a while.

What is the best thing about being an ecologist?

The best thing about being an ecologist is fieldwork, because personal experience with nature is the best way to really understand how ecosystems work. I loved staying for months in the jungle, waking up at 4 am and going to sleep at 9 pm. I enjoyed walking through the forest every day and I particularly liked the feeling of wonder when we caught in nets some uncommon birds or flying lizards, or when we scored orangutans, gibbons or even a colugo resting on a tree next to one mist-net.

You can read Simone’s paper here.